8592 строки
206 KiB
C
8592 строки
206 KiB
C
/*
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* kernel/sched/core.c
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*
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* Kernel scheduler and related syscalls
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*
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* Copyright (C) 1991-2002 Linus Torvalds
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*
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* 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and
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* make semaphores SMP safe
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* 1998-11-19 Implemented schedule_timeout() and related stuff
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* by Andrea Arcangeli
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* 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar:
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* hybrid priority-list and round-robin design with
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* an array-switch method of distributing timeslices
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* and per-CPU runqueues. Cleanups and useful suggestions
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* by Davide Libenzi, preemptible kernel bits by Robert Love.
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* 2003-09-03 Interactivity tuning by Con Kolivas.
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* 2004-04-02 Scheduler domains code by Nick Piggin
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* 2007-04-15 Work begun on replacing all interactivity tuning with a
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* fair scheduling design by Con Kolivas.
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* 2007-05-05 Load balancing (smp-nice) and other improvements
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* by Peter Williams
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* 2007-05-06 Interactivity improvements to CFS by Mike Galbraith
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* 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri
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* 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins,
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* Thomas Gleixner, Mike Kravetz
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*/
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/nmi.h>
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#include <linux/init.h>
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#include <linux/uaccess.h>
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#include <linux/highmem.h>
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#include <asm/mmu_context.h>
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#include <linux/interrupt.h>
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#include <linux/capability.h>
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#include <linux/completion.h>
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#include <linux/kernel_stat.h>
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#include <linux/debug_locks.h>
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#include <linux/perf_event.h>
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#include <linux/security.h>
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#include <linux/notifier.h>
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#include <linux/profile.h>
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#include <linux/freezer.h>
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#include <linux/vmalloc.h>
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#include <linux/blkdev.h>
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#include <linux/delay.h>
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#include <linux/pid_namespace.h>
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#include <linux/smp.h>
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#include <linux/threads.h>
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#include <linux/timer.h>
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#include <linux/rcupdate.h>
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#include <linux/cpu.h>
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#include <linux/cpuset.h>
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#include <linux/percpu.h>
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#include <linux/proc_fs.h>
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#include <linux/seq_file.h>
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#include <linux/sysctl.h>
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#include <linux/syscalls.h>
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#include <linux/times.h>
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#include <linux/tsacct_kern.h>
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#include <linux/kprobes.h>
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#include <linux/delayacct.h>
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#include <linux/unistd.h>
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#include <linux/pagemap.h>
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#include <linux/hrtimer.h>
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#include <linux/tick.h>
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#include <linux/debugfs.h>
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#include <linux/ctype.h>
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#include <linux/ftrace.h>
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#include <linux/slab.h>
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#include <linux/init_task.h>
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#include <linux/binfmts.h>
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#include <asm/switch_to.h>
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#include <asm/tlb.h>
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#include <asm/irq_regs.h>
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#include <asm/mutex.h>
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#ifdef CONFIG_PARAVIRT
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#include <asm/paravirt.h>
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#endif
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#include "sched.h"
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#include "../workqueue_sched.h"
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#include "../smpboot.h"
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#define CREATE_TRACE_POINTS
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#include <trace/events/sched.h>
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void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period)
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{
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unsigned long delta;
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ktime_t soft, hard, now;
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for (;;) {
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if (hrtimer_active(period_timer))
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break;
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now = hrtimer_cb_get_time(period_timer);
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hrtimer_forward(period_timer, now, period);
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soft = hrtimer_get_softexpires(period_timer);
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hard = hrtimer_get_expires(period_timer);
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delta = ktime_to_ns(ktime_sub(hard, soft));
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__hrtimer_start_range_ns(period_timer, soft, delta,
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HRTIMER_MODE_ABS_PINNED, 0);
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}
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}
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DEFINE_MUTEX(sched_domains_mutex);
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DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
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static void update_rq_clock_task(struct rq *rq, s64 delta);
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void update_rq_clock(struct rq *rq)
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{
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s64 delta;
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if (rq->skip_clock_update > 0)
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return;
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delta = sched_clock_cpu(cpu_of(rq)) - rq->clock;
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rq->clock += delta;
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update_rq_clock_task(rq, delta);
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}
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/*
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* Debugging: various feature bits
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*/
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#define SCHED_FEAT(name, enabled) \
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(1UL << __SCHED_FEAT_##name) * enabled |
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const_debug unsigned int sysctl_sched_features =
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#include "features.h"
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0;
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#undef SCHED_FEAT
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#ifdef CONFIG_SCHED_DEBUG
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#define SCHED_FEAT(name, enabled) \
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#name ,
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static const char * const sched_feat_names[] = {
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#include "features.h"
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};
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#undef SCHED_FEAT
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static int sched_feat_show(struct seq_file *m, void *v)
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{
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int i;
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for (i = 0; i < __SCHED_FEAT_NR; i++) {
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if (!(sysctl_sched_features & (1UL << i)))
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seq_puts(m, "NO_");
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seq_printf(m, "%s ", sched_feat_names[i]);
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}
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seq_puts(m, "\n");
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return 0;
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}
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#ifdef HAVE_JUMP_LABEL
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#define jump_label_key__true STATIC_KEY_INIT_TRUE
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#define jump_label_key__false STATIC_KEY_INIT_FALSE
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#define SCHED_FEAT(name, enabled) \
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jump_label_key__##enabled ,
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struct static_key sched_feat_keys[__SCHED_FEAT_NR] = {
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#include "features.h"
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};
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#undef SCHED_FEAT
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static void sched_feat_disable(int i)
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{
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if (static_key_enabled(&sched_feat_keys[i]))
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static_key_slow_dec(&sched_feat_keys[i]);
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}
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static void sched_feat_enable(int i)
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{
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if (!static_key_enabled(&sched_feat_keys[i]))
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static_key_slow_inc(&sched_feat_keys[i]);
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}
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#else
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static void sched_feat_disable(int i) { };
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static void sched_feat_enable(int i) { };
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#endif /* HAVE_JUMP_LABEL */
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static ssize_t
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sched_feat_write(struct file *filp, const char __user *ubuf,
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size_t cnt, loff_t *ppos)
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{
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char buf[64];
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char *cmp;
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int neg = 0;
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int i;
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if (cnt > 63)
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cnt = 63;
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if (copy_from_user(&buf, ubuf, cnt))
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return -EFAULT;
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buf[cnt] = 0;
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cmp = strstrip(buf);
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if (strncmp(cmp, "NO_", 3) == 0) {
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neg = 1;
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cmp += 3;
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}
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for (i = 0; i < __SCHED_FEAT_NR; i++) {
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if (strcmp(cmp, sched_feat_names[i]) == 0) {
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if (neg) {
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sysctl_sched_features &= ~(1UL << i);
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sched_feat_disable(i);
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} else {
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sysctl_sched_features |= (1UL << i);
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sched_feat_enable(i);
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}
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break;
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}
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}
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if (i == __SCHED_FEAT_NR)
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return -EINVAL;
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*ppos += cnt;
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return cnt;
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}
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static int sched_feat_open(struct inode *inode, struct file *filp)
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{
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return single_open(filp, sched_feat_show, NULL);
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}
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static const struct file_operations sched_feat_fops = {
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.open = sched_feat_open,
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.write = sched_feat_write,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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};
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static __init int sched_init_debug(void)
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{
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debugfs_create_file("sched_features", 0644, NULL, NULL,
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&sched_feat_fops);
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return 0;
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}
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late_initcall(sched_init_debug);
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#endif /* CONFIG_SCHED_DEBUG */
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/*
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* Number of tasks to iterate in a single balance run.
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* Limited because this is done with IRQs disabled.
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*/
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const_debug unsigned int sysctl_sched_nr_migrate = 32;
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/*
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* period over which we average the RT time consumption, measured
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* in ms.
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*
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* default: 1s
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*/
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const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC;
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/*
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* period over which we measure -rt task cpu usage in us.
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* default: 1s
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*/
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unsigned int sysctl_sched_rt_period = 1000000;
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__read_mostly int scheduler_running;
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/*
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* part of the period that we allow rt tasks to run in us.
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* default: 0.95s
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*/
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int sysctl_sched_rt_runtime = 950000;
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/*
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* __task_rq_lock - lock the rq @p resides on.
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*/
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static inline struct rq *__task_rq_lock(struct task_struct *p)
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__acquires(rq->lock)
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{
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struct rq *rq;
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lockdep_assert_held(&p->pi_lock);
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for (;;) {
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rq = task_rq(p);
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raw_spin_lock(&rq->lock);
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if (likely(rq == task_rq(p)))
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return rq;
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raw_spin_unlock(&rq->lock);
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}
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}
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/*
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* task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
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*/
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static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
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__acquires(p->pi_lock)
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__acquires(rq->lock)
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{
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struct rq *rq;
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for (;;) {
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raw_spin_lock_irqsave(&p->pi_lock, *flags);
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rq = task_rq(p);
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raw_spin_lock(&rq->lock);
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if (likely(rq == task_rq(p)))
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return rq;
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raw_spin_unlock(&rq->lock);
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raw_spin_unlock_irqrestore(&p->pi_lock, *flags);
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}
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}
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static void __task_rq_unlock(struct rq *rq)
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__releases(rq->lock)
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{
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raw_spin_unlock(&rq->lock);
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}
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static inline void
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task_rq_unlock(struct rq *rq, struct task_struct *p, unsigned long *flags)
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__releases(rq->lock)
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__releases(p->pi_lock)
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{
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raw_spin_unlock(&rq->lock);
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raw_spin_unlock_irqrestore(&p->pi_lock, *flags);
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}
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/*
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* this_rq_lock - lock this runqueue and disable interrupts.
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*/
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static struct rq *this_rq_lock(void)
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__acquires(rq->lock)
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{
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struct rq *rq;
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local_irq_disable();
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rq = this_rq();
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raw_spin_lock(&rq->lock);
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return rq;
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}
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#ifdef CONFIG_SCHED_HRTICK
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/*
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* Use HR-timers to deliver accurate preemption points.
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*
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* Its all a bit involved since we cannot program an hrt while holding the
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* rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
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* reschedule event.
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*
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* When we get rescheduled we reprogram the hrtick_timer outside of the
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* rq->lock.
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*/
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static void hrtick_clear(struct rq *rq)
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{
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if (hrtimer_active(&rq->hrtick_timer))
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hrtimer_cancel(&rq->hrtick_timer);
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}
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/*
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* High-resolution timer tick.
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* Runs from hardirq context with interrupts disabled.
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*/
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static enum hrtimer_restart hrtick(struct hrtimer *timer)
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{
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struct rq *rq = container_of(timer, struct rq, hrtick_timer);
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WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
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raw_spin_lock(&rq->lock);
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update_rq_clock(rq);
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rq->curr->sched_class->task_tick(rq, rq->curr, 1);
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raw_spin_unlock(&rq->lock);
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return HRTIMER_NORESTART;
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}
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#ifdef CONFIG_SMP
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/*
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* called from hardirq (IPI) context
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*/
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static void __hrtick_start(void *arg)
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{
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struct rq *rq = arg;
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raw_spin_lock(&rq->lock);
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hrtimer_restart(&rq->hrtick_timer);
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rq->hrtick_csd_pending = 0;
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raw_spin_unlock(&rq->lock);
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}
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/*
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* Called to set the hrtick timer state.
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*
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* called with rq->lock held and irqs disabled
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*/
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void hrtick_start(struct rq *rq, u64 delay)
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{
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struct hrtimer *timer = &rq->hrtick_timer;
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ktime_t time = ktime_add_ns(timer->base->get_time(), delay);
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hrtimer_set_expires(timer, time);
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if (rq == this_rq()) {
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hrtimer_restart(timer);
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} else if (!rq->hrtick_csd_pending) {
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__smp_call_function_single(cpu_of(rq), &rq->hrtick_csd, 0);
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rq->hrtick_csd_pending = 1;
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}
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}
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static int
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hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu)
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{
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int cpu = (int)(long)hcpu;
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switch (action) {
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case CPU_UP_CANCELED:
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case CPU_UP_CANCELED_FROZEN:
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case CPU_DOWN_PREPARE:
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case CPU_DOWN_PREPARE_FROZEN:
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case CPU_DEAD:
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case CPU_DEAD_FROZEN:
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hrtick_clear(cpu_rq(cpu));
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return NOTIFY_OK;
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}
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return NOTIFY_DONE;
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}
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static __init void init_hrtick(void)
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{
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hotcpu_notifier(hotplug_hrtick, 0);
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}
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#else
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/*
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* Called to set the hrtick timer state.
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*
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* called with rq->lock held and irqs disabled
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*/
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void hrtick_start(struct rq *rq, u64 delay)
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{
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__hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0,
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HRTIMER_MODE_REL_PINNED, 0);
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}
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static inline void init_hrtick(void)
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{
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}
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#endif /* CONFIG_SMP */
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static void init_rq_hrtick(struct rq *rq)
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{
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#ifdef CONFIG_SMP
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rq->hrtick_csd_pending = 0;
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rq->hrtick_csd.flags = 0;
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rq->hrtick_csd.func = __hrtick_start;
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rq->hrtick_csd.info = rq;
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#endif
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hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
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rq->hrtick_timer.function = hrtick;
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}
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#else /* CONFIG_SCHED_HRTICK */
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static inline void hrtick_clear(struct rq *rq)
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{
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}
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static inline void init_rq_hrtick(struct rq *rq)
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{
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}
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static inline void init_hrtick(void)
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{
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}
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#endif /* CONFIG_SCHED_HRTICK */
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/*
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* resched_task - mark a task 'to be rescheduled now'.
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*
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* On UP this means the setting of the need_resched flag, on SMP it
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* might also involve a cross-CPU call to trigger the scheduler on
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* the target CPU.
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*/
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#ifdef CONFIG_SMP
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#ifndef tsk_is_polling
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#define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
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#endif
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void resched_task(struct task_struct *p)
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{
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int cpu;
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assert_raw_spin_locked(&task_rq(p)->lock);
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if (test_tsk_need_resched(p))
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return;
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set_tsk_need_resched(p);
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cpu = task_cpu(p);
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if (cpu == smp_processor_id())
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return;
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/* NEED_RESCHED must be visible before we test polling */
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smp_mb();
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if (!tsk_is_polling(p))
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smp_send_reschedule(cpu);
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}
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void resched_cpu(int cpu)
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{
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struct rq *rq = cpu_rq(cpu);
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unsigned long flags;
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if (!raw_spin_trylock_irqsave(&rq->lock, flags))
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return;
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resched_task(cpu_curr(cpu));
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raw_spin_unlock_irqrestore(&rq->lock, flags);
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}
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|
|
#ifdef CONFIG_NO_HZ
|
|
/*
|
|
* In the semi idle case, use the nearest busy cpu for migrating timers
|
|
* from an idle cpu. This is good for power-savings.
|
|
*
|
|
* We don't do similar optimization for completely idle system, as
|
|
* selecting an idle cpu will add more delays to the timers than intended
|
|
* (as that cpu's timer base may not be uptodate wrt jiffies etc).
|
|
*/
|
|
int get_nohz_timer_target(void)
|
|
{
|
|
int cpu = smp_processor_id();
|
|
int i;
|
|
struct sched_domain *sd;
|
|
|
|
rcu_read_lock();
|
|
for_each_domain(cpu, sd) {
|
|
for_each_cpu(i, sched_domain_span(sd)) {
|
|
if (!idle_cpu(i)) {
|
|
cpu = i;
|
|
goto unlock;
|
|
}
|
|
}
|
|
}
|
|
unlock:
|
|
rcu_read_unlock();
|
|
return cpu;
|
|
}
|
|
/*
|
|
* When add_timer_on() enqueues a timer into the timer wheel of an
|
|
* idle CPU then this timer might expire before the next timer event
|
|
* which is scheduled to wake up that CPU. In case of a completely
|
|
* idle system the next event might even be infinite time into the
|
|
* future. wake_up_idle_cpu() ensures that the CPU is woken up and
|
|
* leaves the inner idle loop so the newly added timer is taken into
|
|
* account when the CPU goes back to idle and evaluates the timer
|
|
* wheel for the next timer event.
|
|
*/
|
|
void wake_up_idle_cpu(int cpu)
|
|
{
|
|
struct rq *rq = cpu_rq(cpu);
|
|
|
|
if (cpu == smp_processor_id())
|
|
return;
|
|
|
|
/*
|
|
* This is safe, as this function is called with the timer
|
|
* wheel base lock of (cpu) held. When the CPU is on the way
|
|
* to idle and has not yet set rq->curr to idle then it will
|
|
* be serialized on the timer wheel base lock and take the new
|
|
* timer into account automatically.
|
|
*/
|
|
if (rq->curr != rq->idle)
|
|
return;
|
|
|
|
/*
|
|
* We can set TIF_RESCHED on the idle task of the other CPU
|
|
* lockless. The worst case is that the other CPU runs the
|
|
* idle task through an additional NOOP schedule()
|
|
*/
|
|
set_tsk_need_resched(rq->idle);
|
|
|
|
/* NEED_RESCHED must be visible before we test polling */
|
|
smp_mb();
|
|
if (!tsk_is_polling(rq->idle))
|
|
smp_send_reschedule(cpu);
|
|
}
|
|
|
|
static inline bool got_nohz_idle_kick(void)
|
|
{
|
|
int cpu = smp_processor_id();
|
|
return idle_cpu(cpu) && test_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu));
|
|
}
|
|
|
|
#else /* CONFIG_NO_HZ */
|
|
|
|
static inline bool got_nohz_idle_kick(void)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
#endif /* CONFIG_NO_HZ */
|
|
|
|
void sched_avg_update(struct rq *rq)
|
|
{
|
|
s64 period = sched_avg_period();
|
|
|
|
while ((s64)(rq->clock - rq->age_stamp) > period) {
|
|
/*
|
|
* Inline assembly required to prevent the compiler
|
|
* optimising this loop into a divmod call.
|
|
* See __iter_div_u64_rem() for another example of this.
|
|
*/
|
|
asm("" : "+rm" (rq->age_stamp));
|
|
rq->age_stamp += period;
|
|
rq->rt_avg /= 2;
|
|
}
|
|
}
|
|
|
|
#else /* !CONFIG_SMP */
|
|
void resched_task(struct task_struct *p)
|
|
{
|
|
assert_raw_spin_locked(&task_rq(p)->lock);
|
|
set_tsk_need_resched(p);
|
|
}
|
|
#endif /* CONFIG_SMP */
|
|
|
|
#if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \
|
|
(defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH)))
|
|
/*
|
|
* Iterate task_group tree rooted at *from, calling @down when first entering a
|
|
* node and @up when leaving it for the final time.
|
|
*
|
|
* Caller must hold rcu_lock or sufficient equivalent.
|
|
*/
|
|
int walk_tg_tree_from(struct task_group *from,
|
|
tg_visitor down, tg_visitor up, void *data)
|
|
{
|
|
struct task_group *parent, *child;
|
|
int ret;
|
|
|
|
parent = from;
|
|
|
|
down:
|
|
ret = (*down)(parent, data);
|
|
if (ret)
|
|
goto out;
|
|
list_for_each_entry_rcu(child, &parent->children, siblings) {
|
|
parent = child;
|
|
goto down;
|
|
|
|
up:
|
|
continue;
|
|
}
|
|
ret = (*up)(parent, data);
|
|
if (ret || parent == from)
|
|
goto out;
|
|
|
|
child = parent;
|
|
parent = parent->parent;
|
|
if (parent)
|
|
goto up;
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
int tg_nop(struct task_group *tg, void *data)
|
|
{
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
static void set_load_weight(struct task_struct *p)
|
|
{
|
|
int prio = p->static_prio - MAX_RT_PRIO;
|
|
struct load_weight *load = &p->se.load;
|
|
|
|
/*
|
|
* SCHED_IDLE tasks get minimal weight:
|
|
*/
|
|
if (p->policy == SCHED_IDLE) {
|
|
load->weight = scale_load(WEIGHT_IDLEPRIO);
|
|
load->inv_weight = WMULT_IDLEPRIO;
|
|
return;
|
|
}
|
|
|
|
load->weight = scale_load(prio_to_weight[prio]);
|
|
load->inv_weight = prio_to_wmult[prio];
|
|
}
|
|
|
|
static void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
|
|
{
|
|
update_rq_clock(rq);
|
|
sched_info_queued(p);
|
|
p->sched_class->enqueue_task(rq, p, flags);
|
|
}
|
|
|
|
static void dequeue_task(struct rq *rq, struct task_struct *p, int flags)
|
|
{
|
|
update_rq_clock(rq);
|
|
sched_info_dequeued(p);
|
|
p->sched_class->dequeue_task(rq, p, flags);
|
|
}
|
|
|
|
void activate_task(struct rq *rq, struct task_struct *p, int flags)
|
|
{
|
|
if (task_contributes_to_load(p))
|
|
rq->nr_uninterruptible--;
|
|
|
|
enqueue_task(rq, p, flags);
|
|
}
|
|
|
|
void deactivate_task(struct rq *rq, struct task_struct *p, int flags)
|
|
{
|
|
if (task_contributes_to_load(p))
|
|
rq->nr_uninterruptible++;
|
|
|
|
dequeue_task(rq, p, flags);
|
|
}
|
|
|
|
#ifdef CONFIG_IRQ_TIME_ACCOUNTING
|
|
|
|
/*
|
|
* There are no locks covering percpu hardirq/softirq time.
|
|
* They are only modified in account_system_vtime, on corresponding CPU
|
|
* with interrupts disabled. So, writes are safe.
|
|
* They are read and saved off onto struct rq in update_rq_clock().
|
|
* This may result in other CPU reading this CPU's irq time and can
|
|
* race with irq/account_system_vtime on this CPU. We would either get old
|
|
* or new value with a side effect of accounting a slice of irq time to wrong
|
|
* task when irq is in progress while we read rq->clock. That is a worthy
|
|
* compromise in place of having locks on each irq in account_system_time.
|
|
*/
|
|
static DEFINE_PER_CPU(u64, cpu_hardirq_time);
|
|
static DEFINE_PER_CPU(u64, cpu_softirq_time);
|
|
|
|
static DEFINE_PER_CPU(u64, irq_start_time);
|
|
static int sched_clock_irqtime;
|
|
|
|
void enable_sched_clock_irqtime(void)
|
|
{
|
|
sched_clock_irqtime = 1;
|
|
}
|
|
|
|
void disable_sched_clock_irqtime(void)
|
|
{
|
|
sched_clock_irqtime = 0;
|
|
}
|
|
|
|
#ifndef CONFIG_64BIT
|
|
static DEFINE_PER_CPU(seqcount_t, irq_time_seq);
|
|
|
|
static inline void irq_time_write_begin(void)
|
|
{
|
|
__this_cpu_inc(irq_time_seq.sequence);
|
|
smp_wmb();
|
|
}
|
|
|
|
static inline void irq_time_write_end(void)
|
|
{
|
|
smp_wmb();
|
|
__this_cpu_inc(irq_time_seq.sequence);
|
|
}
|
|
|
|
static inline u64 irq_time_read(int cpu)
|
|
{
|
|
u64 irq_time;
|
|
unsigned seq;
|
|
|
|
do {
|
|
seq = read_seqcount_begin(&per_cpu(irq_time_seq, cpu));
|
|
irq_time = per_cpu(cpu_softirq_time, cpu) +
|
|
per_cpu(cpu_hardirq_time, cpu);
|
|
} while (read_seqcount_retry(&per_cpu(irq_time_seq, cpu), seq));
|
|
|
|
return irq_time;
|
|
}
|
|
#else /* CONFIG_64BIT */
|
|
static inline void irq_time_write_begin(void)
|
|
{
|
|
}
|
|
|
|
static inline void irq_time_write_end(void)
|
|
{
|
|
}
|
|
|
|
static inline u64 irq_time_read(int cpu)
|
|
{
|
|
return per_cpu(cpu_softirq_time, cpu) + per_cpu(cpu_hardirq_time, cpu);
|
|
}
|
|
#endif /* CONFIG_64BIT */
|
|
|
|
/*
|
|
* Called before incrementing preempt_count on {soft,}irq_enter
|
|
* and before decrementing preempt_count on {soft,}irq_exit.
|
|
*/
|
|
void account_system_vtime(struct task_struct *curr)
|
|
{
|
|
unsigned long flags;
|
|
s64 delta;
|
|
int cpu;
|
|
|
|
if (!sched_clock_irqtime)
|
|
return;
|
|
|
|
local_irq_save(flags);
|
|
|
|
cpu = smp_processor_id();
|
|
delta = sched_clock_cpu(cpu) - __this_cpu_read(irq_start_time);
|
|
__this_cpu_add(irq_start_time, delta);
|
|
|
|
irq_time_write_begin();
|
|
/*
|
|
* We do not account for softirq time from ksoftirqd here.
|
|
* We want to continue accounting softirq time to ksoftirqd thread
|
|
* in that case, so as not to confuse scheduler with a special task
|
|
* that do not consume any time, but still wants to run.
|
|
*/
|
|
if (hardirq_count())
|
|
__this_cpu_add(cpu_hardirq_time, delta);
|
|
else if (in_serving_softirq() && curr != this_cpu_ksoftirqd())
|
|
__this_cpu_add(cpu_softirq_time, delta);
|
|
|
|
irq_time_write_end();
|
|
local_irq_restore(flags);
|
|
}
|
|
EXPORT_SYMBOL_GPL(account_system_vtime);
|
|
|
|
#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
|
|
|
|
#ifdef CONFIG_PARAVIRT
|
|
static inline u64 steal_ticks(u64 steal)
|
|
{
|
|
if (unlikely(steal > NSEC_PER_SEC))
|
|
return div_u64(steal, TICK_NSEC);
|
|
|
|
return __iter_div_u64_rem(steal, TICK_NSEC, &steal);
|
|
}
|
|
#endif
|
|
|
|
static void update_rq_clock_task(struct rq *rq, s64 delta)
|
|
{
|
|
/*
|
|
* In theory, the compile should just see 0 here, and optimize out the call
|
|
* to sched_rt_avg_update. But I don't trust it...
|
|
*/
|
|
#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
|
|
s64 steal = 0, irq_delta = 0;
|
|
#endif
|
|
#ifdef CONFIG_IRQ_TIME_ACCOUNTING
|
|
irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time;
|
|
|
|
/*
|
|
* Since irq_time is only updated on {soft,}irq_exit, we might run into
|
|
* this case when a previous update_rq_clock() happened inside a
|
|
* {soft,}irq region.
|
|
*
|
|
* When this happens, we stop ->clock_task and only update the
|
|
* prev_irq_time stamp to account for the part that fit, so that a next
|
|
* update will consume the rest. This ensures ->clock_task is
|
|
* monotonic.
|
|
*
|
|
* It does however cause some slight miss-attribution of {soft,}irq
|
|
* time, a more accurate solution would be to update the irq_time using
|
|
* the current rq->clock timestamp, except that would require using
|
|
* atomic ops.
|
|
*/
|
|
if (irq_delta > delta)
|
|
irq_delta = delta;
|
|
|
|
rq->prev_irq_time += irq_delta;
|
|
delta -= irq_delta;
|
|
#endif
|
|
#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
|
|
if (static_key_false((¶virt_steal_rq_enabled))) {
|
|
u64 st;
|
|
|
|
steal = paravirt_steal_clock(cpu_of(rq));
|
|
steal -= rq->prev_steal_time_rq;
|
|
|
|
if (unlikely(steal > delta))
|
|
steal = delta;
|
|
|
|
st = steal_ticks(steal);
|
|
steal = st * TICK_NSEC;
|
|
|
|
rq->prev_steal_time_rq += steal;
|
|
|
|
delta -= steal;
|
|
}
|
|
#endif
|
|
|
|
rq->clock_task += delta;
|
|
|
|
#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
|
|
if ((irq_delta + steal) && sched_feat(NONTASK_POWER))
|
|
sched_rt_avg_update(rq, irq_delta + steal);
|
|
#endif
|
|
}
|
|
|
|
#ifdef CONFIG_IRQ_TIME_ACCOUNTING
|
|
static int irqtime_account_hi_update(void)
|
|
{
|
|
u64 *cpustat = kcpustat_this_cpu->cpustat;
|
|
unsigned long flags;
|
|
u64 latest_ns;
|
|
int ret = 0;
|
|
|
|
local_irq_save(flags);
|
|
latest_ns = this_cpu_read(cpu_hardirq_time);
|
|
if (nsecs_to_cputime64(latest_ns) > cpustat[CPUTIME_IRQ])
|
|
ret = 1;
|
|
local_irq_restore(flags);
|
|
return ret;
|
|
}
|
|
|
|
static int irqtime_account_si_update(void)
|
|
{
|
|
u64 *cpustat = kcpustat_this_cpu->cpustat;
|
|
unsigned long flags;
|
|
u64 latest_ns;
|
|
int ret = 0;
|
|
|
|
local_irq_save(flags);
|
|
latest_ns = this_cpu_read(cpu_softirq_time);
|
|
if (nsecs_to_cputime64(latest_ns) > cpustat[CPUTIME_SOFTIRQ])
|
|
ret = 1;
|
|
local_irq_restore(flags);
|
|
return ret;
|
|
}
|
|
|
|
#else /* CONFIG_IRQ_TIME_ACCOUNTING */
|
|
|
|
#define sched_clock_irqtime (0)
|
|
|
|
#endif
|
|
|
|
void sched_set_stop_task(int cpu, struct task_struct *stop)
|
|
{
|
|
struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
|
|
struct task_struct *old_stop = cpu_rq(cpu)->stop;
|
|
|
|
if (stop) {
|
|
/*
|
|
* Make it appear like a SCHED_FIFO task, its something
|
|
* userspace knows about and won't get confused about.
|
|
*
|
|
* Also, it will make PI more or less work without too
|
|
* much confusion -- but then, stop work should not
|
|
* rely on PI working anyway.
|
|
*/
|
|
sched_setscheduler_nocheck(stop, SCHED_FIFO, ¶m);
|
|
|
|
stop->sched_class = &stop_sched_class;
|
|
}
|
|
|
|
cpu_rq(cpu)->stop = stop;
|
|
|
|
if (old_stop) {
|
|
/*
|
|
* Reset it back to a normal scheduling class so that
|
|
* it can die in pieces.
|
|
*/
|
|
old_stop->sched_class = &rt_sched_class;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* __normal_prio - return the priority that is based on the static prio
|
|
*/
|
|
static inline int __normal_prio(struct task_struct *p)
|
|
{
|
|
return p->static_prio;
|
|
}
|
|
|
|
/*
|
|
* Calculate the expected normal priority: i.e. priority
|
|
* without taking RT-inheritance into account. Might be
|
|
* boosted by interactivity modifiers. Changes upon fork,
|
|
* setprio syscalls, and whenever the interactivity
|
|
* estimator recalculates.
|
|
*/
|
|
static inline int normal_prio(struct task_struct *p)
|
|
{
|
|
int prio;
|
|
|
|
if (task_has_rt_policy(p))
|
|
prio = MAX_RT_PRIO-1 - p->rt_priority;
|
|
else
|
|
prio = __normal_prio(p);
|
|
return prio;
|
|
}
|
|
|
|
/*
|
|
* Calculate the current priority, i.e. the priority
|
|
* taken into account by the scheduler. This value might
|
|
* be boosted by RT tasks, or might be boosted by
|
|
* interactivity modifiers. Will be RT if the task got
|
|
* RT-boosted. If not then it returns p->normal_prio.
|
|
*/
|
|
static int effective_prio(struct task_struct *p)
|
|
{
|
|
p->normal_prio = normal_prio(p);
|
|
/*
|
|
* If we are RT tasks or we were boosted to RT priority,
|
|
* keep the priority unchanged. Otherwise, update priority
|
|
* to the normal priority:
|
|
*/
|
|
if (!rt_prio(p->prio))
|
|
return p->normal_prio;
|
|
return p->prio;
|
|
}
|
|
|
|
/**
|
|
* task_curr - is this task currently executing on a CPU?
|
|
* @p: the task in question.
|
|
*/
|
|
inline int task_curr(const struct task_struct *p)
|
|
{
|
|
return cpu_curr(task_cpu(p)) == p;
|
|
}
|
|
|
|
static inline void check_class_changed(struct rq *rq, struct task_struct *p,
|
|
const struct sched_class *prev_class,
|
|
int oldprio)
|
|
{
|
|
if (prev_class != p->sched_class) {
|
|
if (prev_class->switched_from)
|
|
prev_class->switched_from(rq, p);
|
|
p->sched_class->switched_to(rq, p);
|
|
} else if (oldprio != p->prio)
|
|
p->sched_class->prio_changed(rq, p, oldprio);
|
|
}
|
|
|
|
void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags)
|
|
{
|
|
const struct sched_class *class;
|
|
|
|
if (p->sched_class == rq->curr->sched_class) {
|
|
rq->curr->sched_class->check_preempt_curr(rq, p, flags);
|
|
} else {
|
|
for_each_class(class) {
|
|
if (class == rq->curr->sched_class)
|
|
break;
|
|
if (class == p->sched_class) {
|
|
resched_task(rq->curr);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* A queue event has occurred, and we're going to schedule. In
|
|
* this case, we can save a useless back to back clock update.
|
|
*/
|
|
if (rq->curr->on_rq && test_tsk_need_resched(rq->curr))
|
|
rq->skip_clock_update = 1;
|
|
}
|
|
|
|
#ifdef CONFIG_SMP
|
|
void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
|
|
{
|
|
#ifdef CONFIG_SCHED_DEBUG
|
|
/*
|
|
* We should never call set_task_cpu() on a blocked task,
|
|
* ttwu() will sort out the placement.
|
|
*/
|
|
WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING &&
|
|
!(task_thread_info(p)->preempt_count & PREEMPT_ACTIVE));
|
|
|
|
#ifdef CONFIG_LOCKDEP
|
|
/*
|
|
* The caller should hold either p->pi_lock or rq->lock, when changing
|
|
* a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
|
|
*
|
|
* sched_move_task() holds both and thus holding either pins the cgroup,
|
|
* see task_group().
|
|
*
|
|
* Furthermore, all task_rq users should acquire both locks, see
|
|
* task_rq_lock().
|
|
*/
|
|
WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) ||
|
|
lockdep_is_held(&task_rq(p)->lock)));
|
|
#endif
|
|
#endif
|
|
|
|
trace_sched_migrate_task(p, new_cpu);
|
|
|
|
if (task_cpu(p) != new_cpu) {
|
|
p->se.nr_migrations++;
|
|
perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, NULL, 0);
|
|
}
|
|
|
|
__set_task_cpu(p, new_cpu);
|
|
}
|
|
|
|
struct migration_arg {
|
|
struct task_struct *task;
|
|
int dest_cpu;
|
|
};
|
|
|
|
static int migration_cpu_stop(void *data);
|
|
|
|
/*
|
|
* wait_task_inactive - wait for a thread to unschedule.
|
|
*
|
|
* If @match_state is nonzero, it's the @p->state value just checked and
|
|
* not expected to change. If it changes, i.e. @p might have woken up,
|
|
* then return zero. When we succeed in waiting for @p to be off its CPU,
|
|
* we return a positive number (its total switch count). If a second call
|
|
* a short while later returns the same number, the caller can be sure that
|
|
* @p has remained unscheduled the whole time.
|
|
*
|
|
* The caller must ensure that the task *will* unschedule sometime soon,
|
|
* else this function might spin for a *long* time. This function can't
|
|
* be called with interrupts off, or it may introduce deadlock with
|
|
* smp_call_function() if an IPI is sent by the same process we are
|
|
* waiting to become inactive.
|
|
*/
|
|
unsigned long wait_task_inactive(struct task_struct *p, long match_state)
|
|
{
|
|
unsigned long flags;
|
|
int running, on_rq;
|
|
unsigned long ncsw;
|
|
struct rq *rq;
|
|
|
|
for (;;) {
|
|
/*
|
|
* We do the initial early heuristics without holding
|
|
* any task-queue locks at all. We'll only try to get
|
|
* the runqueue lock when things look like they will
|
|
* work out!
|
|
*/
|
|
rq = task_rq(p);
|
|
|
|
/*
|
|
* If the task is actively running on another CPU
|
|
* still, just relax and busy-wait without holding
|
|
* any locks.
|
|
*
|
|
* NOTE! Since we don't hold any locks, it's not
|
|
* even sure that "rq" stays as the right runqueue!
|
|
* But we don't care, since "task_running()" will
|
|
* return false if the runqueue has changed and p
|
|
* is actually now running somewhere else!
|
|
*/
|
|
while (task_running(rq, p)) {
|
|
if (match_state && unlikely(p->state != match_state))
|
|
return 0;
|
|
cpu_relax();
|
|
}
|
|
|
|
/*
|
|
* Ok, time to look more closely! We need the rq
|
|
* lock now, to be *sure*. If we're wrong, we'll
|
|
* just go back and repeat.
|
|
*/
|
|
rq = task_rq_lock(p, &flags);
|
|
trace_sched_wait_task(p);
|
|
running = task_running(rq, p);
|
|
on_rq = p->on_rq;
|
|
ncsw = 0;
|
|
if (!match_state || p->state == match_state)
|
|
ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
|
|
task_rq_unlock(rq, p, &flags);
|
|
|
|
/*
|
|
* If it changed from the expected state, bail out now.
|
|
*/
|
|
if (unlikely(!ncsw))
|
|
break;
|
|
|
|
/*
|
|
* Was it really running after all now that we
|
|
* checked with the proper locks actually held?
|
|
*
|
|
* Oops. Go back and try again..
|
|
*/
|
|
if (unlikely(running)) {
|
|
cpu_relax();
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* It's not enough that it's not actively running,
|
|
* it must be off the runqueue _entirely_, and not
|
|
* preempted!
|
|
*
|
|
* So if it was still runnable (but just not actively
|
|
* running right now), it's preempted, and we should
|
|
* yield - it could be a while.
|
|
*/
|
|
if (unlikely(on_rq)) {
|
|
ktime_t to = ktime_set(0, NSEC_PER_SEC/HZ);
|
|
|
|
set_current_state(TASK_UNINTERRUPTIBLE);
|
|
schedule_hrtimeout(&to, HRTIMER_MODE_REL);
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* Ahh, all good. It wasn't running, and it wasn't
|
|
* runnable, which means that it will never become
|
|
* running in the future either. We're all done!
|
|
*/
|
|
break;
|
|
}
|
|
|
|
return ncsw;
|
|
}
|
|
|
|
/***
|
|
* kick_process - kick a running thread to enter/exit the kernel
|
|
* @p: the to-be-kicked thread
|
|
*
|
|
* Cause a process which is running on another CPU to enter
|
|
* kernel-mode, without any delay. (to get signals handled.)
|
|
*
|
|
* NOTE: this function doesn't have to take the runqueue lock,
|
|
* because all it wants to ensure is that the remote task enters
|
|
* the kernel. If the IPI races and the task has been migrated
|
|
* to another CPU then no harm is done and the purpose has been
|
|
* achieved as well.
|
|
*/
|
|
void kick_process(struct task_struct *p)
|
|
{
|
|
int cpu;
|
|
|
|
preempt_disable();
|
|
cpu = task_cpu(p);
|
|
if ((cpu != smp_processor_id()) && task_curr(p))
|
|
smp_send_reschedule(cpu);
|
|
preempt_enable();
|
|
}
|
|
EXPORT_SYMBOL_GPL(kick_process);
|
|
#endif /* CONFIG_SMP */
|
|
|
|
#ifdef CONFIG_SMP
|
|
/*
|
|
* ->cpus_allowed is protected by both rq->lock and p->pi_lock
|
|
*/
|
|
static int select_fallback_rq(int cpu, struct task_struct *p)
|
|
{
|
|
const struct cpumask *nodemask = cpumask_of_node(cpu_to_node(cpu));
|
|
enum { cpuset, possible, fail } state = cpuset;
|
|
int dest_cpu;
|
|
|
|
/* Look for allowed, online CPU in same node. */
|
|
for_each_cpu(dest_cpu, nodemask) {
|
|
if (!cpu_online(dest_cpu))
|
|
continue;
|
|
if (!cpu_active(dest_cpu))
|
|
continue;
|
|
if (cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p)))
|
|
return dest_cpu;
|
|
}
|
|
|
|
for (;;) {
|
|
/* Any allowed, online CPU? */
|
|
for_each_cpu(dest_cpu, tsk_cpus_allowed(p)) {
|
|
if (!cpu_online(dest_cpu))
|
|
continue;
|
|
if (!cpu_active(dest_cpu))
|
|
continue;
|
|
goto out;
|
|
}
|
|
|
|
switch (state) {
|
|
case cpuset:
|
|
/* No more Mr. Nice Guy. */
|
|
cpuset_cpus_allowed_fallback(p);
|
|
state = possible;
|
|
break;
|
|
|
|
case possible:
|
|
do_set_cpus_allowed(p, cpu_possible_mask);
|
|
state = fail;
|
|
break;
|
|
|
|
case fail:
|
|
BUG();
|
|
break;
|
|
}
|
|
}
|
|
|
|
out:
|
|
if (state != cpuset) {
|
|
/*
|
|
* Don't tell them about moving exiting tasks or
|
|
* kernel threads (both mm NULL), since they never
|
|
* leave kernel.
|
|
*/
|
|
if (p->mm && printk_ratelimit()) {
|
|
printk_sched("process %d (%s) no longer affine to cpu%d\n",
|
|
task_pid_nr(p), p->comm, cpu);
|
|
}
|
|
}
|
|
|
|
return dest_cpu;
|
|
}
|
|
|
|
/*
|
|
* The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable.
|
|
*/
|
|
static inline
|
|
int select_task_rq(struct task_struct *p, int sd_flags, int wake_flags)
|
|
{
|
|
int cpu = p->sched_class->select_task_rq(p, sd_flags, wake_flags);
|
|
|
|
/*
|
|
* In order not to call set_task_cpu() on a blocking task we need
|
|
* to rely on ttwu() to place the task on a valid ->cpus_allowed
|
|
* cpu.
|
|
*
|
|
* Since this is common to all placement strategies, this lives here.
|
|
*
|
|
* [ this allows ->select_task() to simply return task_cpu(p) and
|
|
* not worry about this generic constraint ]
|
|
*/
|
|
if (unlikely(!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)) ||
|
|
!cpu_online(cpu)))
|
|
cpu = select_fallback_rq(task_cpu(p), p);
|
|
|
|
return cpu;
|
|
}
|
|
|
|
static void update_avg(u64 *avg, u64 sample)
|
|
{
|
|
s64 diff = sample - *avg;
|
|
*avg += diff >> 3;
|
|
}
|
|
#endif
|
|
|
|
static void
|
|
ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
|
|
{
|
|
#ifdef CONFIG_SCHEDSTATS
|
|
struct rq *rq = this_rq();
|
|
|
|
#ifdef CONFIG_SMP
|
|
int this_cpu = smp_processor_id();
|
|
|
|
if (cpu == this_cpu) {
|
|
schedstat_inc(rq, ttwu_local);
|
|
schedstat_inc(p, se.statistics.nr_wakeups_local);
|
|
} else {
|
|
struct sched_domain *sd;
|
|
|
|
schedstat_inc(p, se.statistics.nr_wakeups_remote);
|
|
rcu_read_lock();
|
|
for_each_domain(this_cpu, sd) {
|
|
if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
|
|
schedstat_inc(sd, ttwu_wake_remote);
|
|
break;
|
|
}
|
|
}
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
if (wake_flags & WF_MIGRATED)
|
|
schedstat_inc(p, se.statistics.nr_wakeups_migrate);
|
|
|
|
#endif /* CONFIG_SMP */
|
|
|
|
schedstat_inc(rq, ttwu_count);
|
|
schedstat_inc(p, se.statistics.nr_wakeups);
|
|
|
|
if (wake_flags & WF_SYNC)
|
|
schedstat_inc(p, se.statistics.nr_wakeups_sync);
|
|
|
|
#endif /* CONFIG_SCHEDSTATS */
|
|
}
|
|
|
|
static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags)
|
|
{
|
|
activate_task(rq, p, en_flags);
|
|
p->on_rq = 1;
|
|
|
|
/* if a worker is waking up, notify workqueue */
|
|
if (p->flags & PF_WQ_WORKER)
|
|
wq_worker_waking_up(p, cpu_of(rq));
|
|
}
|
|
|
|
/*
|
|
* Mark the task runnable and perform wakeup-preemption.
|
|
*/
|
|
static void
|
|
ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags)
|
|
{
|
|
trace_sched_wakeup(p, true);
|
|
check_preempt_curr(rq, p, wake_flags);
|
|
|
|
p->state = TASK_RUNNING;
|
|
#ifdef CONFIG_SMP
|
|
if (p->sched_class->task_woken)
|
|
p->sched_class->task_woken(rq, p);
|
|
|
|
if (rq->idle_stamp) {
|
|
u64 delta = rq->clock - rq->idle_stamp;
|
|
u64 max = 2*sysctl_sched_migration_cost;
|
|
|
|
if (delta > max)
|
|
rq->avg_idle = max;
|
|
else
|
|
update_avg(&rq->avg_idle, delta);
|
|
rq->idle_stamp = 0;
|
|
}
|
|
#endif
|
|
}
|
|
|
|
static void
|
|
ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags)
|
|
{
|
|
#ifdef CONFIG_SMP
|
|
if (p->sched_contributes_to_load)
|
|
rq->nr_uninterruptible--;
|
|
#endif
|
|
|
|
ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING);
|
|
ttwu_do_wakeup(rq, p, wake_flags);
|
|
}
|
|
|
|
/*
|
|
* Called in case the task @p isn't fully descheduled from its runqueue,
|
|
* in this case we must do a remote wakeup. Its a 'light' wakeup though,
|
|
* since all we need to do is flip p->state to TASK_RUNNING, since
|
|
* the task is still ->on_rq.
|
|
*/
|
|
static int ttwu_remote(struct task_struct *p, int wake_flags)
|
|
{
|
|
struct rq *rq;
|
|
int ret = 0;
|
|
|
|
rq = __task_rq_lock(p);
|
|
if (p->on_rq) {
|
|
ttwu_do_wakeup(rq, p, wake_flags);
|
|
ret = 1;
|
|
}
|
|
__task_rq_unlock(rq);
|
|
|
|
return ret;
|
|
}
|
|
|
|
#ifdef CONFIG_SMP
|
|
static void sched_ttwu_pending(void)
|
|
{
|
|
struct rq *rq = this_rq();
|
|
struct llist_node *llist = llist_del_all(&rq->wake_list);
|
|
struct task_struct *p;
|
|
|
|
raw_spin_lock(&rq->lock);
|
|
|
|
while (llist) {
|
|
p = llist_entry(llist, struct task_struct, wake_entry);
|
|
llist = llist_next(llist);
|
|
ttwu_do_activate(rq, p, 0);
|
|
}
|
|
|
|
raw_spin_unlock(&rq->lock);
|
|
}
|
|
|
|
void scheduler_ipi(void)
|
|
{
|
|
if (llist_empty(&this_rq()->wake_list) && !got_nohz_idle_kick())
|
|
return;
|
|
|
|
/*
|
|
* Not all reschedule IPI handlers call irq_enter/irq_exit, since
|
|
* traditionally all their work was done from the interrupt return
|
|
* path. Now that we actually do some work, we need to make sure
|
|
* we do call them.
|
|
*
|
|
* Some archs already do call them, luckily irq_enter/exit nest
|
|
* properly.
|
|
*
|
|
* Arguably we should visit all archs and update all handlers,
|
|
* however a fair share of IPIs are still resched only so this would
|
|
* somewhat pessimize the simple resched case.
|
|
*/
|
|
irq_enter();
|
|
sched_ttwu_pending();
|
|
|
|
/*
|
|
* Check if someone kicked us for doing the nohz idle load balance.
|
|
*/
|
|
if (unlikely(got_nohz_idle_kick() && !need_resched())) {
|
|
this_rq()->idle_balance = 1;
|
|
raise_softirq_irqoff(SCHED_SOFTIRQ);
|
|
}
|
|
irq_exit();
|
|
}
|
|
|
|
static void ttwu_queue_remote(struct task_struct *p, int cpu)
|
|
{
|
|
if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list))
|
|
smp_send_reschedule(cpu);
|
|
}
|
|
|
|
#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
|
|
static int ttwu_activate_remote(struct task_struct *p, int wake_flags)
|
|
{
|
|
struct rq *rq;
|
|
int ret = 0;
|
|
|
|
rq = __task_rq_lock(p);
|
|
if (p->on_cpu) {
|
|
ttwu_activate(rq, p, ENQUEUE_WAKEUP);
|
|
ttwu_do_wakeup(rq, p, wake_flags);
|
|
ret = 1;
|
|
}
|
|
__task_rq_unlock(rq);
|
|
|
|
return ret;
|
|
|
|
}
|
|
#endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
|
|
|
|
bool cpus_share_cache(int this_cpu, int that_cpu)
|
|
{
|
|
return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu);
|
|
}
|
|
#endif /* CONFIG_SMP */
|
|
|
|
static void ttwu_queue(struct task_struct *p, int cpu)
|
|
{
|
|
struct rq *rq = cpu_rq(cpu);
|
|
|
|
#if defined(CONFIG_SMP)
|
|
if (sched_feat(TTWU_QUEUE) && !cpus_share_cache(smp_processor_id(), cpu)) {
|
|
sched_clock_cpu(cpu); /* sync clocks x-cpu */
|
|
ttwu_queue_remote(p, cpu);
|
|
return;
|
|
}
|
|
#endif
|
|
|
|
raw_spin_lock(&rq->lock);
|
|
ttwu_do_activate(rq, p, 0);
|
|
raw_spin_unlock(&rq->lock);
|
|
}
|
|
|
|
/**
|
|
* try_to_wake_up - wake up a thread
|
|
* @p: the thread to be awakened
|
|
* @state: the mask of task states that can be woken
|
|
* @wake_flags: wake modifier flags (WF_*)
|
|
*
|
|
* Put it on the run-queue if it's not already there. The "current"
|
|
* thread is always on the run-queue (except when the actual
|
|
* re-schedule is in progress), and as such you're allowed to do
|
|
* the simpler "current->state = TASK_RUNNING" to mark yourself
|
|
* runnable without the overhead of this.
|
|
*
|
|
* Returns %true if @p was woken up, %false if it was already running
|
|
* or @state didn't match @p's state.
|
|
*/
|
|
static int
|
|
try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
|
|
{
|
|
unsigned long flags;
|
|
int cpu, success = 0;
|
|
|
|
smp_wmb();
|
|
raw_spin_lock_irqsave(&p->pi_lock, flags);
|
|
if (!(p->state & state))
|
|
goto out;
|
|
|
|
success = 1; /* we're going to change ->state */
|
|
cpu = task_cpu(p);
|
|
|
|
if (p->on_rq && ttwu_remote(p, wake_flags))
|
|
goto stat;
|
|
|
|
#ifdef CONFIG_SMP
|
|
/*
|
|
* If the owning (remote) cpu is still in the middle of schedule() with
|
|
* this task as prev, wait until its done referencing the task.
|
|
*/
|
|
while (p->on_cpu) {
|
|
#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
|
|
/*
|
|
* In case the architecture enables interrupts in
|
|
* context_switch(), we cannot busy wait, since that
|
|
* would lead to deadlocks when an interrupt hits and
|
|
* tries to wake up @prev. So bail and do a complete
|
|
* remote wakeup.
|
|
*/
|
|
if (ttwu_activate_remote(p, wake_flags))
|
|
goto stat;
|
|
#else
|
|
cpu_relax();
|
|
#endif
|
|
}
|
|
/*
|
|
* Pairs with the smp_wmb() in finish_lock_switch().
|
|
*/
|
|
smp_rmb();
|
|
|
|
p->sched_contributes_to_load = !!task_contributes_to_load(p);
|
|
p->state = TASK_WAKING;
|
|
|
|
if (p->sched_class->task_waking)
|
|
p->sched_class->task_waking(p);
|
|
|
|
cpu = select_task_rq(p, SD_BALANCE_WAKE, wake_flags);
|
|
if (task_cpu(p) != cpu) {
|
|
wake_flags |= WF_MIGRATED;
|
|
set_task_cpu(p, cpu);
|
|
}
|
|
#endif /* CONFIG_SMP */
|
|
|
|
ttwu_queue(p, cpu);
|
|
stat:
|
|
ttwu_stat(p, cpu, wake_flags);
|
|
out:
|
|
raw_spin_unlock_irqrestore(&p->pi_lock, flags);
|
|
|
|
return success;
|
|
}
|
|
|
|
/**
|
|
* try_to_wake_up_local - try to wake up a local task with rq lock held
|
|
* @p: the thread to be awakened
|
|
*
|
|
* Put @p on the run-queue if it's not already there. The caller must
|
|
* ensure that this_rq() is locked, @p is bound to this_rq() and not
|
|
* the current task.
|
|
*/
|
|
static void try_to_wake_up_local(struct task_struct *p)
|
|
{
|
|
struct rq *rq = task_rq(p);
|
|
|
|
BUG_ON(rq != this_rq());
|
|
BUG_ON(p == current);
|
|
lockdep_assert_held(&rq->lock);
|
|
|
|
if (!raw_spin_trylock(&p->pi_lock)) {
|
|
raw_spin_unlock(&rq->lock);
|
|
raw_spin_lock(&p->pi_lock);
|
|
raw_spin_lock(&rq->lock);
|
|
}
|
|
|
|
if (!(p->state & TASK_NORMAL))
|
|
goto out;
|
|
|
|
if (!p->on_rq)
|
|
ttwu_activate(rq, p, ENQUEUE_WAKEUP);
|
|
|
|
ttwu_do_wakeup(rq, p, 0);
|
|
ttwu_stat(p, smp_processor_id(), 0);
|
|
out:
|
|
raw_spin_unlock(&p->pi_lock);
|
|
}
|
|
|
|
/**
|
|
* wake_up_process - Wake up a specific process
|
|
* @p: The process to be woken up.
|
|
*
|
|
* Attempt to wake up the nominated process and move it to the set of runnable
|
|
* processes. Returns 1 if the process was woken up, 0 if it was already
|
|
* running.
|
|
*
|
|
* It may be assumed that this function implies a write memory barrier before
|
|
* changing the task state if and only if any tasks are woken up.
|
|
*/
|
|
int wake_up_process(struct task_struct *p)
|
|
{
|
|
return try_to_wake_up(p, TASK_ALL, 0);
|
|
}
|
|
EXPORT_SYMBOL(wake_up_process);
|
|
|
|
int wake_up_state(struct task_struct *p, unsigned int state)
|
|
{
|
|
return try_to_wake_up(p, state, 0);
|
|
}
|
|
|
|
/*
|
|
* Perform scheduler related setup for a newly forked process p.
|
|
* p is forked by current.
|
|
*
|
|
* __sched_fork() is basic setup used by init_idle() too:
|
|
*/
|
|
static void __sched_fork(struct task_struct *p)
|
|
{
|
|
p->on_rq = 0;
|
|
|
|
p->se.on_rq = 0;
|
|
p->se.exec_start = 0;
|
|
p->se.sum_exec_runtime = 0;
|
|
p->se.prev_sum_exec_runtime = 0;
|
|
p->se.nr_migrations = 0;
|
|
p->se.vruntime = 0;
|
|
INIT_LIST_HEAD(&p->se.group_node);
|
|
|
|
#ifdef CONFIG_SCHEDSTATS
|
|
memset(&p->se.statistics, 0, sizeof(p->se.statistics));
|
|
#endif
|
|
|
|
INIT_LIST_HEAD(&p->rt.run_list);
|
|
|
|
#ifdef CONFIG_PREEMPT_NOTIFIERS
|
|
INIT_HLIST_HEAD(&p->preempt_notifiers);
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* fork()/clone()-time setup:
|
|
*/
|
|
void sched_fork(struct task_struct *p)
|
|
{
|
|
unsigned long flags;
|
|
int cpu = get_cpu();
|
|
|
|
__sched_fork(p);
|
|
/*
|
|
* We mark the process as running here. This guarantees that
|
|
* nobody will actually run it, and a signal or other external
|
|
* event cannot wake it up and insert it on the runqueue either.
|
|
*/
|
|
p->state = TASK_RUNNING;
|
|
|
|
/*
|
|
* Make sure we do not leak PI boosting priority to the child.
|
|
*/
|
|
p->prio = current->normal_prio;
|
|
|
|
/*
|
|
* Revert to default priority/policy on fork if requested.
|
|
*/
|
|
if (unlikely(p->sched_reset_on_fork)) {
|
|
if (task_has_rt_policy(p)) {
|
|
p->policy = SCHED_NORMAL;
|
|
p->static_prio = NICE_TO_PRIO(0);
|
|
p->rt_priority = 0;
|
|
} else if (PRIO_TO_NICE(p->static_prio) < 0)
|
|
p->static_prio = NICE_TO_PRIO(0);
|
|
|
|
p->prio = p->normal_prio = __normal_prio(p);
|
|
set_load_weight(p);
|
|
|
|
/*
|
|
* We don't need the reset flag anymore after the fork. It has
|
|
* fulfilled its duty:
|
|
*/
|
|
p->sched_reset_on_fork = 0;
|
|
}
|
|
|
|
if (!rt_prio(p->prio))
|
|
p->sched_class = &fair_sched_class;
|
|
|
|
if (p->sched_class->task_fork)
|
|
p->sched_class->task_fork(p);
|
|
|
|
/*
|
|
* The child is not yet in the pid-hash so no cgroup attach races,
|
|
* and the cgroup is pinned to this child due to cgroup_fork()
|
|
* is ran before sched_fork().
|
|
*
|
|
* Silence PROVE_RCU.
|
|
*/
|
|
raw_spin_lock_irqsave(&p->pi_lock, flags);
|
|
set_task_cpu(p, cpu);
|
|
raw_spin_unlock_irqrestore(&p->pi_lock, flags);
|
|
|
|
#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
|
|
if (likely(sched_info_on()))
|
|
memset(&p->sched_info, 0, sizeof(p->sched_info));
|
|
#endif
|
|
#if defined(CONFIG_SMP)
|
|
p->on_cpu = 0;
|
|
#endif
|
|
#ifdef CONFIG_PREEMPT_COUNT
|
|
/* Want to start with kernel preemption disabled. */
|
|
task_thread_info(p)->preempt_count = 1;
|
|
#endif
|
|
#ifdef CONFIG_SMP
|
|
plist_node_init(&p->pushable_tasks, MAX_PRIO);
|
|
#endif
|
|
|
|
put_cpu();
|
|
}
|
|
|
|
/*
|
|
* wake_up_new_task - wake up a newly created task for the first time.
|
|
*
|
|
* This function will do some initial scheduler statistics housekeeping
|
|
* that must be done for every newly created context, then puts the task
|
|
* on the runqueue and wakes it.
|
|
*/
|
|
void wake_up_new_task(struct task_struct *p)
|
|
{
|
|
unsigned long flags;
|
|
struct rq *rq;
|
|
|
|
raw_spin_lock_irqsave(&p->pi_lock, flags);
|
|
#ifdef CONFIG_SMP
|
|
/*
|
|
* Fork balancing, do it here and not earlier because:
|
|
* - cpus_allowed can change in the fork path
|
|
* - any previously selected cpu might disappear through hotplug
|
|
*/
|
|
set_task_cpu(p, select_task_rq(p, SD_BALANCE_FORK, 0));
|
|
#endif
|
|
|
|
rq = __task_rq_lock(p);
|
|
activate_task(rq, p, 0);
|
|
p->on_rq = 1;
|
|
trace_sched_wakeup_new(p, true);
|
|
check_preempt_curr(rq, p, WF_FORK);
|
|
#ifdef CONFIG_SMP
|
|
if (p->sched_class->task_woken)
|
|
p->sched_class->task_woken(rq, p);
|
|
#endif
|
|
task_rq_unlock(rq, p, &flags);
|
|
}
|
|
|
|
#ifdef CONFIG_PREEMPT_NOTIFIERS
|
|
|
|
/**
|
|
* preempt_notifier_register - tell me when current is being preempted & rescheduled
|
|
* @notifier: notifier struct to register
|
|
*/
|
|
void preempt_notifier_register(struct preempt_notifier *notifier)
|
|
{
|
|
hlist_add_head(¬ifier->link, ¤t->preempt_notifiers);
|
|
}
|
|
EXPORT_SYMBOL_GPL(preempt_notifier_register);
|
|
|
|
/**
|
|
* preempt_notifier_unregister - no longer interested in preemption notifications
|
|
* @notifier: notifier struct to unregister
|
|
*
|
|
* This is safe to call from within a preemption notifier.
|
|
*/
|
|
void preempt_notifier_unregister(struct preempt_notifier *notifier)
|
|
{
|
|
hlist_del(¬ifier->link);
|
|
}
|
|
EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
|
|
|
|
static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
|
|
{
|
|
struct preempt_notifier *notifier;
|
|
struct hlist_node *node;
|
|
|
|
hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
|
|
notifier->ops->sched_in(notifier, raw_smp_processor_id());
|
|
}
|
|
|
|
static void
|
|
fire_sched_out_preempt_notifiers(struct task_struct *curr,
|
|
struct task_struct *next)
|
|
{
|
|
struct preempt_notifier *notifier;
|
|
struct hlist_node *node;
|
|
|
|
hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
|
|
notifier->ops->sched_out(notifier, next);
|
|
}
|
|
|
|
#else /* !CONFIG_PREEMPT_NOTIFIERS */
|
|
|
|
static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
|
|
{
|
|
}
|
|
|
|
static void
|
|
fire_sched_out_preempt_notifiers(struct task_struct *curr,
|
|
struct task_struct *next)
|
|
{
|
|
}
|
|
|
|
#endif /* CONFIG_PREEMPT_NOTIFIERS */
|
|
|
|
/**
|
|
* prepare_task_switch - prepare to switch tasks
|
|
* @rq: the runqueue preparing to switch
|
|
* @prev: the current task that is being switched out
|
|
* @next: the task we are going to switch to.
|
|
*
|
|
* This is called with the rq lock held and interrupts off. It must
|
|
* be paired with a subsequent finish_task_switch after the context
|
|
* switch.
|
|
*
|
|
* prepare_task_switch sets up locking and calls architecture specific
|
|
* hooks.
|
|
*/
|
|
static inline void
|
|
prepare_task_switch(struct rq *rq, struct task_struct *prev,
|
|
struct task_struct *next)
|
|
{
|
|
trace_sched_switch(prev, next);
|
|
sched_info_switch(prev, next);
|
|
perf_event_task_sched_out(prev, next);
|
|
fire_sched_out_preempt_notifiers(prev, next);
|
|
prepare_lock_switch(rq, next);
|
|
prepare_arch_switch(next);
|
|
}
|
|
|
|
/**
|
|
* finish_task_switch - clean up after a task-switch
|
|
* @rq: runqueue associated with task-switch
|
|
* @prev: the thread we just switched away from.
|
|
*
|
|
* finish_task_switch must be called after the context switch, paired
|
|
* with a prepare_task_switch call before the context switch.
|
|
* finish_task_switch will reconcile locking set up by prepare_task_switch,
|
|
* and do any other architecture-specific cleanup actions.
|
|
*
|
|
* Note that we may have delayed dropping an mm in context_switch(). If
|
|
* so, we finish that here outside of the runqueue lock. (Doing it
|
|
* with the lock held can cause deadlocks; see schedule() for
|
|
* details.)
|
|
*/
|
|
static void finish_task_switch(struct rq *rq, struct task_struct *prev)
|
|
__releases(rq->lock)
|
|
{
|
|
struct mm_struct *mm = rq->prev_mm;
|
|
long prev_state;
|
|
|
|
rq->prev_mm = NULL;
|
|
|
|
/*
|
|
* A task struct has one reference for the use as "current".
|
|
* If a task dies, then it sets TASK_DEAD in tsk->state and calls
|
|
* schedule one last time. The schedule call will never return, and
|
|
* the scheduled task must drop that reference.
|
|
* The test for TASK_DEAD must occur while the runqueue locks are
|
|
* still held, otherwise prev could be scheduled on another cpu, die
|
|
* there before we look at prev->state, and then the reference would
|
|
* be dropped twice.
|
|
* Manfred Spraul <manfred@colorfullife.com>
|
|
*/
|
|
prev_state = prev->state;
|
|
finish_arch_switch(prev);
|
|
#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
|
|
local_irq_disable();
|
|
#endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
|
|
perf_event_task_sched_in(prev, current);
|
|
#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
|
|
local_irq_enable();
|
|
#endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
|
|
finish_lock_switch(rq, prev);
|
|
finish_arch_post_lock_switch();
|
|
|
|
fire_sched_in_preempt_notifiers(current);
|
|
if (mm)
|
|
mmdrop(mm);
|
|
if (unlikely(prev_state == TASK_DEAD)) {
|
|
/*
|
|
* Remove function-return probe instances associated with this
|
|
* task and put them back on the free list.
|
|
*/
|
|
kprobe_flush_task(prev);
|
|
put_task_struct(prev);
|
|
}
|
|
}
|
|
|
|
#ifdef CONFIG_SMP
|
|
|
|
/* assumes rq->lock is held */
|
|
static inline void pre_schedule(struct rq *rq, struct task_struct *prev)
|
|
{
|
|
if (prev->sched_class->pre_schedule)
|
|
prev->sched_class->pre_schedule(rq, prev);
|
|
}
|
|
|
|
/* rq->lock is NOT held, but preemption is disabled */
|
|
static inline void post_schedule(struct rq *rq)
|
|
{
|
|
if (rq->post_schedule) {
|
|
unsigned long flags;
|
|
|
|
raw_spin_lock_irqsave(&rq->lock, flags);
|
|
if (rq->curr->sched_class->post_schedule)
|
|
rq->curr->sched_class->post_schedule(rq);
|
|
raw_spin_unlock_irqrestore(&rq->lock, flags);
|
|
|
|
rq->post_schedule = 0;
|
|
}
|
|
}
|
|
|
|
#else
|
|
|
|
static inline void pre_schedule(struct rq *rq, struct task_struct *p)
|
|
{
|
|
}
|
|
|
|
static inline void post_schedule(struct rq *rq)
|
|
{
|
|
}
|
|
|
|
#endif
|
|
|
|
/**
|
|
* schedule_tail - first thing a freshly forked thread must call.
|
|
* @prev: the thread we just switched away from.
|
|
*/
|
|
asmlinkage void schedule_tail(struct task_struct *prev)
|
|
__releases(rq->lock)
|
|
{
|
|
struct rq *rq = this_rq();
|
|
|
|
finish_task_switch(rq, prev);
|
|
|
|
/*
|
|
* FIXME: do we need to worry about rq being invalidated by the
|
|
* task_switch?
|
|
*/
|
|
post_schedule(rq);
|
|
|
|
#ifdef __ARCH_WANT_UNLOCKED_CTXSW
|
|
/* In this case, finish_task_switch does not reenable preemption */
|
|
preempt_enable();
|
|
#endif
|
|
if (current->set_child_tid)
|
|
put_user(task_pid_vnr(current), current->set_child_tid);
|
|
}
|
|
|
|
/*
|
|
* context_switch - switch to the new MM and the new
|
|
* thread's register state.
|
|
*/
|
|
static inline void
|
|
context_switch(struct rq *rq, struct task_struct *prev,
|
|
struct task_struct *next)
|
|
{
|
|
struct mm_struct *mm, *oldmm;
|
|
|
|
prepare_task_switch(rq, prev, next);
|
|
|
|
mm = next->mm;
|
|
oldmm = prev->active_mm;
|
|
/*
|
|
* For paravirt, this is coupled with an exit in switch_to to
|
|
* combine the page table reload and the switch backend into
|
|
* one hypercall.
|
|
*/
|
|
arch_start_context_switch(prev);
|
|
|
|
if (!mm) {
|
|
next->active_mm = oldmm;
|
|
atomic_inc(&oldmm->mm_count);
|
|
enter_lazy_tlb(oldmm, next);
|
|
} else
|
|
switch_mm(oldmm, mm, next);
|
|
|
|
if (!prev->mm) {
|
|
prev->active_mm = NULL;
|
|
rq->prev_mm = oldmm;
|
|
}
|
|
/*
|
|
* Since the runqueue lock will be released by the next
|
|
* task (which is an invalid locking op but in the case
|
|
* of the scheduler it's an obvious special-case), so we
|
|
* do an early lockdep release here:
|
|
*/
|
|
#ifndef __ARCH_WANT_UNLOCKED_CTXSW
|
|
spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
|
|
#endif
|
|
|
|
/* Here we just switch the register state and the stack. */
|
|
switch_to(prev, next, prev);
|
|
|
|
barrier();
|
|
/*
|
|
* this_rq must be evaluated again because prev may have moved
|
|
* CPUs since it called schedule(), thus the 'rq' on its stack
|
|
* frame will be invalid.
|
|
*/
|
|
finish_task_switch(this_rq(), prev);
|
|
}
|
|
|
|
/*
|
|
* nr_running, nr_uninterruptible and nr_context_switches:
|
|
*
|
|
* externally visible scheduler statistics: current number of runnable
|
|
* threads, current number of uninterruptible-sleeping threads, total
|
|
* number of context switches performed since bootup.
|
|
*/
|
|
unsigned long nr_running(void)
|
|
{
|
|
unsigned long i, sum = 0;
|
|
|
|
for_each_online_cpu(i)
|
|
sum += cpu_rq(i)->nr_running;
|
|
|
|
return sum;
|
|
}
|
|
|
|
unsigned long nr_uninterruptible(void)
|
|
{
|
|
unsigned long i, sum = 0;
|
|
|
|
for_each_possible_cpu(i)
|
|
sum += cpu_rq(i)->nr_uninterruptible;
|
|
|
|
/*
|
|
* Since we read the counters lockless, it might be slightly
|
|
* inaccurate. Do not allow it to go below zero though:
|
|
*/
|
|
if (unlikely((long)sum < 0))
|
|
sum = 0;
|
|
|
|
return sum;
|
|
}
|
|
|
|
unsigned long long nr_context_switches(void)
|
|
{
|
|
int i;
|
|
unsigned long long sum = 0;
|
|
|
|
for_each_possible_cpu(i)
|
|
sum += cpu_rq(i)->nr_switches;
|
|
|
|
return sum;
|
|
}
|
|
|
|
unsigned long nr_iowait(void)
|
|
{
|
|
unsigned long i, sum = 0;
|
|
|
|
for_each_possible_cpu(i)
|
|
sum += atomic_read(&cpu_rq(i)->nr_iowait);
|
|
|
|
return sum;
|
|
}
|
|
|
|
unsigned long nr_iowait_cpu(int cpu)
|
|
{
|
|
struct rq *this = cpu_rq(cpu);
|
|
return atomic_read(&this->nr_iowait);
|
|
}
|
|
|
|
unsigned long this_cpu_load(void)
|
|
{
|
|
struct rq *this = this_rq();
|
|
return this->cpu_load[0];
|
|
}
|
|
|
|
|
|
/*
|
|
* Global load-average calculations
|
|
*
|
|
* We take a distributed and async approach to calculating the global load-avg
|
|
* in order to minimize overhead.
|
|
*
|
|
* The global load average is an exponentially decaying average of nr_running +
|
|
* nr_uninterruptible.
|
|
*
|
|
* Once every LOAD_FREQ:
|
|
*
|
|
* nr_active = 0;
|
|
* for_each_possible_cpu(cpu)
|
|
* nr_active += cpu_of(cpu)->nr_running + cpu_of(cpu)->nr_uninterruptible;
|
|
*
|
|
* avenrun[n] = avenrun[0] * exp_n + nr_active * (1 - exp_n)
|
|
*
|
|
* Due to a number of reasons the above turns in the mess below:
|
|
*
|
|
* - for_each_possible_cpu() is prohibitively expensive on machines with
|
|
* serious number of cpus, therefore we need to take a distributed approach
|
|
* to calculating nr_active.
|
|
*
|
|
* \Sum_i x_i(t) = \Sum_i x_i(t) - x_i(t_0) | x_i(t_0) := 0
|
|
* = \Sum_i { \Sum_j=1 x_i(t_j) - x_i(t_j-1) }
|
|
*
|
|
* So assuming nr_active := 0 when we start out -- true per definition, we
|
|
* can simply take per-cpu deltas and fold those into a global accumulate
|
|
* to obtain the same result. See calc_load_fold_active().
|
|
*
|
|
* Furthermore, in order to avoid synchronizing all per-cpu delta folding
|
|
* across the machine, we assume 10 ticks is sufficient time for every
|
|
* cpu to have completed this task.
|
|
*
|
|
* This places an upper-bound on the IRQ-off latency of the machine. Then
|
|
* again, being late doesn't loose the delta, just wrecks the sample.
|
|
*
|
|
* - cpu_rq()->nr_uninterruptible isn't accurately tracked per-cpu because
|
|
* this would add another cross-cpu cacheline miss and atomic operation
|
|
* to the wakeup path. Instead we increment on whatever cpu the task ran
|
|
* when it went into uninterruptible state and decrement on whatever cpu
|
|
* did the wakeup. This means that only the sum of nr_uninterruptible over
|
|
* all cpus yields the correct result.
|
|
*
|
|
* This covers the NO_HZ=n code, for extra head-aches, see the comment below.
|
|
*/
|
|
|
|
/* Variables and functions for calc_load */
|
|
static atomic_long_t calc_load_tasks;
|
|
static unsigned long calc_load_update;
|
|
unsigned long avenrun[3];
|
|
EXPORT_SYMBOL(avenrun); /* should be removed */
|
|
|
|
/**
|
|
* get_avenrun - get the load average array
|
|
* @loads: pointer to dest load array
|
|
* @offset: offset to add
|
|
* @shift: shift count to shift the result left
|
|
*
|
|
* These values are estimates at best, so no need for locking.
|
|
*/
|
|
void get_avenrun(unsigned long *loads, unsigned long offset, int shift)
|
|
{
|
|
loads[0] = (avenrun[0] + offset) << shift;
|
|
loads[1] = (avenrun[1] + offset) << shift;
|
|
loads[2] = (avenrun[2] + offset) << shift;
|
|
}
|
|
|
|
static long calc_load_fold_active(struct rq *this_rq)
|
|
{
|
|
long nr_active, delta = 0;
|
|
|
|
nr_active = this_rq->nr_running;
|
|
nr_active += (long) this_rq->nr_uninterruptible;
|
|
|
|
if (nr_active != this_rq->calc_load_active) {
|
|
delta = nr_active - this_rq->calc_load_active;
|
|
this_rq->calc_load_active = nr_active;
|
|
}
|
|
|
|
return delta;
|
|
}
|
|
|
|
/*
|
|
* a1 = a0 * e + a * (1 - e)
|
|
*/
|
|
static unsigned long
|
|
calc_load(unsigned long load, unsigned long exp, unsigned long active)
|
|
{
|
|
load *= exp;
|
|
load += active * (FIXED_1 - exp);
|
|
load += 1UL << (FSHIFT - 1);
|
|
return load >> FSHIFT;
|
|
}
|
|
|
|
#ifdef CONFIG_NO_HZ
|
|
/*
|
|
* Handle NO_HZ for the global load-average.
|
|
*
|
|
* Since the above described distributed algorithm to compute the global
|
|
* load-average relies on per-cpu sampling from the tick, it is affected by
|
|
* NO_HZ.
|
|
*
|
|
* The basic idea is to fold the nr_active delta into a global idle-delta upon
|
|
* entering NO_HZ state such that we can include this as an 'extra' cpu delta
|
|
* when we read the global state.
|
|
*
|
|
* Obviously reality has to ruin such a delightfully simple scheme:
|
|
*
|
|
* - When we go NO_HZ idle during the window, we can negate our sample
|
|
* contribution, causing under-accounting.
|
|
*
|
|
* We avoid this by keeping two idle-delta counters and flipping them
|
|
* when the window starts, thus separating old and new NO_HZ load.
|
|
*
|
|
* The only trick is the slight shift in index flip for read vs write.
|
|
*
|
|
* 0s 5s 10s 15s
|
|
* +10 +10 +10 +10
|
|
* |-|-----------|-|-----------|-|-----------|-|
|
|
* r:0 0 1 1 0 0 1 1 0
|
|
* w:0 1 1 0 0 1 1 0 0
|
|
*
|
|
* This ensures we'll fold the old idle contribution in this window while
|
|
* accumlating the new one.
|
|
*
|
|
* - When we wake up from NO_HZ idle during the window, we push up our
|
|
* contribution, since we effectively move our sample point to a known
|
|
* busy state.
|
|
*
|
|
* This is solved by pushing the window forward, and thus skipping the
|
|
* sample, for this cpu (effectively using the idle-delta for this cpu which
|
|
* was in effect at the time the window opened). This also solves the issue
|
|
* of having to deal with a cpu having been in NOHZ idle for multiple
|
|
* LOAD_FREQ intervals.
|
|
*
|
|
* When making the ILB scale, we should try to pull this in as well.
|
|
*/
|
|
static atomic_long_t calc_load_idle[2];
|
|
static int calc_load_idx;
|
|
|
|
static inline int calc_load_write_idx(void)
|
|
{
|
|
int idx = calc_load_idx;
|
|
|
|
/*
|
|
* See calc_global_nohz(), if we observe the new index, we also
|
|
* need to observe the new update time.
|
|
*/
|
|
smp_rmb();
|
|
|
|
/*
|
|
* If the folding window started, make sure we start writing in the
|
|
* next idle-delta.
|
|
*/
|
|
if (!time_before(jiffies, calc_load_update))
|
|
idx++;
|
|
|
|
return idx & 1;
|
|
}
|
|
|
|
static inline int calc_load_read_idx(void)
|
|
{
|
|
return calc_load_idx & 1;
|
|
}
|
|
|
|
void calc_load_enter_idle(void)
|
|
{
|
|
struct rq *this_rq = this_rq();
|
|
long delta;
|
|
|
|
/*
|
|
* We're going into NOHZ mode, if there's any pending delta, fold it
|
|
* into the pending idle delta.
|
|
*/
|
|
delta = calc_load_fold_active(this_rq);
|
|
if (delta) {
|
|
int idx = calc_load_write_idx();
|
|
atomic_long_add(delta, &calc_load_idle[idx]);
|
|
}
|
|
}
|
|
|
|
void calc_load_exit_idle(void)
|
|
{
|
|
struct rq *this_rq = this_rq();
|
|
|
|
/*
|
|
* If we're still before the sample window, we're done.
|
|
*/
|
|
if (time_before(jiffies, this_rq->calc_load_update))
|
|
return;
|
|
|
|
/*
|
|
* We woke inside or after the sample window, this means we're already
|
|
* accounted through the nohz accounting, so skip the entire deal and
|
|
* sync up for the next window.
|
|
*/
|
|
this_rq->calc_load_update = calc_load_update;
|
|
if (time_before(jiffies, this_rq->calc_load_update + 10))
|
|
this_rq->calc_load_update += LOAD_FREQ;
|
|
}
|
|
|
|
static long calc_load_fold_idle(void)
|
|
{
|
|
int idx = calc_load_read_idx();
|
|
long delta = 0;
|
|
|
|
if (atomic_long_read(&calc_load_idle[idx]))
|
|
delta = atomic_long_xchg(&calc_load_idle[idx], 0);
|
|
|
|
return delta;
|
|
}
|
|
|
|
/**
|
|
* fixed_power_int - compute: x^n, in O(log n) time
|
|
*
|
|
* @x: base of the power
|
|
* @frac_bits: fractional bits of @x
|
|
* @n: power to raise @x to.
|
|
*
|
|
* By exploiting the relation between the definition of the natural power
|
|
* function: x^n := x*x*...*x (x multiplied by itself for n times), and
|
|
* the binary encoding of numbers used by computers: n := \Sum n_i * 2^i,
|
|
* (where: n_i \elem {0, 1}, the binary vector representing n),
|
|
* we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is
|
|
* of course trivially computable in O(log_2 n), the length of our binary
|
|
* vector.
|
|
*/
|
|
static unsigned long
|
|
fixed_power_int(unsigned long x, unsigned int frac_bits, unsigned int n)
|
|
{
|
|
unsigned long result = 1UL << frac_bits;
|
|
|
|
if (n) for (;;) {
|
|
if (n & 1) {
|
|
result *= x;
|
|
result += 1UL << (frac_bits - 1);
|
|
result >>= frac_bits;
|
|
}
|
|
n >>= 1;
|
|
if (!n)
|
|
break;
|
|
x *= x;
|
|
x += 1UL << (frac_bits - 1);
|
|
x >>= frac_bits;
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* a1 = a0 * e + a * (1 - e)
|
|
*
|
|
* a2 = a1 * e + a * (1 - e)
|
|
* = (a0 * e + a * (1 - e)) * e + a * (1 - e)
|
|
* = a0 * e^2 + a * (1 - e) * (1 + e)
|
|
*
|
|
* a3 = a2 * e + a * (1 - e)
|
|
* = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e)
|
|
* = a0 * e^3 + a * (1 - e) * (1 + e + e^2)
|
|
*
|
|
* ...
|
|
*
|
|
* an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1]
|
|
* = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e)
|
|
* = a0 * e^n + a * (1 - e^n)
|
|
*
|
|
* [1] application of the geometric series:
|
|
*
|
|
* n 1 - x^(n+1)
|
|
* S_n := \Sum x^i = -------------
|
|
* i=0 1 - x
|
|
*/
|
|
static unsigned long
|
|
calc_load_n(unsigned long load, unsigned long exp,
|
|
unsigned long active, unsigned int n)
|
|
{
|
|
|
|
return calc_load(load, fixed_power_int(exp, FSHIFT, n), active);
|
|
}
|
|
|
|
/*
|
|
* NO_HZ can leave us missing all per-cpu ticks calling
|
|
* calc_load_account_active(), but since an idle CPU folds its delta into
|
|
* calc_load_tasks_idle per calc_load_account_idle(), all we need to do is fold
|
|
* in the pending idle delta if our idle period crossed a load cycle boundary.
|
|
*
|
|
* Once we've updated the global active value, we need to apply the exponential
|
|
* weights adjusted to the number of cycles missed.
|
|
*/
|
|
static void calc_global_nohz(void)
|
|
{
|
|
long delta, active, n;
|
|
|
|
if (!time_before(jiffies, calc_load_update + 10)) {
|
|
/*
|
|
* Catch-up, fold however many we are behind still
|
|
*/
|
|
delta = jiffies - calc_load_update - 10;
|
|
n = 1 + (delta / LOAD_FREQ);
|
|
|
|
active = atomic_long_read(&calc_load_tasks);
|
|
active = active > 0 ? active * FIXED_1 : 0;
|
|
|
|
avenrun[0] = calc_load_n(avenrun[0], EXP_1, active, n);
|
|
avenrun[1] = calc_load_n(avenrun[1], EXP_5, active, n);
|
|
avenrun[2] = calc_load_n(avenrun[2], EXP_15, active, n);
|
|
|
|
calc_load_update += n * LOAD_FREQ;
|
|
}
|
|
|
|
/*
|
|
* Flip the idle index...
|
|
*
|
|
* Make sure we first write the new time then flip the index, so that
|
|
* calc_load_write_idx() will see the new time when it reads the new
|
|
* index, this avoids a double flip messing things up.
|
|
*/
|
|
smp_wmb();
|
|
calc_load_idx++;
|
|
}
|
|
#else /* !CONFIG_NO_HZ */
|
|
|
|
static inline long calc_load_fold_idle(void) { return 0; }
|
|
static inline void calc_global_nohz(void) { }
|
|
|
|
#endif /* CONFIG_NO_HZ */
|
|
|
|
/*
|
|
* calc_load - update the avenrun load estimates 10 ticks after the
|
|
* CPUs have updated calc_load_tasks.
|
|
*/
|
|
void calc_global_load(unsigned long ticks)
|
|
{
|
|
long active, delta;
|
|
|
|
if (time_before(jiffies, calc_load_update + 10))
|
|
return;
|
|
|
|
/*
|
|
* Fold the 'old' idle-delta to include all NO_HZ cpus.
|
|
*/
|
|
delta = calc_load_fold_idle();
|
|
if (delta)
|
|
atomic_long_add(delta, &calc_load_tasks);
|
|
|
|
active = atomic_long_read(&calc_load_tasks);
|
|
active = active > 0 ? active * FIXED_1 : 0;
|
|
|
|
avenrun[0] = calc_load(avenrun[0], EXP_1, active);
|
|
avenrun[1] = calc_load(avenrun[1], EXP_5, active);
|
|
avenrun[2] = calc_load(avenrun[2], EXP_15, active);
|
|
|
|
calc_load_update += LOAD_FREQ;
|
|
|
|
/*
|
|
* In case we idled for multiple LOAD_FREQ intervals, catch up in bulk.
|
|
*/
|
|
calc_global_nohz();
|
|
}
|
|
|
|
/*
|
|
* Called from update_cpu_load() to periodically update this CPU's
|
|
* active count.
|
|
*/
|
|
static void calc_load_account_active(struct rq *this_rq)
|
|
{
|
|
long delta;
|
|
|
|
if (time_before(jiffies, this_rq->calc_load_update))
|
|
return;
|
|
|
|
delta = calc_load_fold_active(this_rq);
|
|
if (delta)
|
|
atomic_long_add(delta, &calc_load_tasks);
|
|
|
|
this_rq->calc_load_update += LOAD_FREQ;
|
|
}
|
|
|
|
/*
|
|
* End of global load-average stuff
|
|
*/
|
|
|
|
/*
|
|
* The exact cpuload at various idx values, calculated at every tick would be
|
|
* load = (2^idx - 1) / 2^idx * load + 1 / 2^idx * cur_load
|
|
*
|
|
* If a cpu misses updates for n-1 ticks (as it was idle) and update gets called
|
|
* on nth tick when cpu may be busy, then we have:
|
|
* load = ((2^idx - 1) / 2^idx)^(n-1) * load
|
|
* load = (2^idx - 1) / 2^idx) * load + 1 / 2^idx * cur_load
|
|
*
|
|
* decay_load_missed() below does efficient calculation of
|
|
* load = ((2^idx - 1) / 2^idx)^(n-1) * load
|
|
* avoiding 0..n-1 loop doing load = ((2^idx - 1) / 2^idx) * load
|
|
*
|
|
* The calculation is approximated on a 128 point scale.
|
|
* degrade_zero_ticks is the number of ticks after which load at any
|
|
* particular idx is approximated to be zero.
|
|
* degrade_factor is a precomputed table, a row for each load idx.
|
|
* Each column corresponds to degradation factor for a power of two ticks,
|
|
* based on 128 point scale.
|
|
* Example:
|
|
* row 2, col 3 (=12) says that the degradation at load idx 2 after
|
|
* 8 ticks is 12/128 (which is an approximation of exact factor 3^8/4^8).
|
|
*
|
|
* With this power of 2 load factors, we can degrade the load n times
|
|
* by looking at 1 bits in n and doing as many mult/shift instead of
|
|
* n mult/shifts needed by the exact degradation.
|
|
*/
|
|
#define DEGRADE_SHIFT 7
|
|
static const unsigned char
|
|
degrade_zero_ticks[CPU_LOAD_IDX_MAX] = {0, 8, 32, 64, 128};
|
|
static const unsigned char
|
|
degrade_factor[CPU_LOAD_IDX_MAX][DEGRADE_SHIFT + 1] = {
|
|
{0, 0, 0, 0, 0, 0, 0, 0},
|
|
{64, 32, 8, 0, 0, 0, 0, 0},
|
|
{96, 72, 40, 12, 1, 0, 0},
|
|
{112, 98, 75, 43, 15, 1, 0},
|
|
{120, 112, 98, 76, 45, 16, 2} };
|
|
|
|
/*
|
|
* Update cpu_load for any missed ticks, due to tickless idle. The backlog
|
|
* would be when CPU is idle and so we just decay the old load without
|
|
* adding any new load.
|
|
*/
|
|
static unsigned long
|
|
decay_load_missed(unsigned long load, unsigned long missed_updates, int idx)
|
|
{
|
|
int j = 0;
|
|
|
|
if (!missed_updates)
|
|
return load;
|
|
|
|
if (missed_updates >= degrade_zero_ticks[idx])
|
|
return 0;
|
|
|
|
if (idx == 1)
|
|
return load >> missed_updates;
|
|
|
|
while (missed_updates) {
|
|
if (missed_updates % 2)
|
|
load = (load * degrade_factor[idx][j]) >> DEGRADE_SHIFT;
|
|
|
|
missed_updates >>= 1;
|
|
j++;
|
|
}
|
|
return load;
|
|
}
|
|
|
|
/*
|
|
* Update rq->cpu_load[] statistics. This function is usually called every
|
|
* scheduler tick (TICK_NSEC). With tickless idle this will not be called
|
|
* every tick. We fix it up based on jiffies.
|
|
*/
|
|
static void __update_cpu_load(struct rq *this_rq, unsigned long this_load,
|
|
unsigned long pending_updates)
|
|
{
|
|
int i, scale;
|
|
|
|
this_rq->nr_load_updates++;
|
|
|
|
/* Update our load: */
|
|
this_rq->cpu_load[0] = this_load; /* Fasttrack for idx 0 */
|
|
for (i = 1, scale = 2; i < CPU_LOAD_IDX_MAX; i++, scale += scale) {
|
|
unsigned long old_load, new_load;
|
|
|
|
/* scale is effectively 1 << i now, and >> i divides by scale */
|
|
|
|
old_load = this_rq->cpu_load[i];
|
|
old_load = decay_load_missed(old_load, pending_updates - 1, i);
|
|
new_load = this_load;
|
|
/*
|
|
* Round up the averaging division if load is increasing. This
|
|
* prevents us from getting stuck on 9 if the load is 10, for
|
|
* example.
|
|
*/
|
|
if (new_load > old_load)
|
|
new_load += scale - 1;
|
|
|
|
this_rq->cpu_load[i] = (old_load * (scale - 1) + new_load) >> i;
|
|
}
|
|
|
|
sched_avg_update(this_rq);
|
|
}
|
|
|
|
#ifdef CONFIG_NO_HZ
|
|
/*
|
|
* There is no sane way to deal with nohz on smp when using jiffies because the
|
|
* cpu doing the jiffies update might drift wrt the cpu doing the jiffy reading
|
|
* causing off-by-one errors in observed deltas; {0,2} instead of {1,1}.
|
|
*
|
|
* Therefore we cannot use the delta approach from the regular tick since that
|
|
* would seriously skew the load calculation. However we'll make do for those
|
|
* updates happening while idle (nohz_idle_balance) or coming out of idle
|
|
* (tick_nohz_idle_exit).
|
|
*
|
|
* This means we might still be one tick off for nohz periods.
|
|
*/
|
|
|
|
/*
|
|
* Called from nohz_idle_balance() to update the load ratings before doing the
|
|
* idle balance.
|
|
*/
|
|
void update_idle_cpu_load(struct rq *this_rq)
|
|
{
|
|
unsigned long curr_jiffies = ACCESS_ONCE(jiffies);
|
|
unsigned long load = this_rq->load.weight;
|
|
unsigned long pending_updates;
|
|
|
|
/*
|
|
* bail if there's load or we're actually up-to-date.
|
|
*/
|
|
if (load || curr_jiffies == this_rq->last_load_update_tick)
|
|
return;
|
|
|
|
pending_updates = curr_jiffies - this_rq->last_load_update_tick;
|
|
this_rq->last_load_update_tick = curr_jiffies;
|
|
|
|
__update_cpu_load(this_rq, load, pending_updates);
|
|
}
|
|
|
|
/*
|
|
* Called from tick_nohz_idle_exit() -- try and fix up the ticks we missed.
|
|
*/
|
|
void update_cpu_load_nohz(void)
|
|
{
|
|
struct rq *this_rq = this_rq();
|
|
unsigned long curr_jiffies = ACCESS_ONCE(jiffies);
|
|
unsigned long pending_updates;
|
|
|
|
if (curr_jiffies == this_rq->last_load_update_tick)
|
|
return;
|
|
|
|
raw_spin_lock(&this_rq->lock);
|
|
pending_updates = curr_jiffies - this_rq->last_load_update_tick;
|
|
if (pending_updates) {
|
|
this_rq->last_load_update_tick = curr_jiffies;
|
|
/*
|
|
* We were idle, this means load 0, the current load might be
|
|
* !0 due to remote wakeups and the sort.
|
|
*/
|
|
__update_cpu_load(this_rq, 0, pending_updates);
|
|
}
|
|
raw_spin_unlock(&this_rq->lock);
|
|
}
|
|
#endif /* CONFIG_NO_HZ */
|
|
|
|
/*
|
|
* Called from scheduler_tick()
|
|
*/
|
|
static void update_cpu_load_active(struct rq *this_rq)
|
|
{
|
|
/*
|
|
* See the mess around update_idle_cpu_load() / update_cpu_load_nohz().
|
|
*/
|
|
this_rq->last_load_update_tick = jiffies;
|
|
__update_cpu_load(this_rq, this_rq->load.weight, 1);
|
|
|
|
calc_load_account_active(this_rq);
|
|
}
|
|
|
|
#ifdef CONFIG_SMP
|
|
|
|
/*
|
|
* sched_exec - execve() is a valuable balancing opportunity, because at
|
|
* this point the task has the smallest effective memory and cache footprint.
|
|
*/
|
|
void sched_exec(void)
|
|
{
|
|
struct task_struct *p = current;
|
|
unsigned long flags;
|
|
int dest_cpu;
|
|
|
|
raw_spin_lock_irqsave(&p->pi_lock, flags);
|
|
dest_cpu = p->sched_class->select_task_rq(p, SD_BALANCE_EXEC, 0);
|
|
if (dest_cpu == smp_processor_id())
|
|
goto unlock;
|
|
|
|
if (likely(cpu_active(dest_cpu))) {
|
|
struct migration_arg arg = { p, dest_cpu };
|
|
|
|
raw_spin_unlock_irqrestore(&p->pi_lock, flags);
|
|
stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg);
|
|
return;
|
|
}
|
|
unlock:
|
|
raw_spin_unlock_irqrestore(&p->pi_lock, flags);
|
|
}
|
|
|
|
#endif
|
|
|
|
DEFINE_PER_CPU(struct kernel_stat, kstat);
|
|
DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat);
|
|
|
|
EXPORT_PER_CPU_SYMBOL(kstat);
|
|
EXPORT_PER_CPU_SYMBOL(kernel_cpustat);
|
|
|
|
/*
|
|
* Return any ns on the sched_clock that have not yet been accounted in
|
|
* @p in case that task is currently running.
|
|
*
|
|
* Called with task_rq_lock() held on @rq.
|
|
*/
|
|
static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq)
|
|
{
|
|
u64 ns = 0;
|
|
|
|
if (task_current(rq, p)) {
|
|
update_rq_clock(rq);
|
|
ns = rq->clock_task - p->se.exec_start;
|
|
if ((s64)ns < 0)
|
|
ns = 0;
|
|
}
|
|
|
|
return ns;
|
|
}
|
|
|
|
unsigned long long task_delta_exec(struct task_struct *p)
|
|
{
|
|
unsigned long flags;
|
|
struct rq *rq;
|
|
u64 ns = 0;
|
|
|
|
rq = task_rq_lock(p, &flags);
|
|
ns = do_task_delta_exec(p, rq);
|
|
task_rq_unlock(rq, p, &flags);
|
|
|
|
return ns;
|
|
}
|
|
|
|
/*
|
|
* Return accounted runtime for the task.
|
|
* In case the task is currently running, return the runtime plus current's
|
|
* pending runtime that have not been accounted yet.
|
|
*/
|
|
unsigned long long task_sched_runtime(struct task_struct *p)
|
|
{
|
|
unsigned long flags;
|
|
struct rq *rq;
|
|
u64 ns = 0;
|
|
|
|
rq = task_rq_lock(p, &flags);
|
|
ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq);
|
|
task_rq_unlock(rq, p, &flags);
|
|
|
|
return ns;
|
|
}
|
|
|
|
#ifdef CONFIG_CGROUP_CPUACCT
|
|
struct cgroup_subsys cpuacct_subsys;
|
|
struct cpuacct root_cpuacct;
|
|
#endif
|
|
|
|
static inline void task_group_account_field(struct task_struct *p, int index,
|
|
u64 tmp)
|
|
{
|
|
#ifdef CONFIG_CGROUP_CPUACCT
|
|
struct kernel_cpustat *kcpustat;
|
|
struct cpuacct *ca;
|
|
#endif
|
|
/*
|
|
* Since all updates are sure to touch the root cgroup, we
|
|
* get ourselves ahead and touch it first. If the root cgroup
|
|
* is the only cgroup, then nothing else should be necessary.
|
|
*
|
|
*/
|
|
__get_cpu_var(kernel_cpustat).cpustat[index] += tmp;
|
|
|
|
#ifdef CONFIG_CGROUP_CPUACCT
|
|
if (unlikely(!cpuacct_subsys.active))
|
|
return;
|
|
|
|
rcu_read_lock();
|
|
ca = task_ca(p);
|
|
while (ca && (ca != &root_cpuacct)) {
|
|
kcpustat = this_cpu_ptr(ca->cpustat);
|
|
kcpustat->cpustat[index] += tmp;
|
|
ca = parent_ca(ca);
|
|
}
|
|
rcu_read_unlock();
|
|
#endif
|
|
}
|
|
|
|
|
|
/*
|
|
* Account user cpu time to a process.
|
|
* @p: the process that the cpu time gets accounted to
|
|
* @cputime: the cpu time spent in user space since the last update
|
|
* @cputime_scaled: cputime scaled by cpu frequency
|
|
*/
|
|
void account_user_time(struct task_struct *p, cputime_t cputime,
|
|
cputime_t cputime_scaled)
|
|
{
|
|
int index;
|
|
|
|
/* Add user time to process. */
|
|
p->utime += cputime;
|
|
p->utimescaled += cputime_scaled;
|
|
account_group_user_time(p, cputime);
|
|
|
|
index = (TASK_NICE(p) > 0) ? CPUTIME_NICE : CPUTIME_USER;
|
|
|
|
/* Add user time to cpustat. */
|
|
task_group_account_field(p, index, (__force u64) cputime);
|
|
|
|
/* Account for user time used */
|
|
acct_update_integrals(p);
|
|
}
|
|
|
|
/*
|
|
* Account guest cpu time to a process.
|
|
* @p: the process that the cpu time gets accounted to
|
|
* @cputime: the cpu time spent in virtual machine since the last update
|
|
* @cputime_scaled: cputime scaled by cpu frequency
|
|
*/
|
|
static void account_guest_time(struct task_struct *p, cputime_t cputime,
|
|
cputime_t cputime_scaled)
|
|
{
|
|
u64 *cpustat = kcpustat_this_cpu->cpustat;
|
|
|
|
/* Add guest time to process. */
|
|
p->utime += cputime;
|
|
p->utimescaled += cputime_scaled;
|
|
account_group_user_time(p, cputime);
|
|
p->gtime += cputime;
|
|
|
|
/* Add guest time to cpustat. */
|
|
if (TASK_NICE(p) > 0) {
|
|
cpustat[CPUTIME_NICE] += (__force u64) cputime;
|
|
cpustat[CPUTIME_GUEST_NICE] += (__force u64) cputime;
|
|
} else {
|
|
cpustat[CPUTIME_USER] += (__force u64) cputime;
|
|
cpustat[CPUTIME_GUEST] += (__force u64) cputime;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Account system cpu time to a process and desired cpustat field
|
|
* @p: the process that the cpu time gets accounted to
|
|
* @cputime: the cpu time spent in kernel space since the last update
|
|
* @cputime_scaled: cputime scaled by cpu frequency
|
|
* @target_cputime64: pointer to cpustat field that has to be updated
|
|
*/
|
|
static inline
|
|
void __account_system_time(struct task_struct *p, cputime_t cputime,
|
|
cputime_t cputime_scaled, int index)
|
|
{
|
|
/* Add system time to process. */
|
|
p->stime += cputime;
|
|
p->stimescaled += cputime_scaled;
|
|
account_group_system_time(p, cputime);
|
|
|
|
/* Add system time to cpustat. */
|
|
task_group_account_field(p, index, (__force u64) cputime);
|
|
|
|
/* Account for system time used */
|
|
acct_update_integrals(p);
|
|
}
|
|
|
|
/*
|
|
* Account system cpu time to a process.
|
|
* @p: the process that the cpu time gets accounted to
|
|
* @hardirq_offset: the offset to subtract from hardirq_count()
|
|
* @cputime: the cpu time spent in kernel space since the last update
|
|
* @cputime_scaled: cputime scaled by cpu frequency
|
|
*/
|
|
void account_system_time(struct task_struct *p, int hardirq_offset,
|
|
cputime_t cputime, cputime_t cputime_scaled)
|
|
{
|
|
int index;
|
|
|
|
if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
|
|
account_guest_time(p, cputime, cputime_scaled);
|
|
return;
|
|
}
|
|
|
|
if (hardirq_count() - hardirq_offset)
|
|
index = CPUTIME_IRQ;
|
|
else if (in_serving_softirq())
|
|
index = CPUTIME_SOFTIRQ;
|
|
else
|
|
index = CPUTIME_SYSTEM;
|
|
|
|
__account_system_time(p, cputime, cputime_scaled, index);
|
|
}
|
|
|
|
/*
|
|
* Account for involuntary wait time.
|
|
* @cputime: the cpu time spent in involuntary wait
|
|
*/
|
|
void account_steal_time(cputime_t cputime)
|
|
{
|
|
u64 *cpustat = kcpustat_this_cpu->cpustat;
|
|
|
|
cpustat[CPUTIME_STEAL] += (__force u64) cputime;
|
|
}
|
|
|
|
/*
|
|
* Account for idle time.
|
|
* @cputime: the cpu time spent in idle wait
|
|
*/
|
|
void account_idle_time(cputime_t cputime)
|
|
{
|
|
u64 *cpustat = kcpustat_this_cpu->cpustat;
|
|
struct rq *rq = this_rq();
|
|
|
|
if (atomic_read(&rq->nr_iowait) > 0)
|
|
cpustat[CPUTIME_IOWAIT] += (__force u64) cputime;
|
|
else
|
|
cpustat[CPUTIME_IDLE] += (__force u64) cputime;
|
|
}
|
|
|
|
static __always_inline bool steal_account_process_tick(void)
|
|
{
|
|
#ifdef CONFIG_PARAVIRT
|
|
if (static_key_false(¶virt_steal_enabled)) {
|
|
u64 steal, st = 0;
|
|
|
|
steal = paravirt_steal_clock(smp_processor_id());
|
|
steal -= this_rq()->prev_steal_time;
|
|
|
|
st = steal_ticks(steal);
|
|
this_rq()->prev_steal_time += st * TICK_NSEC;
|
|
|
|
account_steal_time(st);
|
|
return st;
|
|
}
|
|
#endif
|
|
return false;
|
|
}
|
|
|
|
#ifndef CONFIG_VIRT_CPU_ACCOUNTING
|
|
|
|
#ifdef CONFIG_IRQ_TIME_ACCOUNTING
|
|
/*
|
|
* Account a tick to a process and cpustat
|
|
* @p: the process that the cpu time gets accounted to
|
|
* @user_tick: is the tick from userspace
|
|
* @rq: the pointer to rq
|
|
*
|
|
* Tick demultiplexing follows the order
|
|
* - pending hardirq update
|
|
* - pending softirq update
|
|
* - user_time
|
|
* - idle_time
|
|
* - system time
|
|
* - check for guest_time
|
|
* - else account as system_time
|
|
*
|
|
* Check for hardirq is done both for system and user time as there is
|
|
* no timer going off while we are on hardirq and hence we may never get an
|
|
* opportunity to update it solely in system time.
|
|
* p->stime and friends are only updated on system time and not on irq
|
|
* softirq as those do not count in task exec_runtime any more.
|
|
*/
|
|
static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
|
|
struct rq *rq)
|
|
{
|
|
cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
|
|
u64 *cpustat = kcpustat_this_cpu->cpustat;
|
|
|
|
if (steal_account_process_tick())
|
|
return;
|
|
|
|
if (irqtime_account_hi_update()) {
|
|
cpustat[CPUTIME_IRQ] += (__force u64) cputime_one_jiffy;
|
|
} else if (irqtime_account_si_update()) {
|
|
cpustat[CPUTIME_SOFTIRQ] += (__force u64) cputime_one_jiffy;
|
|
} else if (this_cpu_ksoftirqd() == p) {
|
|
/*
|
|
* ksoftirqd time do not get accounted in cpu_softirq_time.
|
|
* So, we have to handle it separately here.
|
|
* Also, p->stime needs to be updated for ksoftirqd.
|
|
*/
|
|
__account_system_time(p, cputime_one_jiffy, one_jiffy_scaled,
|
|
CPUTIME_SOFTIRQ);
|
|
} else if (user_tick) {
|
|
account_user_time(p, cputime_one_jiffy, one_jiffy_scaled);
|
|
} else if (p == rq->idle) {
|
|
account_idle_time(cputime_one_jiffy);
|
|
} else if (p->flags & PF_VCPU) { /* System time or guest time */
|
|
account_guest_time(p, cputime_one_jiffy, one_jiffy_scaled);
|
|
} else {
|
|
__account_system_time(p, cputime_one_jiffy, one_jiffy_scaled,
|
|
CPUTIME_SYSTEM);
|
|
}
|
|
}
|
|
|
|
static void irqtime_account_idle_ticks(int ticks)
|
|
{
|
|
int i;
|
|
struct rq *rq = this_rq();
|
|
|
|
for (i = 0; i < ticks; i++)
|
|
irqtime_account_process_tick(current, 0, rq);
|
|
}
|
|
#else /* CONFIG_IRQ_TIME_ACCOUNTING */
|
|
static void irqtime_account_idle_ticks(int ticks) {}
|
|
static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
|
|
struct rq *rq) {}
|
|
#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
|
|
|
|
/*
|
|
* Account a single tick of cpu time.
|
|
* @p: the process that the cpu time gets accounted to
|
|
* @user_tick: indicates if the tick is a user or a system tick
|
|
*/
|
|
void account_process_tick(struct task_struct *p, int user_tick)
|
|
{
|
|
cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
|
|
struct rq *rq = this_rq();
|
|
|
|
if (sched_clock_irqtime) {
|
|
irqtime_account_process_tick(p, user_tick, rq);
|
|
return;
|
|
}
|
|
|
|
if (steal_account_process_tick())
|
|
return;
|
|
|
|
if (user_tick)
|
|
account_user_time(p, cputime_one_jiffy, one_jiffy_scaled);
|
|
else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET))
|
|
account_system_time(p, HARDIRQ_OFFSET, cputime_one_jiffy,
|
|
one_jiffy_scaled);
|
|
else
|
|
account_idle_time(cputime_one_jiffy);
|
|
}
|
|
|
|
/*
|
|
* Account multiple ticks of steal time.
|
|
* @p: the process from which the cpu time has been stolen
|
|
* @ticks: number of stolen ticks
|
|
*/
|
|
void account_steal_ticks(unsigned long ticks)
|
|
{
|
|
account_steal_time(jiffies_to_cputime(ticks));
|
|
}
|
|
|
|
/*
|
|
* Account multiple ticks of idle time.
|
|
* @ticks: number of stolen ticks
|
|
*/
|
|
void account_idle_ticks(unsigned long ticks)
|
|
{
|
|
|
|
if (sched_clock_irqtime) {
|
|
irqtime_account_idle_ticks(ticks);
|
|
return;
|
|
}
|
|
|
|
account_idle_time(jiffies_to_cputime(ticks));
|
|
}
|
|
|
|
#endif
|
|
|
|
/*
|
|
* Use precise platform statistics if available:
|
|
*/
|
|
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
|
|
void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
|
|
{
|
|
*ut = p->utime;
|
|
*st = p->stime;
|
|
}
|
|
|
|
void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
|
|
{
|
|
struct task_cputime cputime;
|
|
|
|
thread_group_cputime(p, &cputime);
|
|
|
|
*ut = cputime.utime;
|
|
*st = cputime.stime;
|
|
}
|
|
#else
|
|
|
|
#ifndef nsecs_to_cputime
|
|
# define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs)
|
|
#endif
|
|
|
|
void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
|
|
{
|
|
cputime_t rtime, utime = p->utime, total = utime + p->stime;
|
|
|
|
/*
|
|
* Use CFS's precise accounting:
|
|
*/
|
|
rtime = nsecs_to_cputime(p->se.sum_exec_runtime);
|
|
|
|
if (total) {
|
|
u64 temp = (__force u64) rtime;
|
|
|
|
temp *= (__force u64) utime;
|
|
do_div(temp, (__force u32) total);
|
|
utime = (__force cputime_t) temp;
|
|
} else
|
|
utime = rtime;
|
|
|
|
/*
|
|
* Compare with previous values, to keep monotonicity:
|
|
*/
|
|
p->prev_utime = max(p->prev_utime, utime);
|
|
p->prev_stime = max(p->prev_stime, rtime - p->prev_utime);
|
|
|
|
*ut = p->prev_utime;
|
|
*st = p->prev_stime;
|
|
}
|
|
|
|
/*
|
|
* Must be called with siglock held.
|
|
*/
|
|
void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
|
|
{
|
|
struct signal_struct *sig = p->signal;
|
|
struct task_cputime cputime;
|
|
cputime_t rtime, utime, total;
|
|
|
|
thread_group_cputime(p, &cputime);
|
|
|
|
total = cputime.utime + cputime.stime;
|
|
rtime = nsecs_to_cputime(cputime.sum_exec_runtime);
|
|
|
|
if (total) {
|
|
u64 temp = (__force u64) rtime;
|
|
|
|
temp *= (__force u64) cputime.utime;
|
|
do_div(temp, (__force u32) total);
|
|
utime = (__force cputime_t) temp;
|
|
} else
|
|
utime = rtime;
|
|
|
|
sig->prev_utime = max(sig->prev_utime, utime);
|
|
sig->prev_stime = max(sig->prev_stime, rtime - sig->prev_utime);
|
|
|
|
*ut = sig->prev_utime;
|
|
*st = sig->prev_stime;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* This function gets called by the timer code, with HZ frequency.
|
|
* We call it with interrupts disabled.
|
|
*/
|
|
void scheduler_tick(void)
|
|
{
|
|
int cpu = smp_processor_id();
|
|
struct rq *rq = cpu_rq(cpu);
|
|
struct task_struct *curr = rq->curr;
|
|
|
|
sched_clock_tick();
|
|
|
|
raw_spin_lock(&rq->lock);
|
|
update_rq_clock(rq);
|
|
update_cpu_load_active(rq);
|
|
curr->sched_class->task_tick(rq, curr, 0);
|
|
raw_spin_unlock(&rq->lock);
|
|
|
|
perf_event_task_tick();
|
|
|
|
#ifdef CONFIG_SMP
|
|
rq->idle_balance = idle_cpu(cpu);
|
|
trigger_load_balance(rq, cpu);
|
|
#endif
|
|
}
|
|
|
|
notrace unsigned long get_parent_ip(unsigned long addr)
|
|
{
|
|
if (in_lock_functions(addr)) {
|
|
addr = CALLER_ADDR2;
|
|
if (in_lock_functions(addr))
|
|
addr = CALLER_ADDR3;
|
|
}
|
|
return addr;
|
|
}
|
|
|
|
#if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
|
|
defined(CONFIG_PREEMPT_TRACER))
|
|
|
|
void __kprobes add_preempt_count(int val)
|
|
{
|
|
#ifdef CONFIG_DEBUG_PREEMPT
|
|
/*
|
|
* Underflow?
|
|
*/
|
|
if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
|
|
return;
|
|
#endif
|
|
preempt_count() += val;
|
|
#ifdef CONFIG_DEBUG_PREEMPT
|
|
/*
|
|
* Spinlock count overflowing soon?
|
|
*/
|
|
DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
|
|
PREEMPT_MASK - 10);
|
|
#endif
|
|
if (preempt_count() == val)
|
|
trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
|
|
}
|
|
EXPORT_SYMBOL(add_preempt_count);
|
|
|
|
void __kprobes sub_preempt_count(int val)
|
|
{
|
|
#ifdef CONFIG_DEBUG_PREEMPT
|
|
/*
|
|
* Underflow?
|
|
*/
|
|
if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
|
|
return;
|
|
/*
|
|
* Is the spinlock portion underflowing?
|
|
*/
|
|
if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
|
|
!(preempt_count() & PREEMPT_MASK)))
|
|
return;
|
|
#endif
|
|
|
|
if (preempt_count() == val)
|
|
trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
|
|
preempt_count() -= val;
|
|
}
|
|
EXPORT_SYMBOL(sub_preempt_count);
|
|
|
|
#endif
|
|
|
|
/*
|
|
* Print scheduling while atomic bug:
|
|
*/
|
|
static noinline void __schedule_bug(struct task_struct *prev)
|
|
{
|
|
if (oops_in_progress)
|
|
return;
|
|
|
|
printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
|
|
prev->comm, prev->pid, preempt_count());
|
|
|
|
debug_show_held_locks(prev);
|
|
print_modules();
|
|
if (irqs_disabled())
|
|
print_irqtrace_events(prev);
|
|
dump_stack();
|
|
add_taint(TAINT_WARN);
|
|
}
|
|
|
|
/*
|
|
* Various schedule()-time debugging checks and statistics:
|
|
*/
|
|
static inline void schedule_debug(struct task_struct *prev)
|
|
{
|
|
/*
|
|
* Test if we are atomic. Since do_exit() needs to call into
|
|
* schedule() atomically, we ignore that path for now.
|
|
* Otherwise, whine if we are scheduling when we should not be.
|
|
*/
|
|
if (unlikely(in_atomic_preempt_off() && !prev->exit_state))
|
|
__schedule_bug(prev);
|
|
rcu_sleep_check();
|
|
|
|
profile_hit(SCHED_PROFILING, __builtin_return_address(0));
|
|
|
|
schedstat_inc(this_rq(), sched_count);
|
|
}
|
|
|
|
static void put_prev_task(struct rq *rq, struct task_struct *prev)
|
|
{
|
|
if (prev->on_rq || rq->skip_clock_update < 0)
|
|
update_rq_clock(rq);
|
|
prev->sched_class->put_prev_task(rq, prev);
|
|
}
|
|
|
|
/*
|
|
* Pick up the highest-prio task:
|
|
*/
|
|
static inline struct task_struct *
|
|
pick_next_task(struct rq *rq)
|
|
{
|
|
const struct sched_class *class;
|
|
struct task_struct *p;
|
|
|
|
/*
|
|
* Optimization: we know that if all tasks are in
|
|
* the fair class we can call that function directly:
|
|
*/
|
|
if (likely(rq->nr_running == rq->cfs.h_nr_running)) {
|
|
p = fair_sched_class.pick_next_task(rq);
|
|
if (likely(p))
|
|
return p;
|
|
}
|
|
|
|
for_each_class(class) {
|
|
p = class->pick_next_task(rq);
|
|
if (p)
|
|
return p;
|
|
}
|
|
|
|
BUG(); /* the idle class will always have a runnable task */
|
|
}
|
|
|
|
/*
|
|
* __schedule() is the main scheduler function.
|
|
*/
|
|
static void __sched __schedule(void)
|
|
{
|
|
struct task_struct *prev, *next;
|
|
unsigned long *switch_count;
|
|
struct rq *rq;
|
|
int cpu;
|
|
|
|
need_resched:
|
|
preempt_disable();
|
|
cpu = smp_processor_id();
|
|
rq = cpu_rq(cpu);
|
|
rcu_note_context_switch(cpu);
|
|
prev = rq->curr;
|
|
|
|
schedule_debug(prev);
|
|
|
|
if (sched_feat(HRTICK))
|
|
hrtick_clear(rq);
|
|
|
|
raw_spin_lock_irq(&rq->lock);
|
|
|
|
switch_count = &prev->nivcsw;
|
|
if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
|
|
if (unlikely(signal_pending_state(prev->state, prev))) {
|
|
prev->state = TASK_RUNNING;
|
|
} else {
|
|
deactivate_task(rq, prev, DEQUEUE_SLEEP);
|
|
prev->on_rq = 0;
|
|
|
|
/*
|
|
* If a worker went to sleep, notify and ask workqueue
|
|
* whether it wants to wake up a task to maintain
|
|
* concurrency.
|
|
*/
|
|
if (prev->flags & PF_WQ_WORKER) {
|
|
struct task_struct *to_wakeup;
|
|
|
|
to_wakeup = wq_worker_sleeping(prev, cpu);
|
|
if (to_wakeup)
|
|
try_to_wake_up_local(to_wakeup);
|
|
}
|
|
}
|
|
switch_count = &prev->nvcsw;
|
|
}
|
|
|
|
pre_schedule(rq, prev);
|
|
|
|
if (unlikely(!rq->nr_running))
|
|
idle_balance(cpu, rq);
|
|
|
|
put_prev_task(rq, prev);
|
|
next = pick_next_task(rq);
|
|
clear_tsk_need_resched(prev);
|
|
rq->skip_clock_update = 0;
|
|
|
|
if (likely(prev != next)) {
|
|
rq->nr_switches++;
|
|
rq->curr = next;
|
|
++*switch_count;
|
|
|
|
context_switch(rq, prev, next); /* unlocks the rq */
|
|
/*
|
|
* The context switch have flipped the stack from under us
|
|
* and restored the local variables which were saved when
|
|
* this task called schedule() in the past. prev == current
|
|
* is still correct, but it can be moved to another cpu/rq.
|
|
*/
|
|
cpu = smp_processor_id();
|
|
rq = cpu_rq(cpu);
|
|
} else
|
|
raw_spin_unlock_irq(&rq->lock);
|
|
|
|
post_schedule(rq);
|
|
|
|
sched_preempt_enable_no_resched();
|
|
if (need_resched())
|
|
goto need_resched;
|
|
}
|
|
|
|
static inline void sched_submit_work(struct task_struct *tsk)
|
|
{
|
|
if (!tsk->state || tsk_is_pi_blocked(tsk))
|
|
return;
|
|
/*
|
|
* If we are going to sleep and we have plugged IO queued,
|
|
* make sure to submit it to avoid deadlocks.
|
|
*/
|
|
if (blk_needs_flush_plug(tsk))
|
|
blk_schedule_flush_plug(tsk);
|
|
}
|
|
|
|
asmlinkage void __sched schedule(void)
|
|
{
|
|
struct task_struct *tsk = current;
|
|
|
|
sched_submit_work(tsk);
|
|
__schedule();
|
|
}
|
|
EXPORT_SYMBOL(schedule);
|
|
|
|
/**
|
|
* schedule_preempt_disabled - called with preemption disabled
|
|
*
|
|
* Returns with preemption disabled. Note: preempt_count must be 1
|
|
*/
|
|
void __sched schedule_preempt_disabled(void)
|
|
{
|
|
sched_preempt_enable_no_resched();
|
|
schedule();
|
|
preempt_disable();
|
|
}
|
|
|
|
#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
|
|
|
|
static inline bool owner_running(struct mutex *lock, struct task_struct *owner)
|
|
{
|
|
if (lock->owner != owner)
|
|
return false;
|
|
|
|
/*
|
|
* Ensure we emit the owner->on_cpu, dereference _after_ checking
|
|
* lock->owner still matches owner, if that fails, owner might
|
|
* point to free()d memory, if it still matches, the rcu_read_lock()
|
|
* ensures the memory stays valid.
|
|
*/
|
|
barrier();
|
|
|
|
return owner->on_cpu;
|
|
}
|
|
|
|
/*
|
|
* Look out! "owner" is an entirely speculative pointer
|
|
* access and not reliable.
|
|
*/
|
|
int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner)
|
|
{
|
|
if (!sched_feat(OWNER_SPIN))
|
|
return 0;
|
|
|
|
rcu_read_lock();
|
|
while (owner_running(lock, owner)) {
|
|
if (need_resched())
|
|
break;
|
|
|
|
arch_mutex_cpu_relax();
|
|
}
|
|
rcu_read_unlock();
|
|
|
|
/*
|
|
* We break out the loop above on need_resched() and when the
|
|
* owner changed, which is a sign for heavy contention. Return
|
|
* success only when lock->owner is NULL.
|
|
*/
|
|
return lock->owner == NULL;
|
|
}
|
|
#endif
|
|
|
|
#ifdef CONFIG_PREEMPT
|
|
/*
|
|
* this is the entry point to schedule() from in-kernel preemption
|
|
* off of preempt_enable. Kernel preemptions off return from interrupt
|
|
* occur there and call schedule directly.
|
|
*/
|
|
asmlinkage void __sched notrace preempt_schedule(void)
|
|
{
|
|
struct thread_info *ti = current_thread_info();
|
|
|
|
/*
|
|
* If there is a non-zero preempt_count or interrupts are disabled,
|
|
* we do not want to preempt the current task. Just return..
|
|
*/
|
|
if (likely(ti->preempt_count || irqs_disabled()))
|
|
return;
|
|
|
|
do {
|
|
add_preempt_count_notrace(PREEMPT_ACTIVE);
|
|
__schedule();
|
|
sub_preempt_count_notrace(PREEMPT_ACTIVE);
|
|
|
|
/*
|
|
* Check again in case we missed a preemption opportunity
|
|
* between schedule and now.
|
|
*/
|
|
barrier();
|
|
} while (need_resched());
|
|
}
|
|
EXPORT_SYMBOL(preempt_schedule);
|
|
|
|
/*
|
|
* this is the entry point to schedule() from kernel preemption
|
|
* off of irq context.
|
|
* Note, that this is called and return with irqs disabled. This will
|
|
* protect us against recursive calling from irq.
|
|
*/
|
|
asmlinkage void __sched preempt_schedule_irq(void)
|
|
{
|
|
struct thread_info *ti = current_thread_info();
|
|
|
|
/* Catch callers which need to be fixed */
|
|
BUG_ON(ti->preempt_count || !irqs_disabled());
|
|
|
|
do {
|
|
add_preempt_count(PREEMPT_ACTIVE);
|
|
local_irq_enable();
|
|
__schedule();
|
|
local_irq_disable();
|
|
sub_preempt_count(PREEMPT_ACTIVE);
|
|
|
|
/*
|
|
* Check again in case we missed a preemption opportunity
|
|
* between schedule and now.
|
|
*/
|
|
barrier();
|
|
} while (need_resched());
|
|
}
|
|
|
|
#endif /* CONFIG_PREEMPT */
|
|
|
|
int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags,
|
|
void *key)
|
|
{
|
|
return try_to_wake_up(curr->private, mode, wake_flags);
|
|
}
|
|
EXPORT_SYMBOL(default_wake_function);
|
|
|
|
/*
|
|
* The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
|
|
* wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
|
|
* number) then we wake all the non-exclusive tasks and one exclusive task.
|
|
*
|
|
* There are circumstances in which we can try to wake a task which has already
|
|
* started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
|
|
* zero in this (rare) case, and we handle it by continuing to scan the queue.
|
|
*/
|
|
static void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
|
|
int nr_exclusive, int wake_flags, void *key)
|
|
{
|
|
wait_queue_t *curr, *next;
|
|
|
|
list_for_each_entry_safe(curr, next, &q->task_list, task_list) {
|
|
unsigned flags = curr->flags;
|
|
|
|
if (curr->func(curr, mode, wake_flags, key) &&
|
|
(flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
|
|
break;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* __wake_up - wake up threads blocked on a waitqueue.
|
|
* @q: the waitqueue
|
|
* @mode: which threads
|
|
* @nr_exclusive: how many wake-one or wake-many threads to wake up
|
|
* @key: is directly passed to the wakeup function
|
|
*
|
|
* It may be assumed that this function implies a write memory barrier before
|
|
* changing the task state if and only if any tasks are woken up.
|
|
*/
|
|
void __wake_up(wait_queue_head_t *q, unsigned int mode,
|
|
int nr_exclusive, void *key)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&q->lock, flags);
|
|
__wake_up_common(q, mode, nr_exclusive, 0, key);
|
|
spin_unlock_irqrestore(&q->lock, flags);
|
|
}
|
|
EXPORT_SYMBOL(__wake_up);
|
|
|
|
/*
|
|
* Same as __wake_up but called with the spinlock in wait_queue_head_t held.
|
|
*/
|
|
void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr)
|
|
{
|
|
__wake_up_common(q, mode, nr, 0, NULL);
|
|
}
|
|
EXPORT_SYMBOL_GPL(__wake_up_locked);
|
|
|
|
void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key)
|
|
{
|
|
__wake_up_common(q, mode, 1, 0, key);
|
|
}
|
|
EXPORT_SYMBOL_GPL(__wake_up_locked_key);
|
|
|
|
/**
|
|
* __wake_up_sync_key - wake up threads blocked on a waitqueue.
|
|
* @q: the waitqueue
|
|
* @mode: which threads
|
|
* @nr_exclusive: how many wake-one or wake-many threads to wake up
|
|
* @key: opaque value to be passed to wakeup targets
|
|
*
|
|
* The sync wakeup differs that the waker knows that it will schedule
|
|
* away soon, so while the target thread will be woken up, it will not
|
|
* be migrated to another CPU - ie. the two threads are 'synchronized'
|
|
* with each other. This can prevent needless bouncing between CPUs.
|
|
*
|
|
* On UP it can prevent extra preemption.
|
|
*
|
|
* It may be assumed that this function implies a write memory barrier before
|
|
* changing the task state if and only if any tasks are woken up.
|
|
*/
|
|
void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode,
|
|
int nr_exclusive, void *key)
|
|
{
|
|
unsigned long flags;
|
|
int wake_flags = WF_SYNC;
|
|
|
|
if (unlikely(!q))
|
|
return;
|
|
|
|
if (unlikely(!nr_exclusive))
|
|
wake_flags = 0;
|
|
|
|
spin_lock_irqsave(&q->lock, flags);
|
|
__wake_up_common(q, mode, nr_exclusive, wake_flags, key);
|
|
spin_unlock_irqrestore(&q->lock, flags);
|
|
}
|
|
EXPORT_SYMBOL_GPL(__wake_up_sync_key);
|
|
|
|
/*
|
|
* __wake_up_sync - see __wake_up_sync_key()
|
|
*/
|
|
void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
|
|
{
|
|
__wake_up_sync_key(q, mode, nr_exclusive, NULL);
|
|
}
|
|
EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */
|
|
|
|
/**
|
|
* complete: - signals a single thread waiting on this completion
|
|
* @x: holds the state of this particular completion
|
|
*
|
|
* This will wake up a single thread waiting on this completion. Threads will be
|
|
* awakened in the same order in which they were queued.
|
|
*
|
|
* See also complete_all(), wait_for_completion() and related routines.
|
|
*
|
|
* It may be assumed that this function implies a write memory barrier before
|
|
* changing the task state if and only if any tasks are woken up.
|
|
*/
|
|
void complete(struct completion *x)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&x->wait.lock, flags);
|
|
x->done++;
|
|
__wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL);
|
|
spin_unlock_irqrestore(&x->wait.lock, flags);
|
|
}
|
|
EXPORT_SYMBOL(complete);
|
|
|
|
/**
|
|
* complete_all: - signals all threads waiting on this completion
|
|
* @x: holds the state of this particular completion
|
|
*
|
|
* This will wake up all threads waiting on this particular completion event.
|
|
*
|
|
* It may be assumed that this function implies a write memory barrier before
|
|
* changing the task state if and only if any tasks are woken up.
|
|
*/
|
|
void complete_all(struct completion *x)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&x->wait.lock, flags);
|
|
x->done += UINT_MAX/2;
|
|
__wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL);
|
|
spin_unlock_irqrestore(&x->wait.lock, flags);
|
|
}
|
|
EXPORT_SYMBOL(complete_all);
|
|
|
|
static inline long __sched
|
|
do_wait_for_common(struct completion *x, long timeout, int state)
|
|
{
|
|
if (!x->done) {
|
|
DECLARE_WAITQUEUE(wait, current);
|
|
|
|
__add_wait_queue_tail_exclusive(&x->wait, &wait);
|
|
do {
|
|
if (signal_pending_state(state, current)) {
|
|
timeout = -ERESTARTSYS;
|
|
break;
|
|
}
|
|
__set_current_state(state);
|
|
spin_unlock_irq(&x->wait.lock);
|
|
timeout = schedule_timeout(timeout);
|
|
spin_lock_irq(&x->wait.lock);
|
|
} while (!x->done && timeout);
|
|
__remove_wait_queue(&x->wait, &wait);
|
|
if (!x->done)
|
|
return timeout;
|
|
}
|
|
x->done--;
|
|
return timeout ?: 1;
|
|
}
|
|
|
|
static long __sched
|
|
wait_for_common(struct completion *x, long timeout, int state)
|
|
{
|
|
might_sleep();
|
|
|
|
spin_lock_irq(&x->wait.lock);
|
|
timeout = do_wait_for_common(x, timeout, state);
|
|
spin_unlock_irq(&x->wait.lock);
|
|
return timeout;
|
|
}
|
|
|
|
/**
|
|
* wait_for_completion: - waits for completion of a task
|
|
* @x: holds the state of this particular completion
|
|
*
|
|
* This waits to be signaled for completion of a specific task. It is NOT
|
|
* interruptible and there is no timeout.
|
|
*
|
|
* See also similar routines (i.e. wait_for_completion_timeout()) with timeout
|
|
* and interrupt capability. Also see complete().
|
|
*/
|
|
void __sched wait_for_completion(struct completion *x)
|
|
{
|
|
wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
|
|
}
|
|
EXPORT_SYMBOL(wait_for_completion);
|
|
|
|
/**
|
|
* wait_for_completion_timeout: - waits for completion of a task (w/timeout)
|
|
* @x: holds the state of this particular completion
|
|
* @timeout: timeout value in jiffies
|
|
*
|
|
* This waits for either a completion of a specific task to be signaled or for a
|
|
* specified timeout to expire. The timeout is in jiffies. It is not
|
|
* interruptible.
|
|
*
|
|
* The return value is 0 if timed out, and positive (at least 1, or number of
|
|
* jiffies left till timeout) if completed.
|
|
*/
|
|
unsigned long __sched
|
|
wait_for_completion_timeout(struct completion *x, unsigned long timeout)
|
|
{
|
|
return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE);
|
|
}
|
|
EXPORT_SYMBOL(wait_for_completion_timeout);
|
|
|
|
/**
|
|
* wait_for_completion_interruptible: - waits for completion of a task (w/intr)
|
|
* @x: holds the state of this particular completion
|
|
*
|
|
* This waits for completion of a specific task to be signaled. It is
|
|
* interruptible.
|
|
*
|
|
* The return value is -ERESTARTSYS if interrupted, 0 if completed.
|
|
*/
|
|
int __sched wait_for_completion_interruptible(struct completion *x)
|
|
{
|
|
long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
|
|
if (t == -ERESTARTSYS)
|
|
return t;
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(wait_for_completion_interruptible);
|
|
|
|
/**
|
|
* wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
|
|
* @x: holds the state of this particular completion
|
|
* @timeout: timeout value in jiffies
|
|
*
|
|
* This waits for either a completion of a specific task to be signaled or for a
|
|
* specified timeout to expire. It is interruptible. The timeout is in jiffies.
|
|
*
|
|
* The return value is -ERESTARTSYS if interrupted, 0 if timed out,
|
|
* positive (at least 1, or number of jiffies left till timeout) if completed.
|
|
*/
|
|
long __sched
|
|
wait_for_completion_interruptible_timeout(struct completion *x,
|
|
unsigned long timeout)
|
|
{
|
|
return wait_for_common(x, timeout, TASK_INTERRUPTIBLE);
|
|
}
|
|
EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
|
|
|
|
/**
|
|
* wait_for_completion_killable: - waits for completion of a task (killable)
|
|
* @x: holds the state of this particular completion
|
|
*
|
|
* This waits to be signaled for completion of a specific task. It can be
|
|
* interrupted by a kill signal.
|
|
*
|
|
* The return value is -ERESTARTSYS if interrupted, 0 if completed.
|
|
*/
|
|
int __sched wait_for_completion_killable(struct completion *x)
|
|
{
|
|
long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE);
|
|
if (t == -ERESTARTSYS)
|
|
return t;
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(wait_for_completion_killable);
|
|
|
|
/**
|
|
* wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable))
|
|
* @x: holds the state of this particular completion
|
|
* @timeout: timeout value in jiffies
|
|
*
|
|
* This waits for either a completion of a specific task to be
|
|
* signaled or for a specified timeout to expire. It can be
|
|
* interrupted by a kill signal. The timeout is in jiffies.
|
|
*
|
|
* The return value is -ERESTARTSYS if interrupted, 0 if timed out,
|
|
* positive (at least 1, or number of jiffies left till timeout) if completed.
|
|
*/
|
|
long __sched
|
|
wait_for_completion_killable_timeout(struct completion *x,
|
|
unsigned long timeout)
|
|
{
|
|
return wait_for_common(x, timeout, TASK_KILLABLE);
|
|
}
|
|
EXPORT_SYMBOL(wait_for_completion_killable_timeout);
|
|
|
|
/**
|
|
* try_wait_for_completion - try to decrement a completion without blocking
|
|
* @x: completion structure
|
|
*
|
|
* Returns: 0 if a decrement cannot be done without blocking
|
|
* 1 if a decrement succeeded.
|
|
*
|
|
* If a completion is being used as a counting completion,
|
|
* attempt to decrement the counter without blocking. This
|
|
* enables us to avoid waiting if the resource the completion
|
|
* is protecting is not available.
|
|
*/
|
|
bool try_wait_for_completion(struct completion *x)
|
|
{
|
|
unsigned long flags;
|
|
int ret = 1;
|
|
|
|
spin_lock_irqsave(&x->wait.lock, flags);
|
|
if (!x->done)
|
|
ret = 0;
|
|
else
|
|
x->done--;
|
|
spin_unlock_irqrestore(&x->wait.lock, flags);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(try_wait_for_completion);
|
|
|
|
/**
|
|
* completion_done - Test to see if a completion has any waiters
|
|
* @x: completion structure
|
|
*
|
|
* Returns: 0 if there are waiters (wait_for_completion() in progress)
|
|
* 1 if there are no waiters.
|
|
*
|
|
*/
|
|
bool completion_done(struct completion *x)
|
|
{
|
|
unsigned long flags;
|
|
int ret = 1;
|
|
|
|
spin_lock_irqsave(&x->wait.lock, flags);
|
|
if (!x->done)
|
|
ret = 0;
|
|
spin_unlock_irqrestore(&x->wait.lock, flags);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(completion_done);
|
|
|
|
static long __sched
|
|
sleep_on_common(wait_queue_head_t *q, int state, long timeout)
|
|
{
|
|
unsigned long flags;
|
|
wait_queue_t wait;
|
|
|
|
init_waitqueue_entry(&wait, current);
|
|
|
|
__set_current_state(state);
|
|
|
|
spin_lock_irqsave(&q->lock, flags);
|
|
__add_wait_queue(q, &wait);
|
|
spin_unlock(&q->lock);
|
|
timeout = schedule_timeout(timeout);
|
|
spin_lock_irq(&q->lock);
|
|
__remove_wait_queue(q, &wait);
|
|
spin_unlock_irqrestore(&q->lock, flags);
|
|
|
|
return timeout;
|
|
}
|
|
|
|
void __sched interruptible_sleep_on(wait_queue_head_t *q)
|
|
{
|
|
sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
|
|
}
|
|
EXPORT_SYMBOL(interruptible_sleep_on);
|
|
|
|
long __sched
|
|
interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
|
|
{
|
|
return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout);
|
|
}
|
|
EXPORT_SYMBOL(interruptible_sleep_on_timeout);
|
|
|
|
void __sched sleep_on(wait_queue_head_t *q)
|
|
{
|
|
sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
|
|
}
|
|
EXPORT_SYMBOL(sleep_on);
|
|
|
|
long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
|
|
{
|
|
return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout);
|
|
}
|
|
EXPORT_SYMBOL(sleep_on_timeout);
|
|
|
|
#ifdef CONFIG_RT_MUTEXES
|
|
|
|
/*
|
|
* rt_mutex_setprio - set the current priority of a task
|
|
* @p: task
|
|
* @prio: prio value (kernel-internal form)
|
|
*
|
|
* This function changes the 'effective' priority of a task. It does
|
|
* not touch ->normal_prio like __setscheduler().
|
|
*
|
|
* Used by the rt_mutex code to implement priority inheritance logic.
|
|
*/
|
|
void rt_mutex_setprio(struct task_struct *p, int prio)
|
|
{
|
|
int oldprio, on_rq, running;
|
|
struct rq *rq;
|
|
const struct sched_class *prev_class;
|
|
|
|
BUG_ON(prio < 0 || prio > MAX_PRIO);
|
|
|
|
rq = __task_rq_lock(p);
|
|
|
|
/*
|
|
* Idle task boosting is a nono in general. There is one
|
|
* exception, when PREEMPT_RT and NOHZ is active:
|
|
*
|
|
* The idle task calls get_next_timer_interrupt() and holds
|
|
* the timer wheel base->lock on the CPU and another CPU wants
|
|
* to access the timer (probably to cancel it). We can safely
|
|
* ignore the boosting request, as the idle CPU runs this code
|
|
* with interrupts disabled and will complete the lock
|
|
* protected section without being interrupted. So there is no
|
|
* real need to boost.
|
|
*/
|
|
if (unlikely(p == rq->idle)) {
|
|
WARN_ON(p != rq->curr);
|
|
WARN_ON(p->pi_blocked_on);
|
|
goto out_unlock;
|
|
}
|
|
|
|
trace_sched_pi_setprio(p, prio);
|
|
oldprio = p->prio;
|
|
prev_class = p->sched_class;
|
|
on_rq = p->on_rq;
|
|
running = task_current(rq, p);
|
|
if (on_rq)
|
|
dequeue_task(rq, p, 0);
|
|
if (running)
|
|
p->sched_class->put_prev_task(rq, p);
|
|
|
|
if (rt_prio(prio))
|
|
p->sched_class = &rt_sched_class;
|
|
else
|
|
p->sched_class = &fair_sched_class;
|
|
|
|
p->prio = prio;
|
|
|
|
if (running)
|
|
p->sched_class->set_curr_task(rq);
|
|
if (on_rq)
|
|
enqueue_task(rq, p, oldprio < prio ? ENQUEUE_HEAD : 0);
|
|
|
|
check_class_changed(rq, p, prev_class, oldprio);
|
|
out_unlock:
|
|
__task_rq_unlock(rq);
|
|
}
|
|
#endif
|
|
void set_user_nice(struct task_struct *p, long nice)
|
|
{
|
|
int old_prio, delta, on_rq;
|
|
unsigned long flags;
|
|
struct rq *rq;
|
|
|
|
if (TASK_NICE(p) == nice || nice < -20 || nice > 19)
|
|
return;
|
|
/*
|
|
* We have to be careful, if called from sys_setpriority(),
|
|
* the task might be in the middle of scheduling on another CPU.
|
|
*/
|
|
rq = task_rq_lock(p, &flags);
|
|
/*
|
|
* The RT priorities are set via sched_setscheduler(), but we still
|
|
* allow the 'normal' nice value to be set - but as expected
|
|
* it wont have any effect on scheduling until the task is
|
|
* SCHED_FIFO/SCHED_RR:
|
|
*/
|
|
if (task_has_rt_policy(p)) {
|
|
p->static_prio = NICE_TO_PRIO(nice);
|
|
goto out_unlock;
|
|
}
|
|
on_rq = p->on_rq;
|
|
if (on_rq)
|
|
dequeue_task(rq, p, 0);
|
|
|
|
p->static_prio = NICE_TO_PRIO(nice);
|
|
set_load_weight(p);
|
|
old_prio = p->prio;
|
|
p->prio = effective_prio(p);
|
|
delta = p->prio - old_prio;
|
|
|
|
if (on_rq) {
|
|
enqueue_task(rq, p, 0);
|
|
/*
|
|
* If the task increased its priority or is running and
|
|
* lowered its priority, then reschedule its CPU:
|
|
*/
|
|
if (delta < 0 || (delta > 0 && task_running(rq, p)))
|
|
resched_task(rq->curr);
|
|
}
|
|
out_unlock:
|
|
task_rq_unlock(rq, p, &flags);
|
|
}
|
|
EXPORT_SYMBOL(set_user_nice);
|
|
|
|
/*
|
|
* can_nice - check if a task can reduce its nice value
|
|
* @p: task
|
|
* @nice: nice value
|
|
*/
|
|
int can_nice(const struct task_struct *p, const int nice)
|
|
{
|
|
/* convert nice value [19,-20] to rlimit style value [1,40] */
|
|
int nice_rlim = 20 - nice;
|
|
|
|
return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) ||
|
|
capable(CAP_SYS_NICE));
|
|
}
|
|
|
|
#ifdef __ARCH_WANT_SYS_NICE
|
|
|
|
/*
|
|
* sys_nice - change the priority of the current process.
|
|
* @increment: priority increment
|
|
*
|
|
* sys_setpriority is a more generic, but much slower function that
|
|
* does similar things.
|
|
*/
|
|
SYSCALL_DEFINE1(nice, int, increment)
|
|
{
|
|
long nice, retval;
|
|
|
|
/*
|
|
* Setpriority might change our priority at the same moment.
|
|
* We don't have to worry. Conceptually one call occurs first
|
|
* and we have a single winner.
|
|
*/
|
|
if (increment < -40)
|
|
increment = -40;
|
|
if (increment > 40)
|
|
increment = 40;
|
|
|
|
nice = TASK_NICE(current) + increment;
|
|
if (nice < -20)
|
|
nice = -20;
|
|
if (nice > 19)
|
|
nice = 19;
|
|
|
|
if (increment < 0 && !can_nice(current, nice))
|
|
return -EPERM;
|
|
|
|
retval = security_task_setnice(current, nice);
|
|
if (retval)
|
|
return retval;
|
|
|
|
set_user_nice(current, nice);
|
|
return 0;
|
|
}
|
|
|
|
#endif
|
|
|
|
/**
|
|
* task_prio - return the priority value of a given task.
|
|
* @p: the task in question.
|
|
*
|
|
* This is the priority value as seen by users in /proc.
|
|
* RT tasks are offset by -200. Normal tasks are centered
|
|
* around 0, value goes from -16 to +15.
|
|
*/
|
|
int task_prio(const struct task_struct *p)
|
|
{
|
|
return p->prio - MAX_RT_PRIO;
|
|
}
|
|
|
|
/**
|
|
* task_nice - return the nice value of a given task.
|
|
* @p: the task in question.
|
|
*/
|
|
int task_nice(const struct task_struct *p)
|
|
{
|
|
return TASK_NICE(p);
|
|
}
|
|
EXPORT_SYMBOL(task_nice);
|
|
|
|
/**
|
|
* idle_cpu - is a given cpu idle currently?
|
|
* @cpu: the processor in question.
|
|
*/
|
|
int idle_cpu(int cpu)
|
|
{
|
|
struct rq *rq = cpu_rq(cpu);
|
|
|
|
if (rq->curr != rq->idle)
|
|
return 0;
|
|
|
|
if (rq->nr_running)
|
|
return 0;
|
|
|
|
#ifdef CONFIG_SMP
|
|
if (!llist_empty(&rq->wake_list))
|
|
return 0;
|
|
#endif
|
|
|
|
return 1;
|
|
}
|
|
|
|
/**
|
|
* idle_task - return the idle task for a given cpu.
|
|
* @cpu: the processor in question.
|
|
*/
|
|
struct task_struct *idle_task(int cpu)
|
|
{
|
|
return cpu_rq(cpu)->idle;
|
|
}
|
|
|
|
/**
|
|
* find_process_by_pid - find a process with a matching PID value.
|
|
* @pid: the pid in question.
|
|
*/
|
|
static struct task_struct *find_process_by_pid(pid_t pid)
|
|
{
|
|
return pid ? find_task_by_vpid(pid) : current;
|
|
}
|
|
|
|
/* Actually do priority change: must hold rq lock. */
|
|
static void
|
|
__setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
|
|
{
|
|
p->policy = policy;
|
|
p->rt_priority = prio;
|
|
p->normal_prio = normal_prio(p);
|
|
/* we are holding p->pi_lock already */
|
|
p->prio = rt_mutex_getprio(p);
|
|
if (rt_prio(p->prio))
|
|
p->sched_class = &rt_sched_class;
|
|
else
|
|
p->sched_class = &fair_sched_class;
|
|
set_load_weight(p);
|
|
}
|
|
|
|
/*
|
|
* check the target process has a UID that matches the current process's
|
|
*/
|
|
static bool check_same_owner(struct task_struct *p)
|
|
{
|
|
const struct cred *cred = current_cred(), *pcred;
|
|
bool match;
|
|
|
|
rcu_read_lock();
|
|
pcred = __task_cred(p);
|
|
match = (uid_eq(cred->euid, pcred->euid) ||
|
|
uid_eq(cred->euid, pcred->uid));
|
|
rcu_read_unlock();
|
|
return match;
|
|
}
|
|
|
|
static int __sched_setscheduler(struct task_struct *p, int policy,
|
|
const struct sched_param *param, bool user)
|
|
{
|
|
int retval, oldprio, oldpolicy = -1, on_rq, running;
|
|
unsigned long flags;
|
|
const struct sched_class *prev_class;
|
|
struct rq *rq;
|
|
int reset_on_fork;
|
|
|
|
/* may grab non-irq protected spin_locks */
|
|
BUG_ON(in_interrupt());
|
|
recheck:
|
|
/* double check policy once rq lock held */
|
|
if (policy < 0) {
|
|
reset_on_fork = p->sched_reset_on_fork;
|
|
policy = oldpolicy = p->policy;
|
|
} else {
|
|
reset_on_fork = !!(policy & SCHED_RESET_ON_FORK);
|
|
policy &= ~SCHED_RESET_ON_FORK;
|
|
|
|
if (policy != SCHED_FIFO && policy != SCHED_RR &&
|
|
policy != SCHED_NORMAL && policy != SCHED_BATCH &&
|
|
policy != SCHED_IDLE)
|
|
return -EINVAL;
|
|
}
|
|
|
|
/*
|
|
* Valid priorities for SCHED_FIFO and SCHED_RR are
|
|
* 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
|
|
* SCHED_BATCH and SCHED_IDLE is 0.
|
|
*/
|
|
if (param->sched_priority < 0 ||
|
|
(p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) ||
|
|
(!p->mm && param->sched_priority > MAX_RT_PRIO-1))
|
|
return -EINVAL;
|
|
if (rt_policy(policy) != (param->sched_priority != 0))
|
|
return -EINVAL;
|
|
|
|
/*
|
|
* Allow unprivileged RT tasks to decrease priority:
|
|
*/
|
|
if (user && !capable(CAP_SYS_NICE)) {
|
|
if (rt_policy(policy)) {
|
|
unsigned long rlim_rtprio =
|
|
task_rlimit(p, RLIMIT_RTPRIO);
|
|
|
|
/* can't set/change the rt policy */
|
|
if (policy != p->policy && !rlim_rtprio)
|
|
return -EPERM;
|
|
|
|
/* can't increase priority */
|
|
if (param->sched_priority > p->rt_priority &&
|
|
param->sched_priority > rlim_rtprio)
|
|
return -EPERM;
|
|
}
|
|
|
|
/*
|
|
* Treat SCHED_IDLE as nice 20. Only allow a switch to
|
|
* SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
|
|
*/
|
|
if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) {
|
|
if (!can_nice(p, TASK_NICE(p)))
|
|
return -EPERM;
|
|
}
|
|
|
|
/* can't change other user's priorities */
|
|
if (!check_same_owner(p))
|
|
return -EPERM;
|
|
|
|
/* Normal users shall not reset the sched_reset_on_fork flag */
|
|
if (p->sched_reset_on_fork && !reset_on_fork)
|
|
return -EPERM;
|
|
}
|
|
|
|
if (user) {
|
|
retval = security_task_setscheduler(p);
|
|
if (retval)
|
|
return retval;
|
|
}
|
|
|
|
/*
|
|
* make sure no PI-waiters arrive (or leave) while we are
|
|
* changing the priority of the task:
|
|
*
|
|
* To be able to change p->policy safely, the appropriate
|
|
* runqueue lock must be held.
|
|
*/
|
|
rq = task_rq_lock(p, &flags);
|
|
|
|
/*
|
|
* Changing the policy of the stop threads its a very bad idea
|
|
*/
|
|
if (p == rq->stop) {
|
|
task_rq_unlock(rq, p, &flags);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/*
|
|
* If not changing anything there's no need to proceed further:
|
|
*/
|
|
if (unlikely(policy == p->policy && (!rt_policy(policy) ||
|
|
param->sched_priority == p->rt_priority))) {
|
|
|
|
__task_rq_unlock(rq);
|
|
raw_spin_unlock_irqrestore(&p->pi_lock, flags);
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_RT_GROUP_SCHED
|
|
if (user) {
|
|
/*
|
|
* Do not allow realtime tasks into groups that have no runtime
|
|
* assigned.
|
|
*/
|
|
if (rt_bandwidth_enabled() && rt_policy(policy) &&
|
|
task_group(p)->rt_bandwidth.rt_runtime == 0 &&
|
|
!task_group_is_autogroup(task_group(p))) {
|
|
task_rq_unlock(rq, p, &flags);
|
|
return -EPERM;
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/* recheck policy now with rq lock held */
|
|
if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
|
|
policy = oldpolicy = -1;
|
|
task_rq_unlock(rq, p, &flags);
|
|
goto recheck;
|
|
}
|
|
on_rq = p->on_rq;
|
|
running = task_current(rq, p);
|
|
if (on_rq)
|
|
dequeue_task(rq, p, 0);
|
|
if (running)
|
|
p->sched_class->put_prev_task(rq, p);
|
|
|
|
p->sched_reset_on_fork = reset_on_fork;
|
|
|
|
oldprio = p->prio;
|
|
prev_class = p->sched_class;
|
|
__setscheduler(rq, p, policy, param->sched_priority);
|
|
|
|
if (running)
|
|
p->sched_class->set_curr_task(rq);
|
|
if (on_rq)
|
|
enqueue_task(rq, p, 0);
|
|
|
|
check_class_changed(rq, p, prev_class, oldprio);
|
|
task_rq_unlock(rq, p, &flags);
|
|
|
|
rt_mutex_adjust_pi(p);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
|
|
* @p: the task in question.
|
|
* @policy: new policy.
|
|
* @param: structure containing the new RT priority.
|
|
*
|
|
* NOTE that the task may be already dead.
|
|
*/
|
|
int sched_setscheduler(struct task_struct *p, int policy,
|
|
const struct sched_param *param)
|
|
{
|
|
return __sched_setscheduler(p, policy, param, true);
|
|
}
|
|
EXPORT_SYMBOL_GPL(sched_setscheduler);
|
|
|
|
/**
|
|
* sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
|
|
* @p: the task in question.
|
|
* @policy: new policy.
|
|
* @param: structure containing the new RT priority.
|
|
*
|
|
* Just like sched_setscheduler, only don't bother checking if the
|
|
* current context has permission. For example, this is needed in
|
|
* stop_machine(): we create temporary high priority worker threads,
|
|
* but our caller might not have that capability.
|
|
*/
|
|
int sched_setscheduler_nocheck(struct task_struct *p, int policy,
|
|
const struct sched_param *param)
|
|
{
|
|
return __sched_setscheduler(p, policy, param, false);
|
|
}
|
|
|
|
static int
|
|
do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
|
|
{
|
|
struct sched_param lparam;
|
|
struct task_struct *p;
|
|
int retval;
|
|
|
|
if (!param || pid < 0)
|
|
return -EINVAL;
|
|
if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
|
|
return -EFAULT;
|
|
|
|
rcu_read_lock();
|
|
retval = -ESRCH;
|
|
p = find_process_by_pid(pid);
|
|
if (p != NULL)
|
|
retval = sched_setscheduler(p, policy, &lparam);
|
|
rcu_read_unlock();
|
|
|
|
return retval;
|
|
}
|
|
|
|
/**
|
|
* sys_sched_setscheduler - set/change the scheduler policy and RT priority
|
|
* @pid: the pid in question.
|
|
* @policy: new policy.
|
|
* @param: structure containing the new RT priority.
|
|
*/
|
|
SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy,
|
|
struct sched_param __user *, param)
|
|
{
|
|
/* negative values for policy are not valid */
|
|
if (policy < 0)
|
|
return -EINVAL;
|
|
|
|
return do_sched_setscheduler(pid, policy, param);
|
|
}
|
|
|
|
/**
|
|
* sys_sched_setparam - set/change the RT priority of a thread
|
|
* @pid: the pid in question.
|
|
* @param: structure containing the new RT priority.
|
|
*/
|
|
SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
|
|
{
|
|
return do_sched_setscheduler(pid, -1, param);
|
|
}
|
|
|
|
/**
|
|
* sys_sched_getscheduler - get the policy (scheduling class) of a thread
|
|
* @pid: the pid in question.
|
|
*/
|
|
SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
|
|
{
|
|
struct task_struct *p;
|
|
int retval;
|
|
|
|
if (pid < 0)
|
|
return -EINVAL;
|
|
|
|
retval = -ESRCH;
|
|
rcu_read_lock();
|
|
p = find_process_by_pid(pid);
|
|
if (p) {
|
|
retval = security_task_getscheduler(p);
|
|
if (!retval)
|
|
retval = p->policy
|
|
| (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0);
|
|
}
|
|
rcu_read_unlock();
|
|
return retval;
|
|
}
|
|
|
|
/**
|
|
* sys_sched_getparam - get the RT priority of a thread
|
|
* @pid: the pid in question.
|
|
* @param: structure containing the RT priority.
|
|
*/
|
|
SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
|
|
{
|
|
struct sched_param lp;
|
|
struct task_struct *p;
|
|
int retval;
|
|
|
|
if (!param || pid < 0)
|
|
return -EINVAL;
|
|
|
|
rcu_read_lock();
|
|
p = find_process_by_pid(pid);
|
|
retval = -ESRCH;
|
|
if (!p)
|
|
goto out_unlock;
|
|
|
|
retval = security_task_getscheduler(p);
|
|
if (retval)
|
|
goto out_unlock;
|
|
|
|
lp.sched_priority = p->rt_priority;
|
|
rcu_read_unlock();
|
|
|
|
/*
|
|
* This one might sleep, we cannot do it with a spinlock held ...
|
|
*/
|
|
retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
|
|
|
|
return retval;
|
|
|
|
out_unlock:
|
|
rcu_read_unlock();
|
|
return retval;
|
|
}
|
|
|
|
long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
|
|
{
|
|
cpumask_var_t cpus_allowed, new_mask;
|
|
struct task_struct *p;
|
|
int retval;
|
|
|
|
get_online_cpus();
|
|
rcu_read_lock();
|
|
|
|
p = find_process_by_pid(pid);
|
|
if (!p) {
|
|
rcu_read_unlock();
|
|
put_online_cpus();
|
|
return -ESRCH;
|
|
}
|
|
|
|
/* Prevent p going away */
|
|
get_task_struct(p);
|
|
rcu_read_unlock();
|
|
|
|
if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
|
|
retval = -ENOMEM;
|
|
goto out_put_task;
|
|
}
|
|
if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
|
|
retval = -ENOMEM;
|
|
goto out_free_cpus_allowed;
|
|
}
|
|
retval = -EPERM;
|
|
if (!check_same_owner(p) && !ns_capable(task_user_ns(p), CAP_SYS_NICE))
|
|
goto out_unlock;
|
|
|
|
retval = security_task_setscheduler(p);
|
|
if (retval)
|
|
goto out_unlock;
|
|
|
|
cpuset_cpus_allowed(p, cpus_allowed);
|
|
cpumask_and(new_mask, in_mask, cpus_allowed);
|
|
again:
|
|
retval = set_cpus_allowed_ptr(p, new_mask);
|
|
|
|
if (!retval) {
|
|
cpuset_cpus_allowed(p, cpus_allowed);
|
|
if (!cpumask_subset(new_mask, cpus_allowed)) {
|
|
/*
|
|
* We must have raced with a concurrent cpuset
|
|
* update. Just reset the cpus_allowed to the
|
|
* cpuset's cpus_allowed
|
|
*/
|
|
cpumask_copy(new_mask, cpus_allowed);
|
|
goto again;
|
|
}
|
|
}
|
|
out_unlock:
|
|
free_cpumask_var(new_mask);
|
|
out_free_cpus_allowed:
|
|
free_cpumask_var(cpus_allowed);
|
|
out_put_task:
|
|
put_task_struct(p);
|
|
put_online_cpus();
|
|
return retval;
|
|
}
|
|
|
|
static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
|
|
struct cpumask *new_mask)
|
|
{
|
|
if (len < cpumask_size())
|
|
cpumask_clear(new_mask);
|
|
else if (len > cpumask_size())
|
|
len = cpumask_size();
|
|
|
|
return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
|
|
}
|
|
|
|
/**
|
|
* sys_sched_setaffinity - set the cpu affinity of a process
|
|
* @pid: pid of the process
|
|
* @len: length in bytes of the bitmask pointed to by user_mask_ptr
|
|
* @user_mask_ptr: user-space pointer to the new cpu mask
|
|
*/
|
|
SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
|
|
unsigned long __user *, user_mask_ptr)
|
|
{
|
|
cpumask_var_t new_mask;
|
|
int retval;
|
|
|
|
if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
|
|
return -ENOMEM;
|
|
|
|
retval = get_user_cpu_mask(user_mask_ptr, len, new_mask);
|
|
if (retval == 0)
|
|
retval = sched_setaffinity(pid, new_mask);
|
|
free_cpumask_var(new_mask);
|
|
return retval;
|
|
}
|
|
|
|
long sched_getaffinity(pid_t pid, struct cpumask *mask)
|
|
{
|
|
struct task_struct *p;
|
|
unsigned long flags;
|
|
int retval;
|
|
|
|
get_online_cpus();
|
|
rcu_read_lock();
|
|
|
|
retval = -ESRCH;
|
|
p = find_process_by_pid(pid);
|
|
if (!p)
|
|
goto out_unlock;
|
|
|
|
retval = security_task_getscheduler(p);
|
|
if (retval)
|
|
goto out_unlock;
|
|
|
|
raw_spin_lock_irqsave(&p->pi_lock, flags);
|
|
cpumask_and(mask, &p->cpus_allowed, cpu_online_mask);
|
|
raw_spin_unlock_irqrestore(&p->pi_lock, flags);
|
|
|
|
out_unlock:
|
|
rcu_read_unlock();
|
|
put_online_cpus();
|
|
|
|
return retval;
|
|
}
|
|
|
|
/**
|
|
* sys_sched_getaffinity - get the cpu affinity of a process
|
|
* @pid: pid of the process
|
|
* @len: length in bytes of the bitmask pointed to by user_mask_ptr
|
|
* @user_mask_ptr: user-space pointer to hold the current cpu mask
|
|
*/
|
|
SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
|
|
unsigned long __user *, user_mask_ptr)
|
|
{
|
|
int ret;
|
|
cpumask_var_t mask;
|
|
|
|
if ((len * BITS_PER_BYTE) < nr_cpu_ids)
|
|
return -EINVAL;
|
|
if (len & (sizeof(unsigned long)-1))
|
|
return -EINVAL;
|
|
|
|
if (!alloc_cpumask_var(&mask, GFP_KERNEL))
|
|
return -ENOMEM;
|
|
|
|
ret = sched_getaffinity(pid, mask);
|
|
if (ret == 0) {
|
|
size_t retlen = min_t(size_t, len, cpumask_size());
|
|
|
|
if (copy_to_user(user_mask_ptr, mask, retlen))
|
|
ret = -EFAULT;
|
|
else
|
|
ret = retlen;
|
|
}
|
|
free_cpumask_var(mask);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* sys_sched_yield - yield the current processor to other threads.
|
|
*
|
|
* This function yields the current CPU to other tasks. If there are no
|
|
* other threads running on this CPU then this function will return.
|
|
*/
|
|
SYSCALL_DEFINE0(sched_yield)
|
|
{
|
|
struct rq *rq = this_rq_lock();
|
|
|
|
schedstat_inc(rq, yld_count);
|
|
current->sched_class->yield_task(rq);
|
|
|
|
/*
|
|
* Since we are going to call schedule() anyway, there's
|
|
* no need to preempt or enable interrupts:
|
|
*/
|
|
__release(rq->lock);
|
|
spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
|
|
do_raw_spin_unlock(&rq->lock);
|
|
sched_preempt_enable_no_resched();
|
|
|
|
schedule();
|
|
|
|
return 0;
|
|
}
|
|
|
|
static inline int should_resched(void)
|
|
{
|
|
return need_resched() && !(preempt_count() & PREEMPT_ACTIVE);
|
|
}
|
|
|
|
static void __cond_resched(void)
|
|
{
|
|
add_preempt_count(PREEMPT_ACTIVE);
|
|
__schedule();
|
|
sub_preempt_count(PREEMPT_ACTIVE);
|
|
}
|
|
|
|
int __sched _cond_resched(void)
|
|
{
|
|
if (should_resched()) {
|
|
__cond_resched();
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(_cond_resched);
|
|
|
|
/*
|
|
* __cond_resched_lock() - if a reschedule is pending, drop the given lock,
|
|
* call schedule, and on return reacquire the lock.
|
|
*
|
|
* This works OK both with and without CONFIG_PREEMPT. We do strange low-level
|
|
* operations here to prevent schedule() from being called twice (once via
|
|
* spin_unlock(), once by hand).
|
|
*/
|
|
int __cond_resched_lock(spinlock_t *lock)
|
|
{
|
|
int resched = should_resched();
|
|
int ret = 0;
|
|
|
|
lockdep_assert_held(lock);
|
|
|
|
if (spin_needbreak(lock) || resched) {
|
|
spin_unlock(lock);
|
|
if (resched)
|
|
__cond_resched();
|
|
else
|
|
cpu_relax();
|
|
ret = 1;
|
|
spin_lock(lock);
|
|
}
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(__cond_resched_lock);
|
|
|
|
int __sched __cond_resched_softirq(void)
|
|
{
|
|
BUG_ON(!in_softirq());
|
|
|
|
if (should_resched()) {
|
|
local_bh_enable();
|
|
__cond_resched();
|
|
local_bh_disable();
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(__cond_resched_softirq);
|
|
|
|
/**
|
|
* yield - yield the current processor to other threads.
|
|
*
|
|
* Do not ever use this function, there's a 99% chance you're doing it wrong.
|
|
*
|
|
* The scheduler is at all times free to pick the calling task as the most
|
|
* eligible task to run, if removing the yield() call from your code breaks
|
|
* it, its already broken.
|
|
*
|
|
* Typical broken usage is:
|
|
*
|
|
* while (!event)
|
|
* yield();
|
|
*
|
|
* where one assumes that yield() will let 'the other' process run that will
|
|
* make event true. If the current task is a SCHED_FIFO task that will never
|
|
* happen. Never use yield() as a progress guarantee!!
|
|
*
|
|
* If you want to use yield() to wait for something, use wait_event().
|
|
* If you want to use yield() to be 'nice' for others, use cond_resched().
|
|
* If you still want to use yield(), do not!
|
|
*/
|
|
void __sched yield(void)
|
|
{
|
|
set_current_state(TASK_RUNNING);
|
|
sys_sched_yield();
|
|
}
|
|
EXPORT_SYMBOL(yield);
|
|
|
|
/**
|
|
* yield_to - yield the current processor to another thread in
|
|
* your thread group, or accelerate that thread toward the
|
|
* processor it's on.
|
|
* @p: target task
|
|
* @preempt: whether task preemption is allowed or not
|
|
*
|
|
* It's the caller's job to ensure that the target task struct
|
|
* can't go away on us before we can do any checks.
|
|
*
|
|
* Returns true if we indeed boosted the target task.
|
|
*/
|
|
bool __sched yield_to(struct task_struct *p, bool preempt)
|
|
{
|
|
struct task_struct *curr = current;
|
|
struct rq *rq, *p_rq;
|
|
unsigned long flags;
|
|
bool yielded = 0;
|
|
|
|
local_irq_save(flags);
|
|
rq = this_rq();
|
|
|
|
again:
|
|
p_rq = task_rq(p);
|
|
double_rq_lock(rq, p_rq);
|
|
while (task_rq(p) != p_rq) {
|
|
double_rq_unlock(rq, p_rq);
|
|
goto again;
|
|
}
|
|
|
|
if (!curr->sched_class->yield_to_task)
|
|
goto out;
|
|
|
|
if (curr->sched_class != p->sched_class)
|
|
goto out;
|
|
|
|
if (task_running(p_rq, p) || p->state)
|
|
goto out;
|
|
|
|
yielded = curr->sched_class->yield_to_task(rq, p, preempt);
|
|
if (yielded) {
|
|
schedstat_inc(rq, yld_count);
|
|
/*
|
|
* Make p's CPU reschedule; pick_next_entity takes care of
|
|
* fairness.
|
|
*/
|
|
if (preempt && rq != p_rq)
|
|
resched_task(p_rq->curr);
|
|
} else {
|
|
/*
|
|
* We might have set it in task_yield_fair(), but are
|
|
* not going to schedule(), so don't want to skip
|
|
* the next update.
|
|
*/
|
|
rq->skip_clock_update = 0;
|
|
}
|
|
|
|
out:
|
|
double_rq_unlock(rq, p_rq);
|
|
local_irq_restore(flags);
|
|
|
|
if (yielded)
|
|
schedule();
|
|
|
|
return yielded;
|
|
}
|
|
EXPORT_SYMBOL_GPL(yield_to);
|
|
|
|
/*
|
|
* This task is about to go to sleep on IO. Increment rq->nr_iowait so
|
|
* that process accounting knows that this is a task in IO wait state.
|
|
*/
|
|
void __sched io_schedule(void)
|
|
{
|
|
struct rq *rq = raw_rq();
|
|
|
|
delayacct_blkio_start();
|
|
atomic_inc(&rq->nr_iowait);
|
|
blk_flush_plug(current);
|
|
current->in_iowait = 1;
|
|
schedule();
|
|
current->in_iowait = 0;
|
|
atomic_dec(&rq->nr_iowait);
|
|
delayacct_blkio_end();
|
|
}
|
|
EXPORT_SYMBOL(io_schedule);
|
|
|
|
long __sched io_schedule_timeout(long timeout)
|
|
{
|
|
struct rq *rq = raw_rq();
|
|
long ret;
|
|
|
|
delayacct_blkio_start();
|
|
atomic_inc(&rq->nr_iowait);
|
|
blk_flush_plug(current);
|
|
current->in_iowait = 1;
|
|
ret = schedule_timeout(timeout);
|
|
current->in_iowait = 0;
|
|
atomic_dec(&rq->nr_iowait);
|
|
delayacct_blkio_end();
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* sys_sched_get_priority_max - return maximum RT priority.
|
|
* @policy: scheduling class.
|
|
*
|
|
* this syscall returns the maximum rt_priority that can be used
|
|
* by a given scheduling class.
|
|
*/
|
|
SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
|
|
{
|
|
int ret = -EINVAL;
|
|
|
|
switch (policy) {
|
|
case SCHED_FIFO:
|
|
case SCHED_RR:
|
|
ret = MAX_USER_RT_PRIO-1;
|
|
break;
|
|
case SCHED_NORMAL:
|
|
case SCHED_BATCH:
|
|
case SCHED_IDLE:
|
|
ret = 0;
|
|
break;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* sys_sched_get_priority_min - return minimum RT priority.
|
|
* @policy: scheduling class.
|
|
*
|
|
* this syscall returns the minimum rt_priority that can be used
|
|
* by a given scheduling class.
|
|
*/
|
|
SYSCALL_DEFINE1(sched_get_priority_min, int, policy)
|
|
{
|
|
int ret = -EINVAL;
|
|
|
|
switch (policy) {
|
|
case SCHED_FIFO:
|
|
case SCHED_RR:
|
|
ret = 1;
|
|
break;
|
|
case SCHED_NORMAL:
|
|
case SCHED_BATCH:
|
|
case SCHED_IDLE:
|
|
ret = 0;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* sys_sched_rr_get_interval - return the default timeslice of a process.
|
|
* @pid: pid of the process.
|
|
* @interval: userspace pointer to the timeslice value.
|
|
*
|
|
* this syscall writes the default timeslice value of a given process
|
|
* into the user-space timespec buffer. A value of '0' means infinity.
|
|
*/
|
|
SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
|
|
struct timespec __user *, interval)
|
|
{
|
|
struct task_struct *p;
|
|
unsigned int time_slice;
|
|
unsigned long flags;
|
|
struct rq *rq;
|
|
int retval;
|
|
struct timespec t;
|
|
|
|
if (pid < 0)
|
|
return -EINVAL;
|
|
|
|
retval = -ESRCH;
|
|
rcu_read_lock();
|
|
p = find_process_by_pid(pid);
|
|
if (!p)
|
|
goto out_unlock;
|
|
|
|
retval = security_task_getscheduler(p);
|
|
if (retval)
|
|
goto out_unlock;
|
|
|
|
rq = task_rq_lock(p, &flags);
|
|
time_slice = p->sched_class->get_rr_interval(rq, p);
|
|
task_rq_unlock(rq, p, &flags);
|
|
|
|
rcu_read_unlock();
|
|
jiffies_to_timespec(time_slice, &t);
|
|
retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
|
|
return retval;
|
|
|
|
out_unlock:
|
|
rcu_read_unlock();
|
|
return retval;
|
|
}
|
|
|
|
static const char stat_nam[] = TASK_STATE_TO_CHAR_STR;
|
|
|
|
void sched_show_task(struct task_struct *p)
|
|
{
|
|
unsigned long free = 0;
|
|
unsigned state;
|
|
|
|
state = p->state ? __ffs(p->state) + 1 : 0;
|
|
printk(KERN_INFO "%-15.15s %c", p->comm,
|
|
state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
|
|
#if BITS_PER_LONG == 32
|
|
if (state == TASK_RUNNING)
|
|
printk(KERN_CONT " running ");
|
|
else
|
|
printk(KERN_CONT " %08lx ", thread_saved_pc(p));
|
|
#else
|
|
if (state == TASK_RUNNING)
|
|
printk(KERN_CONT " running task ");
|
|
else
|
|
printk(KERN_CONT " %016lx ", thread_saved_pc(p));
|
|
#endif
|
|
#ifdef CONFIG_DEBUG_STACK_USAGE
|
|
free = stack_not_used(p);
|
|
#endif
|
|
printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free,
|
|
task_pid_nr(p), task_pid_nr(rcu_dereference(p->real_parent)),
|
|
(unsigned long)task_thread_info(p)->flags);
|
|
|
|
show_stack(p, NULL);
|
|
}
|
|
|
|
void show_state_filter(unsigned long state_filter)
|
|
{
|
|
struct task_struct *g, *p;
|
|
|
|
#if BITS_PER_LONG == 32
|
|
printk(KERN_INFO
|
|
" task PC stack pid father\n");
|
|
#else
|
|
printk(KERN_INFO
|
|
" task PC stack pid father\n");
|
|
#endif
|
|
rcu_read_lock();
|
|
do_each_thread(g, p) {
|
|
/*
|
|
* reset the NMI-timeout, listing all files on a slow
|
|
* console might take a lot of time:
|
|
*/
|
|
touch_nmi_watchdog();
|
|
if (!state_filter || (p->state & state_filter))
|
|
sched_show_task(p);
|
|
} while_each_thread(g, p);
|
|
|
|
touch_all_softlockup_watchdogs();
|
|
|
|
#ifdef CONFIG_SCHED_DEBUG
|
|
sysrq_sched_debug_show();
|
|
#endif
|
|
rcu_read_unlock();
|
|
/*
|
|
* Only show locks if all tasks are dumped:
|
|
*/
|
|
if (!state_filter)
|
|
debug_show_all_locks();
|
|
}
|
|
|
|
void __cpuinit init_idle_bootup_task(struct task_struct *idle)
|
|
{
|
|
idle->sched_class = &idle_sched_class;
|
|
}
|
|
|
|
/**
|
|
* init_idle - set up an idle thread for a given CPU
|
|
* @idle: task in question
|
|
* @cpu: cpu the idle task belongs to
|
|
*
|
|
* NOTE: this function does not set the idle thread's NEED_RESCHED
|
|
* flag, to make booting more robust.
|
|
*/
|
|
void __cpuinit init_idle(struct task_struct *idle, int cpu)
|
|
{
|
|
struct rq *rq = cpu_rq(cpu);
|
|
unsigned long flags;
|
|
|
|
raw_spin_lock_irqsave(&rq->lock, flags);
|
|
|
|
__sched_fork(idle);
|
|
idle->state = TASK_RUNNING;
|
|
idle->se.exec_start = sched_clock();
|
|
|
|
do_set_cpus_allowed(idle, cpumask_of(cpu));
|
|
/*
|
|
* We're having a chicken and egg problem, even though we are
|
|
* holding rq->lock, the cpu isn't yet set to this cpu so the
|
|
* lockdep check in task_group() will fail.
|
|
*
|
|
* Similar case to sched_fork(). / Alternatively we could
|
|
* use task_rq_lock() here and obtain the other rq->lock.
|
|
*
|
|
* Silence PROVE_RCU
|
|
*/
|
|
rcu_read_lock();
|
|
__set_task_cpu(idle, cpu);
|
|
rcu_read_unlock();
|
|
|
|
rq->curr = rq->idle = idle;
|
|
#if defined(CONFIG_SMP)
|
|
idle->on_cpu = 1;
|
|
#endif
|
|
raw_spin_unlock_irqrestore(&rq->lock, flags);
|
|
|
|
/* Set the preempt count _outside_ the spinlocks! */
|
|
task_thread_info(idle)->preempt_count = 0;
|
|
|
|
/*
|
|
* The idle tasks have their own, simple scheduling class:
|
|
*/
|
|
idle->sched_class = &idle_sched_class;
|
|
ftrace_graph_init_idle_task(idle, cpu);
|
|
#if defined(CONFIG_SMP)
|
|
sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu);
|
|
#endif
|
|
}
|
|
|
|
#ifdef CONFIG_SMP
|
|
void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
|
|
{
|
|
if (p->sched_class && p->sched_class->set_cpus_allowed)
|
|
p->sched_class->set_cpus_allowed(p, new_mask);
|
|
|
|
cpumask_copy(&p->cpus_allowed, new_mask);
|
|
p->nr_cpus_allowed = cpumask_weight(new_mask);
|
|
}
|
|
|
|
/*
|
|
* This is how migration works:
|
|
*
|
|
* 1) we invoke migration_cpu_stop() on the target CPU using
|
|
* stop_one_cpu().
|
|
* 2) stopper starts to run (implicitly forcing the migrated thread
|
|
* off the CPU)
|
|
* 3) it checks whether the migrated task is still in the wrong runqueue.
|
|
* 4) if it's in the wrong runqueue then the migration thread removes
|
|
* it and puts it into the right queue.
|
|
* 5) stopper completes and stop_one_cpu() returns and the migration
|
|
* is done.
|
|
*/
|
|
|
|
/*
|
|
* Change a given task's CPU affinity. Migrate the thread to a
|
|
* proper CPU and schedule it away if the CPU it's executing on
|
|
* is removed from the allowed bitmask.
|
|
*
|
|
* NOTE: the caller must have a valid reference to the task, the
|
|
* task must not exit() & deallocate itself prematurely. The
|
|
* call is not atomic; no spinlocks may be held.
|
|
*/
|
|
int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
|
|
{
|
|
unsigned long flags;
|
|
struct rq *rq;
|
|
unsigned int dest_cpu;
|
|
int ret = 0;
|
|
|
|
rq = task_rq_lock(p, &flags);
|
|
|
|
if (cpumask_equal(&p->cpus_allowed, new_mask))
|
|
goto out;
|
|
|
|
if (!cpumask_intersects(new_mask, cpu_active_mask)) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
if (unlikely((p->flags & PF_THREAD_BOUND) && p != current)) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
do_set_cpus_allowed(p, new_mask);
|
|
|
|
/* Can the task run on the task's current CPU? If so, we're done */
|
|
if (cpumask_test_cpu(task_cpu(p), new_mask))
|
|
goto out;
|
|
|
|
dest_cpu = cpumask_any_and(cpu_active_mask, new_mask);
|
|
if (p->on_rq) {
|
|
struct migration_arg arg = { p, dest_cpu };
|
|
/* Need help from migration thread: drop lock and wait. */
|
|
task_rq_unlock(rq, p, &flags);
|
|
stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg);
|
|
tlb_migrate_finish(p->mm);
|
|
return 0;
|
|
}
|
|
out:
|
|
task_rq_unlock(rq, p, &flags);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
|
|
|
|
/*
|
|
* Move (not current) task off this cpu, onto dest cpu. We're doing
|
|
* this because either it can't run here any more (set_cpus_allowed()
|
|
* away from this CPU, or CPU going down), or because we're
|
|
* attempting to rebalance this task on exec (sched_exec).
|
|
*
|
|
* So we race with normal scheduler movements, but that's OK, as long
|
|
* as the task is no longer on this CPU.
|
|
*
|
|
* Returns non-zero if task was successfully migrated.
|
|
*/
|
|
static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
|
|
{
|
|
struct rq *rq_dest, *rq_src;
|
|
int ret = 0;
|
|
|
|
if (unlikely(!cpu_active(dest_cpu)))
|
|
return ret;
|
|
|
|
rq_src = cpu_rq(src_cpu);
|
|
rq_dest = cpu_rq(dest_cpu);
|
|
|
|
raw_spin_lock(&p->pi_lock);
|
|
double_rq_lock(rq_src, rq_dest);
|
|
/* Already moved. */
|
|
if (task_cpu(p) != src_cpu)
|
|
goto done;
|
|
/* Affinity changed (again). */
|
|
if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p)))
|
|
goto fail;
|
|
|
|
/*
|
|
* If we're not on a rq, the next wake-up will ensure we're
|
|
* placed properly.
|
|
*/
|
|
if (p->on_rq) {
|
|
dequeue_task(rq_src, p, 0);
|
|
set_task_cpu(p, dest_cpu);
|
|
enqueue_task(rq_dest, p, 0);
|
|
check_preempt_curr(rq_dest, p, 0);
|
|
}
|
|
done:
|
|
ret = 1;
|
|
fail:
|
|
double_rq_unlock(rq_src, rq_dest);
|
|
raw_spin_unlock(&p->pi_lock);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* migration_cpu_stop - this will be executed by a highprio stopper thread
|
|
* and performs thread migration by bumping thread off CPU then
|
|
* 'pushing' onto another runqueue.
|
|
*/
|
|
static int migration_cpu_stop(void *data)
|
|
{
|
|
struct migration_arg *arg = data;
|
|
|
|
/*
|
|
* The original target cpu might have gone down and we might
|
|
* be on another cpu but it doesn't matter.
|
|
*/
|
|
local_irq_disable();
|
|
__migrate_task(arg->task, raw_smp_processor_id(), arg->dest_cpu);
|
|
local_irq_enable();
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
|
|
/*
|
|
* Ensures that the idle task is using init_mm right before its cpu goes
|
|
* offline.
|
|
*/
|
|
void idle_task_exit(void)
|
|
{
|
|
struct mm_struct *mm = current->active_mm;
|
|
|
|
BUG_ON(cpu_online(smp_processor_id()));
|
|
|
|
if (mm != &init_mm)
|
|
switch_mm(mm, &init_mm, current);
|
|
mmdrop(mm);
|
|
}
|
|
|
|
/*
|
|
* While a dead CPU has no uninterruptible tasks queued at this point,
|
|
* it might still have a nonzero ->nr_uninterruptible counter, because
|
|
* for performance reasons the counter is not stricly tracking tasks to
|
|
* their home CPUs. So we just add the counter to another CPU's counter,
|
|
* to keep the global sum constant after CPU-down:
|
|
*/
|
|
static void migrate_nr_uninterruptible(struct rq *rq_src)
|
|
{
|
|
struct rq *rq_dest = cpu_rq(cpumask_any(cpu_active_mask));
|
|
|
|
rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible;
|
|
rq_src->nr_uninterruptible = 0;
|
|
}
|
|
|
|
/*
|
|
* remove the tasks which were accounted by rq from calc_load_tasks.
|
|
*/
|
|
static void calc_global_load_remove(struct rq *rq)
|
|
{
|
|
atomic_long_sub(rq->calc_load_active, &calc_load_tasks);
|
|
rq->calc_load_active = 0;
|
|
}
|
|
|
|
/*
|
|
* Migrate all tasks from the rq, sleeping tasks will be migrated by
|
|
* try_to_wake_up()->select_task_rq().
|
|
*
|
|
* Called with rq->lock held even though we'er in stop_machine() and
|
|
* there's no concurrency possible, we hold the required locks anyway
|
|
* because of lock validation efforts.
|
|
*/
|
|
static void migrate_tasks(unsigned int dead_cpu)
|
|
{
|
|
struct rq *rq = cpu_rq(dead_cpu);
|
|
struct task_struct *next, *stop = rq->stop;
|
|
int dest_cpu;
|
|
|
|
/*
|
|
* Fudge the rq selection such that the below task selection loop
|
|
* doesn't get stuck on the currently eligible stop task.
|
|
*
|
|
* We're currently inside stop_machine() and the rq is either stuck
|
|
* in the stop_machine_cpu_stop() loop, or we're executing this code,
|
|
* either way we should never end up calling schedule() until we're
|
|
* done here.
|
|
*/
|
|
rq->stop = NULL;
|
|
|
|
/* Ensure any throttled groups are reachable by pick_next_task */
|
|
unthrottle_offline_cfs_rqs(rq);
|
|
|
|
for ( ; ; ) {
|
|
/*
|
|
* There's this thread running, bail when that's the only
|
|
* remaining thread.
|
|
*/
|
|
if (rq->nr_running == 1)
|
|
break;
|
|
|
|
next = pick_next_task(rq);
|
|
BUG_ON(!next);
|
|
next->sched_class->put_prev_task(rq, next);
|
|
|
|
/* Find suitable destination for @next, with force if needed. */
|
|
dest_cpu = select_fallback_rq(dead_cpu, next);
|
|
raw_spin_unlock(&rq->lock);
|
|
|
|
__migrate_task(next, dead_cpu, dest_cpu);
|
|
|
|
raw_spin_lock(&rq->lock);
|
|
}
|
|
|
|
rq->stop = stop;
|
|
}
|
|
|
|
#endif /* CONFIG_HOTPLUG_CPU */
|
|
|
|
#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
|
|
|
|
static struct ctl_table sd_ctl_dir[] = {
|
|
{
|
|
.procname = "sched_domain",
|
|
.mode = 0555,
|
|
},
|
|
{}
|
|
};
|
|
|
|
static struct ctl_table sd_ctl_root[] = {
|
|
{
|
|
.procname = "kernel",
|
|
.mode = 0555,
|
|
.child = sd_ctl_dir,
|
|
},
|
|
{}
|
|
};
|
|
|
|
static struct ctl_table *sd_alloc_ctl_entry(int n)
|
|
{
|
|
struct ctl_table *entry =
|
|
kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL);
|
|
|
|
return entry;
|
|
}
|
|
|
|
static void sd_free_ctl_entry(struct ctl_table **tablep)
|
|
{
|
|
struct ctl_table *entry;
|
|
|
|
/*
|
|
* In the intermediate directories, both the child directory and
|
|
* procname are dynamically allocated and could fail but the mode
|
|
* will always be set. In the lowest directory the names are
|
|
* static strings and all have proc handlers.
|
|
*/
|
|
for (entry = *tablep; entry->mode; entry++) {
|
|
if (entry->child)
|
|
sd_free_ctl_entry(&entry->child);
|
|
if (entry->proc_handler == NULL)
|
|
kfree(entry->procname);
|
|
}
|
|
|
|
kfree(*tablep);
|
|
*tablep = NULL;
|
|
}
|
|
|
|
static void
|
|
set_table_entry(struct ctl_table *entry,
|
|
const char *procname, void *data, int maxlen,
|
|
umode_t mode, proc_handler *proc_handler)
|
|
{
|
|
entry->procname = procname;
|
|
entry->data = data;
|
|
entry->maxlen = maxlen;
|
|
entry->mode = mode;
|
|
entry->proc_handler = proc_handler;
|
|
}
|
|
|
|
static struct ctl_table *
|
|
sd_alloc_ctl_domain_table(struct sched_domain *sd)
|
|
{
|
|
struct ctl_table *table = sd_alloc_ctl_entry(13);
|
|
|
|
if (table == NULL)
|
|
return NULL;
|
|
|
|
set_table_entry(&table[0], "min_interval", &sd->min_interval,
|
|
sizeof(long), 0644, proc_doulongvec_minmax);
|
|
set_table_entry(&table[1], "max_interval", &sd->max_interval,
|
|
sizeof(long), 0644, proc_doulongvec_minmax);
|
|
set_table_entry(&table[2], "busy_idx", &sd->busy_idx,
|
|
sizeof(int), 0644, proc_dointvec_minmax);
|
|
set_table_entry(&table[3], "idle_idx", &sd->idle_idx,
|
|
sizeof(int), 0644, proc_dointvec_minmax);
|
|
set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx,
|
|
sizeof(int), 0644, proc_dointvec_minmax);
|
|
set_table_entry(&table[5], "wake_idx", &sd->wake_idx,
|
|
sizeof(int), 0644, proc_dointvec_minmax);
|
|
set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx,
|
|
sizeof(int), 0644, proc_dointvec_minmax);
|
|
set_table_entry(&table[7], "busy_factor", &sd->busy_factor,
|
|
sizeof(int), 0644, proc_dointvec_minmax);
|
|
set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct,
|
|
sizeof(int), 0644, proc_dointvec_minmax);
|
|
set_table_entry(&table[9], "cache_nice_tries",
|
|
&sd->cache_nice_tries,
|
|
sizeof(int), 0644, proc_dointvec_minmax);
|
|
set_table_entry(&table[10], "flags", &sd->flags,
|
|
sizeof(int), 0644, proc_dointvec_minmax);
|
|
set_table_entry(&table[11], "name", sd->name,
|
|
CORENAME_MAX_SIZE, 0444, proc_dostring);
|
|
/* &table[12] is terminator */
|
|
|
|
return table;
|
|
}
|
|
|
|
static ctl_table *sd_alloc_ctl_cpu_table(int cpu)
|
|
{
|
|
struct ctl_table *entry, *table;
|
|
struct sched_domain *sd;
|
|
int domain_num = 0, i;
|
|
char buf[32];
|
|
|
|
for_each_domain(cpu, sd)
|
|
domain_num++;
|
|
entry = table = sd_alloc_ctl_entry(domain_num + 1);
|
|
if (table == NULL)
|
|
return NULL;
|
|
|
|
i = 0;
|
|
for_each_domain(cpu, sd) {
|
|
snprintf(buf, 32, "domain%d", i);
|
|
entry->procname = kstrdup(buf, GFP_KERNEL);
|
|
entry->mode = 0555;
|
|
entry->child = sd_alloc_ctl_domain_table(sd);
|
|
entry++;
|
|
i++;
|
|
}
|
|
return table;
|
|
}
|
|
|
|
static struct ctl_table_header *sd_sysctl_header;
|
|
static void register_sched_domain_sysctl(void)
|
|
{
|
|
int i, cpu_num = num_possible_cpus();
|
|
struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
|
|
char buf[32];
|
|
|
|
WARN_ON(sd_ctl_dir[0].child);
|
|
sd_ctl_dir[0].child = entry;
|
|
|
|
if (entry == NULL)
|
|
return;
|
|
|
|
for_each_possible_cpu(i) {
|
|
snprintf(buf, 32, "cpu%d", i);
|
|
entry->procname = kstrdup(buf, GFP_KERNEL);
|
|
entry->mode = 0555;
|
|
entry->child = sd_alloc_ctl_cpu_table(i);
|
|
entry++;
|
|
}
|
|
|
|
WARN_ON(sd_sysctl_header);
|
|
sd_sysctl_header = register_sysctl_table(sd_ctl_root);
|
|
}
|
|
|
|
/* may be called multiple times per register */
|
|
static void unregister_sched_domain_sysctl(void)
|
|
{
|
|
if (sd_sysctl_header)
|
|
unregister_sysctl_table(sd_sysctl_header);
|
|
sd_sysctl_header = NULL;
|
|
if (sd_ctl_dir[0].child)
|
|
sd_free_ctl_entry(&sd_ctl_dir[0].child);
|
|
}
|
|
#else
|
|
static void register_sched_domain_sysctl(void)
|
|
{
|
|
}
|
|
static void unregister_sched_domain_sysctl(void)
|
|
{
|
|
}
|
|
#endif
|
|
|
|
static void set_rq_online(struct rq *rq)
|
|
{
|
|
if (!rq->online) {
|
|
const struct sched_class *class;
|
|
|
|
cpumask_set_cpu(rq->cpu, rq->rd->online);
|
|
rq->online = 1;
|
|
|
|
for_each_class(class) {
|
|
if (class->rq_online)
|
|
class->rq_online(rq);
|
|
}
|
|
}
|
|
}
|
|
|
|
static void set_rq_offline(struct rq *rq)
|
|
{
|
|
if (rq->online) {
|
|
const struct sched_class *class;
|
|
|
|
for_each_class(class) {
|
|
if (class->rq_offline)
|
|
class->rq_offline(rq);
|
|
}
|
|
|
|
cpumask_clear_cpu(rq->cpu, rq->rd->online);
|
|
rq->online = 0;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* migration_call - callback that gets triggered when a CPU is added.
|
|
* Here we can start up the necessary migration thread for the new CPU.
|
|
*/
|
|
static int __cpuinit
|
|
migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
|
|
{
|
|
int cpu = (long)hcpu;
|
|
unsigned long flags;
|
|
struct rq *rq = cpu_rq(cpu);
|
|
|
|
switch (action & ~CPU_TASKS_FROZEN) {
|
|
|
|
case CPU_UP_PREPARE:
|
|
rq->calc_load_update = calc_load_update;
|
|
break;
|
|
|
|
case CPU_ONLINE:
|
|
/* Update our root-domain */
|
|
raw_spin_lock_irqsave(&rq->lock, flags);
|
|
if (rq->rd) {
|
|
BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
|
|
|
|
set_rq_online(rq);
|
|
}
|
|
raw_spin_unlock_irqrestore(&rq->lock, flags);
|
|
break;
|
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
case CPU_DYING:
|
|
sched_ttwu_pending();
|
|
/* Update our root-domain */
|
|
raw_spin_lock_irqsave(&rq->lock, flags);
|
|
if (rq->rd) {
|
|
BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
|
|
set_rq_offline(rq);
|
|
}
|
|
migrate_tasks(cpu);
|
|
BUG_ON(rq->nr_running != 1); /* the migration thread */
|
|
raw_spin_unlock_irqrestore(&rq->lock, flags);
|
|
|
|
migrate_nr_uninterruptible(rq);
|
|
calc_global_load_remove(rq);
|
|
break;
|
|
#endif
|
|
}
|
|
|
|
update_max_interval();
|
|
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
/*
|
|
* Register at high priority so that task migration (migrate_all_tasks)
|
|
* happens before everything else. This has to be lower priority than
|
|
* the notifier in the perf_event subsystem, though.
|
|
*/
|
|
static struct notifier_block __cpuinitdata migration_notifier = {
|
|
.notifier_call = migration_call,
|
|
.priority = CPU_PRI_MIGRATION,
|
|
};
|
|
|
|
static int __cpuinit sched_cpu_active(struct notifier_block *nfb,
|
|
unsigned long action, void *hcpu)
|
|
{
|
|
switch (action & ~CPU_TASKS_FROZEN) {
|
|
case CPU_STARTING:
|
|
case CPU_DOWN_FAILED:
|
|
set_cpu_active((long)hcpu, true);
|
|
return NOTIFY_OK;
|
|
default:
|
|
return NOTIFY_DONE;
|
|
}
|
|
}
|
|
|
|
static int __cpuinit sched_cpu_inactive(struct notifier_block *nfb,
|
|
unsigned long action, void *hcpu)
|
|
{
|
|
switch (action & ~CPU_TASKS_FROZEN) {
|
|
case CPU_DOWN_PREPARE:
|
|
set_cpu_active((long)hcpu, false);
|
|
return NOTIFY_OK;
|
|
default:
|
|
return NOTIFY_DONE;
|
|
}
|
|
}
|
|
|
|
static int __init migration_init(void)
|
|
{
|
|
void *cpu = (void *)(long)smp_processor_id();
|
|
int err;
|
|
|
|
/* Initialize migration for the boot CPU */
|
|
err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
|
|
BUG_ON(err == NOTIFY_BAD);
|
|
migration_call(&migration_notifier, CPU_ONLINE, cpu);
|
|
register_cpu_notifier(&migration_notifier);
|
|
|
|
/* Register cpu active notifiers */
|
|
cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE);
|
|
cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE);
|
|
|
|
return 0;
|
|
}
|
|
early_initcall(migration_init);
|
|
#endif
|
|
|
|
#ifdef CONFIG_SMP
|
|
|
|
static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */
|
|
|
|
#ifdef CONFIG_SCHED_DEBUG
|
|
|
|
static __read_mostly int sched_debug_enabled;
|
|
|
|
static int __init sched_debug_setup(char *str)
|
|
{
|
|
sched_debug_enabled = 1;
|
|
|
|
return 0;
|
|
}
|
|
early_param("sched_debug", sched_debug_setup);
|
|
|
|
static inline bool sched_debug(void)
|
|
{
|
|
return sched_debug_enabled;
|
|
}
|
|
|
|
static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
|
|
struct cpumask *groupmask)
|
|
{
|
|
struct sched_group *group = sd->groups;
|
|
char str[256];
|
|
|
|
cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd));
|
|
cpumask_clear(groupmask);
|
|
|
|
printk(KERN_DEBUG "%*s domain %d: ", level, "", level);
|
|
|
|
if (!(sd->flags & SD_LOAD_BALANCE)) {
|
|
printk("does not load-balance\n");
|
|
if (sd->parent)
|
|
printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain"
|
|
" has parent");
|
|
return -1;
|
|
}
|
|
|
|
printk(KERN_CONT "span %s level %s\n", str, sd->name);
|
|
|
|
if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) {
|
|
printk(KERN_ERR "ERROR: domain->span does not contain "
|
|
"CPU%d\n", cpu);
|
|
}
|
|
if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) {
|
|
printk(KERN_ERR "ERROR: domain->groups does not contain"
|
|
" CPU%d\n", cpu);
|
|
}
|
|
|
|
printk(KERN_DEBUG "%*s groups:", level + 1, "");
|
|
do {
|
|
if (!group) {
|
|
printk("\n");
|
|
printk(KERN_ERR "ERROR: group is NULL\n");
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Even though we initialize ->power to something semi-sane,
|
|
* we leave power_orig unset. This allows us to detect if
|
|
* domain iteration is still funny without causing /0 traps.
|
|
*/
|
|
if (!group->sgp->power_orig) {
|
|
printk(KERN_CONT "\n");
|
|
printk(KERN_ERR "ERROR: domain->cpu_power not "
|
|
"set\n");
|
|
break;
|
|
}
|
|
|
|
if (!cpumask_weight(sched_group_cpus(group))) {
|
|
printk(KERN_CONT "\n");
|
|
printk(KERN_ERR "ERROR: empty group\n");
|
|
break;
|
|
}
|
|
|
|
if (!(sd->flags & SD_OVERLAP) &&
|
|
cpumask_intersects(groupmask, sched_group_cpus(group))) {
|
|
printk(KERN_CONT "\n");
|
|
printk(KERN_ERR "ERROR: repeated CPUs\n");
|
|
break;
|
|
}
|
|
|
|
cpumask_or(groupmask, groupmask, sched_group_cpus(group));
|
|
|
|
cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group));
|
|
|
|
printk(KERN_CONT " %s", str);
|
|
if (group->sgp->power != SCHED_POWER_SCALE) {
|
|
printk(KERN_CONT " (cpu_power = %d)",
|
|
group->sgp->power);
|
|
}
|
|
|
|
group = group->next;
|
|
} while (group != sd->groups);
|
|
printk(KERN_CONT "\n");
|
|
|
|
if (!cpumask_equal(sched_domain_span(sd), groupmask))
|
|
printk(KERN_ERR "ERROR: groups don't span domain->span\n");
|
|
|
|
if (sd->parent &&
|
|
!cpumask_subset(groupmask, sched_domain_span(sd->parent)))
|
|
printk(KERN_ERR "ERROR: parent span is not a superset "
|
|
"of domain->span\n");
|
|
return 0;
|
|
}
|
|
|
|
static void sched_domain_debug(struct sched_domain *sd, int cpu)
|
|
{
|
|
int level = 0;
|
|
|
|
if (!sched_debug_enabled)
|
|
return;
|
|
|
|
if (!sd) {
|
|
printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
|
|
return;
|
|
}
|
|
|
|
printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);
|
|
|
|
for (;;) {
|
|
if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask))
|
|
break;
|
|
level++;
|
|
sd = sd->parent;
|
|
if (!sd)
|
|
break;
|
|
}
|
|
}
|
|
#else /* !CONFIG_SCHED_DEBUG */
|
|
# define sched_domain_debug(sd, cpu) do { } while (0)
|
|
static inline bool sched_debug(void)
|
|
{
|
|
return false;
|
|
}
|
|
#endif /* CONFIG_SCHED_DEBUG */
|
|
|
|
static int sd_degenerate(struct sched_domain *sd)
|
|
{
|
|
if (cpumask_weight(sched_domain_span(sd)) == 1)
|
|
return 1;
|
|
|
|
/* Following flags need at least 2 groups */
|
|
if (sd->flags & (SD_LOAD_BALANCE |
|
|
SD_BALANCE_NEWIDLE |
|
|
SD_BALANCE_FORK |
|
|
SD_BALANCE_EXEC |
|
|
SD_SHARE_CPUPOWER |
|
|
SD_SHARE_PKG_RESOURCES)) {
|
|
if (sd->groups != sd->groups->next)
|
|
return 0;
|
|
}
|
|
|
|
/* Following flags don't use groups */
|
|
if (sd->flags & (SD_WAKE_AFFINE))
|
|
return 0;
|
|
|
|
return 1;
|
|
}
|
|
|
|
static int
|
|
sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
|
|
{
|
|
unsigned long cflags = sd->flags, pflags = parent->flags;
|
|
|
|
if (sd_degenerate(parent))
|
|
return 1;
|
|
|
|
if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent)))
|
|
return 0;
|
|
|
|
/* Flags needing groups don't count if only 1 group in parent */
|
|
if (parent->groups == parent->groups->next) {
|
|
pflags &= ~(SD_LOAD_BALANCE |
|
|
SD_BALANCE_NEWIDLE |
|
|
SD_BALANCE_FORK |
|
|
SD_BALANCE_EXEC |
|
|
SD_SHARE_CPUPOWER |
|
|
SD_SHARE_PKG_RESOURCES);
|
|
if (nr_node_ids == 1)
|
|
pflags &= ~SD_SERIALIZE;
|
|
}
|
|
if (~cflags & pflags)
|
|
return 0;
|
|
|
|
return 1;
|
|
}
|
|
|
|
static void free_rootdomain(struct rcu_head *rcu)
|
|
{
|
|
struct root_domain *rd = container_of(rcu, struct root_domain, rcu);
|
|
|
|
cpupri_cleanup(&rd->cpupri);
|
|
free_cpumask_var(rd->rto_mask);
|
|
free_cpumask_var(rd->online);
|
|
free_cpumask_var(rd->span);
|
|
kfree(rd);
|
|
}
|
|
|
|
static void rq_attach_root(struct rq *rq, struct root_domain *rd)
|
|
{
|
|
struct root_domain *old_rd = NULL;
|
|
unsigned long flags;
|
|
|
|
raw_spin_lock_irqsave(&rq->lock, flags);
|
|
|
|
if (rq->rd) {
|
|
old_rd = rq->rd;
|
|
|
|
if (cpumask_test_cpu(rq->cpu, old_rd->online))
|
|
set_rq_offline(rq);
|
|
|
|
cpumask_clear_cpu(rq->cpu, old_rd->span);
|
|
|
|
/*
|
|
* If we dont want to free the old_rt yet then
|
|
* set old_rd to NULL to skip the freeing later
|
|
* in this function:
|
|
*/
|
|
if (!atomic_dec_and_test(&old_rd->refcount))
|
|
old_rd = NULL;
|
|
}
|
|
|
|
atomic_inc(&rd->refcount);
|
|
rq->rd = rd;
|
|
|
|
cpumask_set_cpu(rq->cpu, rd->span);
|
|
if (cpumask_test_cpu(rq->cpu, cpu_active_mask))
|
|
set_rq_online(rq);
|
|
|
|
raw_spin_unlock_irqrestore(&rq->lock, flags);
|
|
|
|
if (old_rd)
|
|
call_rcu_sched(&old_rd->rcu, free_rootdomain);
|
|
}
|
|
|
|
static int init_rootdomain(struct root_domain *rd)
|
|
{
|
|
memset(rd, 0, sizeof(*rd));
|
|
|
|
if (!alloc_cpumask_var(&rd->span, GFP_KERNEL))
|
|
goto out;
|
|
if (!alloc_cpumask_var(&rd->online, GFP_KERNEL))
|
|
goto free_span;
|
|
if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
|
|
goto free_online;
|
|
|
|
if (cpupri_init(&rd->cpupri) != 0)
|
|
goto free_rto_mask;
|
|
return 0;
|
|
|
|
free_rto_mask:
|
|
free_cpumask_var(rd->rto_mask);
|
|
free_online:
|
|
free_cpumask_var(rd->online);
|
|
free_span:
|
|
free_cpumask_var(rd->span);
|
|
out:
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/*
|
|
* By default the system creates a single root-domain with all cpus as
|
|
* members (mimicking the global state we have today).
|
|
*/
|
|
struct root_domain def_root_domain;
|
|
|
|
static void init_defrootdomain(void)
|
|
{
|
|
init_rootdomain(&def_root_domain);
|
|
|
|
atomic_set(&def_root_domain.refcount, 1);
|
|
}
|
|
|
|
static struct root_domain *alloc_rootdomain(void)
|
|
{
|
|
struct root_domain *rd;
|
|
|
|
rd = kmalloc(sizeof(*rd), GFP_KERNEL);
|
|
if (!rd)
|
|
return NULL;
|
|
|
|
if (init_rootdomain(rd) != 0) {
|
|
kfree(rd);
|
|
return NULL;
|
|
}
|
|
|
|
return rd;
|
|
}
|
|
|
|
static void free_sched_groups(struct sched_group *sg, int free_sgp)
|
|
{
|
|
struct sched_group *tmp, *first;
|
|
|
|
if (!sg)
|
|
return;
|
|
|
|
first = sg;
|
|
do {
|
|
tmp = sg->next;
|
|
|
|
if (free_sgp && atomic_dec_and_test(&sg->sgp->ref))
|
|
kfree(sg->sgp);
|
|
|
|
kfree(sg);
|
|
sg = tmp;
|
|
} while (sg != first);
|
|
}
|
|
|
|
static void free_sched_domain(struct rcu_head *rcu)
|
|
{
|
|
struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu);
|
|
|
|
/*
|
|
* If its an overlapping domain it has private groups, iterate and
|
|
* nuke them all.
|
|
*/
|
|
if (sd->flags & SD_OVERLAP) {
|
|
free_sched_groups(sd->groups, 1);
|
|
} else if (atomic_dec_and_test(&sd->groups->ref)) {
|
|
kfree(sd->groups->sgp);
|
|
kfree(sd->groups);
|
|
}
|
|
kfree(sd);
|
|
}
|
|
|
|
static void destroy_sched_domain(struct sched_domain *sd, int cpu)
|
|
{
|
|
call_rcu(&sd->rcu, free_sched_domain);
|
|
}
|
|
|
|
static void destroy_sched_domains(struct sched_domain *sd, int cpu)
|
|
{
|
|
for (; sd; sd = sd->parent)
|
|
destroy_sched_domain(sd, cpu);
|
|
}
|
|
|
|
/*
|
|
* Keep a special pointer to the highest sched_domain that has
|
|
* SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
|
|
* allows us to avoid some pointer chasing select_idle_sibling().
|
|
*
|
|
* Iterate domains and sched_groups downward, assigning CPUs to be
|
|
* select_idle_sibling() hw buddy. Cross-wiring hw makes bouncing
|
|
* due to random perturbation self canceling, ie sw buddies pull
|
|
* their counterpart to their CPU's hw counterpart.
|
|
*
|
|
* Also keep a unique ID per domain (we use the first cpu number in
|
|
* the cpumask of the domain), this allows us to quickly tell if
|
|
* two cpus are in the same cache domain, see cpus_share_cache().
|
|
*/
|
|
DEFINE_PER_CPU(struct sched_domain *, sd_llc);
|
|
DEFINE_PER_CPU(int, sd_llc_id);
|
|
|
|
static void update_top_cache_domain(int cpu)
|
|
{
|
|
struct sched_domain *sd;
|
|
int id = cpu;
|
|
|
|
sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES);
|
|
if (sd) {
|
|
struct sched_domain *tmp = sd;
|
|
struct sched_group *sg, *prev;
|
|
bool right;
|
|
|
|
/*
|
|
* Traverse to first CPU in group, and count hops
|
|
* to cpu from there, switching direction on each
|
|
* hop, never ever pointing the last CPU rightward.
|
|
*/
|
|
do {
|
|
id = cpumask_first(sched_domain_span(tmp));
|
|
prev = sg = tmp->groups;
|
|
right = 1;
|
|
|
|
while (cpumask_first(sched_group_cpus(sg)) != id)
|
|
sg = sg->next;
|
|
|
|
while (!cpumask_test_cpu(cpu, sched_group_cpus(sg))) {
|
|
prev = sg;
|
|
sg = sg->next;
|
|
right = !right;
|
|
}
|
|
|
|
/* A CPU went down, never point back to domain start. */
|
|
if (right && cpumask_first(sched_group_cpus(sg->next)) == id)
|
|
right = false;
|
|
|
|
sg = right ? sg->next : prev;
|
|
tmp->idle_buddy = cpumask_first(sched_group_cpus(sg));
|
|
} while ((tmp = tmp->child));
|
|
|
|
id = cpumask_first(sched_domain_span(sd));
|
|
}
|
|
|
|
rcu_assign_pointer(per_cpu(sd_llc, cpu), sd);
|
|
per_cpu(sd_llc_id, cpu) = id;
|
|
}
|
|
|
|
/*
|
|
* Attach the domain 'sd' to 'cpu' as its base domain. Callers must
|
|
* hold the hotplug lock.
|
|
*/
|
|
static void
|
|
cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
|
|
{
|
|
struct rq *rq = cpu_rq(cpu);
|
|
struct sched_domain *tmp;
|
|
|
|
/* Remove the sched domains which do not contribute to scheduling. */
|
|
for (tmp = sd; tmp; ) {
|
|
struct sched_domain *parent = tmp->parent;
|
|
if (!parent)
|
|
break;
|
|
|
|
if (sd_parent_degenerate(tmp, parent)) {
|
|
tmp->parent = parent->parent;
|
|
if (parent->parent)
|
|
parent->parent->child = tmp;
|
|
destroy_sched_domain(parent, cpu);
|
|
} else
|
|
tmp = tmp->parent;
|
|
}
|
|
|
|
if (sd && sd_degenerate(sd)) {
|
|
tmp = sd;
|
|
sd = sd->parent;
|
|
destroy_sched_domain(tmp, cpu);
|
|
if (sd)
|
|
sd->child = NULL;
|
|
}
|
|
|
|
sched_domain_debug(sd, cpu);
|
|
|
|
rq_attach_root(rq, rd);
|
|
tmp = rq->sd;
|
|
rcu_assign_pointer(rq->sd, sd);
|
|
destroy_sched_domains(tmp, cpu);
|
|
|
|
update_top_cache_domain(cpu);
|
|
}
|
|
|
|
/* cpus with isolated domains */
|
|
static cpumask_var_t cpu_isolated_map;
|
|
|
|
/* Setup the mask of cpus configured for isolated domains */
|
|
static int __init isolated_cpu_setup(char *str)
|
|
{
|
|
alloc_bootmem_cpumask_var(&cpu_isolated_map);
|
|
cpulist_parse(str, cpu_isolated_map);
|
|
return 1;
|
|
}
|
|
|
|
__setup("isolcpus=", isolated_cpu_setup);
|
|
|
|
static const struct cpumask *cpu_cpu_mask(int cpu)
|
|
{
|
|
return cpumask_of_node(cpu_to_node(cpu));
|
|
}
|
|
|
|
struct sd_data {
|
|
struct sched_domain **__percpu sd;
|
|
struct sched_group **__percpu sg;
|
|
struct sched_group_power **__percpu sgp;
|
|
};
|
|
|
|
struct s_data {
|
|
struct sched_domain ** __percpu sd;
|
|
struct root_domain *rd;
|
|
};
|
|
|
|
enum s_alloc {
|
|
sa_rootdomain,
|
|
sa_sd,
|
|
sa_sd_storage,
|
|
sa_none,
|
|
};
|
|
|
|
struct sched_domain_topology_level;
|
|
|
|
typedef struct sched_domain *(*sched_domain_init_f)(struct sched_domain_topology_level *tl, int cpu);
|
|
typedef const struct cpumask *(*sched_domain_mask_f)(int cpu);
|
|
|
|
#define SDTL_OVERLAP 0x01
|
|
|
|
struct sched_domain_topology_level {
|
|
sched_domain_init_f init;
|
|
sched_domain_mask_f mask;
|
|
int flags;
|
|
int numa_level;
|
|
struct sd_data data;
|
|
};
|
|
|
|
/*
|
|
* Build an iteration mask that can exclude certain CPUs from the upwards
|
|
* domain traversal.
|
|
*
|
|
* Asymmetric node setups can result in situations where the domain tree is of
|
|
* unequal depth, make sure to skip domains that already cover the entire
|
|
* range.
|
|
*
|
|
* In that case build_sched_domains() will have terminated the iteration early
|
|
* and our sibling sd spans will be empty. Domains should always include the
|
|
* cpu they're built on, so check that.
|
|
*
|
|
*/
|
|
static void build_group_mask(struct sched_domain *sd, struct sched_group *sg)
|
|
{
|
|
const struct cpumask *span = sched_domain_span(sd);
|
|
struct sd_data *sdd = sd->private;
|
|
struct sched_domain *sibling;
|
|
int i;
|
|
|
|
for_each_cpu(i, span) {
|
|
sibling = *per_cpu_ptr(sdd->sd, i);
|
|
if (!cpumask_test_cpu(i, sched_domain_span(sibling)))
|
|
continue;
|
|
|
|
cpumask_set_cpu(i, sched_group_mask(sg));
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Return the canonical balance cpu for this group, this is the first cpu
|
|
* of this group that's also in the iteration mask.
|
|
*/
|
|
int group_balance_cpu(struct sched_group *sg)
|
|
{
|
|
return cpumask_first_and(sched_group_cpus(sg), sched_group_mask(sg));
|
|
}
|
|
|
|
static int
|
|
build_overlap_sched_groups(struct sched_domain *sd, int cpu)
|
|
{
|
|
struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg;
|
|
const struct cpumask *span = sched_domain_span(sd);
|
|
struct cpumask *covered = sched_domains_tmpmask;
|
|
struct sd_data *sdd = sd->private;
|
|
struct sched_domain *child;
|
|
int i;
|
|
|
|
cpumask_clear(covered);
|
|
|
|
for_each_cpu(i, span) {
|
|
struct cpumask *sg_span;
|
|
|
|
if (cpumask_test_cpu(i, covered))
|
|
continue;
|
|
|
|
child = *per_cpu_ptr(sdd->sd, i);
|
|
|
|
/* See the comment near build_group_mask(). */
|
|
if (!cpumask_test_cpu(i, sched_domain_span(child)))
|
|
continue;
|
|
|
|
sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
|
|
GFP_KERNEL, cpu_to_node(cpu));
|
|
|
|
if (!sg)
|
|
goto fail;
|
|
|
|
sg_span = sched_group_cpus(sg);
|
|
if (child->child) {
|
|
child = child->child;
|
|
cpumask_copy(sg_span, sched_domain_span(child));
|
|
} else
|
|
cpumask_set_cpu(i, sg_span);
|
|
|
|
cpumask_or(covered, covered, sg_span);
|
|
|
|
sg->sgp = *per_cpu_ptr(sdd->sgp, i);
|
|
if (atomic_inc_return(&sg->sgp->ref) == 1)
|
|
build_group_mask(sd, sg);
|
|
|
|
/*
|
|
* Initialize sgp->power such that even if we mess up the
|
|
* domains and no possible iteration will get us here, we won't
|
|
* die on a /0 trap.
|
|
*/
|
|
sg->sgp->power = SCHED_POWER_SCALE * cpumask_weight(sg_span);
|
|
|
|
/*
|
|
* Make sure the first group of this domain contains the
|
|
* canonical balance cpu. Otherwise the sched_domain iteration
|
|
* breaks. See update_sg_lb_stats().
|
|
*/
|
|
if ((!groups && cpumask_test_cpu(cpu, sg_span)) ||
|
|
group_balance_cpu(sg) == cpu)
|
|
groups = sg;
|
|
|
|
if (!first)
|
|
first = sg;
|
|
if (last)
|
|
last->next = sg;
|
|
last = sg;
|
|
last->next = first;
|
|
}
|
|
sd->groups = groups;
|
|
|
|
return 0;
|
|
|
|
fail:
|
|
free_sched_groups(first, 0);
|
|
|
|
return -ENOMEM;
|
|
}
|
|
|
|
static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg)
|
|
{
|
|
struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu);
|
|
struct sched_domain *child = sd->child;
|
|
|
|
if (child)
|
|
cpu = cpumask_first(sched_domain_span(child));
|
|
|
|
if (sg) {
|
|
*sg = *per_cpu_ptr(sdd->sg, cpu);
|
|
(*sg)->sgp = *per_cpu_ptr(sdd->sgp, cpu);
|
|
atomic_set(&(*sg)->sgp->ref, 1); /* for claim_allocations */
|
|
}
|
|
|
|
return cpu;
|
|
}
|
|
|
|
/*
|
|
* build_sched_groups will build a circular linked list of the groups
|
|
* covered by the given span, and will set each group's ->cpumask correctly,
|
|
* and ->cpu_power to 0.
|
|
*
|
|
* Assumes the sched_domain tree is fully constructed
|
|
*/
|
|
static int
|
|
build_sched_groups(struct sched_domain *sd, int cpu)
|
|
{
|
|
struct sched_group *first = NULL, *last = NULL;
|
|
struct sd_data *sdd = sd->private;
|
|
const struct cpumask *span = sched_domain_span(sd);
|
|
struct cpumask *covered;
|
|
int i;
|
|
|
|
get_group(cpu, sdd, &sd->groups);
|
|
atomic_inc(&sd->groups->ref);
|
|
|
|
if (cpu != cpumask_first(sched_domain_span(sd)))
|
|
return 0;
|
|
|
|
lockdep_assert_held(&sched_domains_mutex);
|
|
covered = sched_domains_tmpmask;
|
|
|
|
cpumask_clear(covered);
|
|
|
|
for_each_cpu(i, span) {
|
|
struct sched_group *sg;
|
|
int group = get_group(i, sdd, &sg);
|
|
int j;
|
|
|
|
if (cpumask_test_cpu(i, covered))
|
|
continue;
|
|
|
|
cpumask_clear(sched_group_cpus(sg));
|
|
sg->sgp->power = 0;
|
|
cpumask_setall(sched_group_mask(sg));
|
|
|
|
for_each_cpu(j, span) {
|
|
if (get_group(j, sdd, NULL) != group)
|
|
continue;
|
|
|
|
cpumask_set_cpu(j, covered);
|
|
cpumask_set_cpu(j, sched_group_cpus(sg));
|
|
}
|
|
|
|
if (!first)
|
|
first = sg;
|
|
if (last)
|
|
last->next = sg;
|
|
last = sg;
|
|
}
|
|
last->next = first;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Initialize sched groups cpu_power.
|
|
*
|
|
* cpu_power indicates the capacity of sched group, which is used while
|
|
* distributing the load between different sched groups in a sched domain.
|
|
* Typically cpu_power for all the groups in a sched domain will be same unless
|
|
* there are asymmetries in the topology. If there are asymmetries, group
|
|
* having more cpu_power will pickup more load compared to the group having
|
|
* less cpu_power.
|
|
*/
|
|
static void init_sched_groups_power(int cpu, struct sched_domain *sd)
|
|
{
|
|
struct sched_group *sg = sd->groups;
|
|
|
|
WARN_ON(!sd || !sg);
|
|
|
|
do {
|
|
sg->group_weight = cpumask_weight(sched_group_cpus(sg));
|
|
sg = sg->next;
|
|
} while (sg != sd->groups);
|
|
|
|
if (cpu != group_balance_cpu(sg))
|
|
return;
|
|
|
|
update_group_power(sd, cpu);
|
|
atomic_set(&sg->sgp->nr_busy_cpus, sg->group_weight);
|
|
}
|
|
|
|
int __weak arch_sd_sibling_asym_packing(void)
|
|
{
|
|
return 0*SD_ASYM_PACKING;
|
|
}
|
|
|
|
/*
|
|
* Initializers for schedule domains
|
|
* Non-inlined to reduce accumulated stack pressure in build_sched_domains()
|
|
*/
|
|
|
|
#ifdef CONFIG_SCHED_DEBUG
|
|
# define SD_INIT_NAME(sd, type) sd->name = #type
|
|
#else
|
|
# define SD_INIT_NAME(sd, type) do { } while (0)
|
|
#endif
|
|
|
|
#define SD_INIT_FUNC(type) \
|
|
static noinline struct sched_domain * \
|
|
sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \
|
|
{ \
|
|
struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \
|
|
*sd = SD_##type##_INIT; \
|
|
SD_INIT_NAME(sd, type); \
|
|
sd->private = &tl->data; \
|
|
return sd; \
|
|
}
|
|
|
|
SD_INIT_FUNC(CPU)
|
|
#ifdef CONFIG_SCHED_SMT
|
|
SD_INIT_FUNC(SIBLING)
|
|
#endif
|
|
#ifdef CONFIG_SCHED_MC
|
|
SD_INIT_FUNC(MC)
|
|
#endif
|
|
#ifdef CONFIG_SCHED_BOOK
|
|
SD_INIT_FUNC(BOOK)
|
|
#endif
|
|
|
|
static int default_relax_domain_level = -1;
|
|
int sched_domain_level_max;
|
|
|
|
static int __init setup_relax_domain_level(char *str)
|
|
{
|
|
if (kstrtoint(str, 0, &default_relax_domain_level))
|
|
pr_warn("Unable to set relax_domain_level\n");
|
|
|
|
return 1;
|
|
}
|
|
__setup("relax_domain_level=", setup_relax_domain_level);
|
|
|
|
static void set_domain_attribute(struct sched_domain *sd,
|
|
struct sched_domain_attr *attr)
|
|
{
|
|
int request;
|
|
|
|
if (!attr || attr->relax_domain_level < 0) {
|
|
if (default_relax_domain_level < 0)
|
|
return;
|
|
else
|
|
request = default_relax_domain_level;
|
|
} else
|
|
request = attr->relax_domain_level;
|
|
if (request < sd->level) {
|
|
/* turn off idle balance on this domain */
|
|
sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
|
|
} else {
|
|
/* turn on idle balance on this domain */
|
|
sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
|
|
}
|
|
}
|
|
|
|
static void __sdt_free(const struct cpumask *cpu_map);
|
|
static int __sdt_alloc(const struct cpumask *cpu_map);
|
|
|
|
static void __free_domain_allocs(struct s_data *d, enum s_alloc what,
|
|
const struct cpumask *cpu_map)
|
|
{
|
|
switch (what) {
|
|
case sa_rootdomain:
|
|
if (!atomic_read(&d->rd->refcount))
|
|
free_rootdomain(&d->rd->rcu); /* fall through */
|
|
case sa_sd:
|
|
free_percpu(d->sd); /* fall through */
|
|
case sa_sd_storage:
|
|
__sdt_free(cpu_map); /* fall through */
|
|
case sa_none:
|
|
break;
|
|
}
|
|
}
|
|
|
|
static enum s_alloc __visit_domain_allocation_hell(struct s_data *d,
|
|
const struct cpumask *cpu_map)
|
|
{
|
|
memset(d, 0, sizeof(*d));
|
|
|
|
if (__sdt_alloc(cpu_map))
|
|
return sa_sd_storage;
|
|
d->sd = alloc_percpu(struct sched_domain *);
|
|
if (!d->sd)
|
|
return sa_sd_storage;
|
|
d->rd = alloc_rootdomain();
|
|
if (!d->rd)
|
|
return sa_sd;
|
|
return sa_rootdomain;
|
|
}
|
|
|
|
/*
|
|
* NULL the sd_data elements we've used to build the sched_domain and
|
|
* sched_group structure so that the subsequent __free_domain_allocs()
|
|
* will not free the data we're using.
|
|
*/
|
|
static void claim_allocations(int cpu, struct sched_domain *sd)
|
|
{
|
|
struct sd_data *sdd = sd->private;
|
|
|
|
WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd);
|
|
*per_cpu_ptr(sdd->sd, cpu) = NULL;
|
|
|
|
if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref))
|
|
*per_cpu_ptr(sdd->sg, cpu) = NULL;
|
|
|
|
if (atomic_read(&(*per_cpu_ptr(sdd->sgp, cpu))->ref))
|
|
*per_cpu_ptr(sdd->sgp, cpu) = NULL;
|
|
}
|
|
|
|
#ifdef CONFIG_SCHED_SMT
|
|
static const struct cpumask *cpu_smt_mask(int cpu)
|
|
{
|
|
return topology_thread_cpumask(cpu);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Topology list, bottom-up.
|
|
*/
|
|
static struct sched_domain_topology_level default_topology[] = {
|
|
#ifdef CONFIG_SCHED_SMT
|
|
{ sd_init_SIBLING, cpu_smt_mask, },
|
|
#endif
|
|
#ifdef CONFIG_SCHED_MC
|
|
{ sd_init_MC, cpu_coregroup_mask, },
|
|
#endif
|
|
#ifdef CONFIG_SCHED_BOOK
|
|
{ sd_init_BOOK, cpu_book_mask, },
|
|
#endif
|
|
{ sd_init_CPU, cpu_cpu_mask, },
|
|
{ NULL, },
|
|
};
|
|
|
|
static struct sched_domain_topology_level *sched_domain_topology = default_topology;
|
|
|
|
#ifdef CONFIG_NUMA
|
|
|
|
static int sched_domains_numa_levels;
|
|
static int *sched_domains_numa_distance;
|
|
static struct cpumask ***sched_domains_numa_masks;
|
|
static int sched_domains_curr_level;
|
|
|
|
static inline int sd_local_flags(int level)
|
|
{
|
|
if (sched_domains_numa_distance[level] > RECLAIM_DISTANCE)
|
|
return 0;
|
|
|
|
return SD_BALANCE_EXEC | SD_BALANCE_FORK | SD_WAKE_AFFINE;
|
|
}
|
|
|
|
static struct sched_domain *
|
|
sd_numa_init(struct sched_domain_topology_level *tl, int cpu)
|
|
{
|
|
struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu);
|
|
int level = tl->numa_level;
|
|
int sd_weight = cpumask_weight(
|
|
sched_domains_numa_masks[level][cpu_to_node(cpu)]);
|
|
|
|
*sd = (struct sched_domain){
|
|
.min_interval = sd_weight,
|
|
.max_interval = 2*sd_weight,
|
|
.busy_factor = 32,
|
|
.imbalance_pct = 125,
|
|
.cache_nice_tries = 2,
|
|
.busy_idx = 3,
|
|
.idle_idx = 2,
|
|
.newidle_idx = 0,
|
|
.wake_idx = 0,
|
|
.forkexec_idx = 0,
|
|
|
|
.flags = 1*SD_LOAD_BALANCE
|
|
| 1*SD_BALANCE_NEWIDLE
|
|
| 0*SD_BALANCE_EXEC
|
|
| 0*SD_BALANCE_FORK
|
|
| 0*SD_BALANCE_WAKE
|
|
| 0*SD_WAKE_AFFINE
|
|
| 0*SD_PREFER_LOCAL
|
|
| 0*SD_SHARE_CPUPOWER
|
|
| 0*SD_SHARE_PKG_RESOURCES
|
|
| 1*SD_SERIALIZE
|
|
| 0*SD_PREFER_SIBLING
|
|
| sd_local_flags(level)
|
|
,
|
|
.last_balance = jiffies,
|
|
.balance_interval = sd_weight,
|
|
};
|
|
SD_INIT_NAME(sd, NUMA);
|
|
sd->private = &tl->data;
|
|
|
|
/*
|
|
* Ugly hack to pass state to sd_numa_mask()...
|
|
*/
|
|
sched_domains_curr_level = tl->numa_level;
|
|
|
|
return sd;
|
|
}
|
|
|
|
static const struct cpumask *sd_numa_mask(int cpu)
|
|
{
|
|
return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)];
|
|
}
|
|
|
|
static void sched_numa_warn(const char *str)
|
|
{
|
|
static int done = false;
|
|
int i,j;
|
|
|
|
if (done)
|
|
return;
|
|
|
|
done = true;
|
|
|
|
printk(KERN_WARNING "ERROR: %s\n\n", str);
|
|
|
|
for (i = 0; i < nr_node_ids; i++) {
|
|
printk(KERN_WARNING " ");
|
|
for (j = 0; j < nr_node_ids; j++)
|
|
printk(KERN_CONT "%02d ", node_distance(i,j));
|
|
printk(KERN_CONT "\n");
|
|
}
|
|
printk(KERN_WARNING "\n");
|
|
}
|
|
|
|
static bool find_numa_distance(int distance)
|
|
{
|
|
int i;
|
|
|
|
if (distance == node_distance(0, 0))
|
|
return true;
|
|
|
|
for (i = 0; i < sched_domains_numa_levels; i++) {
|
|
if (sched_domains_numa_distance[i] == distance)
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
static void sched_init_numa(void)
|
|
{
|
|
int next_distance, curr_distance = node_distance(0, 0);
|
|
struct sched_domain_topology_level *tl;
|
|
int level = 0;
|
|
int i, j, k;
|
|
|
|
sched_domains_numa_distance = kzalloc(sizeof(int) * nr_node_ids, GFP_KERNEL);
|
|
if (!sched_domains_numa_distance)
|
|
return;
|
|
|
|
/*
|
|
* O(nr_nodes^2) deduplicating selection sort -- in order to find the
|
|
* unique distances in the node_distance() table.
|
|
*
|
|
* Assumes node_distance(0,j) includes all distances in
|
|
* node_distance(i,j) in order to avoid cubic time.
|
|
*/
|
|
next_distance = curr_distance;
|
|
for (i = 0; i < nr_node_ids; i++) {
|
|
for (j = 0; j < nr_node_ids; j++) {
|
|
for (k = 0; k < nr_node_ids; k++) {
|
|
int distance = node_distance(i, k);
|
|
|
|
if (distance > curr_distance &&
|
|
(distance < next_distance ||
|
|
next_distance == curr_distance))
|
|
next_distance = distance;
|
|
|
|
/*
|
|
* While not a strong assumption it would be nice to know
|
|
* about cases where if node A is connected to B, B is not
|
|
* equally connected to A.
|
|
*/
|
|
if (sched_debug() && node_distance(k, i) != distance)
|
|
sched_numa_warn("Node-distance not symmetric");
|
|
|
|
if (sched_debug() && i && !find_numa_distance(distance))
|
|
sched_numa_warn("Node-0 not representative");
|
|
}
|
|
if (next_distance != curr_distance) {
|
|
sched_domains_numa_distance[level++] = next_distance;
|
|
sched_domains_numa_levels = level;
|
|
curr_distance = next_distance;
|
|
} else break;
|
|
}
|
|
|
|
/*
|
|
* In case of sched_debug() we verify the above assumption.
|
|
*/
|
|
if (!sched_debug())
|
|
break;
|
|
}
|
|
/*
|
|
* 'level' contains the number of unique distances, excluding the
|
|
* identity distance node_distance(i,i).
|
|
*
|
|
* The sched_domains_nume_distance[] array includes the actual distance
|
|
* numbers.
|
|
*/
|
|
|
|
sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL);
|
|
if (!sched_domains_numa_masks)
|
|
return;
|
|
|
|
/*
|
|
* Now for each level, construct a mask per node which contains all
|
|
* cpus of nodes that are that many hops away from us.
|
|
*/
|
|
for (i = 0; i < level; i++) {
|
|
sched_domains_numa_masks[i] =
|
|
kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL);
|
|
if (!sched_domains_numa_masks[i])
|
|
return;
|
|
|
|
for (j = 0; j < nr_node_ids; j++) {
|
|
struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL);
|
|
if (!mask)
|
|
return;
|
|
|
|
sched_domains_numa_masks[i][j] = mask;
|
|
|
|
for (k = 0; k < nr_node_ids; k++) {
|
|
if (node_distance(j, k) > sched_domains_numa_distance[i])
|
|
continue;
|
|
|
|
cpumask_or(mask, mask, cpumask_of_node(k));
|
|
}
|
|
}
|
|
}
|
|
|
|
tl = kzalloc((ARRAY_SIZE(default_topology) + level) *
|
|
sizeof(struct sched_domain_topology_level), GFP_KERNEL);
|
|
if (!tl)
|
|
return;
|
|
|
|
/*
|
|
* Copy the default topology bits..
|
|
*/
|
|
for (i = 0; default_topology[i].init; i++)
|
|
tl[i] = default_topology[i];
|
|
|
|
/*
|
|
* .. and append 'j' levels of NUMA goodness.
|
|
*/
|
|
for (j = 0; j < level; i++, j++) {
|
|
tl[i] = (struct sched_domain_topology_level){
|
|
.init = sd_numa_init,
|
|
.mask = sd_numa_mask,
|
|
.flags = SDTL_OVERLAP,
|
|
.numa_level = j,
|
|
};
|
|
}
|
|
|
|
sched_domain_topology = tl;
|
|
}
|
|
#else
|
|
static inline void sched_init_numa(void)
|
|
{
|
|
}
|
|
#endif /* CONFIG_NUMA */
|
|
|
|
static int __sdt_alloc(const struct cpumask *cpu_map)
|
|
{
|
|
struct sched_domain_topology_level *tl;
|
|
int j;
|
|
|
|
for (tl = sched_domain_topology; tl->init; tl++) {
|
|
struct sd_data *sdd = &tl->data;
|
|
|
|
sdd->sd = alloc_percpu(struct sched_domain *);
|
|
if (!sdd->sd)
|
|
return -ENOMEM;
|
|
|
|
sdd->sg = alloc_percpu(struct sched_group *);
|
|
if (!sdd->sg)
|
|
return -ENOMEM;
|
|
|
|
sdd->sgp = alloc_percpu(struct sched_group_power *);
|
|
if (!sdd->sgp)
|
|
return -ENOMEM;
|
|
|
|
for_each_cpu(j, cpu_map) {
|
|
struct sched_domain *sd;
|
|
struct sched_group *sg;
|
|
struct sched_group_power *sgp;
|
|
|
|
sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(),
|
|
GFP_KERNEL, cpu_to_node(j));
|
|
if (!sd)
|
|
return -ENOMEM;
|
|
|
|
*per_cpu_ptr(sdd->sd, j) = sd;
|
|
|
|
sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
|
|
GFP_KERNEL, cpu_to_node(j));
|
|
if (!sg)
|
|
return -ENOMEM;
|
|
|
|
sg->next = sg;
|
|
|
|
*per_cpu_ptr(sdd->sg, j) = sg;
|
|
|
|
sgp = kzalloc_node(sizeof(struct sched_group_power) + cpumask_size(),
|
|
GFP_KERNEL, cpu_to_node(j));
|
|
if (!sgp)
|
|
return -ENOMEM;
|
|
|
|
*per_cpu_ptr(sdd->sgp, j) = sgp;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void __sdt_free(const struct cpumask *cpu_map)
|
|
{
|
|
struct sched_domain_topology_level *tl;
|
|
int j;
|
|
|
|
for (tl = sched_domain_topology; tl->init; tl++) {
|
|
struct sd_data *sdd = &tl->data;
|
|
|
|
for_each_cpu(j, cpu_map) {
|
|
struct sched_domain *sd;
|
|
|
|
if (sdd->sd) {
|
|
sd = *per_cpu_ptr(sdd->sd, j);
|
|
if (sd && (sd->flags & SD_OVERLAP))
|
|
free_sched_groups(sd->groups, 0);
|
|
kfree(*per_cpu_ptr(sdd->sd, j));
|
|
}
|
|
|
|
if (sdd->sg)
|
|
kfree(*per_cpu_ptr(sdd->sg, j));
|
|
if (sdd->sgp)
|
|
kfree(*per_cpu_ptr(sdd->sgp, j));
|
|
}
|
|
free_percpu(sdd->sd);
|
|
sdd->sd = NULL;
|
|
free_percpu(sdd->sg);
|
|
sdd->sg = NULL;
|
|
free_percpu(sdd->sgp);
|
|
sdd->sgp = NULL;
|
|
}
|
|
}
|
|
|
|
struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl,
|
|
struct s_data *d, const struct cpumask *cpu_map,
|
|
struct sched_domain_attr *attr, struct sched_domain *child,
|
|
int cpu)
|
|
{
|
|
struct sched_domain *sd = tl->init(tl, cpu);
|
|
if (!sd)
|
|
return child;
|
|
|
|
cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu));
|
|
if (child) {
|
|
sd->level = child->level + 1;
|
|
sched_domain_level_max = max(sched_domain_level_max, sd->level);
|
|
child->parent = sd;
|
|
}
|
|
sd->child = child;
|
|
set_domain_attribute(sd, attr);
|
|
|
|
return sd;
|
|
}
|
|
|
|
/*
|
|
* Build sched domains for a given set of cpus and attach the sched domains
|
|
* to the individual cpus
|
|
*/
|
|
static int build_sched_domains(const struct cpumask *cpu_map,
|
|
struct sched_domain_attr *attr)
|
|
{
|
|
enum s_alloc alloc_state = sa_none;
|
|
struct sched_domain *sd;
|
|
struct s_data d;
|
|
int i, ret = -ENOMEM;
|
|
|
|
alloc_state = __visit_domain_allocation_hell(&d, cpu_map);
|
|
if (alloc_state != sa_rootdomain)
|
|
goto error;
|
|
|
|
/* Set up domains for cpus specified by the cpu_map. */
|
|
for_each_cpu(i, cpu_map) {
|
|
struct sched_domain_topology_level *tl;
|
|
|
|
sd = NULL;
|
|
for (tl = sched_domain_topology; tl->init; tl++) {
|
|
sd = build_sched_domain(tl, &d, cpu_map, attr, sd, i);
|
|
if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP))
|
|
sd->flags |= SD_OVERLAP;
|
|
if (cpumask_equal(cpu_map, sched_domain_span(sd)))
|
|
break;
|
|
}
|
|
|
|
while (sd->child)
|
|
sd = sd->child;
|
|
|
|
*per_cpu_ptr(d.sd, i) = sd;
|
|
}
|
|
|
|
/* Build the groups for the domains */
|
|
for_each_cpu(i, cpu_map) {
|
|
for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
|
|
sd->span_weight = cpumask_weight(sched_domain_span(sd));
|
|
if (sd->flags & SD_OVERLAP) {
|
|
if (build_overlap_sched_groups(sd, i))
|
|
goto error;
|
|
} else {
|
|
if (build_sched_groups(sd, i))
|
|
goto error;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Calculate CPU power for physical packages and nodes */
|
|
for (i = nr_cpumask_bits-1; i >= 0; i--) {
|
|
if (!cpumask_test_cpu(i, cpu_map))
|
|
continue;
|
|
|
|
for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
|
|
claim_allocations(i, sd);
|
|
init_sched_groups_power(i, sd);
|
|
}
|
|
}
|
|
|
|
/* Attach the domains */
|
|
rcu_read_lock();
|
|
for_each_cpu(i, cpu_map) {
|
|
sd = *per_cpu_ptr(d.sd, i);
|
|
cpu_attach_domain(sd, d.rd, i);
|
|
}
|
|
rcu_read_unlock();
|
|
|
|
ret = 0;
|
|
error:
|
|
__free_domain_allocs(&d, alloc_state, cpu_map);
|
|
return ret;
|
|
}
|
|
|
|
static cpumask_var_t *doms_cur; /* current sched domains */
|
|
static int ndoms_cur; /* number of sched domains in 'doms_cur' */
|
|
static struct sched_domain_attr *dattr_cur;
|
|
/* attribues of custom domains in 'doms_cur' */
|
|
|
|
/*
|
|
* Special case: If a kmalloc of a doms_cur partition (array of
|
|
* cpumask) fails, then fallback to a single sched domain,
|
|
* as determined by the single cpumask fallback_doms.
|
|
*/
|
|
static cpumask_var_t fallback_doms;
|
|
|
|
/*
|
|
* arch_update_cpu_topology lets virtualized architectures update the
|
|
* cpu core maps. It is supposed to return 1 if the topology changed
|
|
* or 0 if it stayed the same.
|
|
*/
|
|
int __attribute__((weak)) arch_update_cpu_topology(void)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
cpumask_var_t *alloc_sched_domains(unsigned int ndoms)
|
|
{
|
|
int i;
|
|
cpumask_var_t *doms;
|
|
|
|
doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL);
|
|
if (!doms)
|
|
return NULL;
|
|
for (i = 0; i < ndoms; i++) {
|
|
if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) {
|
|
free_sched_domains(doms, i);
|
|
return NULL;
|
|
}
|
|
}
|
|
return doms;
|
|
}
|
|
|
|
void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms)
|
|
{
|
|
unsigned int i;
|
|
for (i = 0; i < ndoms; i++)
|
|
free_cpumask_var(doms[i]);
|
|
kfree(doms);
|
|
}
|
|
|
|
/*
|
|
* Set up scheduler domains and groups. Callers must hold the hotplug lock.
|
|
* For now this just excludes isolated cpus, but could be used to
|
|
* exclude other special cases in the future.
|
|
*/
|
|
static int init_sched_domains(const struct cpumask *cpu_map)
|
|
{
|
|
int err;
|
|
|
|
arch_update_cpu_topology();
|
|
ndoms_cur = 1;
|
|
doms_cur = alloc_sched_domains(ndoms_cur);
|
|
if (!doms_cur)
|
|
doms_cur = &fallback_doms;
|
|
cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map);
|
|
err = build_sched_domains(doms_cur[0], NULL);
|
|
register_sched_domain_sysctl();
|
|
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* Detach sched domains from a group of cpus specified in cpu_map
|
|
* These cpus will now be attached to the NULL domain
|
|
*/
|
|
static void detach_destroy_domains(const struct cpumask *cpu_map)
|
|
{
|
|
int i;
|
|
|
|
rcu_read_lock();
|
|
for_each_cpu(i, cpu_map)
|
|
cpu_attach_domain(NULL, &def_root_domain, i);
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
/* handle null as "default" */
|
|
static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
|
|
struct sched_domain_attr *new, int idx_new)
|
|
{
|
|
struct sched_domain_attr tmp;
|
|
|
|
/* fast path */
|
|
if (!new && !cur)
|
|
return 1;
|
|
|
|
tmp = SD_ATTR_INIT;
|
|
return !memcmp(cur ? (cur + idx_cur) : &tmp,
|
|
new ? (new + idx_new) : &tmp,
|
|
sizeof(struct sched_domain_attr));
|
|
}
|
|
|
|
/*
|
|
* Partition sched domains as specified by the 'ndoms_new'
|
|
* cpumasks in the array doms_new[] of cpumasks. This compares
|
|
* doms_new[] to the current sched domain partitioning, doms_cur[].
|
|
* It destroys each deleted domain and builds each new domain.
|
|
*
|
|
* 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
|
|
* The masks don't intersect (don't overlap.) We should setup one
|
|
* sched domain for each mask. CPUs not in any of the cpumasks will
|
|
* not be load balanced. If the same cpumask appears both in the
|
|
* current 'doms_cur' domains and in the new 'doms_new', we can leave
|
|
* it as it is.
|
|
*
|
|
* The passed in 'doms_new' should be allocated using
|
|
* alloc_sched_domains. This routine takes ownership of it and will
|
|
* free_sched_domains it when done with it. If the caller failed the
|
|
* alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
|
|
* and partition_sched_domains() will fallback to the single partition
|
|
* 'fallback_doms', it also forces the domains to be rebuilt.
|
|
*
|
|
* If doms_new == NULL it will be replaced with cpu_online_mask.
|
|
* ndoms_new == 0 is a special case for destroying existing domains,
|
|
* and it will not create the default domain.
|
|
*
|
|
* Call with hotplug lock held
|
|
*/
|
|
void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
|
|
struct sched_domain_attr *dattr_new)
|
|
{
|
|
int i, j, n;
|
|
int new_topology;
|
|
|
|
mutex_lock(&sched_domains_mutex);
|
|
|
|
/* always unregister in case we don't destroy any domains */
|
|
unregister_sched_domain_sysctl();
|
|
|
|
/* Let architecture update cpu core mappings. */
|
|
new_topology = arch_update_cpu_topology();
|
|
|
|
n = doms_new ? ndoms_new : 0;
|
|
|
|
/* Destroy deleted domains */
|
|
for (i = 0; i < ndoms_cur; i++) {
|
|
for (j = 0; j < n && !new_topology; j++) {
|
|
if (cpumask_equal(doms_cur[i], doms_new[j])
|
|
&& dattrs_equal(dattr_cur, i, dattr_new, j))
|
|
goto match1;
|
|
}
|
|
/* no match - a current sched domain not in new doms_new[] */
|
|
detach_destroy_domains(doms_cur[i]);
|
|
match1:
|
|
;
|
|
}
|
|
|
|
if (doms_new == NULL) {
|
|
ndoms_cur = 0;
|
|
doms_new = &fallback_doms;
|
|
cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map);
|
|
WARN_ON_ONCE(dattr_new);
|
|
}
|
|
|
|
/* Build new domains */
|
|
for (i = 0; i < ndoms_new; i++) {
|
|
for (j = 0; j < ndoms_cur && !new_topology; j++) {
|
|
if (cpumask_equal(doms_new[i], doms_cur[j])
|
|
&& dattrs_equal(dattr_new, i, dattr_cur, j))
|
|
goto match2;
|
|
}
|
|
/* no match - add a new doms_new */
|
|
build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL);
|
|
match2:
|
|
;
|
|
}
|
|
|
|
/* Remember the new sched domains */
|
|
if (doms_cur != &fallback_doms)
|
|
free_sched_domains(doms_cur, ndoms_cur);
|
|
kfree(dattr_cur); /* kfree(NULL) is safe */
|
|
doms_cur = doms_new;
|
|
dattr_cur = dattr_new;
|
|
ndoms_cur = ndoms_new;
|
|
|
|
register_sched_domain_sysctl();
|
|
|
|
mutex_unlock(&sched_domains_mutex);
|
|
}
|
|
|
|
static int num_cpus_frozen; /* used to mark begin/end of suspend/resume */
|
|
|
|
/*
|
|
* Update cpusets according to cpu_active mask. If cpusets are
|
|
* disabled, cpuset_update_active_cpus() becomes a simple wrapper
|
|
* around partition_sched_domains().
|
|
*
|
|
* If we come here as part of a suspend/resume, don't touch cpusets because we
|
|
* want to restore it back to its original state upon resume anyway.
|
|
*/
|
|
static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action,
|
|
void *hcpu)
|
|
{
|
|
switch (action) {
|
|
case CPU_ONLINE_FROZEN:
|
|
case CPU_DOWN_FAILED_FROZEN:
|
|
|
|
/*
|
|
* num_cpus_frozen tracks how many CPUs are involved in suspend
|
|
* resume sequence. As long as this is not the last online
|
|
* operation in the resume sequence, just build a single sched
|
|
* domain, ignoring cpusets.
|
|
*/
|
|
num_cpus_frozen--;
|
|
if (likely(num_cpus_frozen)) {
|
|
partition_sched_domains(1, NULL, NULL);
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* This is the last CPU online operation. So fall through and
|
|
* restore the original sched domains by considering the
|
|
* cpuset configurations.
|
|
*/
|
|
|
|
case CPU_ONLINE:
|
|
case CPU_DOWN_FAILED:
|
|
cpuset_update_active_cpus(true);
|
|
break;
|
|
default:
|
|
return NOTIFY_DONE;
|
|
}
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action,
|
|
void *hcpu)
|
|
{
|
|
switch (action) {
|
|
case CPU_DOWN_PREPARE:
|
|
cpuset_update_active_cpus(false);
|
|
break;
|
|
case CPU_DOWN_PREPARE_FROZEN:
|
|
num_cpus_frozen++;
|
|
partition_sched_domains(1, NULL, NULL);
|
|
break;
|
|
default:
|
|
return NOTIFY_DONE;
|
|
}
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
void __init sched_init_smp(void)
|
|
{
|
|
cpumask_var_t non_isolated_cpus;
|
|
|
|
alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL);
|
|
alloc_cpumask_var(&fallback_doms, GFP_KERNEL);
|
|
|
|
sched_init_numa();
|
|
|
|
get_online_cpus();
|
|
mutex_lock(&sched_domains_mutex);
|
|
init_sched_domains(cpu_active_mask);
|
|
cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map);
|
|
if (cpumask_empty(non_isolated_cpus))
|
|
cpumask_set_cpu(smp_processor_id(), non_isolated_cpus);
|
|
mutex_unlock(&sched_domains_mutex);
|
|
put_online_cpus();
|
|
|
|
hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE);
|
|
hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE);
|
|
|
|
/* RT runtime code needs to handle some hotplug events */
|
|
hotcpu_notifier(update_runtime, 0);
|
|
|
|
init_hrtick();
|
|
|
|
/* Move init over to a non-isolated CPU */
|
|
if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0)
|
|
BUG();
|
|
sched_init_granularity();
|
|
free_cpumask_var(non_isolated_cpus);
|
|
|
|
init_sched_rt_class();
|
|
}
|
|
#else
|
|
void __init sched_init_smp(void)
|
|
{
|
|
sched_init_granularity();
|
|
}
|
|
#endif /* CONFIG_SMP */
|
|
|
|
const_debug unsigned int sysctl_timer_migration = 1;
|
|
|
|
int in_sched_functions(unsigned long addr)
|
|
{
|
|
return in_lock_functions(addr) ||
|
|
(addr >= (unsigned long)__sched_text_start
|
|
&& addr < (unsigned long)__sched_text_end);
|
|
}
|
|
|
|
#ifdef CONFIG_CGROUP_SCHED
|
|
struct task_group root_task_group;
|
|
#endif
|
|
|
|
DECLARE_PER_CPU(cpumask_var_t, load_balance_tmpmask);
|
|
|
|
void __init sched_init(void)
|
|
{
|
|
int i, j;
|
|
unsigned long alloc_size = 0, ptr;
|
|
|
|
#ifdef CONFIG_FAIR_GROUP_SCHED
|
|
alloc_size += 2 * nr_cpu_ids * sizeof(void **);
|
|
#endif
|
|
#ifdef CONFIG_RT_GROUP_SCHED
|
|
alloc_size += 2 * nr_cpu_ids * sizeof(void **);
|
|
#endif
|
|
#ifdef CONFIG_CPUMASK_OFFSTACK
|
|
alloc_size += num_possible_cpus() * cpumask_size();
|
|
#endif
|
|
if (alloc_size) {
|
|
ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT);
|
|
|
|
#ifdef CONFIG_FAIR_GROUP_SCHED
|
|
root_task_group.se = (struct sched_entity **)ptr;
|
|
ptr += nr_cpu_ids * sizeof(void **);
|
|
|
|
root_task_group.cfs_rq = (struct cfs_rq **)ptr;
|
|
ptr += nr_cpu_ids * sizeof(void **);
|
|
|
|
#endif /* CONFIG_FAIR_GROUP_SCHED */
|
|
#ifdef CONFIG_RT_GROUP_SCHED
|
|
root_task_group.rt_se = (struct sched_rt_entity **)ptr;
|
|
ptr += nr_cpu_ids * sizeof(void **);
|
|
|
|
root_task_group.rt_rq = (struct rt_rq **)ptr;
|
|
ptr += nr_cpu_ids * sizeof(void **);
|
|
|
|
#endif /* CONFIG_RT_GROUP_SCHED */
|
|
#ifdef CONFIG_CPUMASK_OFFSTACK
|
|
for_each_possible_cpu(i) {
|
|
per_cpu(load_balance_tmpmask, i) = (void *)ptr;
|
|
ptr += cpumask_size();
|
|
}
|
|
#endif /* CONFIG_CPUMASK_OFFSTACK */
|
|
}
|
|
|
|
#ifdef CONFIG_SMP
|
|
init_defrootdomain();
|
|
#endif
|
|
|
|
init_rt_bandwidth(&def_rt_bandwidth,
|
|
global_rt_period(), global_rt_runtime());
|
|
|
|
#ifdef CONFIG_RT_GROUP_SCHED
|
|
init_rt_bandwidth(&root_task_group.rt_bandwidth,
|
|
global_rt_period(), global_rt_runtime());
|
|
#endif /* CONFIG_RT_GROUP_SCHED */
|
|
|
|
#ifdef CONFIG_CGROUP_SCHED
|
|
list_add(&root_task_group.list, &task_groups);
|
|
INIT_LIST_HEAD(&root_task_group.children);
|
|
INIT_LIST_HEAD(&root_task_group.siblings);
|
|
autogroup_init(&init_task);
|
|
|
|
#endif /* CONFIG_CGROUP_SCHED */
|
|
|
|
#ifdef CONFIG_CGROUP_CPUACCT
|
|
root_cpuacct.cpustat = &kernel_cpustat;
|
|
root_cpuacct.cpuusage = alloc_percpu(u64);
|
|
/* Too early, not expected to fail */
|
|
BUG_ON(!root_cpuacct.cpuusage);
|
|
#endif
|
|
for_each_possible_cpu(i) {
|
|
struct rq *rq;
|
|
|
|
rq = cpu_rq(i);
|
|
raw_spin_lock_init(&rq->lock);
|
|
rq->nr_running = 0;
|
|
rq->calc_load_active = 0;
|
|
rq->calc_load_update = jiffies + LOAD_FREQ;
|
|
init_cfs_rq(&rq->cfs);
|
|
init_rt_rq(&rq->rt, rq);
|
|
#ifdef CONFIG_FAIR_GROUP_SCHED
|
|
root_task_group.shares = ROOT_TASK_GROUP_LOAD;
|
|
INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
|
|
/*
|
|
* How much cpu bandwidth does root_task_group get?
|
|
*
|
|
* In case of task-groups formed thr' the cgroup filesystem, it
|
|
* gets 100% of the cpu resources in the system. This overall
|
|
* system cpu resource is divided among the tasks of
|
|
* root_task_group and its child task-groups in a fair manner,
|
|
* based on each entity's (task or task-group's) weight
|
|
* (se->load.weight).
|
|
*
|
|
* In other words, if root_task_group has 10 tasks of weight
|
|
* 1024) and two child groups A0 and A1 (of weight 1024 each),
|
|
* then A0's share of the cpu resource is:
|
|
*
|
|
* A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
|
|
*
|
|
* We achieve this by letting root_task_group's tasks sit
|
|
* directly in rq->cfs (i.e root_task_group->se[] = NULL).
|
|
*/
|
|
init_cfs_bandwidth(&root_task_group.cfs_bandwidth);
|
|
init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL);
|
|
#endif /* CONFIG_FAIR_GROUP_SCHED */
|
|
|
|
rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
|
|
#ifdef CONFIG_RT_GROUP_SCHED
|
|
INIT_LIST_HEAD(&rq->leaf_rt_rq_list);
|
|
init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL);
|
|
#endif
|
|
|
|
for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
|
|
rq->cpu_load[j] = 0;
|
|
|
|
rq->last_load_update_tick = jiffies;
|
|
|
|
#ifdef CONFIG_SMP
|
|
rq->sd = NULL;
|
|
rq->rd = NULL;
|
|
rq->cpu_power = SCHED_POWER_SCALE;
|
|
rq->post_schedule = 0;
|
|
rq->active_balance = 0;
|
|
rq->next_balance = jiffies;
|
|
rq->push_cpu = 0;
|
|
rq->cpu = i;
|
|
rq->online = 0;
|
|
rq->idle_stamp = 0;
|
|
rq->avg_idle = 2*sysctl_sched_migration_cost;
|
|
|
|
INIT_LIST_HEAD(&rq->cfs_tasks);
|
|
|
|
rq_attach_root(rq, &def_root_domain);
|
|
#ifdef CONFIG_NO_HZ
|
|
rq->nohz_flags = 0;
|
|
#endif
|
|
#endif
|
|
init_rq_hrtick(rq);
|
|
atomic_set(&rq->nr_iowait, 0);
|
|
}
|
|
|
|
set_load_weight(&init_task);
|
|
|
|
#ifdef CONFIG_PREEMPT_NOTIFIERS
|
|
INIT_HLIST_HEAD(&init_task.preempt_notifiers);
|
|
#endif
|
|
|
|
#ifdef CONFIG_RT_MUTEXES
|
|
plist_head_init(&init_task.pi_waiters);
|
|
#endif
|
|
|
|
/*
|
|
* The boot idle thread does lazy MMU switching as well:
|
|
*/
|
|
atomic_inc(&init_mm.mm_count);
|
|
enter_lazy_tlb(&init_mm, current);
|
|
|
|
/*
|
|
* Make us the idle thread. Technically, schedule() should not be
|
|
* called from this thread, however somewhere below it might be,
|
|
* but because we are the idle thread, we just pick up running again
|
|
* when this runqueue becomes "idle".
|
|
*/
|
|
init_idle(current, smp_processor_id());
|
|
|
|
calc_load_update = jiffies + LOAD_FREQ;
|
|
|
|
/*
|
|
* During early bootup we pretend to be a normal task:
|
|
*/
|
|
current->sched_class = &fair_sched_class;
|
|
|
|
#ifdef CONFIG_SMP
|
|
zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT);
|
|
/* May be allocated at isolcpus cmdline parse time */
|
|
if (cpu_isolated_map == NULL)
|
|
zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
|
|
idle_thread_set_boot_cpu();
|
|
#endif
|
|
init_sched_fair_class();
|
|
|
|
scheduler_running = 1;
|
|
}
|
|
|
|
#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
|
|
static inline int preempt_count_equals(int preempt_offset)
|
|
{
|
|
int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth();
|
|
|
|
return (nested == preempt_offset);
|
|
}
|
|
|
|
void __might_sleep(const char *file, int line, int preempt_offset)
|
|
{
|
|
static unsigned long prev_jiffy; /* ratelimiting */
|
|
|
|
rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
|
|
if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) ||
|
|
system_state != SYSTEM_RUNNING || oops_in_progress)
|
|
return;
|
|
if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
|
|
return;
|
|
prev_jiffy = jiffies;
|
|
|
|
printk(KERN_ERR
|
|
"BUG: sleeping function called from invalid context at %s:%d\n",
|
|
file, line);
|
|
printk(KERN_ERR
|
|
"in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
|
|
in_atomic(), irqs_disabled(),
|
|
current->pid, current->comm);
|
|
|
|
debug_show_held_locks(current);
|
|
if (irqs_disabled())
|
|
print_irqtrace_events(current);
|
|
dump_stack();
|
|
}
|
|
EXPORT_SYMBOL(__might_sleep);
|
|
#endif
|
|
|
|
#ifdef CONFIG_MAGIC_SYSRQ
|
|
static void normalize_task(struct rq *rq, struct task_struct *p)
|
|
{
|
|
const struct sched_class *prev_class = p->sched_class;
|
|
int old_prio = p->prio;
|
|
int on_rq;
|
|
|
|
on_rq = p->on_rq;
|
|
if (on_rq)
|
|
dequeue_task(rq, p, 0);
|
|
__setscheduler(rq, p, SCHED_NORMAL, 0);
|
|
if (on_rq) {
|
|
enqueue_task(rq, p, 0);
|
|
resched_task(rq->curr);
|
|
}
|
|
|
|
check_class_changed(rq, p, prev_class, old_prio);
|
|
}
|
|
|
|
void normalize_rt_tasks(void)
|
|
{
|
|
struct task_struct *g, *p;
|
|
unsigned long flags;
|
|
struct rq *rq;
|
|
|
|
read_lock_irqsave(&tasklist_lock, flags);
|
|
do_each_thread(g, p) {
|
|
/*
|
|
* Only normalize user tasks:
|
|
*/
|
|
if (!p->mm)
|
|
continue;
|
|
|
|
p->se.exec_start = 0;
|
|
#ifdef CONFIG_SCHEDSTATS
|
|
p->se.statistics.wait_start = 0;
|
|
p->se.statistics.sleep_start = 0;
|
|
p->se.statistics.block_start = 0;
|
|
#endif
|
|
|
|
if (!rt_task(p)) {
|
|
/*
|
|
* Renice negative nice level userspace
|
|
* tasks back to 0:
|
|
*/
|
|
if (TASK_NICE(p) < 0 && p->mm)
|
|
set_user_nice(p, 0);
|
|
continue;
|
|
}
|
|
|
|
raw_spin_lock(&p->pi_lock);
|
|
rq = __task_rq_lock(p);
|
|
|
|
normalize_task(rq, p);
|
|
|
|
__task_rq_unlock(rq);
|
|
raw_spin_unlock(&p->pi_lock);
|
|
} while_each_thread(g, p);
|
|
|
|
read_unlock_irqrestore(&tasklist_lock, flags);
|
|
}
|
|
|
|
#endif /* CONFIG_MAGIC_SYSRQ */
|
|
|
|
#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
|
|
/*
|
|
* These functions are only useful for the IA64 MCA handling, or kdb.
|
|
*
|
|
* They can only be called when the whole system has been
|
|
* stopped - every CPU needs to be quiescent, and no scheduling
|
|
* activity can take place. Using them for anything else would
|
|
* be a serious bug, and as a result, they aren't even visible
|
|
* under any other configuration.
|
|
*/
|
|
|
|
/**
|
|
* curr_task - return the current task for a given cpu.
|
|
* @cpu: the processor in question.
|
|
*
|
|
* ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
|
|
*/
|
|
struct task_struct *curr_task(int cpu)
|
|
{
|
|
return cpu_curr(cpu);
|
|
}
|
|
|
|
#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
|
|
|
|
#ifdef CONFIG_IA64
|
|
/**
|
|
* set_curr_task - set the current task for a given cpu.
|
|
* @cpu: the processor in question.
|
|
* @p: the task pointer to set.
|
|
*
|
|
* Description: This function must only be used when non-maskable interrupts
|
|
* are serviced on a separate stack. It allows the architecture to switch the
|
|
* notion of the current task on a cpu in a non-blocking manner. This function
|
|
* must be called with all CPU's synchronized, and interrupts disabled, the
|
|
* and caller must save the original value of the current task (see
|
|
* curr_task() above) and restore that value before reenabling interrupts and
|
|
* re-starting the system.
|
|
*
|
|
* ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
|
|
*/
|
|
void set_curr_task(int cpu, struct task_struct *p)
|
|
{
|
|
cpu_curr(cpu) = p;
|
|
}
|
|
|
|
#endif
|
|
|
|
#ifdef CONFIG_CGROUP_SCHED
|
|
/* task_group_lock serializes the addition/removal of task groups */
|
|
static DEFINE_SPINLOCK(task_group_lock);
|
|
|
|
static void free_sched_group(struct task_group *tg)
|
|
{
|
|
free_fair_sched_group(tg);
|
|
free_rt_sched_group(tg);
|
|
autogroup_free(tg);
|
|
kfree(tg);
|
|
}
|
|
|
|
/* allocate runqueue etc for a new task group */
|
|
struct task_group *sched_create_group(struct task_group *parent)
|
|
{
|
|
struct task_group *tg;
|
|
unsigned long flags;
|
|
|
|
tg = kzalloc(sizeof(*tg), GFP_KERNEL);
|
|
if (!tg)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
if (!alloc_fair_sched_group(tg, parent))
|
|
goto err;
|
|
|
|
if (!alloc_rt_sched_group(tg, parent))
|
|
goto err;
|
|
|
|
spin_lock_irqsave(&task_group_lock, flags);
|
|
list_add_rcu(&tg->list, &task_groups);
|
|
|
|
WARN_ON(!parent); /* root should already exist */
|
|
|
|
tg->parent = parent;
|
|
INIT_LIST_HEAD(&tg->children);
|
|
list_add_rcu(&tg->siblings, &parent->children);
|
|
spin_unlock_irqrestore(&task_group_lock, flags);
|
|
|
|
return tg;
|
|
|
|
err:
|
|
free_sched_group(tg);
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
/* rcu callback to free various structures associated with a task group */
|
|
static void free_sched_group_rcu(struct rcu_head *rhp)
|
|
{
|
|
/* now it should be safe to free those cfs_rqs */
|
|
free_sched_group(container_of(rhp, struct task_group, rcu));
|
|
}
|
|
|
|
/* Destroy runqueue etc associated with a task group */
|
|
void sched_destroy_group(struct task_group *tg)
|
|
{
|
|
unsigned long flags;
|
|
int i;
|
|
|
|
/* end participation in shares distribution */
|
|
for_each_possible_cpu(i)
|
|
unregister_fair_sched_group(tg, i);
|
|
|
|
spin_lock_irqsave(&task_group_lock, flags);
|
|
list_del_rcu(&tg->list);
|
|
list_del_rcu(&tg->siblings);
|
|
spin_unlock_irqrestore(&task_group_lock, flags);
|
|
|
|
/* wait for possible concurrent references to cfs_rqs complete */
|
|
call_rcu(&tg->rcu, free_sched_group_rcu);
|
|
}
|
|
|
|
/* change task's runqueue when it moves between groups.
|
|
* The caller of this function should have put the task in its new group
|
|
* by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
|
|
* reflect its new group.
|
|
*/
|
|
void sched_move_task(struct task_struct *tsk)
|
|
{
|
|
struct task_group *tg;
|
|
int on_rq, running;
|
|
unsigned long flags;
|
|
struct rq *rq;
|
|
|
|
rq = task_rq_lock(tsk, &flags);
|
|
|
|
running = task_current(rq, tsk);
|
|
on_rq = tsk->on_rq;
|
|
|
|
if (on_rq)
|
|
dequeue_task(rq, tsk, 0);
|
|
if (unlikely(running))
|
|
tsk->sched_class->put_prev_task(rq, tsk);
|
|
|
|
tg = container_of(task_subsys_state_check(tsk, cpu_cgroup_subsys_id,
|
|
lockdep_is_held(&tsk->sighand->siglock)),
|
|
struct task_group, css);
|
|
tg = autogroup_task_group(tsk, tg);
|
|
tsk->sched_task_group = tg;
|
|
|
|
#ifdef CONFIG_FAIR_GROUP_SCHED
|
|
if (tsk->sched_class->task_move_group)
|
|
tsk->sched_class->task_move_group(tsk, on_rq);
|
|
else
|
|
#endif
|
|
set_task_rq(tsk, task_cpu(tsk));
|
|
|
|
if (unlikely(running))
|
|
tsk->sched_class->set_curr_task(rq);
|
|
if (on_rq)
|
|
enqueue_task(rq, tsk, 0);
|
|
|
|
task_rq_unlock(rq, tsk, &flags);
|
|
}
|
|
#endif /* CONFIG_CGROUP_SCHED */
|
|
|
|
#if defined(CONFIG_RT_GROUP_SCHED) || defined(CONFIG_CFS_BANDWIDTH)
|
|
static unsigned long to_ratio(u64 period, u64 runtime)
|
|
{
|
|
if (runtime == RUNTIME_INF)
|
|
return 1ULL << 20;
|
|
|
|
return div64_u64(runtime << 20, period);
|
|
}
|
|
#endif
|
|
|
|
#ifdef CONFIG_RT_GROUP_SCHED
|
|
/*
|
|
* Ensure that the real time constraints are schedulable.
|
|
*/
|
|
static DEFINE_MUTEX(rt_constraints_mutex);
|
|
|
|
/* Must be called with tasklist_lock held */
|
|
static inline int tg_has_rt_tasks(struct task_group *tg)
|
|
{
|
|
struct task_struct *g, *p;
|
|
|
|
do_each_thread(g, p) {
|
|
if (rt_task(p) && task_rq(p)->rt.tg == tg)
|
|
return 1;
|
|
} while_each_thread(g, p);
|
|
|
|
return 0;
|
|
}
|
|
|
|
struct rt_schedulable_data {
|
|
struct task_group *tg;
|
|
u64 rt_period;
|
|
u64 rt_runtime;
|
|
};
|
|
|
|
static int tg_rt_schedulable(struct task_group *tg, void *data)
|
|
{
|
|
struct rt_schedulable_data *d = data;
|
|
struct task_group *child;
|
|
unsigned long total, sum = 0;
|
|
u64 period, runtime;
|
|
|
|
period = ktime_to_ns(tg->rt_bandwidth.rt_period);
|
|
runtime = tg->rt_bandwidth.rt_runtime;
|
|
|
|
if (tg == d->tg) {
|
|
period = d->rt_period;
|
|
runtime = d->rt_runtime;
|
|
}
|
|
|
|
/*
|
|
* Cannot have more runtime than the period.
|
|
*/
|
|
if (runtime > period && runtime != RUNTIME_INF)
|
|
return -EINVAL;
|
|
|
|
/*
|
|
* Ensure we don't starve existing RT tasks.
|
|
*/
|
|
if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg))
|
|
return -EBUSY;
|
|
|
|
total = to_ratio(period, runtime);
|
|
|
|
/*
|
|
* Nobody can have more than the global setting allows.
|
|
*/
|
|
if (total > to_ratio(global_rt_period(), global_rt_runtime()))
|
|
return -EINVAL;
|
|
|
|
/*
|
|
* The sum of our children's runtime should not exceed our own.
|
|
*/
|
|
list_for_each_entry_rcu(child, &tg->children, siblings) {
|
|
period = ktime_to_ns(child->rt_bandwidth.rt_period);
|
|
runtime = child->rt_bandwidth.rt_runtime;
|
|
|
|
if (child == d->tg) {
|
|
period = d->rt_period;
|
|
runtime = d->rt_runtime;
|
|
}
|
|
|
|
sum += to_ratio(period, runtime);
|
|
}
|
|
|
|
if (sum > total)
|
|
return -EINVAL;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
|
|
{
|
|
int ret;
|
|
|
|
struct rt_schedulable_data data = {
|
|
.tg = tg,
|
|
.rt_period = period,
|
|
.rt_runtime = runtime,
|
|
};
|
|
|
|
rcu_read_lock();
|
|
ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data);
|
|
rcu_read_unlock();
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int tg_set_rt_bandwidth(struct task_group *tg,
|
|
u64 rt_period, u64 rt_runtime)
|
|
{
|
|
int i, err = 0;
|
|
|
|
mutex_lock(&rt_constraints_mutex);
|
|
read_lock(&tasklist_lock);
|
|
err = __rt_schedulable(tg, rt_period, rt_runtime);
|
|
if (err)
|
|
goto unlock;
|
|
|
|
raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock);
|
|
tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period);
|
|
tg->rt_bandwidth.rt_runtime = rt_runtime;
|
|
|
|
for_each_possible_cpu(i) {
|
|
struct rt_rq *rt_rq = tg->rt_rq[i];
|
|
|
|
raw_spin_lock(&rt_rq->rt_runtime_lock);
|
|
rt_rq->rt_runtime = rt_runtime;
|
|
raw_spin_unlock(&rt_rq->rt_runtime_lock);
|
|
}
|
|
raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock);
|
|
unlock:
|
|
read_unlock(&tasklist_lock);
|
|
mutex_unlock(&rt_constraints_mutex);
|
|
|
|
return err;
|
|
}
|
|
|
|
int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
|
|
{
|
|
u64 rt_runtime, rt_period;
|
|
|
|
rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
|
|
rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
|
|
if (rt_runtime_us < 0)
|
|
rt_runtime = RUNTIME_INF;
|
|
|
|
return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
|
|
}
|
|
|
|
long sched_group_rt_runtime(struct task_group *tg)
|
|
{
|
|
u64 rt_runtime_us;
|
|
|
|
if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF)
|
|
return -1;
|
|
|
|
rt_runtime_us = tg->rt_bandwidth.rt_runtime;
|
|
do_div(rt_runtime_us, NSEC_PER_USEC);
|
|
return rt_runtime_us;
|
|
}
|
|
|
|
int sched_group_set_rt_period(struct task_group *tg, long rt_period_us)
|
|
{
|
|
u64 rt_runtime, rt_period;
|
|
|
|
rt_period = (u64)rt_period_us * NSEC_PER_USEC;
|
|
rt_runtime = tg->rt_bandwidth.rt_runtime;
|
|
|
|
if (rt_period == 0)
|
|
return -EINVAL;
|
|
|
|
return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
|
|
}
|
|
|
|
long sched_group_rt_period(struct task_group *tg)
|
|
{
|
|
u64 rt_period_us;
|
|
|
|
rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period);
|
|
do_div(rt_period_us, NSEC_PER_USEC);
|
|
return rt_period_us;
|
|
}
|
|
|
|
static int sched_rt_global_constraints(void)
|
|
{
|
|
u64 runtime, period;
|
|
int ret = 0;
|
|
|
|
if (sysctl_sched_rt_period <= 0)
|
|
return -EINVAL;
|
|
|
|
runtime = global_rt_runtime();
|
|
period = global_rt_period();
|
|
|
|
/*
|
|
* Sanity check on the sysctl variables.
|
|
*/
|
|
if (runtime > period && runtime != RUNTIME_INF)
|
|
return -EINVAL;
|
|
|
|
mutex_lock(&rt_constraints_mutex);
|
|
read_lock(&tasklist_lock);
|
|
ret = __rt_schedulable(NULL, 0, 0);
|
|
read_unlock(&tasklist_lock);
|
|
mutex_unlock(&rt_constraints_mutex);
|
|
|
|
return ret;
|
|
}
|
|
|
|
int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk)
|
|
{
|
|
/* Don't accept realtime tasks when there is no way for them to run */
|
|
if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0)
|
|
return 0;
|
|
|
|
return 1;
|
|
}
|
|
|
|
#else /* !CONFIG_RT_GROUP_SCHED */
|
|
static int sched_rt_global_constraints(void)
|
|
{
|
|
unsigned long flags;
|
|
int i;
|
|
|
|
if (sysctl_sched_rt_period <= 0)
|
|
return -EINVAL;
|
|
|
|
/*
|
|
* There's always some RT tasks in the root group
|
|
* -- migration, kstopmachine etc..
|
|
*/
|
|
if (sysctl_sched_rt_runtime == 0)
|
|
return -EBUSY;
|
|
|
|
raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
|
|
for_each_possible_cpu(i) {
|
|
struct rt_rq *rt_rq = &cpu_rq(i)->rt;
|
|
|
|
raw_spin_lock(&rt_rq->rt_runtime_lock);
|
|
rt_rq->rt_runtime = global_rt_runtime();
|
|
raw_spin_unlock(&rt_rq->rt_runtime_lock);
|
|
}
|
|
raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
|
|
|
|
return 0;
|
|
}
|
|
#endif /* CONFIG_RT_GROUP_SCHED */
|
|
|
|
int sched_rt_handler(struct ctl_table *table, int write,
|
|
void __user *buffer, size_t *lenp,
|
|
loff_t *ppos)
|
|
{
|
|
int ret;
|
|
int old_period, old_runtime;
|
|
static DEFINE_MUTEX(mutex);
|
|
|
|
mutex_lock(&mutex);
|
|
old_period = sysctl_sched_rt_period;
|
|
old_runtime = sysctl_sched_rt_runtime;
|
|
|
|
ret = proc_dointvec(table, write, buffer, lenp, ppos);
|
|
|
|
if (!ret && write) {
|
|
ret = sched_rt_global_constraints();
|
|
if (ret) {
|
|
sysctl_sched_rt_period = old_period;
|
|
sysctl_sched_rt_runtime = old_runtime;
|
|
} else {
|
|
def_rt_bandwidth.rt_runtime = global_rt_runtime();
|
|
def_rt_bandwidth.rt_period =
|
|
ns_to_ktime(global_rt_period());
|
|
}
|
|
}
|
|
mutex_unlock(&mutex);
|
|
|
|
return ret;
|
|
}
|
|
|
|
#ifdef CONFIG_CGROUP_SCHED
|
|
|
|
/* return corresponding task_group object of a cgroup */
|
|
static inline struct task_group *cgroup_tg(struct cgroup *cgrp)
|
|
{
|
|
return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id),
|
|
struct task_group, css);
|
|
}
|
|
|
|
static struct cgroup_subsys_state *cpu_cgroup_create(struct cgroup *cgrp)
|
|
{
|
|
struct task_group *tg, *parent;
|
|
|
|
if (!cgrp->parent) {
|
|
/* This is early initialization for the top cgroup */
|
|
return &root_task_group.css;
|
|
}
|
|
|
|
parent = cgroup_tg(cgrp->parent);
|
|
tg = sched_create_group(parent);
|
|
if (IS_ERR(tg))
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
return &tg->css;
|
|
}
|
|
|
|
static void cpu_cgroup_destroy(struct cgroup *cgrp)
|
|
{
|
|
struct task_group *tg = cgroup_tg(cgrp);
|
|
|
|
sched_destroy_group(tg);
|
|
}
|
|
|
|
static int cpu_cgroup_can_attach(struct cgroup *cgrp,
|
|
struct cgroup_taskset *tset)
|
|
{
|
|
struct task_struct *task;
|
|
|
|
cgroup_taskset_for_each(task, cgrp, tset) {
|
|
#ifdef CONFIG_RT_GROUP_SCHED
|
|
if (!sched_rt_can_attach(cgroup_tg(cgrp), task))
|
|
return -EINVAL;
|
|
#else
|
|
/* We don't support RT-tasks being in separate groups */
|
|
if (task->sched_class != &fair_sched_class)
|
|
return -EINVAL;
|
|
#endif
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static void cpu_cgroup_attach(struct cgroup *cgrp,
|
|
struct cgroup_taskset *tset)
|
|
{
|
|
struct task_struct *task;
|
|
|
|
cgroup_taskset_for_each(task, cgrp, tset)
|
|
sched_move_task(task);
|
|
}
|
|
|
|
static void
|
|
cpu_cgroup_exit(struct cgroup *cgrp, struct cgroup *old_cgrp,
|
|
struct task_struct *task)
|
|
{
|
|
/*
|
|
* cgroup_exit() is called in the copy_process() failure path.
|
|
* Ignore this case since the task hasn't ran yet, this avoids
|
|
* trying to poke a half freed task state from generic code.
|
|
*/
|
|
if (!(task->flags & PF_EXITING))
|
|
return;
|
|
|
|
sched_move_task(task);
|
|
}
|
|
|
|
#ifdef CONFIG_FAIR_GROUP_SCHED
|
|
static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype,
|
|
u64 shareval)
|
|
{
|
|
return sched_group_set_shares(cgroup_tg(cgrp), scale_load(shareval));
|
|
}
|
|
|
|
static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft)
|
|
{
|
|
struct task_group *tg = cgroup_tg(cgrp);
|
|
|
|
return (u64) scale_load_down(tg->shares);
|
|
}
|
|
|
|
#ifdef CONFIG_CFS_BANDWIDTH
|
|
static DEFINE_MUTEX(cfs_constraints_mutex);
|
|
|
|
const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */
|
|
const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */
|
|
|
|
static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime);
|
|
|
|
static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota)
|
|
{
|
|
int i, ret = 0, runtime_enabled, runtime_was_enabled;
|
|
struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
|
|
|
|
if (tg == &root_task_group)
|
|
return -EINVAL;
|
|
|
|
/*
|
|
* Ensure we have at some amount of bandwidth every period. This is
|
|
* to prevent reaching a state of large arrears when throttled via
|
|
* entity_tick() resulting in prolonged exit starvation.
|
|
*/
|
|
if (quota < min_cfs_quota_period || period < min_cfs_quota_period)
|
|
return -EINVAL;
|
|
|
|
/*
|
|
* Likewise, bound things on the otherside by preventing insane quota
|
|
* periods. This also allows us to normalize in computing quota
|
|
* feasibility.
|
|
*/
|
|
if (period > max_cfs_quota_period)
|
|
return -EINVAL;
|
|
|
|
mutex_lock(&cfs_constraints_mutex);
|
|
ret = __cfs_schedulable(tg, period, quota);
|
|
if (ret)
|
|
goto out_unlock;
|
|
|
|
runtime_enabled = quota != RUNTIME_INF;
|
|
runtime_was_enabled = cfs_b->quota != RUNTIME_INF;
|
|
account_cfs_bandwidth_used(runtime_enabled, runtime_was_enabled);
|
|
raw_spin_lock_irq(&cfs_b->lock);
|
|
cfs_b->period = ns_to_ktime(period);
|
|
cfs_b->quota = quota;
|
|
|
|
__refill_cfs_bandwidth_runtime(cfs_b);
|
|
/* restart the period timer (if active) to handle new period expiry */
|
|
if (runtime_enabled && cfs_b->timer_active) {
|
|
/* force a reprogram */
|
|
cfs_b->timer_active = 0;
|
|
__start_cfs_bandwidth(cfs_b);
|
|
}
|
|
raw_spin_unlock_irq(&cfs_b->lock);
|
|
|
|
for_each_possible_cpu(i) {
|
|
struct cfs_rq *cfs_rq = tg->cfs_rq[i];
|
|
struct rq *rq = cfs_rq->rq;
|
|
|
|
raw_spin_lock_irq(&rq->lock);
|
|
cfs_rq->runtime_enabled = runtime_enabled;
|
|
cfs_rq->runtime_remaining = 0;
|
|
|
|
if (cfs_rq->throttled)
|
|
unthrottle_cfs_rq(cfs_rq);
|
|
raw_spin_unlock_irq(&rq->lock);
|
|
}
|
|
out_unlock:
|
|
mutex_unlock(&cfs_constraints_mutex);
|
|
|
|
return ret;
|
|
}
|
|
|
|
int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us)
|
|
{
|
|
u64 quota, period;
|
|
|
|
period = ktime_to_ns(tg->cfs_bandwidth.period);
|
|
if (cfs_quota_us < 0)
|
|
quota = RUNTIME_INF;
|
|
else
|
|
quota = (u64)cfs_quota_us * NSEC_PER_USEC;
|
|
|
|
return tg_set_cfs_bandwidth(tg, period, quota);
|
|
}
|
|
|
|
long tg_get_cfs_quota(struct task_group *tg)
|
|
{
|
|
u64 quota_us;
|
|
|
|
if (tg->cfs_bandwidth.quota == RUNTIME_INF)
|
|
return -1;
|
|
|
|
quota_us = tg->cfs_bandwidth.quota;
|
|
do_div(quota_us, NSEC_PER_USEC);
|
|
|
|
return quota_us;
|
|
}
|
|
|
|
int tg_set_cfs_period(struct task_group *tg, long cfs_period_us)
|
|
{
|
|
u64 quota, period;
|
|
|
|
period = (u64)cfs_period_us * NSEC_PER_USEC;
|
|
quota = tg->cfs_bandwidth.quota;
|
|
|
|
return tg_set_cfs_bandwidth(tg, period, quota);
|
|
}
|
|
|
|
long tg_get_cfs_period(struct task_group *tg)
|
|
{
|
|
u64 cfs_period_us;
|
|
|
|
cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period);
|
|
do_div(cfs_period_us, NSEC_PER_USEC);
|
|
|
|
return cfs_period_us;
|
|
}
|
|
|
|
static s64 cpu_cfs_quota_read_s64(struct cgroup *cgrp, struct cftype *cft)
|
|
{
|
|
return tg_get_cfs_quota(cgroup_tg(cgrp));
|
|
}
|
|
|
|
static int cpu_cfs_quota_write_s64(struct cgroup *cgrp, struct cftype *cftype,
|
|
s64 cfs_quota_us)
|
|
{
|
|
return tg_set_cfs_quota(cgroup_tg(cgrp), cfs_quota_us);
|
|
}
|
|
|
|
static u64 cpu_cfs_period_read_u64(struct cgroup *cgrp, struct cftype *cft)
|
|
{
|
|
return tg_get_cfs_period(cgroup_tg(cgrp));
|
|
}
|
|
|
|
static int cpu_cfs_period_write_u64(struct cgroup *cgrp, struct cftype *cftype,
|
|
u64 cfs_period_us)
|
|
{
|
|
return tg_set_cfs_period(cgroup_tg(cgrp), cfs_period_us);
|
|
}
|
|
|
|
struct cfs_schedulable_data {
|
|
struct task_group *tg;
|
|
u64 period, quota;
|
|
};
|
|
|
|
/*
|
|
* normalize group quota/period to be quota/max_period
|
|
* note: units are usecs
|
|
*/
|
|
static u64 normalize_cfs_quota(struct task_group *tg,
|
|
struct cfs_schedulable_data *d)
|
|
{
|
|
u64 quota, period;
|
|
|
|
if (tg == d->tg) {
|
|
period = d->period;
|
|
quota = d->quota;
|
|
} else {
|
|
period = tg_get_cfs_period(tg);
|
|
quota = tg_get_cfs_quota(tg);
|
|
}
|
|
|
|
/* note: these should typically be equivalent */
|
|
if (quota == RUNTIME_INF || quota == -1)
|
|
return RUNTIME_INF;
|
|
|
|
return to_ratio(period, quota);
|
|
}
|
|
|
|
static int tg_cfs_schedulable_down(struct task_group *tg, void *data)
|
|
{
|
|
struct cfs_schedulable_data *d = data;
|
|
struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
|
|
s64 quota = 0, parent_quota = -1;
|
|
|
|
if (!tg->parent) {
|
|
quota = RUNTIME_INF;
|
|
} else {
|
|
struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth;
|
|
|
|
quota = normalize_cfs_quota(tg, d);
|
|
parent_quota = parent_b->hierarchal_quota;
|
|
|
|
/*
|
|
* ensure max(child_quota) <= parent_quota, inherit when no
|
|
* limit is set
|
|
*/
|
|
if (quota == RUNTIME_INF)
|
|
quota = parent_quota;
|
|
else if (parent_quota != RUNTIME_INF && quota > parent_quota)
|
|
return -EINVAL;
|
|
}
|
|
cfs_b->hierarchal_quota = quota;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota)
|
|
{
|
|
int ret;
|
|
struct cfs_schedulable_data data = {
|
|
.tg = tg,
|
|
.period = period,
|
|
.quota = quota,
|
|
};
|
|
|
|
if (quota != RUNTIME_INF) {
|
|
do_div(data.period, NSEC_PER_USEC);
|
|
do_div(data.quota, NSEC_PER_USEC);
|
|
}
|
|
|
|
rcu_read_lock();
|
|
ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data);
|
|
rcu_read_unlock();
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int cpu_stats_show(struct cgroup *cgrp, struct cftype *cft,
|
|
struct cgroup_map_cb *cb)
|
|
{
|
|
struct task_group *tg = cgroup_tg(cgrp);
|
|
struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
|
|
|
|
cb->fill(cb, "nr_periods", cfs_b->nr_periods);
|
|
cb->fill(cb, "nr_throttled", cfs_b->nr_throttled);
|
|
cb->fill(cb, "throttled_time", cfs_b->throttled_time);
|
|
|
|
return 0;
|
|
}
|
|
#endif /* CONFIG_CFS_BANDWIDTH */
|
|
#endif /* CONFIG_FAIR_GROUP_SCHED */
|
|
|
|
#ifdef CONFIG_RT_GROUP_SCHED
|
|
static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft,
|
|
s64 val)
|
|
{
|
|
return sched_group_set_rt_runtime(cgroup_tg(cgrp), val);
|
|
}
|
|
|
|
static s64 cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft)
|
|
{
|
|
return sched_group_rt_runtime(cgroup_tg(cgrp));
|
|
}
|
|
|
|
static int cpu_rt_period_write_uint(struct cgroup *cgrp, struct cftype *cftype,
|
|
u64 rt_period_us)
|
|
{
|
|
return sched_group_set_rt_period(cgroup_tg(cgrp), rt_period_us);
|
|
}
|
|
|
|
static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft)
|
|
{
|
|
return sched_group_rt_period(cgroup_tg(cgrp));
|
|
}
|
|
#endif /* CONFIG_RT_GROUP_SCHED */
|
|
|
|
static struct cftype cpu_files[] = {
|
|
#ifdef CONFIG_FAIR_GROUP_SCHED
|
|
{
|
|
.name = "shares",
|
|
.read_u64 = cpu_shares_read_u64,
|
|
.write_u64 = cpu_shares_write_u64,
|
|
},
|
|
#endif
|
|
#ifdef CONFIG_CFS_BANDWIDTH
|
|
{
|
|
.name = "cfs_quota_us",
|
|
.read_s64 = cpu_cfs_quota_read_s64,
|
|
.write_s64 = cpu_cfs_quota_write_s64,
|
|
},
|
|
{
|
|
.name = "cfs_period_us",
|
|
.read_u64 = cpu_cfs_period_read_u64,
|
|
.write_u64 = cpu_cfs_period_write_u64,
|
|
},
|
|
{
|
|
.name = "stat",
|
|
.read_map = cpu_stats_show,
|
|
},
|
|
#endif
|
|
#ifdef CONFIG_RT_GROUP_SCHED
|
|
{
|
|
.name = "rt_runtime_us",
|
|
.read_s64 = cpu_rt_runtime_read,
|
|
.write_s64 = cpu_rt_runtime_write,
|
|
},
|
|
{
|
|
.name = "rt_period_us",
|
|
.read_u64 = cpu_rt_period_read_uint,
|
|
.write_u64 = cpu_rt_period_write_uint,
|
|
},
|
|
#endif
|
|
{ } /* terminate */
|
|
};
|
|
|
|
struct cgroup_subsys cpu_cgroup_subsys = {
|
|
.name = "cpu",
|
|
.create = cpu_cgroup_create,
|
|
.destroy = cpu_cgroup_destroy,
|
|
.can_attach = cpu_cgroup_can_attach,
|
|
.attach = cpu_cgroup_attach,
|
|
.exit = cpu_cgroup_exit,
|
|
.subsys_id = cpu_cgroup_subsys_id,
|
|
.base_cftypes = cpu_files,
|
|
.early_init = 1,
|
|
};
|
|
|
|
#endif /* CONFIG_CGROUP_SCHED */
|
|
|
|
#ifdef CONFIG_CGROUP_CPUACCT
|
|
|
|
/*
|
|
* CPU accounting code for task groups.
|
|
*
|
|
* Based on the work by Paul Menage (menage@google.com) and Balbir Singh
|
|
* (balbir@in.ibm.com).
|
|
*/
|
|
|
|
/* create a new cpu accounting group */
|
|
static struct cgroup_subsys_state *cpuacct_create(struct cgroup *cgrp)
|
|
{
|
|
struct cpuacct *ca;
|
|
|
|
if (!cgrp->parent)
|
|
return &root_cpuacct.css;
|
|
|
|
ca = kzalloc(sizeof(*ca), GFP_KERNEL);
|
|
if (!ca)
|
|
goto out;
|
|
|
|
ca->cpuusage = alloc_percpu(u64);
|
|
if (!ca->cpuusage)
|
|
goto out_free_ca;
|
|
|
|
ca->cpustat = alloc_percpu(struct kernel_cpustat);
|
|
if (!ca->cpustat)
|
|
goto out_free_cpuusage;
|
|
|
|
return &ca->css;
|
|
|
|
out_free_cpuusage:
|
|
free_percpu(ca->cpuusage);
|
|
out_free_ca:
|
|
kfree(ca);
|
|
out:
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
/* destroy an existing cpu accounting group */
|
|
static void cpuacct_destroy(struct cgroup *cgrp)
|
|
{
|
|
struct cpuacct *ca = cgroup_ca(cgrp);
|
|
|
|
free_percpu(ca->cpustat);
|
|
free_percpu(ca->cpuusage);
|
|
kfree(ca);
|
|
}
|
|
|
|
static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu)
|
|
{
|
|
u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
|
|
u64 data;
|
|
|
|
#ifndef CONFIG_64BIT
|
|
/*
|
|
* Take rq->lock to make 64-bit read safe on 32-bit platforms.
|
|
*/
|
|
raw_spin_lock_irq(&cpu_rq(cpu)->lock);
|
|
data = *cpuusage;
|
|
raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
|
|
#else
|
|
data = *cpuusage;
|
|
#endif
|
|
|
|
return data;
|
|
}
|
|
|
|
static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val)
|
|
{
|
|
u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
|
|
|
|
#ifndef CONFIG_64BIT
|
|
/*
|
|
* Take rq->lock to make 64-bit write safe on 32-bit platforms.
|
|
*/
|
|
raw_spin_lock_irq(&cpu_rq(cpu)->lock);
|
|
*cpuusage = val;
|
|
raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
|
|
#else
|
|
*cpuusage = val;
|
|
#endif
|
|
}
|
|
|
|
/* return total cpu usage (in nanoseconds) of a group */
|
|
static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft)
|
|
{
|
|
struct cpuacct *ca = cgroup_ca(cgrp);
|
|
u64 totalcpuusage = 0;
|
|
int i;
|
|
|
|
for_each_present_cpu(i)
|
|
totalcpuusage += cpuacct_cpuusage_read(ca, i);
|
|
|
|
return totalcpuusage;
|
|
}
|
|
|
|
static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype,
|
|
u64 reset)
|
|
{
|
|
struct cpuacct *ca = cgroup_ca(cgrp);
|
|
int err = 0;
|
|
int i;
|
|
|
|
if (reset) {
|
|
err = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
for_each_present_cpu(i)
|
|
cpuacct_cpuusage_write(ca, i, 0);
|
|
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
static int cpuacct_percpu_seq_read(struct cgroup *cgroup, struct cftype *cft,
|
|
struct seq_file *m)
|
|
{
|
|
struct cpuacct *ca = cgroup_ca(cgroup);
|
|
u64 percpu;
|
|
int i;
|
|
|
|
for_each_present_cpu(i) {
|
|
percpu = cpuacct_cpuusage_read(ca, i);
|
|
seq_printf(m, "%llu ", (unsigned long long) percpu);
|
|
}
|
|
seq_printf(m, "\n");
|
|
return 0;
|
|
}
|
|
|
|
static const char *cpuacct_stat_desc[] = {
|
|
[CPUACCT_STAT_USER] = "user",
|
|
[CPUACCT_STAT_SYSTEM] = "system",
|
|
};
|
|
|
|
static int cpuacct_stats_show(struct cgroup *cgrp, struct cftype *cft,
|
|
struct cgroup_map_cb *cb)
|
|
{
|
|
struct cpuacct *ca = cgroup_ca(cgrp);
|
|
int cpu;
|
|
s64 val = 0;
|
|
|
|
for_each_online_cpu(cpu) {
|
|
struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu);
|
|
val += kcpustat->cpustat[CPUTIME_USER];
|
|
val += kcpustat->cpustat[CPUTIME_NICE];
|
|
}
|
|
val = cputime64_to_clock_t(val);
|
|
cb->fill(cb, cpuacct_stat_desc[CPUACCT_STAT_USER], val);
|
|
|
|
val = 0;
|
|
for_each_online_cpu(cpu) {
|
|
struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu);
|
|
val += kcpustat->cpustat[CPUTIME_SYSTEM];
|
|
val += kcpustat->cpustat[CPUTIME_IRQ];
|
|
val += kcpustat->cpustat[CPUTIME_SOFTIRQ];
|
|
}
|
|
|
|
val = cputime64_to_clock_t(val);
|
|
cb->fill(cb, cpuacct_stat_desc[CPUACCT_STAT_SYSTEM], val);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct cftype files[] = {
|
|
{
|
|
.name = "usage",
|
|
.read_u64 = cpuusage_read,
|
|
.write_u64 = cpuusage_write,
|
|
},
|
|
{
|
|
.name = "usage_percpu",
|
|
.read_seq_string = cpuacct_percpu_seq_read,
|
|
},
|
|
{
|
|
.name = "stat",
|
|
.read_map = cpuacct_stats_show,
|
|
},
|
|
{ } /* terminate */
|
|
};
|
|
|
|
/*
|
|
* charge this task's execution time to its accounting group.
|
|
*
|
|
* called with rq->lock held.
|
|
*/
|
|
void cpuacct_charge(struct task_struct *tsk, u64 cputime)
|
|
{
|
|
struct cpuacct *ca;
|
|
int cpu;
|
|
|
|
if (unlikely(!cpuacct_subsys.active))
|
|
return;
|
|
|
|
cpu = task_cpu(tsk);
|
|
|
|
rcu_read_lock();
|
|
|
|
ca = task_ca(tsk);
|
|
|
|
for (; ca; ca = parent_ca(ca)) {
|
|
u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
|
|
*cpuusage += cputime;
|
|
}
|
|
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
struct cgroup_subsys cpuacct_subsys = {
|
|
.name = "cpuacct",
|
|
.create = cpuacct_create,
|
|
.destroy = cpuacct_destroy,
|
|
.subsys_id = cpuacct_subsys_id,
|
|
.base_cftypes = files,
|
|
};
|
|
#endif /* CONFIG_CGROUP_CPUACCT */
|