Christian Borntraeger 3401a61e16 stop_machine: make stop_machine_run more virtualization friendly ... On kvm I have seen some rare hangs in stop_machine when I used more guest cpus than hosts cpus. e.g. 32 guest cpus on 1 host cpu triggered the hang quite often. I could also reproduce the problem on a 4 way z/VM host with a 64 way guest. It turned out that the guest was consuming all available cpus mostly for spinning on scheduler locks like rq->lock. This is expected as the threads are calling yield all the time. The problem is now, that the host scheduling decisings together with the guest scheduling decisions and spinlocks not being fair managed to create an interesting scenario similar to a live lock. (Sometimes the hang resolved itself after some minutes) Changing stop_machine to yield the cpu to the hypervisor when yielding inside the guest fixed the problem for me. While I am not completely happy with this patch, I think it causes no harm and it really improves the situation for me. I used cpu_relax for yielding to the hypervisor, does that work on all architectures? p.s.: If you want to reproduce the problem, cpu hotplug and kprobes use stop_machine_run and both triggered the problem after some retries. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> CC: Ingo Molnar <mingo@elte.hu> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>		2008-05-23 13:09:34 +10:00
..
irq	genirq: reenable a nobody cared disabled irq when a new driver arrives	2008-05-02 13:40:34 +02:00
power	Merge branches 'release', 'acpica', 'bugzilla-10224', 'bugzilla-9772', 'bugzilla-9916', 'ec', 'eeepc', 'idle', 'misc', 'pm-legacy', 'sysfs-links-2.6.26', 'thermal', 'thinkpad' and 'video' into release	2008-04-30 13:58:00 -04:00
time	clocksource: allow read access to available/current_clocksource	2008-05-03 18:11:48 +02:00
.gitignore	Update kernel/.gitignore with new auto-generated files	2008-02-09 23:27:01 -08:00
Kconfig.hz	sched: high-res preemption tick	2008-01-25 21:08:29 +01:00
Kconfig.preempt	rcu: move PREEMPT_RCU config option back under PREEMPT	2008-03-10 18:01:20 -07:00
Makefile	sched: add optional support for CONFIG_HAVE_UNSTABLE_SCHED_CLOCK	2008-05-05 23:56:18 +02:00
acct.c	bsd_acct: using task_struct->tgid is not right in pid-namespaces	2008-03-24 19:22:20 -07:00
audit.c	[patch 1/1] audit_send_reply(): fix error-path memory leak	2008-05-17 03:30:22 -04:00
audit.h	[PATCH 1/2] audit: move extern declarations to audit.h	2008-04-28 06:28:04 -04:00
audit_tree.c	[PATCH] list_for_each_rcu must die: audit	2008-05-17 03:30:23 -04:00
auditfilter.c	Merge branch 'audit.b50' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current	2008-04-29 11:41:22 -07:00
auditsc.c	[PATCH] new predicate - AUDIT_FILETYPE	2008-04-28 06:28:37 -04:00
backtracetest.c	x86: add a simple backtrace test module	2008-01-30 13:33:08 +01:00
bounds.c	Add kbuild.h that contains common definitions for kbuild users	2008-04-29 08:06:29 -07:00
capability.c	Add 64-bit capability support to the kernel	2008-02-05 09:44:20 -08:00
cgroup.c	mm: bdi: add separate writeback accounting capability	2008-04-30 08:29:50 -07:00
cgroup_debug.c	CGroup API files: move "releasable" to cgroup_debug subsystem	2008-04-29 08:06:09 -07:00
compat.c	ntp: support for TAI	2008-05-01 08:03:59 -07:00
configs.c	kernel: use non-racy method for proc entries creation	2008-04-29 08:06:22 -07:00
cpu.c	kernel: replace remaining __FUNCTION__ occurrences	2008-04-30 08:29:54 -07:00
cpuset.c	Fix cpuset sched_relax_domain_level control file	2008-05-08 10:46:56 -07:00
delayacct.c	…
dma.c	kernel: use non-racy method for proc entries creation	2008-04-29 08:06:22 -07:00
exec_domain.c	…
exit.c	[PATCH] split linux/file.h	2008-05-01 13:08:16 -04:00
extable.c	module: Don't report discarded init pages as kernel text.	2008-01-29 17:13:18 +11:00
fork.c	[PATCH] dup_fd() fixes, part 1	2008-05-16 17:22:26 -04:00
futex.c	Removal of FUTEX_FD	2008-05-05 08:18:45 -07:00
futex_compat.c	futex_compat __user annotation	2008-03-30 14:18:41 -07:00
hrtimer.c	hrtimer: remove duplicate helper function	2008-05-03 18:11:48 +02:00
itimer.c	ITIMER_REAL: convert to use struct pid	2008-02-08 09:22:29 -08:00
kallsyms.c	kernel: use non-racy method for proc entries creation	2008-04-29 08:06:22 -07:00
kexec.c	kexec: make extended crashkernel= syntax less confusing	2008-05-01 08:04:00 -07:00
kfifo.c	…
kgdb.c	lib: create common ascii hex array	2008-05-14 19:11:14 -07:00
kmod.c	[PATCH] split linux/file.h	2008-05-01 13:08:16 -04:00
kprobes.c	kprobes: add (un)register_jprobes for batch registration	2008-04-28 08:58:32 -07:00
ksysfs.c	Kobject: convert remaining kobject_unregister() to kobject_put()	2008-01-24 20:40:40 -08:00
kthread.c	Deprecate find_task_by_pid()	2008-04-30 08:29:48 -07:00
latencytop.c	kernel: use non-racy method for proc entries creation	2008-04-29 08:06:22 -07:00
lockdep.c	Subject: lockdep: include all lock classes in all_lock_classes	2008-02-25 23:03:02 +01:00
lockdep_internals.h	…
lockdep_proc.c	kernel: use non-racy method for proc entries creation	2008-04-29 08:06:22 -07:00
marker.c	make marker_debug static	2008-04-30 08:29:49 -07:00
module.c	modules: proper cleanup of kobject without CONFIG_SYSFS	2008-05-23 13:09:33 +10:00
mutex-debug.c	kernel: remove fastcall in kernel/*	2008-02-08 09:22:31 -08:00
mutex-debug.h	…
mutex.c	kernel: remove fastcall in kernel/*	2008-02-08 09:22:31 -08:00
mutex.h	…
notifier.c	ipc: re-enable msgmni automatic recomputing msgmni if set to negative	2008-04-29 08:06:13 -07:00
ns_cgroup.c	cgroups: kernel/ns_cgroup.c should #include <linux/nsproxy.h>	2008-04-29 08:06:07 -07:00
nsproxy.c	ipc: sysvsem: refuse clone(CLONE_SYSVSEM|CLONE_NEWIPC)	2008-04-29 08:06:14 -07:00
panic.c	Taint kernel after WARN_ON(condition)	2008-04-29 08:05:59 -07:00
params.c	Add new string functions strict_strto* and convert kernel params to use them	2008-02-08 09:22:41 -08:00
pid.c	pids: introduce change_pid() helper	2008-04-30 08:29:48 -07:00
pid_namespace.c	pidns: make pid->level and pid_ns->level unsigned	2008-04-30 08:29:49 -07:00
pm_qos_params.c	pm qos infrastructure and interface	2008-02-05 09:44:22 -08:00
posix-cpu-timers.c	remove div_long_long_rem	2008-05-01 08:03:58 -07:00
posix-timers.c	signals: join send_sigqueue() with send_group_sigqueue()	2008-04-30 08:29:36 -07:00
printk.c	printk: don't read beyond string arguments' terminating zero	2008-04-30 08:29:52 -07:00
profile.c	kernel: use non-racy method for proc entries creation	2008-04-29 08:06:22 -07:00
ptrace.c	make generic sys_ptrace unconditional	2008-05-01 10:21:54 -07:00
rcuclassic.c	Preempt-RCU: implementation	2008-01-25 21:08:24 +01:00
rcupdate.c	rcupdate: fix comment	2008-02-13 16:21:18 -08:00
rcupreempt.c	generic: reduce stack pressure in sched_affinity	2008-04-19 19:44:59 +02:00
rcupreempt_trace.c	Preempt-RCU: implementation	2008-01-25 21:08:24 +01:00
rcutorture.c	kernel: explicitly include required header files under kernel/	2008-04-29 08:06:04 -07:00
relay.c	Revert "relay: fix splice problem"	2008-05-08 14:06:19 +02:00
res_counter.c	memcgroup: add the max_usage member on the res_counter	2008-04-29 08:06:10 -07:00
resource.c	kernel: use non-racy method for proc entries creation	2008-04-29 08:06:22 -07:00
rtmutex-debug.c	Don't operate with pid_t in rtmutex tester	2008-02-08 09:22:41 -08:00
rtmutex-debug.h	…
rtmutex-tester.c	Driver core: change sysdev classes to use dynamic kobject names	2008-01-24 20:40:40 -08:00
rtmutex.c	hrtimer: more hrtimer_init_sleeper() fallout.	2008-02-13 15:45:36 +01:00
rtmutex.h	…
rtmutex_common.h	Don't operate with pid_t in rtmutex tester	2008-02-08 09:22:41 -08:00
rwsem.c	sched: mark rwsem functions as __sched for wchan/profiling	2007-12-18 15:21:13 +01:00
sched.c	cgroups: fix compile warning	2008-05-14 19:11:14 -07:00
sched_clock.c	sched: add optional support for CONFIG_HAVE_UNSTABLE_SCHED_CLOCK	2008-05-05 23:56:18 +02:00
sched_debug.c	sched: add optional support for CONFIG_HAVE_UNSTABLE_SCHED_CLOCK	2008-05-05 23:56:18 +02:00
sched_fair.c	sched: fix weight calculations	2008-05-08 17:00:42 +02:00
sched_features.h	sched: /debug/sched_features	2008-04-19 19:45:00 +02:00
sched_idletask.c	sched: make rt_sched_class, idle_sched_class static	2008-05-05 23:56:17 +02:00
sched_rt.c	sched: fix RT task-wakeup logic	2008-05-05 23:56:18 +02:00
sched_stats.h	cpumask: use new cpus_scnprintf function	2008-04-19 19:44:59 +02:00
seccomp.c	…
semaphore.c	Revert "semaphore: fix"	2008-05-10 20:43:22 -07:00
signal.c	signals: add set_restore_sigmask	2008-04-30 08:29:37 -07:00
softirq.c	Fix cpu hotplug problem in softirq code	2008-05-01 08:03:58 -07:00
softlockup.c	softlockup: fix task state setting	2008-02-29 18:46:53 +01:00
spinlock.c	spinlock: lockbreak cleanup	2008-01-30 13:31:20 +01:00
srcu.c	make srcu_readers_active() static	2008-02-06 10:41:02 -08:00
stacktrace.c	…
stop_machine.c	stop_machine: make stop_machine_run more virtualization friendly	2008-05-23 13:09:34 +10:00
sys.c	pids: sys_getpgid: fix unsafe *pid usage, s/tasklist/rcu/	2008-04-30 08:29:49 -07:00
sys_ni.c	timerfd: new timerfd API	2008-02-05 09:44:07 -08:00
sysctl.c	[PATCH] avoid multiplication overflows and signedness issues for max_fds	2008-05-16 17:22:52 -04:00
sysctl_check.c	constify tables in kernel/sysctl_check.c	2008-02-08 09:22:31 -08:00
taskstats.c	Use find_task_by_vpid in taskstats	2008-04-30 08:29:48 -07:00
test_kprobes.c	kprobes: kretprobe user entry-handler	2008-02-06 10:41:11 -08:00
time.c	Make constants in kernel/timeconst.h fixed 64 bits	2008-05-02 16:18:42 -07:00
timeconst.pl	Make constants in kernel/timeconst.h fixed 64 bits	2008-05-02 16:18:42 -07:00
timer.c	debugobjects: add timer specific object debugging code	2008-04-30 08:29:53 -07:00
tsacct.c	…
uid16.c	asmlinkage_protect replaces prevent_tail_call	2008-04-10 17:28:26 -07:00
user.c	alloc_uid: cleanup	2008-04-30 08:29:53 -07:00
user_namespace.c	eCryptfs: make key module subsystem respect namespaces	2008-04-29 08:06:07 -07:00
utsname.c	kernel: explicitly include required header files under kernel/	2008-04-29 08:06:04 -07:00
utsname_sysctl.c	…
wait.c	kernel: remove fastcall in kernel/*	2008-02-08 09:22:31 -08:00
workqueue.c	workqueue: remove redundant function invocation	2008-05-01 08:04:02 -07:00