memcg: clean up memory thresholds
Introduce struct mem_cgroup_thresholds. It helps to reduce number of checks of thresholds type (memory or mem+swap). [akpm@linux-foundation.org: repair comment] Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Cc: Phil Carmody <ext-phil.2.carmody@nokia.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Kirill A. Shutemov
Linus Torvalds
Родитель
907860ed38
Коммит
2c488db27b
151
mm/memcontrol.c
151
mm/memcontrol.c
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@ -158,6 +158,18 @@ struct mem_cgroup_threshold_ary {
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/* Array of thresholds */
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struct mem_cgroup_threshold entries[0];
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};
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struct mem_cgroup_thresholds {
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/* Primary thresholds array */
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struct mem_cgroup_threshold_ary *primary;
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/*
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* Spare threshold array.
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* This is needed to make mem_cgroup_unregister_event() "never fail".
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* It must be able to store at least primary->size - 1 entries.
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*/
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struct mem_cgroup_threshold_ary *spare;
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};
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/* for OOM */
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struct mem_cgroup_eventfd_list {
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struct list_head list;
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@ -224,20 +236,10 @@ struct mem_cgroup {
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struct mutex thresholds_lock;
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/* thresholds for memory usage. RCU-protected */
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struct mem_cgroup_threshold_ary *thresholds;
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/*
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* Preallocated buffer to be used in mem_cgroup_unregister_event()
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* to make it "never fail".
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* It must be able to store at least thresholds->size - 1 entries.
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*/
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struct mem_cgroup_threshold_ary *__thresholds;
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struct mem_cgroup_thresholds thresholds;
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/* thresholds for mem+swap usage. RCU-protected */
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struct mem_cgroup_threshold_ary *memsw_thresholds;
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/* the same as __thresholds, but for memsw_thresholds */
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struct mem_cgroup_threshold_ary *__memsw_thresholds;
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struct mem_cgroup_thresholds memsw_thresholds;
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/* For oom notifier event fd */
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struct list_head oom_notify;
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@ -3467,9 +3469,9 @@ static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
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rcu_read_lock();
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if (!swap)
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t = rcu_dereference(memcg->thresholds);
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t = rcu_dereference(memcg->thresholds.primary);
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else
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t = rcu_dereference(memcg->memsw_thresholds);
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t = rcu_dereference(memcg->memsw_thresholds.primary);
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if (!t)
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goto unlock;
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@ -3543,91 +3545,78 @@ static int mem_cgroup_usage_register_event(struct cgroup *cgrp,
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struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
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{
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struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
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struct mem_cgroup_threshold_ary *thresholds, *thresholds_new;
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struct mem_cgroup_thresholds *thresholds;
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struct mem_cgroup_threshold_ary *new;
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int type = MEMFILE_TYPE(cft->private);
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u64 threshold, usage;
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int size;
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int i, ret;
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int i, size, ret;
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ret = res_counter_memparse_write_strategy(args, &threshold);
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if (ret)
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return ret;
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mutex_lock(&memcg->thresholds_lock);
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if (type == _MEM)
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thresholds = memcg->thresholds;
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thresholds = &memcg->thresholds;
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else if (type == _MEMSWAP)
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thresholds = memcg->memsw_thresholds;
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thresholds = &memcg->memsw_thresholds;
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else
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BUG();
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usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
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/* Check if a threshold crossed before adding a new one */
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if (thresholds)
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if (thresholds->primary)
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__mem_cgroup_threshold(memcg, type == _MEMSWAP);
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if (thresholds)
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size = thresholds->size + 1;
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else
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size = 1;
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size = thresholds->primary ? thresholds->primary->size + 1 : 1;
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/* Allocate memory for new array of thresholds */
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thresholds_new = kmalloc(sizeof(*thresholds_new) +
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size * sizeof(struct mem_cgroup_threshold),
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new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
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GFP_KERNEL);
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if (!thresholds_new) {
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if (!new) {
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ret = -ENOMEM;
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goto unlock;
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}
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thresholds_new->size = size;
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new->size = size;
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/* Copy thresholds (if any) to new array */
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if (thresholds)
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memcpy(thresholds_new->entries, thresholds->entries,
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thresholds->size *
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if (thresholds->primary) {
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memcpy(new->entries, thresholds->primary->entries, (size - 1) *
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sizeof(struct mem_cgroup_threshold));
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}
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/* Add new threshold */
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thresholds_new->entries[size - 1].eventfd = eventfd;
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thresholds_new->entries[size - 1].threshold = threshold;
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new->entries[size - 1].eventfd = eventfd;
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new->entries[size - 1].threshold = threshold;
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/* Sort thresholds. Registering of new threshold isn't time-critical */
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sort(thresholds_new->entries, size,
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sizeof(struct mem_cgroup_threshold),
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sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
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compare_thresholds, NULL);
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/* Find current threshold */
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thresholds_new->current_threshold = -1;
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new->current_threshold = -1;
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for (i = 0; i < size; i++) {
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if (thresholds_new->entries[i].threshold < usage) {
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if (new->entries[i].threshold < usage) {
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/*
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* thresholds_new->current_threshold will not be used
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* until rcu_assign_pointer(), so it's safe to increment
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* new->current_threshold will not be used until
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* rcu_assign_pointer(), so it's safe to increment
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* it here.
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*/
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++thresholds_new->current_threshold;
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++new->current_threshold;
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}
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}
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if (type == _MEM)
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rcu_assign_pointer(memcg->thresholds, thresholds_new);
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else
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rcu_assign_pointer(memcg->memsw_thresholds, thresholds_new);
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/* Free old spare buffer and save old primary buffer as spare */
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kfree(thresholds->spare);
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thresholds->spare = thresholds->primary;
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rcu_assign_pointer(thresholds->primary, new);
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/* To be sure that nobody uses thresholds */
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synchronize_rcu();
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/*
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* Free old preallocated buffer and use thresholds as new
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* preallocated buffer.
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*/
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if (type == _MEM) {
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kfree(memcg->__thresholds);
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memcg->__thresholds = thresholds;
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} else {
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kfree(memcg->__memsw_thresholds);
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memcg->__memsw_thresholds = thresholds;
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}
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unlock:
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mutex_unlock(&memcg->thresholds_lock);
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@ -3638,17 +3627,17 @@ static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp,
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struct cftype *cft, struct eventfd_ctx *eventfd)
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{
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struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
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struct mem_cgroup_threshold_ary *thresholds, *thresholds_new;
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struct mem_cgroup_thresholds *thresholds;
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struct mem_cgroup_threshold_ary *new;
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int type = MEMFILE_TYPE(cft->private);
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u64 usage;
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int size = 0;
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int i, j;
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int i, j, size;
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mutex_lock(&memcg->thresholds_lock);
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if (type == _MEM)
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thresholds = memcg->thresholds;
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thresholds = &memcg->thresholds;
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else if (type == _MEMSWAP)
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thresholds = memcg->memsw_thresholds;
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thresholds = &memcg->memsw_thresholds;
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else
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BUG();
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@ -3664,53 +3653,45 @@ static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp,
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__mem_cgroup_threshold(memcg, type == _MEMSWAP);
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/* Calculate new number of threshold */
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for (i = 0; i < thresholds->size; i++) {
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if (thresholds->entries[i].eventfd != eventfd)
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size = 0;
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for (i = 0; i < thresholds->primary->size; i++) {
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if (thresholds->primary->entries[i].eventfd != eventfd)
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size++;
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}
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/* Use preallocated buffer for new array of thresholds */
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if (type == _MEM)
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thresholds_new = memcg->__thresholds;
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else
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thresholds_new = memcg->__memsw_thresholds;
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new = thresholds->spare;
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/* Set thresholds array to NULL if we don't have thresholds */
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if (!size) {
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kfree(thresholds_new);
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thresholds_new = NULL;
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kfree(new);
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new = NULL;
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goto swap_buffers;
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}
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thresholds_new->size = size;
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new->size = size;
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/* Copy thresholds and find current threshold */
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thresholds_new->current_threshold = -1;
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for (i = 0, j = 0; i < thresholds->size; i++) {
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if (thresholds->entries[i].eventfd == eventfd)
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new->current_threshold = -1;
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for (i = 0, j = 0; i < thresholds->primary->size; i++) {
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if (thresholds->primary->entries[i].eventfd == eventfd)
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continue;
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thresholds_new->entries[j] = thresholds->entries[i];
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if (thresholds_new->entries[j].threshold < usage) {
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new->entries[j] = thresholds->primary->entries[i];
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if (new->entries[j].threshold < usage) {
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/*
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* thresholds_new->current_threshold will not be used
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* new->current_threshold will not be used
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* until rcu_assign_pointer(), so it's safe to increment
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* it here.
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*/
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++thresholds_new->current_threshold;
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++new->current_threshold;
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}
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j++;
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}
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swap_buffers:
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/* Swap thresholds array and preallocated buffer */
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if (type == _MEM) {
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memcg->__thresholds = thresholds;
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rcu_assign_pointer(memcg->thresholds, thresholds_new);
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} else {
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memcg->__memsw_thresholds = thresholds;
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rcu_assign_pointer(memcg->memsw_thresholds, thresholds_new);
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}
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/* Swap primary and spare array */
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thresholds->spare = thresholds->primary;
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rcu_assign_pointer(thresholds->primary, new);
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/* To be sure that nobody uses thresholds */
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synchronize_rcu();
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