memcg: protect prev_priority (2733c06a) · Commits · 戴 / test

Currently, mem_cgroup doesn't have own lock and almost its member doesn't need. (e.g. mem_cgroup->info is protected by zone lock, mem_cgroup->stat is per cpu variable) However, there is one explict exception. mem_cgroup->prev_priorit need lock, but doesn't protect. Luckly, this is NOT bug because prev_priority isn't used for current reclaim code. However, we plan to use prev_priority future again. Therefore, fixing is better. In addition, we plan to reuse this lock for another member. Then "reclaim_param_lock" name is better than "prev_priority_lock". Acked-by:

KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by:

KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Hugh Dickins <hugh@veritas.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/memcontrol.c

+17 −1

Original line number	Diff line number	Diff line
		@@ -144,6 +144,11 @@ struct mem_cgroup {
		*/
		struct mem_cgroup_lru_info info;

		/*
		protect against reclaim related member.
		*/
		spinlock_t reclaim_param_lock;

		int prev_priority; /* for recording reclaim priority */

		/*
		@@ -400,18 +405,28 @@ int mem_cgroup_calc_mapped_ratio(struct mem_cgroup *mem)
		*/
		int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem)
		{
		return mem->prev_priority;
		int prev_priority;

		spin_lock(&mem->reclaim_param_lock);
		prev_priority = mem->prev_priority;
		spin_unlock(&mem->reclaim_param_lock);

		return prev_priority;
		}

		void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem, int priority)
		{
		spin_lock(&mem->reclaim_param_lock);
		if (priority < mem->prev_priority)
		mem->prev_priority = priority;
		spin_unlock(&mem->reclaim_param_lock);
		}

		void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem, int priority)
		{
		spin_lock(&mem->reclaim_param_lock);
		mem->prev_priority = priority;
		spin_unlock(&mem->reclaim_param_lock);
		}

		int mem_cgroup_inactive_anon_is_low(struct mem_cgroup memcg, struct zone zone)
		@@ -2076,6 +2091,7 @@ mem_cgroup_create(struct cgroup_subsys ss, struct cgroup cont)
		}
		mem_cgroup_set_inactive_ratio(mem);
		mem->last_scanned_child = NULL;
		spin_lock_init(&mem->reclaim_param_lock);

		return &mem->css;
		free_out:

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