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Commit ef8745c1 authored by KAMEZAWA Hiroyuki's avatar KAMEZAWA Hiroyuki Committed by Linus Torvalds
Browse files

memcg: reduce check for softlimit excess 



In charge/uncharge/reclaim path, usage_in_excess is calculated repeatedly
and it takes res_counter's spin_lock every time.

This patch removes unnecessary calls for res_count_soft_limit_excess.

Reviewed-by: default avatarDaisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4e649152

mm/memcontrol.c

+15 −16
Original line number Diff line number Diff line
@@ -313,7 +313,8 @@ soft_limit_tree_from_page(struct page *page) 
static void

__mem_cgroup_insert_exceeded(struct mem_cgroup *mem,

				struct mem_cgroup_per_zone *mz,

				struct mem_cgroup_tree_per_zone *mctz)

				struct mem_cgroup_tree_per_zone *mctz,

				unsigned long long new_usage_in_excess)

{

	struct rb_node **p = &mctz->rb_root.rb_node;

	struct rb_node *parent = NULL;
@@ -322,7 +323,9 @@ __mem_cgroup_insert_exceeded(struct mem_cgroup *mem, 
	if (mz->on_tree)

		return;



	mz->usage_in_excess = res_counter_soft_limit_excess(&mem->res);

	mz->usage_in_excess = new_usage_in_excess;

	if (!mz->usage_in_excess)

		return;

	while (*p) {

		parent = *p;

		mz_node = rb_entry(parent, struct mem_cgroup_per_zone,
@@ -382,7 +385,7 @@ static bool mem_cgroup_soft_limit_check(struct mem_cgroup *mem) 


static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page)

{

	unsigned long long new_usage_in_excess;

	unsigned long long excess;

	struct mem_cgroup_per_zone *mz;

	struct mem_cgroup_tree_per_zone *mctz;

	int nid = page_to_nid(page);
@@ -395,25 +398,21 @@ static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page) 
	 */

	for (; mem; mem = parent_mem_cgroup(mem)) {

		mz = mem_cgroup_zoneinfo(mem, nid, zid);

		new_usage_in_excess =

			res_counter_soft_limit_excess(&mem->res);

		excess = res_counter_soft_limit_excess(&mem->res);

		/*

		 * We have to update the tree if mz is on RB-tree or

		 * mem is over its softlimit.

		 */

		if (new_usage_in_excess || mz->on_tree) {

		if (excess || mz->on_tree) {

			spin_lock(&mctz->lock);

			/* if on-tree, remove it */

			if (mz->on_tree)

				__mem_cgroup_remove_exceeded(mem, mz, mctz);

			/*

			 * if over soft limit, insert again. mz->usage_in_excess

			 * will be updated properly.

			 * Insert again. mz->usage_in_excess will be updated.

			 * If excess is 0, no tree ops.

			 */

			if (new_usage_in_excess)

				__mem_cgroup_insert_exceeded(mem, mz, mctz);

			else

				mz->usage_in_excess = 0;

			__mem_cgroup_insert_exceeded(mem, mz, mctz, excess);

			spin_unlock(&mctz->lock);

		}

	}
@@ -2221,6 +2220,7 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order, 
	unsigned long reclaimed;

	int loop = 0;

	struct mem_cgroup_tree_per_zone *mctz;

	unsigned long long excess;



	if (order > 0)

		return 0;
@@ -2272,9 +2272,8 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order, 
					break;

			} while (1);

		}

		mz->usage_in_excess =

			res_counter_soft_limit_excess(&mz->mem->res);

		__mem_cgroup_remove_exceeded(mz->mem, mz, mctz);

		excess = res_counter_soft_limit_excess(&mz->mem->res);

		/*

		 * One school of thought says that we should not add

		 * back the node to the tree if reclaim returns 0.
@@ -2283,8 +2282,8 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order, 
		 * memory to reclaim from. Consider this as a longer

		 * term TODO.

		 */

		if (mz->usage_in_excess)

			__mem_cgroup_insert_exceeded(mz->mem, mz, mctz);

		/* If excess == 0, no tree ops */

		__mem_cgroup_insert_exceeded(mz->mem, mz, mctz, excess);

		spin_unlock(&mctz->lock);

		css_put(&mz->mem->css);

		loop++;