From ef8745c1e7fc5413d760b3b958f3fd3a0beaad72 Mon Sep 17 00:00:00 2001 From: KAMEZAWA Hiroyuki Date: Thu, 1 Oct 2009 15:44:12 -0700 Subject: [PATCH] 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: Daisuke Nishimura Signed-off-by: KAMEZAWA Hiroyuki Cc: Paul Menage Cc: Li Zefan Cc: Balbir Singh Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memcontrol.c | 31 +++++++++++++++---------------- 1 file changed, 15 insertions(+), 16 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 1ae8c43..f99f599 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -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++; -- 1.8.2.3