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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 <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: KAMEZAWA 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
KAMEZAWA Hiroyuki 2009-10-01 15:44:12 -07:00 committed by Linus Torvalds
parent 4e649152cb
commit ef8745c1e7
1 changed files with 15 additions and 16 deletions
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31
mm/memcontrol.c
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@ -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++;