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authorMichal Hocko <mhocko@suse.cz>2011-07-26 16:08:27 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-07-26 16:49:42 -0700
commitd1a05b6973c7cb33144fa965d73facc708ffc37d (patch)
tree463a8bfedd56b4972f273c816fa62a55d7bc4754 /mm/memcontrol.c
parent82f9d486e59f588c7d100865c36510644abda356 (diff)
memcg: do not try to drain per-cpu caches without pages
drain_all_stock_async tries to optimize a work to be done on the work queue by excluding any work for the current CPU because it assumes that the context we are called from already tried to charge from that cache and it's failed so it must be empty already. While the assumption is correct we can optimize it even more by checking the current number of pages in the cache. This will also reduce a work on other CPUs with an empty stock. For the current CPU we can simply call drain_local_stock rather than deferring it to the work queue. [kamezawa.hiroyu@jp.fujitsu.com: use drain_local_stock for current CPU optimization] Signed-off-by: Michal Hocko <mhocko@suse.cz> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memcontrol.c')
-rw-r--r--mm/memcontrol.c13
1 files changed, 7 insertions, 6 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 04e505bfd7dd..2f5534e1968c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2180,11 +2180,8 @@ static void drain_all_stock_async(struct mem_cgroup *root_mem)
struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
struct mem_cgroup *mem;
- if (cpu == curcpu)
- continue;
-
mem = stock->cached;
- if (!mem)
+ if (!mem || !stock->nr_pages)
continue;
if (mem != root_mem) {
if (!root_mem->use_hierarchy)
@@ -2193,8 +2190,12 @@ static void drain_all_stock_async(struct mem_cgroup *root_mem)
if (!css_is_ancestor(&mem->css, &root_mem->css))
continue;
}
- if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags))
- schedule_work_on(cpu, &stock->work);
+ if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
+ if (cpu == curcpu)
+ drain_local_stock(&stock->work);
+ else
+ schedule_work_on(cpu, &stock->work);
+ }
}
put_online_cpus();
mutex_unlock(&percpu_charge_mutex);