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authorMichal Hocko <mhocko@suse.cz>2011-07-26 23:08:27 (GMT)
committerLinus Torvalds <torvalds@linux-foundation.org>2011-07-26 23:49:42 (GMT)
commitd1a05b6973c7cb33144fa965d73facc708ffc37d (patch)
tree463a8bfedd56b4972f273c816fa62a55d7bc4754
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>
-rw-r--r--mm/memcontrol.c13
1 files changed, 7 insertions, 6 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 04e505b..2f5534e 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);

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