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authorVladimir Davydov <vdavydov@virtuozzo.com>2015-12-11 13:40:24 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-12-12 10:15:34 -0800
commit9516a18a9a253a94292e74f11f92083126c5a237 (patch)
tree4c8cf1212ce7cea038deaf01a82e7b09efc67ebd
parenta88c769548047b21f76fd71e04b6a3300ff17160 (diff)
downloadlinux-linaro-stable-9516a18a9a253a94292e74f11f92083126c5a237.tar.gz
memcg: fix memory.high target
When the memory.high threshold is exceeded, try_charge() schedules a task_work to reclaim the excess. The reclaim target is set to the number of pages requested by try_charge(). This is wrong, because try_charge() usually charges more pages than requested (batch > nr_pages) in order to refill per cpu stocks. As a result, a process in a cgroup can easily exceed memory.high significantly when doing a lot of charges w/o returning to userspace (e.g. reading a file in big chunks). Fix this issue by assuring that when exceeding memory.high a process reclaims as many pages as were actually charged (i.e. batch). Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/memcontrol.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index c92a65b2b4ab..32259e37a66b 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2128,7 +2128,7 @@ done_restock:
*/
do {
if (page_counter_read(&memcg->memory) > memcg->high) {
- current->memcg_nr_pages_over_high += nr_pages;
+ current->memcg_nr_pages_over_high += batch;
set_notify_resume(current);
break;
}