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authorJohannes Weiner <hannes@cmpxchg.org>2016-03-17 14:20:25 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-03-17 15:09:34 -0700
commit588083bb37a3cea8533c392370a554417c8f29cb (patch)
treec2ae9e34d17c670f40a1748a086f0709449900a1 /mm
parentd9b2ddf8078f743729a054362ad96be076f224af (diff)
downloadlwn-588083bb37a3cea8533c392370a554417c8f29cb.tar.gz
lwn-588083bb37a3cea8533c392370a554417c8f29cb.zip
mm: memcontrol: reclaim when shrinking memory.high below usage
When setting memory.high below usage, nothing happens until the next charge comes along, and then it will only reclaim its own charge and not the now potentially huge excess of the new memory.high. This can cause groups to stay in excess of their memory.high indefinitely. To fix that, when shrinking memory.high, kick off a reclaim cycle that goes after the delta. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/memcontrol.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 8615b066b642..f7c9b4cbdf01 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4992,6 +4992,7 @@ static ssize_t memory_high_write(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
+ unsigned long nr_pages;
unsigned long high;
int err;
@@ -5002,6 +5003,11 @@ static ssize_t memory_high_write(struct kernfs_open_file *of,
memcg->high = high;
+ nr_pages = page_counter_read(&memcg->memory);
+ if (nr_pages > high)
+ try_to_free_mem_cgroup_pages(memcg, nr_pages - high,
+ GFP_KERNEL, true);
+
memcg_wb_domain_size_changed(memcg);
return nbytes;
}