From: Johannes Weiner <hannes@xxxxxxxxxxx>
Subject: 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@xxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 6 ++++++
1 file changed, 6 insertions(+)
diff -puN mm/memcontrol.c~mm-memcontrol-reclaim-when-shrinking-memoryhigh-below-usage mm/memcontrol.c
--- a/mm/memcontrol.c~mm-memcontrol-reclaim-when-shrinking-memoryhigh-below-usage
+++ a/mm/memcontrol.c
@@ -4992,6 +4992,7 @@ static ssize_t memory_high_write(struct
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
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;
}
_
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html