[PATCH] mm, memcg: reset low limit during memcg offlining

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



A removed memory cgroup with a defined low limit and some belonging
pagecache has very low chances to be freed.

If a cgroup has been removed, there is likely no memory pressure inside
the cgroup, and the pagecache is protected from the external pressure
by the defined low limit. The cgroup will be freed only after
the reclaim of all belonging pages. And it will not happen until
there are any reclaimable memory in the system. That means,
there is a good chance, that a cold pagecache will reside
in the memory for an undefined amount of time, wasting
system resources.

Fix this issue by zeroing memcg->low during memcg offlining.

Signed-off-by: Roman Gushchin <guro@xxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
Cc: kernel-team@xxxxxx
Cc: cgroups@xxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
 mm/memcontrol.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index aed11b2d0251..2aa204b8f9fd 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4300,6 +4300,8 @@ static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
 	}
 	spin_unlock(&memcg->event_list_lock);
 
+	memcg->low = 0;
+
 	memcg_offline_kmem(memcg);
 	wb_memcg_offline(memcg);
 
-- 
2.13.3

--
To unsubscribe from this list: send the line "unsubscribe cgroups" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Security]     [Bugtraq]     [Linux OMAP]     [Linux MIPS]     [eCos]     [Asterisk Internet PBX]     [Linux API]     [Monitors]

  Powered by Linux