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authorYang Shi <yang.shi@linux.alibaba.com>2019-01-16 07:51:35 +0800
committerJonathan Corbet <corbet@lwn.net>2019-01-16 14:51:38 -0700
commit053bc5693863d9230f9a11b923ea713aa6a4ce91 (patch)
parentb631c7f513548f4097687603ef6f959ccae18da9 (diff)
doc: memcontrol: fix the obsolete content about force empty
We don't do page cache reparent anymore when offlining memcg, so update force empty related content accordingly. Reviewed-by: Shakeel Butt <shakeelb@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
1 files changed, 4 insertions, 3 deletions
diff --git a/Documentation/cgroup-v1/memory.txt b/Documentation/cgroup-v1/memory.txt
index 3682e99234c2..8e2cb1dabeb0 100644
--- a/Documentation/cgroup-v1/memory.txt
+++ b/Documentation/cgroup-v1/memory.txt
@@ -70,7 +70,7 @@ Brief summary of control files.
memory.soft_limit_in_bytes # set/show soft limit of memory usage
memory.stat # show various statistics
memory.use_hierarchy # set/show hierarchical account enabled
- memory.force_empty # trigger forced move charge to parent
+ memory.force_empty # trigger forced page reclaim
memory.pressure_level # set memory pressure notifications
memory.swappiness # set/show swappiness parameter of vmscan
(See sysctl's vm.swappiness)
@@ -459,8 +459,9 @@ About use_hierarchy, see Section 6.
the cgroup will be reclaimed and as many pages reclaimed as possible.
The typical use case for this interface is before calling rmdir().
- Because rmdir() moves all pages to parent, some out-of-use page caches can be
- moved to the parent. If you want to avoid that, force_empty will be useful.
+ Though rmdir() offlines memcg, but the memcg may still stay there due to
+ charged file caches. Some out-of-use page caches may keep charged until
+ memory pressure happens. If you want to avoid that, force_empty will be useful.
Also, note that when memory.kmem.limit_in_bytes is set the charges due to
kernel pages will still be seen. This is not considered a failure and the