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authorVladimir Davydov <vdavydov@virtuozzo.com>2016-03-01 19:56:30 +0300
committerTejun Heo <tj@kernel.org>2016-03-01 12:06:02 -0500
commitfa06235b8eb0ae87a962e023243dba1eb4e7160d (patch)
treea2201788753596940ae690604fb82c594b518ba1
parent63253ad814db726d43c04011c752d83b7aaca998 (diff)
downloadlinux-fa06235b8eb0ae87a962e023243dba1eb4e7160d.tar.bz2
cgroup: reset css on destruction
An associated css can be around for quite a while after a cgroup directory has been removed. In general, it makes sense to reset it to defaults so as not to worry about any remnants. For instance, memory cgroup needs to reset memory.low, otherwise pages charged to a dead cgroup might never get reclaimed. There's ->css_reset callback, which would fit perfectly for the purpose. Currently, it's only called when a subsystem is disabled in the unified hierarchy and there are other subsystems dependant on it. Let's call it on css destruction as well. Suggested-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com> Signed-off-by: Tejun Heo <tj@kernel.org>
-rw-r--r--kernel/cgroup.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index fcfad82149b1..46529502e9d5 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -4787,6 +4787,9 @@ static void offline_css(struct cgroup_subsys_state *css)
if (!(css->flags & CSS_ONLINE))
return;
+ if (ss->css_reset)
+ ss->css_reset(css);
+
if (ss->css_offline)
ss->css_offline(css);