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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 /kernel/cgroup.c
parent63253ad814db726d43c04011c752d83b7aaca998 (diff)
downloadlinux-sh-fa06235b8eb0ae87a962e023243dba1eb4e7160d.tar.gz
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>
Diffstat (limited to 'kernel/cgroup.c')
-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);