From fa06235b8eb0ae87a962e023243dba1eb4e7160d Mon Sep 17 00:00:00 2001 From: Vladimir Davydov Date: Tue, 1 Mar 2016 19:56:30 +0300 Subject: [PATCH] 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 Signed-off-by: Vladimir Davydov Signed-off-by: Tejun Heo --- kernel/cgroup.c | 3 +++ 1 file changed, 3 insertions(+) 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); -- 2.20.1