From: Vladimir Davydov <vdavydov@virtuozzo.com>
To: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
cgroups@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] cgroup: reset css on destruction
Date: Tue, 1 Mar 2016 19:56:30 +0300 [thread overview]
Message-ID: <20160301165630.GB2426@esperanza> (raw)
In-Reply-To: <20160301163018.GE3965@htj.duckdns.org>
On Tue, Mar 01, 2016 at 11:30:18AM -0500, Tejun Heo wrote:
> On Tue, Mar 01, 2016 at 02:13:13PM +0300, Vladimir Davydov wrote:
> > @@ -5138,6 +5138,8 @@ static void kill_css(struct cgroup_subsys_state *css)
> > * See seq_css() for details.
> > */
> > css_clear_dir(css, NULL);
> > + if (css->ss->css_reset)
> > + css->ss->css_reset(css);
>
> I think the better spot for this is in offline_css() right before
> ->css_offline() is called.
Okay, here it goes.
---
From: Vladimir Davydov <vdavydov@virtuozzo.com>
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 <hannes@cmpxchg.org>
Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index cc40463e7b69..bb1900b70b01 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -4876,6 +4876,9 @@ 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);
--
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next prev parent reply other threads:[~2016-03-01 16:56 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-01 11:13 [PATCH 1/2] mm: memcontrol: cleanup css_reset callback Vladimir Davydov
2016-03-01 11:13 ` [PATCH 2/2] cgroup: reset css on destruction Vladimir Davydov
2016-03-01 16:30 ` Tejun Heo
2016-03-01 16:56 ` Vladimir Davydov [this message]
2016-03-01 17:06 ` Tejun Heo
2016-03-01 19:54 ` Johannes Weiner
2016-03-01 16:04 ` [PATCH 1/2] mm: memcontrol: cleanup css_reset callback Michal Hocko
2016-03-01 19:53 ` Johannes Weiner
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