From: Michal Hocko <mhocko@kernel.org>
To: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] mm: memcontrol: add sanity checks for memcg->id.ref on get/put
Date: Tue, 2 Aug 2016 17:51:21 +0200 [thread overview]
Message-ID: <20160802155120.GA28900@dhcp22.suse.cz> (raw)
In-Reply-To: <20160802124503.GK12403@dhcp22.suse.cz>
On Tue 02-08-16 14:45:03, Michal Hocko wrote:
> On Mon 01-08-16 16:26:26, Vladimir Davydov wrote:
> [...]
> > static struct mem_cgroup *mem_cgroup_id_get_active(struct mem_cgroup *memcg)
> > {
> > - while (!atomic_inc_not_zero(&memcg->id.ref))
> > + while (!atomic_inc_not_zero(&memcg->id.ref)) {
> > + VM_BUG_ON(mem_cgroup_is_root(memcg));
> > memcg = parent_mem_cgroup(memcg);
> > + }
>
> why is this BUG_ON ok? What if the root.use_hierarchy=true?
Scratch that. I got it. root will never get its count down to 0. Sorry
about the noise.
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2016-08-02 15:51 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-01 13:26 [PATCH 1/3] mm: memcontrol: fix swap counter leak on swapout from offline cgroup Vladimir Davydov
2016-08-01 13:26 ` [PATCH 2/3] mm: memcontrol: fix memcg id ref counter on swap charge move Vladimir Davydov
2016-08-02 12:34 ` Michal Hocko
2016-08-01 13:26 ` [PATCH 3/3] mm: memcontrol: add sanity checks for memcg->id.ref on get/put Vladimir Davydov
2016-08-02 12:45 ` Michal Hocko
2016-08-02 15:51 ` Michal Hocko [this message]
2016-08-02 12:23 ` [PATCH 1/3] mm: memcontrol: fix swap counter leak on swapout from offline cgroup Michal Hocko
2016-08-02 12:42 ` Michal Hocko
2016-08-02 13:22 ` Vladimir Davydov
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