From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@suse.cz>,
linux-mm@kvack.org
Subject: Re: [PATCH 2/4] memcg: fix NULL mem_cgroup_try_charge
Date: Thu, 5 Jan 2012 14:56:46 +0900 [thread overview]
Message-ID: <20120105145646.40a47300.kamezawa.hiroyu@jp.fujitsu.com> (raw)
In-Reply-To: <alpine.LSU.2.00.1112281620400.8257@eggly.anvils>
On Wed, 28 Dec 2011 16:21:57 -0800 (PST)
Hugh Dickins <hughd@google.com> wrote:
> There is one way out of __mem_cgroup_try_charge() which claims success
> but still leaves memcg NULL, causing oops thereafter: make sure that
> it is set to root_mem_cgroup in this case.
>
> Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: KAMEZWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> ---
> Fix to memcg: return -EINTR at bypassing try_charge()
>
> mm/memcontrol.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> --- mmotm.orig/mm/memcontrol.c 2011-12-28 12:53:23.420367847 -0800
> +++ mmotm/mm/memcontrol.c 2011-12-28 14:41:19.803018025 -0800
> @@ -2263,7 +2263,9 @@ again:
> * task-struct. So, mm->owner can be NULL.
> */
> memcg = mem_cgroup_from_task(p);
> - if (!memcg || mem_cgroup_is_root(memcg)) {
> + if (!memcg)
> + memcg = root_mem_cgroup;
> + if (mem_cgroup_is_root(memcg)) {
> rcu_read_unlock();
> goto done;
> }
>
--
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next prev parent reply other threads:[~2012-01-05 5:57 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-29 0:17 [PATCH 0/4] memcg: four fixes to current next Hugh Dickins
2011-12-29 0:20 ` [PATCH 1/4] memcg: fix split_huge_page_refcounts Hugh Dickins
2012-01-05 5:55 ` KAMEZAWA Hiroyuki
2011-12-29 0:21 ` [PATCH 2/4] memcg: fix NULL mem_cgroup_try_charge Hugh Dickins
2012-01-05 5:56 ` KAMEZAWA Hiroyuki [this message]
2011-12-29 0:23 ` [PATCH 3/4] memcg: fix page migration to reset_owner Hugh Dickins
2012-01-05 6:00 ` KAMEZAWA Hiroyuki
2011-12-29 0:26 ` [PATCH 4/4] memcg: fix mem_cgroup_print_bad_page Hugh Dickins
2012-01-05 6:01 ` KAMEZAWA Hiroyuki
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