From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
To: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
Cc: Michal Hocko <mhocko-AlSwsSmVLrQ@public.gmane.org>,
linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org,
cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>,
KAMEZAWA Hiroyuki
<kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>,
Balbir Singh
<bsingharora-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: Re: [PATCH 4/6] cgroups: forbid pre_destroy callback to fail
Date: Fri, 19 Oct 2012 13:17:36 -0700 [thread overview]
Message-ID: <20121019201736.GQ13370@google.com> (raw)
In-Reply-To: <50811E5E.1090205-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
On Fri, Oct 19, 2012 at 05:33:18PM +0800, Li Zefan wrote:
> On 2012/10/17 21:30, Michal Hocko wrote:
> > Now that mem_cgroup_pre_destroy callback doesn't fail finally we can
> > safely move on and forbit all the callbacks to fail. The last missing
> > piece is moving cgroup_call_pre_destroy after cgroup_clear_css_refs so
> > that css_tryget fails so no new charges for the memcg can happen.
>
> > The callbacks are also called from within cgroup_lock to guarantee that
> > no new tasks show up.
>
> I'm afraid this won't work. See commit 3fa59dfbc3b223f02c26593be69ce6fc9a940405
> ("cgroup: fix potential deadlock in pre_destroy")
Yeah, you're right. Argh... we really should unexport cgroup_lock
soon.
Thanks.
--
tejun
WARNING: multiple messages have this Message-ID (diff)
From: Tejun Heo <tj@kernel.org>
To: Li Zefan <lizefan@huawei.com>
Cc: Michal Hocko <mhocko@suse.cz>,
linux-mm@kvack.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org,
Johannes Weiner <hannes@cmpxchg.org>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Balbir Singh <bsingharora@gmail.com>
Subject: Re: [PATCH 4/6] cgroups: forbid pre_destroy callback to fail
Date: Fri, 19 Oct 2012 13:17:36 -0700 [thread overview]
Message-ID: <20121019201736.GQ13370@google.com> (raw)
In-Reply-To: <50811E5E.1090205@huawei.com>
On Fri, Oct 19, 2012 at 05:33:18PM +0800, Li Zefan wrote:
> On 2012/10/17 21:30, Michal Hocko wrote:
> > Now that mem_cgroup_pre_destroy callback doesn't fail finally we can
> > safely move on and forbit all the callbacks to fail. The last missing
> > piece is moving cgroup_call_pre_destroy after cgroup_clear_css_refs so
> > that css_tryget fails so no new charges for the memcg can happen.
>
> > The callbacks are also called from within cgroup_lock to guarantee that
> > no new tasks show up.
>
> I'm afraid this won't work. See commit 3fa59dfbc3b223f02c26593be69ce6fc9a940405
> ("cgroup: fix potential deadlock in pre_destroy")
Yeah, you're right. Argh... we really should unexport cgroup_lock
soon.
Thanks.
--
tejun
--
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WARNING: multiple messages have this Message-ID (diff)
From: Tejun Heo <tj@kernel.org>
To: Li Zefan <lizefan@huawei.com>
Cc: Michal Hocko <mhocko@suse.cz>,
linux-mm@kvack.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org,
Johannes Weiner <hannes@cmpxchg.org>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Balbir Singh <bsingharora@gmail.com>
Subject: Re: [PATCH 4/6] cgroups: forbid pre_destroy callback to fail
Date: Fri, 19 Oct 2012 13:17:36 -0700 [thread overview]
Message-ID: <20121019201736.GQ13370@google.com> (raw)
In-Reply-To: <50811E5E.1090205@huawei.com>
On Fri, Oct 19, 2012 at 05:33:18PM +0800, Li Zefan wrote:
> On 2012/10/17 21:30, Michal Hocko wrote:
> > Now that mem_cgroup_pre_destroy callback doesn't fail finally we can
> > safely move on and forbit all the callbacks to fail. The last missing
> > piece is moving cgroup_call_pre_destroy after cgroup_clear_css_refs so
> > that css_tryget fails so no new charges for the memcg can happen.
>
> > The callbacks are also called from within cgroup_lock to guarantee that
> > no new tasks show up.
>
> I'm afraid this won't work. See commit 3fa59dfbc3b223f02c26593be69ce6fc9a940405
> ("cgroup: fix potential deadlock in pre_destroy")
Yeah, you're right. Argh... we really should unexport cgroup_lock
soon.
Thanks.
--
tejun
next prev parent reply other threads:[~2012-10-19 20:17 UTC|newest]
Thread overview: 79+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-17 13:30 [RFC] memcg/cgroup: do not fail fail on pre_destroy callbacks Michal Hocko
2012-10-17 13:30 ` Michal Hocko
2012-10-17 13:30 ` [PATCH 1/6] memcg: split mem_cgroup_force_empty into reclaiming and reparenting parts Michal Hocko
2012-10-17 13:30 ` Michal Hocko
2012-10-18 21:56 ` Tejun Heo
2012-10-18 21:56 ` Tejun Heo
2012-10-17 13:30 ` [PATCH 2/6] memcg: root_cgroup cannot reach mem_cgroup_move_parent Michal Hocko
2012-10-17 13:30 ` Michal Hocko
[not found] ` <1350480648-10905-3-git-send-email-mhocko-AlSwsSmVLrQ@public.gmane.org>
2012-10-18 21:58 ` Tejun Heo
2012-10-18 21:58 ` Tejun Heo
2012-10-18 21:58 ` Tejun Heo
2012-10-17 13:30 ` [PATCH 3/6] memcg: Simplify mem_cgroup_force_empty_list error handling Michal Hocko
2012-10-17 13:30 ` Michal Hocko
2012-10-18 22:16 ` Tejun Heo
2012-10-18 22:16 ` Tejun Heo
[not found] ` <20121018221654.GP13370-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-19 13:24 ` Michal Hocko
2012-10-19 13:24 ` Michal Hocko
2012-10-19 13:24 ` Michal Hocko
[not found] ` <20121019132438.GD799-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2012-10-19 19:49 ` Tejun Heo
2012-10-19 19:49 ` Tejun Heo
2012-10-19 19:49 ` Tejun Heo
2012-10-17 13:30 ` [PATCH 4/6] cgroups: forbid pre_destroy callback to fail Michal Hocko
2012-10-17 13:30 ` Michal Hocko
2012-10-18 22:41 ` Tejun Heo
2012-10-18 22:41 ` Tejun Heo
[not found] ` <20121018224148.GR13370-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-18 22:46 ` Tejun Heo
2012-10-18 22:46 ` Tejun Heo
2012-10-18 22:46 ` Tejun Heo
[not found] ` <20121018224606.GS13370-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-19 13:34 ` Michal Hocko
2012-10-19 13:34 ` Michal Hocko
2012-10-19 13:34 ` Michal Hocko
2012-10-19 13:32 ` Michal Hocko
2012-10-19 13:32 ` Michal Hocko
2012-10-19 13:32 ` Michal Hocko
[not found] ` <20121019133244.GE799-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2012-10-19 20:24 ` Tejun Heo
2012-10-19 20:24 ` Tejun Heo
2012-10-19 20:24 ` Tejun Heo
[not found] ` <20121019202405.GR13370-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-10-22 10:30 ` Michal Hocko
2012-10-22 10:30 ` Michal Hocko
2012-10-22 10:30 ` Michal Hocko
2012-10-24 19:25 ` Tejun Heo
2012-10-24 19:25 ` Tejun Heo
[not found] ` <20121024192535.GG12182-OlzNCW9NnSVy/B6EtB590w@public.gmane.org>
2012-10-25 14:37 ` Michal Hocko
2012-10-25 14:37 ` Michal Hocko
2012-10-25 14:37 ` Michal Hocko
[not found] ` <20121025143756.GI11105-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2012-10-25 17:42 ` Tejun Heo
2012-10-25 17:42 ` Tejun Heo
2012-10-25 17:42 ` Tejun Heo
2012-10-25 18:48 ` Michal Hocko
2012-10-25 18:48 ` Michal Hocko
2012-10-19 9:33 ` Li Zefan
2012-10-19 9:33 ` Li Zefan
[not found] ` <50811E5E.1090205-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
2012-10-19 11:09 ` Michal Hocko
2012-10-19 11:09 ` Michal Hocko
2012-10-19 11:09 ` Michal Hocko
2012-10-19 20:17 ` Tejun Heo [this message]
2012-10-19 20:17 ` Tejun Heo
2012-10-19 20:17 ` Tejun Heo
2012-10-17 13:30 ` [PATCH 5/6] memcg: make mem_cgroup_reparent_charges non failing Michal Hocko
2012-10-17 13:30 ` Michal Hocko
2012-10-18 8:30 ` Li Zefan
2012-10-18 8:30 ` Li Zefan
2012-10-18 8:42 ` Michal Hocko
2012-10-18 8:42 ` Michal Hocko
2012-10-18 22:48 ` Tejun Heo
2012-10-18 22:48 ` Tejun Heo
2012-10-19 13:49 ` Michal Hocko
2012-10-19 13:49 ` Michal Hocko
2012-10-19 13:49 ` Michal Hocko
2012-10-17 13:30 ` [PATCH 6/6] hugetlb: do not fail in hugetlb_cgroup_pre_destroy Michal Hocko
2012-10-17 13:30 ` Michal Hocko
[not found] ` <1350480648-10905-7-git-send-email-mhocko-AlSwsSmVLrQ@public.gmane.org>
2012-10-18 22:48 ` Tejun Heo
2012-10-18 22:48 ` Tejun Heo
2012-10-18 22:48 ` Tejun Heo
2012-10-17 15:30 ` [RFC] memcg/cgroup: do not fail fail on pre_destroy callbacks Glauber Costa
2012-10-17 15:30 ` Glauber Costa
[not found] ` <1350480648-10905-1-git-send-email-mhocko-AlSwsSmVLrQ@public.gmane.org>
2012-10-18 0:29 ` Kamezawa Hiroyuki
2012-10-18 0:29 ` Kamezawa Hiroyuki
2012-10-18 0:29 ` Kamezawa Hiroyuki
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