From: Michal Hocko <mhocko@kernel.org>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
jasowang@redhat.com, jani.nikula@linux.intel.com,
joonas.lahtinen@linux.intel.com, rodrigo.vivi@intel.com,
airlied@linux.ie, paulmck@linux.vnet.ibm.com,
josh@joshtriplett.org, rostedt@goodmis.org,
mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com,
virtualization@lists.linux-foundation.org,
intel-gfx@lists.freedesktop.org, linux-mm@kvack.org
Subject: Re: [RFC] [PATCH] mm,oom: Offload OOM notify callback to a kernel thread.
Date: Mon, 2 Oct 2017 16:19:00 +0200 [thread overview]
Message-ID: <20171002141900.acmcbilwhqethfhq@dhcp22.suse.cz> (raw)
In-Reply-To: <20171002170642-mutt-send-email-mst@kernel.org>
On Mon 02-10-17 17:11:55, Michael S. Tsirkin wrote:
> On Mon, Oct 02, 2017 at 01:50:35PM +0200, Michal Hocko wrote:
[...]
> > and some
> > other call path is allocating while holding the lock. But you seem to be
> > right and
> > leak_balloon
> > tell_host
> > virtqueue_add_outbuf
> > virtqueue_add
> >
> > can do GFP_KERNEL allocation and this is clearly wrong. Nobody should
> > try to allocate while we are in the OOM path. Michael, is there any way
> > to drop this?
>
> Yes - in practice it won't ever allocate - that path is never taken
> with add_outbuf - it is for add_sgs only.
>
> IMHO the issue is balloon inflation which needs to allocate
> memory. It does it under a mutex, and oom handler tries to take the
> same mutex.
try_lock for the oom notifier path should heal the problem then, righ?
At least for as a quick fix.
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2017-10-02 14:19 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-11 10:27 mm, virtio: possible OOM lockup at virtballoon_oom_notify() Tetsuo Handa
2017-09-29 4:00 ` Michael S. Tsirkin
2017-09-29 4:44 ` Tetsuo Handa
2017-10-01 5:44 ` [RFC] [PATCH] mm, oom: Offload OOM notify callback to a kernel thread Tetsuo Handa
2017-10-02 3:59 ` [RFC] [PATCH] mm,oom: " Michael S. Tsirkin
2017-10-02 9:06 ` Michal Hocko
2017-10-02 11:33 ` [RFC] [PATCH] mm, oom: " Tetsuo Handa
2017-10-02 11:50 ` Michal Hocko
2017-10-02 13:05 ` [RFC] [PATCH] mm,oom: " Tetsuo Handa
2017-10-02 13:13 ` Michal Hocko
2017-10-02 13:52 ` Tetsuo Handa
2017-10-02 14:23 ` Michael S. Tsirkin
2017-10-02 14:44 ` Tetsuo Handa
2017-10-07 11:30 ` Tetsuo Handa
2017-10-09 7:46 ` Michal Hocko
2017-10-09 8:06 ` Tetsuo Handa
2017-10-09 12:28 ` Michal Hocko
2017-10-09 13:31 ` Tetsuo Handa
2017-10-09 13:37 ` Michal Hocko
2017-10-09 14:24 ` Michael S. Tsirkin
2017-10-02 14:15 ` Michael S. Tsirkin
2017-10-02 14:11 ` Michael S. Tsirkin
2017-10-02 14:19 ` Michal Hocko [this message]
2017-10-02 14:29 ` Michael S. Tsirkin
2017-10-02 14:31 ` Michal Hocko
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