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From: Michal Hocko <mhocko@kernel.org>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
	Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
	Oleg Nesterov <oleg@redhat.com>,
	David Rientjes <rientjes@google.com>,
	Vladimir Davydov <vdavydov@parallels.com>
Subject: Re: [PATCH 09/10] vhost, mm: make sure that oom_reaper doesn't reap memory read by vhost
Date: Fri, 12 Aug 2016 11:43:19 +0200	[thread overview]
Message-ID: <20160812094319.GG3639@dhcp22.suse.cz> (raw)
In-Reply-To: <20160729161039-mutt-send-email-mst@kernel.org>

On Fri 29-07-16 16:14:10, Michael S. Tsirkin wrote:
> On Fri, Jul 29, 2016 at 08:04:22AM +0200, Michal Hocko wrote:
> > On Thu 28-07-16 23:41:53, Michael S. Tsirkin wrote:
[...]
> > > 
> > > > +	 */
> > > > +	set_bit(MMF_UNSTABLE, &mm->flags);
> > > > +
> > > 
> > > I would really prefer a callback that vhost would register
> > > and stop all accesses. Tell me if you need help on above idea.
> > 
> > 
> > Well, in order to make callback workable the oom reaper would have to
> > synchronize with the said callback until it declares all currently
> > ongoing accesses done. That means oom reaper would have to block/wait
> > and that is something I would really like to prevent from because it
> > just adds another possibility of the lockup (say the get_user cannot
> > make forward progress because it is stuck in the page fault allocating
> > memory). Or do you see any other way how to implement such a callback
> > mechanism without blocking on the oom_reaper side?
> 
> I'll think it over and respond.

ping?
-- 
Michal Hocko
SUSE Labs

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  parent reply	other threads:[~2016-08-12  9:43 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-28 19:42 [RFC PATCH 0/10] fortify oom killer even more Michal Hocko
2016-07-28 19:42 ` [PATCH 01/10] mm,oom_reaper: Reduce find_lock_task_mm() usage Michal Hocko
2016-07-28 19:42 ` [PATCH 02/10] mm,oom_reaper: Do not attempt to reap a task twice Michal Hocko
2016-07-28 19:42 ` [PATCH 03/10] oom: keep mm of the killed task available Michal Hocko
2016-07-28 19:42 ` [PATCH 04/10] mm, oom: get rid of signal_struct::oom_victims Michal Hocko
2016-07-28 19:42 ` [PATCH 05/10] kernel, oom: fix potential pgd_lock deadlock from __mmdrop Michal Hocko
2016-07-28 19:42 ` [PATCH 06/10] oom, suspend: fix oom_killer_disable vs. pm suspend properly Michal Hocko
2016-07-28 19:42 ` [PATCH 07/10] mm, oom: enforce exit_oom_victim on current task Michal Hocko
2016-07-28 19:42 ` [PATCH 08/10] exit, oom: postpone exit_oom_victim to later Michal Hocko
2016-07-30  8:20   ` Tetsuo Handa
2016-07-31  9:35     ` Michal Hocko
2016-07-31 10:19       ` Michal Hocko
2016-08-01 10:46       ` Tetsuo Handa
2016-08-01 11:33         ` Michal Hocko
2016-08-02 10:32           ` Tetsuo Handa
2016-08-02 11:31             ` Michal Hocko
2016-07-28 19:42 ` [PATCH 09/10] vhost, mm: make sure that oom_reaper doesn't reap memory read by vhost Michal Hocko
2016-07-28 20:41   ` Michael S. Tsirkin
2016-07-29  6:04     ` Michal Hocko
2016-07-29 13:14       ` Michael S. Tsirkin
2016-07-29 13:35         ` Michal Hocko
2016-07-29 17:57           ` Michael S. Tsirkin
2016-07-31  9:44             ` Michal Hocko
2016-08-12  9:42               ` Michal Hocko
2016-08-12 13:21                 ` Oleg Nesterov
2016-08-12 14:41                   ` Michal Hocko
2016-08-12 16:05                     ` Oleg Nesterov
2016-08-12 15:57                   ` Paul E. McKenney
2016-08-12 16:09                     ` Oleg Nesterov
2016-08-12 16:26                       ` Paul E. McKenney
2016-08-12 16:23                     ` Michal Hocko
2016-08-13  0:15                   ` Michael S. Tsirkin
2016-08-14  8:41                     ` Michal Hocko
2016-08-14 16:57                       ` Michael S. Tsirkin
2016-08-14 23:06                         ` Michael S. Tsirkin
2016-08-15  9:49                           ` Michal Hocko
2016-08-17 16:58                             ` Michal Hocko
2016-08-22 13:03                   ` Michal Hocko
2016-08-22 21:01                     ` Michael S. Tsirkin
2016-08-23  7:55                       ` Michal Hocko
2016-08-23  9:06                         ` Michal Hocko
2016-08-23 12:54                           ` Michael S. Tsirkin
2016-08-24 16:42                           ` Michal Hocko
2016-08-12  9:43         ` Michal Hocko [this message]
2016-07-29 17:07   ` Oleg Nesterov
2016-07-31  9:11     ` Michal Hocko
2016-07-28 19:42 ` [PATCH 10/10] oom, oom_reaper: allow to reap mm shared by the kthreads Michal Hocko

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