From: Oleg Nesterov <oleg@redhat.com>
To: David Rientjes <rientjes@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Rik van Riel <riel@redhat.com>,
linux-mm@kvack.org
Subject: Re: [patch 2/2] oom: kill all threads sharing oom killed task's mm
Date: Mon, 16 Aug 2010 08:00:49 +0200 [thread overview]
Message-ID: <20100816060049.GB9498@redhat.com> (raw)
In-Reply-To: <alpine.DEB.2.00.1008151425271.8727@chino.kir.corp.google.com>
On 08/15, David Rientjes wrote:
>
> On Sun, 15 Aug 2010, Oleg Nesterov wrote:
>
> > Again, I do not know how the code looks without the patch, but
>
> Why not? This series is based on Linus' tree.
OK, thanks...
> > > + do_each_thread(g, q) {
> > > + if (q->mm == mm && !same_thread_group(q, p))
> > > + force_sig(SIGKILL, q);
> > > + } while_each_thread(g, q);
> >
> > We can kill the wrong task. "q->mm == mm" doesn't necessarily mean
> > we found the task which shares ->mm with p (see above).
> >
> > This needs atomic_inc(mm_users). And please do not use do_each_thread.
>
> Instead of using mm_users to pin the mm, we could simply do this iteration
> with for_each_process() before sending the SIGKILL to p.
Yes, this should work too. (I'd prefer to not take ->siglock under
task->alloc_lock, but currently this is correct and happens anyway).
Oleg.
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next prev parent reply other threads:[~2010-08-16 6:03 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-15 4:30 [patch 1/2] oom: avoid killing a task if a thread sharing its mm cannot be killed David Rientjes
2010-08-15 4:31 ` [patch 2/2] oom: kill all threads sharing oom killed task's mm David Rientjes
2010-08-15 15:45 ` Oleg Nesterov
2010-08-15 21:28 ` David Rientjes
2010-08-16 6:00 ` Oleg Nesterov [this message]
2010-08-15 15:18 ` [patch 1/2] oom: avoid killing a task if a thread sharing its mm cannot be killed Oleg Nesterov
2010-08-15 21:23 ` David Rientjes
2010-08-16 5:52 ` Oleg Nesterov
2010-08-16 10:56 ` David Rientjes
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