From: Oleg Nesterov <oleg@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Hugh Dickins <hughd@google.com>,
linux-mm@kvack.org, Andrey Vagin <avagin@openvz.org>,
David Rientjes <rientjes@google.com>
Subject: [PATCH 0/3] oom: TIF_MEMDIE/PF_EXITING fixes
Date: Sat, 12 Mar 2011 14:43:41 +0100 [thread overview]
Message-ID: <20110312134341.GA27275@redhat.com> (raw)
In-Reply-To: <20110312123413.GA18351@redhat.com>
On 03/12, Oleg Nesterov wrote:
>
> On 03/11, David Rientjes wrote:
> >
> > On Wed, 9 Mar 2011, Andrew Morton wrote:
> >
> > > If Oleg's test program cause a hang with
> > > oom-prevent-unnecessary-oom-kills-or-kernel-panics.patch and doesn't
> > > cause a hang without
> > > oom-prevent-unnecessary-oom-kills-or-kernel-panics.patch then that's a
> > > big problem for
> > > oom-prevent-unnecessary-oom-kills-or-kernel-panics.patch, no?
> > >
> >
> > It's a problem, but not because of
> > oom-prevent-unnecessary-oom-kills-or-kernel-panics.patch.
>
> It is, afaics. oom-killer can't ussume that a single PF_EXITING && p->mm
> thread is going to free the memory.
>
> > If we don't
> > have this patch, then we have a trivial panic when an oom kill occurs in a
> > cpuset with no other eligible processes, the oom killed thread group
> > leader exits
>
> It is not clear what "leader exits" actually mean. OK, perhaps you mean
> its ->mm == NULL.
>
> > but its other threads do not and they trigger oom kills
> > themselves. for_each_process() does not iterate over these threads and so
> > it finds no eligible threads to kill and then panics
>
> Could you explain what do you mean? No need to kill these threads, they
> are already killed, we should wait until they all exit.
>
> > I'll look at Oleg's test case
> > and see what can be done to fix that condition, but the answer isn't to
> > ignore eligible threads that can be killed.
>
> Once again, they are already killed. Or I do not understand what you meant.
>
> Could you please explain the problem in more details?
>
>
> Also. Could you please look at the patches I sent?
>
> [PATCH 1/1] oom_kill_task: mark every thread as TIF_MEMDIE
> [PATCH v2 1/1] select_bad_process: improve the PF_EXITING check
Cough. And both were not right, while_each_thread(p, t) needs the properly
initialized "t". At least I warned they were not tested ;)
> Note also the note about "p == current" check. it should be fixed too.
I am resending the fixes above plus the new one.
David, Kosaki, what do you think?
Oleg.
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next prev parent reply other threads:[~2011-03-12 13:52 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-01 19:09 [patch] oom: prevent unnecessary oom kills or kernel panics David Rientjes
2011-03-03 1:20 ` KOSAKI Motohiro
2011-03-03 19:53 ` David Rientjes
2011-03-06 11:14 ` KOSAKI Motohiro
2011-03-06 22:06 ` David Rientjes
2011-03-08 0:24 ` KOSAKI Motohiro
2011-03-08 2:01 ` KOSAKI Motohiro
2011-03-08 13:42 ` Oleg Nesterov
2011-03-08 23:57 ` David Rientjes
2011-03-09 10:36 ` KOSAKI Motohiro
2011-03-09 11:06 ` Oleg Nesterov
2011-03-09 20:32 ` David Rientjes
2011-03-10 12:05 ` Oleg Nesterov
2011-03-10 15:40 ` [PATCH 0/1] Was: " Oleg Nesterov
2011-03-10 15:41 ` [PATCH 1/1] oom_kill_task: mark every thread as TIF_MEMDIE Oleg Nesterov
2011-03-13 1:08 ` David Rientjes
2011-03-10 16:36 ` [PATCH 0/1] select_bad_process: improve the PF_EXITING check Oleg Nesterov
2011-03-10 16:37 ` [PATCH 1/1] " Oleg Nesterov
2011-03-10 16:40 ` [PATCH 0/1] " Oleg Nesterov
2011-03-10 17:18 ` [PATCH v2 " Oleg Nesterov
2011-03-10 17:19 ` [PATCH v2 1/1] " Oleg Nesterov
2011-03-13 1:06 ` [patch] oom: prevent unnecessary oom kills or kernel panics David Rientjes
2011-03-09 23:19 ` Andrew Morton
2011-03-11 19:45 ` David Rientjes
2011-03-12 12:34 ` Oleg Nesterov
2011-03-12 13:43 ` Oleg Nesterov [this message]
2011-03-12 13:44 ` [PATCH 1/3] oom: oom_kill_task: mark every thread as TIF_MEMDIE Oleg Nesterov
2011-03-13 1:14 ` David Rientjes
2011-03-12 13:44 ` [PATCH 2/3] oom: select_bad_process: improve the PF_EXITING check Oleg Nesterov
2011-03-12 13:44 ` [PATCH 3/3] oom: select_bad_process: use same_thread_group() Oleg Nesterov
2011-03-12 19:40 ` [PATCH 0/3] oom: TIF_MEMDIE/PF_EXITING fixes Hugh Dickins
2011-03-13 8:53 ` KOSAKI Motohiro
2011-03-13 21:27 ` Oleg Nesterov
2011-03-14 19:04 ` [PATCH 0/3 for 2.6.38] oom: fixes Oleg Nesterov
2011-03-14 19:04 ` [PATCH 1/3 for 2.6.38] oom: oom_kill_process: don't set TIF_MEMDIE if !p->mm Oleg Nesterov
2011-03-14 19:35 ` Linus Torvalds
2011-03-14 20:31 ` Oleg Nesterov
2011-03-14 20:32 ` David Rientjes
2011-03-15 19:12 ` Oleg Nesterov
2011-03-15 19:51 ` David Rientjes
2011-03-14 20:22 ` David Rientjes
2011-03-15 18:53 ` Oleg Nesterov
2011-03-15 19:54 ` David Rientjes
2011-03-15 21:16 ` Oleg Nesterov
2011-03-14 19:05 ` [PATCH 2/3 for 2.6.38] oom: select_bad_process: ignore TIF_MEMDIE zombies Oleg Nesterov
2011-03-14 20:50 ` David Rientjes
2011-03-14 19:05 ` [PATCH 3/3 for 2.6.38] oom: oom_kill_process: fix the child_points logic Oleg Nesterov
2011-03-14 20:41 ` David Rientjes
2011-03-15 19:21 ` Oleg Nesterov
2011-03-13 11:36 ` [PATCH 0/3] oom: TIF_MEMDIE/PF_EXITING fixes KOSAKI Motohiro
2011-03-13 1:11 ` [patch] oom: prevent unnecessary oom kills or kernel panics David Rientjes
2011-03-13 1:15 ` [patch -mm] oom: avoid deferring oom killer if exiting task is being traced David Rientjes
2011-03-14 17:40 ` Oleg Nesterov
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