From: Oleg Nesterov <oleg@redhat.com> To: David Rientjes <rientjes@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>, LKML <linux-kernel@vger.kernel.org>, linux-mm <linux-mm@kvack.org>, Andrew Morton <akpm@linux-foundation.org>, KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>, Nick Piggin <npiggin@suse.de> Subject: Re: [PATCH 1/5] oom: select_bad_process: check PF_KTHREAD instead of !mm to skip kthreads Date: Thu, 3 Jun 2010 16:27:17 +0200 [thread overview] Message-ID: <20100603142717.GC3548@redhat.com> (raw) In-Reply-To: <alpine.DEB.2.00.1006021437010.4765@chino.kir.corp.google.com> On 06/02, David Rientjes wrote: > > On Wed, 2 Jun 2010, Oleg Nesterov wrote: > > > > This isn't a bugfix, it simply prevents a recall to the oom killer after > > > the kthread has called unuse_mm(). Please show where any side effects of > > > oom killing a kthread, which cannot exit, as a result of use_mm() causes a > > > problem _anywhere_. > > > > I already showed you the side effects, but you removed this part in your > > reply. > > > > From http://marc.info/?l=linux-kernel&m=127542732121077 > > > > It can't die but force_sig() does bad things which shouldn't be done > > with workqueue thread. Note that it removes SIG_IGN, sets > > SIGNAL_GROUP_EXIT, makes signal_pending/fatal_signal_pedning true, etc. > > > > A workqueue thread must not run with SIGNAL_GROUP_EXIT set, SIGKILL > > must be ignored, signal_pending() must not be true. > > > > This is bug. It is minor, agreed, currently use_mm() is only used by aio. > > It's a problem that would probably never happen in practice because No need to convince me this bug is minor. I repeated this every time. I only argued with the "isn't a bugfix, no side effects". > considered the ideal task to kill. If you think this is rc material, then > push it to Andrew and say that. No, I don't think it is strictly necessary to push this fix into rc. But I don't understand why this matters. And in any case, when it comes to oom, I am in no position to make any authoritative decisions. David, I don't understand why do you refuse to re-diff your changes on top of Kosaki's work. If nothing else, this will help to review your changes. Oleg.
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From: Oleg Nesterov <oleg@redhat.com> To: David Rientjes <rientjes@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>, LKML <linux-kernel@vger.kernel.org>, linux-mm <linux-mm@kvack.org>, Andrew Morton <akpm@linux-foundation.org>, KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>, Nick Piggin <npiggin@suse.de> Subject: Re: [PATCH 1/5] oom: select_bad_process: check PF_KTHREAD instead of !mm to skip kthreads Date: Thu, 3 Jun 2010 16:27:17 +0200 [thread overview] Message-ID: <20100603142717.GC3548@redhat.com> (raw) In-Reply-To: <alpine.DEB.2.00.1006021437010.4765@chino.kir.corp.google.com> On 06/02, David Rientjes wrote: > > On Wed, 2 Jun 2010, Oleg Nesterov wrote: > > > > This isn't a bugfix, it simply prevents a recall to the oom killer after > > > the kthread has called unuse_mm(). Please show where any side effects of > > > oom killing a kthread, which cannot exit, as a result of use_mm() causes a > > > problem _anywhere_. > > > > I already showed you the side effects, but you removed this part in your > > reply. > > > > From http://marc.info/?l=linux-kernel&m=127542732121077 > > > > It can't die but force_sig() does bad things which shouldn't be done > > with workqueue thread. Note that it removes SIG_IGN, sets > > SIGNAL_GROUP_EXIT, makes signal_pending/fatal_signal_pedning true, etc. > > > > A workqueue thread must not run with SIGNAL_GROUP_EXIT set, SIGKILL > > must be ignored, signal_pending() must not be true. > > > > This is bug. It is minor, agreed, currently use_mm() is only used by aio. > > It's a problem that would probably never happen in practice because No need to convince me this bug is minor. I repeated this every time. I only argued with the "isn't a bugfix, no side effects". > considered the ideal task to kill. If you think this is rc material, then > push it to Andrew and say that. No, I don't think it is strictly necessary to push this fix into rc. But I don't understand why this matters. And in any case, when it comes to oom, I am in no position to make any authoritative decisions. David, I don't understand why do you refuse to re-diff your changes on top of Kosaki's work. If nothing else, this will help to review your changes. Oleg. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2010-06-03 14:28 UTC|newest] Thread overview: 110+ messages / expand[flat|nested] mbox.gz Atom feed top 2010-05-31 9:33 [PATCH 1/5] oom: select_bad_process: check PF_KTHREAD instead of !mm to skip kthreads KOSAKI Motohiro 2010-05-31 9:33 ` KOSAKI Motohiro 2010-05-31 9:35 ` [PATCH 2/5] oom: select_bad_process: PF_EXITING check should take ->mm into account KOSAKI Motohiro 2010-05-31 9:35 ` KOSAKI Motohiro 2010-05-31 16:43 ` Oleg Nesterov 2010-05-31 16:43 ` Oleg Nesterov 2010-06-01 1:10 ` KOSAKI Motohiro 2010-06-01 1:10 ` KOSAKI Motohiro 2010-06-01 20:18 ` Oleg Nesterov 2010-06-01 20:18 ` Oleg Nesterov 2010-06-02 13:54 ` [PATCH] oom: remove PF_EXITING check completely KOSAKI Motohiro 2010-06-02 13:54 ` KOSAKI Motohiro 2010-06-02 15:54 ` Oleg Nesterov 2010-06-02 15:54 ` Oleg Nesterov 2010-06-02 21:02 ` David Rientjes 2010-06-02 21:02 ` David Rientjes 2010-06-03 4:48 ` KOSAKI Motohiro 2010-06-03 4:48 ` KOSAKI Motohiro 2010-06-03 6:29 ` David Rientjes 2010-06-03 6:29 ` David Rientjes 2010-06-02 13:54 ` [PATCH] oom: Make coredump interruptible KOSAKI Motohiro 2010-06-02 13:54 ` KOSAKI Motohiro 2010-06-02 15:42 ` Oleg Nesterov 2010-06-02 15:42 ` Oleg Nesterov 2010-06-02 17:29 ` Roland McGrath 2010-06-02 17:29 ` Roland McGrath 2010-06-02 17:53 ` Oleg Nesterov 2010-06-02 17:53 ` Oleg Nesterov 2010-06-02 18:58 ` Roland McGrath 2010-06-02 18:58 ` Roland McGrath 2010-06-02 20:38 ` Oleg Nesterov 2010-06-02 20:38 ` Oleg Nesterov 2010-06-03 14:03 ` Oleg Nesterov 2010-06-03 14:03 ` Oleg Nesterov 2010-06-04 10:54 ` KOSAKI Motohiro 2010-06-04 10:54 ` KOSAKI Motohiro 2010-06-04 11:27 ` Oleg Nesterov 2010-06-04 11:27 ` Oleg Nesterov 2010-06-04 11:34 ` Oleg Nesterov 2010-06-04 11:34 ` Oleg Nesterov 2010-06-09 19:53 ` Oleg Nesterov 2010-06-09 19:53 ` Oleg Nesterov 2010-06-09 20:41 ` David Rientjes 2010-06-09 20:41 ` David Rientjes 2010-06-09 21:03 ` Oleg Nesterov 2010-06-09 21:03 ` Oleg Nesterov 2010-06-13 11:24 ` KOSAKI Motohiro 2010-06-13 11:24 ` KOSAKI Motohiro 2010-06-13 15:53 ` Oleg Nesterov 2010-06-13 15:53 ` Oleg Nesterov 2010-06-13 17:13 ` uninterruptible CLONE_VFORK (Was: oom: Make coredump interruptible) Oleg Nesterov 2010-06-13 17:13 ` Oleg Nesterov 2010-06-14 0:56 ` Roland McGrath 2010-06-14 0:56 ` Roland McGrath 2010-06-14 16:33 ` Oleg Nesterov 2010-06-14 16:33 ` Oleg Nesterov 2010-06-14 19:17 ` Roland McGrath 2010-06-14 19:17 ` Roland McGrath 2010-06-28 17:33 ` Oleg Nesterov 2010-06-28 17:33 ` Oleg Nesterov 2010-06-28 18:04 ` Roland McGrath 2010-06-28 18:04 ` Roland McGrath 2010-06-14 0:36 ` [PATCH] oom: Make coredump interruptible Roland McGrath 2010-06-14 0:36 ` Roland McGrath 2010-06-14 0:26 ` Roland McGrath 2010-06-14 0:26 ` Roland McGrath 2010-06-01 20:39 ` [PATCH 2/5] oom: select_bad_process: PF_EXITING check should take ->mm into account David Rientjes 2010-06-01 20:39 ` David Rientjes 2010-05-31 9:36 ` [PATCH 3/5] oom: introduce find_lock_task_mm() to fix !mm false positives KOSAKI Motohiro 2010-05-31 9:36 ` KOSAKI Motohiro 2010-06-01 0:57 ` KAMEZAWA Hiroyuki 2010-06-01 0:57 ` KAMEZAWA Hiroyuki 2010-06-01 20:42 ` David Rientjes 2010-06-01 20:42 ` David Rientjes 2010-06-02 16:05 ` Minchan Kim 2010-06-02 16:05 ` Minchan Kim 2010-05-31 9:37 ` [PATCH 4/5] oom: the points calculation of child processes must use find_lock_task_mm() too KOSAKI Motohiro 2010-05-31 9:37 ` KOSAKI Motohiro 2010-05-31 16:56 ` Oleg Nesterov 2010-05-31 16:56 ` Oleg Nesterov 2010-05-31 23:48 ` KOSAKI Motohiro 2010-05-31 23:48 ` KOSAKI Motohiro 2010-05-31 9:38 ` [PATCH 5/5] oom: __oom_kill_task() " KOSAKI Motohiro 2010-05-31 9:38 ` KOSAKI Motohiro 2010-06-01 1:02 ` KAMEZAWA Hiroyuki 2010-06-01 1:02 ` KAMEZAWA Hiroyuki 2010-06-01 20:44 ` David Rientjes 2010-06-01 20:44 ` David Rientjes 2010-06-01 0:54 ` [PATCH 1/5] oom: select_bad_process: check PF_KTHREAD instead of !mm to skip kthreads KAMEZAWA Hiroyuki 2010-06-01 0:54 ` KAMEZAWA Hiroyuki 2010-06-01 20:36 ` David Rientjes 2010-06-01 20:36 ` David Rientjes 2010-06-01 21:20 ` Oleg Nesterov 2010-06-01 21:20 ` Oleg Nesterov 2010-06-01 21:26 ` David Rientjes 2010-06-01 21:26 ` David Rientjes 2010-06-02 13:54 ` KOSAKI Motohiro 2010-06-02 13:54 ` KOSAKI Motohiro 2010-06-02 21:09 ` David Rientjes 2010-06-02 21:09 ` David Rientjes 2010-06-02 21:33 ` Oleg Nesterov 2010-06-02 21:33 ` Oleg Nesterov 2010-06-02 21:46 ` David Rientjes 2010-06-02 21:46 ` David Rientjes 2010-06-03 14:27 ` Oleg Nesterov [this message] 2010-06-03 14:27 ` Oleg Nesterov 2010-06-03 20:11 ` David Rientjes 2010-06-03 20:11 ` David Rientjes 2010-06-02 15:32 ` Minchan Kim 2010-06-02 15:32 ` Minchan Kim
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