From: David Rientjes <rientjes@google.com> To: Michal Hocko <mhocko@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org>, Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [patch] mm, oom: prevent additional oom kills before memory is freed Date: Thu, 15 Jun 2017 15:42:23 -0700 (PDT) [thread overview] Message-ID: <alpine.DEB.2.10.1706151534170.140219@chino.kir.corp.google.com> (raw) In-Reply-To: <20170615221236.GB22341@dhcp22.suse.cz> On Fri, 16 Jun 2017, Michal Hocko wrote: > I am sorry but I have really hard to make the oom reaper a reliable way > to stop all the potential oom lockups go away. I do not want to > reintroduce another potential lockup now. Please show where this "potential lockup" ever existed in a bug report or a testcase? I have never seen __mmput() block when trying to free the memory it maps. > I also do not see why any > solution should be rushed into. I have proposed a way to go and unless > it is clear that this is not a way forward then I simply do not agree > with any partial workarounds or shortcuts. This is not a shortcut, it is a bug fix. 4.12 kills 1-4 processes unnecessarily as a result of setting MMF_OOM_SKIP incorrectly before the mm's memory can be freed. If you have not seen this issue before, which is why you asked if I ever observed it in practice, then you have not stress tested oom reaping. It is very observable and reproducible. I do not agree that adding additional and obscure locking into __mmput() is the solution to what is plainly and obviously fixed with this simple patch. 4.12 needs to stop killing 2-5 processes on every oom condition instead of 1.
WARNING: multiple messages have this Message-ID (diff)
From: David Rientjes <rientjes@google.com> To: Michal Hocko <mhocko@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org>, Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [patch] mm, oom: prevent additional oom kills before memory is freed Date: Thu, 15 Jun 2017 15:42:23 -0700 (PDT) [thread overview] Message-ID: <alpine.DEB.2.10.1706151534170.140219@chino.kir.corp.google.com> (raw) In-Reply-To: <20170615221236.GB22341@dhcp22.suse.cz> On Fri, 16 Jun 2017, Michal Hocko wrote: > I am sorry but I have really hard to make the oom reaper a reliable way > to stop all the potential oom lockups go away. I do not want to > reintroduce another potential lockup now. Please show where this "potential lockup" ever existed in a bug report or a testcase? I have never seen __mmput() block when trying to free the memory it maps. > I also do not see why any > solution should be rushed into. I have proposed a way to go and unless > it is clear that this is not a way forward then I simply do not agree > with any partial workarounds or shortcuts. This is not a shortcut, it is a bug fix. 4.12 kills 1-4 processes unnecessarily as a result of setting MMF_OOM_SKIP incorrectly before the mm's memory can be freed. If you have not seen this issue before, which is why you asked if I ever observed it in practice, then you have not stress tested oom reaping. It is very observable and reproducible. I do not agree that adding additional and obscure locking into __mmput() is the solution to what is plainly and obviously fixed with this simple patch. 4.12 needs to stop killing 2-5 processes on every oom condition instead of 1. -- 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:[~2017-06-15 22:42 UTC|newest] Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-06-14 23:43 [patch] mm, oom: prevent additional oom kills before memory is freed David Rientjes 2017-06-14 23:43 ` David Rientjes 2017-06-15 10:39 ` Michal Hocko 2017-06-15 10:39 ` Michal Hocko 2017-06-15 10:53 ` Tetsuo Handa 2017-06-15 10:53 ` Tetsuo Handa 2017-06-15 11:01 ` Michal Hocko 2017-06-15 11:01 ` Michal Hocko 2017-06-15 11:32 ` Tetsuo Handa 2017-06-15 11:32 ` Tetsuo Handa 2017-06-15 12:03 ` Michal Hocko 2017-06-15 12:03 ` Michal Hocko 2017-06-15 12:13 ` Michal Hocko 2017-06-15 12:13 ` Michal Hocko 2017-06-15 13:01 ` Tetsuo Handa 2017-06-15 13:01 ` Tetsuo Handa 2017-06-15 13:22 ` Michal Hocko 2017-06-15 13:22 ` Michal Hocko 2017-06-15 21:43 ` Tetsuo Handa 2017-06-15 21:43 ` Tetsuo Handa 2017-06-15 21:37 ` David Rientjes 2017-06-15 21:37 ` David Rientjes 2017-06-15 12:20 ` Michal Hocko 2017-06-15 12:20 ` Michal Hocko 2017-06-15 21:26 ` David Rientjes 2017-06-15 21:26 ` David Rientjes 2017-06-15 21:41 ` Michal Hocko 2017-06-15 21:41 ` Michal Hocko 2017-06-15 22:03 ` David Rientjes 2017-06-15 22:03 ` David Rientjes 2017-06-15 22:12 ` Michal Hocko 2017-06-15 22:12 ` Michal Hocko 2017-06-15 22:42 ` David Rientjes [this message] 2017-06-15 22:42 ` David Rientjes 2017-06-16 8:06 ` Michal Hocko 2017-06-16 8:06 ` Michal Hocko 2017-06-16 0:54 ` Tetsuo Handa 2017-06-16 0:54 ` Tetsuo Handa 2017-06-16 4:00 ` Tetsuo Handa 2017-06-16 4:00 ` Tetsuo Handa 2017-06-16 8:39 ` Michal Hocko 2017-06-16 8:39 ` Michal Hocko 2017-06-16 10:27 ` Tetsuo Handa 2017-06-16 10:27 ` Tetsuo Handa 2017-06-16 11:02 ` Michal Hocko 2017-06-16 11:02 ` Michal Hocko 2017-06-16 14:26 ` Re: [patch] mm, oom: prevent additional oom kills before memoryis freed Tetsuo Handa 2017-06-16 14:26 ` Tetsuo Handa 2017-06-16 14:42 ` Michal Hocko 2017-06-16 14:42 ` Michal Hocko 2017-06-17 13:30 ` Re: [patch] mm, oom: prevent additional oom kills before memory is freed Tetsuo Handa 2017-06-17 13:30 ` Tetsuo Handa 2017-06-23 12:38 ` Michal Hocko 2017-06-23 12:38 ` Michal Hocko 2017-06-16 12:22 ` Tetsuo Handa 2017-06-16 12:22 ` Tetsuo Handa 2017-06-16 14:12 ` Michal Hocko 2017-06-16 14:12 ` Michal Hocko 2017-06-17 5:17 ` [PATCH] mm,oom_kill: Close race window of needlessly selecting new victims Tetsuo Handa 2017-06-17 5:17 ` Tetsuo Handa 2017-06-20 22:12 ` David Rientjes 2017-06-20 22:12 ` David Rientjes 2017-06-21 2:17 ` Tetsuo Handa 2017-06-21 20:31 ` David Rientjes 2017-06-21 20:31 ` David Rientjes 2017-06-22 0:53 ` Tetsuo Handa 2017-06-23 12:45 ` Michal Hocko 2017-06-23 12:45 ` Michal Hocko 2017-06-21 13:18 ` Michal Hocko 2017-06-21 13:18 ` Michal Hocko
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