From: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@suse.cz>,
David Rientjes <rientjes@google.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
azurIt <azurit@pobox.sk>,
linux-mm@kvack.org, cgroups@vger.kernel.org, x86@kernel.org,
linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
kosaki.motohiro@gmail.com
Subject: Re: [patch 4/6] x86: finish user fault error path with fatal signal
Date: Mon, 29 Jul 2013 15:01:00 -0400 [thread overview]
Message-ID: <51F6BBEC.5070203@gmail.com> (raw)
In-Reply-To: <1374791138-15665-5-git-send-email-hannes@cmpxchg.org>
(7/25/13 6:25 PM), Johannes Weiner wrote:
> The x86 fault handler bails in the middle of error handling when the
> task has a fatal signal pending. For a subsequent patch this is a
> problem in OOM situations because it relies on
> pagefault_out_of_memory() being called even when the task has been
> killed, to perform proper per-task OOM state unwinding.
>
> Shortcutting the fault like this is a rather minor optimization that
> saves a few instructions in rare cases. Just remove it for
> user-triggered faults.
>
> Use the opportunity to split the fault retry handling from actual
> fault errors and add locking documentation that reads suprisingly
> similar to ARM's.
>
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
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WARNING: multiple messages have this Message-ID (diff)
From: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@suse.cz>,
David Rientjes <rientjes@google.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
azurIt <azurit@pobox.sk>,
linux-mm@kvack.org, cgroups@vger.kernel.org, x86@kernel.org,
linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
kosaki.motohiro@gmail.com
Subject: Re: [patch 4/6] x86: finish user fault error path with fatal signal
Date: Mon, 29 Jul 2013 15:01:00 -0400 [thread overview]
Message-ID: <51F6BBEC.5070203@gmail.com> (raw)
Message-ID: <20130729190100.DwApZ2vWf6vdAB23Ltf8B2Vwy0acBDlfafRHVfGSUYs@z> (raw)
In-Reply-To: <1374791138-15665-5-git-send-email-hannes@cmpxchg.org>
(7/25/13 6:25 PM), Johannes Weiner wrote:
> The x86 fault handler bails in the middle of error handling when the
> task has a fatal signal pending. For a subsequent patch this is a
> problem in OOM situations because it relies on
> pagefault_out_of_memory() being called even when the task has been
> killed, to perform proper per-task OOM state unwinding.
>
> Shortcutting the fault like this is a rather minor optimization that
> saves a few instructions in rare cases. Just remove it for
> user-triggered faults.
>
> Use the opportunity to split the fault retry handling from actual
> fault errors and add locking documentation that reads suprisingly
> similar to ARM's.
>
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
next prev parent reply other threads:[~2013-07-29 19:01 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-25 22:25 [patch 0/6] improve memcg oom killer robustness Johannes Weiner
2013-07-25 22:25 ` Johannes Weiner
2013-07-25 22:25 ` [patch 1/6] arch: mm: remove obsolete init OOM protection Johannes Weiner
2013-07-25 22:25 ` Johannes Weiner
2013-07-26 13:00 ` Michal Hocko
2013-07-26 13:00 ` Michal Hocko
2013-07-29 18:55 ` KOSAKI Motohiro
2013-07-29 18:55 ` KOSAKI Motohiro
2013-07-25 22:25 ` [patch 2/6] arch: mm: do not invoke OOM killer on kernel fault OOM Johannes Weiner
2013-07-25 22:25 ` Johannes Weiner
2013-07-26 13:07 ` Michal Hocko
2013-07-26 13:07 ` Michal Hocko
[not found] ` <1374791138-15665-3-git-send-email-hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
2013-07-29 18:58 ` KOSAKI Motohiro
2013-07-29 18:58 ` KOSAKI Motohiro
2013-07-29 18:58 ` KOSAKI Motohiro
2013-08-01 21:59 ` Johannes Weiner
2013-08-01 21:59 ` Johannes Weiner
2013-07-25 22:25 ` [patch 3/6] arch: mm: pass userspace fault flag to generic fault handler Johannes Weiner
2013-07-25 22:25 ` Johannes Weiner
[not found] ` <1374791138-15665-4-git-send-email-hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
2013-07-26 13:19 ` Michal Hocko
2013-07-26 13:19 ` Michal Hocko
2013-07-26 13:19 ` Michal Hocko
2013-07-26 18:45 ` Johannes Weiner
2013-07-26 18:45 ` Johannes Weiner
2013-07-25 22:25 ` [patch 4/6] x86: finish user fault error path with fatal signal Johannes Weiner
2013-07-25 22:25 ` Johannes Weiner
2013-07-26 13:52 ` Michal Hocko
2013-07-26 13:52 ` Michal Hocko
2013-07-26 18:46 ` Johannes Weiner
2013-07-26 18:46 ` Johannes Weiner
2013-07-29 12:45 ` Michal Hocko
2013-07-29 12:45 ` Michal Hocko
2013-07-29 19:01 ` KOSAKI Motohiro [this message]
2013-07-29 19:01 ` KOSAKI Motohiro
2013-07-25 22:25 ` [patch 5/6] mm: memcg: enable memcg OOM killer only for user faults Johannes Weiner
2013-07-25 22:25 ` Johannes Weiner
[not found] ` <1374791138-15665-6-git-send-email-hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
2013-07-26 14:16 ` Michal Hocko
2013-07-26 14:16 ` Michal Hocko
2013-07-26 14:16 ` Michal Hocko
2013-07-26 18:54 ` Johannes Weiner
2013-07-26 18:54 ` Johannes Weiner
2013-07-29 19:18 ` KOSAKI Motohiro
2013-07-29 19:18 ` KOSAKI Motohiro
[not found] ` <51F6C00C.5050702-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2013-07-29 19:44 ` Johannes Weiner
2013-07-29 19:44 ` Johannes Weiner
2013-07-29 19:44 ` Johannes Weiner
2013-07-29 19:47 ` KOSAKI Motohiro
2013-07-29 19:47 ` KOSAKI Motohiro
2013-07-25 22:25 ` [patch 6/6] mm: memcg: do not trap chargers with full callstack on OOM Johannes Weiner
2013-07-25 22:25 ` Johannes Weiner
[not found] ` <1374791138-15665-7-git-send-email-hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
2013-07-26 14:43 ` Michal Hocko
2013-07-26 14:43 ` Michal Hocko
2013-07-26 14:43 ` Michal Hocko
2013-07-26 21:28 ` Johannes Weiner
2013-07-26 21:28 ` Johannes Weiner
2013-07-29 14:12 ` Michal Hocko
2013-07-29 14:12 ` Michal Hocko
[not found] ` <20130729141250.GF4678-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2013-07-29 14:55 ` Johannes Weiner
2013-07-29 14:55 ` Johannes Weiner
2013-07-29 14:55 ` Johannes Weiner
[not found] ` <20130729145529.GW715-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
2013-07-29 15:52 ` Michal Hocko
2013-07-29 15:52 ` Michal Hocko
2013-07-29 15:52 ` Michal Hocko
[not found] ` <20130726212808.GD17975-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
2013-07-30 14:09 ` Michal Hocko
2013-07-30 14:09 ` Michal Hocko
2013-07-30 14:09 ` Michal Hocko
[not found] ` <20130730140913.GC15847-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2013-07-30 14:32 ` Johannes Weiner
2013-07-30 14:32 ` Johannes Weiner
2013-07-30 14:32 ` Johannes Weiner
[not found] ` <20130730143228.GD715-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
2013-07-30 14:56 ` Michal Hocko
2013-07-30 14:56 ` Michal Hocko
2013-07-30 14:56 ` Michal Hocko
2013-07-25 22:31 ` [patch 3.2] memcg OOM robustness (x86 only) Johannes Weiner
2013-07-25 22:31 ` Johannes Weiner
2013-08-03 8:38 ` azurIt
2013-08-03 8:38 ` azurIt
2013-08-03 16:30 ` Johannes Weiner
2013-08-03 16:30 ` Johannes Weiner
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