From mboxrd@z Thu Jan 1 00:00:00 1970 From: KOSAKI Motohiro Subject: Re: [patch 4/6] x86: finish user fault error path with fatal signal Date: Mon, 29 Jul 2013 15:01:00 -0400 Message-ID: <51F6BBEC.5070203@gmail.com> References: <1374791138-15665-1-git-send-email-hannes@cmpxchg.org> <1374791138-15665-5-git-send-email-hannes@cmpxchg.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1374791138-15665-5-git-send-email-hannes@cmpxchg.org> Sender: owner-linux-mm@kvack.org To: Johannes Weiner Cc: Andrew Morton , Michal Hocko , David Rientjes , KAMEZAWA Hiroyuki , azurIt , 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 List-Id: linux-arch.vger.kernel.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 Acked-by: KOSAKI Motohiro -- 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: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-vc0-f179.google.com ([209.85.220.179]:43919 "EHLO mail-vc0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751558Ab3G2TA2 (ORCPT ); Mon, 29 Jul 2013 15:00:28 -0400 Message-ID: <51F6BBEC.5070203@gmail.com> Date: Mon, 29 Jul 2013 15:01:00 -0400 From: KOSAKI Motohiro MIME-Version: 1.0 Subject: Re: [patch 4/6] x86: finish user fault error path with fatal signal References: <1374791138-15665-1-git-send-email-hannes@cmpxchg.org> <1374791138-15665-5-git-send-email-hannes@cmpxchg.org> In-Reply-To: <1374791138-15665-5-git-send-email-hannes@cmpxchg.org> Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: Johannes Weiner Cc: Andrew Morton , Michal Hocko , David Rientjes , KAMEZAWA Hiroyuki , azurIt , 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 Message-ID: <20130729190100.DwApZ2vWf6vdAB23Ltf8B2Vwy0acBDlfafRHVfGSUYs@z> (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 Acked-by: KOSAKI Motohiro