From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with ESMTP id 8F6918D0040 for ; Wed, 23 Mar 2011 03:56:21 -0400 (EDT) Received: from m4.gw.fujitsu.co.jp (unknown [10.0.50.74]) by fgwmail6.fujitsu.co.jp (Postfix) with ESMTP id CF3F03EE0BD for ; Wed, 23 Mar 2011 16:56:18 +0900 (JST) Received: from smail (m4 [127.0.0.1]) by outgoing.m4.gw.fujitsu.co.jp (Postfix) with ESMTP id B117345DE56 for ; Wed, 23 Mar 2011 16:56:18 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (s4.gw.fujitsu.co.jp [10.0.50.94]) by m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 9711C45DE51 for ; Wed, 23 Mar 2011 16:56:18 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 81358E78002 for ; Wed, 23 Mar 2011 16:56:18 +0900 (JST) Received: from m106.s.css.fujitsu.com (m106.s.css.fujitsu.com [10.240.81.146]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 4AE991DB8037 for ; Wed, 23 Mar 2011 16:56:18 +0900 (JST) Date: Wed, 23 Mar 2011 16:49:49 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH 5/5] x86,mm: make pagefault killable Message-Id: <20110323164949.5be6aa48.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20110322200945.B06D.A69D9226@jp.fujitsu.com> References: <20110315153801.3526.A69D9226@jp.fujitsu.com> <20110322194721.B05E.A69D9226@jp.fujitsu.com> <20110322200945.B06D.A69D9226@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: KOSAKI Motohiro Cc: linux-kernel@vger.kernel.org, Andrew Morton , David Rientjes , Linus Torvalds , Rik van Riel , Oleg Nesterov , linux-mm , Andrey Vagin , Hugh Dickins On Tue, 22 Mar 2011 20:09:29 +0900 (JST) KOSAKI Motohiro wrote: > When oom killer occured, almost processes are getting stuck following > two points. > > 1) __alloc_pages_nodemask > 2) __lock_page_or_retry > > 1) is not much problematic because TIF_MEMDIE lead to make allocation > failure and get out from page allocator. 2) is more problematic. When > OOM situation, Zones typically don't have page cache at all and Memory > starvation might lead to reduce IO performance largely. When fork bomb > occur, TIF_MEMDIE task don't die quickly mean fork bomb may create > new process quickly rather than oom-killer kill it. Then, the system > may become livelock. > > This patch makes pagefault interruptible by SIGKILL. > > Signed-off-by: KOSAKI Motohiro > --- > arch/x86/mm/fault.c | 9 +++++++++ > include/linux/mm.h | 1 + > mm/filemap.c | 22 +++++++++++++++++----- > 3 files changed, 27 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c > index 20e3f87..797c7d0 100644 > --- a/arch/x86/mm/fault.c > +++ b/arch/x86/mm/fault.c > @@ -1035,6 +1035,7 @@ do_page_fault(struct pt_regs *regs, unsigned long error_code) > if (user_mode_vm(regs)) { > local_irq_enable(); > error_code |= PF_USER; > + flags |= FAULT_FLAG_KILLABLE; > } else { > if (regs->flags & X86_EFLAGS_IF) > local_irq_enable(); > @@ -1138,6 +1139,14 @@ good_area: > } > > /* > + * Pagefault was interrupted by SIGKILL. We have no reason to > + * continue pagefault. > + */ > + if ((flags & FAULT_FLAG_KILLABLE) && (fault & VM_FAULT_RETRY) && > + fatal_signal_pending(current)) > + return; > + Hmm? up_read(&mm->mmap_sem) ? Thanks, -Kame -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org