From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id 077EA6B004D for ; Wed, 18 Nov 2009 03:56:53 -0500 (EST) Received: from m3.gw.fujitsu.co.jp ([10.0.50.73]) by fgwmail7.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id nAI8upTA030094 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Wed, 18 Nov 2009 17:56:51 +0900 Received: from smail (m3 [127.0.0.1]) by outgoing.m3.gw.fujitsu.co.jp (Postfix) with ESMTP id C889C45DE4F for ; Wed, 18 Nov 2009 17:56:50 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (s3.gw.fujitsu.co.jp [10.0.50.93]) by m3.gw.fujitsu.co.jp (Postfix) with ESMTP id AA36145DE4E for ; Wed, 18 Nov 2009 17:56:50 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id 9666AE08002 for ; Wed, 18 Nov 2009 17:56:50 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.249.87.104]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id 4920AE38003 for ; Wed, 18 Nov 2009 17:56:47 +0900 (JST) From: KOSAKI Motohiro Subject: Re: [PATCH 7/7] xfs: Don't use PF_MEMALLOC In-Reply-To: <20091117221108.GK9467@discord.disaster> References: <20091117162235.3DEB.A69D9226@jp.fujitsu.com> <20091117221108.GK9467@discord.disaster> Message-Id: <20091118153302.3E20.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Date: Wed, 18 Nov 2009 17:56:46 +0900 (JST) Sender: owner-linux-mm@kvack.org To: Dave Chinner Cc: kosaki.motohiro@jp.fujitsu.com, LKML , linux-mm , Andrew Morton , Christoph Hellwig , linux-fsdevel@vger.kernel.org, xfs-masters@oss.sgi.com, xfs@oss.sgi.com List-ID: > On Tue, Nov 17, 2009 at 04:23:43PM +0900, KOSAKI Motohiro wrote: > > > > Non MM subsystem must not use PF_MEMALLOC. Memory reclaim need few > > memory, anyone must not prevent it. Otherwise the system cause > > mysterious hang-up and/or OOM Killer invokation. > > The xfsbufd is a woken run by a registered memory shaker. i.e. it > runs when the system needs to reclaim memory. It forceN? the > delayed write metadata buffers (of which there can be a lot) to disk > so that they can be reclaimed on IO completion. This IO submission > may require N?ome memory to be allocated to be able to free that > memory. > > Hence, AFAICT the use of PF_MEMALLOC is valid here. Thanks a lot. I have one additional question, may I ask you? How can we calculate maximum memory usage in xfsbufd? I'm afraid that VM and XFS works properly but adding two makes memory exhaust. And, I conclude XFS doesn't need sharing reservation memory with VM, it only need non failed allocation. right? IOW I'm prefer perter's suggestion. -- 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