From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with SMTP id 3223C6B004D for ; Tue, 17 Nov 2009 17:11:46 -0500 (EST) Date: Wed, 18 Nov 2009 09:11:08 +1100 From: Dave Chinner Subject: Re: [PATCH 7/7] xfs: Don't use PF_MEMALLOC Message-ID: <20091117221108.GK9467@discord.disaster> References: <20091117161551.3DD4.A69D9226@jp.fujitsu.com> <20091117162235.3DEB.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20091117162235.3DEB.A69D9226@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: 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. Cheers, Dave. -- Dave Chinner david@fromorbit.com -- 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