From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with ESMTP id 1A9416B004D for ; Tue, 17 Nov 2009 07:47:17 -0500 (EST) Date: Tue, 17 Nov 2009 07:47:15 -0500 From: Christoph Hellwig Subject: Re: [PATCH 0/7] Kill PF_MEMALLOC abuse Message-ID: <20091117124715.GA22834@infradead.org> References: <20091117192232.3DF9.A69D9226@jp.fujitsu.com> <20091117102701.GA16472@infradead.org> <20091117212327.3E08.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20091117212327.3E08.A69D9226@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: Christoph Hellwig , linux-mm , LKML , Andrew Morton List-ID: On Tue, Nov 17, 2009 at 09:24:24PM +0900, KOSAKI Motohiro wrote: > > On Tue, Nov 17, 2009 at 07:24:42PM +0900, KOSAKI Motohiro wrote: > > > if xfsbufd doesn't only write out dirty data but also drop page, > > > I agree you. > > > > It then drops the reference to the buffer which drops references to the > > pages, which often are the last references, yes. > > I though it is not typical case. Am I wrong? > if so, I'm sorry. I'm not XFS expert. I think in the typical case it's the last reference. The are two reasons why it might not be: - we're on a filesystem with block size < page size in which case two buffers can share a page and we'd need to write out and release both buffers to free the page - someone else might have a reference on the buffer. Offhand I can't remember a place where we do this for delayed write buffers (which is what xfsbufd writes out) as it would be a bit against the purpose of those delayed write buffers. -- 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