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 SMTP id 437366B022B for ; Tue, 15 Jun 2010 09:32:55 -0400 (EDT) Message-ID: <4C1780F2.7010003@redhat.com> Date: Tue, 15 Jun 2010 09:32:34 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH 11/12] vmscan: Write out dirty pages in batch References: <1276514273-27693-1-git-send-email-mel@csn.ul.ie> <1276514273-27693-12-git-send-email-mel@csn.ul.ie> <20100614231144.GG6590@dastard> <20100614162143.04783749.akpm@linux-foundation.org> <20100615003943.GK6590@dastard> <4C16D46D.3020302@redhat.com> <20100615110102.GD31051@infradead.org> In-Reply-To: <20100615110102.GD31051@infradead.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Christoph Hellwig Cc: Dave Chinner , Andrew Morton , Mel Gorman , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Chris Mason , Nick Piggin , Johannes Weiner , KAMEZAWA Hiroyuki List-ID: On 06/15/2010 07:01 AM, Christoph Hellwig wrote: > On Mon, Jun 14, 2010 at 09:16:29PM -0400, Rik van Riel wrote: >>> Besides, there really isn't the right context in the block layer to >>> be able to queue and prioritise large amounts of IO without >>> significant penalties to some higher layer operation. >> >> Can we kick flushing for the whole inode at once from >> vmscan.c? > > kswapd really should be a last effort tool to clean filesystem pages. > If it does enough I/O for this to matter significantly we need to > fix the VM to move more work to the flusher threads instead of trying > to fix kswapd. > >> Would it be hard to add a "please flush this file" >> way to call the filesystem flushing threads? > > We already have that API, in Jens' latest tree that's > sync_inodes_sb/writeback_inodes_sb. We could also add a non-waiting > variant if required, but I think the big problem with kswapd is that > we want to wait on I/O completion under circumstances. However, kswapd does not need to wait on I/O completion of any page in particular - it just wants to wait on I/O completion of any inactive pages in the zone (or memcg) where memory is being freed. -- All rights reversed -- 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