From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754863Ab0GGBPp (ORCPT ); Tue, 6 Jul 2010 21:15:45 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:58744 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750795Ab0GGBPk (ORCPT ); Tue, 6 Jul 2010 21:15:40 -0400 Date: Tue, 6 Jul 2010 21:15:33 -0400 From: Christoph Hellwig To: Mel Gorman Cc: Minchan Kim , Johannes Weiner , KOSAKI Motohiro , Andrew Morton , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Dave Chinner , Chris Mason , Nick Piggin , Rik van Riel , Christoph Hellwig , KAMEZAWA Hiroyuki , Andrea Arcangeli Subject: Re: [PATCH 12/14] vmscan: Do not writeback pages in direct reclaim Message-ID: <20100707011533.GB3630@infradead.org> References: <20100702125155.69c02f85.akpm@linux-foundation.org> <20100705134949.GC13780@csn.ul.ie> <20100706093529.CCD1.A69D9226@jp.fujitsu.com> <20100706101235.GE13780@csn.ul.ie> <20100706152539.GG13780@csn.ul.ie> <20100706202758.GC18210@cmpxchg.org> <20100707002458.GI13780@csn.ul.ie> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100707002458.GI13780@csn.ul.ie> User-Agent: Mutt/1.5.20 (2009-08-17) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 07, 2010 at 01:24:58AM +0100, Mel Gorman wrote: > What I have now is direct writeback for anon files. For files be it from > kswapd or direct reclaim, I kick writeback pre-emptively by an amount based > on the dirty pages encountered because monitoring from systemtap indicated > that we were getting a large percentage of the dirty file pages at the end > of the LRU lists (bad). Initial tests show that page reclaim writeback is > reduced from kswapd by 97% with this sort of pre-emptive kicking of flusher > threads based on these figures from sysbench. That sounds like yet another bad aid to me. Instead it would be much better to not have so many file pages at the end of LRU by tuning the flusher threads and VM better. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH 12/14] vmscan: Do not writeback pages in direct reclaim Date: Tue, 6 Jul 2010 21:15:33 -0400 Message-ID: <20100707011533.GB3630@infradead.org> References: <20100702125155.69c02f85.akpm@linux-foundation.org> <20100705134949.GC13780@csn.ul.ie> <20100706093529.CCD1.A69D9226@jp.fujitsu.com> <20100706101235.GE13780@csn.ul.ie> <20100706152539.GG13780@csn.ul.ie> <20100706202758.GC18210@cmpxchg.org> <20100707002458.GI13780@csn.ul.ie> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Minchan Kim , Johannes Weiner , KOSAKI Motohiro , Andrew Morton , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Dave Chinner , Chris Mason , Nick Piggin , Rik van Riel , Christoph Hellwig , KAMEZAWA Hiroyuki , Andrea Arcangeli To: Mel Gorman Return-path: Content-Disposition: inline In-Reply-To: <20100707002458.GI13780@csn.ul.ie> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org On Wed, Jul 07, 2010 at 01:24:58AM +0100, Mel Gorman wrote: > What I have now is direct writeback for anon files. For files be it from > kswapd or direct reclaim, I kick writeback pre-emptively by an amount based > on the dirty pages encountered because monitoring from systemtap indicated > that we were getting a large percentage of the dirty file pages at the end > of the LRU lists (bad). Initial tests show that page reclaim writeback is > reduced from kswapd by 97% with this sort of pre-emptive kicking of flusher > threads based on these figures from sysbench. That sounds like yet another bad aid to me. Instead it would be much better to not have so many file pages at the end of LRU by tuning the flusher threads and VM better. -- 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