Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756289Ab0G0Okn (ORCPT ); Tue, 27 Jul 2010 10:40:43 -0400 Received: from gir.skynet.ie ([193.1.99.77]:60991 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754672Ab0G0Okm (ORCPT ); Tue, 27 Jul 2010 10:40:42 -0400 Date: Tue, 27 Jul 2010 15:40:26 +0100 From: Mel Gorman To: Wu Fengguang Cc: "linux-kernel@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "linux-mm@kvack.org" , Dave Chinner , Chris Mason , Nick Piggin , Rik van Riel , Johannes Weiner , Christoph Hellwig , KAMEZAWA Hiroyuki , KOSAKI Motohiro , Andrew Morton , Andrea Arcangeli Subject: Re: [PATCH 8/8] vmscan: Kick flusher threads to clean pages when reclaim is encountering dirty pages Message-ID: <20100727144026.GC5300@csn.ul.ie> References: <1279545090-19169-1-git-send-email-mel@csn.ul.ie> <1279545090-19169-9-git-send-email-mel@csn.ul.ie> <20100726072832.GB13076@localhost> <20100726092616.GG5300@csn.ul.ie> <20100726112709.GB6284@localhost> <20100726125717.GS5300@csn.ul.ie> <20100726131008.GE11947@localhost> <20100727133513.GZ5300@csn.ul.ie> <20100727142412.GA4771@localhost> <20100727143423.GA5057@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20100727143423.GA5057@localhost> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1182 Lines: 26 On Tue, Jul 27, 2010 at 10:34:23PM +0800, Wu Fengguang wrote: > > If you plan to keep wakeup_flusher_threads(), a simpler form may be > > sufficient, eg. > > > > laptop_mode ? 0 : (nr_dirty * 16) > > This number is not sensitive because the writeback code may well round > it up to some more IO efficient value (currently 4MB). AFAIK the > nr_pages parameters passed by all existing flusher callers are some > rule-of-thumb value, and far from being an exact number. > I get that it's a rule of thumb but decided I would still pass in some value related to nr_dirty that was bounded in some manner. Currently, that bound is 4MB but maybe it should have been bound to MAX_WRITEBACK_PAGES (which is 4MB for x86, but could be anything depending on the base page size). -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/