From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with SMTP id 209356B0071 for ; Wed, 24 Nov 2010 08:46:47 -0500 (EST) Date: Wed, 24 Nov 2010 21:46:41 +0800 From: Wu Fengguang Subject: Re: [PATCH 06/13] writeback: bdi write bandwidth estimation Message-ID: <20101124134641.GA12987@localhost> References: <20101117042720.033773013@intel.com> <20101117042850.002299964@intel.com> <1290596732.2072.450.camel@laptop> <20101124121046.GA8333@localhost> <1290603047.2072.465.camel@laptop> <20101124131437.GE10413@localhost> <20101124132012.GA12117@localhost> <1290606129.2072.467.camel@laptop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1290606129.2072.467.camel@laptop> Sender: owner-linux-mm@kvack.org To: Peter Zijlstra Cc: Andrew Morton , Jan Kara , "Li, Shaohua" , Christoph Hellwig , Dave Chinner , Theodore Ts'o , Chris Mason , Mel Gorman , Rik van Riel , KOSAKI Motohiro , linux-mm , "linux-fsdevel@vger.kernel.org" , LKML List-ID: On Wed, Nov 24, 2010 at 09:42:09PM +0800, Peter Zijlstra wrote: > On Wed, 2010-11-24 at 21:20 +0800, Wu Fengguang wrote: > > > (jiffies - bdi->write_bandwidth_update_time < elapsed) > > > > this will be true if someone else has _done_ overlapped estimation, > > otherwise it will equal: > > > > jiffies - bdi->write_bandwidth_update_time == elapsed > > > > Sorry the comment needs updating. > > Right, but its racy as hell.. Yeah, for N concurrent dirtiers, plus the background flusher, only one is able to update write_bandwidth[_update_time].. -- 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/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org