From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with SMTP id 424EF6B0098 for ; Tue, 16 Nov 2010 23:19:35 -0500 (EST) Date: Wed, 17 Nov 2010 12:19:26 +0800 From: Wu Fengguang Subject: Re: [PATCH 01/13] writeback: IO-less balance_dirty_pages() Message-ID: <20101117041926.GA14209@localhost> References: <20101117035905.525232375@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20101117035905.525232375@intel.com> Sender: owner-linux-mm@kvack.org To: Andrew Morton Cc: Theodore Ts'o , Chris Mason , Dave Chinner , Jan Kara , Peter Zijlstra , Jens Axboe , Mel Gorman , Rik van Riel , KOSAKI Motohiro , Christoph Hellwig , linux-mm , "linux-fsdevel@vger.kernel.org" , LKML List-ID: > BEHAVIOR CHANGE > =============== > > Users will notice that the applications will get throttled once the > crossing the global (background + dirty)/2=15% threshold. For a single > "cp", it could be soft throttled at 2*bdi->write_bandwidth around 15% s/2/8/ Sorry, the initial soft throttle bandwidth for "cp" is about 8 times of bdi bandwidth when reaching 15% dirty pages. > dirty pages, and be balanced at speed bdi->write_bandwidth around 17.5% > dirty pages. Before patch, the behavior is to just throttle it at 17.5% > dirty pages. > > Since the task will be soft throttled earlier than before, it may be > perceived by end users as performance "slow down" if his application > happens to dirty more than ~15% memory. -- 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