From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754456Ab1FSPgk (ORCPT ); Sun, 19 Jun 2011 11:36:40 -0400 Received: from 173-166-109-252-newengland.hfc.comcastbusiness.net ([173.166.109.252]:39310 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754249Ab1FSPgi (ORCPT ); Sun, 19 Jun 2011 11:36:38 -0400 Date: Sun, 19 Jun 2011 11:36:37 -0400 From: Christoph Hellwig To: Wu Fengguang Cc: "linux-fsdevel@vger.kernel.org" , Jan Kara , Dave Chinner , Christoph Hellwig , Andrew Morton , LKML Subject: Re: [PATCH 3/7] writeback: introduce smoothed global dirty limit Message-ID: <20110619153636.GC20424@infradead.org> References: <20110619150108.691351746@intel.com> <20110619150510.246140117@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110619150510.246140117@intel.com> User-Agent: Mutt/1.5.21 (2010-09-15) 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 Sun, Jun 19, 2011 at 11:01:11PM +0800, Wu Fengguang wrote: > The start of a heavy weight application (ie. KVM) may instantly knock > down determine_dirtyable_memory() and hence the global/bdi dirty > thresholds. > > So introduce global_dirty_limit for tracking the global dirty threshold > with policies > > - follow downwards slowly > - follow up in one shot > > global_dirty_limit can effectively mask out the impact of sudden drop of > dirtyable memory. It will be used in the next patch for two new type of > dirty limits. This needs to be explained in more detail in comments near the actual code.