Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933202AbcDLLOB (ORCPT ); Tue, 12 Apr 2016 07:14:01 -0400 Received: from mail-qg0-f50.google.com ([209.85.192.50]:35397 "EHLO mail-qg0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755999AbcDLLN7 (ORCPT ); Tue, 12 Apr 2016 07:13:59 -0400 Date: Tue, 12 Apr 2016 07:13:57 -0400 From: Tejun Heo To: Howard Cochran Cc: linux-kernel@vger.kernel.org, Jens Axboe , Howard Cochran Subject: Re: [PATCH] writeback: Fix performance regression in wb_over_bg_thresh() Message-ID: <20160412111357.GS24661@htj.duckdns.org> References: <1457590359-5837-1-git-send-email-hcochran@kernelspring.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1457590359-5837-1-git-send-email-hcochran@kernelspring.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 877 Lines: 21 On Thu, Mar 10, 2016 at 01:12:39AM -0500, Howard Cochran wrote: > Commit 947e9762a8dd ("writeback: update wb_over_bg_thresh() to use > wb_domain aware operations") unintentionally changed this function's > meaning from "are there more dirty pages than the background writeback > threshold" to "are there more dirty pages than the writeback threshold". > The background writeback threshold is typically half of the writeback > threshold, so this had the effect of raising the number of dirty pages > required to cause a writeback worker to perform background writeout. ... > Fixes: 947e9762a8dd ("writeback: update wb_over_bg_thresh() to use > wb_domain aware operations") > Signed-off-by: Howard Cochran > Cc: Tejun Heo > Cc: Jens Axboe Acked-by: Tejun Heo Thanks! -- tejun