From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Walker Subject: Re: [PATCH 3/8] writeback: switch to per-bdi threads for flushing data Date: Tue, 08 Sep 2009 06:46:46 -0700 Message-ID: <1252417606.14793.3.camel@desktop> References: <1252401791-22463-1-git-send-email-jens.axboe@oracle.com> <1252401791-22463-4-git-send-email-jens.axboe@oracle.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, chris.mason@oracle.com, david@fromorbit.com, hch@infradead.org, akpm@linux-foundation.org, jack@suse.cz To: Jens Axboe Return-path: Received: from fifo99.com ([67.223.236.141]:45651 "EHLO fifo99.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753800AbZIHNqh (ORCPT ); Tue, 8 Sep 2009 09:46:37 -0400 In-Reply-To: <1252401791-22463-4-git-send-email-jens.axboe@oracle.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Tue, 2009-09-08 at 11:23 +0200, Jens Axboe wrote: > This gets rid of pdflush for bdi writeout and kupdated style cleaning. > pdflush writeout suffers from lack of locality and also requires more > threads to handle the same workload, since it has to work in a > non-blocking fashion against each queue. This also introduces lumpy > behaviour and potential request starvation, since pdflush can be starved > for queue access if others are accessing it. A sample ffsb workload that > does random writes to files is about 8% faster here on a simple SATA drive > during the benchmark phase. File layout also seems a LOT more smooth in > vmstat: This patch has a checkpatch error, and couple of warnings.. Here's one of the warnings which I though was concerning.. WARNING: trailing semicolon indicates no statements, indent implies otherwise #388: FILE: fs/fs-writeback.c:177: + } else if (wb->task); + wake_up_process(wb->task); I suppose that could be a defect .. btw, patch 7 of 8 also has a few trivial warnings. Daniel