From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761884Ab3DBJyD (ORCPT ); Tue, 2 Apr 2013 05:54:03 -0400 Received: from 173-166-109-252-newengland.hfc.comcastbusiness.net ([173.166.109.252]:40161 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759586Ab3DBJyA (ORCPT ); Tue, 2 Apr 2013 05:54:00 -0400 Date: Tue, 2 Apr 2013 11:53:53 +0200 From: Jens Axboe To: Tejun Heo Cc: linux-kernel@vger.kernel.org, Jan Kara , Fengguang Wu , Jeff Moyer Subject: Re: [GIT PULL] writeback: convert writeback to unbound workqueue Message-ID: <20130402095353.GB4667@kernel.dk> References: <20130402030933.GB6255@htj.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130402030933.GB6255@htj.dyndns.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 01 2013, Tejun Heo wrote: > Hello, Jens. > > This is the pull request for the earlier patchset[1] with the same > name. It's only three patches (the first one was committed to > workqueue tree) but the merge strategy is a bit involved due to the > dependencies. > > * Because the conversion needs features from wq/for-3.10, > block/for-3.10/core is based on rc3, and wq/for-3.10 has conflicts > with rc3, I pulled mainline (rc5) into wq/for-3.10 to prevent those > workqueue conflicts from flaring up in block tree. > > * Resolving the issue that Jan and Dave raised about debugging > requires arch-wide changes. The patchset is being worked on[2] but > it'll have to go through -mm after these changes show up in -next, > and not included in this pull request. > > The three commits are located in the following git branch. > > git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git writeback-workqueue > > Pulling it into block/for-3.10/core produces a conflict in > drivers/md/raid5.c between the following two commits. > > e3620a3ad5 ("MD RAID5: Avoid accessing gendisk or queue structs when not available") > 2f6db2a707 ("raid5: use bio_reset()") > > The conflict is trivial - one removes an "if ()" conditional while the > other removes "rbi->bi_next = NULL" right above it. We just need to > remove both. The merged branch is available at > > git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git block-test-merge > > so that you can use it for verification. The test merge commit has > proper merge description. > > While these changes are a bit of pain to route, they make code simpler > and even have, while minute, measureable performance gain[3] even on a > workload which isn't particularly favorable to showing the benefits of > this conversion. Thanks, pulled in for testing. We'll need the debug change in before sending this upstream, though. I agree with Jan/Dave that this is required functionality, for debugging purposes. -- Jens Axboe