Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758136Ab1F1Npw (ORCPT ); Tue, 28 Jun 2011 09:45:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53668 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756592Ab1F1NpD (ORCPT ); Tue, 28 Jun 2011 09:45:03 -0400 Date: Tue, 28 Jun 2011 09:45:00 -0400 From: Vivek Goyal To: Konstantin Khlebnikov Cc: "linux-kernel@vger.kernel.org" , "jaxboe@fusionio.com" , "linux-fsdevel@vger.kernel.org" , "linux-ext4@vger.kernel.org" , "jmoyer@redhat.com" Subject: Re: [RFC PATCH 0/3] block: Fix fsync slowness with CFQ cgroups Message-ID: <20110628134500.GD17552@redhat.com> References: <1309205864-13124-1-git-send-email-vgoyal@redhat.com> <4E09B457.9050800@parallels.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4E09B457.9050800@parallels.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1858 Lines: 45 On Tue, Jun 28, 2011 at 03:00:39PM +0400, Konstantin Khlebnikov wrote: > Vivek Goyal wrote: > >This patch series seems to be working for me. I did testing for ext4 only. > >This series is based on for-3.1/core branch of Jen's block tree. > >Konstantin, can you please give it a try and see if it fixes your > >issue. > > It works for me too, for ext3 and ext4, on top 3.0-rc5, after these trivial fixes: > > --- a/block/cfq-iosched.c > +++ b/block/cfq-iosched.c > @@ -1511,7 +1519,7 @@ static void cfq_add_rq_rb(struct request *rq) > * if that happens, put the alias on the dispatch list > */ > while ((__alias = elv_rb_add(&cfqq->sort_list, rq)) != NULL) > - cfq_dispatch_insert(cfqd->queue, __alias); > + cfq_dispatch_insert(cfqd->queue, __alias, false); > > if (!cfq_cfqq_on_rr(cfqq)) > cfq_add_cfqq_rr(cfqd, cfqq); > @@ -3797,12 +3797,11 @@ cfq_set_depends_on_task(struct request_queue *q, struct task_struct *tsk) > */ > rcu_read_lock(); > if (task_blkio_cgroup(current) == task_blkio_cgroup(tsk)) > - return; > - rcu_read_unlock(); > + goto out_unlock_rcu; > > cic = cfq_cic_lookup(cfqd, current->io_context); > if (!cic) > - return; > + goto out_unlock_rcu; You have done this change because you want to keep cfq_cic_lookup() also in rcu read side critical section? I am assuming that it works even without this. Though keeping it under rcu is probably more correct as cic objects are freed in rcu manner. Thanks Vivek -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/