From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755693Ab2GCOBB (ORCPT ); Tue, 3 Jul 2012 10:01:01 -0400 Received: from mx1.redhat.com ([209.132.183.28]:17778 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753430Ab2GCOA7 (ORCPT ); Tue, 3 Jul 2012 10:00:59 -0400 Date: Tue, 3 Jul 2012 10:00:48 -0400 From: Vivek Goyal To: Paolo Bonzini Cc: linux-kernel@vger.kernel.org, axboe@kernel.dk, snitzer@redhat.com, martin.petersen@oracle.com, david@fromorbit.com, xfs@oss.sgi.com, dm-devel@redhat.com, hch@lst.de Subject: Re: [dm-devel] [PATCH v2 1/3] block: add sysfs entry for discard_alignment Message-ID: <20120703140048.GC11272@redhat.com> References: <1341235225-27551-1-git-send-email-pbonzini@redhat.com> <1341235225-27551-2-git-send-email-pbonzini@redhat.com> <20120703023442.GB3586@redhat.com> <4FF2DCB1.2090704@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4FF2DCB1.2090704@redhat.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 On Tue, Jul 03, 2012 at 01:51:13PM +0200, Paolo Bonzini wrote: > Il 03/07/2012 04:34, Vivek Goyal ha scritto: > >> > The next patches will actually use the alignment, expose it in sysfs > >> > for ease of debugging. > >> > > > Don't we already have discard_alignment exported as device attribute. > > > > /sys/block//discard_alignment > > Ah, interesting, I missed it completely. I guess it's because queue/ > directories only exist for full disks, and the correct alignment varies > for each partition. So this patch is unnecessary. Partition discard_alignments are available in /sys/block///discard_alignment. That raises an interesting question for patch3. If the discard is happening to a partition, shouldn't you be looking at partition discard_alignment instead of always looking at queue discard_alignment? Thanks Vivek