From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from rcsinet15.oracle.com ([148.87.113.117]:30489 "EHLO rcsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757760Ab2JaAfE (ORCPT ); Tue, 30 Oct 2012 20:35:04 -0400 Message-ID: <5090721E.2090806@oracle.com> Date: Wed, 31 Oct 2012 08:34:38 +0800 From: Liu Bo MIME-Version: 1.0 To: David Sterba CC: linux-btrfs@vger.kernel.org Subject: Re: [PATCH 2/2] Btrfs: make snapshot-aware defrag as a mount option References: <1351333721-3220-1-git-send-email-bo.li.liu@oracle.com> <1351333721-3220-2-git-send-email-bo.li.liu@oracle.com> <20121030233146.GB3102@twin.jikos.cz> In-Reply-To: <20121030233146.GB3102@twin.jikos.cz> Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 10/31/2012 07:31 AM, David Sterba wrote: > On Sat, Oct 27, 2012 at 06:28:41PM +0800, Liu Bo wrote: >> This feature works on our crucial write endio path, so if we've got >> lots of fragments to process, it will be kind of a disaster to the >> performance, so I make such a change. >> >> One can benifit from it while mounting with '-o snap_aware_defrag'. > > I vote for a more fine grained control over this feature, ie. via > 'btrfs fi defrag', off by default (current behaviour). The defrag ioctl > is the only place that actually calls set_extent_defrag, so this will > not affect normal operation and is fully in hands of the user who runs > defrag. > Besides 'btrfs fi defrag', mounting with autodefrag may also do the same thing. But controlling by 'btrfs fi defrag' can actually be a good idea. thanks, liubo > Do you have a usecase for setting it through the mount option? > > thanks, > david > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >