From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dkim1.fusionio.com ([66.114.96.53]:43575 "EHLO dkim1.fusionio.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750939Ab3CNSib (ORCPT ); Thu, 14 Mar 2013 14:38:31 -0400 Received: from mx2.fusionio.com (unknown [10.101.1.160]) by dkim1.fusionio.com (Postfix) with ESMTP id 7E52B7C0446 for ; Thu, 14 Mar 2013 12:38:31 -0600 (MDT) Date: Thu, 14 Mar 2013 14:38:29 -0400 From: Chris Mason To: Liu Bo CC: "dsterba@suse.cz" , "linux-btrfs@vger.kernel.org" Subject: Re: [PATCH] Btrfs: get better concurrency for snapshot-aware defrag work Message-ID: <20130314183829.GC18457@shiny.masoncoding.com> References: <1362993658-30147-1-git-send-email-bo.li.liu@oracle.com> <20130311172640.GF7229@twin.jikos.cz> <20130312014402.GC31527@liubo.jp.oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" In-Reply-To: <20130312014402.GC31527@liubo.jp.oracle.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Mon, Mar 11, 2013 at 07:44:04PM -0600, Liu Bo wrote: > On Mon, Mar 11, 2013 at 06:26:40PM +0100, David Sterba wrote: > > On Mon, Mar 11, 2013 at 05:20:58PM +0800, Liu Bo wrote: > > > Using spinning case instead of blocking will result in better concurrency > > > overall. > > > > Do you have numbers to support that? > > > > Sorry, I don't, just judging from what leave_spinning is desiged for and the > similar usecases, like insert_reserved_file_extents(), which is also involved in > endio write worker. Leaving the path spinning is always faster. As long as you're sure the code inside doesn't schedule it is the right choice. -chris