From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay2.corp.sgi.com [137.38.102.29]) by oss.sgi.com (Postfix) with ESMTP id 221FC7CA1 for ; Tue, 27 Sep 2016 14:29:54 -0500 (CDT) Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by relay2.corp.sgi.com (Postfix) with ESMTP id E6B73304048 for ; Tue, 27 Sep 2016 12:29:53 -0700 (PDT) Received: from userp1040.oracle.com (userp1040.oracle.com [156.151.31.81]) by cuda.sgi.com with ESMTP id CrJF1QYQPMg7mhzq (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO) for ; Tue, 27 Sep 2016 12:29:49 -0700 (PDT) Date: Tue, 27 Sep 2016 12:29:19 -0700 From: "Darrick J. Wong" Subject: Re: [PATCH 58/71] xfs: garbage collect old cowextsz reservations Message-ID: <20160927192919.GK14092@birch.djwong.org> References: <147216791538.867.12413509832420924168.stgit@birch.djwong.org> <147216829394.867.16281333542262043955.stgit@birch.djwong.org> <20160924194234.GA1878@infradead.org> <20160926215209.GE14092@birch.djwong.org> <20160927185021.GA8623@infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20160927185021.GA8623@infradead.org> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: Christoph Hellwig Cc: linux-xfs@vger.kernel.org, xfs@oss.sgi.com On Tue, Sep 27, 2016 at 11:50:21AM -0700, Christoph Hellwig wrote: > On Mon, Sep 26, 2016 at 02:52:09PM -0700, Darrick J. Wong wrote: > > The two functions /could/ be merged but I'm hesitant to combine them > > because they run as different workqueue items. > > > > Setting speculative_cow_prealloc_lifetime to a (much) higher value than > > speculative_prealloc_lifetime has been useful for combatting CoW > > fragmentation on VM hosts where the VMs experience bursty write > > behaviors and we can keep the utilization ratios low enough that we > > don't start to run out of space. IOWs, it benefits us to keep the CoW > > fork reservations around for as long as we can unless we run out of > > blocks or hit inode reclaim. > > Ok, so there is a good use case for it. It just felt to me like > there was a little bit too much duplication, that's why I asked. I'll add a brief explanation of this to the patch changelog to record the justification. --D _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs