From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Wilcox Subject: Aggregating discard requests in the filesystem Date: Mon, 10 Nov 2008 13:39:15 -0700 Message-ID: <20081110203915.GP15439@parisc-linux.org> References: <4913028B.6010405@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: David Woodhouse , James Bottomley , linux-scsi@vger.kernel.org, linux-fsdevel@vger.kernel.org, Black_David@emc.com, "Martin K. Petersen" , Tom Coughlan , Jens Axboe , Chris Mason , Dave Chinner To: Ric Wheeler Return-path: Received: from palinux.external.hp.com ([192.25.206.14]:40875 "EHLO mail.parisc-linux.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752858AbYKJUjR (ORCPT ); Mon, 10 Nov 2008 15:39:17 -0500 Content-Disposition: inline In-Reply-To: <4913028B.6010405@redhat.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Thu, Nov 06, 2008 at 09:43:23AM -0500, Ric Wheeler wrote: > I have been thinking about whether or not we can (and should) do > anything more than our current best effort to send down large chunks > (note that the "chunk" size can range from reasonable sizes like 8KB or > so up to close to 1MB!). One of the proposals in this thread (that has got buried somewhere) was to expand any discard request sent down from the filesystem to encompass all the adjacent free space. I've checked with our SSD people and they're fine with this idea. dwmw2 says "it isn't actually that hard in FAT" and then interjects some personal opinion about this solution ;-) Is it hard in XFS? btrfs? ext2? Does anyone have a problem with this as a solution? -- Matthew Wilcox Intel Open Source Technology Centre "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step."