From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from verein.lst.de ([213.95.11.211]:45644 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750839AbcKFQgo (ORCPT ); Sun, 6 Nov 2016 11:36:44 -0500 Date: Sun, 6 Nov 2016 17:36:42 +0100 From: Christoph Hellwig Subject: Re: discard improvements Message-ID: <20161106163642.GB15675@lst.de> References: <1476735753-5861-1-git-send-email-hch@lst.de> <64a1c5dc-4a36-1ef6-606e-b382d36161ef@scylladb.com> <20161031151412.GA14804@lst.de> <5a50a07c-369d-1a41-2111-f9ee91ac7425@scylladb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5a50a07c-369d-1a41-2111-f9ee91ac7425@scylladb.com> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Avi Kivity Cc: Christoph Hellwig , linux-xfs@vger.kernel.org, michaelcallahan@fb.com On Sat, Nov 05, 2016 at 08:18:05PM +0200, Avi Kivity wrote: > The big problem with "it depends" is that usually the information it > depends on is not available, so the application has to rely on a human to > guess correctly. With the trend for machines to be managed by machines, > it's really hard to get optimal performance. So exposure of any > information that can help to make a decision, including that the kernel can > make good use of TRIM, will be very helpful. I agree with you, but until devices tell us that their discard implementation sucks on their own there is not much I can help you there.