From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:39254 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726115AbfBHJCs (ORCPT ); Fri, 8 Feb 2019 04:02:48 -0500 Date: Fri, 8 Feb 2019 10:02:45 +0100 From: Johannes Thumshirn Subject: Re: [LSF/MM TOPIC] The end of the DAX experiment Message-ID: <20190208090245.GA8038@linux-x5ow.site> References: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: "Kani, Toshi" Cc: "dan.j.williams@intel.com" , "lsf-pc@lists.linux-foundation.org" , "linux-xfs@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "linux-ext4@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-nvdimm@lists.01.org" On 07/02/2019 22:51, Kani, Toshi wrote: > I've also had multiple users complained about 'mount -o dax' succeeded > by falling back to non-dax despite of their intent. Such users wasted > many hours without knowing their setup error / current restrictions. > The next think they always ask is how to check if dax is enabled in such > case, and they are not happy about limited interfaces (ex. look for > mount entry in /proc/mounts), either. Exactly, there's a need for admins and user-space applications to check if they can use DAX or not. See also [1] for reference. > Same as above. Such enhancement should be possible after EXPERIMENTAL > is removed from 'mount -o dax'. IOW, a separate EXPERIMENTAL message > can be shown when user requests per-directory dax. Just as a data point here, in our Kernels we've removed the EXPERIMENTAL warning for DAX on XFS (but not EXT4) and we are supporting it for some limited use-cases. [1] https://lore.kernel.org/linux-fsdevel/20181002100531.GC4135@quack2.suse.cz/ Byte, Johannes -- Johannes Thumshirn SUSE Labs Filesystems jthumshirn@suse.de +49 911 74053 689 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: Felix Imendörffer, Jane Smithard, Graham Norton HRB 21284 (AG Nürnberg) Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850