Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C2767C169C4 for ; Fri, 8 Feb 2019 09:02:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9A6DA21916 for ; Fri, 8 Feb 2019 09:02:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727384AbfBHJCs (ORCPT ); Fri, 8 Feb 2019 04:02:48 -0500 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 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 83E2BAE30; Fri, 8 Feb 2019 09:02:46 +0000 (UTC) Date: Fri, 8 Feb 2019 10:02:45 +0100 From: Johannes Thumshirn 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" 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: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.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 N?rnberg GF: Felix Imend?rffer, Jane Smithard, Graham Norton HRB 21284 (AG N?rnberg) Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850