Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751830AbdGZAPO (ORCPT ); Tue, 25 Jul 2017 20:15:14 -0400 Received: from mail-wm0-f65.google.com ([74.125.82.65]:33436 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751756AbdGZAPM (ORCPT ); Tue, 25 Jul 2017 20:15:12 -0400 MIME-Version: 1.0 In-Reply-To: <1500552639-18523-1-git-send-email-sunqiuyang@huawei.com> References: <1500552639-18523-1-git-send-email-sunqiuyang@huawei.com> From: Dan Williams Date: Tue, 25 Jul 2017 17:15:10 -0700 Message-ID: Subject: Re: [PATCH v8 1/1] f2fs: dax: implement direct access To: sunqiuyang Cc: Linux Kernel Mailing List , linux-fsdevel , linux-f2fs-devel@lists.sourceforge.net, Jaegeuk Kim , "linux-nvdimm@lists.01.org" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 825 Lines: 18 [ adding linux-nvdimm ] On Thu, Jul 20, 2017 at 5:10 AM, sunqiuyang wrote: > From: Qiuyang Sun > > This patch implements Direct Access (DAX) in F2FS, including: > - a mount option to choose whether to enable DAX or not We're in the process of walking back and potentially deprecating the use of the dax mount option for xfs and ext4 since dax can have negative performance implications if page cache memory happens to be faster than pmem. It should be limited to applications that specifically want the semantic, not globally enabled for the entire mount. xfs has went ahead and added the XFS_DIFLAG2_DAX indoe flag for per-inode enabling of dax. I'm wondering if any new filesystem that adds dax support at this point should do so with inode flags and not a mount option?