From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751916AbaI3Ot5 (ORCPT ); Tue, 30 Sep 2014 10:49:57 -0400 Received: from mga02.intel.com ([134.134.136.20]:44054 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750809AbaI3Oty (ORCPT ); Tue, 30 Sep 2014 10:49:54 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,626,1406617200"; d="scan'208";a="610929837" Date: Tue, 30 Sep 2014 10:48:54 -0400 From: Matthew Wilcox To: Valdis.Kletnieks@vt.edu Cc: Matthew Wilcox , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Matthew Wilcox Subject: Re: [PATCH v11 00/21] Add support for NV-DIMMs to ext4 Message-ID: <20140930144854.GA5098@wil.cx> References: <1411677218-29146-1-git-send-email-matthew.r.wilcox@intel.com> <15705.1412070301@turing-police.cc.vt.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <15705.1412070301@turing-police.cc.vt.edu> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 30, 2014 at 05:45:01AM -0400, Valdis.Kletnieks@vt.edu wrote: > On Thu, 25 Sep 2014 16:33:17 -0400, Matthew Wilcox said: > > > Patch 19 adds some DAX infrastructure to support ext4. > > > > Patch 20 adds DAX support to ext4. It is broadly similar to ext2's DAX > > support, but it is more efficient than ext4's due to its support for > > unwritten extents. > > I don't currently have a use case for NV-DIMM support. > > However, it would be nice if this code could be leveraged to support > 'force O_DIRECT on all I/O to this file' - that I *do* have a use > case for. Patch 20 looks to my untrained eye like it *almost* gets > there. > > (And if in fact it *does* do the whole enchilada, the Changelog etc should > mention it :) No, it doesn't try to do that. Wouldn't you be better served with an LD_PRELOAD that forces O_DIRECT on?