Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751604AbdGZRBw (ORCPT ); Wed, 26 Jul 2017 13:01:52 -0400 Received: from bombadil.infradead.org ([65.50.211.133]:53332 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751103AbdGZRBs (ORCPT ); Wed, 26 Jul 2017 13:01:48 -0400 Date: Wed, 26 Jul 2017 10:01:47 -0700 From: Christoph Hellwig To: Dan Williams Cc: Christoph Hellwig , "linux-nvdimm@lists.01.org" , Linux Kernel Mailing List , linux-f2fs-devel@lists.sourceforge.net, linux-fsdevel , Jaegeuk Kim , sunqiuyang Subject: Re: [PATCH v8 1/1] f2fs: dax: implement direct access Message-ID: <20170726170147.GA31930@infradead.org> References: <1500552639-18523-1-git-send-email-sunqiuyang@huawei.com> <20170726072634.GA4684@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.8.0 (2017-02-23) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 611 Lines: 12 On Wed, Jul 26, 2017 at 09:53:07AM -0700, Dan Williams wrote: > It allows for opt-in for applications, or administrators of those > applications, that know the type of access. That's BS. We need to provide the best possible way to access the media to an application. And whether that's DAX or the page cache is an implementation detail that should not matter to the application. Which doesn't mean there shouldn't be ways to override the default that the kernel chose based on hardware details, but it's certainly not something for the application to hardcode, but something for the adminstrator to decide.