Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932189AbdI0PzE (ORCPT ); Wed, 27 Sep 2017 11:55:04 -0400 Received: from mail-oi0-f46.google.com ([209.85.218.46]:52852 "EHLO mail-oi0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752877AbdI0PzB (ORCPT ); Wed, 27 Sep 2017 11:55:01 -0400 X-Google-Smtp-Source: AOwi7QBp0BNRQMUKDEcAZ0RVo90heq6+jwFPA7oDoaTcXcgIT8uV/eh+XDb3qqeep2EUyDQLJG5XdhynaPQwJQJyLrg= MIME-Version: 1.0 In-Reply-To: <20170927153918.GA24314@linux.intel.com> References: <20170925231404.32723-1-ross.zwisler@linux.intel.com> <20170925231404.32723-7-ross.zwisler@linux.intel.com> <20170926185751.GB31146@linux.intel.com> <20170926210645.GA7798@linux.intel.com> <20170927113527.GD25746@quack2.suse.cz> <20170927153918.GA24314@linux.intel.com> From: Dan Williams Date: Wed, 27 Sep 2017 08:54:59 -0700 Message-ID: Subject: Re: [PATCH 6/7] mm, fs: introduce file_operations->post_mmap() To: Ross Zwisler , Jan Kara , Dan Williams , Andrew Morton , "linux-kernel@vger.kernel.org" , "Darrick J. Wong" , "J. Bruce Fields" , Christoph Hellwig , Dave Chinner , Jeff Layton , linux-fsdevel , Linux MM , "linux-nvdimm@lists.01.org" , linux-xfs@vger.kernel.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: 981 Lines: 20 On Wed, Sep 27, 2017 at 8:39 AM, Ross Zwisler wrote: > On Wed, Sep 27, 2017 at 01:35:27PM +0200, Jan Kara wrote: [..] >> Hum, this is an interesting option. So do you suggest that filesystems >> supporting DAX would always setup mappings with VM_MIXEDMAP and without >> VM_HUGEPAGE and thus we'd get rid of dependency on S_DAX flag in ->mmap? >> That could actually work. The only possible issue I can see is that >> VM_MIXEDMAP is still slightly different from normal page mappings and it >> could have some performance implications - e.g. copy_page_range() does more >> work on VM_MIXEDMAP mappings but not on normal page mappings. > > It looks like having VM_MIXEDMAP always set for filesystems that support DAX > might affect their memory's NUMA migration in the non-DAX case? > > 8e76d4e sched, numa: do not hint for NUMA balancing on VM_MIXEDMAP mappings Addressed separately here: c1ef8e2c0235 mm: disable numa migration faults for dax vmas