Return-Path: Received: from userp1040.oracle.com ([156.151.31.81]:26129 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753172AbcFOQkD (ORCPT ); Wed, 15 Jun 2016 12:40:03 -0400 Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) Subject: Re: [PATCH v2 01/24] mlx4-ib: Use coherent memory for priv pages From: Chuck Lever In-Reply-To: <20160615042849.GR5408@leon.nu> Date: Wed, 15 Jun 2016 12:40:07 -0400 Cc: linux-rdma@vger.kernel.org, Linux NFS Mailing List Message-Id: <68F7CD80-0092-4B55-9FAD-4C54D284BCA3@oracle.com> References: <20160615030626.14794.43805.stgit@manet.1015granger.net> <20160615031525.14794.69066.stgit@manet.1015granger.net> <20160615042849.GR5408@leon.nu> To: leon@kernel.org Sender: linux-nfs-owner@vger.kernel.org List-ID: > On Jun 15, 2016, at 12:28 AM, Leon Romanovsky wrote: > > On Tue, Jun 14, 2016 at 11:15:25PM -0400, Chuck Lever wrote: >> From: Sagi Grimberg >> >> kmalloc doesn't guarantee the returned memory is all on one page. > > IMHO, the patch posted by Christoph at that thread is best way to go, > because you changed streaming DMA mappings to be coherent DMA mappings [1]. > > "The kernel developers recommend the use of streaming mappings over > coherent mappings whenever possible" [1]. > > [1] http://www.makelinux.net/ldd3/chp-15-sect-4 Hi Leon- I'll happily drop this patch from my 4.8 series as soon as an official mlx4/mlx5 fix is merged. Meanwhile, I notice some unexplained instability (driver resets, list corruption, and so on) when I test NFS/RDMA without this patch included. So it is attached to the series for anyone with mlx4 who wants to pull my topic branch and try it out. -- Chuck Lever