From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f174.google.com (mail-pf0-f174.google.com [209.85.192.174]) by kanga.kvack.org (Postfix) with ESMTP id BF7106B0005 for ; Mon, 21 Mar 2016 15:25:31 -0400 (EDT) Received: by mail-pf0-f174.google.com with SMTP id x3so276059267pfb.1 for ; Mon, 21 Mar 2016 12:25:31 -0700 (PDT) Received: from bby1mta03.pmc-sierra.bc.ca (bby1mta03.pmc-sierra.com. [216.241.235.118]) by mx.google.com with ESMTPS id w1si3064365par.40.2016.03.21.12.25.30 for (version=TLS1 cipher=AES128-SHA bits=128/128); Mon, 21 Mar 2016 12:25:30 -0700 (PDT) From: Stephen Bates Subject: RE: [PATCH RFC 1/1] Add support for ZONE_DEVICE IO memory with struct pages. Date: Mon, 21 Mar 2016 19:25:29 +0000 Message-ID: <36F6EBABA23FEF4391AF72944D228901EB72CA35@BBYEXM01.pmc-sierra.internal> References: <1457979277-26791-1-git-send-email-stephen.bates@pmcs.com> <20160314212344.GC23727@linux.intel.com> <20160314215708.GA7282@obsidianresearch.com> <56EACAB3.5070301@mellanox.com> <20160317161121.GA19501@obsidianresearch.com> In-Reply-To: <20160317161121.GA19501@obsidianresearch.com> Content-Language: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: Jason Gunthorpe , Haggai Eran Cc: Matthew Wilcox , "linux-mm@kvack.org" , "linux-rdma@vger.kernel.org" , "linux-nvdimm@ml01.01.org" , "javier@cnexlabs.com" , "sagig@mellanox.com" , "leonro@mellanox.com" , "artemyko@mellanox.com" , "hch@infradead.org" >=20 > There are fringe cases that are more complex, and maybe the correct readi= ng > of the spec is to setup routing to avoid optimal paths, but it certainly = is > possible to configure switches in a way that could not guarentee global > ordering. >=20 > Jason If someone configures a multipath PCIe topology I think they will have pote= ntial for out of order RDMA reads/writes regardless of whether the target M= R is in system memory of PCIe memory. So I don't think these crazy topologi= es are uniquely problematic for IOPMEM. Stephen -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org