Return-Path: Received: from mail-wi0-f173.google.com ([209.85.212.173]:35709 "EHLO mail-wi0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750868AbbGLOmP (ORCPT ); Sun, 12 Jul 2015 10:42:15 -0400 Received: by wiga1 with SMTP id a1so48731626wig.0 for ; Sun, 12 Jul 2015 07:42:13 -0700 (PDT) Subject: Re: [PATCH v1 06/12] xprtrdma: Always provide a write list when sending NFS READ To: Chuck Lever , linux-rdma@vger.kernel.org, linux-nfs@vger.kernel.org References: <20150709203242.26247.4848.stgit@manet.1015granger.net> <20150709204237.26247.297.stgit@manet.1015granger.net> From: Sagi Grimberg Message-ID: <55A27CC3.9080601@dev.mellanox.co.il> Date: Sun, 12 Jul 2015 17:42:11 +0300 MIME-Version: 1.0 In-Reply-To: <20150709204237.26247.297.stgit@manet.1015granger.net> Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-nfs-owner@vger.kernel.org List-ID: On 7/9/2015 11:42 PM, Chuck Lever wrote: > The client has been setting up a reply chunk for NFS READs that are > smaller than the inline threshold. This is not efficient: both the > server and client CPUs have to copy the reply's data payload into > and out of the memory region that is then transferred via RDMA. > > Using the write list, the data payload is moved by the device and no > extra data copying is necessary. > > Signed-off-by: Chuck Lever Reviewed-By: Sagi Grimberg