From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754393AbaIBQYX (ORCPT ); Tue, 2 Sep 2014 12:24:23 -0400 Received: from mail-pa0-f52.google.com ([209.85.220.52]:50629 "EHLO mail-pa0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751821AbaIBQYW (ORCPT ); Tue, 2 Sep 2014 12:24:22 -0400 Message-ID: <5405EF38.60007@kernel.dk> Date: Tue, 02 Sep 2014 10:24:24 -0600 From: Jens Axboe User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.0 MIME-Version: 1.0 To: Christoph Hellwig , Ming Lei CC: linux-kernel@vger.kernel.org, Kick In , Chris J Arges Subject: Re: [PATCH] blk-merge: fix blk_recount_segments References: <1409670180-17352-1-git-send-email-ming.lei@canonical.com> <20140902162146.GA28741@infradead.org> In-Reply-To: <20140902162146.GA28741@infradead.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/02/2014 10:21 AM, Christoph Hellwig wrote: > Btw, one thing we should reconsider is where we set > QUEUE_FLAG_NO_SG_MERGE. At least for virtio-blk it seems to me that > doing the S/G merge should be a lot cheaper than fanning out into the > indirect descriptors. And we might consider flipping the default, as most would probably like to have the sg merging on. -- Jens Axboe