Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030608AbbD1Rbn (ORCPT ); Tue, 28 Apr 2015 13:31:43 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34306 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030304AbbD1Rbl (ORCPT ); Tue, 28 Apr 2015 13:31:41 -0400 Date: Tue, 28 Apr 2015 18:31:37 +0100 From: Alasdair G Kergon To: Ming Lin Cc: linux-kernel@vger.kernel.org, Christoph Hellwig , Jens Axboe , Kent Overstreet , Dongsu Park , Lars Ellenberg , drbd-user@lists.linbit.com, Jiri Kosina , Yehuda Sadeh , Sage Weil , Alex Elder , ceph-devel@vger.kernel.org, Alasdair Kergon , Mike Snitzer , dm-devel@redhat.com, Neil Brown , linux-raid@vger.kernel.org, Christoph Hellwig , "Martin K. Petersen" , Dave Chinner Subject: Re: [PATCH 07/10] block: kill merge_bvec_fn() completely Message-ID: <20150428173137.GC12975@agk-dp.fab.redhat.com> Mail-Followup-To: Ming Lin , linux-kernel@vger.kernel.org, Christoph Hellwig , Jens Axboe , Kent Overstreet , Dongsu Park , Lars Ellenberg , drbd-user@lists.linbit.com, Jiri Kosina , Yehuda Sadeh , Sage Weil , Alex Elder , ceph-devel@vger.kernel.org, Alasdair Kergon , Mike Snitzer , dm-devel@redhat.com, Neil Brown , linux-raid@vger.kernel.org, Christoph Hellwig , "Martin K. Petersen" , Dave Chinner References: <1430203717-13307-1-git-send-email-mlin@kernel.org> <1430203717-13307-8-git-send-email-mlin@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1430203717-13307-8-git-send-email-mlin@kernel.org> Organization: Red Hat UK Ltd. Registered in England and Wales, number 03798903. Registered Office: 64 Baker Street, 4th floor, London, W1U 7DF. User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 836 Lines: 19 On Mon, Apr 27, 2015 at 11:48:34PM -0700, Ming Lin wrote: > As generic_make_request() is now able to handle arbitrarily sized bios, > it's no longer necessary for each individual block driver to define its > own ->merge_bvec_fn() callback. Remove every invocation completely. merge_bvec_fn is also about telling the code building up bios what optimum maximum size to use. Have you got some test data to demonstrate that we won't find some situations where performance is now lost by code building up bios that are far too big and are always going to have to be split up later? Alasdair -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/