Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S947915AbcJaXI3 (ORCPT ); Mon, 31 Oct 2016 19:08:29 -0400 Received: from mail-vk0-f65.google.com ([209.85.213.65]:36248 "EHLO mail-vk0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S947834AbcJaXI0 (ORCPT ); Mon, 31 Oct 2016 19:08:26 -0400 MIME-Version: 1.0 In-Reply-To: <20161031153149.GH30919@infradead.org> References: <1477728600-12938-1-git-send-email-tom.leiming@gmail.com> <1477728600-12938-16-git-send-email-tom.leiming@gmail.com> <20161031153149.GH30919@infradead.org> From: Ming Lei Date: Tue, 1 Nov 2016 07:08:24 +0800 Message-ID: Subject: Re: [PATCH 15/60] block: loop: comment on direct access to bvec table To: Christoph Hellwig Cc: Jens Axboe , Linux Kernel Mailing List , linux-block , Linux FS Devel , "Kirill A . Shutemov" , Hannes Reinecke , Mike Christie , Minfei Huang , Petr Mladek Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 817 Lines: 22 On Mon, Oct 31, 2016 at 11:31 PM, Christoph Hellwig wrote: > Btw, the lib/iov_iter.c code that iterates over bvec currently > expects single-page segments. Is the loop code fine with that? lib/iov_iter.c has switched to bvec iterator already in the mp-bvec preparing patchset, so every thing will be fine after multipage bvec is enabled. Another multipage bvec benefit for lib/iov_iter.c(dio) is that we can return whole pages in one segment, instead of one page each time, such as iov_iter_get_pages(), but that can be a follow-up optimization. > Even if it is I think we'd be much better off if it becomes multipage > segment aware. This patch is for auditing possible effect with multipage bvec, so looks we should expose as much as possible direct access to bvec table. Thanks, Ming Lei