From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 81CF6C43441 for ; Wed, 21 Nov 2018 04:42:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 541C72145D for ; Wed, 21 Nov 2018 04:42:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 541C72145D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=grimberg.me Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727029AbeKUPOz (ORCPT ); Wed, 21 Nov 2018 10:14:55 -0500 Received: from mail-pl1-f194.google.com ([209.85.214.194]:46812 "EHLO mail-pl1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725939AbeKUPOz (ORCPT ); Wed, 21 Nov 2018 10:14:55 -0500 Received: by mail-pl1-f194.google.com with SMTP id t13so3573825ply.13; Tue, 20 Nov 2018 20:42:07 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:from:to:cc:references:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=beNzxtekC3eXWHufu9KYAAFX95VFF++NlzuARk/OlmM=; b=OtGo04Uq2QpF0OwfLkHXvcJkd6Qgo4FtDHwcw1PLV7ZutmqvcCH9n05BcvPbN9epud AvrARewg1IxOuuZTbEv9Ff+I4p2oKJrQFirTu4nNJjN62JARofS2egUQjF6gf4NtlgZg hOgNGZjV/GNFEjVlNOb0eNQAIBmETBl0UtZPT96Pg/HiUNFaflL6X228M/ljpjBrH++R EYnvlnf/oYyEUDr1mSdmlq86GoCwqRJB/whBF2jdYjpPkC4I3OQwOD/QDlzZ7x1YKVmW ViWCVfp/oq+uz8+m4hxO8G+QSWOQ4QjBZtqcFQsJxckJZTaAhZFumjnq8/y6nx/dZtFV K0zQ== X-Gm-Message-State: AA+aEWY/NG424koZUjf0EADULCbDS5H/+YCOrrB9fSb+KASvNWPdknGE nv/U3XdrSFC+YYo+38hmtB0= X-Google-Smtp-Source: AFSGD/VfQU9yeCQvEyKVSqmkBBv3/CBEFUNv2FLAgZo9cuQAsWuO+IksYjy7sC2dMkjEksRN1uHK8Q== X-Received: by 2002:a63:f006:: with SMTP id k6mr4563792pgh.259.1542775327338; Tue, 20 Nov 2018 20:42:07 -0800 (PST) Received: from ?IPv6:2601:647:4800:973f:8a0:7611:3223:f4db? ([2601:647:4800:973f:8a0:7611:3223:f4db]) by smtp.gmail.com with ESMTPSA id v20-v6sm49421268pfm.114.2018.11.20.20.42.05 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 20 Nov 2018 20:42:06 -0800 (PST) Subject: Re: [PATCH V10 09/19] block: introduce bio_bvecs() From: Sagi Grimberg To: Ming Lei Cc: Christoph Hellwig , Jens Axboe , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Dave Chinner , Kent Overstreet , Mike Snitzer , dm-devel@redhat.com, Alexander Viro , linux-fsdevel@vger.kernel.org, Shaohua Li , linux-raid@vger.kernel.org, linux-erofs@lists.ozlabs.org, David Sterba , linux-btrfs@vger.kernel.org, "Darrick J . Wong" , linux-xfs@vger.kernel.org, Gao Xiang , Theodore Ts'o , linux-ext4@vger.kernel.org, Coly Li , linux-bcache@vger.kernel.org, Boaz Harrosh , Bob Peterson , cluster-devel@redhat.com References: <20181115085306.9910-1-ming.lei@redhat.com> <20181115085306.9910-10-ming.lei@redhat.com> <20181116134541.GH3165@lst.de> <002fe56b-25e4-573e-c09b-bb12c3e8d25a@grimberg.me> <20181120161651.GB2629@lst.de> <53526aae-fb9b-ee38-0a01-e5899e2d4e4d@grimberg.me> <20181121005902.GA31748@ming.t460p> <2d9bee7a-f010-dcf4-1184-094101058584@grimberg.me> <20181121034415.GA8408@ming.t460p> <2a47d336-c19b-6bf4-c247-d7382871eeea@grimberg.me> Message-ID: <7378bf49-5a7e-5622-d4d1-808ba37ce656@grimberg.me> Date: Tue, 20 Nov 2018 20:42:04 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <2a47d336-c19b-6bf4-c247-d7382871eeea@grimberg.me> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >> Yeah, that is the most common example, given merge is enabled >> in most of cases. If the driver or device doesn't care merge, >> you can disable it and always get single bio request, then the >> bio's bvec table can be reused for send(). > > Does bvec_iter span bvecs with your patches? I didn't see that change? Wait, I see that the bvec is still a single array per bio. When you said a table I thought you meant a 2-dimentional array... Unless I'm not mistaken, I think that the change is pretty simple then. However, nvme-tcp still needs to be bio aware unless we have some abstraction in place.. Which will mean that nvme-tcp will need to open-code bio_bvecs.