Received: by 2002:a25:4158:0:0:0:0:0 with SMTP id o85csp2704059yba; Mon, 8 Apr 2019 02:55:18 -0700 (PDT) X-Google-Smtp-Source: APXvYqzn+wax6z3WVcuXRX0MU2Z7O4tWJgCaMqyimau1DWIV7ODb4RYZfNy9SVM5ufB8lzjfh406 X-Received: by 2002:a62:26c1:: with SMTP id m184mr29236415pfm.102.1554717318817; Mon, 08 Apr 2019 02:55:18 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1554717318; cv=none; d=google.com; s=arc-20160816; b=bdbarEvYRtM135sdkl1W/a1mcGLPAgOEPfxs0MFuAfxmxRtInQRYfHi+2d2oxjlSgM d1dO6j15GMqIOTV+YikB6JltC/z/EQEgN05RWm4BIq4xwXaZPCv7X1/ll6OiMaksdyw4 p1A7s2xAqnOsoTtlzZu91CAgReVvGHXPGYk9IdhqirvaaTj6DF55njnsunm/U0+8MVSF M9VtxKaETPGa/IhpllXDcEnQU2YubQXz4alWM2OpY1hSVe680B5Uq+d/bLwwqDO2i06B TaxE1/369wc5OaOERu33NVGMHxrOuIudUqquFXp3rA1VpZsgZiSIp/adwoyMj1umox0Q C5kQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding :content-language:in-reply-to:mime-version:user-agent:date :message-id:autocrypt:openpgp:from:references:cc:to:subject; bh=00x+VoKLSDb5b2XVSuYAGbAqgUwnEHj9TwGpC37aJ5g=; b=ueMCZp78s3jnyZQpTTz5NZmOVd8WqW7/nsK0kF8Vz7KbkCUaA8PZJJjGf8MGXhGHxn y6CyVc0bMvWV6t9sJcAQnv9zopPutoAN24D6V8CFgd2a22Safff6+bGbkDa6N+t5npCO 1KFSaDLr82Zg8T1zsIluudrIxZrnaBmj3of9820RnVdGklj37InPrHlPfRmMTFSJraPR kn/j1Y9eaMJcnPh/tsBuGoH9MPbJ5PisRXz1NHB+QeSeazDuzGQ6W2+ku9UGC7qX9Uur BcxRhkDPUSPbr8mk76HeJ801w6NUB6Qk+EJEeL7gDYRjFjpWkBtnaOVhZvIyDGQyScpo OFTg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id n15si26673047pgg.308.2019.04.08.02.55.04; Mon, 08 Apr 2019 02:55:18 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726702AbfDHJxC (ORCPT + 99 others); Mon, 8 Apr 2019 05:53:02 -0400 Received: from mx2.suse.de ([195.135.220.15]:39196 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726666AbfDHJxC (ORCPT ); Mon, 8 Apr 2019 05:53:02 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id D63C3AE31; Mon, 8 Apr 2019 09:52:59 +0000 (UTC) Subject: Re: Possible bio merging breakage in mp bio rework To: Ming Lei , Nikolay Borisov Cc: Jens Axboe , Omar Sandoval , linux-block@vger.kernel.org, LKML , linux-btrfs References: <59c19acf-999f-1911-b0b8-1a5cec8116c5@suse.com> <20190406001653.GA4805@ming.t460p> From: Johannes Thumshirn Openpgp: preference=signencrypt Autocrypt: addr=jthumshirn@suse.de; prefer-encrypt=mutual; keydata= xsFNBFTTwPEBEADOadCyru0ZmVLaBn620Lq6WhXUlVhtvZF5r1JrbYaBROp8ZpiaOc9YpkN3 rXTgBx+UoDGtnz9DZnIa9fwxkcby63igMPFJEYpwt9adN6bA1DiKKBqbaV5ZbDXR1tRrSvCl 2V4IgvgVuO0ZJEt7gakOQlqjQaOvIzDnMIi/abKLSSzYAThsOUf6qBEn2G46r886Mk8MwkJN hilcQ7F5UsKfcVVGrTBoim6j69Ve6EztSXOXjFgsoBw4pEhWuBQCkDWPzxkkQof1WfkLAVJ2 X9McVokrRXeuu3mmB+ltamYcZ/DtvBRy8K6ViAgGyNRWmLTNWdJj19Qgw9Ef+Q9O5rwfbPZy SHS2PVE9dEaciS+EJkFQ3/TBRMP1bGeNbZUgrMwWOvt37yguvrCOglbHW+a8/G+L7vz0hasm OpvD9+kyTOHjqkknVJL69BOJeCIVUtSjT9EXaAOkqw3EyNJzzhdaMXcOPwvTXNkd8rQZIHft SPg47zMp2SJtVdYrA6YgLv7OMMhXhNkUsvhU0HZWUhcXZnj+F9NmDnuccarez9FmLijRUNgL 6iU+oypB/jaBkO6XLLwo2tf7CYmBYMmvXpygyL8/wt+SIciNiM34Yc+WIx4xv5nDVzG1n09b +iXDTYoWH82Dq1xBSVm0gxlNQRUGMmsX1dCbCS2wmWbEJJDEeQARAQABzSdKb2hhbm5lcyBU aHVtc2hpcm4gPGp0aHVtc2hpcm5Ac3VzZS5kZT7CwYAEEwEIACoCGwMFCwkIBwIGFQgJCgsC BBYCAwECHgECF4AFCQo9ta8FAlohZmoCGQEACgkQA5OWnS12CFATLQ//ajhNDVJLK9bjjiOH 53B0+hCrRBj5jQiT8I60+4w+hssvRHWkgsujF+V51jcmX3NOXeSyLC1Gk43A9vCz5gXnqyqG tOlYm26bihzG02eAoWr/glHBQyy7RYcd97SuRSv77WzuXT3mCnM15TKiqXYNzRCK7u5nx4eu szAU+AoXAC/y1gtuDMvANBEuHWE4LNQLkTwJshU1vwoNcTSl+JuQWe89GB8eeeMnHuY92T6A ActzHN14R1SRD/51N9sebAxGVZntXzSVKyMID6eGdNegWrz4q55H56ZrOMQ6IIaa7KSz3QSj 3E8VIY4FawfjCSOuA2joemnXH1a1cJtuqbDPZrO2TUZlNGrO2TRi9e2nIzouShc5EdwmL6qt WG5nbGajkm1wCNb6t4v9ueYMPkHsr6xJorFZHlu7PKqB6YY3hRC8dMcCDSLkOPWf+iZrqtpE odFBlnYNfmAXp+1ynhUvaeH6eSOqCN3jvQbITUo8mMQsdVgVeJwRdeAOFhP7fsxNugii721U acNVDPpEz4QyxfZtfu9QGI405j9MXF/CPrHlNLD5ZM5k9NxnmIdCM9i1ii4nmWvmz9JdVJ+8 6LkxauROr2apgTXxMnJ3Desp+IRWaFvTVhbwfxmwC5F3Kr0ouhr5Kt8jkQeD/vuqYuxOAyDI egjo3Y7OGqct+5nybmbOwU0EVNPA8QEQAN/79cFVNpC+8rmudnXGbob9sk0J99qnwM2tw33v uvQjEGAJTVCOHrewDbHmqZ5V1X1LI9cMlLUNMR3W0+L04+MH8s/JxshFST+hOaijGc81AN2P NrAQD7IKpA78Q2F3I6gpbMzyMy0DxmoKF73IAMQIknrhzn37DgM+x4jQgkvhFMqnnZ/xIQ9d QEBKDtfxH78QPosDqCzsN9HRArC75TiKTKOxC12ZRNFZfEPnmqJ260oImtmoD/L8QiBsdA4m Mdkmo6Pq6iAhbGQ5phmhUVuj+7O8rTpGRXySMLZ44BimM8yHWTaiLWxCehHgfUWRNLwFbrd+ nYJYHoqyFGueZFBNxY4bS2rIEDg+nSKiAwJv3DUJDDd/QJpikB5HIjg/5kcSm7laqfbr1pmC ZbR2JCTp4FTABVLxt7pJP40SuLx5He63aA/VyxoInLcZPBNvVfq/3v3fkoILphi77ZfTvKrl RkDdH6PkFOFpnrctdTWbIFAYfU96VvySFAOOg5fsCeLv9/zD4dQEGsvva/qKZXkH/l2LeVp3 xEXoFsUZtajPZgyRBxer0nVWRyeVwUQnLG8kjEOcZzX27GUpughi8w42p4oMD+96tr3BKTAr guRHJnU1M1xwRPbw5UsNXEOgYsFc8cdto0X7hQ2Ugc07CRSDvyH50IKXf2++znOTXFDhABEB AAHCwV8EGAECAAkFAlTTwPECGwwACgkQA5OWnS12CFAdRg//ZGV0voLRjjgX9ODzaz6LP+IP /ebGLXe3I+QXz8DaTkG45evOu6B2J53IM8t1xEug0OnfnTo1z0AFg5vU53L24LAdpi12CarV Da53WvHzG4BzCVGOGrAvJnMvUXf0/aEm0Sen2Mvf5kvOwsr9UTHJ8N/ucEKSXAXf+KZLYJbL NL4LbOFP+ywxtjV+SgLpDgRotM43yCRbONUXEML64SJ2ST+uNzvilhEQT/mlDP7cY259QDk7 1K6B+/ACE3Dn7X0/kp8a+ZoNjUJZkQQY4JyMOkITD6+CJ1YsxhX+/few9k5uVrwK/Cw+Vmae A85gYfFn+OlLFO/6RGjMAKOsdtPFMltNOZoT+YjgAcW6Q9qGgtVYKcVOxusL8C3v8PAYf7Ul Su7c+/Ayr3YV9Sp8PH4X4jK/zk3+DDY1/ASE94c95DW1lpOcyx3n1TwQbwp6TzPMRe1IkkYe 0lYj9ZgKaZ8hEmzuhg6FKXk9Dah+H73LdV57M4OFN8Xwb7v+oEG23vdsb2KBVG5K6Tv7Hb2N sfHWRdU3quYIistrNWWeGmfTlhVLgDhEmAsKZFH05QsAv3pQv7dH/JD+Tbn6sSnNAVrATff1 AD3dXmt+5d3qYuUxam1UFGufGzV7jqG5QNStp0yvLP0xroB8y0CnnX2FY6bAVCU+CqKu+n1B LGlgwABHRtLCwe0EGAEIACAWIQTsOJyrwsTyXYYA0NADk5adLXYIUAUCWsTXAwIbAgCBCRAD k5adLXYIUHYgBBkWCAAdFiEEx1U9vxg1xAeUwus20p7yIq+KHe4FAlrE1wMACgkQ0p7yIq+K He6RfAEA+frSSvrHiuatNqvgYAJcraYhp1GQJrWSWMmi2eFcGskBAJyLp47etEn3xhJBLVVh 2y2K4Nobb6ZgxA4Svfnkf7AAdicQALiaOKDwKD3tgf90ypEoummYzAxv8MxyPXZ7ylRnkheA eQDxuoc/YwMA4qyxhzf6K4tD/aT12XJd95gk+YAL6flGkJD8rA3jsEucPmo5eko4Ms2rOEdG jKsZetkdPKGBd2qVxxyZgzUkgRXduvyux04b9erEpJmoIXs/lE0IRbL9A9rJ6ASjFPGpXYrb 73pb6Dtkdpvv+hoe4cKeae4dS0AnDc7LWSW3Ub0n61uk/rqpTmKuesmTZeB2GHzLN5GAXfNj ELHAeSVfFLPRFrjF5jjKJkpiyq98+oUnvTtDIPMTg05wSN2JtwKnoQ0TAIHWhiF6coGeEfY8 ikdVLSZDEjW54Td5aIXWCRTBWa6Zqz/G6oESF+Lchu/lDv5+nuN04KZRAwCpXLS++/givJWo M9FMnQSvt4N95dVQE3kDsasl960ct8OzxaxuevW0OV/jQEd9gH50RaFif412DTrsuaPsBz6O l2t2TyTuHm7wVUY2J3gJYgG723/PUGW4LaoqNrYQUr/rqo6NXw6c+EglRpm1BdpkwPwAng63 W5VOQMdnozD2RsDM5GfA4aEFi5m00tE+8XPICCtkduyWw+Z+zIqYk2v+zraPLs9Gs0X2C7X0 yvqY9voUoJjG6skkOToGZbqtMX9K4GOv9JAxVs075QRXL3brHtHONDt6udYobzz+ Message-ID: Date: Mon, 8 Apr 2019 11:52:59 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.0 MIME-Version: 1.0 In-Reply-To: <20190406001653.GA4805@ming.t460p> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/04/2019 02:16, Ming Lei wrote: > Hi Nikolay, > > On Fri, Apr 05, 2019 at 07:04:18PM +0300, Nikolay Borisov wrote: >> Hello Ming, >> >> Following the mp biovec rework what is the maximum >> data that a bio could contain? Should it be PAGE_SIZE * bio_vec > > There isn't any maximum data limit on the bio submitted from fs, > and block layer will make the final bio sent to driver correct > by applying all kinds of queue limit, such as max segment size, > max segment number, max sectors, ... Naive question, why are we creating possibly huge bios just to split them according the the LLDD's limits afterwards? Can't we look at the limits in e.g. bio_add_page() and decide if we need to split there? This is just me thinking about it, I haven't though if there are any resulting performance penalties from it, yet. Byte, Johannes -- Johannes Thumshirn SUSE Labs Filesystems jthumshirn@suse.de +49 911 74053 689 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: Felix Imendörffer, Mary Higgins, Sri Rasiah HRB 21284 (AG Nürnberg) Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850