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Mon, 8 Apr 2019 10:22:24 +0000 (UTC) Subject: Re: Possible bio merging breakage in mp bio rework To: Ming Lei Cc: Nikolay Borisov , Jens Axboe , Omar Sandoval , linux-block@vger.kernel.org, LKML , linux-btrfs References: <59c19acf-999f-1911-b0b8-1a5cec8116c5@suse.com> <20190406001653.GA4805@ming.t460p> <20190408101903.GC19589@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 12:22:22 +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: <20190408101903.GC19589@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 08/04/2019 12:19, Ming Lei wrote: > bio_add_page() is absolutely the fast path, and it is much more efficient > to apply the limit just once in the queue's .make_request_fn. You're right, this makes sense. Thanks, 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