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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no 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 57B99C33CB3 for ; Thu, 16 Jan 2020 12:36:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 38B5D2087E for ; Thu, 16 Jan 2020 12:36:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726553AbgAPMgi (ORCPT ); Thu, 16 Jan 2020 07:36:38 -0500 Received: from relay.sw.ru ([185.231.240.75]:39058 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726088AbgAPMgh (ORCPT ); Thu, 16 Jan 2020 07:36:37 -0500 Received: from dhcp-172-16-24-104.sw.ru ([172.16.24.104] helo=localhost.localdomain) by relay.sw.ru with esmtp (Exim 4.92.3) (envelope-from ) id 1is4NM-0000yM-QR; Thu, 16 Jan 2020 15:35:52 +0300 Subject: [PATCH block v2 0/3] block: Introduce REQ_NOZERO flag for REQ_OP_WRITE_ZEROES operation From: Kirill Tkhai To: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, martin.petersen@oracle.com, axboe@kernel.dk, tytso@mit.edu, adilger.kernel@dilger.ca, Chaitanya.Kulkarni@wdc.com, darrick.wong@oracle.com, ming.lei@redhat.com, osandov@fb.com, jthumshirn@suse.de, minwoo.im.dev@gmail.com, damien.lemoal@wdc.com, andrea.parri@amarulasolutions.com, hare@suse.com, tj@kernel.org, ajay.joshi@wdc.com, sagi@grimberg.me, dsterba@suse.com, chaitanya.kulkarni@wdc.com, bvanassche@acm.org, dhowells@redhat.com, asml.silence@gmail.com, ktkhai@virtuozzo.com Date: Thu, 16 Jan 2020 15:35:51 +0300 Message-ID: <157917805422.88675.6477661554332322975.stgit@localhost.localdomain> User-Agent: StGit/0.19 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (was "[PATCH RFC 0/3] block,ext4: Introduce REQ_OP_ASSIGN_RANGE to reflect extents allocation in block device internals") v2: Introduce new flag for REQ_OP_WRITE_ZEROES instead of introduction a new operation as suggested by Martin K. Petersen. Removed ext4-related patch to focus on block changes for now. Information about continuous extent placement may be useful for some block devices. Say, distributed network filesystems, which provide block device interface, may use this information for better blocks placement over the nodes in their cluster, and for better performance. Block devices, which map a file on another filesystem (loop), may request the same length extent on underlining filesystem for less fragmentation and for batching allocation requests. Also, hypervisors like QEMU may use this information for optimization of cluster allocations. This patchset introduces REQ_NOZERO flag for REQ_OP_WRITE_ZEROES, which makes a block device to allocate blocks instead of actual blocks zeroing. This may be used for forwarding user's fallocate(0) requests into block device internals. E.g., in loop driver this will result in allocation extents in backing-file, so subsequent write won't fail by the reason of no available space. Distributed network filesystems will be able to assign specific servers for specific extents, so subsequent write will be more efficient. Patch [1/3] is preparation, patch [2/3] introduces REQ_NOZERO flag and implements all the logic, patch [3/3] adds loop as the first user of the flag. Note, that here is only block-related patches, example of usage for ext4 with a performance numbers may be seen in [1]. [1] https://lore.kernel.org/linux-ext4/157599697369.12112.10138136904533871162.stgit@localhost.localdomain/T/#me5bdd5cc313e14de615d81bea214f355ae975db0 --- Kirill Tkhai (3): block: Add @flags argument to bdev_write_zeroes_sectors() block: Add support for REQ_NOZERO flag loop: Add support for REQ_NOZERO block/blk-core.c | 6 +++--- block/blk-lib.c | 17 ++++++++++------- block/blk-merge.c | 9 ++++++--- block/blk-settings.c | 17 +++++++++++++++++ drivers/block/loop.c | 15 ++++++++++++--- drivers/md/dm-kcopyd.c | 2 +- drivers/target/target_core_iblock.c | 4 ++-- fs/block_dev.c | 4 ++++ include/linux/blk_types.h | 5 ++++- include/linux/blkdev.h | 34 ++++++++++++++++++++++++++-------- 10 files changed, 85 insertions(+), 28 deletions(-) -- Signed-off-by: Kirill Tkhai