From patchwork Mon Nov 26 21:19:33 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dennis Zhou X-Patchwork-Id: 10699163 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id BA74513AD for ; Mon, 26 Nov 2018 21:19:55 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AA7572A55B for ; Mon, 26 Nov 2018 21:19:55 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9BDFE2A610; Mon, 26 Nov 2018 21:19:55 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9F8C02A584 for ; Mon, 26 Nov 2018 21:19:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726315AbeK0IPS (ORCPT ); Tue, 27 Nov 2018 03:15:18 -0500 Received: from mail-yb1-f196.google.com ([209.85.219.196]:46040 "EHLO mail-yb1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726296AbeK0IPS (ORCPT ); Tue, 27 Nov 2018 03:15:18 -0500 Received: by mail-yb1-f196.google.com with SMTP id f6-v6so6701385ybg.12; Mon, 26 Nov 2018 13:19:52 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=8rMoiDmdRPmR3hN5zZipHlN1I4Sy3AxFGp9yVlEAyEw=; b=mBuOM7+I7/852olIYpBQ8q6QOzjphpUDUJZhKsStU2a7jgPTxRVay6EsP0fhDTYguc g/fCt3IWVobU4Uf8wyLL5+2ug8KICmDgwzbJ6X5mscPDtXzNMJf4EaQ9e0zID/ZZVtOY 4NbnZ99ODvh4BYa0oj+PVjP0Brf6z3E4Pi6H7cFN0UuUd9FfbqR2jntPmRR4660JQnwQ R4x6/W/UbTQzgTa2n/OV4UH+7TR/AQ8eKl64kUVvSMdSOkxYaEZ9lHMTpMWjD5GIlpKA 5OkH0/S9snoD4uFzjTcqyn906BqAzfWSWNtdPievKlN33hqhBXUOj8nUALNlnu6uaPpY GZHg== X-Gm-Message-State: AA+aEWZHEyfhHzK2JsgJOqrButF2j/gkTDqHWTOgtG6da/g9j1SlfOh+ BcP7kybTpuN7H0GMOuGcIDE= X-Google-Smtp-Source: AFSGD/VD8wzsw3a6HHAWKXZGkNEhl+bUQMV1BTZx/LUmSRZywffk9IU2Vw6N0sROIynASzFQ8K/ktA== X-Received: by 2002:a25:e80d:: with SMTP id k13-v6mr29537108ybd.420.1543267191928; Mon, 26 Nov 2018 13:19:51 -0800 (PST) Received: from dennisz-mbp.thefacebook.com ([199.201.65.135]) by smtp.gmail.com with ESMTPSA id d135-v6sm495462ywh.43.2018.11.26.13.19.50 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 26 Nov 2018 13:19:51 -0800 (PST) From: Dennis Zhou To: Jens Axboe , Tejun Heo , Johannes Weiner , Josef Bacik Cc: kernel-team@fb.com, linux-block@vger.kernel.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Dennis Zhou Subject: [PATCH 00/13 v4] block: always associate blkg and refcount cleanup Date: Mon, 26 Nov 2018 16:19:33 -0500 Message-Id: <20181126211946.77067-1-dennis@kernel.org> X-Mailer: git-send-email 2.13.5 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Hi everyone, This is respin of v3 [1] with fixes for the errors reported in [2] and [3]. v3 was reverted in [4]. The issue in [3] was that bio->bi_disk->queue and blkg->q were out of sync. So when I changed blk_get_rl() to use blkg->q, the wrong queue was returned and elevator from q->elevator->type threw a NPE. Note, with v4.21, the old block stack was removed and so this patch was dropped. I did backport this to v4.20 and verified this series does not encounter the error. The biggest changes in v4 are when association occurs and clearly defining the cases where association should happen. 1. Association is now done when the device is set to keep blkg->q and bio->bi_disk->queue in sync. 2. When a bio is submitted directly to the device, it will not be associated with a blkg. This is because a blkg represents the relationship between a blkcg and a request_queue. Going directly to the device means the request_queue may not exist meaning no blkg will exist. The patch updating blk_get_rl() was dropped (v3 10/12). The patch to always associate a blkg from v3 (v3 04/12) was fixed and split into patches 0004 and 0005. 0011 is new removing bio_disassociate_task(). Summarizing the ideas of this series: 1. Gracefully handle blkg failure to create by walking up the blkg tree rather than fall through to root. 2. Associate a bio with a blkg in core logic rather than per controller logic. 3. Rather than have a css and blkg reference, hold just a blkg ref as it also holds a css ref. 4. Switch to percpu ref counting for blkg. [1] https://lore.kernel.org/lkml/20180911184137.35897-1-dennisszhou@gmail.com/ [2] https://lore.kernel.org/lkml/13987.1539646128@turing-police.cc.vt.edu/ [3] https://marc.info/?l=linux-cgroups&m=154110436103723 [4] https://lore.kernel.org/lkml/20181101212410.47569-1-dennis@kernel.org/ This patchset contains the following 13 patches: 0001-blkcg-fix-ref-count-issue-with-bio_blkcg-using-task_.patch 0002-blkcg-update-blkg_lookup_create-to-do-locking.patch 0003-blkcg-convert-blkg_lookup_create-to-find-closest-blk.patch 0004-blkcg-introduce-common-blkg-association-logic.patch 0005-blkcg-associate-blkg-when-associating-a-device.patch 0006-blkcg-consolidate-bio_issue_init-to-be-a-part-of-cor.patch 0007-blkcg-associate-a-blkg-for-pages-being-evicted-by-sw.patch 0008-blkcg-associate-writeback-bios-with-a-blkg.patch 0009-blkcg-remove-bio-bi_css-and-instead-use-bio-bi_blkg.patch 0010-blkcg-remove-additional-reference-to-the-css.patch 0011-blkcg-remove-bio_disassociate_task.patch 0012-blkcg-change-blkg-reference-counting-to-use-percpu_r.patch 0013-blkcg-rename-blkg_try_get-to-blkg_tryget.patch This patchset is on top of linux-block#for-4.21/block 5f0ed774ed29. diffstats below: Dennis Zhou (13): blkcg: fix ref count issue with bio_blkcg() using task_css blkcg: update blkg_lookup_create() to do locking blkcg: convert blkg_lookup_create() to find closest blkg blkcg: introduce common blkg association logic blkcg: associate blkg when associating a device blkcg: consolidate bio_issue_init() to be a part of core blkcg: associate a blkg for pages being evicted by swap blkcg: associate writeback bios with a blkg blkcg: remove bio->bi_css and instead use bio->bi_blkg blkcg: remove additional reference to the css blkcg: remove bio_disassociate_task() blkcg: change blkg reference counting to use percpu_ref blkcg: rename blkg_try_get() to blkg_tryget() Documentation/admin-guide/cgroup-v2.rst | 8 +- block/bfq-cgroup.c | 4 +- block/bfq-iosched.c | 2 +- block/bio.c | 189 ++++++++++++++++-------- block/blk-cgroup.c | 97 ++++++++++-- block/blk-iolatency.c | 24 +-- block/blk-throttle.c | 11 -- block/bounce.c | 4 +- drivers/block/loop.c | 5 +- drivers/md/raid0.c | 2 +- fs/buffer.c | 12 +- fs/ext4/page-io.c | 4 +- include/linux/bio.h | 34 +++-- include/linux/blk-cgroup.h | 119 ++++++++++----- include/linux/blk_types.h | 7 +- include/linux/cgroup.h | 2 + include/linux/writeback.h | 5 +- kernel/cgroup/cgroup.c | 48 ++++-- kernel/trace/blktrace.c | 4 +- mm/page_io.c | 4 +- 20 files changed, 396 insertions(+), 189 deletions(-) Thanks, Dennis