From patchwork Fri Apr 2 19:16:31 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Schatzberg X-Patchwork-Id: 12181419 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=-8.5 required=3.0 tests=BAYES_00,DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_GIT 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 DB860C433B4 for ; Fri, 2 Apr 2021 19:16:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9BDF261155 for ; Fri, 2 Apr 2021 19:16:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229722AbhDBTQ6 (ORCPT ); Fri, 2 Apr 2021 15:16:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51952 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229553AbhDBTQ6 (ORCPT ); Fri, 2 Apr 2021 15:16:58 -0400 Received: from mail-qk1-x730.google.com (mail-qk1-x730.google.com [IPv6:2607:f8b0:4864:20::730]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5EEE4C0613E6; Fri, 2 Apr 2021 12:16:55 -0700 (PDT) Received: by mail-qk1-x730.google.com with SMTP id g20so6118176qkk.1; Fri, 02 Apr 2021 12:16:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=LnxM2dCsgefp2lTqtmiMsTgHl3EHT3phtkcM0CuctsU=; b=sexUDEANAJW6Wcofc3gTufIIY3OVzBHVz66e60XJSMOYq0momOVoT1/oSTROjNQAyO D8/s6Joupk3LV08oTkklRtksM5DRiYMbzCopEdPBUGrn8O3zoOAipt71aFRGv2ZanlBl vO2GozZTnPskqZfhgTlFk95cwMNQU+m339bV7RkCZSySqCTRmQHot0CU2gqFG66di69J NLYQSNDERUfyzQHXHoVwSYJHd/ZLxBf5wdfiYR1w8ySfWzTwxxMx3ryHMA+WgOWaXbWQ HhzFx3Yldxiyuf0WWLuAGodViVzYnMi84D2KpIbOaqfNTgwTJ/LjUaGqp4slRUQ2cuam kDig== 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:mime-version :content-transfer-encoding; bh=LnxM2dCsgefp2lTqtmiMsTgHl3EHT3phtkcM0CuctsU=; b=kn/o4wFAE2TSja/Z96NVRsXLZjW71paFPM9W/YP4Fwyzj3YbWZbDxFg7TC0q8YsNcW TLolsgOnoQvgS19T4Op4zjYvhLIqKy74XQuFkE93xGtMzoVLx5FRQ9JKC8qzN6tIL49c IFguNeMchQZFvo7q9ds9Mh4KDx/22LhPGfOaAADz242cavv9HRhD7a2VZNz9DuGcMziO Juca2r0E07OnuVRtfoz3FNcXF27btlklznTdpr/JCEhEpNauMOTGBO78Xc0LlIrn3e3L NV16XyzfPgZLXdAQhG7fmFy87fdPH7UMOMh47eTiGfseHQY5cpkZcm3EE8Y2oznXrWMd 3P5g== X-Gm-Message-State: AOAM5306qQEnXdXA4OIjAODxph8o3w1iPZGprR0YCSV8ub+eoyaM7SGC qvhTsFLAhWbhn/rvjclOTAo= X-Google-Smtp-Source: ABdhPJwX8tAxkyjY8aBDhXkRVII0oYwE89H2KF7yGu+5YPIVNFwoLTbHccGDT2YUkcfkBge9vSr0rw== X-Received: by 2002:a05:620a:14ac:: with SMTP id x12mr14322165qkj.409.1617391014210; Fri, 02 Apr 2021 12:16:54 -0700 (PDT) Received: from localhost ([2620:10d:c091:480::1:ae82]) by smtp.gmail.com with ESMTPSA id w197sm7967261qkb.89.2021.04.02.12.16.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 Apr 2021 12:16:53 -0700 (PDT) From: Dan Schatzberg Cc: Jens Axboe , Tejun Heo , Zefan Li , Johannes Weiner , Andrew Morton , Michal Hocko , Vladimir Davydov , Hugh Dickins , Shakeel Butt , Roman Gushchin , Muchun Song , Yang Shi , Alex Shi , Alexander Duyck , Wei Yang , linux-block@vger.kernel.org (open list:BLOCK LAYER), linux-kernel@vger.kernel.org (open list), cgroups@vger.kernel.org (open list:CONTROL GROUP (CGROUP)), linux-mm@kvack.org (open list:MEMORY MANAGEMENT) Subject: [PATCH V12 0/3] Charge loop device i/o to issuing cgroup Date: Fri, 2 Apr 2021 12:16:31 -0700 Message-Id: <20210402191638.3249835-1-schatzberg.dan@gmail.com> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org No major changes, rebased on top of latest mm tree Changes since V12: * Small change to get_mem_cgroup_from_mm to avoid needing get_active_memcg Changes since V11: * Removed WQ_MEM_RECLAIM flag from loop workqueue. Technically, this can be driven by writeback, but this was causing a warning in xfs and likely other filesystems aren't equipped to be driven by reclaim at the VFS layer. * Included a small fix from Colin Ian King. * reworked get_mem_cgroup_from_mm to institute the necessary charge priority. Changes since V10: * Added page-cache charging to mm: Charge active memcg when no mm is set Changes since V9: * Rebased against linus's branch which now includes Roman Gushchin's patch this series is based off of Changes since V8: * Rebased on top of Roman Gushchin's patch (https://lkml.org/lkml/2020/8/21/1464) which provides the nesting support for setting active memcg. Dropped the patch from this series that did the same thing. Changes since V7: * Rebased against linus's branch Changes since V6: * Added separate spinlock for worker synchronization * Minor style changes Changes since V5: * Fixed a missing css_put when failing to allocate a worker * Minor style changes Changes since V4: Only patches 1 and 2 have changed. * Fixed irq lock ordering bug * Simplified loop detach * Added support for nesting memalloc_use_memcg Changes since V3: * Fix race on loop device destruction and deferred worker cleanup * Ensure charge on shmem_swapin_page works just like getpage * Minor style changes Changes since V2: * Deferred destruction of workqueue items so in the common case there is no allocation needed Changes since V1: * Split out and reordered patches so cgroup charging changes are separate from kworker -> workqueue change * Add mem_css to struct loop_cmd to simplify logic The loop device runs all i/o to the backing file on a separate kworker thread which results in all i/o being charged to the root cgroup. This allows a loop device to be used to trivially bypass resource limits and other policy. This patch series fixes this gap in accounting. A simple script to demonstrate this behavior on cgroupv2 machine: ''' #!/bin/bash set -e CGROUP=/sys/fs/cgroup/test.slice LOOP_DEV=/dev/loop0 if [[ ! -d $CGROUP ]] then sudo mkdir $CGROUP fi grep oom_kill $CGROUP/memory.events # Set a memory limit, write more than that limit to tmpfs -> OOM kill sudo unshare -m bash -c " echo \$\$ > $CGROUP/cgroup.procs; echo 0 > $CGROUP/memory.swap.max; echo 64M > $CGROUP/memory.max; mount -t tmpfs -o size=512m tmpfs /tmp; dd if=/dev/zero of=/tmp/file bs=1M count=256" || true grep oom_kill $CGROUP/memory.events # Set a memory limit, write more than that limit through loopback # device -> no OOM kill sudo unshare -m bash -c " echo \$\$ > $CGROUP/cgroup.procs; echo 0 > $CGROUP/memory.swap.max; echo 64M > $CGROUP/memory.max; mount -t tmpfs -o size=512m tmpfs /tmp; truncate -s 512m /tmp/backing_file losetup $LOOP_DEV /tmp/backing_file dd if=/dev/zero of=$LOOP_DEV bs=1M count=256; losetup -D $LOOP_DEV" || true grep oom_kill $CGROUP/memory.events ''' Naively charging cgroups could result in priority inversions through the single kworker thread in the case where multiple cgroups are reading/writing to the same loop device. This patch series does some minor modification to the loop driver so that each cgroup can make forward progress independently to avoid this inversion. With this patch series applied, the above script triggers OOM kills when writing through the loop device as expected. Dan Schatzberg (3): loop: Use worker per cgroup instead of kworker mm: Charge active memcg when no mm is set loop: Charge i/o to mem and blk cg drivers/block/loop.c | 244 ++++++++++++++++++++++++++++++------- drivers/block/loop.h | 15 ++- include/linux/memcontrol.h | 6 + kernel/cgroup/cgroup.c | 1 + mm/filemap.c | 2 +- mm/memcontrol.c | 49 +++++--- mm/shmem.c | 4 +- 7 files changed, 253 insertions(+), 68 deletions(-)