From patchwork Mon Apr 20 22:39:28 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Schatzberg X-Patchwork-Id: 11500025 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0240F6CA for ; Mon, 20 Apr 2020 22:41:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D8FE320BED for ; Mon, 20 Apr 2020 22:41:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ZTvAXfQi" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726325AbgDTWlY (ORCPT ); Mon, 20 Apr 2020 18:41:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42700 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725958AbgDTWlX (ORCPT ); Mon, 20 Apr 2020 18:41:23 -0400 Received: from mail-qt1-x844.google.com (mail-qt1-x844.google.com [IPv6:2607:f8b0:4864:20::844]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 84352C061A0C; Mon, 20 Apr 2020 15:41:23 -0700 (PDT) Received: by mail-qt1-x844.google.com with SMTP id c16so10125395qtv.1; Mon, 20 Apr 2020 15:41:23 -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=DYVGKptuNao3T/Cw5MVydseWWvnB3P8P6bY7urNsYE4=; b=ZTvAXfQirkhPYwWin4gaTNuQ42l+Obs3whqemoax3hucfHKWlC19ImBWdeBO0MYz9S KrjfYP5kNdW+Sg5lblu5swpCyPtMN/naDZ2SlCHqd+5jkTR7aMofBNTfCBzhFPcxS3TB tbPix1/O9HErM8CNUqIyTj8QqgF3AO4ZCfjCAKlc3HLIj5a0cYQ68ebLK8yX3baCZihs L0iJTd31iGBMC91rn/1DaFPSOakptQYq5ZT5FC16X+JZTM2GMDNsZ34n93sI1+2FybVF NxG/Rqg8po4ejbaExawn8ZKMfICTrgTxHOBJOAGW85lEjsUcfSf9AgItY4xRQvkI+Nm+ dpNQ== 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=DYVGKptuNao3T/Cw5MVydseWWvnB3P8P6bY7urNsYE4=; b=nx07pM4s/AynQQIhdFNIqt68+qUIaGelLikkq0AO0aApJHNig/g13VIMXtFKQWqsS7 sPfBhJrRQxIK08Q9tsnce2z9dWQi5vIG7tUckiJixI5yRS5ZuUig2mVtqABfwqGZM015 uNTBrRwYarW6/dytvlAjEZsRAQ4DY1wIBODIrD7i4GzQrt9TE28Noak1O3Qa9UFVL+ut zGW/k+txTjDe0HEyBPSOx+HKI7eeIwbDfP2ie//eIvdpZvPonqLaoEoN9Y2ufi9GfZiO Zq/I4QOOqDSc4z/Z7ahpI8jDjnLrQiK5zh7/4d+3ycUW4FU756xfLpGS1ga8lUboDQ2D RbFw== X-Gm-Message-State: AGi0PuZeCu2lHMXiqHBddUbllegsIVe3XOYibJHfAYBno+BNAK1HULQP iCfajYJMh/Vj/QyOUyjMHaI= X-Google-Smtp-Source: APiQypLCIw7/eZknDKLM+t8IKYdj7N+Co65p6dBEo98Q2IzOK0LygWK0Y7J1AaH2soSrsIhgmgtdEA== X-Received: by 2002:ac8:19fd:: with SMTP id s58mr18784474qtk.354.1587422482527; Mon, 20 Apr 2020 15:41:22 -0700 (PDT) Received: from dschatzberg-fedora-PC0Y6AEN.thefacebook.com ([2620:10d:c091:480::1:b0d9]) by smtp.gmail.com with ESMTPSA id j90sm511052qte.20.2020.04.20.15.41.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Apr 2020 15:41:21 -0700 (PDT) From: Dan Schatzberg Cc: Dan Schatzberg , Jens Axboe , Alexander Viro , Jan Kara , Amir Goldstein , Tejun Heo , Li Zefan , Johannes Weiner , Michal Hocko , Vladimir Davydov , Andrew Morton , Hugh Dickins , Roman Gushchin , Shakeel Butt , Chris Down , Yang Shi , Ingo Molnar , "Peter Zijlstra (Intel)" , Mathieu Desnoyers , Andrea Arcangeli , Thomas Gleixner , linux-block@vger.kernel.org (open list:BLOCK LAYER), linux-kernel@vger.kernel.org (open list), linux-fsdevel@vger.kernel.org (open list:FILESYSTEMS (VFS and infrastructure)), cgroups@vger.kernel.org (open list:CONTROL GROUP (CGROUP)), linux-mm@kvack.org (open list:CONTROL GROUP - MEMORY RESOURCE CONTROLLER (MEMCG)) Subject: [PATCH 0/4] Charge loop device i/o to issuing cgroup Date: Mon, 20 Apr 2020 18:39:28 -0400 Message-Id: <20200420223936.6773-1-schatzberg.dan@gmail.com> X-Mailer: git-send-email 2.21.1 MIME-Version: 1.0 To: unlisted-recipients:; (no To-header on input) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org 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 (4): loop: Use worker per cgroup instead of kworker mm: support nesting memalloc_use_memcg() mm: Charge active memcg when no mm is set loop: Charge i/o to mem and blk cg drivers/block/loop.c | 246 ++++++++++++++++++++++----- drivers/block/loop.h | 14 +- fs/buffer.c | 6 +- fs/notify/fanotify/fanotify.c | 5 +- fs/notify/inotify/inotify_fsnotify.c | 5 +- include/linux/memcontrol.h | 6 + include/linux/sched/mm.h | 28 +-- kernel/cgroup/cgroup.c | 1 + mm/memcontrol.c | 11 +- mm/shmem.c | 4 +- 10 files changed, 246 insertions(+), 80 deletions(-)