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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id B9708C531DF for ; Mon, 12 Aug 2024 15:01:22 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E62B86B008A; Mon, 12 Aug 2024 11:01:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E12346B008C; Mon, 12 Aug 2024 11:01:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CDA5A6B0095; Mon, 12 Aug 2024 11:01:21 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id AF3E66B008A for ; Mon, 12 Aug 2024 11:01:21 -0400 (EDT) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id A0705140222 for ; Mon, 12 Aug 2024 15:01:15 +0000 (UTC) X-FDA: 82443906552.19.FAF62F3 Received: from mail-pf1-f175.google.com (mail-pf1-f175.google.com [209.85.210.175]) by imf07.hostedemail.com (Postfix) with ESMTP id A90054002E for ; Mon, 12 Aug 2024 15:01:12 +0000 (UTC) Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=YLxOyckm; spf=pass (imf07.hostedemail.com: domain of ioworker0@gmail.com designates 209.85.210.175 as permitted sender) smtp.mailfrom=ioworker0@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1723474803; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding:in-reply-to: references:dkim-signature; bh=lSAp163vx0UuVbaXPTfbO7fD1LAtlFyXrCv1ZVeziqY=; b=cZjtMJpJxIPaw1EL7zw6DIqN0IogicxE2c+MeHAvkOfxXrveC7hTkDca+ba4Ik22vGiyI+ oF/bKa4gR6doR2LROS1+sc1kfSbGLOUIdJE9v2voINwEmTfZiqq2xwkpdPjZ6rP7o6EY36 e+z9BOhhbu/X96RS7OM5gsgW0kVBroA= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1723474803; a=rsa-sha256; cv=none; b=Em2NqWYA56TfOkzgRAsZsyRWzftNFgVpABK6/GhLypc/+pOWCirJB0bwi2mQZ9cduV7Opn CB/doLe7eYzHBTXzc4AGZpFRB2T+8SoqzQ5ceO4m92GLTgTSisVVBRZeLuiHZsE+wnVnVv xvcnuokS/3fHE9iMZ1igik5XmyzbDzY= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=YLxOyckm; spf=pass (imf07.hostedemail.com: domain of ioworker0@gmail.com designates 209.85.210.175 as permitted sender) smtp.mailfrom=ioworker0@gmail.com; dmarc=pass (policy=none) header.from=gmail.com Received: by mail-pf1-f175.google.com with SMTP id d2e1a72fcca58-7107b16be12so3659631b3a.3 for ; Mon, 12 Aug 2024 08:01:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1723474871; x=1724079671; darn=kvack.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=lSAp163vx0UuVbaXPTfbO7fD1LAtlFyXrCv1ZVeziqY=; b=YLxOyckmE/wYfBzhS2bghKNNcOdaRIoL0DzRo3jpprylmVJ9YC0+4R09wdywkjK3XQ TQxUHKPkDGA4SCwyyhetbTfywnhD0LFpL1R1vArzxKkOwZkqAWec0l/hNqKvnU0feOtd DyThj9HIyyBxnAjW6HOZst1JgaVk2smeYnDd+KQqBpjIhcU50dOMCkG7N/6fnFQ595v1 WhFwIDq+i+496XNN7BI2whJM31C/Fhf9VZ34m4pRHROg7jF8jJq4cfKpQXwQlCSMEvLt 2vV3UNBK4Oh5hkNkZ5JCFeENHqhh7L/hLGdsryhj/QNwGVIXkNUyy7VZ44kj69qBzuVY uMcA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1723474871; x=1724079671; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=lSAp163vx0UuVbaXPTfbO7fD1LAtlFyXrCv1ZVeziqY=; b=gVhMpQB86rChCzDwalF5n6S/BQsnmbfuR1YGCHlz6EnYRqREsHvMYfzNjloNEqKPoe pwgiOUMDnfCGi9In9oIN7uoNaoCYlKzU6rRoiSl5wTE53mtE3Bthbzc5xIm+8BL8suKB rh/FaBvn5bAm6Ykv5W5Cy5c9NQEeuG2eQS4xod85ylw418wM9/zviVvNwf1RUtZnfCYU iMv1/glZ1X5p+lEa5HgZYqm0J4VGDr0YZM62LD3MQCRNvQZEFuol0N8RgVQaCMuzAXJ3 b6UV8uVjWoFBmXTf4K4/1CeBJyvPSTgdbpG9uYgU+xnEb1QQQV5uhXPQS6JYAFNXa4l7 tUHg== X-Gm-Message-State: AOJu0YyqEw7nUF7lHVknOp0xIqjBkAgJxwT1PGTlbWcjmRpwEereX885 HuDygPNJGuN0Rqag1FpQeCuc2a4y+arXNUhbGLI9ezwg7ndwQAfDD4Ac7g== X-Google-Smtp-Source: AGHT+IGh3SqpY5xyiidrIgiDY1lk35G5U0l0oc4IB+YQwEgHl2mDIOEsvV2Sz1kosVyBw1Tu78RqqQ== X-Received: by 2002:a05:6a21:3945:b0:1c2:8eb7:19cd with SMTP id adf61e73a8af0-1c8d758ff6emr832729637.42.1723474870466; Mon, 12 Aug 2024 08:01:10 -0700 (PDT) Received: from localhost.localdomain ([43.129.202.66]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-7c3dbea9527sm4298859a12.93.2024.08.12.08.01.06 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Mon, 12 Aug 2024 08:01:10 -0700 (PDT) From: Lance Yang To: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, cgroups@vger.kernel.org Cc: josef@toxicpanda.com, tj@kernel.org, fujita.tomonori@lab.ntt.co.jp, boqun.feng@gmail.com, a.hindborg@samsung.com, paolo.valente@unimore.it, axboe@kernel.dk, vbabka@kernel.org, mkoutny@suse.com, david@redhat.com, 21cnbao@gmail.com, baolin.wang@linux.alibaba.com, libang.li@antgroup.com, Lance Yang Subject: [BUG] cgroupv2/blk: inconsistent I/O behavior in Cgroup v2 with set device wbps and wiops Date: Mon, 12 Aug 2024 23:00:30 +0800 Message-ID: <20240812150049.8252-1-ioworker0@gmail.com> X-Mailer: git-send-email 2.45.2 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: A90054002E X-Stat-Signature: g39kk4dkzxurk1ndmp1qb7hteh6q433r X-HE-Tag: 1723474872-764729 X-HE-Meta: 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 MKM1NmP7 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.176826, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi all, I've run into a problem with Cgroup v2 where it doesn't seem to correctly limit I/O operations when I set both wbps and wiops for a device. However, if I only set wbps, then everything works as expected. To reproduce the problem, we can follow these command-based steps: 1. **System Information:** - Kernel Version and OS Release: ``` $ uname -r 6.10.0-rc5+ $ cat /etc/os-release PRETTY_NAME="Ubuntu 24.04 LTS" NAME="Ubuntu" VERSION_ID="24.04" VERSION="24.04 LTS (Noble Numbat)" VERSION_CODENAME=noble ID=ubuntu ID_LIKE=debian HOME_URL="https://www.ubuntu.com/" SUPPORT_URL="https://help.ubuntu.com/" BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/" PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy" UBUNTU_CODENAME=noble LOGO=ubuntu-logo ``` 2. **Device Information and Settings:** - List Block Devices and Scheduler: ``` $ lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS sda 8:0 0 4.4T 0 disk └─sda1 8:1 0 4.4T 0 part /data ... $ cat /sys/block/sda/queue/scheduler none [mq-deadline] kyber bfq $ cat /sys/block/sda/queue/rotational 1 ``` 3. **Reproducing the problem:** - Navigate to the cgroup v2 filesystem and configure I/O settings: ``` $ cd /sys/fs/cgroup/ $ stat -fc %T /sys/fs/cgroup cgroup2fs $ mkdir test $ echo "8:0 wbps=10485760 wiops=100000" > io.max ``` In this setup: wbps=10485760 sets the write bytes per second limit to 10 MB/s. wiops=100000 sets the write I/O operations per second limit to 100,000. - Add process to the cgroup and verify: ``` $ echo $$ > cgroup.procs $ cat cgroup.procs 3826771 3828513 $ ps -ef|grep 3826771 root 3826771 3826768 0 22:04 pts/1 00:00:00 -bash root 3828761 3826771 0 22:06 pts/1 00:00:00 ps -ef root 3828762 3826771 0 22:06 pts/1 00:00:00 grep --color=auto 3826771 ``` - Observe I/O performance using `dd` commands and `iostat`: ``` $ dd if=/dev/zero of=/data/file1 bs=512M count=1 & $ dd if=/dev/zero of=/data/file1 bs=512M count=1 & ``` ``` $ iostat -d 1 -h -y -p sda tps kB_read/s kB_wrtn/s kB_dscd/s kB_read kB_wrtn kB_dscd Device 7.00 0.0k 1.3M 0.0k 0.0k 1.3M 0.0k sda 7.00 0.0k 1.3M 0.0k 0.0k 1.3M 0.0k sda1 tps kB_read/s kB_wrtn/s kB_dscd/s kB_read kB_wrtn kB_dscd Device 5.00 0.0k 1.2M 0.0k 0.0k 1.2M 0.0k sda 5.00 0.0k 1.2M 0.0k 0.0k 1.2M 0.0k sda1 tps kB_read/s kB_wrtn/s kB_dscd/s kB_read kB_wrtn kB_dscd Device 21.00 0.0k 1.4M 0.0k 0.0k 1.4M 0.0k sda 21.00 0.0k 1.4M 0.0k 0.0k 1.4M 0.0k sda1 tps kB_read/s kB_wrtn/s kB_dscd/s kB_read kB_wrtn kB_dscd Device 5.00 0.0k 1.2M 0.0k 0.0k 1.2M 0.0k sda 5.00 0.0k 1.2M 0.0k 0.0k 1.2M 0.0k sda1 tps kB_read/s kB_wrtn/s kB_dscd/s kB_read kB_wrtn kB_dscd Device 5.00 0.0k 1.2M 0.0k 0.0k 1.2M 0.0k sda 5.00 0.0k 1.2M 0.0k 0.0k 1.2M 0.0k sda1 tps kB_read/s kB_wrtn/s kB_dscd/s kB_read kB_wrtn kB_dscd Device 1848.00 0.0k 448.1M 0.0k 0.0k 448.1M 0.0k sda 1848.00 0.0k 448.1M 0.0k 0.0k 448.1M 0.0k sda1 ``` Initially, the write speed is slow (<2MB/s) then suddenly bursts to several hundreds of MB/s. - Testing with wiops set to max: ``` echo "8:0 wbps=10485760 wiops=max" > io.max $ dd if=/dev/zero of=/data/file1 bs=512M count=1 & $ dd if=/dev/zero of=/data/file1 bs=512M count=1 & ``` ``` $ iostat -d 1 -h -y -p sda tps kB_read/s kB_wrtn/s kB_dscd/s kB_read kB_wrtn kB_dscd Device 48.00 0.0k 10.0M 0.0k 0.0k 10.0M 0.0k sda 48.00 0.0k 10.0M 0.0k 0.0k 10.0M 0.0k sda1 tps kB_read/s kB_wrtn/s kB_dscd/s kB_read kB_wrtn kB_dscd Device 40.00 0.0k 10.0M 0.0k 0.0k 10.0M 0.0k sda 40.00 0.0k 10.0M 0.0k 0.0k 10.0M 0.0k sda1 tps kB_read/s kB_wrtn/s kB_dscd/s kB_read kB_wrtn kB_dscd Device 41.00 0.0k 10.0M 0.0k 0.0k 10.0M 0.0k sda 41.00 0.0k 10.0M 0.0k 0.0k 10.0M 0.0k sda1 tps kB_read/s kB_wrtn/s kB_dscd/s kB_read kB_wrtn kB_dscd Device 46.00 0.0k 10.0M 0.0k 0.0k 10.0M 0.0k sda 46.00 0.0k 10.0M 0.0k 0.0k 10.0M 0.0k sda1 tps kB_read/s kB_wrtn/s kB_dscd/s kB_read kB_wrtn kB_dscd Device 55.00 0.0k 10.2M 0.0k 0.0k 10.2M 0.0k sda 55.00 0.0k 10.2M 0.0k 0.0k 10.2M 0.0k sda1 ``` The iostat output shows the write operations as stabilizing at around 10 MB/s, which aligns with the defined limit of 10 MB/s. After setting wiops to max, the I/O limits appear to work as expected. Thanks, Lance