From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 78FD22629D; Fri, 15 Nov 2024 01:14:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.51 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731633281; cv=none; b=h2qjMBPUjV9wVUQMfujn+QySv1/NbpIU4oe2ZdA5pZDovFCCgG56Ja9I/VRx2tmLJ7/382ILw3KwP7lVXjj7rJ6Hv97OiyoMOWaVKgwRInH1tFtq9gDgqpB4bCAjtB2atCiRHpJAhR1nEo4rkfIvQ6b0YDWkKbIB77fnGK86p8o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731633281; c=relaxed/simple; bh=ahzNLmvMNb/cOjUYom6iAdTIYn9HWcDKXlYNbiV3aoQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=d7XZ1vsUSWJCL7yuZ/V44okLwNiw306eK4ogvujB2a1DLtsf2718ujhmyXHkUrGOODzZFkFFaYdAQjrWuwRRXQXd44qLnzNGAewwvgLMuacyvZhHPlDaR3+aPsX52pBmQSrAz6/8SwQoKi4qJPV3BQcGpCS5aPOQG5a7Ry3phq8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=none smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.93.142]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4XqJvW1YL4z4f3nT9; Fri, 15 Nov 2024 09:14:15 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.112]) by mail.maildlp.com (Postfix) with ESMTP id 6673C1A0359; Fri, 15 Nov 2024 09:14:34 +0800 (CST) Received: from [10.67.109.79] (unknown [10.67.109.79]) by APP1 (Coremail) with SMTP id cCh0CgB3bK54oDZnQ0EVBw--.17204S2; Fri, 15 Nov 2024 09:14:34 +0800 (CST) Message-ID: <2f755161-ec7e-4785-b0ca-ea68c01785a2@huaweicloud.com> Date: Fri, 15 Nov 2024 09:14:32 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] freezer, sched: report the frozen task stat as 'D' To: Tejun Heo Cc: Valentin Schneider , mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, =?UTF-8?Q?mkoutny=40suse=2Ecom_=3E=3E_Michal_Koutn=C3=BD?= , linux-kernel@vger.kernel.org, wangweiyang2@huawei.com, cgroups@vger.kernel.org References: <20241111135431.1813729-1-chenridong@huaweicloud.com> <4f78d752-52ab-493d-8bf5-f12dc4f554c8@huaweicloud.com> Content-Language: en-US From: Chen Ridong In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CM-TRANSID:cCh0CgB3bK54oDZnQ0EVBw--.17204S2 X-Coremail-Antispam: 1UD129KBjvJXoW7CF1xXw4DXrWxKw4xurWfZrb_yoW8Xw1rpF ZYk3Z8t3Z7KryqkrnFv3Z7WFyUtrs2qry5XFykGFWxGFnxXrn09ryIvryYgan0krWSyFyU Za1Ygas7ZrW7ArUanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUv0b4IE77IF4wAFF20E14v26r4j6ryUM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rwA2F7IY1VAKz4 vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_tr0E3s1l84ACjcxK6xIIjxv20xvEc7Cj xVAFwI0_Gr1j6F4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x 0267AKxVW0oVCq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG 6I80ewAv7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFV Cjc4AY6r1j6r4UM4x0Y48IcVAKI48JM4IIrI8v6xkF7I0E8cxan2IY04v7MxkF7I0En4kS 14v26r1q6r43MxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I 8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUtVW8 ZwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x 0267AKxVW8JVWxJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_ Jr0_Gr1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7IU1 7KsUUUUUU== X-CM-SenderInfo: hfkh02xlgr0w46kxt4xhlfz01xgou0bp/ On 2024/11/15 0:44, Tejun Heo wrote: > Hello, > > On Thu, Nov 14, 2024 at 03:47:58PM +0800, Chen Ridong wrote: >> On 2024/11/13 22:34, Valentin Schneider wrote: >>> On 11/11/24 13:54, Chen Ridong wrote: >>>> From: Chen Ridong >>>> >>>> Before the commit f5d39b020809 ("freezer,sched: Rewrite core freezer >>>> logic"), the frozen task stat was reported as 'D' in cgroup v1. >>>> However, after rewriting core freezer logic, the frozen task stat is >>>> reported as 'R'. This is confusing, especially when a task with stat of >>>> 'S' is frozen. >>>> >>>> This can be reproduced as bellow step: >>>> cd /sys/fs/cgroup/freezer/ >>>> mkdir test >>>> sleep 1000 & >>>> [1] 739 // task whose stat is 'S' >>>> echo 739 > test/cgroup.procs >>>> echo FROZEN > test/freezer.state >>>> ps -aux | grep 739 >>>> root 739 0.1 0.0 8376 1812 pts/0 R 10:56 0:00 sleep 1000 >>>> >>>> As shown above, a task whose stat is 'S' was changed to 'R' when it was >>>> frozen. To solve this issue, simply maintain the same reported state as >>>> before the rewrite. > > The whole point of the freezer rewrite was preventing userspace from causing > arbitrary and indefinite D states which leads to all sorts of problems. The > tasks in cgroup2 freezer are *not* in uninterruptible sleeps. They are in > task stop loops and thus can be killed, ptraced and so on. It *should* > report S. > > Thanks. > Hi, Tj, There is no ambiguity what cgroup v2 shows. However, in cgroup v1, the frozen tasks are reported as 'R'. Do you think this is reseanable? Thanks, Ridong