From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from dggsgout12.his.huawei.com (dggsgout12.his.huawei.com [45.249.212.56]) (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 B61482C3246; Thu, 31 Jul 2025 11:53:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753962789; cv=none; b=tH0DzBmmpgU1In9C5Dno0GHjJseDMtVROhTUmucvwx/bORsVsGjWQ+oWgOJy0ahMZdkPzc7dQ9ysYHsYLgc9zFdbW3QsiJRDkUncCaVNt4zDH4obSTkrJRMsnTcXZRbXnQ0Qij2QHlv4Dn0wTwLTu+oudosdZ9ji2wHNPwGWGvI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753962789; c=relaxed/simple; bh=4gSaWiwQEZvY2HR0uoKh1Gfjy+aPzU3Hy9DmKDta9JY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=UqfYyOzXt+fZmIOCW0iv0hp2fXFJ/3K2TE0RbuWYNywWUUKFkhVMG6RnFXvHwWFzGHv4mXW7JRpDTiGVfDzS032ih9TTOFn2Yu7UFGcy6ULDE87DCif/bH75sl70bvjcrVg5RVAmLURc/vhk5wkedu80TR8GiPLjIqeo4Y6OIjQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.235]) by dggsgout12.his.huawei.com (SkyGuard) with ESMTPS id 4bt6sY2cd8zKHMl3; Thu, 31 Jul 2025 19:53:05 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.252]) by mail.maildlp.com (Postfix) with ESMTP id 45EF61A0B51; Thu, 31 Jul 2025 19:53:04 +0800 (CST) Received: from [10.67.109.79] (unknown [10.67.109.79]) by APP3 (Coremail) with SMTP id _Ch0CgCHAdweWYtoViA_CA--.22541S2; Thu, 31 Jul 2025 19:53:04 +0800 (CST) Message-ID: <4fdf0c5b-54ce-474a-a2c7-8b99322ff30e@huaweicloud.com> Date: Thu, 31 Jul 2025 19:53:02 +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 v2 -next] cgroup: remove offline draining in root destruction to avoid hung_tasks To: =?UTF-8?Q?Michal_Koutn=C3=BD?= Cc: tj@kernel.org, hannes@cmpxchg.org, lizefan@huawei.com, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, lujialin4@huawei.com, chenridong@huawei.com, gaoyingjie@uniontech.com References: <20250722112733.4113237-1-chenridong@huaweicloud.com> <7f36d0c7-3476-4bc6-b66e-48496a8be514@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:_Ch0CgCHAdweWYtoViA_CA--.22541S2 X-Coremail-Antispam: 1UD129KBjDUn29KB7ZKAUJUUUUU529EdanIXcx71UUUUU7v73 VFW2AGmfu7bjvjm3AaLaJ3UjIYCTnIWjp_UUUYU7kC6x804xWl14x267AKxVW8JVW5JwAF c2x0x2IEx4CE42xK8VAvwI8IcIk0rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII 0Yj41l84x0c7CEw4AK67xGY2AK021l84ACjcxK6xIIjxv20xvE14v26F1j6w1UM28EF7xv wVC0I7IYx2IY6xkF7I0E14v26F4j6r4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7 xvwVC2z280aVCY1x0267AKxVW0oVCq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40E FcxC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr 0_Gr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcVAKI48JMxAIw28IcxkI7VAKI48JMxAq zxv26xkF7I0En4kS14v26r1q6r43MxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrV AFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUtVW8ZwCI c40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267 AKxVWUJVW8JwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Jr0_ Gr1lIxAIcVC2z280aVCY1x0267AKxVWUJVW8JbIYCTnIWIevJa73UjIFyTuYvjxUrR6zUU UUU X-CM-SenderInfo: hfkh02xlgr0w46kxt4xhlfz01xgou0bp/ > I acknowledge the issue (although rare in real world). Some entity will > always have to wait of the offlining. It may be OK in cgroup_kill_sb > (ideally, if this was bound to process context of umount caller, not > sure if that's how kill_sb works). > I slightly dislike the form of an empty lock/unlock -- which makes me > wonder if this is the best solution. > > Let me think more about this... > > Thanks, > Michal Hi Michal, Have you come up with a better solution for this? Would appreciate your thoughts when you have time. Best regards, Ridong