From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from m16.mail.163.com (m16.mail.163.com [220.197.31.2]) (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 442B439A07E; Wed, 9 Sep 2026 08:47:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.31.2 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788943631; cv=none; b=lSKcLDXQhHxfWYPG987cxtLPfrn4ec97cEjSspD8AtA7MAhbdpO7foIEQqxjR1YgigimgjQCV3C2D+k5EyzXCHnBHJ9veWjvTLbfZ61EwW1ZFfUNSjyRIjZ/f1ndhd89tV2CE7FgDrWHiPYaq15B2S5amc9ZJewQRoew+iI2BZc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788943631; c=relaxed/simple; bh=8D/Jrs3FJYLJaC+B4zEVEdw2IHnsrFplQX0t1gVYytk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=luc+dUqn41NgVak0PBSyokRLOkvUnSbCeDnj7Uzvii2ALg/fUIRmfKlgho60lRWONN1+eR4fG2OyLyWhCq9yTY7vptF3v2S9Pjp7WEQpEgkLw8tiHB4SMw8c8vAg780AIrowT2hzA6yW9NRnzIhzlTdhh43eLwvUAhVDFxACsuE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=jvPxSGq+; arc=none smtp.client-ip=220.197.31.2 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="jvPxSGq+" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:To:Subject:Date:Message-ID:MIME-Version; bh=8D /Jrs3FJYLJaC+B4zEVEdw2IHnsrFplQX0t1gVYytk=; b=jvPxSGq+7E+CiSUcLE RtA3tgFqamq1+PIGIWxS+o3CSi7apdeRfX2UqujYCAsFGFPZl25/U/lhk2rFa9gv W+Qg/2jhiNJcxAgW+m2be+Tg4Lkwmrqm+ztkgnuoyXq2hXKt3MjHnLpFY9qCXzNt 2MPsRD/05lYmeHSgWt48kw0yo= Received: from sky.localdomain (unknown []) by gzga-smtp-mtada-g1-2 (Coremail) with SMTP id _____wDnmT7dHKFqcEd0Bg--.51566S2; Wed, 09 Sep 2026 16:46:21 +0800 (CST) From: Junnan Zhang To: zhangjn_dev@163.com, Tejun Heo Cc: Michal Koutny , Johannes Weiner , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Ridong Chen , Shouxin Sun Subject: Re: [PATCH v3] cgroup: avoid flushing global workqueue in cgroup1_pidlist_destroy_all Date: Wed, 9 Sep 2026 16:46:19 +0800 Message-ID: <20260909084619.91579-1-zhangjn_dev@163.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:_____wDnmT7dHKFqcEd0Bg--.51566S2 X-Coremail-Antispam: 1Uf129KBjvdXoWruFyUWr1fCFy3Gry5Wr17Jrb_yoWDXwc_uw 10vw4vkw4fKr4kurZ2gF98uan5WrWF9w1xZrWxJrW3t340yrs0vFs0ga4SvFn7Ka97JF98 Gas0qF1akw12gjkaLaAFLSUrUUUUjb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUvcSsGvfC2KfnxnUUI43ZEXa7VUU3ku5UUUUU== X-CM-SenderInfo: x2kd0wxmqbvvry6rljoofrz/xtbCxR1B1mqhHN126AAA3b Hi Tejun, Michal, > I'd rather not touch them at all and eventually retire the whole v1 > interface. Understood, and I have no objection to Michal's approach as the long-term direction -- routing v1 reads through css_task_iter removes the pidlist machinery altogether, including the destroy workqueue behind this hang. May I ask for some guidance on the near term, though? cgroup v1 is still the default on widely deployed enterprise distros and will likely remain in production use for years to come, and this hung task was observed on a production Kubernetes node. This patch (v3) is a pure maintenance fix: it changes no user-visible behavior, adds no interface, and is stable-backportable. It would also remain relevant for the cgroup_v1_sorted=true path if Michal's change lands. Would you consider taking it as a minimal fix? Or, if the consensus is to leave v1 completely untouched, what would be the recommended course for production systems that keep hitting this? Thanks, Junnan