From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 F0D3039B497; Wed, 9 Sep 2026 18:59:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788980400; cv=none; b=H/j4RXMhK1rGSHteGrA+Lh2ur6Hl8dRPyXLyyVXj+f0uN824sBxJ9bzabvNPjQWrPvPptg9tthB/CGoqOXhBuXIW34TiVc9ViAL73oAZQlptIMhbTrNApqAOLXLt3d9cunWDw0Ki95xS0qrvnXCNb5mkffyz+450XfIvnLq7brA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788980400; c=relaxed/simple; bh=XJKJ7anL7hXoTXFizwsDHiJ3oit7/vRl3YUppSqzpB8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=YwTHijIzp/g6pUEXZlMOyiSFHt8/EtKa63xigxi5oz/t719dnMOs9IRbMlUTdS1fB7KSn+VdNoOmwPZ7YzRty9gA944xBOv+sNsB/nmNO0uVrXyIb9b1V+WbRQXJGFiGSLUO3XY6xNvm9PWoAOCnWiiIsT/WL5rSVjY9kK4GrnM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=M1Q+eEm/; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="M1Q+eEm/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A59211F000FF; Wed, 9 Sep 2026 18:59:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788980398; bh=FUYw9ieBaMi9B5CXc3nNfGkqutWFJDcR4LezWBU8ycc=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=M1Q+eEm/pjRG9p35tZ2tq7sBCyQ7YjpNO0MNx3uV5+xK8ugC2Vjj1A7/gdJtdv5iT gCyuHYYLuttZv8t0oUi5lzZi8SDVrn6BBjnLycPCL20X/3kCdNS4rW5zRTBkExKKfI yeClu/L6NNoswf+Im2oOinEWfvFuOtXnqrAgaNC6NH3XPKG71KaKTCa6/S6S4iPTEK Q9+h77zkGBXiA1BYxFGPpCBcz9GJNyLD1WAWqYmSp1Z0THX+cJr40XifoGRFqOKTFr Li3VyrooVn/0XoBd31V1CqSzGkknLmVIqO36kzgOkjWj72QdJ40VItqyewg4rw1ijf QASdi5vXKxwwQ== Date: Wed, 9 Sep 2026 08:59:57 -1000 From: Tejun Heo To: Junnan Zhang 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 Message-ID: References: <20260909084619.91579-1-zhangjn_dev@163.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260909084619.91579-1-zhangjn_dev@163.com> Hello, On Wed, Sep 09, 2026 at 04:46:19PM +0800, Junnan Zhang wrote: > 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? The problem is that the root cause isn't sufficiently established. It's just difficult to believe cleaning up these lists would take longer than 120s in itself. Maybe there were other contributing factors - e.g. another saturating per-cpu work item that was preventing the execution of the pidlist work item, high memory pressure stalling worker creation, or just severe CPU contention from bw control or whatnot. Without the root cause convincingly established, this can't be a "minimal fix". This can be a proactive behavior improvement, but that's not something we want to do for cgroup1 code base at this point. Not because we hate people on cgroup1 but because they're the legacy users on legacy code base. Nobody is actively working on it and no leading edge testing and adoption covers it. Any change carries risk of breakage and a change like this can lead to really subtle problems that can take a long time to diagnose especially with slow-moving long-tail userbase. So, yes, I'll take minimal fixes that address real problems (subject to risk vs. benefit balance of course), but you haven't established that yet. Thanks. -- tejun