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 0DB5251FCC0; Thu, 1 Oct 2026 17:56:33 +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=1790877399; cv=none; b=gxhYgB0/VBsjeyenqKebRXPIVqW0FdMoXPdQVgL3ntfn7jlhhVAC28Ub3AinNGqU3FzvD6nLF1oSaF1DcbsMWdj/4PdBv694woc1SG/2RcQTp4VVwBbFu3ghAWgGxZnWVejwOSN+WDtiQjRDyeQdMzC90FkDUZvXtMAoyGFSe6Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790877399; c=relaxed/simple; bh=Z8MODFbKIDDrvoDt04zQa5qco4SxCWWHkK7Oz4Y0sy4=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=dBKAOXQcw+/uRztJ1enTsBVw2g1E3Kyk9/MQxUmBE7SKKpOR5w1+HgH9fFJ7YJQqBRrNEOUGqYb8oPhqez5AKJX76cITk+d2tJj9z4e8cgaxEqurvDyZbZJuGyQUq+z/Op9JpiHiR1Wq52U9LniGC22+NvDD4Q5EBge4JwC+Qo8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZUcRCyG9; 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="ZUcRCyG9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DD3171F000FF; Thu, 1 Oct 2026 17:56:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790877389; bh=Z8MODFbKIDDrvoDt04zQa5qco4SxCWWHkK7Oz4Y0sy4=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=ZUcRCyG91qi5u6jehSUNqqPIM4UU5FK+Oy57uQATRBt4BETrQpfEUmR28+n+8nN9Z aZnEzP8BKrZQUXXCGKbwnn+UeJXNIlNWwg3FcHn0Has4Uqo8lQi65BkrL0DeFsTDKD 2UTB+9UY2XQU3tPy7BNih96V5Isbz5+K1xkV00VnpSoRABFRZDJB8Tz9LxT/8PfOlG GT8L+SL2Th/STCxC4cfWOQubb9dQE90UmycrXO2pqMpsjbLWgIVrVVZq9UNtdPo9NM ywIiQjm6vxtT8h9ji6ghGILeM6jfBON2FiN5qaXSc5vQgcUIPELfoI/NV9LRsTAPQK w0pb+XHxyyM9A== Date: Thu, 01 Oct 2026 07:56:28 -1000 Message-ID: From: Tejun Heo To: Peng Yu Cc: Christoph Hellwig , Sagi Grimberg , Chaitanya Kulkarni , Johannes Weiner , =?UTF-8?Q?Michal_Koutn=C3=BD?= , Josef Bacik , Jens Axboe , Maurizio Lombardi , cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v7 1/2] cgroup: track the effective css in each cgroup In-Reply-To: <20260929232411.101087-2-yupeng0921@gmail.com> References: <20260929232411.101087-1-yupeng0921@gmail.com> <20260929232411.101087-2-yupeng0921@gmail.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-Transfer-Encoding: 7bit On Tue, Sep 29, 2026 at 04:24:10PM -0700, Peng Yu wrote: > cgroup_e_css() and cgroup_get_e_css() find the effective css by walking > up the hierarchy until they reach a cgroup that has the subsystem > enabled. Per-I/O users such as nvmet need this lookup to be O(1). > > Track the effective css in each cgroup and make cgroup_e_css() and > cgroup_get_e_css() use it. When a css is brought online or offline, > update the effective css of its cgroup and of all descendants. Applied to cgroup/for-7.4 with the subject capitalized. Thanks. -- tejun