From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 97FA7CA5FCF for ; Thu, 1 Oct 2026 17:56:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:MIME-Version:References:In-Reply-To:Subject:Cc:To:From: Message-ID:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Z8MODFbKIDDrvoDt04zQa5qco4SxCWWHkK7Oz4Y0sy4=; b=C6OvVN0gveQEQrAmHmONsAusBW 8+pJpe5EsisxnQY6/7g9FfcVn+dmY+HjaHsatF/XEvlbkCn2P6LhrS/Yso2AsD8KuvbQxwsnwPQce 5rRuN0JQA5bTW8opB6YJQ8BA77+KKpNNjulGbMNSIjr9mgUiNzqOlIE0E2Y0rMwDrtq112LXdZOut vLcu/uB4pdIEGSOge5EBDYS8u5Es98LV69klxV5ywBH0cYW1ixve/Knn3OeEAOAFGPuYVbNCFxxPG 99JZUcDlySKELpdI+Msa98ZAg9V5mdR3WClmexUpaZLYjqadt1IhpvcPEoaN/EzPYkVv1hkO7MdrZ k469IKpg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xCL1D-00000009vQO-3PCl; Thu, 01 Oct 2026 17:56:31 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1xCL1B-00000009vPu-3Snt for linux-nvme@lists.infradead.org; Thu, 01 Oct 2026 17:56:29 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 2F65340920; Thu, 1 Oct 2026 17:56:29 +0000 (UTC) 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org 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