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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 18050C77B7C for ; Fri, 5 May 2023 18:17:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233189AbjEESRS (ORCPT ); Fri, 5 May 2023 14:17:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41376 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231611AbjEESRN (ORCPT ); Fri, 5 May 2023 14:17:13 -0400 Received: from mail-pf1-x432.google.com (mail-pf1-x432.google.com [IPv6:2607:f8b0:4864:20::432]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0550F13867; Fri, 5 May 2023 11:17:13 -0700 (PDT) Received: by mail-pf1-x432.google.com with SMTP id d2e1a72fcca58-6439e6f5a33so728448b3a.2; Fri, 05 May 2023 11:17:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1683310632; x=1685902632; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:sender :from:to:cc:subject:date:message-id:reply-to; bh=hQHYPlEOPVX2QdptzuBIqeiKD9YF9ynx2rWgtCguSI8=; b=GATLJaLXKGT4UkAZCszdVSnAxGdXekLCDA78/LXvLjMCrf0gMpGYAkPJRHrMm0efTx 2AM0YfRkyInaP8G4IZNRe8myyYOaXG5+TuMqRchxZEwR9sTQCmwEF4avYnvLkXRb0lXu ZshUyzcCLOseMwGIi5mw2rXGsskJBuqqTZRnN6UkR7zZub+q9aiBuh3FpMqLNkZUP7KI BTdvqQlkE1CsXOaAfreOSuXojjPs3gqE52ZkWkmQuFz8wYaw1ctggUDUAoX3BGqn+nzM IFKIvUYSxV1GPI2RQJ0y+DCJy+DHy7Y/zHqZ2b9RsvjJufRA8dGuYr0hlB18YDukodzy N2XA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683310632; x=1685902632; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:sender :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=hQHYPlEOPVX2QdptzuBIqeiKD9YF9ynx2rWgtCguSI8=; b=Y8WQ6uIupl/GCdeFck/mdveFQtwiDNAYNpagkw5IPkE5fDuGM1xiwwFpAj6r8amBBh rz3hiFOm6iUGJFv7HYEqkf7nFu244avmRjknWgjlc61KX0yRFcDQRCMImN6tZisMZn/c Q6eVtg17VZTQQ77C/hNR9JnuD+0SdEV24AFYbPuACBnypJJ+mbuSLX+5ca7vEjGs6xqP 3VnPTEnXWpTm9le73ADYkIK3WXsfvg67J+jjMeK9etHyuCMPbXcMXorhXXVH0hC3+3Xk YsggXim18XIamEVxEYwECBfA1fD6mREJ58DJodgWP2QTVSyrm1Z4CGjMvZB4mydbKUMr i8Fw== X-Gm-Message-State: AC+VfDxJ5Qx1e7OAkQJmGKT6QJ8IOpg4XSJVOoMUkMkB+OplybKDqBin USMca4BH18sepYfzFSBGtks= X-Google-Smtp-Source: ACHHUZ7QKd0LACqSPErWFC498KThy/cj79nXPyY5L/RHExPh/Le5xmdhFDDNN/T5EkzTJQvPbKOtNw== X-Received: by 2002:a05:6a20:d687:b0:ef:a696:993a with SMTP id it7-20020a056a20d68700b000efa696993amr2541812pzb.22.1683310632188; Fri, 05 May 2023 11:17:12 -0700 (PDT) Received: from localhost (2603-800c-1a02-1bae-a7fa-157f-969a-4cde.res6.spectrum.com. [2603:800c:1a02:1bae:a7fa:157f:969a:4cde]) by smtp.gmail.com with ESMTPSA id y14-20020aa7854e000000b0063b6cccd5dfsm1912910pfn.195.2023.05.05.11.17.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 05 May 2023 11:17:11 -0700 (PDT) Sender: Tejun Heo Date: Fri, 5 May 2023 08:17:10 -1000 From: Tejun Heo To: Michal =?iso-8859-1?Q?Koutn=FD?= Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Alexander Viro , Christian Brauner , Zefan Li , Johannes Weiner , Dave Chinner , Rik van Riel , Jiri Wiesner Subject: Re: [RFC PATCH 3/3] cgroup: Do not take css_set_lock in cgroup_show_path Message-ID: References: <20230502133847.14570-1-mkoutny@suse.com> <20230502133847.14570-4-mkoutny@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Fri, May 05, 2023 at 07:32:40PM +0200, Michal Koutný wrote: > On Fri, May 05, 2023 at 05:45:58AM -1000, Tejun Heo wrote: > > > There are three relevant nodes for each cgroupfs entry: > > > > > > R ... cgroup hierarchy root > > > M ... mount root > > > C ... reader's cgroup NS root > > > > > > mountinfo is supposed to show path from C to M. > > > > At least for cgroup2, the path from C to M isn't gonna change once NS is > > established, right? > > Right. Although, the argument about M (when C above M or when C and M in > different subtrees) implicitly relies on the namespace_sem. I don't follow. Can you please elaborate a bit more? Thanks. -- tejun