From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161081Ab2COQ5M (ORCPT ); Thu, 15 Mar 2012 12:57:12 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:43137 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161050Ab2COQ5C (ORCPT ); Thu, 15 Mar 2012 12:57:02 -0400 Date: Thu, 15 Mar 2012 09:56:55 -0700 From: Tejun Heo To: Li Zefan , containers@lists.linux-foundation.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Frederic Weisbecker , Lennart Poettering Subject: [PATCH] cgroup: deprecate remount option changes mount option Message-ID: <20120315165655.GD32137@google.com> References: <20120314215228.GI7349@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120314215228.GI7349@google.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch marks the following features for deprecation. * Rebinding subsys by remount: Never reached useful state - only works on empty hierarchies. * release_agent update by remount: release_agent itself will be replaced with conventional fsnotify notification. v2: Lennart pointed out that "name=" is necessary for mounts w/o any controller attached. Drop "name=" deprecation. Signed-off-by: Tejun Heo Cc: Li Zefan Cc: Lennart Poettering --- Documentation/feature-removal-schedule.txt | 10 ++++++++++ kernel/cgroup.c | 5 +++++ 2 files changed, 15 insertions(+) Index: work/Documentation/feature-removal-schedule.txt =================================================================== --- work.orig/Documentation/feature-removal-schedule.txt +++ work/Documentation/feature-removal-schedule.txt @@ -510,3 +510,13 @@ Why: The pci_scan_bus_parented() interfa convert to using pci_scan_root_bus() so they can supply a list of bus resources when the bus is created. Who: Bjorn Helgaas + +---------------------------- + +What: cgroup option updates via remount +When: March 2013 +Why: Remount currently allows changing bound subsystems and + release_agent. Rebinding is hardly useful as it only works + when the hierarchy is empty and release_agent itself should be + replaced with conventional fsnotify. +Who: Tejun Heo Index: work/kernel/cgroup.c =================================================================== --- work.orig/kernel/cgroup.c +++ work/kernel/cgroup.c @@ -1294,6 +1294,11 @@ static int cgroup_remount(struct super_b if (ret) goto out_unlock; + /* See feature-removal-schedule.txt */ + if (opts.subsys_bits != root->actual_subsys_bits || opts.release_agent) + pr_warning("cgroup: option changes via remount are deprecated (pid=%d comm=%s)\n", + task_tgid_nr(current), current->comm); + /* Don't allow flags or name to change at remount */ if (opts.flags != root->flags || (opts.name && strcmp(opts.name, root->name))) {