Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753351Ab0G3X52 (ORCPT ); Fri, 30 Jul 2010 19:57:28 -0400 Received: from SMTP.ANDREW.CMU.EDU ([128.2.11.96]:54572 "EHLO smtp.andrew.cmu.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751324Ab0G3X50 (ORCPT ); Fri, 30 Jul 2010 19:57:26 -0400 Date: Fri, 30 Jul 2010 19:56:49 -0400 From: Ben Blum To: linux-kernel@vger.kernel.org, containers@lists.linux-foundation.org Cc: akpm@linux-foundation.org, bblum@andrew.cmu.edu, ebiederm@xmission.com, lizf@cn.fujitsu.com, matthltc@us.ibm.com, menage@google.com, oleg@redhat.com Subject: [PATCH v4 0/2] cgroups: implement moving a threadgroup's threads atomically with cgroup.procs Message-ID: <20100730235649.GA22644@ghc17.ghc.andrew.cmu.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.20 (2009-06-14) X-PMX-Version: 5.5.9.388399, Antispam-Engine: 2.7.2.376379, Antispam-Data: 2010.4.9.4220 X-SMTP-Spam-Clean: 8% ( BODY_SIZE_1700_1799 0, BODY_SIZE_2000_LESS 0, BODY_SIZE_5000_LESS 0, BODY_SIZE_7000_LESS 0, TO_NO_NAME 0, __CD 0, __CP_URI_IN_BODY 0, __CT 0, __CT_TEXT_PLAIN 0, __HAS_MSGID 0, __MIME_TEXT_ONLY 0, __MIME_VERSION 0, __SANE_MSGID 0, __TO_MALFORMED_2 0, __URI_NO_MAILTO 0, __URI_NO_WWW 0, __USER_AGENT 0) X-SMTP-Spam-Score: 8% Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1946 Lines: 50 This patch series is a revision of http://lkml.org/lkml/2010/6/25/11 . This patch series implements a write function for the 'cgroup.procs' per-cgroup file, which enables atomic movement of multithreaded applications between cgroups. Writing the thread-ID of any thread in a threadgroup to a cgroup's procs file causes all threads in the group to be moved to that cgroup safely with respect to threads forking/exiting. (Possible usage scenario: If running a multithreaded build system that sucks up system resources, this lets you restrict it all at once into a new cgroup to keep it under control.) Example: Suppose pid 31337 clones new threads 31338 and 31339. # cat /dev/cgroup/tasks ... 31337 31338 31339 # mkdir /dev/cgroup/foo # echo 31337 > /dev/cgroup/foo/cgroup.procs # cat /dev/cgroup/foo/tasks 31337 31338 31339 A new lock, called threadgroup_fork_lock and living in signal_struct, is introduced to ensure atomicity when moving threads between cgroups. It's taken for writing during the operation, and taking for reading in fork() around the calls to cgroup_fork() and cgroup_post_fork(). I put calls to down_read/up_read directly in copy_process(), since new inline functions seemed like overkill. -- Ben --- Documentation/cgroups/cgroups.txt | 13 - include/linux/init_task.h | 9 include/linux/sched.h | 10 kernel/cgroup.c | 426 +++++++++++++++++++++++++++++++++----- kernel/cgroup_freezer.c | 4 kernel/cpuset.c | 4 kernel/fork.c | 16 + kernel/ns_cgroup.c | 4 kernel/sched.c | 4 9 files changed, 440 insertions(+), 50 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/