cgroup: remove the ns_cgroup
authorDaniel Lezcano <daniel.lezcano@free.fr>
Thu, 26 May 2011 23:25:23 +0000 (16:25 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 27 May 2011 00:12:34 +0000 (17:12 -0700)
commita77aea92010acf54ad785047234418d5d68772e2
treec7cb57b62fd02bee2baceb79251923f7caec6139
parentd846687d7f84e45f23ecf3846dbb43312a1206dd
cgroup: remove the ns_cgroup

The ns_cgroup is an annoying cgroup at the namespace / cgroup frontier and
leads to some problems:

  * cgroup creation is out-of-control
  * cgroup name can conflict when pids are looping
  * it is not possible to have a single process handling a lot of
    namespaces without falling in a exponential creation time
  * we may want to create a namespace without creating a cgroup

  The ns_cgroup was replaced by a compatibility flag 'clone_children',
  where a newly created cgroup will copy the parent cgroup values.
  The userspace has to manually create a cgroup and add a task to
  the 'tasks' file.

This patch removes the ns_cgroup as suggested in the following thread:

https://lists.linux-foundation.org/pipermail/containers/2009-June/018616.html

The 'cgroup_clone' function is removed because it is no longer used.

This is a userspace-visible change.  Commit 45531757b45c ("cgroup: notify
ns_cgroup deprecated") (merged into 2.6.27) caused the kernel to emit a
printk warning users that the feature is planned for removal.  Since that
time we have heard from XXX users who were affected by this.

Signed-off-by: Daniel Lezcano <daniel.lezcano@free.fr>
Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Jamal Hadi Salim <hadi@cyberus.ca>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Acked-by: Matt Helsley <matthltc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
22 files changed:
Documentation/cgroups/cgroups.txt
arch/mips/configs/bcm47xx_defconfig
arch/mn10300/configs/asb2364_defconfig
arch/powerpc/configs/ppc6xx_defconfig
arch/powerpc/configs/pseries_defconfig
arch/sh/configs/apsh4ad0a_defconfig
arch/sh/configs/sdk7786_defconfig
arch/sh/configs/se7206_defconfig
arch/sh/configs/shx3_defconfig
arch/sh/configs/urquell_defconfig
arch/x86/configs/i386_defconfig
arch/x86/configs/x86_64_defconfig
include/linux/cgroup.h
include/linux/cgroup_subsys.h
include/linux/nsproxy.h
init/Kconfig
kernel/Makefile
kernel/cgroup.c
kernel/cpuset.c
kernel/fork.c
kernel/ns_cgroup.c [deleted file]
kernel/nsproxy.c