Remove the mem_cgroup member from mm_struct and instead adds an owner.

This approach was suggested by Paul Menage.  The advantage of this approach
is that, once the mm->owner is known, using the subsystem id, the cgroup
can be determined.  It also allows several control groups that are
virtually grouped by mm_struct, to exist independent of the memory
controller i.e., without adding mem_cgroup's for each controller, to
mm_struct.

A new config option CONFIG_MM_OWNER is added and the memory resource
controller selects this config option.

This patch also adds cgroup callbacks to notify subsystems when mm->owner
changes.  The mm_cgroup_changed callback is called with the task_lock() of
the new task held and is called just prior to changing the mm->owner.

I am indebted to Paul Menage for the several reviews of this patchset and
helping me make it lighter and simpler.

This patch was tested on a powerpc box, it was compiled with both the
MM_OWNER config turned on and off.

After the thread group leader exits, it's moved to init_css_state by
cgroup_exit(), thus all future charges from runnings threads would be
redirected to the init_css_set's subsystem.
Signed-off-by: NBalbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Sudhir Kumar <skumar@linux.vnet.ibm.com>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: Hirokazu Takahashi <taka@valinux.co.jp>
Cc: David Rientjes <rientjes@google.com>,
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: NPekka Enberg <penberg@cs.helsinki.fi>
Reviewed-by: NPaul Menage <menage@google.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Introduce a read_seq() helper in cftype, which uses seq_file to print out
lists.  Use it in the devices cgroup.  Also split devices.allow into two
files, so now devices.deny and devices.allow are the ones to use to manipulate
the whitelist, while devices.list outputs the cgroup's current whitelist.
Signed-off-by: NSerge E. Hallyn <serue@us.ibm.com>
Acked-by: NPaul Menage <menage@google.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Now we can run through the hash table instead of running through the
linked-list.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Reviewed-by: NPaul Menage <menage@google.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We are at system boot and there is only 1 cgroup group (i,e, init_css_set), so
we don't need to run through the css_set linked list.  Neither do we need to
run through the task list, since no processes have been created yet.

Also referring to a comment in cgroup.h:

struct css_set
{
	...
	/*
	 * Set of subsystem states, one for each subsystem. This array
	 * is immutable after creation apart from the init_css_set
	 * during subsystem registration (at boot time).
	 */
	struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT];
}
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Reviewed-by: NPaul Menage <menage@google.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When we attach a process to a different cgroup, the css_set linked-list will
be run through to find a suitable existing css_set to use.  This patch
implements a hash table for better performance.

The following benchmarks have been tested:

For N in 1, 5, 10, 50, 100, 500, 1000, create N cgroups with one sleeping
task in each, and then move an additional task through each cgroup in
turn.

Here is a test result:

N	Loop	orig - Time(s)	hash - Time(s)
----------------------------------------------
1	10000	1.201231728	1.196311177
5	2000	1.065743872	1.040566424
10	1000	0.991054735	0.986876440
50	200	0.976554203	0.969608733
100	100	0.998504680	0.969218270
500	20	1.157347764	0.962602963
1000	10	1.619521852	1.085140172
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Reviewed-by: NPaul Menage <menage@google.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Trigger callback can be used to receive a kick-up from the user space.  The
string written is ignored.

The cftype->private is used for multiplexing events.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Acked-by: NPaul Menage <menage@google.com>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is a race between create_proc_entry() and the assignment of file ops.
proc_create() is invented to fix it.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Acked-by: NPaul Menage <menage@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It is called by cgroup_init() and cgroup_init_early() only, which are
annotated with __init.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

These patches add cgroups read_s64 and write_s64 control file methods (the
signed equivalent of read_u64/write_u64) and use them to implement the
cpu.rt_runtime_us control file in the CFS cgroup subsystem.

This patch:

These are the signed equivalents of the read_u64/write_u64 methods
Signed-off-by: NPaul Menage <menage@google.com>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The "releasable" control file provided by the cgroup framework exports the
state of a per-cgroup flag that's related to the notify-on-release feature.
This isn't really generally useful, unless you're trying to debug this
particular feature of cgroups.

This patch moves the "releasable" file to the cgroup_debug subsystem.
Signed-off-by: NPaul Menage <menage@google.com>
Cc: "Li Zefan" <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "YAMAMOTO Takashi" <yamamoto@valinux.co.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Adds a new type of supported control file representation, a map from strings
to u64 values.

Each map entry is printed as a line in a similar format to /proc/vmstat, i.e.
"$key $value\n"
Signed-off-by: NPaul Menage <menage@google.com>
Cc: "Li Zefan" <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "YAMAMOTO Takashi" <yamamoto@valinux.co.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This removes the need for people to remember to pass the -n flag to echo when
writing values to cgroup control files.
Signed-off-by: NPaul Menage <menage@google.com>
Cc: "Li Zefan" <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "YAMAMOTO Takashi" <yamamoto@valinux.co.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Several people have justifiably complained that the "_uint" suffix is
inappropriate for functions that handle u64 values, so this patch just renames
all these functions and their users to have the suffic _u64.

[peterz@infradead.org: build fix]
Signed-off-by: NPaul Menage <menage@google.com>
Cc: "Li Zefan" <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "YAMAMOTO Takashi" <yamamoto@valinux.co.jp>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix a code warning: symbol 'p' shadows an earlier one

This is a reincarnation of Harvey Harrison's patch:
	cpuset: sparse warnings in cpuset.c

Independently, Cliff Wickman moved the affected code,
from kernel/cpuset.c to kernel/cgroup.c, in his patch:
	cpusets: update_cpumask revision
Signed-off-by: NPaul Jackson <pj@sgi.com>
Cc: Harvey Harrison <harvey.harrison@gmail.com>
Cc: Cliff Wickman <cpw@sgi.com>
Acked-by: NPaul Menage <menage@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make the needlessly global cgroup_enable_task_cg_lists() static.
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Acked-by: NDavid Rientjes <rientjes@google.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When I ran a test program to fork mass processes and at the same time
'cat /cgroup/tasks', I got the following oops:

  ------------[ cut here ]------------
  kernel BUG at lib/list_debug.c:72!
  invalid opcode: 0000 [#1] SMP
  Pid: 4178, comm: a.out Not tainted (2.6.25-rc9 #72)
  ...
  Call Trace:
   [<c044a5f9>] ? cgroup_exit+0x55/0x94
   [<c0427acf>] ? do_exit+0x217/0x5ba
   [<c0427ed7>] ? do_group_exit+0.65/0x7c
   [<c0427efd>] ? sys_exit_group+0xf/0x11
   [<c0404842>] ? syscall_call+0x7/0xb
   [<c05e0000>] ? init_cyrix+0x2fa/0x479
  ...
  EIP: [<c04df671>] list_del+0x35/0x53 SS:ESP 0068:ebc7df4
  ---[ end trace caffb7332252612b ]---
  Fixing recursive fault but reboot is needed!

After digging into the code and debugging, I finlly found out a race
situation:

				do_exit()
				  ->cgroup_exit()
				    ->if (!list_empty(&tsk->cg_list))
				        list_del(&tsk->cg_list);

  cgroup_iter_start()
    ->cgroup_enable_task_cg_list()
      ->list_add(&tsk->cg_list, ..);

In this case the list won't be deleted though the process has exited.

We got two bug reports in the past, which seem to be the same bug as
this one:
	http://lkml.org/lkml/2008/3/5/332
	http://lkml.org/lkml/2007/10/17/224

Actually sometimes I got oops on list_del, sometimes oops on list_add.
And I can change my test program a bit to trigger other oops.

The patch has been tested both on x86_32 and x86_64.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Acked-by: NPaul Menage <menage@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Extend the /proc/<pid>/cgroup file to include the appropriate hierarchy ID on
each line.

Currently this ID isn't really needed since a hierarchy can be completely
identified by the set of subsystems bound to it, but this is likely to change
in the near future in order to support stateless subsystems and
merging/rebinding of subsystems.  Getting this change into 2.6.25 reduces the
need for an API change later.
Signed-off-by: NPaul Menage <menage@google.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The effects of cgroup_disable=foo are:

- foo isn't auto-mounted if you mount all cgroups in a single hierarchy
- foo isn't visible as an individually mountable subsystem

As a result there will only ever be one call to foo->create(), at init time;
all processes will stay in this group, and the group will never be mounted on
a visible hierarchy.  Any additional effects (e.g.  not allocating metadata)
are up to the foo subsystem.

This doesn't handle early_init subsystems (their "disabled" bit isn't set be,
but it could easily be extended to do so if any of the early_init systems
wanted it - I think it would just involve some nastier parameter processing
since it would occur before the command-line argument parser had been run.

Hugh said:

  Ballpark figures, I'm trying to get this question out rather than
  processing the exact numbers: CONFIG_CGROUP_MEM_RES_CTLR adds 15% overhead
  to the affected paths, booting with cgroup_disable=memory cuts that back to
  1% overhead (due to slightly bigger struct page).

  I'm no expert on distros, they may have no interest whatever in
  CONFIG_CGROUP_MEM_RES_CTLR=y; and the rest of us can easily build with or
  without it, or apply the cgroup_disable=memory patches.

Unix bench's execl test result on x86_64 was

== just after boot without mounting any cgroup fs.==
mem_cgorup=off : Execl Throughput       43.0     3150.1      732.6
mem_cgroup=on  : Execl Throughput       43.0     2932.6      682.0
==

[lizf@cn.fujitsu.com: fix boot option parsing]
Signed-off-by: NBalbir Singh <balbir@linux.vnet.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Sudhir Kumar <skumar@linux.vnet.ibm.com>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The documentation says the default value of notify_on_release of a child
cgroup is inherited from its parent, which is reasonable, but the
implementation just sets the flag disabled.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Acked-by: NPaul Menage <menage@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Acked-by: NPaul Menage <menage@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The list head res->tasks gets initialized twice in find_css_set().
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Acked-by: NPaul Menage <menage@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Cgroup uses unsigned long for subsys bitops, not unsigned long long.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Acked-by: NPaul Menage <menage@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

opts.release_agent is not kfree()ed in all necessary places.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Acked-by: NPaul Menage <menage@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

fix:
- comments about need_forkexit_callback
- comments about release agent
- typo and comment style, etc.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Acked-by: NPaul Menage <menage@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There's one place that works with task pids - its the "tasks" file in cgroups.
 The read/write handlers assume, that the pid values go to/come from the user
space and thus it is a virtual pid, i.e.  the pid as it is seen from inside a
namespace.

Tune the code accordingly.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: NPaul Menage <menage@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch corrects a situation that occurs when one disables all the cpus in
a cpuset.

Currently, the disabled (cpu-less) cpuset inherits the cpus of its parent,
which is incorrect because it may then overlap its cpu-exclusive sibling.

Tasks of an empty cpuset should be moved to the cpuset which is the parent of
their current cpuset.  Or if the parent cpuset has no cpus, to its parent,
etc.

And the empty cpuset should be released (if it is flagged notify_on_release).

Depends on the cgroup_scan_tasks() function (proposed by David Rientjes) to
iterate through all tasks in the cpu-less cpuset.  We are deliberately
avoiding a walk of the tasklist.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NCliff Wickman <cpw@sgi.com>
Cc: Paul Menage <menage@google.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Provide cgroup_scan_tasks(), which iterates through every task in a cgroup,
calling a test function and a process function for each.  And call the process
function without holding the css_set_lock lock.

The idea is David Rientjes', predicting that such a function will make it much
easier in the future to extend things that require access to each task in a
cgroup without holding the lock,

[akpm@linux-foundation.org: cleanup]
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NCliff Wickman <cpw@sgi.com>
Cc: Paul Menage <menage@google.com>
Cc: Paul Jackson <pj@sgi.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add a handler "pre_destroy" to cgroup_subsys.  It is called before
cgroup_rmdir() checks all subsys's refcnt.

I think this is useful for subsys which have some extra refs even if there
are no tasks in cgroup.  By adding pre_destroy(), the kernel keeps the rule
"destroy() against subsystem is called only when refcnt=0." and allows css
ref to be used by other objects than tasks.
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Kirill Korotaev <dev@sw.ru>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Paul Menage <menage@google.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

cgroup_is_releasable() and notify_on_release() should be static,
not global inline.
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Acked-by: NPaul Menage <menage@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Move the calls to the cgroup subsystem destroy() methods from
cgroup_rmdir() to cgroup_diput().  This allows control file reads and
writes to access their subsystem state without having to be concerned with
locking against cgroup destruction - the control file dentry will keep the
cgroup and its subsystem state objects alive until the file is closed.

The documentation is updated to reflect the changed semantics of destroy();
additionally the locking comments for destroy() and some other methods were
clarified and decrustified.
Signed-off-by: NPaul Menage <menage@google.com>
Cc: Paul Jackson <pj@sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Simplify the space stripping code in cgroup file write.

[akpm@linux-foundation.org: s/BUG_ON/BUILD_BUG_ON/]
Signed-off-by: NPaul Jackson <pj@sgi.com>
Acked-by: NPaul Menage <menage@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Coding style fix - one line conditionals don't get braces.
Signed-off-by: NPaul Jackson <pj@sgi.com>
Acked-by: NPaul Menage <menage@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch removes dead code spotted by the Coverity checker
(look at the "(nbytes >= PATH_MAX)" check).
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Cc: Paul Jackson <pj@sgi.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When I boot with the 'quiet' parameter, I see on the screen:

[    0.000000] Initializing cgroup subsys cpuset
[    0.000000] Initializing cgroup subsys cpu
[   39.036026] Initializing cgroup subsys cpuacct
[   39.036080] Initializing cgroup subsys debug
[   39.036118] Initializing cgroup subsys ns

This patch lowers the priority of those messages, adds a "cgroup: " prefix
to another couple of printks and kills the useless reference to the source
file.
Signed-off-by: NDiego Calleja <diegocg@gmail.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

Replace "cont" with "cgrp" and other misc renaming

This patch finishes some of the names that got missed in the great
"task containers" -> "control groups" rename. Primarily it renames
the local variable "cont" to "cgrp" in a number of places, and renames
the CONT_* enum members to CGRP_*.

This patch is not intended to have any effect on the generated code;
the output of "objdump -d kernel/cgroup.o" is unchanged.
Signed-off-by: NPaul Menage <menage@google.com>
Acked-by: NPaul Jackson <pj@sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There are two places that do so - the cgroups subsystem and the autofs
code.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Cc: Ian Kent <raven@themaw.net>
Cc: Paul Menage <menage@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch is inspired by the discussion at
http://lkml.org/lkml/2007/4/11/187 and implements per cgroup statistics
as suggested by Andrew Morton in http://lkml.org/lkml/2007/4/11/263.  The
patch is on top of 2.6.21-mm1 with Paul's cgroups v9 patches (forward
ported)

This patch implements per cgroup statistics infrastructure and re-uses
code from the taskstats interface.  A new set of cgroup operations are
registered with commands and attributes.  It should be very easy to
*extend* per cgroup statistics, by adding members to the cgroupstats
structure.

The current model for cgroupstats is a pull, a push model (to post
statistics on interesting events), should be very easy to add.  Currently
user space requests for statistics by passing the cgroup file
descriptor.  Statistics about the state of all the tasks in the cgroup
is returned to user space.

TODO's/NOTE:

This patch provides an infrastructure for implementing cgroup statistics.
Based on the needs of each controller, we can incrementally add more statistics,
event based support for notification of statistics, accumulation of taskstats
into cgroup statistics in the future.

Sample output

# ./cgroupstats -C /cgroup/a
sleeping 2, blocked 0, running 1, stopped 0, uninterruptible 0

# ./cgroupstats -C /cgroup/
sleeping 154, blocked 0, running 0, stopped 0, uninterruptible 0

If the approach looks good, I'll enhance and post the user space utility for
the same

Feedback, comments, test results are always welcome!

[akpm@linux-foundation.org: build fix]
Signed-off-by: NBalbir Singh <balbir@linux.vnet.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add the following files to the cgroup filesystem:

notify_on_release - configures/reports whether the cgroup subsystem should
attempt to run a release script when this cgroup becomes unused

release_agent - configures/reports the release agent to be used for this
hierarchy (top level in each hierarchy only)

releasable - reports whether this cgroup would have been auto-released if
notify_on_release was true and a release agent was configured (mainly useful
for debugging)

To avoid locking issues, invoking the userspace release agent is done via a
workqueue task; cgroups that need to have their release agents invoked by
the workqueue task are linked on to a list.

[pj@sgi.com: Need to include kmod.h]
Signed-off-by: NPaul Menage <menage@google.com>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: NPaul Jackson <pj@sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>