linux-stable.git/include/linux/cgroup.h, branch linux-2.6.25.y

cgroups: add cgroup support for enabling controllers at boot time

2008-04-04T21:46:26+00:00

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: Balbir Singh 
Cc: Paul Menage 
Cc: Balbir Singh 
Cc: Pavel Emelyanov 
Cc: KAMEZAWA Hiroyuki 
Cc: Hugh Dickins 
Cc: Sudhir Kumar 
Cc: YAMAMOTO Takashi 
Cc: David Rientjes 
Signed-off-by: Li Zefan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroup: clean up cgroup.h

2008-02-24T01:13:24+00:00

- replace old name 'cont' with 'cgrp' (Paul Menage did this cleanup for
  cgroup.c in commit bd89aabc6761de1c35b154fe6f914a445d301510)
- remove a duplicate declaration of cgroup_path()

Signed-off-by: Li Zefan 
Acked-by: Paul Menage 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroup: fix comments

2008-02-24T01:13:24+00:00

fix:
- comments about need_forkexit_callback
- comments about release agent
- typo and comment style, etc.

Signed-off-by: Li Zefan 
Acked-by: Paul Menage 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

hotplug cpu: move tasks in empty cpusets to parent

2008-02-07T16:42:22+00:00

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: Cliff Wickman 
Cc: Paul Menage 
Cc: Paul Jackson 
Cc: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroups: mechanism to process each task in a cgroup

2008-02-07T16:42:22+00:00

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: Cliff Wickman 
Cc: Paul Menage 
Cc: Paul Jackson 
Acked-by: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memory cgroup enhancements: add- pre_destroy() handler

2008-02-07T16:42:20+00:00

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: KAMEZAWA Hiroyuki 
Cc: "Eric W. Biederman" 
Cc: Balbir Singh 
Cc: David Rientjes 
Cc: Herbert Poetzl 
Cc: Kirill Korotaev 
Cc: Nick Piggin 
Cc: Paul Menage 
Cc: Pavel Emelianov 
Cc: Peter Zijlstra 
Cc: Vaidyanathan Srinivasan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Add cgroupstats

2007-10-19T18:53:36+00:00

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: Balbir Singh 
Cc: Paul Menage 
Cc: Jay Lan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Task Control Groups: automatic userspace notification of idle cgroups

2007-10-19T18:53:36+00:00

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: Paul Menage 
Cc: Serge E. Hallyn 
Cc: "Eric W. Biederman" 
Cc: Dave Hansen 
Cc: Balbir Singh 
Cc: Paul Jackson 
Cc: Kirill Korotaev 
Cc: Herbert Poetzl 
Cc: Srivatsa Vaddagiri 
Cc: Cedric Le Goater 
Signed-off-by: Paul Jackson 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Task Control Groups: shared cgroup subsystem group arrays

2007-10-19T18:53:36+00:00

Replace the struct css_set embedded in task_struct with a pointer; all tasks
that have the same set of memberships across all hierarchies will share a
css_set object, and will be linked via their css_sets field to the "tasks"
list_head in the css_set.

Assuming that many tasks share the same cgroup assignments, this reduces
overall space usage and keeps the size of the task_struct down (three pointers
added to task_struct compared to a non-cgroups kernel, no matter how many
subsystems are registered).

[akpm@linux-foundation.org: fix a printk]
[akpm@linux-foundation.org: build fix]
Signed-off-by: Paul Menage 
Cc: Serge E. Hallyn 
Cc: "Eric W. Biederman" 
Cc: Dave Hansen 
Cc: Balbir Singh 
Cc: Paul Jackson 
Cc: Kirill Korotaev 
Cc: Herbert Poetzl 
Cc: Srivatsa Vaddagiri 
Cc: Cedric Le Goater 
Cc: Serge E. Hallyn 
Cc: "Eric W. Biederman" 
Cc: Dave Hansen 
Cc: Balbir Singh 
Cc: Paul Jackson 
Cc: Kirill Korotaev 
Cc: Herbert Poetzl 
Cc: Srivatsa Vaddagiri 
Cc: Cedric Le Goater 
Cc: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Task Control Groups: add procfs interface

2007-10-19T18:53:36+00:00

Add:

/proc/cgroups - general system info

/proc/*/cgroup - per-task cgroup membership info

[a.p.zijlstra@chello.nl: cgroups: bdi init hooks]
Signed-off-by: Paul Menage 
Cc: Serge E. Hallyn 
Cc: "Eric W. Biederman" 
Cc: Dave Hansen 
Cc: Balbir Singh 
Cc: Paul Jackson 
Cc: Kirill Korotaev 
Cc: Herbert Poetzl 
Cc: Srivatsa Vaddagiri 
Cc: Cedric Le Goater 
Signed-off-by: Peter Zijlstra 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds