linux.git/Documentation/cgroups/cgroups.txt, branch v2.6.34

cgroups: fix procs documentation

2010-04-24T18:31:25+00:00

Writing to cgroup.procs is not supported now.

Signed-off-by: KAMEZAWA Hiroyuki 
Acked-by: Li Zefan 
Cc: Ben Blum 
Cc: Paul Menage 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroup: implement eventfd-based generic API for notifications

2010-03-12T23:52:37+00:00

This patchset introduces eventfd-based API for notifications in cgroups
and implements memory notifications on top of it.

It uses statistics in memory controler to track memory usage.

Output of time(1) on building kernel on tmpfs:

Root cgroup before changes:
	make -j2  506.37 user 60.93s system 193% cpu 4:52.77 total
Non-root cgroup before changes:
	make -j2  507.14 user 62.66s system 193% cpu 4:54.74 total
Root cgroup after changes (0 thresholds):
	make -j2  507.13 user 62.20s system 193% cpu 4:53.55 total
Non-root cgroup after changes (0 thresholds):
	make -j2  507.70 user 64.20s system 193% cpu 4:55.70 total
Root cgroup after changes (1 thresholds, never crossed):
	make -j2  506.97 user 62.20s system 193% cpu 4:53.90 total
Non-root cgroup after changes (1 thresholds, never crossed):
	make -j2  507.55 user 64.08s system 193% cpu 4:55.63 total

This patch:

Introduce the write-only file "cgroup.event_control" in every cgroup.

To register new notification handler you need:
- create an eventfd;
- open a control file to be monitored. Callbacks register_event() and
  unregister_event() must be defined for the control file;
- write "  " to cgroup.event_control.
  Interpretation of args is defined by control file implementation;

eventfd will be woken up by control file implementation or when the
cgroup is removed.

To unregister notification handler just close eventfd.

If you need notification functionality for a control file you have to
implement callbacks register_event() and unregister_event() in the
struct cftype.

[kamezawa.hiroyu@jp.fujitsu.com: Kconfig fix]
Signed-off-by: Kirill A. Shutemov 
Reviewed-by: KAMEZAWA Hiroyuki 
Paul Menage 
Cc: Li Zefan 
Cc: Balbir Singh 
Cc: Pavel Emelyanov 
Cc: Dan Malek 
Cc: Vladislav Buzov 
Cc: Daisuke Nishimura 
Cc: Alexander Shishkin 
Cc: Davide Libenzi 
Signed-off-by: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroups: fix CONTENTS in cgroups documentation

2010-03-12T23:52:36+00:00

Add a forgotten item into CONTENTS.

Signed-off-by: Kirill A. Shutemov 
Acked-by: Paul Menage 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroups: subsystem module unloading

2010-03-12T23:52:36+00:00

Provides support for unloading modular subsystems.

This patch adds a new function cgroup_unload_subsys which is to be used
for removing a loaded subsystem during module deletion.  Reference
counting of the subsystems' modules is moved from once (at load time) to
once per attached hierarchy (in parse_cgroupfs_options and
rebind_subsystems) (i.e., 0 or 1).

Signed-off-by: Ben Blum 
Acked-by: Li Zefan 
Cc: Paul Menage 
Cc: "David S. Miller" 
Cc: KAMEZAWA Hiroyuki 
Cc: Lai Jiangshan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroups: subsystem module loading interface

2010-03-12T23:52:36+00:00

Add interface between cgroups subsystem management and module loading

This patch implements rudimentary module-loading support for cgroups -
namely, a cgroup_load_subsys (similar to cgroup_init_subsys) for use as a
module initcall, and a struct module pointer in struct cgroup_subsys.

Several functions that might be wanted by modules have had EXPORT_SYMBOL
added to them, but it's unclear exactly which functions want it and which
won't.

Signed-off-by: Ben Blum 
Acked-by: Li Zefan 
Cc: Paul Menage 
Cc: "David S. Miller" 
Cc: KAMEZAWA Hiroyuki 
Cc: Lai Jiangshan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroup: introduce cancel_attach()

2010-03-12T23:52:35+00:00

Add cancel_attach() operation to struct cgroup_subsys.  cancel_attach()
can be used when can_attach() operation prepares something for the subsys,
but we should rollback what can_attach() operation has prepared if attach
task fails after we've succeeded in can_attach().

Signed-off-by: Daisuke Nishimura 
Acked-by: Li Zefan 
Reviewed-by: Paul Menage 
Cc: Balbir Singh 
Acked-by: KAMEZAWA Hiroyuki 
Cc: Daisuke Nishimura 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroups: update documentation of cgroups tasks and procs files

2009-10-08T14:36:39+00:00

Update documentation of cgroups tasks and procs files

Document the cgroup.procs file.

Clarify the semantics of the cgroup.procs and tasks files.  Although the
current cgroup.procs interface returns a sorted and uniqified list of
pids, potential future performance enhancements could result in those
properties being removed - explicitly document this aspect of the API.

There are no existing users of cgroup.procs, so compatibility isn't an
issue.  There are users of the "tasks" file, but none that would appear to
break in the event of the sorted property being broken.  The standard
"libcpuset" explicitly sorts the results of reading from the tasks file,
and "libcg" and other users don't appear to care about ordering.

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

cgroups: let ss->can_attach and ss->attach do whole threadgroups at a time

2009-09-24T14:20:58+00:00

Alter the ss->can_attach and ss->attach functions to be able to deal with
a whole threadgroup at a time, for use in cgroup_attach_proc.  (This is a
pre-patch to cgroup-procs-writable.patch.)

Currently, new mode of the attach function can only tell the subsystem
about the old cgroup of the threadgroup leader.  No subsystem currently
needs that information for each thread that's being moved, but if one were
to be added (for example, one that counts tasks within a group) this bit
would need to be reworked a bit to tell the subsystem the right
information.

[hidave.darkstar@gmail.com: fix build]
Signed-off-by: Ben Blum 
Signed-off-by: Paul Menage 
Acked-by: Li Zefan 
Reviewed-by: Matt Helsley 
Cc: "Eric W. Biederman" 
Cc: Oleg Nesterov 
Cc: Peter Zijlstra 
Cc: Ingo Molnar 
Cc: Dave Young 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroups: support named cgroups hierarchies

2009-09-24T14:20:57+00:00

To simplify referring to cgroup hierarchies in mount statements, and to
allow disambiguation in the presence of empty hierarchies and
multiply-bindable subsystems this patch adds support for naming a new
cgroup hierarchy via the "name=" mount option

A pre-existing hierarchy may be specified by either name or by subsystems;
a hierarchy's name cannot be changed by a remount operation.

Example usage:

# To create a hierarchy called "foo" containing the "cpu" subsystem
mount -t cgroup -oname=foo,cpu cgroup /mnt/cgroup1

# To mount the "foo" hierarchy on a second location
mount -t cgroup -oname=foo cgroup /mnt/cgroup2

Signed-off-by: Paul Menage 
Reviewed-by: Li Zefan 
Cc: KAMEZAWA Hiroyuki 
Cc: Balbir Singh 
Cc: Dhaval Giani 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial

2009-04-03T22:24:35+00:00

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (28 commits)
  trivial: Update my email address
  trivial: NULL noise: drivers/mtd/tests/mtd_*test.c
  trivial: NULL noise: drivers/media/dvb/frontends/drx397xD_fw.h
  trivial: Fix misspelling of "Celsius".
  trivial: remove unused variable 'path' in alloc_file()
  trivial: fix a pdlfush -> pdflush typo in comment
  trivial: jbd header comment typo fix for JBD_PARANOID_IOFAIL
  trivial: wusb: Storage class should be before const qualifier
  trivial: drivers/char/bsr.c: Storage class should be before const qualifier
  trivial: h8300: Storage class should be before const qualifier
  trivial: fix where cgroup documentation is not correctly referred to
  trivial: Give the right path in Documentation example
  trivial: MTD: remove EOL from MODULE_DESCRIPTION
  trivial: Fix typo in bio_split()'s documentation
  trivial: PWM: fix of #endif comment
  trivial: fix typos/grammar errors in Kconfig texts
  trivial: Fix misspelling of firmware
  trivial: cgroups: documentation typo and spelling corrections
  trivial: Update contact info for Jochen Hein
  trivial: fix typo "resgister" -> "register"
  ...