linux.git/Documentation/cgroups/cgroups.txt, branch v2.6.39

Documentation: update cgroups info user groups names

2011-04-05T00:51:47+00:00

Update suitable words to explain / understand cgroups contents.

Signed-off-by: Geunsik Lim 
Cc: Paul Menage 
Signed-off-by: Randy Dunlap 
Signed-off-by: Linus Torvalds

Documentation: update cgroup pid and cpuset information

2011-03-16T17:47:04+00:00

The cgroup documentation does not specify how a process can be removed
from a particular group.  This patch adds a note at the end of the
simple example about how this is done.  Also, some cgroups (like
cpusets) require user input before a new group can be used.  This is
noted in the patch as well.

Signed-off-by: Eric B Munson 
Acked-by: Paul Menage 
Signed-off-by: Randy Dunlap 
Signed-off-by: Linus Torvalds

cgroups: remove deprecated subsystem from examples.

2011-01-13T16:03:16+00:00

The 'ns' cgroup is considered deprecated. Change the cgroup subsystem
used in the examples of the cgroup documentation from 'ns' to 'blkio'.

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

cgroup: add clone_children control file

2010-10-28T01:03:09+00:00

The ns_cgroup is a control group interacting with the namespaces.  When a
new namespace is created, a corresponding cgroup is automatically created
too.  The cgroup name is the pid of the process who did 'unshare' or the
child of 'clone'.

This cgroup is tied with the namespace because it prevents a process to
escape the control group and use the post_clone callback, so the child
cgroup inherits the values of the parent cgroup.

Unfortunately, the more we use this cgroup and the more we are facing
problems with it:

(1) when a process unshares, the cgroup name may conflict with a
    previous cgroup with the same pid, so unshare or clone return -EEXIST

(2) the cgroup creation is out of control because there may have an
    application creating several namespaces where the system will
    automatically create several cgroups in his back and let them on the
    cgroupfs (eg.  a vrf based on the network namespace).

(3) the mix of (1) and (2) force an administrator to regularly check
    and clean these cgroups.

This patchset removes the ns_cgroup by adding a new flag to the cgroup and
the cgroupfs mount option.  It enables the copy of the parent cgroup when
a child cgroup is created.  We can then safely remove the ns_cgroup as
this flag brings a compatibility.  We have now to manually create and add
the task to a cgroup, which is consistent with the cgroup framework.

This patch:

Sent as an answer to a previous thread around the ns_cgroup.

https://lists.linux-foundation.org/pipermail/containers/2009-June/018627.html

It adds a control file 'clone_children' for a cgroup.  This control file
is a boolean specifying if the child cgroup should be a clone of the
parent cgroup or not.  The default value is 'false'.

This flag makes the child cgroup to call the post_clone callback of all
the subsystem, if it is available.

At present, the cpuset is the only one which had implemented the
post_clone callback.

The option can be set at mount time by specifying the 'clone_children'
mount option.

Signed-off-by: Daniel Lezcano 
Signed-off-by: Serge E. Hallyn 
Cc: Eric W. Biederman 
Acked-by: Paul Menage 
Reviewed-by: Li Zefan 
Cc: Jamal Hadi Salim 
Cc: Matt Helsley 
Acked-by: Balbir Singh 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Documentation/cgroups/cgroups.txt: fix reference to "numtasks"

2010-05-27T16:12:43+00:00

Signed-off-by: Trevor Woerner 
Cc: Paul Menage 
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

2010-05-20T16:20:59+00:00

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (44 commits)
  vlynq: make whole Kconfig-menu dependant on architecture
  add descriptive comment for TIF_MEMDIE task flag declaration.
  EEPROM: max6875: Header file cleanup
  EEPROM: 93cx6: Header file cleanup
  EEPROM: Header file cleanup
  agp: use NULL instead of 0 when pointer is needed
  rtc-v3020: make bitfield unsigned
  PCI: make bitfield unsigned
  jbd2: use NULL instead of 0 when pointer is needed
  cciss: fix shadows sparse warning
  doc: inode uses a mutex instead of a semaphore.
  uml: i386: Avoid redefinition of NR_syscalls
  fix "seperate" typos in comments
  cocbalt_lcdfb: correct sections
  doc: Change urls for sparse
  Powerpc: wii: Fix typo in comment
  i2o: cleanup some exit paths
  Documentation/: it's -> its where appropriate
  UML: Fix compiler warning due to missing task_struct declaration
  UML: add kernel.h include to signal.c
  ...

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

Fix typos in comments

2010-03-16T10:47:56+00:00

[Ss]ytem => [Ss]ystem
udpate => update
paramters => parameters
orginal => original

Signed-off-by: Thomas Weber 
Acked-by: Randy Dunlap 
Signed-off-by: Jiri Kosina

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