linux-toradex.git/Documentation/cgroups/cgroups.txt, branch v3.4

cgroup: remove cgroup_subsys argument from callbacks

2012-02-02T17:20:22+00:00

The argument is not used at all, and it's not necessary, because
a specific callback handler of course knows which subsys it
belongs to.

Now only ->pupulate() takes this argument, because the handlers of
this callback always call cgroup_add_file()/cgroup_add_files().

So we reduce a few lines of code, though the shrinking of object size
is minimal.

 16 files changed, 113 insertions(+), 162 deletions(-)

   text    data     bss     dec     hex filename
5486240  656987 7039960 13183187         c928d3 vmlinux.o.orig
5486170  656987 7039960 13183117         c9288d vmlinux.o

Signed-off-by: Li Zefan 
Signed-off-by: Tejun Heo

cgroup: kill subsys->can_attach_task(), pre_attach() and attach_task()

2011-12-13T02:12:22+00:00

These three methods are no longer used.  Kill them.

Signed-off-by: Tejun Heo 
Reviewed-by: KAMEZAWA Hiroyuki 
Reviewed-by: Frederic Weisbecker 
Acked-by: Paul Menage 
Cc: Li Zefan

cgroup: introduce cgroup_taskset and use it in subsys->can_attach(), cancel_attach() and attach()

2011-12-13T02:12:21+00:00

Currently, there's no way to pass multiple tasks to cgroup_subsys
methods necessitating the need for separate per-process and per-task
methods.  This patch introduces cgroup_taskset which can be used to
pass multiple tasks and their associated cgroups to cgroup_subsys
methods.

Three methods - can_attach(), cancel_attach() and attach() - are
converted to use cgroup_taskset.  This unifies passed parameters so
that all methods have access to all information.  Conversions in this
patchset are identical and don't introduce any behavior change.

-v2: documentation updated as per Paul Menage's suggestion.

Signed-off-by: Tejun Heo 
Reviewed-by: KAMEZAWA Hiroyuki 
Reviewed-by: Frederic Weisbecker 
Acked-by: Paul Menage 
Acked-by: Li Zefan 
Cc: Balbir Singh 
Cc: Daisuke Nishimura 
Cc: KAMEZAWA Hiroyuki 
Cc: James Morris

Documentation: update cgroups notes

2011-11-04T19:01:46+00:00

- ns cgroup has been removed.
- it's true moving a task to another cgroup can fail.

Signed-off-by: Li Zefan 
Acked-by: Paul Menage 
Signed-off-by: Randy Dunlap 
Signed-off-by: Linus Torvalds

Documentation: fix cgroup typos and formatting

2011-06-16T04:52:50+00:00

Fix format and spelling.

Signed-off-by: Jörg Sommer 
Acked-by: Paul Menage 
Signed-off-by: Randy Dunlap 
Signed-off-by: Linus Torvalds

Documentation: update cgroupfs mount point

2011-06-16T04:52:50+00:00

According to commit 676db4af0430 ("cgroupfs: create /sys/fs/cgroup to
mount cgroupfs on") the canonical mountpoint for the cgroup filesystem
is /sys/fs/cgroup.  Hence, this should be used in the documentation.

Signed-off-by: Jörg Sommer 
Acked-by: Paul Menage 
Signed-off-by: Randy Dunlap 
Signed-off-by: Linus Torvalds

cgroup: remove the ns_cgroup

2011-05-27T00:12:34+00:00

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

cgroups: make procs file writable

2011-05-27T00:12:34+00:00

Make procs file writable to move all threads by tgid at once.

Add functionality that enables users to move all threads in a threadgroup
at once to a cgroup by writing the tgid to the 'cgroup.procs' file.  This
current implementation makes use of a per-threadgroup rwsem that's taken
for reading in the fork() path to prevent newly forking threads within the
threadgroup from "escaping" while the move is in progress.

Signed-off-by: Ben Blum 
Cc: "Eric W. Biederman" 
Cc: Li Zefan 
Cc: Matt Helsley 
Reviewed-by: Paul Menage 
Cc: Oleg Nesterov 
Cc: David Rientjes 
Cc: Miao Xie 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroups: add per-thread subsystem callbacks

2011-05-27T00:12:34+00:00

Add cgroup subsystem callbacks for per-thread attachment in atomic contexts

Add can_attach_task(), pre_attach(), and attach_task() as new callbacks
for cgroups's subsystem interface.  Unlike can_attach and attach, these
are for per-thread operations, to be called potentially many times when
attaching an entire threadgroup.

Also, the old "bool threadgroup" interface is removed, as replaced by
this.  All subsystems are modified for the new interface - of note is
cpuset, which requires from/to nodemasks for attach to be globally scoped
(though per-cpuset would work too) to persist from its pre_attach to
attach_task and attach.

This is a pre-patch for cgroup-procs-writable.patch.

Signed-off-by: Ben Blum 
Cc: "Eric W. Biederman" 
Cc: Li Zefan 
Cc: Matt Helsley 
Reviewed-by: Paul Menage 
Cc: Oleg Nesterov 
Cc: David Rientjes 
Cc: Miao Xie 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

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