linux-toradex.git/kernel/cgroup.c, branch v2.6.25-rc2

Handle pid namespaces in cgroups code

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

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: Pavel Emelyanov 
Cc: "Eric W. Biederman" 
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

kernel/cgroup.c: make 2 functions static

2008-02-07T16:42:18+00:00

cgroup_is_releasable() and notify_on_release() should be static,
not global inline.

Signed-off-by: Adrian Bunk 
Acked-by: Paul Menage 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroups: move cgroups destroy() callbacks to cgroup_diput()

2008-02-07T16:42:18+00:00

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: Paul Menage 
Cc: Paul Jackson 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroup simplify space stripping

2008-02-07T16:42:18+00:00

Simplify the space stripping code in cgroup file write.

[akpm@linux-foundation.org: s/BUG_ON/BUILD_BUG_ON/]
Signed-off-by: Paul Jackson 
Acked-by: Paul Menage 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroup brace coding style fix

2008-02-07T16:42:17+00:00

Coding style fix - one line conditionals don't get braces.

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

kernel/cgroup.c: remove dead code

2008-02-07T16:42:17+00:00

This patch removes dead code spotted by the Coverity checker
(look at the "(nbytes >= PATH_MAX)" check).

Signed-off-by: Adrian Bunk 
Cc: Paul Jackson 
Cc: Paul Menage 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Improve cgroup printks

2007-11-15T02:45:37+00:00

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: Diego Calleja 
Cc: Paul Menage 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds