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authorBen Blum <bblum@google.com>2009-09-23 15:56:31 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-24 07:20:58 -0700
commitbe367d09927023d081f9199665c8500f69f14d22 (patch)
treef0c5b9da037506da3c5890cf11b51b39a7d3c427 /kernel/cgroup_freezer.c
parentc378369d8b4fa516ff2b1e79c3eded4e0e955ebb (diff)
cgroups: let ss->can_attach and ss->attach do whole threadgroups at a time
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 <bblum@google.com> Signed-off-by: Paul Menage <menage@google.com> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Reviewed-by: Matt Helsley <matthltc@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@elte.hu> Cc: Dave Young <hidave.darkstar@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/cgroup_freezer.c')
-rw-r--r--kernel/cgroup_freezer.c15
1 files changed, 14 insertions, 1 deletions
diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c
index fb249e2bcad..59e9ef6aab4 100644
--- a/kernel/cgroup_freezer.c
+++ b/kernel/cgroup_freezer.c
@@ -159,7 +159,7 @@ static bool is_task_frozen_enough(struct task_struct *task)
*/
static int freezer_can_attach(struct cgroup_subsys *ss,
struct cgroup *new_cgroup,
- struct task_struct *task)
+ struct task_struct *task, bool threadgroup)
{
struct freezer *freezer;
@@ -177,6 +177,19 @@ static int freezer_can_attach(struct cgroup_subsys *ss,
if (freezer->state == CGROUP_FROZEN)
return -EBUSY;
+ if (threadgroup) {
+ struct task_struct *c;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(c, &task->thread_group, thread_group) {
+ if (is_task_frozen_enough(c)) {
+ rcu_read_unlock();
+ return -EBUSY;
+ }
+ }
+ rcu_read_unlock();
+ }
+
return 0;
}