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authorBen Blum <bblum@andrew.cmu.edu>2011-05-26 16:25:19 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-05-26 17:12:34 -0700
commitf780bdb7c1c73009cb57adcf99ef50027d80bf3c (patch)
treed15668ffcc40a2aaa31723b87cfda0b166f84d57 /kernel/cgroup_freezer.c
parent4714d1d32d97239fb5ae3e10521d3f133a899b66 (diff)
cgroups: add per-thread subsystem callbacks
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 <bblum@andrew.cmu.edu> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Matt Helsley <matthltc@us.ibm.com> Reviewed-by: Paul Menage <menage@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Miao Xie <miaox@cn.fujitsu.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.c26
1 files changed, 10 insertions, 16 deletions
diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c
index e7bebb7c6c3..e691818d7e4 100644
--- a/kernel/cgroup_freezer.c
+++ b/kernel/cgroup_freezer.c
@@ -160,7 +160,7 @@ static void freezer_destroy(struct cgroup_subsys *ss,
*/
static int freezer_can_attach(struct cgroup_subsys *ss,
struct cgroup *new_cgroup,
- struct task_struct *task, bool threadgroup)
+ struct task_struct *task)
{
struct freezer *freezer;
@@ -172,26 +172,17 @@ static int freezer_can_attach(struct cgroup_subsys *ss,
if (freezer->state != CGROUP_THAWED)
return -EBUSY;
+ return 0;
+}
+
+static int freezer_can_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
+{
rcu_read_lock();
- if (__cgroup_freezing_or_frozen(task)) {
+ if (__cgroup_freezing_or_frozen(tsk)) {
rcu_read_unlock();
return -EBUSY;
}
rcu_read_unlock();
-
- if (threadgroup) {
- struct task_struct *c;
-
- rcu_read_lock();
- list_for_each_entry_rcu(c, &task->thread_group, thread_group) {
- if (__cgroup_freezing_or_frozen(c)) {
- rcu_read_unlock();
- return -EBUSY;
- }
- }
- rcu_read_unlock();
- }
-
return 0;
}
@@ -390,6 +381,9 @@ struct cgroup_subsys freezer_subsys = {
.populate = freezer_populate,
.subsys_id = freezer_subsys_id,
.can_attach = freezer_can_attach,
+ .can_attach_task = freezer_can_attach_task,
+ .pre_attach = NULL,
+ .attach_task = NULL,
.attach = NULL,
.fork = freezer_fork,
.exit = NULL,