diff options
| -rw-r--r-- | kernel/cgroup_freezer.c | 43 |
1 files changed, 26 insertions, 17 deletions
diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c index b08722de610c..df884022fbd9 100644 --- a/kernel/cgroup_freezer.c +++ b/kernel/cgroup_freezer.c @@ -145,22 +145,40 @@ static void freezer_destroy(struct cgroup_subsys *ss, kfree(cgroup_freezer(cgroup)); } +/* Task is frozen or will freeze immediately when next it gets woken */ +static bool is_task_frozen_enough(struct task_struct *task) +{ + return frozen(task) || + (task_is_stopped_or_traced(task) && freezing(task)); +} +/* + * The call to cgroup_lock() in the freezer.state write method prevents + * a write to that file racing against an attach, and hence the + * can_attach() result will remain valid until the attach completes. + */ static int freezer_can_attach(struct cgroup_subsys *ss, struct cgroup *new_cgroup, struct task_struct *task) { struct freezer *freezer; - int retval = 0; + int retval; + + /* Anything frozen can't move or be moved to/from */ + + if (is_task_frozen_enough(task)) + return -EBUSY; - /* - * The call to cgroup_lock() in the freezer.state write method prevents - * a write to that file racing against an attach, and hence the - * can_attach() result will remain valid until the attach completes. - */ freezer = cgroup_freezer(new_cgroup); if (freezer->state == STATE_FROZEN) + return -EBUSY; + + retval = 0; + task_lock(task); + freezer = task_freezer(task); + if (freezer->state == STATE_FROZEN) retval = -EBUSY; + task_unlock(task); return retval; } @@ -193,12 +211,7 @@ static void check_if_frozen(struct cgroup *cgroup, cgroup_iter_start(cgroup, &it); while ((task = cgroup_iter_next(cgroup, &it))) { ntotal++; - /* - * Task is frozen or will freeze immediately when next it gets - * woken - */ - if (frozen(task) || - (task_is_stopped_or_traced(task) && freezing(task))) + if (is_task_frozen_enough(task)) nfrozen++; } @@ -249,11 +262,7 @@ static int try_to_freeze_cgroup(struct cgroup *cgroup, struct freezer *freezer) while ((task = cgroup_iter_next(cgroup, &it))) { if (!freeze_task(task, true)) continue; - if (task_is_stopped_or_traced(task) && freezing(task)) - /* - * The freeze flag is set so these tasks will - * immediately go into the fridge upon waking. - */ + if (is_task_frozen_enough(task)) continue; if (!freezing(task) && !freezer_should_skip(task)) num_cant_freeze_now++; |