Re: [PATCH 5/7] cgroup_freezer: allow moving tasks in and out of a frozen cgroup
From: Oleg Nesterov <hidden>
Date: 2012-10-22 19:24:06
Also in:
lkml
Tha last question ;) On 10/16, Tejun Heo wrote:
quoted hunk ↗ jump to hunk
@@ -190,12 +201,12 @@ static void freezer_fork(struct task_struct *task) goto out; spin_lock_irq(&freezer->lock); - BUG_ON(freezer->state == CGROUP_FROZEN); - - /* Locking avoids race with FREEZING -> THAWED transitions. */ - if (freezer->state == CGROUP_FREEZING) + /* + * @task might have been just migrated into a FROZEN cgroup.
Confused. If it was migrated, then freezer_attach() should take care do freeze_task? IOW,
Test + * equality with THAWED. Read the comment in freezer_attach(). + */ + if (freezer->state != CGROUP_THAWED) freeze_task(task); -
This can only happen in the "normal" case, when a CGROUP_FREEZING task forks the new child. So we could even do BUG_ON(state = CGROUP_FROZEN). Or there could be another reason? Oleg.