diff options
Diffstat (limited to 'kernel/freezer.c')
| -rw-r--r-- | kernel/freezer.c | 78 |
1 files changed, 45 insertions, 33 deletions
diff --git a/kernel/freezer.c b/kernel/freezer.c index 4fad0e6fca64..a76bf957fb32 100644 --- a/kernel/freezer.c +++ b/kernel/freezer.c @@ -10,6 +10,7 @@ #include <linux/export.h> #include <linux/syscalls.h> #include <linux/freezer.h> +#include <linux/oom.h> #include <linux/kthread.h> /* total number of freezing conditions in effect */ @@ -40,10 +41,10 @@ bool freezing_slow_path(struct task_struct *p) if (p->flags & (PF_NOFREEZE | PF_SUSPEND_TASK)) return false; - if (test_tsk_thread_flag(p, TIF_MEMDIE)) + if (tsk_is_oom_victim(p)) return false; - if (pm_nosig_freezing || cgroup_freezing(p)) + if (pm_nosig_freezing || cgroup1_freezing(p)) return true; if (pm_freezing && !(p->flags & PF_KTHREAD)) @@ -71,7 +72,11 @@ bool __refrigerator(bool check_kthr_stop) for (;;) { bool freeze; - set_current_state(TASK_FROZEN); + raw_spin_lock_irq(¤t->pi_lock); + WRITE_ONCE(current->__state, TASK_FROZEN); + /* unstale saved_state so that __thaw_task() will wake us up */ + current->saved_state = TASK_RUNNING; + raw_spin_unlock_irq(¤t->pi_lock); spin_lock_irq(&freezer_lock); freeze = freezing(current) && !(check_kthr_stop && kthread_should_stop()); @@ -105,7 +110,12 @@ static int __set_task_frozen(struct task_struct *p, void *arg) { unsigned int state = READ_ONCE(p->__state); - if (p->on_rq) + /* + * Allow freezing the sched_delayed tasks; they will not execute until + * ttwu() fixes them up, so it is safe to swap their state now, instead + * of waiting for them to get fully dequeued. + */ + if (task_is_runnable(p)) return 0; if (p != current && task_curr(p)) @@ -129,6 +139,7 @@ static int __set_task_frozen(struct task_struct *p, void *arg) WARN_ON_ONCE(debug_locks && p->lockdep_depth); #endif + p->saved_state = p->__state; WRITE_ONCE(p->__state, TASK_FROZEN); return TASK_FROZEN; } @@ -170,46 +181,47 @@ bool freeze_task(struct task_struct *p) } /* - * The special task states (TASK_STOPPED, TASK_TRACED) keep their canonical - * state in p->jobctl. If either of them got a wakeup that was missed because - * TASK_FROZEN, then their canonical state reflects that and the below will - * refuse to restore the special state and instead issue the wakeup. + * Restore the saved_state before the task entered freezer. For typical task + * in the __refrigerator(), saved_state == TASK_RUNNING so nothing happens + * here. For tasks which were TASK_NORMAL | TASK_FREEZABLE, their initial state + * is restored unless they got an expected wakeup (see ttwu_state_match()). + * Returns 1 if the task state was restored. */ -static int __set_task_special(struct task_struct *p, void *arg) +static int __restore_freezer_state(struct task_struct *p, void *arg) { - unsigned int state = 0; - - if (p->jobctl & JOBCTL_TRACED) - state = TASK_TRACED; - - else if (p->jobctl & JOBCTL_STOPPED) - state = TASK_STOPPED; + unsigned int state = p->saved_state; - if (state) + if (state != TASK_RUNNING) { WRITE_ONCE(p->__state, state); + p->saved_state = TASK_RUNNING; + return 1; + } - return state; + return 0; } void __thaw_task(struct task_struct *p) { - unsigned long flags, flags2; + guard(spinlock_irqsave)(&freezer_lock); + if (frozen(p) && !task_call_func(p, __restore_freezer_state, NULL)) + wake_up_state(p, TASK_FROZEN); +} - spin_lock_irqsave(&freezer_lock, flags); - if (WARN_ON_ONCE(freezing(p))) - goto unlock; - - if (lock_task_sighand(p, &flags2)) { - /* TASK_FROZEN -> TASK_{STOPPED,TRACED} */ - bool ret = task_call_func(p, __set_task_special, NULL); - unlock_task_sighand(p, &flags2); - if (ret) - goto unlock; - } +/* + * thaw_process - Thaw a frozen process + * @p: the process to be thawed + * + * Iterate over all threads of @p and call __thaw_task() on each. + */ +void thaw_process(struct task_struct *p) +{ + struct task_struct *t; - wake_up_state(p, TASK_FROZEN); -unlock: - spin_unlock_irqrestore(&freezer_lock, flags); + rcu_read_lock(); + for_each_thread(p, t) { + __thaw_task(t); + } + rcu_read_unlock(); } /** |