diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2018-06-07 10:55:56 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2018-07-03 09:20:44 +0200 |
| commit | f83ee19be4272564ad592ef90145db7295229490 (patch) | |
| tree | 181bd1628e2b233cd9e3b44ac6e608c24b7f34b4 /kernel/kthread.c | |
| parent | 167a88677b05d6a810f23b871cfb2b5db1808e60 (diff) | |
kthread: Simplify kthread_park() completion
Oleg explains the reason we could hit park+park is that
smpboot_update_cpumask_percpu_thread()'s
for_each_cpu_and(cpu, &tmp, cpu_online_mask)
smpboot_park_kthread();
turns into:
for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask, (void)and)
smpboot_park_kthread();
on UP, ignoring the mask. But since we just completely removed that
function, this is no longer relevant.
So revert commit:
b1f5b378e126 ("kthread: Allow kthread_park() on a parked kthread")
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/kthread.c')
| -rw-r--r-- | kernel/kthread.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/kernel/kthread.c b/kernel/kthread.c index 750cb8082694..11b591ee51ab 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -190,7 +190,7 @@ static void __kthread_parkme(struct kthread *self) if (!test_bit(KTHREAD_SHOULD_PARK, &self->flags)) break; - complete_all(&self->parked); + complete(&self->parked); schedule(); } __set_current_state(TASK_RUNNING); @@ -465,7 +465,6 @@ void kthread_unpark(struct task_struct *k) if (test_bit(KTHREAD_IS_PER_CPU, &kthread->flags)) __kthread_bind(k, kthread->cpu, TASK_PARKED); - reinit_completion(&kthread->parked); clear_bit(KTHREAD_SHOULD_PARK, &kthread->flags); /* * __kthread_parkme() will either see !SHOULD_PARK or get the wakeup. @@ -493,6 +492,9 @@ int kthread_park(struct task_struct *k) if (WARN_ON(k->flags & PF_EXITING)) return -ENOSYS; + if (WARN_ON_ONCE(test_bit(KTHREAD_SHOULD_PARK, &kthread->flags))) + return -EBUSY; + set_bit(KTHREAD_SHOULD_PARK, &kthread->flags); if (k != current) { wake_up_process(k); |