HI ,
In the latest patch mentioned, k should be their instead of p:
-WARN_ON_ONCE(!wait_task_inactive(p, TASK_PARKED))
+WARN_ON_ONCE(!wait_task_inactive(k, TASK_PARKED))
Regards
Gaurav
On 6/7/2018 12:29 AM, Peter Zijlstra wrote:
On Wed, Jun 06, 2018 at 03:51:16PM +0200, Oleg Nesterov wrote:
IIUC, this will only affect smpboot_update_cpumask_percpu_thread() which can hit
an already parked thread, but it doesn't need to wait.
And it seems that smpboot_update_cpumask_percpu_thread() in turn needs some
cleanups.
Hmm. and its single user: kernel/watchdog.c.
And speaking of watchdog.c, can't we simply kill the "watchdog/%u" threads?
This is
off-topic, but can't watchdog_timer_fn() use stop_one_cpu_nowait(watchdog) ?
And I really think we should unexport kthread_park/unpark(), only
smpboot_thread_fn()
should use them. kthread() should not play with __kthread_parkme(). And even
KTHREAD_SHOULD_PARK must die, I mean it should live in struct
smp_hotplug_thread,
not in struct kthread.
OK, this is off-topic too.
And, let me repeat, can't we avoid complete_all() ?
Yes, or at least if that watchdog crap is the only user.
I have most of the patch reworking watchdog.c to use stop_one_cpu*(),
and that cleans up lots -- of course, I've not tested it yet, so it
could also be breaking lots :-)
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