On Wed, Apr 17, 2024 at 09:57:04PM -0700, Christoph Hellwig wrote: > On Wed, Apr 17, 2024 at 08:00:22PM +0200, Mikulas Patocka wrote: > > > > +EXPORT_SYMBOL(wait_for_completion_long_io); > > > > > > Urgh, why is it a sane thing to circumvent the hang check timer? > > > > The block layer already does it - the bios can have arbitrary size, so > > waiting for them takes arbitrary time. > > And as mentioned the last few times around, I think we want a task > state to say that task can sleep long or even forever and not propagate > this hack even further. A bit like TASK_NOLOAD (which is used to make TASK_IDLE work), but different I suppose. TASK_NOHUNG would be trivial to add ofc. But is it worth it? Anyway, as per the other email, anything like this needs to come with a big fat warning. You get to keep the pieces etc.. --- diff --git a/include/linux/sched.h b/include/linux/sched.h index 3c2abbc587b4..83b25327c233 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -112,7 +112,8 @@ struct user_event_mm; #define TASK_FREEZABLE 0x00002000 #define __TASK_FREEZABLE_UNSAFE (0x00004000 * IS_ENABLED(CONFIG_LOCKDEP)) #define TASK_FROZEN 0x00008000 -#define TASK_STATE_MAX 0x00010000 +#define TASK_NOHUNG 0x00010000 +#define TASK_STATE_MAX 0x00020000 #define TASK_ANY (TASK_STATE_MAX-1) diff --git a/kernel/hung_task.c b/kernel/hung_task.c index b2fc2727d654..126fac835e5e 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -210,7 +210,8 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout) state = READ_ONCE(t->__state); if ((state & TASK_UNINTERRUPTIBLE) && !(state & TASK_WAKEKILL) && - !(state & TASK_NOLOAD)) + !(state & TASK_NOLOAD) && + !(state & TASK_NOHUNG)) check_hung_task(t, timeout); } unlock:
