On Mon, 22 Apr 2024, Peter Zijlstra wrote: > 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.. This seems better than the blk_wait_io hack. Reviewed-by: Mikulas Patocka <mpatocka@xxxxxxxxxx> > --- > 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: >
