Re: [PATCH 02/10] writeback: switch to per-bdi threads for flushingdata

[Artem Bityutskiy]

Zhang, Yanmin wrote:
> > > +		list_for_each_entry_safe(bdi, tmp, &bdi_list, bdi_list) {
> > > +			if (bdi->task || !bdi_has_dirty_io(bdi))
> > > +				continue;
> > > +
> > > +			bdi_add_default_flusher_task(bdi);
> > > +		}
> > > +
> > > +		set_current_state(TASK_INTERRUPTIBLE);
> > > +
> > What happens if we are preempted here? Since we have TASK_INTERRUPTIBLE
> > state, we will not come back unless some other task wakes us up. Who
> > would wake us up in this case?
> If it's preempted (CONFIG_PREEMPT=y), it will stay in runqueue. Only when
> it calls schedule initiatively or calls schedule when exiting to user space,
> it will be moved out of runqueue if its state isn't TASK_RUNNING.
>
> See flag PREEMPT_ACTIVE.

OK, thanks for the hint!

--
Best Regards,
Artem Bityutskiy (ÐÑÑÑÐ ÐÐÑÑÑÐÐÐ)
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