Re: acpi_os_queue_for_execution()

[Pavel Machek]

Hi!

> > Acpi seems to create short-lived kernel threads, and I don't quite
> > understand why. 
> > 
> > In thermal.c
> > 
> > 
> >                         tz->timer.data = (unsigned long) tz;
> >                         tz->timer.function = acpi_thermal_run;
> >                         tz->timer.expires = jiffies + (HZ * sleep_time) / 1000;
> >                         add_timer(&(tz->timer));
> > 
> > and acpi_thermal_run creates kernel therad that runs
> > acpi_thermal_check. Why is not acpi_thermal_check called directly? I
> > don't like idea of thread being created every time thermal zone needs
> > to be polled...
> 
> This is the standard way to get process context [i.e. somewhere where
> you can sleep].  The new delayed-work workqueue code in 2.5.x does
> something almost exactly like that under the covers.

Is it really true that fork() can not sleep?

> That said, it sounds like you found something to fix in ACPI:
> 
> In 2.4.x ACPI, it should be using schedule_task(), and in 2.5.x it should
> be using schedule_work(), if this is truly the intention of the ACPI
> subsystem.

Agreed.
								Pavel

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