Re: [PATCH] ACPICA: don't cond_resched() when irq_disabled or in_atomic

From: Alexey Starikovskiy
Date: Thu Dec 10 2009 - 13:38:08 EST


Pavel Machek ÐÐÑÐÑ:
> On Thu 2009-12-10 20:58:45, Alexey Starikovskiy wrote:
>
>> Hi Pavel,
>>
>> Please elaborate... Your comments "ugly as hell" are too often to be
>> specific...
>> There is only one use of ACPI_PREEMPTION_POINT(), and it is in the
>> ACPICA code,
>> which we all agreed to keep OS independent, thus the need for #define.
>> Do you see any other way to add preemption point without introducing
>> Linux-specific
>> code into ACPICA?
>>
>
> I believe we want linux-specific code in acpica at this point.
>
>
The point there we call cond_resched() in ACPICA is an interpreter parse
loop. This parse loop may be executed from within atomic context and even
with interrupts off. In this case, cond_resched() should not be called
to not make
might_sleep() guards angry.

Please post the code, which will do the above and will not look "ugly as
hell".
I still don't follow your vague comments.
> (Or maybe... I guess other systems have concept of preemption and not
> all actions are permitted from all contexts, so maybe something like
> that would be important for them, too?)
>
None of them cared about it up to this point.
With the macro above we allowed them to follow Linux, but to go or not
is their call.

Regards,
Alex.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/