Re: RT patch acceptance

john cooper
2005-05-26T23:59:12Z

Sven-Thorsten Dietrich wrote:
> On Thu, 2005-05-26 at 22:27 +0200, Andi Kleen wrote:
>
>>>Here, I am talking about separating out the patch, and applying it
>>>first, not dropping it from the RT implementation.
>>
>>I really dislike the idea of interrupt threads. It seems totally
>>wrong to me to make such a fundamental operation as an interrupt
>>much slower. If really any interrupts take too long they should
>>move to workqueues instead and be preempted there. But keep
>>the basic fundamental operations fast please (at least that used to be one
>>of the Linux mottos that served it very well for many years, although more
>>and more people seem to forget it now)
>
> IRQ threads are configurable. If you don't want them, you CAN turn them
> off (if you have already turned them on).
>
> You don't HAVE to turn them on.

Unless you have configured PREEMPT_RT which requires
PREEMPT_SOFTIRQS and PREEMPT_HARDIRQS such that
spinlock-mutexes are able to synchronize interrupt
processing. In other PREEMPT_* configuration modes
inclusion of IRQ threads is optional.

I think this may have been the source of confusion in
prior discussions.

-john

--
john.cooper@timesys.com