cvs commit: src/sys/i386/i386 pmap.c

[Andre Oppermann]

John Baldwin wrote:
> 
> That's very easy, it's just critical_enter/exit() without the
> cpu_critical_*().  As mentioned in the SMP "design doc", the cpu_critical_*()
> are only needed for spin mutexes that are used in both top-half and
> bottom-half code (where ithreads are top-half, but "fast" interrupts and the
> code that schedules ithreads are bottom-half).  I've thought about shoving
> cpu_critical_*() off into another API that spin mutexes would use, but that
> not all critical sections would use, this would give us critical sections
> that don't block interrupts, but just block preempting.  For idle page
> zeroing though, I'm not sure we really want to use even a cheap critical
> section since it would still defer an ithread from running, and ithreads are
> more important than idle page zeroing.
> 
> Note that you can easily pin the current thread to its current CPU via
> sched_pin/unpin() and that that works across preemptions.

Does this involve any mutexes or so?  This is very interesting for a couple
of cases in the network stack which uses a lot of heavy-weight mutexes at
the moment.

-- 
Andre