cvs commit: src/sys/kern sched_ule.c

[Jeff Roberson]

On Thu, 27 Sep 2007, Peter Grehan wrote:

>>    - Assert that we're not trying to compile ULE on an unsupported
>>      architecture.  To date, I believe only i386 and amd64 have implemented
>>      the third cpu switch argument required.
>
> ARM has it:
>
> http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/arm/arm/swtch.S?r1=1.20#rev1.20

Oh excellent Peter.  I hadn't seen that.  Did you verify that it works? 
Does arm support SMP?  It looks like it does not?

>
> PPC doesn't, though I think you told me that it was only required when 
> running MP. Is that still the case ?

For UP it doesn't need to wait for blocked lock to clear but it does need 
to set td_lock.  On UP there are no special synchronization requirements 
so it can happen as the very first instruction in cpu_switch.

Jeff

>
> later,
>
> Peter.
>