[patch 00/21] mutex subsystem, -V14

[Joel Schopp]

>>Here is a first pass at a powerpc file for the fast paths just as an FYI/RFC.
>>It is completely untested, but compiles.
> 
> 
> Shouldn't you make that "isync" dependent on SMP too? UP doesn't need it, 
> since DMA will never matter, and interrupts are precise.
> 
> 		Linus
> 

I think the isync is necessary to keep heavily out of order processors from 
getting ahead of themselves even on UP.  Scanning back through the powerpc 
spinlock code they seem to take the same view there as well.