Stephen wrote:

[snip - memory barrier for fr_write_begin]

>Using mb() is more paranoid than necessary. 


What about the memory barrier in fr_read_begin?
If I understand the Intel documentation correctly, then i386 doesn't need them:
"Writes by a single processor are observed in the same order by all processors"

I think "smp_read_barrier_depends()" (i.e. a nop for i386) is sufficient. Attached is a test app - could someone try it? I don't have access to a SMP system right now.


What about permitting arch overrides for the memory barriers? E.g. ia64 has acquire and release memory barriers - it doesn't map to the Linux wmb()/rmb() scheme.

--
	Manfred