Re: Cache coherency... and locking
Manfred Spraul (manfred@colorfullife.com)
Fri, 21 Jul 2000 12:57:21 +0200
Keith Owens wrote:
>
>
> Linux requires strong write ordering[*]. That is, write A followed by
> write B will appear in memory in the order of A then B. So if any
> write on processor 1 is committed to memory then all preceding writes
> by processor 1 must already have been committed to memory.
>
Are you sure? Do you know a certain function that relies on strong write
ordering?
Neither ia64 nor the other RISC processors guarantee strong write
ordering.
spinlocks, semaphores, atomic_xy and the bit operations must be (at
least partial) memory barriers, but that's it.
--
Manfred
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