Messages in this thread | | | From | Måns Rullgård <> | Subject | Re: [patch] spinlocks: remove 'volatile' | Date | Thu, 06 Jul 2006 20:41:54 +0100 |
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"Chris Friesen" <cfriesen@nortel.com> writes:
> Linus Torvalds wrote: > >> On Thu, 6 Jul 2006, Mark Lord wrote: > >>> A volatile declaration may be used to describe an object corresponding >>> to a memory-mapped input/output port or an object accessed by an >>> aysnchronously interrupting function. Actions on objects so declared >>> shall not be "optimized out" by an implementation or reordered except >>> as permitted by the rules for evaluating expressions. >> Note that the "reordered" is totally pointless. >> The _hardware_ will re-order accesses. Which is the whole >> point. "volatile" is basically never sufficient in itself. > > The "reordered" thing really only matters on SMP machines, no?
No, each CPU does write combining and write merging all on its own.
-- Måns Rullgård mru@inprovide.com
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