Messages in this thread | | | Subject | Re: [patch] spinlocks: remove 'volatile' | From | Thomas Gleixner <> | Date | Sat, 08 Jul 2006 12:28:06 +0200 |
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On Sat, 2006-07-08 at 13:18 +0300, Avi Kivity wrote:
> I didn't suggest the compiler could or should do it, just that it would > be possible (for the _user_) to write portable ISO C code to access PCI > mmio registers, if volatile's implementation serialized access.
And how is this portable on complex multibus architectures, where the PCI access goes through a couple of transports before hitting the PCI hardware ?
volatile has no notion of serialization. volatile guarantees that the compiler does not optimize and cache seemingly static values, i.e. it disables compiler optimizations.
tglx
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