Re: why are some atomic_t's not volatile, while most are?

Chris Friesen wrote:

Chris Snook wrote:

This is not a problem, since indirect references will cause the CPU to fetch the data from memory/cache anyway.

Isn't Zan's sample code (that shows the problem) already using indirect references?

Yeah, I misinterpreted his conclusion. I thought about this for a while, and realized that it's perfectly legal for the compiler to re-use a value obtained from atomic_read. All that matters is that the read itself was atomic. The use (or non-use) of the volatile keyword is really more relevant to the other atomic operations. If you want to guarantee a re-read from memory, use barrier(). This, incidentally, uses volatile under the hood.

	-- Chris
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