Satyam Sharma wrote:
>
>> + - Pointers to data structures in coherent memory which might be
>> modified
>> + by I/O devices can, sometimes, legitimately be volatile. A ring
>> buffer
>> + used by a network adapter, where that adapter changes pointers to
>> + indicate which descriptors have been processed, is an example of
>> this
>> + type of situation.
>
> is a legitimate use case for volatile is still not clear to me (I
> agree with Alan's
> comment in a previous thread that this seems to be a case where a memory
> barrier would be applicable^Wbetter, actually). I could be wrong here, so
> would be nice if Peter explains why volatile is legitimate here.
>
> Otherwise, it's fine with me.
>
I don't see why Alan's way is necessarily better; it should work but is
more heavy-handed as it's disabling *all* optimization such as loop
invariants across the barrier.
-hpa
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