+/*
+ * _InterlockedExchange() generates a full memory barrier (or release
+ * semantics that ensures all prior memory operations are visible to
+ * other cores before the lock is released.
+ */
+#define S_UNLOCK(lock) (InterlockedExchange(lock, 0))
This seems to change the implementation from
#define S_UNLOCK(lock) \
do { _ReadWriteBarrier(); (*(lock)) = 0; } while (0)
in some cases, but I am insufficiently caffeinated to figure out what
platforms use which implementation. In any case, it looks like we are
changing it for some currently-supported platforms, and I'm curious why.
Perhaps there's some way to make the #ifdefs a bit more readable, too
(e.g., a prerequisite patch that rearranges things).
The rest looks generally reasonable to me.
--
nathan
