STORE *X = c, d = LOAD *X
- (Loads and stores overlap if they are targetted at overlapping pieces of
+ (Loads and stores overlap if they are targeted at overlapping pieces of
memory).
And there are a number of things that _must_ or _must_not_ be assumed:
In the above example, CPU 2 perceives that B is 7, despite the load of *C
-(which would be B) coming after the the LOAD of C.
+(which would be B) coming after the LOAD of C.
If, however, a data dependency barrier were to be placed between the load of C
and the load of *C (ie: B) on CPU 2:
(*) set_mb(var, value)
- This assigns the value to the variable and then inserts at least a write
+ This assigns the value to the variable and then inserts a full memory
barrier after it, depending on the function. It isn't guaranteed to
insert anything more than a compiler barrier in a UP compilation.
smp_wmb();
<A:modify v=2> <C:busy>
<C:queue v=2>
- p = &b; q = p;
+ p = &v; q = p;
<D:request p>
<B:modify p=&v> <D:commit p=&v>
<D:read p>
access depends on a read, not all do, so it may not be relied on.
Other CPUs may also have split caches, but must coordinate between the various
-cachelets for normal memory accesss. The semantics of the Alpha removes the
+cachelets for normal memory accesses. The semantics of the Alpha removes the
need for coordination in absence of memory barriers.