Re: Memory barriers and spin_unlock safety

[David Howells]

Linus Torvalds <torvalds@xxxxxxxx> wrote:

> Note that _normal_ writes never need an SFENCE, because they are ordered 
> by the core.
> 
> The reason to use SFENCE is because of _special_ writes.

I suspect, then, that x86_64 should not have an SFENCE for smp_wmb(), and that
only io_wmb() should have that.

David
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/