Re: Opinion on ordering of writel vs. stores to RAM

From: Linus Torvalds
Date: Fri Sep 08 2006 - 23:51:23 EST




On Sat, 9 Sep 2006, Paul Mackerras wrote:
> >
> > although it's quite possible that (a) never makes any sense at all.
>
> Do you mean (b) never makes sense?

Yes.

> I suspect the best thing at this point is to move the sync in writeX()
> before the store, as you suggest, and add an "eieio" before the load
> in readX(). That does mean that we are then relying on driver writers
> putting in the mmiowb() between a writeX() and a spin_unlock, but at
> least that is documented.

Yeah, that sounds reasonable.

Linus
-
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/