From: Benjamin Herrenschmidt <[EMAIL PROTECTED]> Date: Wed, 29 Nov 2006 09:57:24 +1100
> > > This looks mostly fine. > > > > I was thinking about the lockless stuff, and I wonder if there > > is a clever way you can get it back down to one PIO on the > > GREG_STAT register. > > > > I think you'd need to have the ->poll() clear gp->status, then > > do a smp_wb(), right before it re-enables interrupts. > > > > Then in the interrupt handler, you need to find a way to safely > > OR-in any unset bits in gp->status in a race-free manner. > > Having it atomic might work at a slightly smaller cost than a lock, > though atomics don't have strong ordering requirements so you'd still > have to be a bit careful. At least in theory the atomic + any necessary memory barriers would be cheaper than the extra PIO read we need otherwise. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
