Re: [patch 2/2] x86,pat Convert memtype_lock into an rw_lock.

From: Suresh Siddha
Date: Wed Mar 24 2010 - 12:13:45 EST


On Wed, 2010-03-24 at 04:32 -0700, Peter Zijlstra wrote:
> On Wed, 2010-03-17 at 16:19 -0800, Suresh Siddha wrote:
> > On Wed, 2010-03-17 at 12:51 -0700, H. Peter Anvin wrote:
> > > Well, as you know :) tglx and I are on the road ... I'll try to get to it on Friday before I take off again.
> >
> > Also I talked to Thomas about this rwlock conversion and he referred to
> > RT issues with rwlock. And the best is to avoid this using RCU.
>
> Its not just RT, even for mainline rwlock_t is a massive pain and often
> is no better (actually worse) than a spinlock due to the massive
> cacheline bouncing it introduces.

Don't we have the same cacheline bouncing issues with the ticket
spinlocks?

thanks,
suresh

--
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/