Re: [PATCH -v7][RFC]: mutex: implement adaptive spinning

Jiri Kosina
2009-01-09T17:40:31Z

On Thu, 8 Jan 2009, Peter Zijlstra wrote:

> > Well, at least we do unless you enable that broken paravirt support.
> > I'm not at all clear on why CONFIG_PARAVIRT wants to use inferior
> > locks, but I don't much care.
> Because the virtual cpu that has the ticket might not get scheduled for
> a while, even though another vcpu with a spinner is scheduled.
> The whole (para)virt is a nightmare in that respect.

Hmm, are we in fact really using byte locks in CONFIG_PARAVIRT situation?
Where are we actually setting pv_lock_ops.spin_lock pointer to point to
__byte_spin_lock?

Such initialization seems to happen only in paravirt_use_bytelocks()
function, but my blind eyes prevent me from finding a callsite from which
this function would eventually get called.

--
Jiri Kosina
SUSE Labs