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

Jeremy Fitzhardinge
2009-01-10T23:59:14Z

Linus Torvalds wrote:
> Actually, the real spin locks are now fair. We use ticket locks on x86.
>
> 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.
>

No, it will continue to use ticket locks, but there's the option to
switch to byte locks or something else. Ticket locks are awesomely bad
when the VCPU scheduler fights with the run-order required by the ticket
order.

J