Re: [PATCH v6 0/6] lockinig/rwsem: Fix rwsem bugs & enable true lock handoff

[Waiman Long]

On 1/22/23 08:46, Peter Zijlstra wrote:
> On Thu, Nov 17, 2022 at 09:20:10PM -0500, Waiman Long wrote:
>
> > Waiman Long (6):
> >    locking/rwsem: Prevent non-first waiter from spinning in down_write() slowpath
> >    locking/rwsem: Disable preemption at all down_read*() and up_read() code paths
> >    locking/rwsem: Disable preemption at all down_write*() and up_write() code paths
> >    locking/rwsem: Change waiter->hanodff_set to a handoff_state enum
> After all these we still have down_read_non_owner() using
> __rwsem_set_reader_owner() outside of the preempt_disable() region.
>
> Now, let me go stare at this one:

Thanks for spotting that. I kind of overlook the fact we have a 
down_read_non_owner(). Will update that as well.

Cheers,
Longman

> >    locking/rwsem: Enable direct rwsem lock handoff