Re: [PATCH-tip v3 02/14] locking/rwsem: Make owner available even if !CONFIG_RWSEM_SPIN_ON_OWNER

[Waiman Long]

On 04/12/2019 12:41 PM, Ingo Molnar wrote:
> * Waiman Long <longman@xxxxxxxxxx> wrote:
>
>>> BTW, the v3 patch that I posted yesterday should work fine as long as
>>> CONFIG_RWSEM_SPIN_ON_OWNER is defined.
>>>
>>> Cheers,
>>> Longman
>>>
>> Oh, I see that the WIP.locking/core is currently merged into master. I
>> would say rwsem part1 patchset and patch 1 of part2 are stable. So I
>> would suggest merging those into the the master will be good. The rests
>> are still under review until I get an OK from Peter. If they miss the
>> next merge window and have to postpone to 5.3, I am fine with that.
> So beyond the primary constraint of PeterZ OK-ing it all, there's also 
> these two scalability regression reports from the ktest bot:
>
>  [locking/rwsem] 1b94536f2d: stress-ng.bad-altstack.ops_per_sec -32.7% regression

A regression due to the lock handoff patch is kind of expected, but I
will into why there is such a large drop.

>  [locking/rwsem] adc32e8877: will-it-scale.per_thread_ops -21.0% regression

Will look into that also.

Thanks,
Longman