[RFC] implement QUEUED spinlocks on powerpc

[Michael Ellerman]

Benjamin Herrenschmidt <benh at kernel.crashing.org> writes:

> On Wed, 2017-02-01 at 09:05 -0800, Eric Dumazet wrote:
>> Hi all
>> 
>> Is anybody working on adding QUEUED spinlocks to powerpc 64bit ?
>> 
>> I've seen past attempts with ticket spinlocks
>> ( https://patchwork.ozlabs.org/patch/449381/ and other related links
>> )
>> 
>> But it looks ticket spinlocks are a thing of the past.
>
> Yes, we have a tentative implementation of qspinlock and pv variants:
>
> https://patchwork.ozlabs.org/patch/703139/
> https://patchwork.ozlabs.org/patch/703140/
> https://patchwork.ozlabs.org/patch/703141/
> https://patchwork.ozlabs.org/patch/703142/
> https://patchwork.ozlabs.org/patch/703143/
> https://patchwork.ozlabs.org/patch/703144/
>
> Michael, what's the status with getting that merged ?

Needs a good review, and the benchmark results were not all that
compelling - though perhaps they were just the wrong benchmarks.

cheers