Re: spin_lock behavior with ARM64 big.Little/HMP

[Sudeep Holla]

On 30/03/17 05:12, Vikram Mulukutla wrote:
> 
> Hi Sudeep,
> 
>>
>> Interesting. Just curious if this is r0p0/p1 A53 ? If so, is the errata
>> 819472 enabled ?
> 
> Sorry for bringing this up after the loo-ong delay, but I've been
> assured that the A53 involved is > r0p1. I've also confirmed this
> problem on multiple internal platforms, and I'm pretty sure that it
> occurs on any b.L out there today. Also, we found the same problematic
> lock design used in the workqueue code in the kernel, causing the same
> livelock. It's very very rare and requires a perfect set of circumstances.
> 
> If it would help I can provide a unit test if you folks would be
> generous enough to test it on the latest Juno or something b.L that's
> also upstream.
> 

Sure, please do share the unit test. I will give that a try on Juno.

-- 
Regards,
Sudeep