Re: [PATCH 2/5] riscv: Add QUEUED_SPINLOCKS & QUEUED_RWLOCKS supported

Peter Zijlstra
2020-11-25T14:18:36Z

On Wed, Nov 25, 2020 at 08:52:23AM +0800, Guo Ren wrote:

> > I'm pretty sure there's a handfull of implementations like this out
> > there... if only we could share.
> Michael has sent qspinlock before, ref to Link below. He reused mips' code.
>
> Link: https://lore.kernel.org/linux-riscv/20190211043829.30096-1-michaeljclark@mac.com/
>
> Which short xchg implementation do you prefer (Mine or his)?

Well, it would be very nice to have mips/riscv/csky all use the same
header to implement these I suppose.

But then we're back to a cmpxchg-loop, in which case Arnd's suggestion
isn't worse.