Re: [PATCH v4 3/4] locking/qspinlock: Add ARCH_USE_QUEUED_SPINLOCKS_XCHG32

Peter Zijlstra
2021-04-07T15:54:34Z

On Wed, Apr 07, 2021 at 04:29:12PM +0200, Christoph Müllner wrote:
> The comparison with sparc64 is not applicable, as sparc64 does not
> have LL/SC instructions.

Sparc64 has CAS, without hardware fwd progress. It has to do software
backoff for failed CAS in order to do software fwd progress.