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Date:   Wed, 7 Apr 2021 17:52:36 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Christoph =?iso-8859-1?Q?M=FCllner?= <christophm30@gmail.com>
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Subject: Re: [PATCH v4 3/4] locking/qspinlock: Add
 ARCH_USE_QUEUED_SPINLOCKS_XCHG32
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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.