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    SubjectRe: [PATCH v4 3/4] locking/qspinlock: Add ARCH_USE_QUEUED_SPINLOCKS_XCHG32
    On Wed, Apr 07, 2021 at 05:52:36PM +0200, Peter Zijlstra wrote:
    > 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.

    Again, the longer answer is that this applies identically to LL/SC and
    I'm sure we actually have (or had) an architecture in tree that did just
    that. I just cannot remember which architecture that was.

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