[PATCH v2 03/23] cpu/hotplug: Avoid busy-polling on archs where cpu_relax() is a no-op

[Will Deacon]

On Fri, Oct 09, 2026 at 11:46:11AM +0100, David Woodhouse wrote:
> On Fri, 2026-10-09 at 11:07 +0100, Will Deacon wrote:
> > Change cpuhp_ap_sync_alive() to poll using atomic_cond_read_relaxed()
> 
> relaxed.
> 
> ...
> 
> > +       atomic_cond_read_acquire(st, VAL == SYNC_STATE_SHOULD_ONLINE);
> 
> acquire.

Oops, I'll fix the commit message. Thanks. I think we need acquire
semantics here so that the AP sees anything published by the BP prior to
advancing the state.

Will