Messages in this thread | | | Date | Thu, 12 Nov 2015 22:49:02 +0800 | From | Boqun Feng <> | Subject | Re: [PATCH 4/4] locking: Introduce smp_cond_acquire() |
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On Thu, Nov 12, 2015 at 06:40:04AM -0800, Paul E. McKenney wrote: [snip] > > I cannot resist suggesting that any lock that interacts with > spin_unlock_wait() must have all relevant acquisitions followed by > smp_mb__after_unlock_lock(). >
But
1. This would expand the purpose of smp_mb__after_unlock_lock(), right? smp_mb__after_unlock_lock() is for making UNLOCK-LOCK pair global transitive rather than guaranteeing no operations can be reorder before the STORE part of LOCK/ACQUIRE.
2. If ARM64 has the same problem as PPC now, smp_mb__after_unlock_lock() can't help, as it's a no-op on ARM64.
Regards, Boqun [unhandled content-type:application/pgp-signature] | |