Messages in this thread | | | Date | Wed, 24 Aug 2016 17:34:12 +0200 | From | Peter Zijlstra <> | Subject | Re: [RFC][PATCH 1/3] locking/mutex: Rework mutex::owner |
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On Wed, Aug 24, 2016 at 10:56:59AM +0100, Will Deacon wrote: > > + owner = atomic_long_read(&lock->owner); > > + for (;;) { > > + unsigned long old; > > + > > + old = atomic_long_cmpxchg_release(&lock->owner, owner, owner & 0x03); > > + if (old == owner) > > + break; > > + > > + owner = old; > > + } > > Can you rewrite this using atomic_long_fetch_and_release?
Yes, until patch 3/3.. but now that you mention it I think we can do:
owner = atomic_long_read(&lock->owner); if (!(owner & MUTEX_FLAG_HANDOFF)) (void)atomic_long_fetch_and_release(MUTEX_FLAGS, &lock->owner);
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