Messages in this thread | | | Subject | Re: [PATCH 5/8] locking, mutex: Cancelable MCS lock for adaptive spinning | From | Jason Low <> | Date | Wed, 26 Feb 2014 09:45:25 -0800 |
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On Wed, 2014-02-26 at 10:22 +0100, Peter Zijlstra wrote: > On Tue, Feb 25, 2014 at 11:56:19AM -0800, Jason Low wrote: > > On Mon, 2014-02-10 at 20:58 +0100, Peter Zijlstra wrote: > > > + for (;;) { > > > + if (prev->next == node && > > > + cmpxchg(&prev->next, node, NULL) == node) > > > + break; > > > + > > > + /* > > > + * We can only fail the cmpxchg() racing against an unlock(), > > > + * in which case we should observe @node->locked becomming > > > + * true. > > > + */ > > > + if (smp_load_acquire(&node->locked)) > > > + return true; > > I've stuck on in right about here. So that we don't unduly delay the > cmpxchg() after the load of prev.
Ok.
Reviewed-by: Jason Low <jason.low2@hp.com>
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