On Thu, 2013-10-24 at 10:12 -0400, Waiman Long wrote: > On 10/24/2013 06:14 AM, Thomas Gleixner wrote: > > On Wed, 23 Oct 2013, Waiman Long wrote: > >> On 10/23/2013 08:00 AM, walken@xxxxxxxxxx wrote: > >>>> + /* > >>>> + * Wait until the next one in queue set up the next field > >>>> + */ > >>>> + while (likely(!(next = ACCESS_ONCE(node->next)))) > >>>> + cpu_relax(); > >>>> + /* > >>>> + * The next one in queue is now at the head > >>>> + */ > >>>> +notify_next: > >>>> + barrier(); > >>>> + ACCESS_ONCE(next->wait) = false; > >>>> + smp_wmb(); > >>>> +} > >>> I believe this could be unified with mspin_lock() / mspin_unlock() in > >>> kernel/mutex.c ? (there is already talk of extending these functions > >>> to be used by rwsem for adaptive spinning as well...) > >> It probably can, but the unification can wait until the code are in. > > The unification has to be done as a part of this series. Cleanups are > > part of the development process of new code and not an optional > > feature. > > > > Thanks, > > > > tglx > > > > There is an outstanding rwsem patch series that is doing the > unification. I am waiting for that patch series to be at least in a tip > or linux-next branch before doing the unification. Otherwise, it will > cause merge conflict. We can merge the 3 MCS patches of the rwsem patch series first while we continue to work on other rwsem patches. These 3 patches are independent of the other rwsem patches. They separate out the MCS locking into its own file and clean up the code. MCS Lock: Restructure the MCS lock defines and locking https://lkml.org/lkml/2013/10/2/647 MCS Lock: optimizations and extra comments https://lkml.org/lkml/2013/10/2/644 MCS Lock: Barrier corrections https://lkml.org/lkml/2013/10/2/650 Thanks. Tim -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
