On Fri, Nov 06, 2015 at 12:47:49PM -0500, Waiman Long wrote: > On 11/06/2015 09:50 AM, Peter Zijlstra wrote: > >*urgh*, last time we had: > > > >+ if (pv_wait_head_or_steal()) > >+ goto stolen; > > while ((val = smp_load_acquire(&lock->val.counter))& > > _Q_LOCKED_PENDING_MASK) > > cpu_relax(); > > > > ... > > > >+stolen: > > while (!(next = READ_ONCE(node->next))) > > cpu_relax(); > > > > ... > > > >Now you completely overhaul the native code.. what happened? > > I want to reuse as much of the existing native code as possible instead of > duplicating that in the PV function. The only difference now is that the PV > function will acquire that lock.
Right; and while I doubt it hurts the native case (you did benchmark it I hope), I'm not too keen on the end result code wise. Maybe just keep the above. > Semantically, I don't want to call the lock > acquisition as lock stealing as the queue head is entitled to get the lock > next. Fair enough I suppose, pv_wait_head_or_lock() then? > I can rename pv_queued_spin_trylock_unfair() to > pv_queued_spin_steal_lock() to emphasize the fact that this is the routine > where lock stealing happens. OK. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
