On Mon, Jun 27, 2016 at 04:00:43PM +0200, Peter Zijlstra wrote:

On Mon, Jun 27, 2016 at 01:41:28PM -0400, Pan Xinhui wrote:

quoted

+++ b/include/linux/sched.h

@@ -3293,6 +3293,15 @@ static inline void set_task_cpu(struct task_struct *p, unsigned int cpu)
 
 #endif /* CONFIG_SMP */
 
+#ifdef arch_vcpu_is_preempted
+static inline bool vcpu_is_preempted(int cpu)
+{
+	return arch_vcpu_is_preempted(cpu);
+}
+#else
+#define vcpu_is_preempted(cpu)	false
+#endif

#ifndef vcpu_is_preempted
#define vcpu_is_preempted(cpu)		(false)
#endif

Is so much simpler...

Also, please Cc the virt list so that other interested parties can
comment, and maybe also the s390 folks.

And before you hurry off to post again, add a patch doing
mutex_spin_on_owner() and rwsem_spin_in_owner().