KVM: s390: move vcpu wakeup code to a central point
Let's move the vcpu wakeup code to a central point.
We should set the vcpu->preempted flag only if the target is actually sleeping
and before the real wakeup happens. Otherwise the preempted flag might be set,
when not necessary. This may result in immediate reschedules after schedule()
in some scenarios.
The wakeup code doesn't require the local_int.lock to be held.
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index 86575b4..65396e1 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -617,12 +617,22 @@
return 0;
}
+void kvm_s390_vcpu_wakeup(struct kvm_vcpu *vcpu)
+{
+ if (waitqueue_active(&vcpu->wq)) {
+ /*
+ * The vcpu gave up the cpu voluntarily, mark it as a good
+ * yield-candidate.
+ */
+ vcpu->preempted = true;
+ wake_up_interruptible(&vcpu->wq);
+ }
+}
+
void kvm_s390_tasklet(unsigned long parm)
{
struct kvm_vcpu *vcpu = (struct kvm_vcpu *) parm;
-
- if (waitqueue_active(&vcpu->wq))
- wake_up_interruptible(&vcpu->wq);
+ kvm_s390_vcpu_wakeup(vcpu);
}
/*
@@ -905,10 +915,8 @@
li = &dst_vcpu->arch.local_int;
spin_lock(&li->lock);
atomic_set_mask(CPUSTAT_EXT_INT, li->cpuflags);
- if (waitqueue_active(li->wq))
- wake_up_interruptible(li->wq);
- kvm_get_vcpu(kvm, sigcpu)->preempted = true;
spin_unlock(&li->lock);
+ kvm_s390_vcpu_wakeup(kvm_get_vcpu(kvm, sigcpu));
unlock_fi:
spin_unlock(&fi->lock);
mutex_unlock(&kvm->lock);
@@ -1059,11 +1067,9 @@
if (inti->type == KVM_S390_SIGP_STOP)
li->action_bits |= ACTION_STOP_ON_STOP;
atomic_set_mask(CPUSTAT_EXT_INT, li->cpuflags);
- if (waitqueue_active(&vcpu->wq))
- wake_up_interruptible(&vcpu->wq);
- vcpu->preempted = true;
spin_unlock(&li->lock);
mutex_unlock(&vcpu->kvm->lock);
+ kvm_s390_vcpu_wakeup(vcpu);
return 0;
}