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KVM: s390: move vcpu wakeup code to a central point

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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>
This commit is contained in:
David Hildenbrand
2014-05-16 11:59:46 +02:00
committed by Christian Borntraeger
parent 433b9ee43c
commit 0e9c85a5a3
3 changed files with 22 additions and 23 deletions
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24
arch/s390/kvm/interrupt.c
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@@ -617,12 +617,22 @@ no_timer:
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 @@ static int __inject_vm(struct kvm *kvm, struct kvm_s390_interrupt_info *inti)
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 @@ int kvm_s390_inject_vcpu(struct kvm_vcpu *vcpu,
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;
}