ehrhardt@xxxxxxxxxxxxxxxxxx wrote:
From: Christian Borntraeger <borntraeger@xxxxxxxxxx>
This patch reworks the s390 clock comparator wakeup to hrtimer. The clock
comparator is a per-cpu value that is compared against the TOD clock. If
ckc <= TOD an external interrupt 1004 is triggered. Since the clock comparator
and the TOD clock have a much higher resolution than jiffies we should use
hrtimers to trigger the wakeup. This speeds up guest nanosleep for small
values.
Since hrtimers callbacks run in hard-irq context, I added a tasklet to do
the actual work with enabled interrupts.
-void kvm_s390_idle_wakeup(unsigned long data)
+void kvm_s390_tasklet(unsigned long parm)
{
- struct kvm_vcpu *vcpu = (struct kvm_vcpu *)data;
+ struct kvm_vcpu *vcpu = (struct kvm_vcpu *) parm;
- spin_lock_bh(&vcpu->arch.local_int.lock);
+ spin_lock(&vcpu->arch.local_int.lock);
vcpu->arch.local_int.timer_due = 1;
if (waitqueue_active(&vcpu->arch.local_int.wq))
wake_up_interruptible(&vcpu->arch.local_int.wq);
- spin_unlock_bh(&vcpu->arch.local_int.lock);
+ spin_unlock(&vcpu->arch.local_int.lock);
}
Why can't this be done from the timer context (after adjusting the locks)?
--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.
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