Re: [PATCH v7 2/3] KVM: dynamic halt-polling

From: Wanpeng Li
Date: Fri Sep 04 2015 - 18:38:55 EST


Hi Paolo,
On 9/3/15 10:07 PM, Wanpeng Li wrote:
[...]
static int kvm_vcpu_check_block(struct kvm_vcpu *vcpu)
{
if (kvm_arch_vcpu_runnable(vcpu)) {
@@ -1928,7 +1962,8 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
{
ktime_t start, cur;
DEFINE_WAIT(wait);
- bool waited = false;
+ bool polled = false, waited = false;
+ u64 poll_ns = 0, wait_ns = 0, block_ns = 0;
start = cur = ktime_get();
if (vcpu->halt_poll_ns) {
@@ -1940,11 +1975,16 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
* arrives.
*/
if (kvm_vcpu_check_block(vcpu) < 0) {
+ polled = true;
++vcpu->stat.halt_successful_poll;
- goto out;
+ break;
}
cur = ktime_get();
} while (single_task_running() && ktime_before(cur, stop));
+
+ poll_ns = ktime_to_ns(cur) - ktime_to_ns(start);
+ if (polled)
+ goto out;


Please move poll_ns caculation under if() when you applied, as I explained in reply to v6.

Regards,
Wanpeng Li
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