On 9/3/15 2:09 AM, David Matlack wrote:
[...]
+
static int kvm_vcpu_check_block(struct kvm_vcpu *vcpu)
{
if (kvm_arch_vcpu_runnable(vcpu)) {
@@ -1929,6 +1963,7 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
ktime_t start, cur;
DEFINE_WAIT(wait);
bool waited = false;
+ u64 poll_ns = 0, wait_ns = 0, block_ns = 0;
start = cur = ktime_get();
if (vcpu->halt_poll_ns) {
@@ -1941,10 +1976,15 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
*/
if (kvm_vcpu_check_block(vcpu) < 0) {
++vcpu->stat.halt_successful_poll;
- goto out;
+ break;
}
cur = ktime_get();
} while (single_task_running() && ktime_before(cur, stop));
+
+ if (ktime_before(cur, stop)) {
You can't use 'cur' to tell if the interrupt arrived. single_task_running()
can break us out of the loop before 'stop'.
+ poll_ns = ktime_to_ns(cur) - ktime_to_ns(start);
Put this line before the if(). block_ns should always include the time
spent polling; even if polling does not succeed.
How about something like:
@@ -1941,10 +1976,14 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
*/
if (kvm_vcpu_check_block(vcpu) < 0) {
++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 (ktime_before(cur, stop) && single_task_running())
+ goto out;
}
+ goto out;
+ }
}
for (;;) {
@@ -1959,9 +1999,24 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
finish_wait(&vcpu->wq, &wait);
cur = ktime_get();
+ wait_ns = ktime_to_ns(cur) - ktime_to_ns(start);
out:
- trace_kvm_vcpu_wakeup(ktime_to_ns(cur) - ktime_to_ns(start), waited);
+ block_ns = poll_ns + wait_ns;
+
+ if (halt_poll_ns) {
If you want, you can leave this if() out and save some indentation.
Then we will miss the tracepoint.
Regards,
Wanpeng Li
+ if (block_ns <= vcpu->halt_poll_ns)
+ ;
+ /* we had a long block, shrink polling */
+ else if (vcpu->halt_poll_ns && block_ns > halt_poll_ns)
+ shrink_halt_poll_ns(vcpu);
+ /* we had a short halt and our poll time is too small */
+ else if (vcpu->halt_poll_ns < halt_poll_ns &&
+ block_ns < halt_poll_ns)
+ grow_halt_poll_ns(vcpu);
+ }
+
+ trace_kvm_vcpu_wakeup(block_ns, waited);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_block);
--
1.9.1
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
