Re: [PATCH V2 RFC 2/3] kvm: Handle yield_to failure return code for potential undercommit case

[Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>]

On 10/31/2012 06:08 PM, Avi Kivity wrote:
> On 10/29/2012 04:07 PM, Raghavendra K T wrote:
>> From: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
>>
>> Also we do not update last boosted vcpu in failure cases.
>>
>>   #endif
>> +
>>   void kvm_vcpu_on_spin(struct kvm_vcpu *me)
>>   {
>>   	struct kvm *kvm = me->kvm;
>> @@ -1727,11 +1727,12 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me)
>>   				continue;
>>   			if (!kvm_vcpu_eligible_for_directed_yield(vcpu))
>>   				continue;
>> -			if (kvm_vcpu_yield_to(vcpu)) {
>> +
>> +			yielded = kvm_vcpu_yield_to(vcpu);
>> +			if (yielded > 0)
>>   				kvm->last_boosted_vcpu = i;
>> -				yielded = 1;
>> +			if (yielded)
>>   				break;
>> -			}
>>   		}
>
> If yielded == -ESRCH, should we not try to yield to another vcpu?
>

  Yes. plan is to abort the iteration. since it means we are mostly 
undercommitted.