linux-kernel - Re: [PATCH] kvm: make vcpu life cycle separated from kvm instance

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Date:	Mon, 5 Dec 2011 13:29:17 +0800
From:	Liu ping fan <kernelfans@...il.com>
To:	Avi Kivity <avi@...hat.com>
Cc:	kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
	aliguori@...ibm.com, gleb@...hat.com, jan.kiszka@....de
Subject: Re: [PATCH] kvm: make vcpu life cycle separated from kvm instance

On Sun, Dec 4, 2011 at 6:23 PM, Avi Kivity <avi@...hat.com> wrote:
> On 12/02/2011 08:26 AM, Liu Ping Fan wrote:
>> From: Liu Ping Fan <pingfank@...ux.vnet.ibm.com>
>>
>> Currently, vcpu can be destructed only when kvm instance destroyed.
>> Change this to vcpu's destruction taken when its refcnt is zero,
>> and then vcpu MUST and CAN be destroyed before kvm's destroy.
>>
>>
>> @@ -315,9 +315,17 @@ static void pit_do_work(struct work_struct *work)
>>                * LVT0 to NMI delivery. Other PIC interrupts are just sent to
>>                * VCPU0, and only if its LVT0 is in EXTINT mode.
>>                */
>> -             if (kvm->arch.vapics_in_nmi_mode > 0)
>> -                     kvm_for_each_vcpu(i, vcpu, kvm)
>> +             if (kvm->arch.vapics_in_nmi_mode > 0) {
>> +                     rcu_read_lock();
>> +                     kvm_for_each_vcpu(i, cnt, vcpu, kvm) {
>> +                             vcpu = kvm_get_vcpu(kvm, i);
>> +                             if (vcpu == NULL)
>> +                                     continue;
>> +                             cnt++;
>>                               kvm_apic_nmi_wd_deliver(vcpu);
>> +                     }
>> +                     rcu_read_unlock();
>> +             }
>>       }
>>  }
>
> This pattern keeps repeating, please fold it into kvm_for_each_vcpu().
>
What about folding
kvm_for_each_vcpu(i, cnt, vcpu, kvm) {
              vcpu = kvm_get_vcpu(kvm, i);
              if (vcpu == NULL)
                        continue;
              cnt++;

like this,
#define kvm_for_each_vcpu(idx, cnt, vcpup, kvm) \
	for (idx = 0, cnt = 0, vcpup = kvm_get_vcpu(kvm, idx); \
	     cnt < atomic_read(&kvm->online_vcpus) && \
	     idx < KVM_MAX_VCPUS; \
	     idx++, (vcpup == NULL)?:cnt++, vcpup = kvm_get_vcpu(kvm, idx)) \
	     if (vcpup == NULL) \
	          continue; \
	     else


A little ugly, but have not thought a better way out :-)

Thanks,
ping fan
> --
> error compiling committee.c: too many arguments to function
>