diff mbox series

[v7,3/4] KVM: arm64: Dirty quota-based throttling of vcpus

Message ID 20221113170507.208810-4-shivam.kumar1@nutanix.com (mailing list archive)
State New, archived
Headers show
Series KVM: Dirty quota-based throttling | expand

Commit Message

Shivam Kumar Nov. 13, 2022, 5:05 p.m. UTC 
Exit to userspace whenever the dirty quota is exhausted (i.e. dirty count
equals/exceeds dirty quota) to request more dirty quota.

Suggested-by: Shaju Abraham <shaju.abraham@nutanix.com>
Suggested-by: Manish Mishra <manish.mishra@nutanix.com>
Co-developed-by: Anurag Madnawat <anurag.madnawat@nutanix.com>
Signed-off-by: Anurag Madnawat <anurag.madnawat@nutanix.com>
Signed-off-by: Shivam Kumar <shivam.kumar1@nutanix.com>
---
 arch/arm64/kvm/arm.c | 9 +++++++++
 1 file changed, 9 insertions(+)

Comments

Yunhong Jiang Nov. 15, 2022, 12:27 a.m. UTC | #1 
On Sun, Nov 13, 2022 at 05:05:10PM +0000, Shivam Kumar wrote:
> Exit to userspace whenever the dirty quota is exhausted (i.e. dirty count
> equals/exceeds dirty quota) to request more dirty quota.
> 
> Suggested-by: Shaju Abraham <shaju.abraham@nutanix.com>
> Suggested-by: Manish Mishra <manish.mishra@nutanix.com>
> Co-developed-by: Anurag Madnawat <anurag.madnawat@nutanix.com>
> Signed-off-by: Anurag Madnawat <anurag.madnawat@nutanix.com>
> Signed-off-by: Shivam Kumar <shivam.kumar1@nutanix.com>
> ---
>  arch/arm64/kvm/arm.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index 94d33e296e10..850024982dd9 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -746,6 +746,15 @@ static int check_vcpu_requests(struct kvm_vcpu *vcpu)
>  
>  		if (kvm_check_request(KVM_REQ_SUSPEND, vcpu))
>  			return kvm_vcpu_suspend(vcpu);
> +
> +		if (kvm_check_request(KVM_REQ_DIRTY_QUOTA_EXIT, vcpu)) {
> +			struct kvm_run *run = vcpu->run;
> +
> +			run->exit_reason = KVM_EXIT_DIRTY_QUOTA_EXHAUSTED;
> +			run->dirty_quota_exit.count = vcpu->stat.generic.pages_dirtied;
> +			run->dirty_quota_exit.quota = vcpu->dirty_quota;
> +			return 0;
> +		}
There is a recheck on x86 side, but not here. Any architecture specific reason?
Sorry if I missed anything.

BTW, not sure if the x86/arm code can be combined into a common function. I
don't see any architecture specific code here.
Shivam Kumar Nov. 15, 2022, 5:10 a.m. UTC | #2 
On 15/11/22 5:57 am, Yunhong Jiang wrote:
> On Sun, Nov 13, 2022 at 05:05:10PM +0000, Shivam Kumar wrote:
>> Exit to userspace whenever the dirty quota is exhausted (i.e. dirty count
>> equals/exceeds dirty quota) to request more dirty quota.
>>
>> Suggested-by: Shaju Abraham <shaju.abraham@nutanix.com>
>> Suggested-by: Manish Mishra <manish.mishra@nutanix.com>
>> Co-developed-by: Anurag Madnawat <anurag.madnawat@nutanix.com>
>> Signed-off-by: Anurag Madnawat <anurag.madnawat@nutanix.com>
>> Signed-off-by: Shivam Kumar <shivam.kumar1@nutanix.com>
>> ---
>>   arch/arm64/kvm/arm.c | 9 +++++++++
>>   1 file changed, 9 insertions(+)
>>
>> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
>> index 94d33e296e10..850024982dd9 100644
>> --- a/arch/arm64/kvm/arm.c
>> +++ b/arch/arm64/kvm/arm.c
>> @@ -746,6 +746,15 @@ static int check_vcpu_requests(struct kvm_vcpu *vcpu)
>>   
>>   		if (kvm_check_request(KVM_REQ_SUSPEND, vcpu))
>>   			return kvm_vcpu_suspend(vcpu);
>> +
>> +		if (kvm_check_request(KVM_REQ_DIRTY_QUOTA_EXIT, vcpu)) {
>> +			struct kvm_run *run = vcpu->run;
>> +
>> +			run->exit_reason = KVM_EXIT_DIRTY_QUOTA_EXHAUSTED;
>> +			run->dirty_quota_exit.count = vcpu->stat.generic.pages_dirtied;
>> +			run->dirty_quota_exit.quota = vcpu->dirty_quota;
>> +			return 0;
>> +		}
> There is a recheck on x86 side, but not here. Any architecture specific reason?
> Sorry if I missed anything.
> 
> BTW, not sure if the x86/arm code can be combined into a common function. I
> don't see any architecture specific code here.
Yes, I think we may use a common function for x86/arm.

With that, this would look like:

if (kvm_check_dirty_quota_request(vcpu)) {
	return 0;
}

Thanks,
Shivam
Marc Zyngier Nov. 17, 2022, 8:44 p.m. UTC | #3 
On Sun, 13 Nov 2022 17:05:10 +0000,
Shivam Kumar <shivam.kumar1@nutanix.com> wrote:
> 
> Exit to userspace whenever the dirty quota is exhausted (i.e. dirty count
> equals/exceeds dirty quota) to request more dirty quota.
> 
> Suggested-by: Shaju Abraham <shaju.abraham@nutanix.com>
> Suggested-by: Manish Mishra <manish.mishra@nutanix.com>
> Co-developed-by: Anurag Madnawat <anurag.madnawat@nutanix.com>
> Signed-off-by: Anurag Madnawat <anurag.madnawat@nutanix.com>
> Signed-off-by: Shivam Kumar <shivam.kumar1@nutanix.com>
> ---
>  arch/arm64/kvm/arm.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index 94d33e296e10..850024982dd9 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -746,6 +746,15 @@ static int check_vcpu_requests(struct kvm_vcpu *vcpu)
>  
>  		if (kvm_check_request(KVM_REQ_SUSPEND, vcpu))
>  			return kvm_vcpu_suspend(vcpu);
> +
> +		if (kvm_check_request(KVM_REQ_DIRTY_QUOTA_EXIT, vcpu)) {
> +			struct kvm_run *run = vcpu->run;
> +
> +			run->exit_reason = KVM_EXIT_DIRTY_QUOTA_EXHAUSTED;
> +			run->dirty_quota_exit.count = vcpu->stat.generic.pages_dirtied;
> +			run->dirty_quota_exit.quota = vcpu->dirty_quota;
> +			return 0;
> +		}
>  	}
>  
>  	return 1;

As pointed out by others, this should be common code. This would
definitely avoid the difference in behaviour between architectures.

	M.
Shivam Kumar Nov. 18, 2022, 8:56 a.m. UTC | #4 
On 18/11/22 2:14 am, Marc Zyngier wrote:
> On Sun, 13 Nov 2022 17:05:10 +0000,
> Shivam Kumar <shivam.kumar1@nutanix.com> wrote:
>>
>> Exit to userspace whenever the dirty quota is exhausted (i.e. dirty count
>> equals/exceeds dirty quota) to request more dirty quota.
>>
>> Suggested-by: Shaju Abraham <shaju.abraham@nutanix.com>
>> Suggested-by: Manish Mishra <manish.mishra@nutanix.com>
>> Co-developed-by: Anurag Madnawat <anurag.madnawat@nutanix.com>
>> Signed-off-by: Anurag Madnawat <anurag.madnawat@nutanix.com>
>> Signed-off-by: Shivam Kumar <shivam.kumar1@nutanix.com>
>> ---
>>   arch/arm64/kvm/arm.c | 9 +++++++++
>>   1 file changed, 9 insertions(+)
>>
>> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
>> index 94d33e296e10..850024982dd9 100644
>> --- a/arch/arm64/kvm/arm.c
>> +++ b/arch/arm64/kvm/arm.c
>> @@ -746,6 +746,15 @@ static int check_vcpu_requests(struct kvm_vcpu *vcpu)
>>   
>>   		if (kvm_check_request(KVM_REQ_SUSPEND, vcpu))
>>   			return kvm_vcpu_suspend(vcpu);
>> +
>> +		if (kvm_check_request(KVM_REQ_DIRTY_QUOTA_EXIT, vcpu)) {
>> +			struct kvm_run *run = vcpu->run;
>> +
>> +			run->exit_reason = KVM_EXIT_DIRTY_QUOTA_EXHAUSTED;
>> +			run->dirty_quota_exit.count = vcpu->stat.generic.pages_dirtied;
>> +			run->dirty_quota_exit.quota = vcpu->dirty_quota;
>> +			return 0;
>> +		}
>>   	}
>>   
>>   	return 1;
> 
> As pointed out by others, this should be common code. This would
> definitely avoid the difference in behaviour between architectures.
> 
> 	M.
> 
Ack.

Thanks,
Shivam
diff mbox series

Patch

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 94d33e296e10..850024982dd9 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -746,6 +746,15 @@  static int check_vcpu_requests(struct kvm_vcpu *vcpu)
 
 		if (kvm_check_request(KVM_REQ_SUSPEND, vcpu))
 			return kvm_vcpu_suspend(vcpu);
+
+		if (kvm_check_request(KVM_REQ_DIRTY_QUOTA_EXIT, vcpu)) {
+			struct kvm_run *run = vcpu->run;
+
+			run->exit_reason = KVM_EXIT_DIRTY_QUOTA_EXHAUSTED;
+			run->dirty_quota_exit.count = vcpu->stat.generic.pages_dirtied;
+			run->dirty_quota_exit.quota = vcpu->dirty_quota;
+			return 0;
+		}
 	}
 
 	return 1;