Re: [PATCH v4 3/3] KVM: X86: Don't use PV TLB flush with dedicated vCPUs and steal time disabled

2018-02-13 Thread Wanpeng Li 
2018-02-14 0:12 GMT+08:00 Paolo Bonzini :
> On 13/02/2018 02:05, Wanpeng Li wrote:
>> From: Wanpeng Li 
>>
>> vCPUs are very unlikely to get preempted when they are the only task
>> running on a CPU.  PV TLB flush is slower that the native flush in that
>> case. In addition, avoid traversing all the cpus for pv tlb flush when
>> steal time is disabled since pv tlb flush depends on the field in steal
>> time for shared data.
>>
>> Cc: Paolo Bonzini 
>> Cc: Radim Krčmář 
>> Cc: Eduardo Habkost 
>> Signed-off-by: Wanpeng Li 
>> ---
>>  arch/x86/kernel/kvm.c | 8 ++--
>>  1 file changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
>> index c5566d9..285822f 100644
>> --- a/arch/x86/kernel/kvm.c
>> +++ b/arch/x86/kernel/kvm.c
>> @@ -545,7 +545,9 @@ static void __init kvm_guest_init(void)
>>   pv_time_ops.steal_clock = kvm_steal_clock;
>>   }
>>
>> - if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH))
>> + if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
>> + !kvm_para_has_feature(KVM_HINTS_DEDICATED) &&
>> + !kvm_para_has_feature(KVM_FEATURE_STEAL_TIME))
>>   pv_mmu_ops.flush_tlb_others = kvm_flush_tlb_others;
>>
>>   if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
>> @@ -638,7 +640,9 @@ static __init int kvm_setup_pv_tlb_flush(void)
>>  {
>>   int cpu;
>>
>> - if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH)) {
>> + if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
>> + !kvm_para_has_feature(KVM_HINTS_DEDICATED) &&
>
> This should have checked the hints word.
>
> In general, I'm going to change in the whole series
> kvm_hint_has_feature with kvm_para_has_hint, and kvm_arch_hint_features
> with kvm_arch_para_hints.  But apart from this small naming issue, the
> series looks good, and I'm applying it to kvm/queue.

Thanks Paolo.

Regards,
Wanpeng Li

Re: [PATCH v4 3/3] KVM: X86: Don't use PV TLB flush with dedicated vCPUs and steal time disabled

2018-02-13 Thread Wanpeng Li 
2018-02-14 0:12 GMT+08:00 Paolo Bonzini :
> On 13/02/2018 02:05, Wanpeng Li wrote:
>> From: Wanpeng Li 
>>
>> vCPUs are very unlikely to get preempted when they are the only task
>> running on a CPU.  PV TLB flush is slower that the native flush in that
>> case. In addition, avoid traversing all the cpus for pv tlb flush when
>> steal time is disabled since pv tlb flush depends on the field in steal
>> time for shared data.
>>
>> Cc: Paolo Bonzini 
>> Cc: Radim Krčmář 
>> Cc: Eduardo Habkost 
>> Signed-off-by: Wanpeng Li 
>> ---
>>  arch/x86/kernel/kvm.c | 8 ++--
>>  1 file changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
>> index c5566d9..285822f 100644
>> --- a/arch/x86/kernel/kvm.c
>> +++ b/arch/x86/kernel/kvm.c
>> @@ -545,7 +545,9 @@ static void __init kvm_guest_init(void)
>>   pv_time_ops.steal_clock = kvm_steal_clock;
>>   }
>>
>> - if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH))
>> + if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
>> + !kvm_para_has_feature(KVM_HINTS_DEDICATED) &&
>> + !kvm_para_has_feature(KVM_FEATURE_STEAL_TIME))
>>   pv_mmu_ops.flush_tlb_others = kvm_flush_tlb_others;
>>
>>   if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
>> @@ -638,7 +640,9 @@ static __init int kvm_setup_pv_tlb_flush(void)
>>  {
>>   int cpu;
>>
>> - if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH)) {
>> + if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
>> + !kvm_para_has_feature(KVM_HINTS_DEDICATED) &&
>
> This should have checked the hints word.
>
> In general, I'm going to change in the whole series
> kvm_hint_has_feature with kvm_para_has_hint, and kvm_arch_hint_features
> with kvm_arch_para_hints.  But apart from this small naming issue, the
> series looks good, and I'm applying it to kvm/queue.

Thanks Paolo.

Regards,
Wanpeng Li

Re: [PATCH v4 3/3] KVM: X86: Don't use PV TLB flush with dedicated vCPUs and steal time disabled

2018-02-13 Thread Paolo Bonzini 
On 13/02/2018 02:05, Wanpeng Li wrote:
> From: Wanpeng Li 
> 
> vCPUs are very unlikely to get preempted when they are the only task
> running on a CPU.  PV TLB flush is slower that the native flush in that
> case. In addition, avoid traversing all the cpus for pv tlb flush when
> steal time is disabled since pv tlb flush depends on the field in steal
> time for shared data.
> 
> Cc: Paolo Bonzini 
> Cc: Radim Krčmář 
> Cc: Eduardo Habkost 
> Signed-off-by: Wanpeng Li 
> ---
>  arch/x86/kernel/kvm.c | 8 ++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
> index c5566d9..285822f 100644
> --- a/arch/x86/kernel/kvm.c
> +++ b/arch/x86/kernel/kvm.c
> @@ -545,7 +545,9 @@ static void __init kvm_guest_init(void)
>   pv_time_ops.steal_clock = kvm_steal_clock;
>   }
>  
> - if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH))
> + if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
> + !kvm_para_has_feature(KVM_HINTS_DEDICATED) &&
> + !kvm_para_has_feature(KVM_FEATURE_STEAL_TIME))
>   pv_mmu_ops.flush_tlb_others = kvm_flush_tlb_others;
>  
>   if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
> @@ -638,7 +640,9 @@ static __init int kvm_setup_pv_tlb_flush(void)
>  {
>   int cpu;
>  
> - if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH)) {
> + if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
> + !kvm_para_has_feature(KVM_HINTS_DEDICATED) &&

This should have checked the hints word.

In general, I'm going to change in the whole series
kvm_hint_has_feature with kvm_para_has_hint, and kvm_arch_hint_features
with kvm_arch_para_hints.  But apart from this small naming issue, the
series looks good, and I'm applying it to kvm/queue.

Paolo

> + !kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
>   for_each_possible_cpu(cpu) {
>   zalloc_cpumask_var_node(per_cpu_ptr(&__pv_tlb_mask, 
> cpu),
>   GFP_KERNEL, cpu_to_node(cpu));
>

Re: [PATCH v4 3/3] KVM: X86: Don't use PV TLB flush with dedicated vCPUs and steal time disabled

2018-02-13 Thread Paolo Bonzini 
On 13/02/2018 02:05, Wanpeng Li wrote:
> From: Wanpeng Li 
> 
> vCPUs are very unlikely to get preempted when they are the only task
> running on a CPU.  PV TLB flush is slower that the native flush in that
> case. In addition, avoid traversing all the cpus for pv tlb flush when
> steal time is disabled since pv tlb flush depends on the field in steal
> time for shared data.
> 
> Cc: Paolo Bonzini 
> Cc: Radim Krčmář 
> Cc: Eduardo Habkost 
> Signed-off-by: Wanpeng Li 
> ---
>  arch/x86/kernel/kvm.c | 8 ++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
> index c5566d9..285822f 100644
> --- a/arch/x86/kernel/kvm.c
> +++ b/arch/x86/kernel/kvm.c
> @@ -545,7 +545,9 @@ static void __init kvm_guest_init(void)
>   pv_time_ops.steal_clock = kvm_steal_clock;
>   }
>  
> - if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH))
> + if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
> + !kvm_para_has_feature(KVM_HINTS_DEDICATED) &&
> + !kvm_para_has_feature(KVM_FEATURE_STEAL_TIME))
>   pv_mmu_ops.flush_tlb_others = kvm_flush_tlb_others;
>  
>   if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
> @@ -638,7 +640,9 @@ static __init int kvm_setup_pv_tlb_flush(void)
>  {
>   int cpu;
>  
> - if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH)) {
> + if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
> + !kvm_para_has_feature(KVM_HINTS_DEDICATED) &&

This should have checked the hints word.

In general, I'm going to change in the whole series
kvm_hint_has_feature with kvm_para_has_hint, and kvm_arch_hint_features
with kvm_arch_para_hints.  But apart from this small naming issue, the
series looks good, and I'm applying it to kvm/queue.

Paolo

> + !kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
>   for_each_possible_cpu(cpu) {
>   zalloc_cpumask_var_node(per_cpu_ptr(&__pv_tlb_mask, 
> cpu),
>   GFP_KERNEL, cpu_to_node(cpu));
>

[PATCH v4 3/3] KVM: X86: Don't use PV TLB flush with dedicated vCPUs and steal time disabled

2018-02-12 Thread Wanpeng Li 
From: Wanpeng Li 

vCPUs are very unlikely to get preempted when they are the only task
running on a CPU.  PV TLB flush is slower that the native flush in that
case. In addition, avoid traversing all the cpus for pv tlb flush when
steal time is disabled since pv tlb flush depends on the field in steal
time for shared data.

Cc: Paolo Bonzini 
Cc: Radim Krčmář 
Cc: Eduardo Habkost 
Signed-off-by: Wanpeng Li 
---
 arch/x86/kernel/kvm.c | 8 ++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index c5566d9..285822f 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -545,7 +545,9 @@ static void __init kvm_guest_init(void)
pv_time_ops.steal_clock = kvm_steal_clock;
}
 
-   if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH))
+   if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
+   !kvm_para_has_feature(KVM_HINTS_DEDICATED) &&
+   !kvm_para_has_feature(KVM_FEATURE_STEAL_TIME))
pv_mmu_ops.flush_tlb_others = kvm_flush_tlb_others;
 
if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
@@ -638,7 +640,9 @@ static __init int kvm_setup_pv_tlb_flush(void)
 {
int cpu;
 
-   if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH)) {
+   if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
+   !kvm_para_has_feature(KVM_HINTS_DEDICATED) &&
+   !kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
for_each_possible_cpu(cpu) {
zalloc_cpumask_var_node(per_cpu_ptr(&__pv_tlb_mask, 
cpu),
GFP_KERNEL, cpu_to_node(cpu));
-- 
2.7.4

[PATCH v4 3/3] KVM: X86: Don't use PV TLB flush with dedicated vCPUs and steal time disabled

2018-02-12 Thread Wanpeng Li 
From: Wanpeng Li 

vCPUs are very unlikely to get preempted when they are the only task
running on a CPU.  PV TLB flush is slower that the native flush in that
case. In addition, avoid traversing all the cpus for pv tlb flush when
steal time is disabled since pv tlb flush depends on the field in steal
time for shared data.

Cc: Paolo Bonzini 
Cc: Radim Krčmář 
Cc: Eduardo Habkost 
Signed-off-by: Wanpeng Li 
---
 arch/x86/kernel/kvm.c | 8 ++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index c5566d9..285822f 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -545,7 +545,9 @@ static void __init kvm_guest_init(void)
pv_time_ops.steal_clock = kvm_steal_clock;
}
 
-   if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH))
+   if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
+   !kvm_para_has_feature(KVM_HINTS_DEDICATED) &&
+   !kvm_para_has_feature(KVM_FEATURE_STEAL_TIME))
pv_mmu_ops.flush_tlb_others = kvm_flush_tlb_others;
 
if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
@@ -638,7 +640,9 @@ static __init int kvm_setup_pv_tlb_flush(void)
 {
int cpu;
 
-   if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH)) {
+   if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
+   !kvm_para_has_feature(KVM_HINTS_DEDICATED) &&
+   !kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
for_each_possible_cpu(cpu) {
zalloc_cpumask_var_node(per_cpu_ptr(&__pv_tlb_mask, 
cpu),
GFP_KERNEL, cpu_to_node(cpu));
-- 
2.7.4