diff mbox series

[v2,1/3] context_tracking: Split guest_enter/exit_irqoff

Message ID 1618298169-3831-2-git-send-email-wanpengli@tencent.com (mailing list archive)
State New, archived
Headers show
Series KVM: Properly account for guest CPU time | expand

Commit Message

Wanpeng Li April 13, 2021, 7:16 a.m. UTC 
From: Wanpeng Li <wanpengli@tencent.com>

Split context_tracking part from guest_enter/exit_irqoff, it will be 
called separately in later patches.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
---
 include/linux/context_tracking.h | 42 +++++++++++++++++++++++++++++-----------
 1 file changed, 31 insertions(+), 11 deletions(-)

Comments

Christian Borntraeger April 13, 2021, 7:35 a.m. UTC | #1 
On 13.04.21 09:16, Wanpeng Li wrote:
[...]

> @@ -145,6 +155,13 @@ static __always_inline void guest_exit_irqoff(void)
>   }
> 
>   #else
> +static __always_inline void context_guest_enter_irqoff(void)
> +{
> +	instrumentation_begin();
> +	rcu_virt_note_context_switch(smp_processor_id());
> +	instrumentation_end();
> +}
> +
>   static __always_inline void guest_enter_irqoff(void)
>   {
>   	/*
> @@ -155,10 +172,13 @@ static __always_inline void guest_enter_irqoff(void)
>   	instrumentation_begin();
>   	vtime_account_kernel(current);
>   	current->flags |= PF_VCPU;
> -	rcu_virt_note_context_switch(smp_processor_id());
>   	instrumentation_end();
> +
> +	context_guest_enter_irqoff();

So we now do instrumentation_begin 2 times?
Wanpeng Li April 13, 2021, 7:38 a.m. UTC | #2 
On Tue, 13 Apr 2021 at 15:35, Christian Borntraeger
<borntraeger@de.ibm.com> wrote:
>
>
>
> On 13.04.21 09:16, Wanpeng Li wrote:
> [...]
>
> > @@ -145,6 +155,13 @@ static __always_inline void guest_exit_irqoff(void)
> >   }
> >
> >   #else
> > +static __always_inline void context_guest_enter_irqoff(void)
> > +{
> > +     instrumentation_begin();
> > +     rcu_virt_note_context_switch(smp_processor_id());
> > +     instrumentation_end();
> > +}
> > +
> >   static __always_inline void guest_enter_irqoff(void)
> >   {
> >       /*
> > @@ -155,10 +172,13 @@ static __always_inline void guest_enter_irqoff(void)
> >       instrumentation_begin();
> >       vtime_account_kernel(current);
> >       current->flags |= PF_VCPU;
> > -     rcu_virt_note_context_switch(smp_processor_id());
> >       instrumentation_end();
> > +
> > +     context_guest_enter_irqoff();
>
> So we now do instrumentation_begin 2 times?

Similar to context_guest_enter_irqoff() ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN.

    Wanpeng
Christian Borntraeger April 13, 2021, 7:48 a.m. UTC | #3 
On 13.04.21 09:38, Wanpeng Li wrote:
> On Tue, 13 Apr 2021 at 15:35, Christian Borntraeger
> <borntraeger@de.ibm.com> wrote:
>>
>>
>>
>> On 13.04.21 09:16, Wanpeng Li wrote:
>> [...]
>>
>>> @@ -145,6 +155,13 @@ static __always_inline void guest_exit_irqoff(void)
>>>    }
>>>
>>>    #else
THis is the else part


>>> +static __always_inline void context_guest_enter_irqoff(void)
>>> +{
>>> +     instrumentation_begin();

2nd on
>>> +     rcu_virt_note_context_switch(smp_processor_id());
>>> +     instrumentation_end();
2nd off
>>> +}
>>> +
>>>    static __always_inline void guest_enter_irqoff(void)
>>>    {
>>>        /*
>>> @@ -155,10 +172,13 @@ static __always_inline void guest_enter_irqoff(void)
>>>        instrumentation_begin();

first on
>>>        vtime_account_kernel(current);
>>>        current->flags |= PF_VCPU;
>>> -     rcu_virt_note_context_switch(smp_processor_id());
>>>        instrumentation_end();

first off
>>> +
>>> +     context_guest_enter_irqoff();
here we call the 2nd on and off.
>>
>> So we now do instrumentation_begin 2 times?
> 
> Similar to context_guest_enter_irqoff() ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN.

For the
ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN part
context_guest_enter_irqoff()
does not have instrumentation_begin/end.

Or did I miss anything.
Wanpeng Li April 13, 2021, 7:52 a.m. UTC | #4 
On Tue, 13 Apr 2021 at 15:48, Christian Borntraeger
<borntraeger@de.ibm.com> wrote:
>
>
>
> On 13.04.21 09:38, Wanpeng Li wrote:
> > On Tue, 13 Apr 2021 at 15:35, Christian Borntraeger
> > <borntraeger@de.ibm.com> wrote:
> >>
> >>
> >>
> >> On 13.04.21 09:16, Wanpeng Li wrote:
> >> [...]
> >>
> >>> @@ -145,6 +155,13 @@ static __always_inline void guest_exit_irqoff(void)
> >>>    }
> >>>
> >>>    #else
> THis is the else part
>
>
> >>> +static __always_inline void context_guest_enter_irqoff(void)
> >>> +{
> >>> +     instrumentation_begin();
>
> 2nd on
> >>> +     rcu_virt_note_context_switch(smp_processor_id());
> >>> +     instrumentation_end();
> 2nd off
> >>> +}
> >>> +
> >>>    static __always_inline void guest_enter_irqoff(void)
> >>>    {
> >>>        /*
> >>> @@ -155,10 +172,13 @@ static __always_inline void guest_enter_irqoff(void)
> >>>        instrumentation_begin();
>
> first on
> >>>        vtime_account_kernel(current);
> >>>        current->flags |= PF_VCPU;
> >>> -     rcu_virt_note_context_switch(smp_processor_id());
> >>>        instrumentation_end();
>
> first off
> >>> +
> >>> +     context_guest_enter_irqoff();
> here we call the 2nd on and off.
> >>
> >> So we now do instrumentation_begin 2 times?
> >
> > Similar to context_guest_enter_irqoff() ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN.
>
> For the
> ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN part
> context_guest_enter_irqoff()
> does not have instrumentation_begin/end.
>
> Or did I miss anything.

I mean the if (!context_tracking_enabled_this_cpu()) part in the
function context_guest_enter_irqoff() ifdef
CONFIG_VIRT_CPU_ACCOUNTING_GEN. :)

    Wanpeng
Christian Borntraeger April 13, 2021, 8:07 a.m. UTC | #5 
On 13.04.21 09:52, Wanpeng Li wrote:
>> Or did I miss anything.
> 
> I mean the if (!context_tracking_enabled_this_cpu()) part in the
> function context_guest_enter_irqoff() ifdef
> CONFIG_VIRT_CPU_ACCOUNTING_GEN. :)

Ah I missed that. Thanks.
diff mbox series

Patch

diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h
index bceb064..d8ad844 100644
--- a/include/linux/context_tracking.h
+++ b/include/linux/context_tracking.h
@@ -104,16 +104,8 @@  static inline void context_tracking_init(void) { }
 
 
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
-/* must be called with irqs disabled */
-static __always_inline void guest_enter_irqoff(void)
+static __always_inline void context_guest_enter_irqoff(void)
 {
-	instrumentation_begin();
-	if (vtime_accounting_enabled_this_cpu())
-		vtime_guest_enter(current);
-	else
-		current->flags |= PF_VCPU;
-	instrumentation_end();
-
 	if (context_tracking_enabled())
 		__context_tracking_enter(CONTEXT_GUEST);
 
@@ -131,10 +123,28 @@  static __always_inline void guest_enter_irqoff(void)
 	}
 }
 
-static __always_inline void guest_exit_irqoff(void)
+/* must be called with irqs disabled */
+static __always_inline void guest_enter_irqoff(void)
+{
+	instrumentation_begin();
+	if (vtime_accounting_enabled_this_cpu())
+		vtime_guest_enter(current);
+	else
+		current->flags |= PF_VCPU;
+	instrumentation_end();
+
+	context_guest_enter_irqoff();
+}
+
+static __always_inline void context_guest_exit_irqoff(void)
 {
 	if (context_tracking_enabled())
 		__context_tracking_exit(CONTEXT_GUEST);
+}
+
+static __always_inline void guest_exit_irqoff(void)
+{
+	context_guest_exit_irqoff();
 
 	instrumentation_begin();
 	if (vtime_accounting_enabled_this_cpu())
@@ -145,6 +155,13 @@  static __always_inline void guest_exit_irqoff(void)
 }
 
 #else
+static __always_inline void context_guest_enter_irqoff(void)
+{
+	instrumentation_begin();
+	rcu_virt_note_context_switch(smp_processor_id());
+	instrumentation_end();
+}
+
 static __always_inline void guest_enter_irqoff(void)
 {
 	/*
@@ -155,10 +172,13 @@  static __always_inline void guest_enter_irqoff(void)
 	instrumentation_begin();
 	vtime_account_kernel(current);
 	current->flags |= PF_VCPU;
-	rcu_virt_note_context_switch(smp_processor_id());
 	instrumentation_end();
+
+	context_guest_enter_irqoff();
 }
 
+static __always_inline void context_guest_exit_irqoff(void) { }
+
 static __always_inline void guest_exit_irqoff(void)
 {
 	instrumentation_begin();