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KVM: x86: Eliminate log spam from limited APIC timer periods

Message ID 20240724190640.2449291-1-jmattson@google.com (mailing list archive)
State New, archived
Headers show
Series KVM: x86: Eliminate log spam from limited APIC timer periods | expand

Commit Message

Jim Mattson July 24, 2024, 7:05 p.m. UTC
SAP's vSMP MemoryONE continuously requests a local APIC timer period
less than 500 us, resulting in the following kernel log spam:

  kvm: vcpu 15: requested 70240 ns lapic timer period limited to 500000 ns
  kvm: vcpu 19: requested 52848 ns lapic timer period limited to 500000 ns
  kvm: vcpu 15: requested 70256 ns lapic timer period limited to 500000 ns
  kvm: vcpu 9: requested 70256 ns lapic timer period limited to 500000 ns
  kvm: vcpu 9: requested 70208 ns lapic timer period limited to 500000 ns
  kvm: vcpu 9: requested 387520 ns lapic timer period limited to 500000 ns
  kvm: vcpu 9: requested 70160 ns lapic timer period limited to 500000 ns
  kvm: vcpu 66: requested 205744 ns lapic timer period limited to 500000 ns
  kvm: vcpu 9: requested 70224 ns lapic timer period limited to 500000 ns
  kvm: vcpu 9: requested 70256 ns lapic timer period limited to 500000 ns
  limit_periodic_timer_frequency: 7569 callbacks suppressed
  ...

To eliminate this spam, change the pr_info_ratelimited() in
limit_periodic_timer_frequency() to pr_info_once().

Reported-by: James Houghton <jthoughton@google.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
---
 arch/x86/kvm/lapic.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Paolo Bonzini July 26, 2024, 5:34 p.m. UTC | #1
On 7/24/24 21:05, Jim Mattson wrote:
> SAP's vSMP MemoryONE continuously requests a local APIC timer period
> less than 500 us, resulting in the following kernel log spam:
> 
>    kvm: vcpu 15: requested 70240 ns lapic timer period limited to 500000 ns
>    kvm: vcpu 19: requested 52848 ns lapic timer period limited to 500000 ns
>    kvm: vcpu 15: requested 70256 ns lapic timer period limited to 500000 ns
>    kvm: vcpu 9: requested 70256 ns lapic timer period limited to 500000 ns
>    kvm: vcpu 9: requested 70208 ns lapic timer period limited to 500000 ns
>    kvm: vcpu 9: requested 387520 ns lapic timer period limited to 500000 ns
>    kvm: vcpu 9: requested 70160 ns lapic timer period limited to 500000 ns
>    kvm: vcpu 66: requested 205744 ns lapic timer period limited to 500000 ns
>    kvm: vcpu 9: requested 70224 ns lapic timer period limited to 500000 ns
>    kvm: vcpu 9: requested 70256 ns lapic timer period limited to 500000 ns
>    limit_periodic_timer_frequency: 7569 callbacks suppressed
>    ...
> 
> To eliminate this spam, change the pr_info_ratelimited() in
> limit_periodic_timer_frequency() to pr_info_once().
> 
> Reported-by: James Houghton <jthoughton@google.com>
> Signed-off-by: Jim Mattson <jmattson@google.com>

Applied, thanks.

Paolo

> ---
>   arch/x86/kvm/lapic.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index f64a5cc0ce72..c576a53733e5 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -1743,7 +1743,7 @@ static void limit_periodic_timer_frequency(struct kvm_lapic *apic)
>   		s64 min_period = min_timer_period_us * 1000LL;
>   
>   		if (apic->lapic_timer.period < min_period) {
> -			pr_info_ratelimited(
> +			pr_info_once(
>   			    "vcpu %i: requested %lld ns "
>   			    "lapic timer period limited to %lld ns\n",
>   			    apic->vcpu->vcpu_id,
diff mbox series

Patch

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index f64a5cc0ce72..c576a53733e5 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1743,7 +1743,7 @@  static void limit_periodic_timer_frequency(struct kvm_lapic *apic)
 		s64 min_period = min_timer_period_us * 1000LL;
 
 		if (apic->lapic_timer.period < min_period) {
-			pr_info_ratelimited(
+			pr_info_once(
 			    "vcpu %i: requested %lld ns "
 			    "lapic timer period limited to %lld ns\n",
 			    apic->vcpu->vcpu_id,