Messages in this thread | | | Date | Mon, 9 Jan 2023 17:19:59 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH x86/nmi 1/2] x86/nmi: Accumulate NMI-progress evidence in exc_nmi() |
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On Wed, Jan 04, 2023 at 05:15:36PM -0800, Paul E. McKenney wrote:
> diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c > index cec0bfa3bc04f..4f1651dc65b3a 100644 > --- a/arch/x86/kernel/nmi.c > +++ b/arch/x86/kernel/nmi.c > @@ -69,6 +69,15 @@ struct nmi_stats { > unsigned int unknown; > unsigned int external; > unsigned int swallow; > + unsigned long recv_jiffies; > + unsigned long idt_seq; > + unsigned long idt_nmi_seq; > + unsigned long idt_ignored; > + atomic_long_t idt_calls; > + unsigned long idt_seq_snap; > + unsigned long idt_nmi_seq_snap; > + unsigned long idt_ignored_snap; > + long idt_calls_snap; > };
Urgh, this is more than a whole cacheline of extra data :/ Can't we make this #ifdef CONFIG_NMI_CHECK_CPU ?
> @@ -509,8 +526,15 @@ DEFINE_IDTENTRY_RAW(exc_nmi) > > inc_irq_stat(__nmi_count); > > - if (!ignore_nmis) > + if (IS_ENABLED(CONFIG_NMI_CHECK_CPU) && ignore_nmis) { > + WRITE_ONCE(nsp->idt_ignored, nsp->idt_ignored + 1); > + } else if (!ignore_nmis) { > + WRITE_ONCE(nsp->idt_nmi_seq, nsp->idt_nmi_seq + 1); > + WARN_ON_ONCE(!(nsp->idt_nmi_seq & 0x1)); > default_do_nmi(regs); > + WRITE_ONCE(nsp->idt_nmi_seq, nsp->idt_nmi_seq + 1); > + WARN_ON_ONCE(nsp->idt_nmi_seq & 0x1); > + } > > irqentry_nmi_exit(regs, irq_state);
That is not a NO-OP when !CONFIG_NMI_CHECK_CPU :/
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