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Date:   Wed,  5 Aug 2020 17:14:30 -0700
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Subject: [RFC PATCH 6/7] core/metricfs: expose x86-specific irq information
 through metricfs
From:   Jonathan Adams <jwadams@google.com>
To:     linux-kernel@vger.kernel.org
Cc:     kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
        Jim Mattson <jmattson@google.com>,
        David Rientjes <rientjes@google.com>,
        Jonathan Adams <jwadams@google.com>
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Add metricfs support for displaying percpu irq counters for x86.
The top directory is /sys/kernel/debug/metricfs/irq_x86.
Then there is a subdirectory for each x86-specific irq counter.
For example:

    cat /sys/kernel/debug/metricfs/irq_x86/TLB/values

Signed-off-by: Jonathan Adams <jwadams@google.com>

---

jwadams@google.com: rebased to 5.8-pre6
	This is work originally done by another engineer at
	google, who would rather not have their name associated with
	this patchset. They're okay with me sending it under my name.
---
 arch/x86/kernel/irq.c | 80 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)

diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 181060247e3c..ffacbbc4066c 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -12,6 +12,7 @@
 #include <linux/delay.h>
 #include <linux/export.h>
 #include <linux/irq.h>
+#include <linux/metricfs.h>
 
 #include <asm/irq_stack.h>
 #include <asm/apic.h>
@@ -374,3 +375,82 @@ void fixup_irqs(void)
 	}
 }
 #endif
+
+#ifdef CONFIG_METRICFS
+#define METRICFS_ITEM(name, field, desc) \
+static void \
+metricfs_##name(struct metric_emitter *e, int cpu) \
+{ \
+	int64_t v = irq_stats(cpu)->field; \
+	METRIC_EMIT_PERCPU_INT(e, cpu, v); \
+} \
+METRIC_EXPORT_PERCPU_COUNTER(name, desc, metricfs_##name)
+
+METRICFS_ITEM(NMI, __nmi_count, "Non-maskable interrupts");
+#ifdef CONFIG_X86_LOCAL_APIC
+METRICFS_ITEM(LOC, apic_timer_irqs, "Local timer interrupts");
+METRICFS_ITEM(SPU, irq_spurious_count, "Spurious interrupts");
+METRICFS_ITEM(PMI, apic_perf_irqs, "Performance monitoring interrupts");
+METRICFS_ITEM(IWI, apic_irq_work_irqs, "IRQ work interrupts");
+METRICFS_ITEM(RTR, icr_read_retry_count, "APIC ICR read retries");
+#endif
+METRICFS_ITEM(PLT, x86_platform_ipis, "Platform interrupts");
+#ifdef CONFIG_SMP
+METRICFS_ITEM(RES, irq_resched_count, "Rescheduling interrupts");
+METRICFS_ITEM(CAL, irq_call_count, "Function call interrupts");
+METRICFS_ITEM(TLB, irq_tlb_count, "TLB shootdowns");
+#endif
+#ifdef CONFIG_X86_THERMAL_VECTOR
+METRICFS_ITEM(TRM, irq_thermal_count, "Thermal event interrupts");
+#endif
+#ifdef CONFIG_X86_MCE_THRESHOLD
+METRICFS_ITEM(THR, irq_threshold_count, "Threshold APIC interrupts");
+#endif
+#ifdef CONFIG_X86_MCE_AMD
+METRICFS_ITEM(DFR, irq_deferred_error_count, "Deferred Error APIC interrupts");
+#endif
+#ifdef CONFIG_HAVE_KVM
+METRICFS_ITEM(PIN, kvm_posted_intr_ipis, "Posted-interrupt notification event");
+METRICFS_ITEM(PIW, kvm_posted_intr_wakeup_ipis,
+	"Posted-interrupt wakeup event");
+#endif
+
+static int __init init_irq_metricfs(void)
+{
+	struct metricfs_subsys *subsys;
+
+	subsys = metricfs_create_subsys("irq_x86", NULL);
+
+	metric_init_NMI(subsys);
+#ifdef CONFIG_X86_LOCAL_APIC
+	metric_init_LOC(subsys);
+	metric_init_SPU(subsys);
+	metric_init_PMI(subsys);
+	metric_init_IWI(subsys);
+	metric_init_RTR(subsys);
+#endif
+	metric_init_PLT(subsys);
+#ifdef CONFIG_SMP
+	metric_init_RES(subsys);
+	metric_init_CAL(subsys);
+	metric_init_TLB(subsys);
+#endif
+#ifdef CONFIG_X86_THERMAL_VECTOR
+	metric_init_TRM(subsys);
+#endif
+#ifdef CONFIG_X86_MCE_THRESHOLD
+	metric_init_THR(subsys);
+#endif
+#ifdef CONFIG_X86_MCE_AMD
+	metric_init_DFR(subsys);
+#endif
+#ifdef CONFIG_HAVE_KVM
+	metric_init_PIN(subsys);
+	metric_init_PIW(subsys);
+#endif
+
+	return 0;
+}
+module_init(init_irq_metricfs);
+
+#endif
-- 
2.28.0.236.gb10cc79966-goog