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perf_counter/x86: Always use NMI for performance-monitoring interrupt

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Always use NMI for performance-monitoring interrupt as there could be
racy situations if we switch between irq and nmi mode frequently.

Signed-off-by: Yong Wang <yong.y.wang@intel.com>
LKML-Reference: <20090529052835.GA13657@ywang-moblin2.bj.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Yong Wang
2009-05-29 13:28:35 +08:00
committed by Ingo Molnar
parent da417a7537
commit c323d95fa4
3 changed files with 8 additions and 17 deletions
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19
arch/x86/kernel/cpu/perf_counter.c
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@ -604,7 +604,7 @@ try_generic:
hwc->counter_base = x86_pmu.perfctr;
}
perf_counters_lapic_init(hwc->nmi);
perf_counters_lapic_init();
x86_pmu.disable(hwc, idx);
@ -863,24 +863,15 @@ void set_perf_counter_pending(void)
apic->send_IPI_self(LOCAL_PENDING_VECTOR);
}
void perf_counters_lapic_init(int nmi)
void perf_counters_lapic_init(void)
{
u32 apic_val;
if (!x86_pmu_initialized())
return;
/*
* Enable the performance counter vector in the APIC LVT:
* Always use NMI for PMU
*/
apic_val = apic_read(APIC_LVTERR);
apic_write(APIC_LVTERR, apic_val | APIC_LVT_MASKED);
if (nmi)
apic_write(APIC_LVTPC, APIC_DM_NMI);
else
apic_write(APIC_LVTPC, LOCAL_PERF_VECTOR);
apic_write(APIC_LVTERR, apic_val);
apic_write(APIC_LVTPC, APIC_DM_NMI);
}
static int __kprobes
@ -1054,7 +1045,7 @@ void __init init_hw_perf_counters(void)
pr_info("... counter mask: %016Lx\n", perf_counter_mask);
perf_counters_lapic_init(0);
perf_counters_lapic_init();
register_die_notifier(&perf_counter_nmi_notifier);
}