Commit 17081102 authored by Anton Blanchard's avatar Anton Blanchard Committed by Benjamin Herrenschmidt
Browse files

powerpc: Convert global "BAD" interrupt to per cpu spurious 



I often get asked if BAD interrupts are really bad. On some boxes (eg
IBM machines running a hypervisor) there are valid cases where are
presented with an interrupt that is not for us. These cases are common
enough to show up as thousands of BAD interrupts a day.

Tone them down by calling them spurious. Since they can be a significant cause
of OS jitter, we may as well log them per cpu so we know where they are
occurring.

Signed-off-by: default avatarAnton Blanchard <anton@samba.org>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 89713ed1

arch/powerpc/include/asm/hardirq.h

+1 −3
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ typedef struct { 
	unsigned int timer_irqs;

	unsigned int pmu_irqs;

	unsigned int mce_exceptions;

	unsigned int spurious_irqs;

} ____cacheline_aligned irq_cpustat_t;



DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
@@ -25,7 +26,4 @@ static inline void ack_bad_irq(unsigned int irq) 
extern u64 arch_irq_stat_cpu(unsigned int cpu);

#define arch_irq_stat_cpu	arch_irq_stat_cpu



extern u64 arch_irq_stat(void);

#define arch_irq_stat		arch_irq_stat



#endif /* _ASM_POWERPC_HARDIRQ_H */

arch/powerpc/kernel/irq.c

+7 −12
Original line number Diff line number Diff line
@@ -77,7 +77,6 @@ DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat); 
EXPORT_PER_CPU_SYMBOL(irq_stat);



int __irq_offset_value;

static int ppc_spurious_interrupts;



#ifdef CONFIG_PPC32

EXPORT_SYMBOL(__irq_offset_value);
@@ -201,6 +200,11 @@ static int show_other_interrupts(struct seq_file *p, int prec) 
		seq_printf(p, "%10u ", per_cpu(irq_stat, j).timer_irqs);

        seq_printf(p, "  Local timer interrupts\n");



	seq_printf(p, "%*s: ", prec, "SPU");

	for_each_online_cpu(j)

		seq_printf(p, "%10u ", per_cpu(irq_stat, j).spurious_irqs);

	seq_printf(p, "  Spurious interrupts\n");



	seq_printf(p, "%*s: ", prec, "CNT");

	for_each_online_cpu(j)

		seq_printf(p, "%10u ", per_cpu(irq_stat, j).pmu_irqs);
@@ -211,8 +215,6 @@ static int show_other_interrupts(struct seq_file *p, int prec) 
		seq_printf(p, "%10u ", per_cpu(irq_stat, j).mce_exceptions);

	seq_printf(p, "  Machine check exceptions\n");



	seq_printf(p, "%*s: %10u\n", prec, "BAD", ppc_spurious_interrupts);



	return 0;

}
@@ -282,13 +284,7 @@ u64 arch_irq_stat_cpu(unsigned int cpu) 


	sum += per_cpu(irq_stat, cpu).pmu_irqs;

	sum += per_cpu(irq_stat, cpu).mce_exceptions;



	return sum;

}



u64 arch_irq_stat(void)

{

	u64 sum = ppc_spurious_interrupts;

	sum += per_cpu(irq_stat, cpu).spurious_irqs;



	return sum;

}
@@ -404,8 +400,7 @@ void do_IRQ(struct pt_regs *regs) 
	if (irq != NO_IRQ && irq != NO_IRQ_IGNORE)

		handle_one_irq(irq);

	else if (irq != NO_IRQ_IGNORE)

		/* That's not SMP safe ... but who cares ? */

		ppc_spurious_interrupts++;

		__get_cpu_var(irq_stat).spurious_irqs++;



	irq_exit();

	set_irq_regs(old_regs);

CRA Git | Maintained and supported by SUSTech CRA and CCSE