parisc: more irq statistics in /proc/interrupts

Add framework and initial values for more fine grained statistics in
/proc/interrupts.

Signed-off-by: Helge Deller <deller@gmx.de>

1 files changed, 47 insertions, 1 deletions

diff --git a/arch/parisc/kernel/irq.c b/arch/parisc/kernel/irq.c
index 810f9cf89e48..a237e32ede19 100644
--- a/arch/parisc/kernel/irq.c
+++ b/arch/parisc/kernel/irq.c
@@ -152,6 +152,40 @@ static struct irq_chip cpu_interrupt_type = {
 	.irq_retrigger	= NULL,
 };
 
+DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
+#define irq_stats(x)		(&per_cpu(irq_stat, x))
+
+/*
+ * /proc/interrupts printing for arch specific interrupts
+ */
+int arch_show_interrupts(struct seq_file *p, int prec)
+{
+	int j;
+
+#ifdef CONFIG_DEBUG_STACKOVERFLOW
+	seq_printf(p, "%*s: ", prec, "STK");
+	for_each_online_cpu(j)
+		seq_printf(p, "%10u ", irq_stats(j)->kernel_stack_usage);
+	seq_printf(p, "  Kernel stack usage\n");
+#endif
+#ifdef CONFIG_SMP
+	seq_printf(p, "%*s: ", prec, "RES");
+	for_each_online_cpu(j)
+		seq_printf(p, "%10u ", irq_stats(j)->irq_resched_count);
+	seq_printf(p, "  Rescheduling interrupts\n");
+	seq_printf(p, "%*s: ", prec, "CAL");
+	for_each_online_cpu(j)
+		seq_printf(p, "%10u ", irq_stats(j)->irq_call_count -
+					irq_stats(j)->irq_tlb_count);
+	seq_printf(p, "  Function call interrupts\n");
+	seq_printf(p, "%*s: ", prec, "TLB");
+	for_each_online_cpu(j)
+		seq_printf(p, "%10u ", irq_stats(j)->irq_tlb_count);
+	seq_printf(p, "  TLB shootdowns\n");
+#endif
+	return 0;
+}
+
 int show_interrupts(struct seq_file *p, void *v)
 {
 	int i = *(loff_t *) v, j;
@@ -219,6 +253,9 @@ int show_interrupts(struct seq_file *p, void *v)
 		raw_spin_unlock_irqrestore(&desc->lock, flags);
 	}
 
+	if (i == NR_IRQS)
+		arch_show_interrupts(p, 3);
+
 	return 0;
 }
 
@@ -340,13 +377,22 @@ static inline void stack_overflow_check(struct pt_regs *regs)
 	/* Our stack starts directly behind the thread_info struct. */
 	unsigned long stack_start = (unsigned long) current_thread_info();
 	unsigned long sp = regs->gr[30];
+	unsigned long stack_usage;
+	unsigned int *last_usage;
 
 	/* if sr7 != 0, we interrupted a userspace process which we do not want
 	 * to check for stack overflow. We will only check the kernel stack. */
 	if (regs->sr[7])
 		return;
 
-	if (likely((sp - stack_start) < (THREAD_SIZE - STACK_MARGIN)))
+	/* calculate kernel stack usage */
+	stack_usage = sp - stack_start;
+	last_usage = &per_cpu(irq_stat.kernel_stack_usage, smp_processor_id());
+
+	if (unlikely(stack_usage > *last_usage))
+		*last_usage = stack_usage;
+
+	if (likely(stack_usage < (THREAD_SIZE - STACK_MARGIN)))
 		return;
 
 	pr_emerg("stackcheck: %s will most likely overflow kernel stack "