x86: smarten /proc/interrupts output

Impact: change /proc/interrupts output ABI

With the number of interrupts on large systems growing, assumptions on
the width an interrupt number requires when converted to a decimal
string turn invalid. Therefore, calculate the maximum number of digits
dynamically.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
LKML-Reference: <49B911EB.76E4.0078.0@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 18 insertions, 15 deletions

diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index b864341dcc45..b8ac3b6cf776 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -45,16 +45,16 @@ void ack_bad_irq(unsigned int irq)
 /*
  * /proc/interrupts printing:
  */
-static int show_other_interrupts(struct seq_file *p)
+static int show_other_interrupts(struct seq_file *p, int prec)
 {
         int j;
 
-        seq_printf(p, "NMI: ");
+        seq_printf(p, "%*s: ", prec, "NMI");
         for_each_online_cpu(j)
                 seq_printf(p, "%10u ", irq_stats(j)->__nmi_count);
         seq_printf(p, "  Non-maskable interrupts\n");
 #ifdef CONFIG_X86_LOCAL_APIC
-        seq_printf(p, "LOC: ");
+        seq_printf(p, "%*s: ", prec, "LOC");
         for_each_online_cpu(j)
                 seq_printf(p, "%10u ", irq_stats(j)->apic_timer_irqs);
         seq_printf(p, "  Local timer interrupts\n");
@@ -66,40 +66,40 @@ static int show_other_interrupts(struct seq_file *p)
                 seq_printf(p, "  Platform interrupts\n");
         }
 #ifdef CONFIG_SMP
-        seq_printf(p, "RES: ");
+        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, "CAL: ");
+        seq_printf(p, "%*s: ", prec, "CAL");
         for_each_online_cpu(j)
                 seq_printf(p, "%10u ", irq_stats(j)->irq_call_count);
         seq_printf(p, "  Function call interrupts\n");
-        seq_printf(p, "TLB: ");
+        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
 #ifdef CONFIG_X86_MCE
-        seq_printf(p, "TRM: ");
+        seq_printf(p, "%*s: ", prec, "TRM");
         for_each_online_cpu(j)
                 seq_printf(p, "%10u ", irq_stats(j)->irq_thermal_count);
         seq_printf(p, "  Thermal event interrupts\n");
 # ifdef CONFIG_X86_64
-        seq_printf(p, "THR: ");
+        seq_printf(p, "%*s: ", prec, "THR");
         for_each_online_cpu(j)
                 seq_printf(p, "%10u ", irq_stats(j)->irq_threshold_count);
         seq_printf(p, "  Threshold APIC interrupts\n");
 # endif
 #endif
 #ifdef CONFIG_X86_LOCAL_APIC
-        seq_printf(p, "SPU: ");
+        seq_printf(p, "%*s: ", prec, "SPU");
         for_each_online_cpu(j)
                 seq_printf(p, "%10u ", irq_stats(j)->irq_spurious_count);
         seq_printf(p, "  Spurious interrupts\n");
 #endif
-        seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
+        seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
 #if defined(CONFIG_X86_IO_APIC)
-        seq_printf(p, "MIS: %10u\n", atomic_read(&irq_mis_count));
+        seq_printf(p, "%*s: %10u\n", prec, "MIS", atomic_read(&irq_mis_count));
 #endif
         return 0;
 }
@@ -107,19 +107,22 @@ static int show_other_interrupts(struct seq_file *p)
 int show_interrupts(struct seq_file *p, void *v)
 {
         unsigned long flags, any_count = 0;
-        int i = *(loff_t *) v, j;
+        int i = *(loff_t *) v, j, prec;
         struct irqaction *action;
         struct irq_desc *desc;
 
         if (i > nr_irqs)
                 return 0;
 
+        for (prec = 3, j = 1000; prec < 10 && j <= nr_irqs; ++prec)
+                j *= 10;
+
         if (i == nr_irqs)
-                return show_other_interrupts(p);
+                return show_other_interrupts(p, prec);
 
         /* print header */
         if (i == 0) {
-                seq_printf(p, "           ");
+                seq_printf(p, "%*s", prec + 8, "");
                 for_each_online_cpu(j)
                         seq_printf(p, "CPU%-8d", j);
                 seq_putc(p, '\n');
@@ -140,7 +143,7 @@ int show_interrupts(struct seq_file *p, void *v)
         if (!action && !any_count)
                 goto out;
 
-        seq_printf(p, "%3d: ", i);
+        seq_printf(p, "%*d: ", prec, i);
 #ifndef CONFIG_SMP
         seq_printf(p, "%10u ", kstat_irqs(i));
 #else