kernel/irq/numa_migrate.c

   1 /*
   2  * NUMA irq-desc migration code
   3  *
   4  * Migrate IRQ data structures (irq_desc, chip_data, etc.) over to
   5  * the new "home node" of the IRQ.
   6  */
   7
   8 #include <linux/irq.h>
   9 #include <linux/module.h>
  10 #include <linux/random.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/kernel_stat.h>
  13
  14 #include "internals.h"
  15
  16 static void init_copy_kstat_irqs(struct irq_desc *old_desc,
  17                                  struct irq_desc *desc,
  18                                  int cpu, int nr)
  19 {
  20         init_kstat_irqs(desc, cpu, nr);
  21
  22         if (desc->kstat_irqs != old_desc->kstat_irqs)
  23                 memcpy(desc->kstat_irqs, old_desc->kstat_irqs,
  24                          nr * sizeof(*desc->kstat_irqs));
  25 }
  26
  27 static void free_kstat_irqs(struct irq_desc *old_desc, struct irq_desc *desc)
  28 {
  29         if (old_desc->kstat_irqs == desc->kstat_irqs)
  30                 return;
  31
  32         kfree(old_desc->kstat_irqs);
  33         old_desc->kstat_irqs = NULL;
  34 }
  35
  36 static bool init_copy_one_irq_desc(int irq, struct irq_desc *old_desc,
  37                  struct irq_desc *desc, int cpu)
  38 {
  39         memcpy(desc, old_desc, sizeof(struct irq_desc));
  40         if (!init_alloc_desc_masks(desc, cpu, false)) {
  41                 printk(KERN_ERR "irq %d: can not get new irq_desc cpumask "
  42                                 "for migration.\n", irq);
  43                 return false;
  44         }
  45         spin_lock_init(&desc->lock);
  46         desc->cpu = cpu;
  47         lockdep_set_class(&desc->lock, &irq_desc_lock_class);
  48         init_copy_kstat_irqs(old_desc, desc, cpu, nr_cpu_ids);
  49         init_copy_desc_masks(old_desc, desc);
  50         arch_init_copy_chip_data(old_desc, desc, cpu);
  51         return true;
  52 }
  53
  54 static void free_one_irq_desc(struct irq_desc *old_desc, struct irq_desc *desc)
  55 {
  56         free_kstat_irqs(old_desc, desc);
  57         arch_free_chip_data(old_desc, desc);
  58 }
  59
  60 static struct irq_desc *__real_move_irq_desc(struct irq_desc *old_desc,
  61                                                 int cpu)
  62 {
  63         struct irq_desc *desc;
  64         unsigned int irq;
  65         unsigned long flags;
  66         int node;
  67
  68         irq = old_desc->irq;
  69
  70         spin_lock_irqsave(&sparse_irq_lock, flags);
  71
  72         /* We have to check it to avoid races with another CPU */
  73         desc = irq_desc_ptrs[irq];
  74
  75         if (desc && old_desc != desc)
  76                 goto out_unlock;
  77
  78         node = cpu_to_node(cpu);
  79         desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
  80         if (!desc) {
  81                 printk(KERN_ERR "irq %d: can not get new irq_desc "
  82                                 "for migration.\n", irq);
  83                 /* still use old one */
  84                 desc = old_desc;
  85                 goto out_unlock;
  86         }
  87         if (!init_copy_one_irq_desc(irq, old_desc, desc, cpu)) {
  88                 /* still use old one */
  89                 kfree(desc);
  90                 desc = old_desc;
  91                 goto out_unlock;
  92         }
  93
  94         irq_desc_ptrs[irq] = desc;
  95         spin_unlock_irqrestore(&sparse_irq_lock, flags);
  96
  97         /* free the old one */
  98         free_one_irq_desc(old_desc, desc);
  99         spin_unlock(&old_desc->lock);
 100         kfree(old_desc);
 101         spin_lock(&desc->lock);
 102
 103         return desc;
 104
 105 out_unlock:
 106         spin_unlock_irqrestore(&sparse_irq_lock, flags);
 107
 108         return desc;
 109 }
 110
 111 struct irq_desc *move_irq_desc(struct irq_desc *desc, int cpu)
 112 {
 113         int old_cpu;
 114         int node, old_node;
 115
 116         /* those all static, do move them */
 117         if (desc->irq < NR_IRQS_LEGACY)
 118                 return desc;
 119
 120         old_cpu = desc->cpu;
 121         if (old_cpu != cpu) {
 122                 node = cpu_to_node(cpu);
 123                 old_node = cpu_to_node(old_cpu);
 124                 if (old_node != node)
 125                         desc = __real_move_irq_desc(desc, cpu);
 126                 else
 127                         desc->cpu = cpu;
 128         }
 129
 130         return desc;
 131 }
 132