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         free_desc_masks(old_desc, desc);
  58         arch_free_chip_data(old_desc, desc);
  59 }
  60
  61 static struct irq_desc *__real_move_irq_desc(struct irq_desc *old_desc,
  62                                                 int cpu)
  63 {
  64         struct irq_desc *desc;
  65         unsigned int irq;
  66         unsigned long flags;
  67         int node;
  68
  69         irq = old_desc->irq;
  70
  71         spin_lock_irqsave(&sparse_irq_lock, flags);
  72
  73         /* We have to check it to avoid races with another CPU */
  74         desc = irq_desc_ptrs[irq];
  75
  76         if (desc && old_desc != desc)
  77                 goto out_unlock;
  78
  79         node = cpu_to_node(cpu);
  80         desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
  81         if (!desc) {
  82                 printk(KERN_ERR "irq %d: can not get new irq_desc "
  83                                 "for migration.\n", irq);
  84                 /* still use old one */
  85                 desc = old_desc;
  86                 goto out_unlock;
  87         }
  88         if (!init_copy_one_irq_desc(irq, old_desc, desc, cpu)) {
  89                 /* still use old one */
  90                 kfree(desc);
  91                 desc = old_desc;
  92                 goto out_unlock;
  93         }
  94
  95         irq_desc_ptrs[irq] = desc;
  96         spin_unlock_irqrestore(&sparse_irq_lock, flags);
  97
  98         /* free the old one */
  99         free_one_irq_desc(old_desc, desc);
 100         spin_unlock(&old_desc->lock);
 101         kfree(old_desc);
 102         spin_lock(&desc->lock);
 103
 104         return desc;
 105
 106 out_unlock:
 107         spin_unlock_irqrestore(&sparse_irq_lock, flags);
 108
 109         return desc;
 110 }
 111
 112 struct irq_desc *move_irq_desc(struct irq_desc *desc, int cpu)
 113 {
 114         int old_cpu;
 115         int node, old_node;
 116
 117         /* those all static, do move them */
 118         if (desc->irq < NR_IRQS_LEGACY)
 119                 return desc;
 120
 121         old_cpu = desc->cpu;
 122         if (old_cpu != cpu) {
 123                 node = cpu_to_node(cpu);
 124                 old_node = cpu_to_node(old_cpu);
 125                 if (old_node != node)
 126                         desc = __real_move_irq_desc(desc, cpu);
 127                 else
 128                         desc->cpu = cpu;
 129         }
 130
 131         return desc;
 132 }
 133