git.oblomov.eu Git - linux-2.6/blob - 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 void 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         spin_lock_init(&desc->lock);
  41         desc->cpu = cpu;
  42         lockdep_set_class(&desc->lock, &irq_desc_lock_class);
  43         init_copy_kstat_irqs(old_desc, desc, cpu, nr_cpu_ids);
  44         arch_init_copy_chip_data(old_desc, desc, cpu);
  45 }
  46
  47 static void free_one_irq_desc(struct irq_desc *old_desc, struct irq_desc *desc)
  48 {
  49         free_kstat_irqs(old_desc, desc);
  50         arch_free_chip_data(old_desc, desc);
  51 }
  52
  53 static struct irq_desc *__real_move_irq_desc(struct irq_desc *old_desc,
  54                                                 int cpu)
  55 {
  56         struct irq_desc *desc;
  57         unsigned int irq;
  58         unsigned long flags;
  59         int node;
  60
  61         irq = old_desc->irq;
  62
  63         spin_lock_irqsave(&sparse_irq_lock, flags);
  64
  65         /* We have to check it to avoid races with another CPU */
  66         desc = irq_desc_ptrs[irq];
  67
  68         if (desc && old_desc != desc)
  69                 goto out_unlock;
  70
  71         node = cpu_to_node(cpu);
  72         desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
  73         if (!desc) {
  74                 printk(KERN_ERR "irq %d: can not get new irq_desc for migration.\n", irq);
  75                 /* still use old one */
  76                 desc = old_desc;
  77                 goto out_unlock;
  78         }
  79         init_copy_one_irq_desc(irq, old_desc, desc, cpu);
  80
  81         irq_desc_ptrs[irq] = desc;
  82         spin_unlock_irqrestore(&sparse_irq_lock, flags);
  83
  84         /* free the old one */
  85         free_one_irq_desc(old_desc, desc);
  86         spin_unlock(&old_desc->lock);
  87         kfree(old_desc);
  88         spin_lock(&desc->lock);
  89
  90         return desc;
  91
  92 out_unlock:
  93         spin_unlock_irqrestore(&sparse_irq_lock, flags);
  94
  95         return desc;
  96 }
  97
  98 struct irq_desc *move_irq_desc(struct irq_desc *desc, int cpu)
  99 {
 100         int old_cpu;
 101         int node, old_node;
 102
 103         /* those all static, do move them */
 104         if (desc->irq < NR_IRQS_LEGACY)
 105                 return desc;
 106
 107         old_cpu = desc->cpu;
 108         if (old_cpu != cpu) {
 109                 node = cpu_to_node(cpu);
 110                 old_node = cpu_to_node(old_cpu);
 111                 if (old_node != node)
 112                         desc = __real_move_irq_desc(desc, cpu);
 113                 else
 114                         desc->cpu = cpu;
 115         }
 116
 117         return desc;
 118 }
 119