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         unsigned long bytes;
  21
  22         init_kstat_irqs(desc, cpu, nr);
  23
  24         if (desc->kstat_irqs != old_desc->kstat_irqs) {
  25                 /* Compute how many bytes we need per irq and allocate them */
  26                 bytes = nr * sizeof(unsigned int);
  27
  28                 memcpy(desc->kstat_irqs, old_desc->kstat_irqs, bytes);
  29         }
  30 }
  31
  32 static void free_kstat_irqs(struct irq_desc *old_desc, struct irq_desc *desc)
  33 {
  34         if (old_desc->kstat_irqs == desc->kstat_irqs)
  35                 return;
  36
  37         kfree(old_desc->kstat_irqs);
  38         old_desc->kstat_irqs = NULL;
  39 }
  40
  41 static bool init_copy_one_irq_desc(int irq, struct irq_desc *old_desc,
  42                  struct irq_desc *desc, int cpu)
  43 {
  44         memcpy(desc, old_desc, sizeof(struct irq_desc));
  45         if (!init_alloc_desc_masks(desc, cpu, false)) {
  46                 printk(KERN_ERR "irq %d: can not get new irq_desc cpumask "
  47                                 "for migration.\n", irq);
  48                 return false;
  49         }
  50         spin_lock_init(&desc->lock);
  51         desc->cpu = cpu;
  52         lockdep_set_class(&desc->lock, &irq_desc_lock_class);
  53         init_copy_kstat_irqs(old_desc, desc, cpu, nr_cpu_ids);
  54         init_copy_desc_masks(old_desc, desc);
  55         arch_init_copy_chip_data(old_desc, desc, cpu);
  56         return true;
  57 }
  58
  59 static void free_one_irq_desc(struct irq_desc *old_desc, struct irq_desc *desc)
  60 {
  61         free_kstat_irqs(old_desc, desc);
  62         arch_free_chip_data(old_desc, desc);
  63 }
  64
  65 static struct irq_desc *__real_move_irq_desc(struct irq_desc *old_desc,
  66                                                 int cpu)
  67 {
  68         struct irq_desc *desc;
  69         unsigned int irq;
  70         unsigned long flags;
  71         int node;
  72
  73         irq = old_desc->irq;
  74
  75         spin_lock_irqsave(&sparse_irq_lock, flags);
  76
  77         /* We have to check it to avoid races with another CPU */
  78         desc = irq_desc_ptrs[irq];
  79
  80         if (desc && old_desc != desc)
  81                 goto out_unlock;
  82
  83         node = cpu_to_node(cpu);
  84         desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
  85         if (!desc) {
  86                 printk(KERN_ERR "irq %d: can not get new irq_desc "
  87                                 "for migration.\n", irq);
  88                 /* still use old one */
  89                 desc = old_desc;
  90                 goto out_unlock;
  91         }
  92         if (!init_copy_one_irq_desc(irq, old_desc, desc, cpu)) {
  93                 /* still use old one */
  94                 kfree(desc);
  95                 desc = old_desc;
  96                 goto out_unlock;
  97         }
  98
  99         irq_desc_ptrs[irq] = desc;
 100         spin_unlock_irqrestore(&sparse_irq_lock, flags);
 101
 102         /* free the old one */
 103         free_one_irq_desc(old_desc, desc);
 104         spin_unlock(&old_desc->lock);
 105         kfree(old_desc);
 106         spin_lock(&desc->lock);
 107
 108         return desc;
 109
 110 out_unlock:
 111         spin_unlock_irqrestore(&sparse_irq_lock, flags);
 112
 113         return desc;
 114 }
 115
 116 struct irq_desc *move_irq_desc(struct irq_desc *desc, int cpu)
 117 {
 118         int old_cpu;
 119         int node, old_node;
 120
 121         /* those all static, do move them */
 122         if (desc->irq < NR_IRQS_LEGACY)
 123                 return desc;
 124
 125         old_cpu = desc->cpu;
 126         if (old_cpu != cpu) {
 127                 node = cpu_to_node(cpu);
 128                 old_node = cpu_to_node(old_cpu);
 129                 if (old_node != node)
 130                         desc = __real_move_irq_desc(desc, cpu);
 131                 else
 132                         desc->cpu = cpu;
 133         }
 134
 135         return desc;
 136 }
 137