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 void 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         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         arch_init_copy_chip_data(old_desc, desc, cpu);
  50 }
  51
  52 static void free_one_irq_desc(struct irq_desc *old_desc, struct irq_desc *desc)
  53 {
  54         free_kstat_irqs(old_desc, desc);
  55         arch_free_chip_data(old_desc, desc);
  56 }
  57
  58 static struct irq_desc *__real_move_irq_desc(struct irq_desc *old_desc,
  59                                                 int cpu)
  60 {
  61         struct irq_desc *desc;
  62         unsigned int irq;
  63         unsigned long flags;
  64         int node;
  65
  66         irq = old_desc->irq;
  67
  68         spin_lock_irqsave(&sparse_irq_lock, flags);
  69
  70         /* We have to check it to avoid races with another CPU */
  71         desc = irq_desc_ptrs[irq];
  72
  73         if (desc && old_desc != desc)
  74                 goto out_unlock;
  75
  76         node = cpu_to_node(cpu);
  77         desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
  78         if (!desc) {
  79                 printk(KERN_ERR "irq %d: can not get new irq_desc for migration.\n", irq);
  80                 /* still use old one */
  81                 desc = old_desc;
  82                 goto out_unlock;
  83         }
  84         init_copy_one_irq_desc(irq, old_desc, desc, cpu);
  85
  86         irq_desc_ptrs[irq] = desc;
  87         spin_unlock_irqrestore(&sparse_irq_lock, flags);
  88
  89         /* free the old one */
  90         free_one_irq_desc(old_desc, desc);
  91         spin_unlock(&old_desc->lock);
  92         kfree(old_desc);
  93         spin_lock(&desc->lock);
  94
  95         return desc;
  96
  97 out_unlock:
  98         spin_unlock_irqrestore(&sparse_irq_lock, flags);
  99
 100         return desc;
 101 }
 102
 103 struct irq_desc *move_irq_desc(struct irq_desc *desc, int cpu)
 104 {
 105         int old_cpu;
 106         int node, old_node;
 107
 108         /* those all static, do move them */
 109         if (desc->irq < NR_IRQS_LEGACY)
 110                 return desc;
 111
 112         old_cpu = desc->cpu;
 113         if (old_cpu != cpu) {
 114                 node = cpu_to_node(cpu);
 115                 old_node = cpu_to_node(old_cpu);
 116                 if (old_node != node)
 117                         desc = __real_move_irq_desc(desc, cpu);
 118                 else
 119                         desc->cpu = cpu;
 120         }
 121
 122         return desc;
 123 }
 124