lib/pcounter.c

   1 /*
   2  * Define default pcounter functions
   3  * Note that often used pcounters use dedicated functions to get a speed increase.
   4  * (see DEFINE_PCOUNTER/REF_PCOUNTER_MEMBER)
   5  */
   6
   7 #include <linux/module.h>
   8 #include <linux/pcounter.h>
   9 #include <linux/smp.h>
  10 #include <linux/cpumask.h>
  11
  12 static void pcounter_dyn_add(struct pcounter *self, int inc)
  13 {
  14         per_cpu_ptr(self->per_cpu_values, smp_processor_id())[0] += inc;
  15 }
  16
  17 static int pcounter_dyn_getval(const struct pcounter *self, int cpu)
  18 {
  19         return per_cpu_ptr(self->per_cpu_values, cpu)[0];
  20 }
  21
  22 int pcounter_getval(const struct pcounter *self)
  23 {
  24         int res = 0, cpu;
  25
  26         for_each_possible_cpu(cpu)
  27                 res += self->getval(self, cpu);
  28
  29         return res;
  30 }
  31 EXPORT_SYMBOL_GPL(pcounter_getval);
  32
  33 int pcounter_alloc(struct pcounter *self)
  34 {
  35         int rc = 0;
  36         if (self->add == NULL) {
  37                 self->per_cpu_values = alloc_percpu(int);
  38                 if (self->per_cpu_values != NULL) {
  39                         self->add    = pcounter_dyn_add;
  40                         self->getval = pcounter_dyn_getval;
  41                 } else
  42                         rc = 1;
  43         }
  44         return rc;
  45 }
  46 EXPORT_SYMBOL_GPL(pcounter_alloc);
  47
  48 void pcounter_free(struct pcounter *self)
  49 {
  50         if (self->per_cpu_values != NULL) {
  51                 free_percpu(self->per_cpu_values);
  52                 self->per_cpu_values = NULL;
  53                 self->getval = NULL;
  54                 self->add = NULL;
  55         }
  56 }
  57 EXPORT_SYMBOL_GPL(pcounter_free);
  58