mm/allocpercpu.c

   1 /*
   2  * linux/mm/allocpercpu.c
   3  *
   4  * Separated from slab.c August 11, 2006 Christoph Lameter <clameter@sgi.com>
   5  */
   6 #include <linux/mm.h>
   7 #include <linux/module.h>
   8
   9 /**
  10  * percpu_depopulate - depopulate per-cpu data for given cpu
  11  * @__pdata: per-cpu data to depopulate
  12  * @cpu: depopulate per-cpu data for this cpu
  13  *
  14  * Depopulating per-cpu data for a cpu going offline would be a typical
  15  * use case. You need to register a cpu hotplug handler for that purpose.
  16  */
  17 void percpu_depopulate(void *__pdata, int cpu)
  18 {
  19         struct percpu_data *pdata = __percpu_disguise(__pdata);
  20
  21         kfree(pdata->ptrs[cpu]);
  22         pdata->ptrs[cpu] = NULL;
  23 }
  24 EXPORT_SYMBOL_GPL(percpu_depopulate);
  25
  26 /**
  27  * percpu_depopulate_mask - depopulate per-cpu data for some cpu's
  28  * @__pdata: per-cpu data to depopulate
  29  * @mask: depopulate per-cpu data for cpu's selected through mask bits
  30  */
  31 void __percpu_depopulate_mask(void *__pdata, cpumask_t *mask)
  32 {
  33         int cpu;
  34         for_each_cpu_mask(cpu, *mask)
  35                 percpu_depopulate(__pdata, cpu);
  36 }
  37 EXPORT_SYMBOL_GPL(__percpu_depopulate_mask);
  38
  39 /**
  40  * percpu_populate - populate per-cpu data for given cpu
  41  * @__pdata: per-cpu data to populate further
  42  * @size: size of per-cpu object
  43  * @gfp: may sleep or not etc.
  44  * @cpu: populate per-data for this cpu
  45  *
  46  * Populating per-cpu data for a cpu coming online would be a typical
  47  * use case. You need to register a cpu hotplug handler for that purpose.
  48  * Per-cpu object is populated with zeroed buffer.
  49  */
  50 void *percpu_populate(void *__pdata, size_t size, gfp_t gfp, int cpu)
  51 {
  52         struct percpu_data *pdata = __percpu_disguise(__pdata);
  53         int node = cpu_to_node(cpu);
  54
  55         BUG_ON(pdata->ptrs[cpu]);
  56         if (node_online(node))
  57                 pdata->ptrs[cpu] = kmalloc_node(size, gfp|__GFP_ZERO, node);
  58         else
  59                 pdata->ptrs[cpu] = kzalloc(size, gfp);
  60         return pdata->ptrs[cpu];
  61 }
  62 EXPORT_SYMBOL_GPL(percpu_populate);
  63
  64 /**
  65  * percpu_populate_mask - populate per-cpu data for more cpu's
  66  * @__pdata: per-cpu data to populate further
  67  * @size: size of per-cpu object
  68  * @gfp: may sleep or not etc.
  69  * @mask: populate per-cpu data for cpu's selected through mask bits
  70  *
  71  * Per-cpu objects are populated with zeroed buffers.
  72  */
  73 int __percpu_populate_mask(void *__pdata, size_t size, gfp_t gfp,
  74                            cpumask_t *mask)
  75 {
  76         cpumask_t populated = CPU_MASK_NONE;
  77         int cpu;
  78
  79         for_each_cpu_mask(cpu, *mask)
  80                 if (unlikely(!percpu_populate(__pdata, size, gfp, cpu))) {
  81                         __percpu_depopulate_mask(__pdata, &populated);
  82                         return -ENOMEM;
  83                 } else
  84                         cpu_set(cpu, populated);
  85         return 0;
  86 }
  87 EXPORT_SYMBOL_GPL(__percpu_populate_mask);
  88
  89 /**
  90  * percpu_alloc_mask - initial setup of per-cpu data
  91  * @size: size of per-cpu object
  92  * @gfp: may sleep or not etc.
  93  * @mask: populate per-data for cpu's selected through mask bits
  94  *
  95  * Populating per-cpu data for all online cpu's would be a typical use case,
  96  * which is simplified by the percpu_alloc() wrapper.
  97  * Per-cpu objects are populated with zeroed buffers.
  98  */
  99 void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask)
 100 {
 101         void *pdata = kzalloc(nr_cpu_ids * sizeof(void *), gfp);
 102         void *__pdata = __percpu_disguise(pdata);
 103
 104         if (unlikely(!pdata))
 105                 return NULL;
 106         if (likely(!__percpu_populate_mask(__pdata, size, gfp, mask)))
 107                 return __pdata;
 108         kfree(pdata);
 109         return NULL;
 110 }
 111 EXPORT_SYMBOL_GPL(__percpu_alloc_mask);
 112
 113 /**
 114  * percpu_free - final cleanup of per-cpu data
 115  * @__pdata: object to clean up
 116  *
 117  * We simply clean up any per-cpu object left. No need for the client to
 118  * track and specify through a bis mask which per-cpu objects are to free.
 119  */
 120 void percpu_free(void *__pdata)
 121 {
 122         if (unlikely(!__pdata))
 123                 return;
 124         __percpu_depopulate_mask(__pdata, &cpu_possible_map);
 125         kfree(__percpu_disguise(__pdata));
 126 }
 127 EXPORT_SYMBOL_GPL(percpu_free);