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         if (pdata->ptrs[cpu]) {
  21                 kfree(pdata->ptrs[cpu]);
  22                 pdata->ptrs[cpu] = NULL;
  23         }
  24 }
  25 EXPORT_SYMBOL_GPL(percpu_depopulate);
  26
  27 /**
  28  * percpu_depopulate_mask - depopulate per-cpu data for some cpu's
  29  * @__pdata: per-cpu data to depopulate
  30  * @mask: depopulate per-cpu data for cpu's selected through mask bits
  31  */
  32 void __percpu_depopulate_mask(void *__pdata, cpumask_t *mask)
  33 {
  34         int cpu;
  35         for_each_cpu_mask(cpu, *mask)
  36                 percpu_depopulate(__pdata, cpu);
  37 }
  38 EXPORT_SYMBOL_GPL(__percpu_depopulate_mask);
  39
  40 /**
  41  * percpu_populate - populate per-cpu data for given cpu
  42  * @__pdata: per-cpu data to populate further
  43  * @size: size of per-cpu object
  44  * @gfp: may sleep or not etc.
  45  * @cpu: populate per-data for this cpu
  46  *
  47  * Populating per-cpu data for a cpu coming online would be a typical
  48  * use case. You need to register a cpu hotplug handler for that purpose.
  49  * Per-cpu object is populated with zeroed buffer.
  50  */
  51 void *percpu_populate(void *__pdata, size_t size, gfp_t gfp, int cpu)
  52 {
  53         struct percpu_data *pdata = __percpu_disguise(__pdata);
  54         int node = cpu_to_node(cpu);
  55
  56         BUG_ON(pdata->ptrs[cpu]);
  57         if (node_online(node)) {
  58                 /* FIXME: kzalloc_node(size, gfp, node) */
  59                 pdata->ptrs[cpu] = kmalloc_node(size, gfp, node);
  60                 if (pdata->ptrs[cpu])
  61                         memset(pdata->ptrs[cpu], 0, size);
  62         } else
  63                 pdata->ptrs[cpu] = kzalloc(size, gfp);
  64         return pdata->ptrs[cpu];
  65 }
  66 EXPORT_SYMBOL_GPL(percpu_populate);
  67
  68 /**
  69  * percpu_populate_mask - populate per-cpu data for more cpu's
  70  * @__pdata: per-cpu data to populate further
  71  * @size: size of per-cpu object
  72  * @gfp: may sleep or not etc.
  73  * @mask: populate per-cpu data for cpu's selected through mask bits
  74  *
  75  * Per-cpu objects are populated with zeroed buffers.
  76  */
  77 int __percpu_populate_mask(void *__pdata, size_t size, gfp_t gfp,
  78                            cpumask_t *mask)
  79 {
  80         cpumask_t populated = CPU_MASK_NONE;
  81         int cpu;
  82
  83         for_each_cpu_mask(cpu, *mask)
  84                 if (unlikely(!percpu_populate(__pdata, size, gfp, cpu))) {
  85                         __percpu_depopulate_mask(__pdata, &populated);
  86                         return -ENOMEM;
  87                 } else
  88                         cpu_set(cpu, populated);
  89         return 0;
  90 }
  91 EXPORT_SYMBOL_GPL(__percpu_populate_mask);
  92
  93 /**
  94  * percpu_alloc_mask - initial setup of per-cpu data
  95  * @size: size of per-cpu object
  96  * @gfp: may sleep or not etc.
  97  * @mask: populate per-data for cpu's selected through mask bits
  98  *
  99  * Populating per-cpu data for all online cpu's would be a typical use case,
 100  * which is simplified by the percpu_alloc() wrapper.
 101  * Per-cpu objects are populated with zeroed buffers.
 102  */
 103 void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask)
 104 {
 105         void *pdata = kzalloc(sizeof(struct percpu_data), gfp);
 106         void *__pdata = __percpu_disguise(pdata);
 107
 108         if (unlikely(!pdata))
 109                 return NULL;
 110         if (likely(!__percpu_populate_mask(__pdata, size, gfp, mask)))
 111                 return __pdata;
 112         kfree(pdata);
 113         return NULL;
 114 }
 115 EXPORT_SYMBOL_GPL(__percpu_alloc_mask);
 116
 117 /**
 118  * percpu_free - final cleanup of per-cpu data
 119  * @__pdata: object to clean up
 120  *
 121  * We simply clean up any per-cpu object left. No need for the client to
 122  * track and specify through a bis mask which per-cpu objects are to free.
 123  */
 124 void percpu_free(void *__pdata)
 125 {
 126         __percpu_depopulate_mask(__pdata, &cpu_possible_map);
 127         kfree(__percpu_disguise(__pdata));
 128 }
 129 EXPORT_SYMBOL_GPL(percpu_free);