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 <<<<<<< HEAD:mm/allocpercpu.c
  10 =======
  11 #ifndef cache_line_size
  12 #define cache_line_size()       L1_CACHE_BYTES
  13 #endif
  14
  15 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:mm/allocpercpu.c
  16 /**
  17  * percpu_depopulate - depopulate per-cpu data for given cpu
  18  * @__pdata: per-cpu data to depopulate
  19  * @cpu: depopulate per-cpu data for this cpu
  20  *
  21  * Depopulating per-cpu data for a cpu going offline would be a typical
  22  * use case. You need to register a cpu hotplug handler for that purpose.
  23  */
  24 void percpu_depopulate(void *__pdata, int cpu)
  25 {
  26         struct percpu_data *pdata = __percpu_disguise(__pdata);
  27
  28         kfree(pdata->ptrs[cpu]);
  29         pdata->ptrs[cpu] = NULL;
  30 }
  31 EXPORT_SYMBOL_GPL(percpu_depopulate);
  32
  33 /**
  34  * percpu_depopulate_mask - depopulate per-cpu data for some cpu's
  35  * @__pdata: per-cpu data to depopulate
  36  * @mask: depopulate per-cpu data for cpu's selected through mask bits
  37  */
  38 void __percpu_depopulate_mask(void *__pdata, cpumask_t *mask)
  39 {
  40         int cpu;
  41         for_each_cpu_mask(cpu, *mask)
  42                 percpu_depopulate(__pdata, cpu);
  43 }
  44 EXPORT_SYMBOL_GPL(__percpu_depopulate_mask);
  45
  46 /**
  47  * percpu_populate - populate per-cpu data for given cpu
  48  * @__pdata: per-cpu data to populate further
  49  * @size: size of per-cpu object
  50  * @gfp: may sleep or not etc.
  51  * @cpu: populate per-data for this cpu
  52  *
  53  * Populating per-cpu data for a cpu coming online would be a typical
  54  * use case. You need to register a cpu hotplug handler for that purpose.
  55  * Per-cpu object is populated with zeroed buffer.
  56  */
  57 void *percpu_populate(void *__pdata, size_t size, gfp_t gfp, int cpu)
  58 {
  59         struct percpu_data *pdata = __percpu_disguise(__pdata);
  60         int node = cpu_to_node(cpu);
  61
  62 <<<<<<< HEAD:mm/allocpercpu.c
  63 =======
  64         /*
  65          * We should make sure each CPU gets private memory.
  66          */
  67         size = roundup(size, cache_line_size());
  68
  69 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:mm/allocpercpu.c
  70         BUG_ON(pdata->ptrs[cpu]);
  71         if (node_online(node))
  72                 pdata->ptrs[cpu] = kmalloc_node(size, gfp|__GFP_ZERO, node);
  73         else
  74                 pdata->ptrs[cpu] = kzalloc(size, gfp);
  75         return pdata->ptrs[cpu];
  76 }
  77 EXPORT_SYMBOL_GPL(percpu_populate);
  78
  79 /**
  80  * percpu_populate_mask - populate per-cpu data for more cpu's
  81  * @__pdata: per-cpu data to populate further
  82  * @size: size of per-cpu object
  83  * @gfp: may sleep or not etc.
  84  * @mask: populate per-cpu data for cpu's selected through mask bits
  85  *
  86  * Per-cpu objects are populated with zeroed buffers.
  87  */
  88 int __percpu_populate_mask(void *__pdata, size_t size, gfp_t gfp,
  89                            cpumask_t *mask)
  90 {
  91         cpumask_t populated = CPU_MASK_NONE;
  92         int cpu;
  93
  94         for_each_cpu_mask(cpu, *mask)
  95                 if (unlikely(!percpu_populate(__pdata, size, gfp, cpu))) {
  96                         __percpu_depopulate_mask(__pdata, &populated);
  97                         return -ENOMEM;
  98                 } else
  99                         cpu_set(cpu, populated);
 100         return 0;
 101 }
 102 EXPORT_SYMBOL_GPL(__percpu_populate_mask);
 103
 104 /**
 105  * percpu_alloc_mask - initial setup of per-cpu data
 106  * @size: size of per-cpu object
 107  * @gfp: may sleep or not etc.
 108  * @mask: populate per-data for cpu's selected through mask bits
 109  *
 110  * Populating per-cpu data for all online cpu's would be a typical use case,
 111  * which is simplified by the percpu_alloc() wrapper.
 112  * Per-cpu objects are populated with zeroed buffers.
 113  */
 114 void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask)
 115 {
 116 <<<<<<< HEAD:mm/allocpercpu.c
 117         void *pdata = kzalloc(nr_cpu_ids * sizeof(void *), gfp);
 118 =======
 119         /*
 120          * We allocate whole cache lines to avoid false sharing
 121          */
 122         size_t sz = roundup(nr_cpu_ids * sizeof(void *), cache_line_size());
 123         void *pdata = kzalloc(sz, gfp);
 124 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:mm/allocpercpu.c
 125         void *__pdata = __percpu_disguise(pdata);
 126
 127         if (unlikely(!pdata))
 128                 return NULL;
 129         if (likely(!__percpu_populate_mask(__pdata, size, gfp, mask)))
 130                 return __pdata;
 131         kfree(pdata);
 132         return NULL;
 133 }
 134 EXPORT_SYMBOL_GPL(__percpu_alloc_mask);
 135
 136 /**
 137  * percpu_free - final cleanup of per-cpu data
 138  * @__pdata: object to clean up
 139  *
 140  * We simply clean up any per-cpu object left. No need for the client to
 141  * track and specify through a bis mask which per-cpu objects are to free.
 142  */
 143 void percpu_free(void *__pdata)
 144 {
 145         if (unlikely(!__pdata))
 146                 return;
 147         __percpu_depopulate_mask(__pdata, &cpu_possible_map);
 148         kfree(__percpu_disguise(__pdata));
 149 }
 150 EXPORT_SYMBOL_GPL(percpu_free);