include/linux/percpu.h

   1 #ifndef __LINUX_PERCPU_H
   2 #define __LINUX_PERCPU_H
   3
   4 #include <linux/mmdebug.h>
   5 #include <linux/preempt.h>
   6 #include <linux/smp.h>
   7 #include <linux/cpumask.h>
   8 #include <linux/pfn.h>
   9 #include <linux/init.h>
  10
  11 #include <asm/percpu.h>
  12
  13 /* enough to cover all DEFINE_PER_CPUs in modules */
  14 #ifdef CONFIG_MODULES
  15 #define PERCPU_MODULE_RESERVE           (8 << 10)
  16 #else
  17 #define PERCPU_MODULE_RESERVE           0
  18 #endif
  19
  20 #ifndef PERCPU_ENOUGH_ROOM
  21 #define PERCPU_ENOUGH_ROOM                                              \
  22         (ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES) +      \
  23          PERCPU_MODULE_RESERVE)
  24 #endif
  25
  26 /* minimum unit size, also is the maximum supported allocation size */
  27 #define PCPU_MIN_UNIT_SIZE              PFN_ALIGN(32 << 10)
  28
  29 /*
  30  * Percpu allocator can serve percpu allocations before slab is
  31  * initialized which allows slab to depend on the percpu allocator.
  32  * The following two parameters decide how much resource to
  33  * preallocate for this.  Keep PERCPU_DYNAMIC_RESERVE equal to or
  34  * larger than PERCPU_DYNAMIC_EARLY_SIZE.
  35  */
  36 #define PERCPU_DYNAMIC_EARLY_SLOTS      128
  37 #define PERCPU_DYNAMIC_EARLY_SIZE       (12 << 10)
  38
  39 /*
  40  * PERCPU_DYNAMIC_RESERVE indicates the amount of free area to piggy
  41  * back on the first chunk for dynamic percpu allocation if arch is
  42  * manually allocating and mapping it for faster access (as a part of
  43  * large page mapping for example).
  44  *
  45  * The following values give between one and two pages of free space
  46  * after typical minimal boot (2-way SMP, single disk and NIC) with
  47  * both defconfig and a distro config on x86_64 and 32.  More
  48  * intelligent way to determine this would be nice.
  49  */
  50 #if BITS_PER_LONG > 32
  51 #define PERCPU_DYNAMIC_RESERVE          (20 << 10)
  52 #else
  53 #define PERCPU_DYNAMIC_RESERVE          (12 << 10)
  54 #endif
  55
  56 extern void *pcpu_base_addr;
  57 extern const unsigned long *pcpu_unit_offsets;
  58
  59 struct pcpu_group_info {
  60         int                     nr_units;       /* aligned # of units */
  61         unsigned long           base_offset;    /* base address offset */
  62         unsigned int            *cpu_map;       /* unit->cpu map, empty
  63                                                  * entries contain NR_CPUS */
  64 };
  65
  66 struct pcpu_alloc_info {
  67         size_t                  static_size;
  68         size_t                  reserved_size;
  69         size_t                  dyn_size;
  70         size_t                  unit_size;
  71         size_t                  atom_size;
  72         size_t                  alloc_size;
  73         size_t                  __ai_size;      /* internal, don't use */
  74         int                     nr_groups;      /* 0 if grouping unnecessary */
  75         struct pcpu_group_info  groups[];
  76 };
  77
  78 enum pcpu_fc {
  79         PCPU_FC_AUTO,
  80         PCPU_FC_EMBED,
  81         PCPU_FC_PAGE,
  82
  83         PCPU_FC_NR,
  84 };
  85 extern const char * const pcpu_fc_names[PCPU_FC_NR];
  86
  87 extern enum pcpu_fc pcpu_chosen_fc;
  88
  89 typedef void * (*pcpu_fc_alloc_fn_t)(unsigned int cpu, size_t size,
  90                                      size_t align);
  91 typedef void (*pcpu_fc_free_fn_t)(void *ptr, size_t size);
  92 typedef void (*pcpu_fc_populate_pte_fn_t)(unsigned long addr);
  93 typedef int (pcpu_fc_cpu_distance_fn_t)(unsigned int from, unsigned int to);
  94
  95 extern struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
  96                                                              int nr_units);
  97 extern void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai);
  98
  99 extern int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
 100                                          void *base_addr);
 101
 102 #ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
 103 extern int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
 104                                 size_t atom_size,
 105                                 pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
 106                                 pcpu_fc_alloc_fn_t alloc_fn,
 107                                 pcpu_fc_free_fn_t free_fn);
 108 #endif
 109
 110 #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
 111 extern int __init pcpu_page_first_chunk(size_t reserved_size,
 112                                 pcpu_fc_alloc_fn_t alloc_fn,
 113                                 pcpu_fc_free_fn_t free_fn,
 114                                 pcpu_fc_populate_pte_fn_t populate_pte_fn);
 115 #endif
 116
 117 extern void __percpu *__alloc_reserved_percpu(size_t size, size_t align);
 118 extern bool is_kernel_percpu_address(unsigned long addr);
 119
 120 #if !defined(CONFIG_SMP) || !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
 121 extern void __init setup_per_cpu_areas(void);
 122 #endif
 123 extern void __init percpu_init_late(void);
 124
 125 extern void __percpu *__alloc_percpu(size_t size, size_t align);
 126 extern void free_percpu(void __percpu *__pdata);
 127 extern phys_addr_t per_cpu_ptr_to_phys(void *addr);
 128
 129 #define alloc_percpu(type)      \
 130         (typeof(type) __percpu *)__alloc_percpu(sizeof(type), __alignof__(type))
 131
 132 #endif /* __LINUX_PERCPU_H */