kernel/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/printk.h>
   9 #include <linux/pfn.h>
  10 #include <linux/init.h>
  11
  12 #include <asm/percpu.h>
  13
  14 /* enough to cover all DEFINE_PER_CPUs in modules */
  15 #ifdef CONFIG_MODULES
  16 #define PERCPU_MODULE_RESERVE           (8 << 10)
  17 #else
  18 #define PERCPU_MODULE_RESERVE           0
  19 #endif
  20
  21 #ifndef PERCPU_ENOUGH_ROOM
  22 #define PERCPU_ENOUGH_ROOM                                              \
  23         (ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES) +      \
  24          PERCPU_MODULE_RESERVE)
  25 #endif
  26
  27 #ifdef CONFIG_PREEMPT_RT_FULL
  28
  29 #define get_local_var(var) (*({         \
  30                migrate_disable();       \
  31                this_cpu_ptr(&var);      }))
  32
  33 #define put_local_var(var) do { \
  34         (void)&(var);           \
  35         migrate_enable();       \
  36 } while (0)
  37
  38 # define get_local_ptr(var) ({          \
  39                 migrate_disable();      \
  40                 this_cpu_ptr(var);      })
  41
  42 # define put_local_ptr(var) do {        \
  43         (void)(var);                    \
  44         migrate_enable();               \
  45 } while (0)
  46
  47 #else
  48
  49 #define get_local_var(var)      get_cpu_var(var)
  50 #define put_local_var(var)      put_cpu_var(var)
  51 #define get_local_ptr(var)      get_cpu_ptr(var)
  52 #define put_local_ptr(var)      put_cpu_ptr(var)
  53
  54 #endif
  55
  56 /* minimum unit size, also is the maximum supported allocation size */
  57 #define PCPU_MIN_UNIT_SIZE              PFN_ALIGN(32 << 10)
  58
  59 /*
  60  * Percpu allocator can serve percpu allocations before slab is
  61  * initialized which allows slab to depend on the percpu allocator.
  62  * The following two parameters decide how much resource to
  63  * preallocate for this.  Keep PERCPU_DYNAMIC_RESERVE equal to or
  64  * larger than PERCPU_DYNAMIC_EARLY_SIZE.
  65  */
  66 #define PERCPU_DYNAMIC_EARLY_SLOTS      128
  67 #define PERCPU_DYNAMIC_EARLY_SIZE       (12 << 10)
  68
  69 /*
  70  * PERCPU_DYNAMIC_RESERVE indicates the amount of free area to piggy
  71  * back on the first chunk for dynamic percpu allocation if arch is
  72  * manually allocating and mapping it for faster access (as a part of
  73  * large page mapping for example).
  74  *
  75  * The following values give between one and two pages of free space
  76  * after typical minimal boot (2-way SMP, single disk and NIC) with
  77  * both defconfig and a distro config on x86_64 and 32.  More
  78  * intelligent way to determine this would be nice.
  79  */
  80 #if BITS_PER_LONG > 32
  81 #define PERCPU_DYNAMIC_RESERVE          (28 << 10)
  82 #else
  83 #define PERCPU_DYNAMIC_RESERVE          (20 << 10)
  84 #endif
  85
  86 extern void *pcpu_base_addr;
  87 extern const unsigned long *pcpu_unit_offsets;
  88
  89 struct pcpu_group_info {
  90         int                     nr_units;       /* aligned # of units */
  91         unsigned long           base_offset;    /* base address offset */
  92         unsigned int            *cpu_map;       /* unit->cpu map, empty
  93                                                  * entries contain NR_CPUS */
  94 };
  95
  96 struct pcpu_alloc_info {
  97         size_t                  static_size;
  98         size_t                  reserved_size;
  99         size_t                  dyn_size;
 100         size_t                  unit_size;
 101         size_t                  atom_size;
 102         size_t                  alloc_size;
 103         size_t                  __ai_size;      /* internal, don't use */
 104         int                     nr_groups;      /* 0 if grouping unnecessary */
 105         struct pcpu_group_info  groups[];
 106 };
 107
 108 enum pcpu_fc {
 109         PCPU_FC_AUTO,
 110         PCPU_FC_EMBED,
 111         PCPU_FC_PAGE,
 112
 113         PCPU_FC_NR,
 114 };
 115 extern const char * const pcpu_fc_names[PCPU_FC_NR];
 116
 117 extern enum pcpu_fc pcpu_chosen_fc;
 118
 119 typedef void * (*pcpu_fc_alloc_fn_t)(unsigned int cpu, size_t size,
 120                                      size_t align);
 121 typedef void (*pcpu_fc_free_fn_t)(void *ptr, size_t size);
 122 typedef void (*pcpu_fc_populate_pte_fn_t)(unsigned long addr);
 123 typedef int (pcpu_fc_cpu_distance_fn_t)(unsigned int from, unsigned int to);
 124
 125 extern struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
 126                                                              int nr_units);
 127 extern void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai);
 128
 129 extern int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
 130                                          void *base_addr);
 131
 132 #ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
 133 extern int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
 134                                 size_t atom_size,
 135                                 pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
 136                                 pcpu_fc_alloc_fn_t alloc_fn,
 137                                 pcpu_fc_free_fn_t free_fn);
 138 #endif
 139
 140 #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
 141 extern int __init pcpu_page_first_chunk(size_t reserved_size,
 142                                 pcpu_fc_alloc_fn_t alloc_fn,
 143                                 pcpu_fc_free_fn_t free_fn,
 144                                 pcpu_fc_populate_pte_fn_t populate_pte_fn);
 145 #endif
 146
 147 extern void __percpu *__alloc_reserved_percpu(size_t size, size_t align);
 148 extern bool is_kernel_percpu_address(unsigned long addr);
 149
 150 #if !defined(CONFIG_SMP) || !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
 151 extern void __init setup_per_cpu_areas(void);
 152 #endif
 153 extern void __init percpu_init_late(void);
 154
 155 extern void __percpu *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp);
 156 extern void __percpu *__alloc_percpu(size_t size, size_t align);
 157 extern void free_percpu(void __percpu *__pdata);
 158 extern phys_addr_t per_cpu_ptr_to_phys(void *addr);
 159
 160 #define alloc_percpu_gfp(type, gfp)                                     \
 161         (typeof(type) __percpu *)__alloc_percpu_gfp(sizeof(type),       \
 162                                                 __alignof__(type), gfp)
 163 #define alloc_percpu(type)                                              \
 164         (typeof(type) __percpu *)__alloc_percpu(sizeof(type),           \
 165                                                 __alignof__(type))
 166
 167 /* To avoid include hell, as printk can not declare this, we declare it here */
 168 DECLARE_PER_CPU(printk_func_t, printk_func);
 169
 170 #endif /* __LINUX_PERCPU_H */