include/linux/percpu.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __LINUX_PERCPU_H
   3 #define __LINUX_PERCPU_H
   4
   5 #include <linux/alloc_tag.h>
   6 #include <linux/mmdebug.h>
   7 #include <linux/preempt.h>
   8 #include <linux/smp.h>
   9 #include <linux/pfn.h>
  10 #include <linux/init.h>
  11 #include <linux/cleanup.h>
  12 #include <linux/sched.h>
  13
  14 #include <asm/percpu.h>
  15
  16 /* enough to cover all DEFINE_PER_CPUs in modules */
  17 #ifdef CONFIG_MODULES
  18 #define PERCPU_MODULE_RESERVE           (8 << 10)
  19 #else
  20 #define PERCPU_MODULE_RESERVE           0
  21 #endif
  22
  23 /* minimum unit size, also is the maximum supported allocation size */
  24 #define PCPU_MIN_UNIT_SIZE              PFN_ALIGN(32 << 10)
  25
  26 /* minimum allocation size and shift in bytes */
  27 #define PCPU_MIN_ALLOC_SHIFT            2
  28 #define PCPU_MIN_ALLOC_SIZE             (1 << PCPU_MIN_ALLOC_SHIFT)
  29
  30 /*
  31  * The PCPU_BITMAP_BLOCK_SIZE must be the same size as PAGE_SIZE as the
  32  * updating of hints is used to manage the nr_empty_pop_pages in both
  33  * the chunk and globally.
  34  */
  35 #define PCPU_BITMAP_BLOCK_SIZE          PAGE_SIZE
  36 #define PCPU_BITMAP_BLOCK_BITS          (PCPU_BITMAP_BLOCK_SIZE >>      \
  37                                          PCPU_MIN_ALLOC_SHIFT)
  38
  39 #ifdef CONFIG_RANDOM_KMALLOC_CACHES
  40 # if defined(CONFIG_LOCKDEP) && !defined(CONFIG_PAGE_SIZE_4KB)
  41 # define PERCPU_DYNAMIC_SIZE_SHIFT      13
  42 # else
  43 # define PERCPU_DYNAMIC_SIZE_SHIFT      12
  44 #endif /* LOCKDEP and PAGE_SIZE > 4KiB */
  45 #else
  46 #define PERCPU_DYNAMIC_SIZE_SHIFT      10
  47 #endif
  48
  49 /*
  50  * Percpu allocator can serve percpu allocations before slab is
  51  * initialized which allows slab to depend on the percpu allocator.
  52  * The following parameter decide how much resource to preallocate
  53  * for this.  Keep PERCPU_DYNAMIC_RESERVE equal to or larger than
  54  * PERCPU_DYNAMIC_EARLY_SIZE.
  55  */
  56 #define PERCPU_DYNAMIC_EARLY_SIZE       (20 << PERCPU_DYNAMIC_SIZE_SHIFT)
  57
  58 /*
  59  * PERCPU_DYNAMIC_RESERVE indicates the amount of free area to piggy
  60  * back on the first chunk for dynamic percpu allocation if arch is
  61  * manually allocating and mapping it for faster access (as a part of
  62  * large page mapping for example).
  63  *
  64  * The following values give between one and two pages of free space
  65  * after typical minimal boot (2-way SMP, single disk and NIC) with
  66  * both defconfig and a distro config on x86_64 and 32.  More
  67  * intelligent way to determine this would be nice.
  68  */
  69 #if BITS_PER_LONG > 32
  70 #define PERCPU_DYNAMIC_RESERVE          (28 << PERCPU_DYNAMIC_SIZE_SHIFT)
  71 #else
  72 #define PERCPU_DYNAMIC_RESERVE          (20 << PERCPU_DYNAMIC_SIZE_SHIFT)
  73 #endif
  74
  75 extern void *pcpu_base_addr;
  76 extern const unsigned long *pcpu_unit_offsets;
  77
  78 struct pcpu_group_info {
  79         int                     nr_units;       /* aligned # of units */
  80         unsigned long           base_offset;    /* base address offset */
  81         unsigned int            *cpu_map;       /* unit->cpu map, empty
  82                                                  * entries contain NR_CPUS */
  83 };
  84
  85 struct pcpu_alloc_info {
  86         size_t                  static_size;
  87         size_t                  reserved_size;
  88         size_t                  dyn_size;
  89         size_t                  unit_size;
  90         size_t                  atom_size;
  91         size_t                  alloc_size;
  92         size_t                  __ai_size;      /* internal, don't use */
  93         int                     nr_groups;      /* 0 if grouping unnecessary */
  94         struct pcpu_group_info  groups[];
  95 };
  96
  97 enum pcpu_fc {
  98         PCPU_FC_AUTO,
  99         PCPU_FC_EMBED,
 100         PCPU_FC_PAGE,
 101
 102         PCPU_FC_NR,
 103 };
 104 extern const char * const pcpu_fc_names[PCPU_FC_NR];
 105
 106 extern enum pcpu_fc pcpu_chosen_fc;
 107
 108 typedef int (pcpu_fc_cpu_to_node_fn_t)(int cpu);
 109 typedef int (pcpu_fc_cpu_distance_fn_t)(unsigned int from, unsigned int to);
 110
 111 extern struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
 112                                                              int nr_units);
 113 extern void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai);
 114
 115 extern void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
 116                                          void *base_addr);
 117
 118 extern int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
 119                                 size_t atom_size,
 120                                 pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
 121                                 pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn);
 122
 123 #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
 124 void __init pcpu_populate_pte(unsigned long addr);
 125 extern int __init pcpu_page_first_chunk(size_t reserved_size,
 126                                 pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn);
 127 #endif
 128
 129 extern bool __is_kernel_percpu_address(unsigned long addr, unsigned long *can_addr);
 130 extern bool is_kernel_percpu_address(unsigned long addr);
 131
 132 #if !defined(CONFIG_SMP) || !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
 133 extern void __init setup_per_cpu_areas(void);
 134 #endif
 135
 136 extern void __percpu *pcpu_alloc_noprof(size_t size, size_t align, bool reserved,
 137                                    gfp_t gfp) __alloc_size(1);
 138
 139 #define __alloc_percpu_gfp(_size, _align, _gfp)                         \
 140         alloc_hooks(pcpu_alloc_noprof(_size, _align, false, _gfp))
 141 #define __alloc_percpu(_size, _align)                                   \
 142         alloc_hooks(pcpu_alloc_noprof(_size, _align, false, GFP_KERNEL))
 143 #define __alloc_reserved_percpu(_size, _align)                          \
 144         alloc_hooks(pcpu_alloc_noprof(_size, _align, true, GFP_KERNEL))
 145
 146 #define alloc_percpu_gfp(type, gfp)                                     \
 147         (typeof(type) __percpu *)__alloc_percpu_gfp(sizeof(type),       \
 148                                                 __alignof__(type), gfp)
 149 #define alloc_percpu(type)                                              \
 150         (typeof(type) __percpu *)__alloc_percpu(sizeof(type),           \
 151                                                 __alignof__(type))
 152 #define alloc_percpu_noprof(type)                                       \
 153         ((typeof(type) __percpu *)pcpu_alloc_noprof(sizeof(type),       \
 154                                         __alignof__(type), false, GFP_KERNEL))
 155
 156 extern void free_percpu(void __percpu *__pdata);
 157
 158 DEFINE_FREE(free_percpu, void __percpu *, free_percpu(_T))
 159
 160 extern phys_addr_t per_cpu_ptr_to_phys(void *addr);
 161
 162 extern unsigned long pcpu_nr_pages(void);
 163
 164 #endif /* __LINUX_PERCPU_H */