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