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