Linux kernel mirror (for testing)
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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 */