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