1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __LINUX_PERCPU_H
3 #define __LINUX_PERCPU_H
5 #include <linux/mmdebug.h>
6 #include <linux/preempt.h>
8 #include <linux/cpumask.h>
10 #include <linux/init.h>
12 #include <asm/percpu.h>
14 /* enough to cover all DEFINE_PER_CPUs in modules */
16 #define PERCPU_MODULE_RESERVE (8 << 10)
18 #define PERCPU_MODULE_RESERVE 0
21 /* minimum unit size, also is the maximum supported allocation size */
22 #define PCPU_MIN_UNIT_SIZE PFN_ALIGN(32 << 10)
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)
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.
33 #define PCPU_BITMAP_BLOCK_SIZE PAGE_SIZE
34 #define PCPU_BITMAP_BLOCK_BITS (PCPU_BITMAP_BLOCK_SIZE >> \
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.
44 #define PERCPU_DYNAMIC_EARLY_SIZE (20 << 10)
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).
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.
57 #if BITS_PER_LONG > 32
58 #define PERCPU_DYNAMIC_RESERVE (28 << 10)
60 #define PERCPU_DYNAMIC_RESERVE (20 << 10)
63 extern void *pcpu_base_addr;
64 extern const unsigned long *pcpu_unit_offsets;
66 struct 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 */
73 struct pcpu_alloc_info {
80 size_t __ai_size; /* internal, don't use */
81 int nr_groups; /* 0 if grouping unnecessary */
82 struct pcpu_group_info groups[];
92 extern const char * const pcpu_fc_names[PCPU_FC_NR];
94 extern enum pcpu_fc pcpu_chosen_fc;
96 typedef int (pcpu_fc_cpu_to_node_fn_t)(int cpu);
97 typedef int (pcpu_fc_cpu_distance_fn_t)(unsigned int from, unsigned int to);
99 extern struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
101 extern void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai);
103 extern void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
106 #ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
107 extern int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
109 pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
110 pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn);
113 #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
114 void __init pcpu_populate_pte(unsigned long addr);
115 extern int __init pcpu_page_first_chunk(size_t reserved_size,
116 pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn);
119 extern void __percpu *__alloc_reserved_percpu(size_t size, size_t align) __alloc_size(1);
120 extern bool __is_kernel_percpu_address(unsigned long addr, unsigned long *can_addr);
121 extern bool is_kernel_percpu_address(unsigned long addr);
123 #if !defined(CONFIG_SMP) || !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
124 extern void __init setup_per_cpu_areas(void);
127 extern void __percpu *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp) __alloc_size(1);
128 extern void __percpu *__alloc_percpu(size_t size, size_t align) __alloc_size(1);
129 extern void free_percpu(void __percpu *__pdata);
130 extern phys_addr_t per_cpu_ptr_to_phys(void *addr);
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), \
139 extern unsigned long pcpu_nr_pages(void);
141 #endif /* __LINUX_PERCPU_H */