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 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.
44 #define PERCPU_DYNAMIC_EARLY_SLOTS 128
45 #define PERCPU_DYNAMIC_EARLY_SIZE (12 << 10)
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).
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.
58 #if BITS_PER_LONG > 32
59 #define PERCPU_DYNAMIC_RESERVE (28 << 10)
61 #define PERCPU_DYNAMIC_RESERVE (20 << 10)
64 extern void *pcpu_base_addr;
65 extern const unsigned long *pcpu_unit_offsets;
67 struct 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 */
74 struct pcpu_alloc_info {
81 size_t __ai_size; /* internal, don't use */
82 int nr_groups; /* 0 if grouping unnecessary */
83 struct pcpu_group_info groups[];
93 extern const char * const pcpu_fc_names[PCPU_FC_NR];
95 extern enum pcpu_fc pcpu_chosen_fc;
97 typedef int (pcpu_fc_cpu_to_node_fn_t)(int cpu);
98 typedef int (pcpu_fc_cpu_distance_fn_t)(unsigned int from, unsigned int to);
100 extern struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
102 extern void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai);
104 extern void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
107 #ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
108 extern int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
110 pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
111 pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn);
114 #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
115 void __init pcpu_populate_pte(unsigned long addr);
116 extern int __init pcpu_page_first_chunk(size_t reserved_size,
117 pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn);
120 extern void __percpu *__alloc_reserved_percpu(size_t size, size_t align) __alloc_size(1);
121 extern bool __is_kernel_percpu_address(unsigned long addr, unsigned long *can_addr);
122 extern bool is_kernel_percpu_address(unsigned long addr);
124 #if !defined(CONFIG_SMP) || !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
125 extern void __init setup_per_cpu_areas(void);
128 extern void __percpu *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp) __alloc_size(1);
129 extern void __percpu *__alloc_percpu(size_t size, size_t align) __alloc_size(1);
130 extern void free_percpu(void __percpu *__pdata);
131 extern phys_addr_t per_cpu_ptr_to_phys(void *addr);
133 #define alloc_percpu_gfp(type, gfp) \
134 (typeof(type) __percpu *)__alloc_percpu_gfp(sizeof(type), \
135 __alignof__(type), gfp)
136 #define alloc_percpu(type) \
137 (typeof(type) __percpu *)__alloc_percpu(sizeof(type), \
140 extern unsigned long pcpu_nr_pages(void);
142 #endif /* __LINUX_PERCPU_H */