percpu.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef __LINUX_PERCPU_H
  3#define __LINUX_PERCPU_H
  4
  5#include <linux/alloc_tag.h>
  6#include <linux/mmdebug.h>
  7#include <linux/preempt.h>
  8#include <linux/smp.h>
  9#include <linux/pfn.h>
 10#include <linux/init.h>
 11#include <linux/cleanup.h>
 12#include <linux/sched.h>
 13
 14#include <asm/percpu.h>
 15
 16/* enough to cover all DEFINE_PER_CPUs in modules */
 17#ifdef CONFIG_MODULES
 18#define PERCPU_MODULE_RESERVE		(8 << 10)
 19#else
 20#define PERCPU_MODULE_RESERVE		0
 21#endif
 22
 23/* minimum unit size, also is the maximum supported allocation size */
 24#define PCPU_MIN_UNIT_SIZE		PFN_ALIGN(32 << 10)
 25
 26/* minimum allocation size and shift in bytes */
 27#define PCPU_MIN_ALLOC_SHIFT		2
 28#define PCPU_MIN_ALLOC_SIZE		(1 << PCPU_MIN_ALLOC_SHIFT)
 29
 30/*
 31 * The PCPU_BITMAP_BLOCK_SIZE must be the same size as PAGE_SIZE as the
 32 * updating of hints is used to manage the nr_empty_pop_pages in both
 33 * the chunk and globally.
 34 */
 35#define PCPU_BITMAP_BLOCK_SIZE		PAGE_SIZE
 36#define PCPU_BITMAP_BLOCK_BITS		(PCPU_BITMAP_BLOCK_SIZE >>	\
 37					 PCPU_MIN_ALLOC_SHIFT)
 38
 39#ifdef CONFIG_RANDOM_KMALLOC_CACHES
 40# if defined(CONFIG_LOCKDEP) && !defined(CONFIG_PAGE_SIZE_4KB)
 41# define PERCPU_DYNAMIC_SIZE_SHIFT      13
 42# else
 43# define PERCPU_DYNAMIC_SIZE_SHIFT      12
 44#endif /* LOCKDEP and PAGE_SIZE > 4KiB */
 45#else
 46#define PERCPU_DYNAMIC_SIZE_SHIFT      10
 47#endif
 48
 49/*
 50 * Percpu allocator can serve percpu allocations before slab is
 51 * initialized which allows slab to depend on the percpu allocator.
 52 * The following parameter decide how much resource to preallocate
 53 * for this.  Keep PERCPU_DYNAMIC_RESERVE equal to or larger than
 54 * PERCPU_DYNAMIC_EARLY_SIZE.
 55 */
 56#define PERCPU_DYNAMIC_EARLY_SIZE	(20 << PERCPU_DYNAMIC_SIZE_SHIFT)
 57
 58/*
 59 * PERCPU_DYNAMIC_RESERVE indicates the amount of free area to piggy
 60 * back on the first chunk for dynamic percpu allocation if arch is
 61 * manually allocating and mapping it for faster access (as a part of
 62 * large page mapping for example).
 63 *
 64 * The following values give between one and two pages of free space
 65 * after typical minimal boot (2-way SMP, single disk and NIC) with
 66 * both defconfig and a distro config on x86_64 and 32.  More
 67 * intelligent way to determine this would be nice.
 68 */
 69#if BITS_PER_LONG > 32
 70#define PERCPU_DYNAMIC_RESERVE		(28 << PERCPU_DYNAMIC_SIZE_SHIFT)
 71#else
 72#define PERCPU_DYNAMIC_RESERVE		(20 << PERCPU_DYNAMIC_SIZE_SHIFT)
 73#endif
 74
 75extern void *pcpu_base_addr;
 76extern const unsigned long *pcpu_unit_offsets;
 77
 78struct pcpu_group_info {
 79	int			nr_units;	/* aligned # of units */
 80	unsigned long		base_offset;	/* base address offset */
 81	unsigned int		*cpu_map;	/* unit->cpu map, empty
 82						 * entries contain NR_CPUS */
 83};
 84
 85struct pcpu_alloc_info {
 86	size_t			static_size;
 87	size_t			reserved_size;
 88	size_t			dyn_size;
 89	size_t			unit_size;
 90	size_t			atom_size;
 91	size_t			alloc_size;
 92	size_t			__ai_size;	/* internal, don't use */
 93	int			nr_groups;	/* 0 if grouping unnecessary */
 94	struct pcpu_group_info	groups[];
 95};
 96
 97enum pcpu_fc {
 98	PCPU_FC_AUTO,
 99	PCPU_FC_EMBED,
100	PCPU_FC_PAGE,
101
102	PCPU_FC_NR,
103};
104extern const char * const pcpu_fc_names[PCPU_FC_NR];
105
106extern enum pcpu_fc pcpu_chosen_fc;
107
108typedef int (pcpu_fc_cpu_to_node_fn_t)(int cpu);
109typedef int (pcpu_fc_cpu_distance_fn_t)(unsigned int from, unsigned int to);
110
111extern struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
112							     int nr_units);
113extern void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai);
114
115extern void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
116					 void *base_addr);
117
118extern int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
119				size_t atom_size,
120				pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
121				pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn);
122
123#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
124void __init pcpu_populate_pte(unsigned long addr);
125extern int __init pcpu_page_first_chunk(size_t reserved_size,
126				pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn);
127#endif
128
129extern bool __is_kernel_percpu_address(unsigned long addr, unsigned long *can_addr);
130extern bool is_kernel_percpu_address(unsigned long addr);
131
132#if !defined(CONFIG_SMP) || !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
133extern void __init setup_per_cpu_areas(void);
134#endif
135
136extern void __percpu *pcpu_alloc_noprof(size_t size, size_t align, bool reserved,
137				   gfp_t gfp) __alloc_size(1);
138
139#define __alloc_percpu_gfp(_size, _align, _gfp)				\
140	alloc_hooks(pcpu_alloc_noprof(_size, _align, false, _gfp))
141#define __alloc_percpu(_size, _align)					\
142	alloc_hooks(pcpu_alloc_noprof(_size, _align, false, GFP_KERNEL))
143#define __alloc_reserved_percpu(_size, _align)				\
144	alloc_hooks(pcpu_alloc_noprof(_size, _align, true, GFP_KERNEL))
145
146#define alloc_percpu_gfp(type, gfp)					\
147	(typeof(type) __percpu *)__alloc_percpu_gfp(sizeof(type),	\
148						__alignof__(type), gfp)
149#define alloc_percpu(type)						\
150	(typeof(type) __percpu *)__alloc_percpu(sizeof(type),		\
151						__alignof__(type))
152#define alloc_percpu_noprof(type)					\
153	((typeof(type) __percpu *)pcpu_alloc_noprof(sizeof(type),	\
154					__alignof__(type), false, GFP_KERNEL))
155
156extern void free_percpu(void __percpu *__pdata);
157
158DEFINE_FREE(free_percpu, void __percpu *, free_percpu(_T))
159
160extern phys_addr_t per_cpu_ptr_to_phys(void *addr);
161
162extern unsigned long pcpu_nr_pages(void);
163
164#endif /* __LINUX_PERCPU_H */