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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * include/linux/memory.h - generic memory definition
4 *
5 * This is mainly for topological representation. We define the
6 * basic "struct memory_block" here, which can be embedded in per-arch
7 * definitions or NUMA information.
8 *
9 * Basic handling of the devices is done in drivers/base/memory.c
10 * and system devices are handled in drivers/base/sys.c.
11 *
12 * Memory block are exported via sysfs in the class/memory/devices/
13 * directory.
14 *
15 */
16#ifndef _LINUX_MEMORY_H_
17#define _LINUX_MEMORY_H_
18
19#include <linux/node.h>
20#include <linux/compiler.h>
21#include <linux/mutex.h>
22
23#define MIN_MEMORY_BLOCK_SIZE (1UL << SECTION_SIZE_BITS)
24
25/**
26 * struct memory_group - a logical group of memory blocks
27 * @nid: The node id for all memory blocks inside the memory group.
28 * @memory_blocks: List of all memory blocks belonging to this memory group.
29 * @present_kernel_pages: Present (online) memory outside ZONE_MOVABLE of this
30 * memory group.
31 * @present_movable_pages: Present (online) memory in ZONE_MOVABLE of this
32 * memory group.
33 * @is_dynamic: The memory group type: static vs. dynamic
34 * @s.max_pages: Valid with &memory_group.is_dynamic == false. The maximum
35 * number of pages we'll have in this static memory group.
36 * @d.unit_pages: Valid with &memory_group.is_dynamic == true. Unit in pages
37 * in which memory is added/removed in this dynamic memory group.
38 * This granularity defines the alignment of a unit in physical
39 * address space; it has to be at least as big as a single
40 * memory block.
41 *
42 * A memory group logically groups memory blocks; each memory block
43 * belongs to at most one memory group. A memory group corresponds to
44 * a memory device, such as a DIMM or a NUMA node, which spans multiple
45 * memory blocks and might even span multiple non-contiguous physical memory
46 * ranges.
47 *
48 * Modification of members after registration is serialized by memory
49 * hot(un)plug code.
50 */
51struct memory_group {
52 int nid;
53 struct list_head memory_blocks;
54 unsigned long present_kernel_pages;
55 unsigned long present_movable_pages;
56 bool is_dynamic;
57 union {
58 struct {
59 unsigned long max_pages;
60 } s;
61 struct {
62 unsigned long unit_pages;
63 } d;
64 };
65};
66
67enum memory_block_state {
68 /* These states are exposed to userspace as text strings in sysfs */
69 MEM_ONLINE, /* exposed to userspace */
70 MEM_GOING_OFFLINE, /* exposed to userspace */
71 MEM_OFFLINE, /* exposed to userspace */
72 MEM_GOING_ONLINE,
73 MEM_CANCEL_ONLINE,
74 MEM_CANCEL_OFFLINE,
75};
76
77struct memory_block {
78 unsigned long start_section_nr;
79 enum memory_block_state state; /* serialized by the dev->lock */
80 int online_type; /* for passing data to online routine */
81 int nid; /* NID for this memory block */
82 /*
83 * The single zone of this memory block if all PFNs of this memory block
84 * that are System RAM (not a memory hole, not ZONE_DEVICE ranges) are
85 * managed by a single zone. NULL if multiple zones (including nodes)
86 * apply.
87 */
88 struct zone *zone;
89 struct device dev;
90 struct vmem_altmap *altmap;
91 struct memory_group *group; /* group (if any) for this block */
92 struct list_head group_next; /* next block inside memory group */
93#if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_MEMORY_HOTPLUG)
94 atomic_long_t nr_hwpoison;
95#endif
96};
97
98int arch_get_memory_phys_device(unsigned long start_pfn);
99unsigned long memory_block_size_bytes(void);
100int set_memory_block_size_order(unsigned int order);
101
102struct memory_notify {
103 unsigned long start_pfn;
104 unsigned long nr_pages;
105};
106
107struct notifier_block;
108struct mem_section;
109
110/*
111 * Priorities for the hotplug memory callback routines. Invoked from
112 * high to low. Higher priorities correspond to higher numbers.
113 */
114#define DEFAULT_CALLBACK_PRI 0
115#define SLAB_CALLBACK_PRI 1
116#define CXL_CALLBACK_PRI 5
117#define HMAT_CALLBACK_PRI 6
118#define MM_COMPUTE_BATCH_PRI 10
119#define CPUSET_CALLBACK_PRI 10
120#define MEMTIER_HOTPLUG_PRI 100
121#define KSM_CALLBACK_PRI 100
122
123#ifndef CONFIG_MEMORY_HOTPLUG
124static inline void memory_dev_init(void)
125{
126 return;
127}
128static inline int register_memory_notifier(struct notifier_block *nb)
129{
130 return 0;
131}
132static inline void unregister_memory_notifier(struct notifier_block *nb)
133{
134}
135static inline int memory_notify(enum memory_block_state state, void *v)
136{
137 return 0;
138}
139static inline int hotplug_memory_notifier(notifier_fn_t fn, int pri)
140{
141 return 0;
142}
143static inline int memory_block_advise_max_size(unsigned long size)
144{
145 return -ENODEV;
146}
147static inline unsigned long memory_block_advised_max_size(void)
148{
149 return 0;
150}
151#else /* CONFIG_MEMORY_HOTPLUG */
152extern int register_memory_notifier(struct notifier_block *nb);
153extern void unregister_memory_notifier(struct notifier_block *nb);
154int create_memory_block_devices(unsigned long start, unsigned long size,
155 int nid, struct vmem_altmap *altmap,
156 struct memory_group *group);
157void remove_memory_block_devices(unsigned long start, unsigned long size);
158extern void memory_dev_init(void);
159extern int memory_notify(enum memory_block_state state, void *v);
160extern struct memory_block *find_memory_block(unsigned long section_nr);
161typedef int (*walk_memory_blocks_func_t)(struct memory_block *, void *);
162extern int walk_memory_blocks(unsigned long start, unsigned long size,
163 void *arg, walk_memory_blocks_func_t func);
164extern int for_each_memory_block(void *arg, walk_memory_blocks_func_t func);
165
166extern int memory_group_register_static(int nid, unsigned long max_pages);
167extern int memory_group_register_dynamic(int nid, unsigned long unit_pages);
168extern int memory_group_unregister(int mgid);
169struct memory_group *memory_group_find_by_id(int mgid);
170typedef int (*walk_memory_groups_func_t)(struct memory_group *, void *);
171int walk_dynamic_memory_groups(int nid, walk_memory_groups_func_t func,
172 struct memory_group *excluded, void *arg);
173struct memory_block *find_memory_block_by_id(unsigned long block_id);
174#define hotplug_memory_notifier(fn, pri) ({ \
175 static __meminitdata struct notifier_block fn##_mem_nb =\
176 { .notifier_call = fn, .priority = pri };\
177 register_memory_notifier(&fn##_mem_nb); \
178})
179
180extern int sections_per_block;
181
182static inline unsigned long memory_block_id(unsigned long section_nr)
183{
184 return section_nr / sections_per_block;
185}
186
187static inline unsigned long pfn_to_block_id(unsigned long pfn)
188{
189 return memory_block_id(section_nr: pfn_to_section_nr(pfn));
190}
191
192static inline unsigned long phys_to_block_id(unsigned long phys)
193{
194 return pfn_to_block_id(PFN_DOWN(phys));
195}
196
197#ifdef CONFIG_NUMA
198void memory_block_add_nid_early(struct memory_block *mem, int nid);
199#endif /* CONFIG_NUMA */
200int memory_block_advise_max_size(unsigned long size);
201unsigned long memory_block_advised_max_size(void);
202#endif /* CONFIG_MEMORY_HOTPLUG */
203
204/*
205 * Kernel text modification mutex, used for code patching. Users of this lock
206 * can sleep.
207 */
208extern struct mutex text_mutex;
209
210#endif /* _LINUX_MEMORY_H_ */
211

source code of linux/include/linux/memory.h