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#include <linux/notifier.h>
23
24#define MIN_MEMORY_BLOCK_SIZE (1UL << SECTION_SIZE_BITS)
25
26/**
27 * struct memory_group - a logical group of memory blocks
28 * @nid: The node id for all memory blocks inside the memory group.
29 * @blocks: List of all memory blocks belonging to this memory group.
30 * @present_kernel_pages: Present (online) memory outside ZONE_MOVABLE of this
31 * memory group.
32 * @present_movable_pages: Present (online) memory in ZONE_MOVABLE of this
33 * memory group.
34 * @is_dynamic: The memory group type: static vs. dynamic
35 * @s.max_pages: Valid with &memory_group.is_dynamic == false. The maximum
36 * number of pages we'll have in this static memory group.
37 * @d.unit_pages: Valid with &memory_group.is_dynamic == true. Unit in pages
38 * in which memory is added/removed in this dynamic memory group.
39 * This granularity defines the alignment of a unit in physical
40 * address space; it has to be at least as big as a single
41 * memory block.
42 *
43 * A memory group logically groups memory blocks; each memory block
44 * belongs to at most one memory group. A memory group corresponds to
45 * a memory device, such as a DIMM or a NUMA node, which spans multiple
46 * memory blocks and might even span multiple non-contiguous physical memory
47 * ranges.
48 *
49 * Modification of members after registration is serialized by memory
50 * hot(un)plug code.
51 */
52struct memory_group {
53 int nid;
54 struct list_head memory_blocks;
55 unsigned long present_kernel_pages;
56 unsigned long present_movable_pages;
57 bool is_dynamic;
58 union {
59 struct {
60 unsigned long max_pages;
61 } s;
62 struct {
63 unsigned long unit_pages;
64 } d;
65 };
66};
67
68struct memory_block {
69 unsigned long start_section_nr;
70 unsigned long state; /* serialized by the dev->lock */
71 int online_type; /* for passing data to online routine */
72 int nid; /* NID for this memory block */
73 /*
74 * The single zone of this memory block if all PFNs of this memory block
75 * that are System RAM (not a memory hole, not ZONE_DEVICE ranges) are
76 * managed by a single zone. NULL if multiple zones (including nodes)
77 * apply.
78 */
79 struct zone *zone;
80 struct device dev;
81 /*
82 * Number of vmemmap pages. These pages
83 * lay at the beginning of the memory block.
84 */
85 unsigned long nr_vmemmap_pages;
86 struct memory_group *group; /* group (if any) for this block */
87 struct list_head group_next; /* next block inside memory group */
88};
89
90int arch_get_memory_phys_device(unsigned long start_pfn);
91unsigned long memory_block_size_bytes(void);
92int set_memory_block_size_order(unsigned int order);
93
94/* These states are exposed to userspace as text strings in sysfs */
95#define MEM_ONLINE (1<<0) /* exposed to userspace */
96#define MEM_GOING_OFFLINE (1<<1) /* exposed to userspace */
97#define MEM_OFFLINE (1<<2) /* exposed to userspace */
98#define MEM_GOING_ONLINE (1<<3)
99#define MEM_CANCEL_ONLINE (1<<4)
100#define MEM_CANCEL_OFFLINE (1<<5)
101
102struct memory_notify {
103 unsigned long start_pfn;
104 unsigned long nr_pages;
105 int status_change_nid_normal;
106 int status_change_nid;
107};
108
109struct notifier_block;
110struct mem_section;
111
112/*
113 * Priorities for the hotplug memory callback routines (stored in decreasing
114 * order in the callback chain)
115 */
116#define SLAB_CALLBACK_PRI 1
117#define IPC_CALLBACK_PRI 10
118
119#ifndef CONFIG_MEMORY_HOTPLUG
120static inline void memory_dev_init(void)
121{
122 return;
123}
124static inline int register_memory_notifier(struct notifier_block *nb)
125{
126 return 0;
127}
128static inline void unregister_memory_notifier(struct notifier_block *nb)
129{
130}
131static inline int memory_notify(unsigned long val, void *v)
132{
133 return 0;
134}
135static inline int hotplug_memory_notifier(notifier_fn_t fn, int pri)
136{
137 return 0;
138}
139/* These aren't inline functions due to a GCC bug. */
140#define register_hotmemory_notifier(nb) ({ (void)(nb); 0; })
141#define unregister_hotmemory_notifier(nb) ({ (void)(nb); })
142#else /* CONFIG_MEMORY_HOTPLUG */
143extern int register_memory_notifier(struct notifier_block *nb);
144extern void unregister_memory_notifier(struct notifier_block *nb);
145int create_memory_block_devices(unsigned long start, unsigned long size,
146 unsigned long vmemmap_pages,
147 struct memory_group *group);
148void remove_memory_block_devices(unsigned long start, unsigned long size);
149extern void memory_dev_init(void);
150extern int memory_notify(unsigned long val, void *v);
151extern struct memory_block *find_memory_block(unsigned long section_nr);
152typedef int (*walk_memory_blocks_func_t)(struct memory_block *, void *);
153extern int walk_memory_blocks(unsigned long start, unsigned long size,
154 void *arg, walk_memory_blocks_func_t func);
155extern int for_each_memory_block(void *arg, walk_memory_blocks_func_t func);
156
157extern int memory_group_register_static(int nid, unsigned long max_pages);
158extern int memory_group_register_dynamic(int nid, unsigned long unit_pages);
159extern int memory_group_unregister(int mgid);
160struct memory_group *memory_group_find_by_id(int mgid);
161typedef int (*walk_memory_groups_func_t)(struct memory_group *, void *);
162int walk_dynamic_memory_groups(int nid, walk_memory_groups_func_t func,
163 struct memory_group *excluded, void *arg);
164#define hotplug_memory_notifier(fn, pri) ({ \
165 static __meminitdata struct notifier_block fn##_mem_nb =\
166 { .notifier_call = fn, .priority = pri };\
167 register_memory_notifier(&fn##_mem_nb); \
168})
169#define register_hotmemory_notifier(nb) register_memory_notifier(nb)
170#define unregister_hotmemory_notifier(nb) unregister_memory_notifier(nb)
171
172#ifdef CONFIG_NUMA
173void memory_block_add_nid(struct memory_block *mem, int nid,
174 enum meminit_context context);
175#endif /* CONFIG_NUMA */
176#endif /* CONFIG_MEMORY_HOTPLUG */
177
178/*
179 * Kernel text modification mutex, used for code patching. Users of this lock
180 * can sleep.
181 */
182extern struct mutex text_mutex;
183
184#endif /* _LINUX_MEMORY_H_ */
185

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