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 * @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 */
51 struct 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
67 struct memory_block {
68 unsigned long start_section_nr;
69 unsigned long state; /* serialized by the dev->lock */
70 int online_type; /* for passing data to online routine */
71 int nid; /* NID for this memory block */
72 /*
73 * The single zone of this memory block if all PFNs of this memory block
74 * that are System RAM (not a memory hole, not ZONE_DEVICE ranges) are
75 * managed by a single zone. NULL if multiple zones (including nodes)
76 * apply.
77 */
78 struct zone *zone;
79 struct device dev;
80 struct vmem_altmap *altmap;
81 struct memory_group *group; /* group (if any) for this block */
82 struct list_head group_next; /* next block inside memory group */
83 #if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_MEMORY_HOTPLUG)
84 atomic_long_t nr_hwpoison;
85 #endif
86 };
87
88 int arch_get_memory_phys_device(unsigned long start_pfn);
89 unsigned long memory_block_size_bytes(void);
90 int set_memory_block_size_order(unsigned int order);
91
92 /* These states are exposed to userspace as text strings in sysfs */
93 #define MEM_ONLINE (1<<0) /* exposed to userspace */
94 #define MEM_GOING_OFFLINE (1<<1) /* exposed to userspace */
95 #define MEM_OFFLINE (1<<2) /* exposed to userspace */
96 #define MEM_GOING_ONLINE (1<<3)
97 #define MEM_CANCEL_ONLINE (1<<4)
98 #define MEM_CANCEL_OFFLINE (1<<5)
99 #define MEM_PREPARE_ONLINE (1<<6)
100 #define MEM_FINISH_OFFLINE (1<<7)
101
102 struct memory_notify {
103 /*
104 * The altmap_start_pfn and altmap_nr_pages fields are designated for
105 * specifying the altmap range and are exclusively intended for use in
106 * MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE notifiers.
107 */
108 unsigned long altmap_start_pfn;
109 unsigned long altmap_nr_pages;
110 unsigned long start_pfn;
111 unsigned long nr_pages;
112 int status_change_nid_normal;
113 int status_change_nid;
114 };
115
116 struct notifier_block;
117 struct mem_section;
118
119 /*
120 * Priorities for the hotplug memory callback routines (stored in decreasing
121 * order in the callback chain)
122 */
123 #define DEFAULT_CALLBACK_PRI 0
124 #define SLAB_CALLBACK_PRI 1
125 #define HMAT_CALLBACK_PRI 2
126 #define CXL_CALLBACK_PRI 5
127 #define MM_COMPUTE_BATCH_PRI 10
128 #define CPUSET_CALLBACK_PRI 10
129 #define MEMTIER_HOTPLUG_PRI 100
130 #define KSM_CALLBACK_PRI 100
131
132 #ifndef CONFIG_MEMORY_HOTPLUG
133 static inline void memory_dev_init(void)
134 {
135 return;
136 }
137 static inline int register_memory_notifier(struct notifier_block *nb)
138 {
139 return 0;
140 }
141 static inline void unregister_memory_notifier(struct notifier_block *nb)
142 {
143 }
144 static inline int memory_notify(unsigned long val, void *v)
145 {
146 return 0;
147 }
148 static inline int hotplug_memory_notifier(notifier_fn_t fn, int pri)
149 {
150 return 0;
151 }
152 #else /* CONFIG_MEMORY_HOTPLUG */
153 extern int register_memory_notifier(struct notifier_block *nb);
154 extern void unregister_memory_notifier(struct notifier_block *nb);
155 int create_memory_block_devices(unsigned long start, unsigned long size,
156 struct vmem_altmap *altmap,
157 struct memory_group *group);
158 void remove_memory_block_devices(unsigned long start, unsigned long size);
159 extern void memory_dev_init(void);
160 extern int memory_notify(unsigned long val, void *v);
161 extern struct memory_block *find_memory_block(unsigned long section_nr);
162 typedef int (*walk_memory_blocks_func_t)(struct memory_block *, void *);
163 extern int walk_memory_blocks(unsigned long start, unsigned long size,
164 void *arg, walk_memory_blocks_func_t func);
165 extern int for_each_memory_block(void *arg, walk_memory_blocks_func_t func);
166
167 extern int memory_group_register_static(int nid, unsigned long max_pages);
168 extern int memory_group_register_dynamic(int nid, unsigned long unit_pages);
169 extern int memory_group_unregister(int mgid);
170 struct memory_group *memory_group_find_by_id(int mgid);
171 typedef int (*walk_memory_groups_func_t)(struct memory_group *, void *);
172 int walk_dynamic_memory_groups(int nid, walk_memory_groups_func_t func,
173 struct memory_group *excluded, void *arg);
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
180 #ifdef CONFIG_NUMA
181 void memory_block_add_nid(struct memory_block *mem, int nid,
182 enum meminit_context context);
183 #endif /* CONFIG_NUMA */
184 #endif /* CONFIG_MEMORY_HOTPLUG */
185
186 /*
187 * Kernel text modification mutex, used for code patching. Users of this lock
188 * can sleep.
189 */
190 extern struct mutex text_mutex;
191
192 #endif /* _LINUX_MEMORY_H_ */
193
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