memory.h

  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(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_ */