include/linux/memory_hotplug.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __LINUX_MEMORY_HOTPLUG_H
   3 #define __LINUX_MEMORY_HOTPLUG_H
   4
   5 #include <linux/mmzone.h>
   6 #include <linux/spinlock.h>
   7 #include <linux/notifier.h>
   8 #include <linux/bug.h>
   9
  10 struct page;
  11 struct zone;
  12 struct pglist_data;
  13 struct mem_section;
  14 struct memory_group;
  15 struct resource;
  16 struct vmem_altmap;
  17 struct dev_pagemap;
  18
  19 #ifdef CONFIG_MEMORY_HOTPLUG
  20 struct page *pfn_to_online_page(unsigned long pfn);
  21
  22 /* Types for control the zone type of onlined and offlined memory */
  23 enum {
  24         /* Offline the memory. */
  25         MMOP_OFFLINE = 0,
  26         /* Online the memory. Zone depends, see default_zone_for_pfn(). */
  27         MMOP_ONLINE,
  28         /* Online the memory to ZONE_NORMAL. */
  29         MMOP_ONLINE_KERNEL,
  30         /* Online the memory to ZONE_MOVABLE. */
  31         MMOP_ONLINE_MOVABLE,
  32 };
  33
  34 /* Flags for add_memory() and friends to specify memory hotplug details. */
  35 typedef int __bitwise mhp_t;
  36
  37 /* No special request */
  38 #define MHP_NONE                ((__force mhp_t)0)
  39 /*
  40  * Allow merging of the added System RAM resource with adjacent,
  41  * mergeable resources. After a successful call to add_memory_resource()
  42  * with this flag set, the resource pointer must no longer be used as it
  43  * might be stale, or the resource might have changed.
  44  */
  45 #define MHP_MERGE_RESOURCE      ((__force mhp_t)BIT(0))
  46
  47 /*
  48  * We want memmap (struct page array) to be self contained.
  49  * To do so, we will use the beginning of the hot-added range to build
  50  * the page tables for the memmap array that describes the entire range.
  51  * Only selected architectures support it with SPARSE_VMEMMAP.
  52  * This is only a hint, the core kernel can decide to not do this based on
  53  * different alignment checks.
  54  */
  55 #define MHP_MEMMAP_ON_MEMORY   ((__force mhp_t)BIT(1))
  56 /*
  57  * The nid field specifies a memory group id (mgid) instead. The memory group
  58  * implies the node id (nid).
  59  */
  60 #define MHP_NID_IS_MGID         ((__force mhp_t)BIT(2))
  61 /*
  62  * The hotplugged memory is completely inaccessible while the memory is
  63  * offline. The memory provider will handle MEM_PREPARE_ONLINE /
  64  * MEM_FINISH_OFFLINE notifications and make the memory accessible.
  65  *
  66  * This flag is only relevant when used along with MHP_MEMMAP_ON_MEMORY,
  67  * because the altmap cannot be written (e.g., poisoned) when adding
  68  * memory -- before it is set online.
  69  *
  70  * This allows for adding memory with an altmap that is not currently
  71  * made available by a hypervisor. When onlining that memory, the
  72  * hypervisor can be instructed to make that memory available, and
  73  * the onlining phase will not require any memory allocations, which is
  74  * helpful in low-memory situations.
  75  */
  76 #define MHP_OFFLINE_INACCESSIBLE        ((__force mhp_t)BIT(3))
  77
  78 /*
  79  * Extended parameters for memory hotplug:
  80  * altmap: alternative allocator for memmap array (optional)
  81  * pgprot: page protection flags to apply to newly created page tables
  82  *      (required)
  83  */
  84 struct mhp_params {
  85         struct vmem_altmap *altmap;
  86         pgprot_t pgprot;
  87         struct dev_pagemap *pgmap;
  88 };
  89
  90 bool mhp_range_allowed(u64 start, u64 size, bool need_mapping);
  91 struct range mhp_get_pluggable_range(bool need_mapping);
  92 bool mhp_supports_memmap_on_memory(void);
  93
  94 /*
  95  * Zone resizing functions
  96  *
  97  * Note: any attempt to resize a zone should has pgdat_resize_lock()
  98  * zone_span_writelock() both held. This ensure the size of a zone
  99  * can't be changed while pgdat_resize_lock() held.
 100  */
 101 static inline unsigned zone_span_seqbegin(struct zone *zone)
 102 {
 103         return read_seqbegin(&zone->span_seqlock);
 104 }
 105 static inline int zone_span_seqretry(struct zone *zone, unsigned iv)
 106 {
 107         return read_seqretry(&zone->span_seqlock, iv);
 108 }
 109 static inline void zone_span_writelock(struct zone *zone)
 110 {
 111         write_seqlock(&zone->span_seqlock);
 112 }
 113 static inline void zone_span_writeunlock(struct zone *zone)
 114 {
 115         write_sequnlock(&zone->span_seqlock);
 116 }
 117 static inline void zone_seqlock_init(struct zone *zone)
 118 {
 119         seqlock_init(&zone->span_seqlock);
 120 }
 121 extern void adjust_present_page_count(struct page *page,
 122                                       struct memory_group *group,
 123                                       long nr_pages);
 124 /* VM interface that may be used by firmware interface */
 125 extern int mhp_init_memmap_on_memory(unsigned long pfn, unsigned long nr_pages,
 126                                      struct zone *zone, bool mhp_off_inaccessible);
 127 extern void mhp_deinit_memmap_on_memory(unsigned long pfn, unsigned long nr_pages);
 128 extern int online_pages(unsigned long pfn, unsigned long nr_pages,
 129                         struct zone *zone, struct memory_group *group);
 130 extern unsigned long __offline_isolated_pages(unsigned long start_pfn,
 131                 unsigned long end_pfn);
 132
 133 typedef void (*online_page_callback_t)(struct page *page, unsigned int order);
 134
 135 extern void generic_online_page(struct page *page, unsigned int order);
 136 extern int set_online_page_callback(online_page_callback_t callback);
 137 extern int restore_online_page_callback(online_page_callback_t callback);
 138
 139 extern int try_online_node(int nid);
 140
 141 extern int arch_add_memory(int nid, u64 start, u64 size,
 142                            struct mhp_params *params);
 143 extern u64 max_mem_size;
 144
 145 extern int mhp_online_type_from_str(const char *str);
 146
 147 /* If movable_node boot option specified */
 148 extern bool movable_node_enabled;
 149 static inline bool movable_node_is_enabled(void)
 150 {
 151         return movable_node_enabled;
 152 }
 153
 154 extern void arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap);
 155 extern void __remove_pages(unsigned long start_pfn, unsigned long nr_pages,
 156                            struct vmem_altmap *altmap);
 157
 158 /* reasonably generic interface to expand the physical pages */
 159 extern int __add_pages(int nid, unsigned long start_pfn, unsigned long nr_pages,
 160                        struct mhp_params *params);
 161
 162 #ifndef CONFIG_ARCH_HAS_ADD_PAGES
 163 static inline int add_pages(int nid, unsigned long start_pfn,
 164                 unsigned long nr_pages, struct mhp_params *params)
 165 {
 166         return __add_pages(nid, start_pfn, nr_pages, params);
 167 }
 168 #else /* ARCH_HAS_ADD_PAGES */
 169 int add_pages(int nid, unsigned long start_pfn, unsigned long nr_pages,
 170               struct mhp_params *params);
 171 #endif /* ARCH_HAS_ADD_PAGES */
 172
 173 void get_online_mems(void);
 174 void put_online_mems(void);
 175
 176 void mem_hotplug_begin(void);
 177 void mem_hotplug_done(void);
 178
 179 /* See kswapd_is_running() */
 180 static inline void pgdat_kswapd_lock(pg_data_t *pgdat)
 181 {
 182         mutex_lock(&pgdat->kswapd_lock);
 183 }
 184
 185 static inline void pgdat_kswapd_unlock(pg_data_t *pgdat)
 186 {
 187         mutex_unlock(&pgdat->kswapd_lock);
 188 }
 189
 190 static inline void pgdat_kswapd_lock_init(pg_data_t *pgdat)
 191 {
 192         mutex_init(&pgdat->kswapd_lock);
 193 }
 194
 195 #else /* ! CONFIG_MEMORY_HOTPLUG */
 196 #define pfn_to_online_page(pfn)                 \
 197 ({                                              \
 198         struct page *___page = NULL;            \
 199         if (pfn_valid(pfn))                     \
 200                 ___page = pfn_to_page(pfn);     \
 201         ___page;                                \
 202  })
 203
 204 static inline unsigned zone_span_seqbegin(struct zone *zone)
 205 {
 206         return 0;
 207 }
 208 static inline int zone_span_seqretry(struct zone *zone, unsigned iv)
 209 {
 210         return 0;
 211 }
 212 static inline void zone_span_writelock(struct zone *zone) {}
 213 static inline void zone_span_writeunlock(struct zone *zone) {}
 214 static inline void zone_seqlock_init(struct zone *zone) {}
 215
 216 static inline int try_online_node(int nid)
 217 {
 218         return 0;
 219 }
 220
 221 static inline void get_online_mems(void) {}
 222 static inline void put_online_mems(void) {}
 223
 224 static inline void mem_hotplug_begin(void) {}
 225 static inline void mem_hotplug_done(void) {}
 226
 227 static inline bool movable_node_is_enabled(void)
 228 {
 229         return false;
 230 }
 231
 232 static inline bool mhp_supports_memmap_on_memory(void)
 233 {
 234         return false;
 235 }
 236
 237 static inline void pgdat_kswapd_lock(pg_data_t *pgdat) {}
 238 static inline void pgdat_kswapd_unlock(pg_data_t *pgdat) {}
 239 static inline void pgdat_kswapd_lock_init(pg_data_t *pgdat) {}
 240 #endif /* ! CONFIG_MEMORY_HOTPLUG */
 241
 242 /*
 243  * Keep this declaration outside CONFIG_MEMORY_HOTPLUG as some
 244  * platforms might override and use arch_get_mappable_range()
 245  * for internal non memory hotplug purposes.
 246  */
 247 struct range arch_get_mappable_range(void);
 248
 249 #if defined(CONFIG_MEMORY_HOTPLUG) || defined(CONFIG_DEFERRED_STRUCT_PAGE_INIT)
 250 /*
 251  * pgdat resizing functions
 252  */
 253 static inline
 254 void pgdat_resize_lock(struct pglist_data *pgdat, unsigned long *flags)
 255 {
 256         spin_lock_irqsave(&pgdat->node_size_lock, *flags);
 257 }
 258 static inline
 259 void pgdat_resize_unlock(struct pglist_data *pgdat, unsigned long *flags)
 260 {
 261         spin_unlock_irqrestore(&pgdat->node_size_lock, *flags);
 262 }
 263 static inline
 264 void pgdat_resize_init(struct pglist_data *pgdat)
 265 {
 266         spin_lock_init(&pgdat->node_size_lock);
 267 }
 268 #else /* !(CONFIG_MEMORY_HOTPLUG || CONFIG_DEFERRED_STRUCT_PAGE_INIT) */
 269 /*
 270  * Stub functions for when hotplug is off
 271  */
 272 static inline void pgdat_resize_lock(struct pglist_data *p, unsigned long *f) {}
 273 static inline void pgdat_resize_unlock(struct pglist_data *p, unsigned long *f) {}
 274 static inline void pgdat_resize_init(struct pglist_data *pgdat) {}
 275 #endif /* !(CONFIG_MEMORY_HOTPLUG || CONFIG_DEFERRED_STRUCT_PAGE_INIT) */
 276
 277 #ifdef CONFIG_MEMORY_HOTREMOVE
 278
 279 extern void try_offline_node(int nid);
 280 extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages,
 281                          struct zone *zone, struct memory_group *group);
 282 extern int remove_memory(u64 start, u64 size);
 283 extern void __remove_memory(u64 start, u64 size);
 284 extern int offline_and_remove_memory(u64 start, u64 size);
 285
 286 #else
 287 static inline void try_offline_node(int nid) {}
 288
 289 static inline int offline_pages(unsigned long start_pfn, unsigned long nr_pages,
 290                                 struct zone *zone, struct memory_group *group)
 291 {
 292         return -EINVAL;
 293 }
 294
 295 static inline int remove_memory(u64 start, u64 size)
 296 {
 297         return -EBUSY;
 298 }
 299
 300 static inline void __remove_memory(u64 start, u64 size) {}
 301 #endif /* CONFIG_MEMORY_HOTREMOVE */
 302
 303 #ifdef CONFIG_MEMORY_HOTPLUG
 304 /* Default online_type (MMOP_*) when new memory blocks are added. */
 305 extern int mhp_get_default_online_type(void);
 306 extern void mhp_set_default_online_type(int online_type);
 307 extern void __ref free_area_init_core_hotplug(struct pglist_data *pgdat);
 308 extern int __add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags);
 309 extern int add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags);
 310 extern int add_memory_resource(int nid, struct resource *resource,
 311                                mhp_t mhp_flags);
 312 extern int add_memory_driver_managed(int nid, u64 start, u64 size,
 313                                      const char *resource_name,
 314                                      mhp_t mhp_flags);
 315 extern void move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn,
 316                                    unsigned long nr_pages,
 317                                    struct vmem_altmap *altmap, int migratetype);
 318 extern void remove_pfn_range_from_zone(struct zone *zone,
 319                                        unsigned long start_pfn,
 320                                        unsigned long nr_pages);
 321 extern int sparse_add_section(int nid, unsigned long pfn,
 322                 unsigned long nr_pages, struct vmem_altmap *altmap,
 323                 struct dev_pagemap *pgmap);
 324 extern void sparse_remove_section(unsigned long pfn, unsigned long nr_pages,
 325                                   struct vmem_altmap *altmap);
 326 extern struct page *sparse_decode_mem_map(unsigned long coded_mem_map,
 327                                           unsigned long pnum);
 328 extern struct zone *zone_for_pfn_range(int online_type, int nid,
 329                 struct memory_group *group, unsigned long start_pfn,
 330                 unsigned long nr_pages);
 331 extern int arch_create_linear_mapping(int nid, u64 start, u64 size,
 332                                       struct mhp_params *params);
 333 void arch_remove_linear_mapping(u64 start, u64 size);
 334 #endif /* CONFIG_MEMORY_HOTPLUG */
 335
 336 #endif /* __LINUX_MEMORY_HOTPLUG_H */