1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_SWAP_H 3 #define _LINUX_SWAP_H 4 5 #include <linux/spinlock.h> 6 #include <linux/linkage.h> 7 #include <linux/mmzone.h> 8 #include <linux/list.h> 9 #include <linux/memcontrol.h> 10 #include <linux/sched.h> 11 #include <linux/node.h> 12 #include <linux/fs.h> 13 #include <linux/pagemap.h> 14 #include <linux/atomic.h> 15 #include <linux/page-flags.h> 16 #include <uapi/linux/mempolicy.h> 17 #include <asm/page.h> 18 19 struct notifier_block; 20 21 struct bio; 22 23 struct pagevec; 24 25 #define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */ 26 #define SWAP_FLAG_PRIO_MASK 0x7fff 27 #define SWAP_FLAG_PRIO_SHIFT 0 28 #define SWAP_FLAG_DISCARD 0x10000 /* enable discard for swap */ 29 #define SWAP_FLAG_DISCARD_ONCE 0x20000 /* discard swap area at swapon-time */ 30 #define SWAP_FLAG_DISCARD_PAGES 0x40000 /* discard page-clusters after use */ 31 32 #define SWAP_FLAGS_VALID (SWAP_FLAG_PRIO_MASK | SWAP_FLAG_PREFER | \ 33 SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE | \ 34 SWAP_FLAG_DISCARD_PAGES) 35 #define SWAP_BATCH 64 36 37 static inline int current_is_kswapd(void) 38 { 39 return current->flags & PF_KSWAPD; 40 } 41 42 /* 43 * MAX_SWAPFILES defines the maximum number of swaptypes: things which can 44 * be swapped to. The swap type and the offset into that swap type are 45 * encoded into pte's and into pgoff_t's in the swapcache. Using five bits 46 * for the type means that the maximum number of swapcache pages is 27 bits 47 * on 32-bit-pgoff_t architectures. And that assumes that the architecture packs 48 * the type/offset into the pte as 5/27 as well. 49 */ 50 #define MAX_SWAPFILES_SHIFT 5 51 52 /* 53 * Use some of the swap files numbers for other purposes. This 54 * is a convenient way to hook into the VM to trigger special 55 * actions on faults. 56 */ 57 58 /* 59 * Unaddressable device memory support. See include/linux/hmm.h and 60 * Documentation/vm/hmm.rst. Short description is we need struct pages for 61 * device memory that is unaddressable (inaccessible) by CPU, so that we can 62 * migrate part of a process memory to device memory. 63 * 64 * When a page is migrated from CPU to device, we set the CPU page table entry 65 * to a special SWP_DEVICE_{READ|WRITE} entry. 66 * 67 * When a page is mapped by the device for exclusive access we set the CPU page 68 * table entries to special SWP_DEVICE_EXCLUSIVE_* entries. 69 */ 70 #ifdef CONFIG_DEVICE_PRIVATE 71 #define SWP_DEVICE_NUM 4 72 #define SWP_DEVICE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM) 73 #define SWP_DEVICE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+1) 74 #define SWP_DEVICE_EXCLUSIVE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+2) 75 #define SWP_DEVICE_EXCLUSIVE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+3) 76 #else 77 #define SWP_DEVICE_NUM 0 78 #endif 79 80 /* 81 * NUMA node memory migration support 82 */ 83 #ifdef CONFIG_MIGRATION 84 #define SWP_MIGRATION_NUM 2 85 #define SWP_MIGRATION_READ (MAX_SWAPFILES + SWP_HWPOISON_NUM) 86 #define SWP_MIGRATION_WRITE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1) 87 #else 88 #define SWP_MIGRATION_NUM 0 89 #endif 90 91 /* 92 * Handling of hardware poisoned pages with memory corruption. 93 */ 94 #ifdef CONFIG_MEMORY_FAILURE 95 #define SWP_HWPOISON_NUM 1 96 #define SWP_HWPOISON MAX_SWAPFILES 97 #else 98 #define SWP_HWPOISON_NUM 0 99 #endif 100 101 #define MAX_SWAPFILES \ 102 ((1 << MAX_SWAPFILES_SHIFT) - SWP_DEVICE_NUM - \ 103 SWP_MIGRATION_NUM - SWP_HWPOISON_NUM) 104 105 /* 106 * Magic header for a swap area. The first part of the union is 107 * what the swap magic looks like for the old (limited to 128MB) 108 * swap area format, the second part of the union adds - in the 109 * old reserved area - some extra information. Note that the first 110 * kilobyte is reserved for boot loader or disk label stuff... 111 * 112 * Having the magic at the end of the PAGE_SIZE makes detecting swap 113 * areas somewhat tricky on machines that support multiple page sizes. 114 * For 2.5 we'll probably want to move the magic to just beyond the 115 * bootbits... 116 */ 117 union swap_header { 118 struct { 119 char reserved[PAGE_SIZE - 10]; 120 char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */ 121 } magic; 122 struct { 123 char bootbits[1024]; /* Space for disklabel etc. */ 124 __u32 version; 125 __u32 last_page; 126 __u32 nr_badpages; 127 unsigned char sws_uuid[16]; 128 unsigned char sws_volume[16]; 129 __u32 padding[117]; 130 __u32 badpages[1]; 131 } info; 132 }; 133 134 /* 135 * current->reclaim_state points to one of these when a task is running 136 * memory reclaim 137 */ 138 struct reclaim_state { 139 unsigned long reclaimed_slab; 140 }; 141 142 #ifdef __KERNEL__ 143 144 struct address_space; 145 struct sysinfo; 146 struct writeback_control; 147 struct zone; 148 149 /* 150 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of 151 * disk blocks. A list of swap extents maps the entire swapfile. (Where the 152 * term `swapfile' refers to either a blockdevice or an IS_REG file. Apart 153 * from setup, they're handled identically. 154 * 155 * We always assume that blocks are of size PAGE_SIZE. 156 */ 157 struct swap_extent { 158 struct rb_node rb_node; 159 pgoff_t start_page; 160 pgoff_t nr_pages; 161 sector_t start_block; 162 }; 163 164 /* 165 * Max bad pages in the new format.. 166 */ 167 #define MAX_SWAP_BADPAGES \ 168 ((offsetof(union swap_header, magic.magic) - \ 169 offsetof(union swap_header, info.badpages)) / sizeof(int)) 170 171 enum { 172 SWP_USED = (1 << 0), /* is slot in swap_info[] used? */ 173 SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */ 174 SWP_DISCARDABLE = (1 << 2), /* blkdev support discard */ 175 SWP_DISCARDING = (1 << 3), /* now discarding a free cluster */ 176 SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */ 177 SWP_CONTINUED = (1 << 5), /* swap_map has count continuation */ 178 SWP_BLKDEV = (1 << 6), /* its a block device */ 179 SWP_ACTIVATED = (1 << 7), /* set after swap_activate success */ 180 SWP_FS_OPS = (1 << 8), /* swapfile operations go through fs */ 181 SWP_AREA_DISCARD = (1 << 9), /* single-time swap area discards */ 182 SWP_PAGE_DISCARD = (1 << 10), /* freed swap page-cluster discards */ 183 SWP_STABLE_WRITES = (1 << 11), /* no overwrite PG_writeback pages */ 184 SWP_SYNCHRONOUS_IO = (1 << 12), /* synchronous IO is efficient */ 185 /* add others here before... */ 186 SWP_SCANNING = (1 << 14), /* refcount in scan_swap_map */ 187 }; 188 189 #define SWAP_CLUSTER_MAX 32UL 190 #define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX 191 192 /* Bit flag in swap_map */ 193 #define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */ 194 #define COUNT_CONTINUED 0x80 /* Flag swap_map continuation for full count */ 195 196 /* Special value in first swap_map */ 197 #define SWAP_MAP_MAX 0x3e /* Max count */ 198 #define SWAP_MAP_BAD 0x3f /* Note page is bad */ 199 #define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs */ 200 201 /* Special value in each swap_map continuation */ 202 #define SWAP_CONT_MAX 0x7f /* Max count */ 203 204 /* 205 * We use this to track usage of a cluster. A cluster is a block of swap disk 206 * space with SWAPFILE_CLUSTER pages long and naturally aligns in disk. All 207 * free clusters are organized into a list. We fetch an entry from the list to 208 * get a free cluster. 209 * 210 * The data field stores next cluster if the cluster is free or cluster usage 211 * counter otherwise. The flags field determines if a cluster is free. This is 212 * protected by swap_info_struct.lock. 213 */ 214 struct swap_cluster_info { 215 spinlock_t lock; /* 216 * Protect swap_cluster_info fields 217 * and swap_info_struct->swap_map 218 * elements correspond to the swap 219 * cluster 220 */ 221 unsigned int data:24; 222 unsigned int flags:8; 223 }; 224 #define CLUSTER_FLAG_FREE 1 /* This cluster is free */ 225 #define CLUSTER_FLAG_NEXT_NULL 2 /* This cluster has no next cluster */ 226 #define CLUSTER_FLAG_HUGE 4 /* This cluster is backing a transparent huge page */ 227 228 /* 229 * We assign a cluster to each CPU, so each CPU can allocate swap entry from 230 * its own cluster and swapout sequentially. The purpose is to optimize swapout 231 * throughput. 232 */ 233 struct percpu_cluster { 234 struct swap_cluster_info index; /* Current cluster index */ 235 unsigned int next; /* Likely next allocation offset */ 236 }; 237 238 struct swap_cluster_list { 239 struct swap_cluster_info head; 240 struct swap_cluster_info tail; 241 }; 242 243 /* 244 * The in-memory structure used to track swap areas. 245 */ 246 struct swap_info_struct { 247 struct percpu_ref users; /* indicate and keep swap device valid. */ 248 unsigned long flags; /* SWP_USED etc: see above */ 249 signed short prio; /* swap priority of this type */ 250 struct plist_node list; /* entry in swap_active_head */ 251 signed char type; /* strange name for an index */ 252 unsigned int max; /* extent of the swap_map */ 253 unsigned char *swap_map; /* vmalloc'ed array of usage counts */ 254 struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */ 255 struct swap_cluster_list free_clusters; /* free clusters list */ 256 unsigned int lowest_bit; /* index of first free in swap_map */ 257 unsigned int highest_bit; /* index of last free in swap_map */ 258 unsigned int pages; /* total of usable pages of swap */ 259 unsigned int inuse_pages; /* number of those currently in use */ 260 unsigned int cluster_next; /* likely index for next allocation */ 261 unsigned int cluster_nr; /* countdown to next cluster search */ 262 unsigned int __percpu *cluster_next_cpu; /*percpu index for next allocation */ 263 struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */ 264 struct rb_root swap_extent_root;/* root of the swap extent rbtree */ 265 struct block_device *bdev; /* swap device or bdev of swap file */ 266 struct file *swap_file; /* seldom referenced */ 267 unsigned int old_block_size; /* seldom referenced */ 268 struct completion comp; /* seldom referenced */ 269 #ifdef CONFIG_FRONTSWAP 270 unsigned long *frontswap_map; /* frontswap in-use, one bit per page */ 271 atomic_t frontswap_pages; /* frontswap pages in-use counter */ 272 #endif 273 spinlock_t lock; /* 274 * protect map scan related fields like 275 * swap_map, lowest_bit, highest_bit, 276 * inuse_pages, cluster_next, 277 * cluster_nr, lowest_alloc, 278 * highest_alloc, free/discard cluster 279 * list. other fields are only changed 280 * at swapon/swapoff, so are protected 281 * by swap_lock. changing flags need 282 * hold this lock and swap_lock. If 283 * both locks need hold, hold swap_lock 284 * first. 285 */ 286 spinlock_t cont_lock; /* 287 * protect swap count continuation page 288 * list. 289 */ 290 struct work_struct discard_work; /* discard worker */ 291 struct swap_cluster_list discard_clusters; /* discard clusters list */ 292 struct plist_node avail_lists[]; /* 293 * entries in swap_avail_heads, one 294 * entry per node. 295 * Must be last as the number of the 296 * array is nr_node_ids, which is not 297 * a fixed value so have to allocate 298 * dynamically. 299 * And it has to be an array so that 300 * plist_for_each_* can work. 301 */ 302 }; 303 304 #ifdef CONFIG_64BIT 305 #define SWAP_RA_ORDER_CEILING 5 306 #else 307 /* Avoid stack overflow, because we need to save part of page table */ 308 #define SWAP_RA_ORDER_CEILING 3 309 #define SWAP_RA_PTE_CACHE_SIZE (1 << SWAP_RA_ORDER_CEILING) 310 #endif 311 312 struct vma_swap_readahead { 313 unsigned short win; 314 unsigned short offset; 315 unsigned short nr_pte; 316 #ifdef CONFIG_64BIT 317 pte_t *ptes; 318 #else 319 pte_t ptes[SWAP_RA_PTE_CACHE_SIZE]; 320 #endif 321 }; 322 323 static inline swp_entry_t folio_swap_entry(struct folio *folio) 324 { 325 swp_entry_t entry = { .val = page_private(&folio->page) }; 326 return entry; 327 } 328 329 /* linux/mm/workingset.c */ 330 void workingset_age_nonresident(struct lruvec *lruvec, unsigned long nr_pages); 331 void *workingset_eviction(struct page *page, struct mem_cgroup *target_memcg); 332 void workingset_refault(struct folio *folio, void *shadow); 333 void workingset_activation(struct folio *folio); 334 335 /* Only track the nodes of mappings with shadow entries */ 336 void workingset_update_node(struct xa_node *node); 337 #define mapping_set_update(xas, mapping) do { \ 338 if (!dax_mapping(mapping) && !shmem_mapping(mapping)) \ 339 xas_set_update(xas, workingset_update_node); \ 340 } while (0) 341 342 /* linux/mm/page_alloc.c */ 343 extern unsigned long totalreserve_pages; 344 345 /* Definition of global_zone_page_state not available yet */ 346 #define nr_free_pages() global_zone_page_state(NR_FREE_PAGES) 347 348 349 /* linux/mm/swap.c */ 350 extern void lru_note_cost(struct lruvec *lruvec, bool file, 351 unsigned int nr_pages); 352 extern void lru_note_cost_folio(struct folio *); 353 extern void folio_add_lru(struct folio *); 354 extern void lru_cache_add(struct page *); 355 void mark_page_accessed(struct page *); 356 void folio_mark_accessed(struct folio *); 357 358 extern atomic_t lru_disable_count; 359 360 static inline bool lru_cache_disabled(void) 361 { 362 return atomic_read(&lru_disable_count); 363 } 364 365 static inline void lru_cache_enable(void) 366 { 367 atomic_dec(&lru_disable_count); 368 } 369 370 extern void lru_cache_disable(void); 371 extern void lru_add_drain(void); 372 extern void lru_add_drain_cpu(int cpu); 373 extern void lru_add_drain_cpu_zone(struct zone *zone); 374 extern void lru_add_drain_all(void); 375 extern void deactivate_file_page(struct page *page); 376 extern void deactivate_page(struct page *page); 377 extern void mark_page_lazyfree(struct page *page); 378 extern void swap_setup(void); 379 380 extern void lru_cache_add_inactive_or_unevictable(struct page *page, 381 struct vm_area_struct *vma); 382 383 /* linux/mm/vmscan.c */ 384 extern unsigned long zone_reclaimable_pages(struct zone *zone); 385 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order, 386 gfp_t gfp_mask, nodemask_t *mask); 387 extern bool __isolate_lru_page_prepare(struct page *page, isolate_mode_t mode); 388 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg, 389 unsigned long nr_pages, 390 gfp_t gfp_mask, 391 bool may_swap); 392 extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem, 393 gfp_t gfp_mask, bool noswap, 394 pg_data_t *pgdat, 395 unsigned long *nr_scanned); 396 extern unsigned long shrink_all_memory(unsigned long nr_pages); 397 extern int vm_swappiness; 398 extern int remove_mapping(struct address_space *mapping, struct page *page); 399 400 extern unsigned long reclaim_pages(struct list_head *page_list); 401 #ifdef CONFIG_NUMA 402 extern int node_reclaim_mode; 403 extern int sysctl_min_unmapped_ratio; 404 extern int sysctl_min_slab_ratio; 405 #else 406 #define node_reclaim_mode 0 407 #endif 408 409 static inline bool node_reclaim_enabled(void) 410 { 411 /* Is any node_reclaim_mode bit set? */ 412 return node_reclaim_mode & (RECLAIM_ZONE|RECLAIM_WRITE|RECLAIM_UNMAP); 413 } 414 415 extern void check_move_unevictable_pages(struct pagevec *pvec); 416 417 extern void kswapd_run(int nid); 418 extern void kswapd_stop(int nid); 419 420 #ifdef CONFIG_SWAP 421 422 #include <linux/blk_types.h> /* for bio_end_io_t */ 423 424 /* linux/mm/page_io.c */ 425 extern int swap_readpage(struct page *page, bool do_poll); 426 extern int swap_writepage(struct page *page, struct writeback_control *wbc); 427 extern void end_swap_bio_write(struct bio *bio); 428 extern int __swap_writepage(struct page *page, struct writeback_control *wbc, 429 bio_end_io_t end_write_func); 430 extern int swap_set_page_dirty(struct page *page); 431 432 int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, 433 unsigned long nr_pages, sector_t start_block); 434 int generic_swapfile_activate(struct swap_info_struct *, struct file *, 435 sector_t *); 436 437 /* linux/mm/swap_state.c */ 438 /* One swap address space for each 64M swap space */ 439 #define SWAP_ADDRESS_SPACE_SHIFT 14 440 #define SWAP_ADDRESS_SPACE_PAGES (1 << SWAP_ADDRESS_SPACE_SHIFT) 441 extern struct address_space *swapper_spaces[]; 442 #define swap_address_space(entry) \ 443 (&swapper_spaces[swp_type(entry)][swp_offset(entry) \ 444 >> SWAP_ADDRESS_SPACE_SHIFT]) 445 static inline unsigned long total_swapcache_pages(void) 446 { 447 return global_node_page_state(NR_SWAPCACHE); 448 } 449 450 extern void show_swap_cache_info(void); 451 extern int add_to_swap(struct page *page); 452 extern void *get_shadow_from_swap_cache(swp_entry_t entry); 453 extern int add_to_swap_cache(struct page *page, swp_entry_t entry, 454 gfp_t gfp, void **shadowp); 455 extern void __delete_from_swap_cache(struct page *page, 456 swp_entry_t entry, void *shadow); 457 extern void delete_from_swap_cache(struct page *); 458 extern void clear_shadow_from_swap_cache(int type, unsigned long begin, 459 unsigned long end); 460 extern void free_swap_cache(struct page *); 461 extern void free_page_and_swap_cache(struct page *); 462 extern void free_pages_and_swap_cache(struct page **, int); 463 extern struct page *lookup_swap_cache(swp_entry_t entry, 464 struct vm_area_struct *vma, 465 unsigned long addr); 466 struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index); 467 extern struct page *read_swap_cache_async(swp_entry_t, gfp_t, 468 struct vm_area_struct *vma, unsigned long addr, 469 bool do_poll); 470 extern struct page *__read_swap_cache_async(swp_entry_t, gfp_t, 471 struct vm_area_struct *vma, unsigned long addr, 472 bool *new_page_allocated); 473 extern struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t flag, 474 struct vm_fault *vmf); 475 extern struct page *swapin_readahead(swp_entry_t entry, gfp_t flag, 476 struct vm_fault *vmf); 477 478 /* linux/mm/swapfile.c */ 479 extern atomic_long_t nr_swap_pages; 480 extern long total_swap_pages; 481 extern atomic_t nr_rotate_swap; 482 extern bool has_usable_swap(void); 483 484 /* Swap 50% full? Release swapcache more aggressively.. */ 485 static inline bool vm_swap_full(void) 486 { 487 return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages; 488 } 489 490 static inline long get_nr_swap_pages(void) 491 { 492 return atomic_long_read(&nr_swap_pages); 493 } 494 495 extern void si_swapinfo(struct sysinfo *); 496 extern swp_entry_t get_swap_page(struct page *page); 497 extern void put_swap_page(struct page *page, swp_entry_t entry); 498 extern swp_entry_t get_swap_page_of_type(int); 499 extern int get_swap_pages(int n, swp_entry_t swp_entries[], int entry_size); 500 extern int add_swap_count_continuation(swp_entry_t, gfp_t); 501 extern void swap_shmem_alloc(swp_entry_t); 502 extern int swap_duplicate(swp_entry_t); 503 extern int swapcache_prepare(swp_entry_t); 504 extern void swap_free(swp_entry_t); 505 extern void swapcache_free_entries(swp_entry_t *entries, int n); 506 extern int free_swap_and_cache(swp_entry_t); 507 int swap_type_of(dev_t device, sector_t offset); 508 int find_first_swap(dev_t *device); 509 extern unsigned int count_swap_pages(int, int); 510 extern sector_t swapdev_block(int, pgoff_t); 511 extern int page_swapcount(struct page *); 512 extern int __swap_count(swp_entry_t entry); 513 extern int __swp_swapcount(swp_entry_t entry); 514 extern int swp_swapcount(swp_entry_t entry); 515 extern struct swap_info_struct *page_swap_info(struct page *); 516 extern struct swap_info_struct *swp_swap_info(swp_entry_t entry); 517 extern bool reuse_swap_page(struct page *, int *); 518 extern int try_to_free_swap(struct page *); 519 struct backing_dev_info; 520 extern int init_swap_address_space(unsigned int type, unsigned long nr_pages); 521 extern void exit_swap_address_space(unsigned int type); 522 extern struct swap_info_struct *get_swap_device(swp_entry_t entry); 523 sector_t swap_page_sector(struct page *page); 524 525 static inline void put_swap_device(struct swap_info_struct *si) 526 { 527 percpu_ref_put(&si->users); 528 } 529 530 #else /* CONFIG_SWAP */ 531 532 static inline int swap_readpage(struct page *page, bool do_poll) 533 { 534 return 0; 535 } 536 537 static inline struct swap_info_struct *swp_swap_info(swp_entry_t entry) 538 { 539 return NULL; 540 } 541 542 static inline struct swap_info_struct *get_swap_device(swp_entry_t entry) 543 { 544 return NULL; 545 } 546 547 static inline void put_swap_device(struct swap_info_struct *si) 548 { 549 } 550 551 static inline struct address_space *swap_address_space(swp_entry_t entry) 552 { 553 return NULL; 554 } 555 556 #define get_nr_swap_pages() 0L 557 #define total_swap_pages 0L 558 #define total_swapcache_pages() 0UL 559 #define vm_swap_full() 0 560 561 #define si_swapinfo(val) \ 562 do { (val)->freeswap = (val)->totalswap = 0; } while (0) 563 /* only sparc can not include linux/pagemap.h in this file 564 * so leave put_page and release_pages undeclared... */ 565 #define free_page_and_swap_cache(page) \ 566 put_page(page) 567 #define free_pages_and_swap_cache(pages, nr) \ 568 release_pages((pages), (nr)); 569 570 static inline void free_swap_cache(struct page *page) 571 { 572 } 573 574 static inline void show_swap_cache_info(void) 575 { 576 } 577 578 /* used to sanity check ptes in zap_pte_range when CONFIG_SWAP=0 */ 579 #define free_swap_and_cache(e) is_pfn_swap_entry(e) 580 581 static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask) 582 { 583 return 0; 584 } 585 586 static inline void swap_shmem_alloc(swp_entry_t swp) 587 { 588 } 589 590 static inline int swap_duplicate(swp_entry_t swp) 591 { 592 return 0; 593 } 594 595 static inline void swap_free(swp_entry_t swp) 596 { 597 } 598 599 static inline void put_swap_page(struct page *page, swp_entry_t swp) 600 { 601 } 602 603 static inline struct page *swap_cluster_readahead(swp_entry_t entry, 604 gfp_t gfp_mask, struct vm_fault *vmf) 605 { 606 return NULL; 607 } 608 609 static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask, 610 struct vm_fault *vmf) 611 { 612 return NULL; 613 } 614 615 static inline int swap_writepage(struct page *p, struct writeback_control *wbc) 616 { 617 return 0; 618 } 619 620 static inline struct page *lookup_swap_cache(swp_entry_t swp, 621 struct vm_area_struct *vma, 622 unsigned long addr) 623 { 624 return NULL; 625 } 626 627 static inline 628 struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index) 629 { 630 return find_get_page(mapping, index); 631 } 632 633 static inline int add_to_swap(struct page *page) 634 { 635 return 0; 636 } 637 638 static inline void *get_shadow_from_swap_cache(swp_entry_t entry) 639 { 640 return NULL; 641 } 642 643 static inline int add_to_swap_cache(struct page *page, swp_entry_t entry, 644 gfp_t gfp_mask, void **shadowp) 645 { 646 return -1; 647 } 648 649 static inline void __delete_from_swap_cache(struct page *page, 650 swp_entry_t entry, void *shadow) 651 { 652 } 653 654 static inline void delete_from_swap_cache(struct page *page) 655 { 656 } 657 658 static inline void clear_shadow_from_swap_cache(int type, unsigned long begin, 659 unsigned long end) 660 { 661 } 662 663 static inline int page_swapcount(struct page *page) 664 { 665 return 0; 666 } 667 668 static inline int __swap_count(swp_entry_t entry) 669 { 670 return 0; 671 } 672 673 static inline int __swp_swapcount(swp_entry_t entry) 674 { 675 return 0; 676 } 677 678 static inline int swp_swapcount(swp_entry_t entry) 679 { 680 return 0; 681 } 682 683 #define reuse_swap_page(page, total_map_swapcount) \ 684 (page_trans_huge_mapcount(page, total_map_swapcount) == 1) 685 686 static inline int try_to_free_swap(struct page *page) 687 { 688 return 0; 689 } 690 691 static inline swp_entry_t get_swap_page(struct page *page) 692 { 693 swp_entry_t entry; 694 entry.val = 0; 695 return entry; 696 } 697 698 #endif /* CONFIG_SWAP */ 699 700 #ifdef CONFIG_THP_SWAP 701 extern int split_swap_cluster(swp_entry_t entry); 702 #else 703 static inline int split_swap_cluster(swp_entry_t entry) 704 { 705 return 0; 706 } 707 #endif 708 709 #ifdef CONFIG_MEMCG 710 static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg) 711 { 712 /* Cgroup2 doesn't have per-cgroup swappiness */ 713 if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) 714 return vm_swappiness; 715 716 /* root ? */ 717 if (mem_cgroup_disabled() || mem_cgroup_is_root(memcg)) 718 return vm_swappiness; 719 720 return memcg->swappiness; 721 } 722 #else 723 static inline int mem_cgroup_swappiness(struct mem_cgroup *mem) 724 { 725 return vm_swappiness; 726 } 727 #endif 728 729 #if defined(CONFIG_SWAP) && defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP) 730 extern void __cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask); 731 static inline void cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask) 732 { 733 if (mem_cgroup_disabled()) 734 return; 735 __cgroup_throttle_swaprate(page, gfp_mask); 736 } 737 #else 738 static inline void cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask) 739 { 740 } 741 #endif 742 743 #ifdef CONFIG_MEMCG_SWAP 744 extern void mem_cgroup_swapout(struct page *page, swp_entry_t entry); 745 extern int __mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry); 746 static inline int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry) 747 { 748 if (mem_cgroup_disabled()) 749 return 0; 750 return __mem_cgroup_try_charge_swap(page, entry); 751 } 752 753 extern void __mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages); 754 static inline void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages) 755 { 756 if (mem_cgroup_disabled()) 757 return; 758 __mem_cgroup_uncharge_swap(entry, nr_pages); 759 } 760 761 extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg); 762 extern bool mem_cgroup_swap_full(struct page *page); 763 #else 764 static inline void mem_cgroup_swapout(struct page *page, swp_entry_t entry) 765 { 766 } 767 768 static inline int mem_cgroup_try_charge_swap(struct page *page, 769 swp_entry_t entry) 770 { 771 return 0; 772 } 773 774 static inline void mem_cgroup_uncharge_swap(swp_entry_t entry, 775 unsigned int nr_pages) 776 { 777 } 778 779 static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg) 780 { 781 return get_nr_swap_pages(); 782 } 783 784 static inline bool mem_cgroup_swap_full(struct page *page) 785 { 786 return vm_swap_full(); 787 } 788 #endif 789 790 #endif /* __KERNEL__*/ 791 #endif /* _LINUX_SWAP_H */ 792