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