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 * PTE markers are used to persist information onto PTEs that otherwise 60 * should be a none pte. As its name "PTE" hints, it should only be 61 * applied to the leaves of pgtables. 62 */ 63 #define SWP_PTE_MARKER_NUM 1 64 #define SWP_PTE_MARKER (MAX_SWAPFILES + SWP_HWPOISON_NUM + \ 65 SWP_MIGRATION_NUM + SWP_DEVICE_NUM) 66 67 /* 68 * Unaddressable device memory support. See include/linux/hmm.h and 69 * Documentation/mm/hmm.rst. Short description is we need struct pages for 70 * device memory that is unaddressable (inaccessible) by CPU, so that we can 71 * migrate part of a process memory to device memory. 72 * 73 * When a page is migrated from CPU to device, we set the CPU page table entry 74 * to a special SWP_DEVICE_{READ|WRITE} entry. 75 * 76 * When a page is mapped by the device for exclusive access we set the CPU page 77 * table entries to special SWP_DEVICE_EXCLUSIVE_* entries. 78 */ 79 #ifdef CONFIG_DEVICE_PRIVATE 80 #define SWP_DEVICE_NUM 4 81 #define SWP_DEVICE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM) 82 #define SWP_DEVICE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+1) 83 #define SWP_DEVICE_EXCLUSIVE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+2) 84 #define SWP_DEVICE_EXCLUSIVE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+3) 85 #else 86 #define SWP_DEVICE_NUM 0 87 #endif 88 89 /* 90 * Page migration support. 91 * 92 * SWP_MIGRATION_READ_EXCLUSIVE is only applicable to anonymous pages and 93 * indicates that the referenced (part of) an anonymous page is exclusive to 94 * a single process. For SWP_MIGRATION_WRITE, that information is implicit: 95 * (part of) an anonymous page that are mapped writable are exclusive to a 96 * single process. 97 */ 98 #ifdef CONFIG_MIGRATION 99 #define SWP_MIGRATION_NUM 3 100 #define SWP_MIGRATION_READ (MAX_SWAPFILES + SWP_HWPOISON_NUM) 101 #define SWP_MIGRATION_READ_EXCLUSIVE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1) 102 #define SWP_MIGRATION_WRITE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 2) 103 #else 104 #define SWP_MIGRATION_NUM 0 105 #endif 106 107 /* 108 * Handling of hardware poisoned pages with memory corruption. 109 */ 110 #ifdef CONFIG_MEMORY_FAILURE 111 #define SWP_HWPOISON_NUM 1 112 #define SWP_HWPOISON MAX_SWAPFILES 113 #else 114 #define SWP_HWPOISON_NUM 0 115 #endif 116 117 #define MAX_SWAPFILES \ 118 ((1 << MAX_SWAPFILES_SHIFT) - SWP_DEVICE_NUM - \ 119 SWP_MIGRATION_NUM - SWP_HWPOISON_NUM - \ 120 SWP_PTE_MARKER_NUM) 121 122 /* 123 * Magic header for a swap area. The first part of the union is 124 * what the swap magic looks like for the old (limited to 128MB) 125 * swap area format, the second part of the union adds - in the 126 * old reserved area - some extra information. Note that the first 127 * kilobyte is reserved for boot loader or disk label stuff... 128 * 129 * Having the magic at the end of the PAGE_SIZE makes detecting swap 130 * areas somewhat tricky on machines that support multiple page sizes. 131 * For 2.5 we'll probably want to move the magic to just beyond the 132 * bootbits... 133 */ 134 union swap_header { 135 struct { 136 char reserved[PAGE_SIZE - 10]; 137 char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */ 138 } magic; 139 struct { 140 char bootbits[1024]; /* Space for disklabel etc. */ 141 __u32 version; 142 __u32 last_page; 143 __u32 nr_badpages; 144 unsigned char sws_uuid[16]; 145 unsigned char sws_volume[16]; 146 __u32 padding[117]; 147 __u32 badpages[1]; 148 } info; 149 }; 150 151 /* 152 * current->reclaim_state points to one of these when a task is running 153 * memory reclaim 154 */ 155 struct reclaim_state { 156 /* pages reclaimed outside of LRU-based reclaim */ 157 unsigned long reclaimed; 158 #ifdef CONFIG_LRU_GEN 159 /* per-thread mm walk data */ 160 struct lru_gen_mm_walk *mm_walk; 161 #endif 162 }; 163 164 /* 165 * mm_account_reclaimed_pages(): account reclaimed pages outside of LRU-based 166 * reclaim 167 * @pages: number of pages reclaimed 168 * 169 * If the current process is undergoing a reclaim operation, increment the 170 * number of reclaimed pages by @pages. 171 */ 172 static inline void mm_account_reclaimed_pages(unsigned long pages) 173 { 174 if (current->reclaim_state) 175 current->reclaim_state->reclaimed += pages; 176 } 177 178 #ifdef __KERNEL__ 179 180 struct address_space; 181 struct sysinfo; 182 struct writeback_control; 183 struct zone; 184 185 /* 186 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of 187 * disk blocks. A rbtree of swap extents maps the entire swapfile (Where the 188 * term `swapfile' refers to either a blockdevice or an IS_REG file). Apart 189 * from setup, they're handled identically. 190 * 191 * We always assume that blocks are of size PAGE_SIZE. 192 */ 193 struct swap_extent { 194 struct rb_node rb_node; 195 pgoff_t start_page; 196 pgoff_t nr_pages; 197 sector_t start_block; 198 }; 199 200 /* 201 * Max bad pages in the new format.. 202 */ 203 #define MAX_SWAP_BADPAGES \ 204 ((offsetof(union swap_header, magic.magic) - \ 205 offsetof(union swap_header, info.badpages)) / sizeof(int)) 206 207 enum { 208 SWP_USED = (1 << 0), /* is slot in swap_info[] used? */ 209 SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */ 210 SWP_DISCARDABLE = (1 << 2), /* blkdev support discard */ 211 SWP_DISCARDING = (1 << 3), /* now discarding a free cluster */ 212 SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */ 213 SWP_CONTINUED = (1 << 5), /* swap_map has count continuation */ 214 SWP_BLKDEV = (1 << 6), /* its a block device */ 215 SWP_ACTIVATED = (1 << 7), /* set after swap_activate success */ 216 SWP_FS_OPS = (1 << 8), /* swapfile operations go through fs */ 217 SWP_AREA_DISCARD = (1 << 9), /* single-time swap area discards */ 218 SWP_PAGE_DISCARD = (1 << 10), /* freed swap page-cluster discards */ 219 SWP_STABLE_WRITES = (1 << 11), /* no overwrite PG_writeback pages */ 220 SWP_SYNCHRONOUS_IO = (1 << 12), /* synchronous IO is efficient */ 221 /* add others here before... */ 222 SWP_SCANNING = (1 << 14), /* refcount in scan_swap_map */ 223 }; 224 225 #define SWAP_CLUSTER_MAX 32UL 226 #define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX 227 228 /* Bit flag in swap_map */ 229 #define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */ 230 #define COUNT_CONTINUED 0x80 /* Flag swap_map continuation for full count */ 231 232 /* Special value in first swap_map */ 233 #define SWAP_MAP_MAX 0x3e /* Max count */ 234 #define SWAP_MAP_BAD 0x3f /* Note page is bad */ 235 #define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs */ 236 237 /* Special value in each swap_map continuation */ 238 #define SWAP_CONT_MAX 0x7f /* Max count */ 239 240 /* 241 * We use this to track usage of a cluster. A cluster is a block of swap disk 242 * space with SWAPFILE_CLUSTER pages long and naturally aligns in disk. All 243 * free clusters are organized into a list. We fetch an entry from the list to 244 * get a free cluster. 245 * 246 * The data field stores next cluster if the cluster is free or cluster usage 247 * counter otherwise. The flags field determines if a cluster is free. This is 248 * protected by swap_info_struct.lock. 249 */ 250 struct swap_cluster_info { 251 spinlock_t lock; /* 252 * Protect swap_cluster_info fields 253 * and swap_info_struct->swap_map 254 * elements correspond to the swap 255 * cluster 256 */ 257 unsigned int data:24; 258 unsigned int flags:8; 259 }; 260 #define CLUSTER_FLAG_FREE 1 /* This cluster is free */ 261 #define CLUSTER_FLAG_NEXT_NULL 2 /* This cluster has no next cluster */ 262 #define CLUSTER_FLAG_HUGE 4 /* This cluster is backing a transparent huge page */ 263 264 /* 265 * We assign a cluster to each CPU, so each CPU can allocate swap entry from 266 * its own cluster and swapout sequentially. The purpose is to optimize swapout 267 * throughput. 268 */ 269 struct percpu_cluster { 270 struct swap_cluster_info index; /* Current cluster index */ 271 unsigned int next; /* Likely next allocation offset */ 272 }; 273 274 struct swap_cluster_list { 275 struct swap_cluster_info head; 276 struct swap_cluster_info tail; 277 }; 278 279 /* 280 * The in-memory structure used to track swap areas. 281 */ 282 struct swap_info_struct { 283 struct percpu_ref users; /* indicate and keep swap device valid. */ 284 unsigned long flags; /* SWP_USED etc: see above */ 285 signed short prio; /* swap priority of this type */ 286 struct plist_node list; /* entry in swap_active_head */ 287 signed char type; /* strange name for an index */ 288 unsigned int max; /* extent of the swap_map */ 289 unsigned char *swap_map; /* vmalloc'ed array of usage counts */ 290 struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */ 291 struct swap_cluster_list free_clusters; /* free clusters list */ 292 unsigned int lowest_bit; /* index of first free in swap_map */ 293 unsigned int highest_bit; /* index of last free in swap_map */ 294 unsigned int pages; /* total of usable pages of swap */ 295 unsigned int inuse_pages; /* number of those currently in use */ 296 unsigned int cluster_next; /* likely index for next allocation */ 297 unsigned int cluster_nr; /* countdown to next cluster search */ 298 unsigned int __percpu *cluster_next_cpu; /*percpu index for next allocation */ 299 struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */ 300 struct rb_root swap_extent_root;/* root of the swap extent rbtree */ 301 struct block_device *bdev; /* swap device or bdev of swap file */ 302 struct file *swap_file; /* seldom referenced */ 303 unsigned int old_block_size; /* seldom referenced */ 304 struct completion comp; /* seldom referenced */ 305 #ifdef CONFIG_FRONTSWAP 306 unsigned long *frontswap_map; /* frontswap in-use, one bit per page */ 307 atomic_t frontswap_pages; /* frontswap pages in-use counter */ 308 #endif 309 spinlock_t lock; /* 310 * protect map scan related fields like 311 * swap_map, lowest_bit, highest_bit, 312 * inuse_pages, cluster_next, 313 * cluster_nr, lowest_alloc, 314 * highest_alloc, free/discard cluster 315 * list. other fields are only changed 316 * at swapon/swapoff, so are protected 317 * by swap_lock. changing flags need 318 * hold this lock and swap_lock. If 319 * both locks need hold, hold swap_lock 320 * first. 321 */ 322 spinlock_t cont_lock; /* 323 * protect swap count continuation page 324 * list. 325 */ 326 struct work_struct discard_work; /* discard worker */ 327 struct swap_cluster_list discard_clusters; /* discard clusters list */ 328 struct plist_node avail_lists[]; /* 329 * entries in swap_avail_heads, one 330 * entry per node. 331 * Must be last as the number of the 332 * array is nr_node_ids, which is not 333 * a fixed value so have to allocate 334 * dynamically. 335 * And it has to be an array so that 336 * plist_for_each_* can work. 337 */ 338 }; 339 340 #ifdef CONFIG_64BIT 341 #define SWAP_RA_ORDER_CEILING 5 342 #else 343 /* Avoid stack overflow, because we need to save part of page table */ 344 #define SWAP_RA_ORDER_CEILING 3 345 #define SWAP_RA_PTE_CACHE_SIZE (1 << SWAP_RA_ORDER_CEILING) 346 #endif 347 348 struct vma_swap_readahead { 349 unsigned short win; 350 unsigned short offset; 351 unsigned short nr_pte; 352 #ifdef CONFIG_64BIT 353 pte_t *ptes; 354 #else 355 pte_t ptes[SWAP_RA_PTE_CACHE_SIZE]; 356 #endif 357 }; 358 359 static inline swp_entry_t folio_swap_entry(struct folio *folio) 360 { 361 swp_entry_t entry = { .val = page_private(&folio->page) }; 362 return entry; 363 } 364 365 static inline void folio_set_swap_entry(struct folio *folio, swp_entry_t entry) 366 { 367 folio->private = (void *)entry.val; 368 } 369 370 /* linux/mm/workingset.c */ 371 void workingset_age_nonresident(struct lruvec *lruvec, unsigned long nr_pages); 372 void *workingset_eviction(struct folio *folio, struct mem_cgroup *target_memcg); 373 void workingset_refault(struct folio *folio, void *shadow); 374 void workingset_activation(struct folio *folio); 375 376 /* Only track the nodes of mappings with shadow entries */ 377 void workingset_update_node(struct xa_node *node); 378 extern struct list_lru shadow_nodes; 379 #define mapping_set_update(xas, mapping) do { \ 380 if (!dax_mapping(mapping) && !shmem_mapping(mapping)) { \ 381 xas_set_update(xas, workingset_update_node); \ 382 xas_set_lru(xas, &shadow_nodes); \ 383 } \ 384 } while (0) 385 386 /* linux/mm/page_alloc.c */ 387 extern unsigned long totalreserve_pages; 388 389 /* Definition of global_zone_page_state not available yet */ 390 #define nr_free_pages() global_zone_page_state(NR_FREE_PAGES) 391 392 393 /* linux/mm/swap.c */ 394 void lru_note_cost(struct lruvec *lruvec, bool file, 395 unsigned int nr_io, unsigned int nr_rotated); 396 void lru_note_cost_refault(struct folio *); 397 void folio_add_lru(struct folio *); 398 void folio_add_lru_vma(struct folio *, struct vm_area_struct *); 399 void mark_page_accessed(struct page *); 400 void folio_mark_accessed(struct folio *); 401 402 extern atomic_t lru_disable_count; 403 404 static inline bool lru_cache_disabled(void) 405 { 406 return atomic_read(&lru_disable_count); 407 } 408 409 static inline void lru_cache_enable(void) 410 { 411 atomic_dec(&lru_disable_count); 412 } 413 414 extern void lru_cache_disable(void); 415 extern void lru_add_drain(void); 416 extern void lru_add_drain_cpu(int cpu); 417 extern void lru_add_drain_cpu_zone(struct zone *zone); 418 extern void lru_add_drain_all(void); 419 void folio_deactivate(struct folio *folio); 420 void folio_mark_lazyfree(struct folio *folio); 421 extern void swap_setup(void); 422 423 extern void lru_cache_add_inactive_or_unevictable(struct page *page, 424 struct vm_area_struct *vma); 425 426 /* linux/mm/vmscan.c */ 427 extern unsigned long zone_reclaimable_pages(struct zone *zone); 428 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order, 429 gfp_t gfp_mask, nodemask_t *mask); 430 431 #define MEMCG_RECLAIM_MAY_SWAP (1 << 1) 432 #define MEMCG_RECLAIM_PROACTIVE (1 << 2) 433 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg, 434 unsigned long nr_pages, 435 gfp_t gfp_mask, 436 unsigned int reclaim_options); 437 extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem, 438 gfp_t gfp_mask, bool noswap, 439 pg_data_t *pgdat, 440 unsigned long *nr_scanned); 441 extern unsigned long shrink_all_memory(unsigned long nr_pages); 442 extern int vm_swappiness; 443 long remove_mapping(struct address_space *mapping, struct folio *folio); 444 445 #ifdef CONFIG_NUMA 446 extern int node_reclaim_mode; 447 extern int sysctl_min_unmapped_ratio; 448 extern int sysctl_min_slab_ratio; 449 #else 450 #define node_reclaim_mode 0 451 #endif 452 453 static inline bool node_reclaim_enabled(void) 454 { 455 /* Is any node_reclaim_mode bit set? */ 456 return node_reclaim_mode & (RECLAIM_ZONE|RECLAIM_WRITE|RECLAIM_UNMAP); 457 } 458 459 void check_move_unevictable_folios(struct folio_batch *fbatch); 460 void check_move_unevictable_pages(struct pagevec *pvec); 461 462 extern void kswapd_run(int nid); 463 extern void kswapd_stop(int nid); 464 465 #ifdef CONFIG_SWAP 466 467 int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, 468 unsigned long nr_pages, sector_t start_block); 469 int generic_swapfile_activate(struct swap_info_struct *, struct file *, 470 sector_t *); 471 472 static inline unsigned long total_swapcache_pages(void) 473 { 474 return global_node_page_state(NR_SWAPCACHE); 475 } 476 477 extern void free_swap_cache(struct page *page); 478 extern void free_page_and_swap_cache(struct page *); 479 extern void free_pages_and_swap_cache(struct encoded_page **, int); 480 /* linux/mm/swapfile.c */ 481 extern atomic_long_t nr_swap_pages; 482 extern long total_swap_pages; 483 extern atomic_t nr_rotate_swap; 484 extern bool has_usable_swap(void); 485 486 /* Swap 50% full? Release swapcache more aggressively.. */ 487 static inline bool vm_swap_full(void) 488 { 489 return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages; 490 } 491 492 static inline long get_nr_swap_pages(void) 493 { 494 return atomic_long_read(&nr_swap_pages); 495 } 496 497 extern void si_swapinfo(struct sysinfo *); 498 swp_entry_t folio_alloc_swap(struct folio *folio); 499 bool folio_free_swap(struct folio *folio); 500 void put_swap_folio(struct folio *folio, swp_entry_t entry); 501 extern swp_entry_t get_swap_page_of_type(int); 502 extern int get_swap_pages(int n, swp_entry_t swp_entries[], int entry_size); 503 extern int add_swap_count_continuation(swp_entry_t, gfp_t); 504 extern void swap_shmem_alloc(swp_entry_t); 505 extern int swap_duplicate(swp_entry_t); 506 extern int swapcache_prepare(swp_entry_t); 507 extern void swap_free(swp_entry_t); 508 extern void swapcache_free_entries(swp_entry_t *entries, int n); 509 extern int free_swap_and_cache(swp_entry_t); 510 int swap_type_of(dev_t device, sector_t offset); 511 int find_first_swap(dev_t *device); 512 extern unsigned int count_swap_pages(int, int); 513 extern sector_t swapdev_block(int, pgoff_t); 514 extern int __swap_count(swp_entry_t entry); 515 extern int __swp_swapcount(swp_entry_t entry); 516 extern int swp_swapcount(swp_entry_t entry); 517 extern struct swap_info_struct *page_swap_info(struct page *); 518 extern struct swap_info_struct *swp_swap_info(swp_entry_t entry); 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 static inline struct swap_info_struct *swp_swap_info(swp_entry_t entry) 532 { 533 return NULL; 534 } 535 536 static inline struct swap_info_struct *get_swap_device(swp_entry_t entry) 537 { 538 return NULL; 539 } 540 541 static inline void put_swap_device(struct swap_info_struct *si) 542 { 543 } 544 545 #define get_nr_swap_pages() 0L 546 #define total_swap_pages 0L 547 #define total_swapcache_pages() 0UL 548 #define vm_swap_full() 0 549 550 #define si_swapinfo(val) \ 551 do { (val)->freeswap = (val)->totalswap = 0; } while (0) 552 /* only sparc can not include linux/pagemap.h in this file 553 * so leave put_page and release_pages undeclared... */ 554 #define free_page_and_swap_cache(page) \ 555 put_page(page) 556 #define free_pages_and_swap_cache(pages, nr) \ 557 release_pages((pages), (nr)); 558 559 /* used to sanity check ptes in zap_pte_range when CONFIG_SWAP=0 */ 560 #define free_swap_and_cache(e) is_pfn_swap_entry(e) 561 562 static inline void free_swap_cache(struct page *page) 563 { 564 } 565 566 static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask) 567 { 568 return 0; 569 } 570 571 static inline void swap_shmem_alloc(swp_entry_t swp) 572 { 573 } 574 575 static inline int swap_duplicate(swp_entry_t swp) 576 { 577 return 0; 578 } 579 580 static inline void swap_free(swp_entry_t swp) 581 { 582 } 583 584 static inline void put_swap_folio(struct folio *folio, swp_entry_t swp) 585 { 586 } 587 588 static inline int __swap_count(swp_entry_t entry) 589 { 590 return 0; 591 } 592 593 static inline int __swp_swapcount(swp_entry_t entry) 594 { 595 return 0; 596 } 597 598 static inline int swp_swapcount(swp_entry_t entry) 599 { 600 return 0; 601 } 602 603 static inline swp_entry_t folio_alloc_swap(struct folio *folio) 604 { 605 swp_entry_t entry; 606 entry.val = 0; 607 return entry; 608 } 609 610 static inline bool folio_free_swap(struct folio *folio) 611 { 612 return false; 613 } 614 615 static inline int add_swap_extent(struct swap_info_struct *sis, 616 unsigned long start_page, 617 unsigned long nr_pages, sector_t start_block) 618 { 619 return -EINVAL; 620 } 621 #endif /* CONFIG_SWAP */ 622 623 #ifdef CONFIG_THP_SWAP 624 extern int split_swap_cluster(swp_entry_t entry); 625 #else 626 static inline int split_swap_cluster(swp_entry_t entry) 627 { 628 return 0; 629 } 630 #endif 631 632 #ifdef CONFIG_MEMCG 633 static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg) 634 { 635 /* Cgroup2 doesn't have per-cgroup swappiness */ 636 if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) 637 return READ_ONCE(vm_swappiness); 638 639 /* root ? */ 640 if (mem_cgroup_disabled() || mem_cgroup_is_root(memcg)) 641 return READ_ONCE(vm_swappiness); 642 643 return READ_ONCE(memcg->swappiness); 644 } 645 #else 646 static inline int mem_cgroup_swappiness(struct mem_cgroup *mem) 647 { 648 return READ_ONCE(vm_swappiness); 649 } 650 #endif 651 652 #ifdef CONFIG_ZSWAP 653 extern u64 zswap_pool_total_size; 654 extern atomic_t zswap_stored_pages; 655 #endif 656 657 #if defined(CONFIG_SWAP) && defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP) 658 void __folio_throttle_swaprate(struct folio *folio, gfp_t gfp); 659 static inline void folio_throttle_swaprate(struct folio *folio, gfp_t gfp) 660 { 661 if (mem_cgroup_disabled()) 662 return; 663 __folio_throttle_swaprate(folio, gfp); 664 } 665 #else 666 static inline void folio_throttle_swaprate(struct folio *folio, gfp_t gfp) 667 { 668 } 669 #endif 670 671 #if defined(CONFIG_MEMCG) && defined(CONFIG_SWAP) 672 void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry); 673 int __mem_cgroup_try_charge_swap(struct folio *folio, swp_entry_t entry); 674 static inline int mem_cgroup_try_charge_swap(struct folio *folio, 675 swp_entry_t entry) 676 { 677 if (mem_cgroup_disabled()) 678 return 0; 679 return __mem_cgroup_try_charge_swap(folio, entry); 680 } 681 682 extern void __mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages); 683 static inline void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages) 684 { 685 if (mem_cgroup_disabled()) 686 return; 687 __mem_cgroup_uncharge_swap(entry, nr_pages); 688 } 689 690 extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg); 691 extern bool mem_cgroup_swap_full(struct folio *folio); 692 #else 693 static inline void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry) 694 { 695 } 696 697 static inline int mem_cgroup_try_charge_swap(struct folio *folio, 698 swp_entry_t entry) 699 { 700 return 0; 701 } 702 703 static inline void mem_cgroup_uncharge_swap(swp_entry_t entry, 704 unsigned int nr_pages) 705 { 706 } 707 708 static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg) 709 { 710 return get_nr_swap_pages(); 711 } 712 713 static inline bool mem_cgroup_swap_full(struct folio *folio) 714 { 715 return vm_swap_full(); 716 } 717 #endif 718 719 #endif /* __KERNEL__*/ 720 #endif /* _LINUX_SWAP_H */ 721