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 #define SWP_SWAPIN_ERROR_NUM 1 59 #define SWP_SWAPIN_ERROR (MAX_SWAPFILES + SWP_HWPOISON_NUM + \ 60 SWP_MIGRATION_NUM + SWP_DEVICE_NUM + \ 61 SWP_PTE_MARKER_NUM) 62 /* 63 * PTE markers are used to persist information onto PTEs that are mapped with 64 * file-backed memories. As its name "PTE" hints, it should only be applied to 65 * the leaves of pgtables. 66 */ 67 #ifdef CONFIG_PTE_MARKER 68 #define SWP_PTE_MARKER_NUM 1 69 #define SWP_PTE_MARKER (MAX_SWAPFILES + SWP_HWPOISON_NUM + \ 70 SWP_MIGRATION_NUM + SWP_DEVICE_NUM) 71 #else 72 #define SWP_PTE_MARKER_NUM 0 73 #endif 74 75 /* 76 * Unaddressable device memory support. See include/linux/hmm.h and 77 * Documentation/mm/hmm.rst. Short description is we need struct pages for 78 * device memory that is unaddressable (inaccessible) by CPU, so that we can 79 * migrate part of a process memory to device memory. 80 * 81 * When a page is migrated from CPU to device, we set the CPU page table entry 82 * to a special SWP_DEVICE_{READ|WRITE} entry. 83 * 84 * When a page is mapped by the device for exclusive access we set the CPU page 85 * table entries to special SWP_DEVICE_EXCLUSIVE_* entries. 86 */ 87 #ifdef CONFIG_DEVICE_PRIVATE 88 #define SWP_DEVICE_NUM 4 89 #define SWP_DEVICE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM) 90 #define SWP_DEVICE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+1) 91 #define SWP_DEVICE_EXCLUSIVE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+2) 92 #define SWP_DEVICE_EXCLUSIVE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+3) 93 #else 94 #define SWP_DEVICE_NUM 0 95 #endif 96 97 /* 98 * Page migration support. 99 * 100 * SWP_MIGRATION_READ_EXCLUSIVE is only applicable to anonymous pages and 101 * indicates that the referenced (part of) an anonymous page is exclusive to 102 * a single process. For SWP_MIGRATION_WRITE, that information is implicit: 103 * (part of) an anonymous page that are mapped writable are exclusive to a 104 * single process. 105 */ 106 #ifdef CONFIG_MIGRATION 107 #define SWP_MIGRATION_NUM 3 108 #define SWP_MIGRATION_READ (MAX_SWAPFILES + SWP_HWPOISON_NUM) 109 #define SWP_MIGRATION_READ_EXCLUSIVE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1) 110 #define SWP_MIGRATION_WRITE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 2) 111 #else 112 #define SWP_MIGRATION_NUM 0 113 #endif 114 115 /* 116 * Handling of hardware poisoned pages with memory corruption. 117 */ 118 #ifdef CONFIG_MEMORY_FAILURE 119 #define SWP_HWPOISON_NUM 1 120 #define SWP_HWPOISON MAX_SWAPFILES 121 #else 122 #define SWP_HWPOISON_NUM 0 123 #endif 124 125 #define MAX_SWAPFILES \ 126 ((1 << MAX_SWAPFILES_SHIFT) - SWP_DEVICE_NUM - \ 127 SWP_MIGRATION_NUM - SWP_HWPOISON_NUM - \ 128 SWP_PTE_MARKER_NUM - SWP_SWAPIN_ERROR_NUM) 129 130 /* 131 * Magic header for a swap area. The first part of the union is 132 * what the swap magic looks like for the old (limited to 128MB) 133 * swap area format, the second part of the union adds - in the 134 * old reserved area - some extra information. Note that the first 135 * kilobyte is reserved for boot loader or disk label stuff... 136 * 137 * Having the magic at the end of the PAGE_SIZE makes detecting swap 138 * areas somewhat tricky on machines that support multiple page sizes. 139 * For 2.5 we'll probably want to move the magic to just beyond the 140 * bootbits... 141 */ 142 union swap_header { 143 struct { 144 char reserved[PAGE_SIZE - 10]; 145 char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */ 146 } magic; 147 struct { 148 char bootbits[1024]; /* Space for disklabel etc. */ 149 __u32 version; 150 __u32 last_page; 151 __u32 nr_badpages; 152 unsigned char sws_uuid[16]; 153 unsigned char sws_volume[16]; 154 __u32 padding[117]; 155 __u32 badpages[1]; 156 } info; 157 }; 158 159 /* 160 * current->reclaim_state points to one of these when a task is running 161 * memory reclaim 162 */ 163 struct reclaim_state { 164 unsigned long reclaimed_slab; 165 #ifdef CONFIG_LRU_GEN 166 /* per-thread mm walk data */ 167 struct lru_gen_mm_walk *mm_walk; 168 #endif 169 }; 170 171 #ifdef __KERNEL__ 172 173 struct address_space; 174 struct sysinfo; 175 struct writeback_control; 176 struct zone; 177 178 /* 179 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of 180 * disk blocks. A rbtree of swap extents maps the entire swapfile (Where the 181 * term `swapfile' refers to either a blockdevice or an IS_REG file). Apart 182 * from setup, they're handled identically. 183 * 184 * We always assume that blocks are of size PAGE_SIZE. 185 */ 186 struct swap_extent { 187 struct rb_node rb_node; 188 pgoff_t start_page; 189 pgoff_t nr_pages; 190 sector_t start_block; 191 }; 192 193 /* 194 * Max bad pages in the new format.. 195 */ 196 #define MAX_SWAP_BADPAGES \ 197 ((offsetof(union swap_header, magic.magic) - \ 198 offsetof(union swap_header, info.badpages)) / sizeof(int)) 199 200 enum { 201 SWP_USED = (1 << 0), /* is slot in swap_info[] used? */ 202 SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */ 203 SWP_DISCARDABLE = (1 << 2), /* blkdev support discard */ 204 SWP_DISCARDING = (1 << 3), /* now discarding a free cluster */ 205 SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */ 206 SWP_CONTINUED = (1 << 5), /* swap_map has count continuation */ 207 SWP_BLKDEV = (1 << 6), /* its a block device */ 208 SWP_ACTIVATED = (1 << 7), /* set after swap_activate success */ 209 SWP_FS_OPS = (1 << 8), /* swapfile operations go through fs */ 210 SWP_AREA_DISCARD = (1 << 9), /* single-time swap area discards */ 211 SWP_PAGE_DISCARD = (1 << 10), /* freed swap page-cluster discards */ 212 SWP_STABLE_WRITES = (1 << 11), /* no overwrite PG_writeback pages */ 213 SWP_SYNCHRONOUS_IO = (1 << 12), /* synchronous IO is efficient */ 214 /* add others here before... */ 215 SWP_SCANNING = (1 << 14), /* refcount in scan_swap_map */ 216 }; 217 218 #define SWAP_CLUSTER_MAX 32UL 219 #define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX 220 221 /* Bit flag in swap_map */ 222 #define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */ 223 #define COUNT_CONTINUED 0x80 /* Flag swap_map continuation for full count */ 224 225 /* Special value in first swap_map */ 226 #define SWAP_MAP_MAX 0x3e /* Max count */ 227 #define SWAP_MAP_BAD 0x3f /* Note page is bad */ 228 #define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs */ 229 230 /* Special value in each swap_map continuation */ 231 #define SWAP_CONT_MAX 0x7f /* Max count */ 232 233 /* 234 * We use this to track usage of a cluster. A cluster is a block of swap disk 235 * space with SWAPFILE_CLUSTER pages long and naturally aligns in disk. All 236 * free clusters are organized into a list. We fetch an entry from the list to 237 * get a free cluster. 238 * 239 * The data field stores next cluster if the cluster is free or cluster usage 240 * counter otherwise. The flags field determines if a cluster is free. This is 241 * protected by swap_info_struct.lock. 242 */ 243 struct swap_cluster_info { 244 spinlock_t lock; /* 245 * Protect swap_cluster_info fields 246 * and swap_info_struct->swap_map 247 * elements correspond to the swap 248 * cluster 249 */ 250 unsigned int data:24; 251 unsigned int flags:8; 252 }; 253 #define CLUSTER_FLAG_FREE 1 /* This cluster is free */ 254 #define CLUSTER_FLAG_NEXT_NULL 2 /* This cluster has no next cluster */ 255 #define CLUSTER_FLAG_HUGE 4 /* This cluster is backing a transparent huge page */ 256 257 /* 258 * We assign a cluster to each CPU, so each CPU can allocate swap entry from 259 * its own cluster and swapout sequentially. The purpose is to optimize swapout 260 * throughput. 261 */ 262 struct percpu_cluster { 263 struct swap_cluster_info index; /* Current cluster index */ 264 unsigned int next; /* Likely next allocation offset */ 265 }; 266 267 struct swap_cluster_list { 268 struct swap_cluster_info head; 269 struct swap_cluster_info tail; 270 }; 271 272 /* 273 * The in-memory structure used to track swap areas. 274 */ 275 struct swap_info_struct { 276 struct percpu_ref users; /* indicate and keep swap device valid. */ 277 unsigned long flags; /* SWP_USED etc: see above */ 278 signed short prio; /* swap priority of this type */ 279 struct plist_node list; /* entry in swap_active_head */ 280 signed char type; /* strange name for an index */ 281 unsigned int max; /* extent of the swap_map */ 282 unsigned char *swap_map; /* vmalloc'ed array of usage counts */ 283 struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */ 284 struct swap_cluster_list free_clusters; /* free clusters list */ 285 unsigned int lowest_bit; /* index of first free in swap_map */ 286 unsigned int highest_bit; /* index of last free in swap_map */ 287 unsigned int pages; /* total of usable pages of swap */ 288 unsigned int inuse_pages; /* number of those currently in use */ 289 unsigned int cluster_next; /* likely index for next allocation */ 290 unsigned int cluster_nr; /* countdown to next cluster search */ 291 unsigned int __percpu *cluster_next_cpu; /*percpu index for next allocation */ 292 struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */ 293 struct rb_root swap_extent_root;/* root of the swap extent rbtree */ 294 struct block_device *bdev; /* swap device or bdev of swap file */ 295 struct file *swap_file; /* seldom referenced */ 296 unsigned int old_block_size; /* seldom referenced */ 297 struct completion comp; /* seldom referenced */ 298 #ifdef CONFIG_FRONTSWAP 299 unsigned long *frontswap_map; /* frontswap in-use, one bit per page */ 300 atomic_t frontswap_pages; /* frontswap pages in-use counter */ 301 #endif 302 spinlock_t lock; /* 303 * protect map scan related fields like 304 * swap_map, lowest_bit, highest_bit, 305 * inuse_pages, cluster_next, 306 * cluster_nr, lowest_alloc, 307 * highest_alloc, free/discard cluster 308 * list. other fields are only changed 309 * at swapon/swapoff, so are protected 310 * by swap_lock. changing flags need 311 * hold this lock and swap_lock. If 312 * both locks need hold, hold swap_lock 313 * first. 314 */ 315 spinlock_t cont_lock; /* 316 * protect swap count continuation page 317 * list. 318 */ 319 struct work_struct discard_work; /* discard worker */ 320 struct swap_cluster_list discard_clusters; /* discard clusters list */ 321 struct plist_node avail_lists[]; /* 322 * entries in swap_avail_heads, one 323 * entry per node. 324 * Must be last as the number of the 325 * array is nr_node_ids, which is not 326 * a fixed value so have to allocate 327 * dynamically. 328 * And it has to be an array so that 329 * plist_for_each_* can work. 330 */ 331 }; 332 333 #ifdef CONFIG_64BIT 334 #define SWAP_RA_ORDER_CEILING 5 335 #else 336 /* Avoid stack overflow, because we need to save part of page table */ 337 #define SWAP_RA_ORDER_CEILING 3 338 #define SWAP_RA_PTE_CACHE_SIZE (1 << SWAP_RA_ORDER_CEILING) 339 #endif 340 341 struct vma_swap_readahead { 342 unsigned short win; 343 unsigned short offset; 344 unsigned short nr_pte; 345 #ifdef CONFIG_64BIT 346 pte_t *ptes; 347 #else 348 pte_t ptes[SWAP_RA_PTE_CACHE_SIZE]; 349 #endif 350 }; 351 352 static inline swp_entry_t folio_swap_entry(struct folio *folio) 353 { 354 swp_entry_t entry = { .val = page_private(&folio->page) }; 355 return entry; 356 } 357 358 static inline void folio_set_swap_entry(struct folio *folio, swp_entry_t entry) 359 { 360 folio->private = (void *)entry.val; 361 } 362 363 /* linux/mm/workingset.c */ 364 void workingset_age_nonresident(struct lruvec *lruvec, unsigned long nr_pages); 365 void *workingset_eviction(struct folio *folio, struct mem_cgroup *target_memcg); 366 void workingset_refault(struct folio *folio, void *shadow); 367 void workingset_activation(struct folio *folio); 368 369 /* Only track the nodes of mappings with shadow entries */ 370 void workingset_update_node(struct xa_node *node); 371 extern struct list_lru shadow_nodes; 372 #define mapping_set_update(xas, mapping) do { \ 373 if (!dax_mapping(mapping) && !shmem_mapping(mapping)) { \ 374 xas_set_update(xas, workingset_update_node); \ 375 xas_set_lru(xas, &shadow_nodes); \ 376 } \ 377 } while (0) 378 379 /* linux/mm/page_alloc.c */ 380 extern unsigned long totalreserve_pages; 381 382 /* Definition of global_zone_page_state not available yet */ 383 #define nr_free_pages() global_zone_page_state(NR_FREE_PAGES) 384 385 386 /* linux/mm/swap.c */ 387 void lru_note_cost(struct lruvec *lruvec, bool file, unsigned int nr_pages); 388 void lru_note_cost_folio(struct folio *); 389 void folio_add_lru(struct folio *); 390 void folio_add_lru_vma(struct folio *, struct vm_area_struct *); 391 void lru_cache_add(struct page *); 392 void mark_page_accessed(struct page *); 393 void folio_mark_accessed(struct folio *); 394 395 extern atomic_t lru_disable_count; 396 397 static inline bool lru_cache_disabled(void) 398 { 399 return atomic_read(&lru_disable_count); 400 } 401 402 static inline void lru_cache_enable(void) 403 { 404 atomic_dec(&lru_disable_count); 405 } 406 407 extern void lru_cache_disable(void); 408 extern void lru_add_drain(void); 409 extern void lru_add_drain_cpu(int cpu); 410 extern void lru_add_drain_cpu_zone(struct zone *zone); 411 extern void lru_add_drain_all(void); 412 extern void deactivate_page(struct page *page); 413 extern void mark_page_lazyfree(struct page *page); 414 extern void swap_setup(void); 415 416 extern void lru_cache_add_inactive_or_unevictable(struct page *page, 417 struct vm_area_struct *vma); 418 419 /* linux/mm/vmscan.c */ 420 extern unsigned long zone_reclaimable_pages(struct zone *zone); 421 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order, 422 gfp_t gfp_mask, nodemask_t *mask); 423 424 #define MEMCG_RECLAIM_MAY_SWAP (1 << 1) 425 #define MEMCG_RECLAIM_PROACTIVE (1 << 2) 426 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg, 427 unsigned long nr_pages, 428 gfp_t gfp_mask, 429 unsigned int reclaim_options); 430 extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem, 431 gfp_t gfp_mask, bool noswap, 432 pg_data_t *pgdat, 433 unsigned long *nr_scanned); 434 extern unsigned long shrink_all_memory(unsigned long nr_pages); 435 extern int vm_swappiness; 436 long remove_mapping(struct address_space *mapping, struct folio *folio); 437 438 extern unsigned long reclaim_pages(struct list_head *page_list); 439 #ifdef CONFIG_NUMA 440 extern int node_reclaim_mode; 441 extern int sysctl_min_unmapped_ratio; 442 extern int sysctl_min_slab_ratio; 443 #else 444 #define node_reclaim_mode 0 445 #endif 446 447 static inline bool node_reclaim_enabled(void) 448 { 449 /* Is any node_reclaim_mode bit set? */ 450 return node_reclaim_mode & (RECLAIM_ZONE|RECLAIM_WRITE|RECLAIM_UNMAP); 451 } 452 453 void check_move_unevictable_folios(struct folio_batch *fbatch); 454 void check_move_unevictable_pages(struct pagevec *pvec); 455 456 extern void kswapd_run(int nid); 457 extern void kswapd_stop(int nid); 458 459 #ifdef CONFIG_SWAP 460 461 int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, 462 unsigned long nr_pages, sector_t start_block); 463 int generic_swapfile_activate(struct swap_info_struct *, struct file *, 464 sector_t *); 465 466 static inline unsigned long total_swapcache_pages(void) 467 { 468 return global_node_page_state(NR_SWAPCACHE); 469 } 470 471 extern void free_swap_cache(struct page *page); 472 extern void free_page_and_swap_cache(struct page *); 473 extern void free_pages_and_swap_cache(struct page **, int); 474 /* linux/mm/swapfile.c */ 475 extern atomic_long_t nr_swap_pages; 476 extern long total_swap_pages; 477 extern atomic_t nr_rotate_swap; 478 extern bool has_usable_swap(void); 479 480 /* Swap 50% full? Release swapcache more aggressively.. */ 481 static inline bool vm_swap_full(void) 482 { 483 return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages; 484 } 485 486 static inline long get_nr_swap_pages(void) 487 { 488 return atomic_long_read(&nr_swap_pages); 489 } 490 491 extern void si_swapinfo(struct sysinfo *); 492 swp_entry_t folio_alloc_swap(struct folio *folio); 493 bool folio_free_swap(struct folio *folio); 494 void put_swap_folio(struct folio *folio, swp_entry_t entry); 495 extern swp_entry_t get_swap_page_of_type(int); 496 extern int get_swap_pages(int n, swp_entry_t swp_entries[], int entry_size); 497 extern int add_swap_count_continuation(swp_entry_t, gfp_t); 498 extern void swap_shmem_alloc(swp_entry_t); 499 extern int swap_duplicate(swp_entry_t); 500 extern int swapcache_prepare(swp_entry_t); 501 extern void swap_free(swp_entry_t); 502 extern void swapcache_free_entries(swp_entry_t *entries, int n); 503 extern int free_swap_and_cache(swp_entry_t); 504 int swap_type_of(dev_t device, sector_t offset); 505 int find_first_swap(dev_t *device); 506 extern unsigned int count_swap_pages(int, int); 507 extern sector_t swapdev_block(int, pgoff_t); 508 extern int __swap_count(swp_entry_t entry); 509 extern int __swp_swapcount(swp_entry_t entry); 510 extern int swp_swapcount(swp_entry_t entry); 511 extern struct swap_info_struct *page_swap_info(struct page *); 512 extern struct swap_info_struct *swp_swap_info(swp_entry_t entry); 513 struct backing_dev_info; 514 extern int init_swap_address_space(unsigned int type, unsigned long nr_pages); 515 extern void exit_swap_address_space(unsigned int type); 516 extern struct swap_info_struct *get_swap_device(swp_entry_t entry); 517 sector_t swap_page_sector(struct page *page); 518 519 static inline void put_swap_device(struct swap_info_struct *si) 520 { 521 percpu_ref_put(&si->users); 522 } 523 524 #else /* CONFIG_SWAP */ 525 static inline struct swap_info_struct *swp_swap_info(swp_entry_t entry) 526 { 527 return NULL; 528 } 529 530 static inline struct swap_info_struct *get_swap_device(swp_entry_t entry) 531 { 532 return NULL; 533 } 534 535 static inline void put_swap_device(struct swap_info_struct *si) 536 { 537 } 538 539 #define get_nr_swap_pages() 0L 540 #define total_swap_pages 0L 541 #define total_swapcache_pages() 0UL 542 #define vm_swap_full() 0 543 544 #define si_swapinfo(val) \ 545 do { (val)->freeswap = (val)->totalswap = 0; } while (0) 546 /* only sparc can not include linux/pagemap.h in this file 547 * so leave put_page and release_pages undeclared... */ 548 #define free_page_and_swap_cache(page) \ 549 put_page(page) 550 #define free_pages_and_swap_cache(pages, nr) \ 551 release_pages((pages), (nr)); 552 553 /* used to sanity check ptes in zap_pte_range when CONFIG_SWAP=0 */ 554 #define free_swap_and_cache(e) is_pfn_swap_entry(e) 555 556 static inline void free_swap_cache(struct page *page) 557 { 558 } 559 560 static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask) 561 { 562 return 0; 563 } 564 565 static inline void swap_shmem_alloc(swp_entry_t swp) 566 { 567 } 568 569 static inline int swap_duplicate(swp_entry_t swp) 570 { 571 return 0; 572 } 573 574 static inline void swap_free(swp_entry_t swp) 575 { 576 } 577 578 static inline void put_swap_folio(struct folio *folio, swp_entry_t swp) 579 { 580 } 581 582 static inline int __swap_count(swp_entry_t entry) 583 { 584 return 0; 585 } 586 587 static inline int __swp_swapcount(swp_entry_t entry) 588 { 589 return 0; 590 } 591 592 static inline int swp_swapcount(swp_entry_t entry) 593 { 594 return 0; 595 } 596 597 static inline swp_entry_t folio_alloc_swap(struct folio *folio) 598 { 599 swp_entry_t entry; 600 entry.val = 0; 601 return entry; 602 } 603 604 static inline bool folio_free_swap(struct folio *folio) 605 { 606 return false; 607 } 608 609 static inline int add_swap_extent(struct swap_info_struct *sis, 610 unsigned long start_page, 611 unsigned long nr_pages, sector_t start_block) 612 { 613 return -EINVAL; 614 } 615 #endif /* CONFIG_SWAP */ 616 617 #ifdef CONFIG_THP_SWAP 618 extern int split_swap_cluster(swp_entry_t entry); 619 #else 620 static inline int split_swap_cluster(swp_entry_t entry) 621 { 622 return 0; 623 } 624 #endif 625 626 #ifdef CONFIG_MEMCG 627 static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg) 628 { 629 /* Cgroup2 doesn't have per-cgroup swappiness */ 630 if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) 631 return vm_swappiness; 632 633 /* root ? */ 634 if (mem_cgroup_disabled() || mem_cgroup_is_root(memcg)) 635 return vm_swappiness; 636 637 return memcg->swappiness; 638 } 639 #else 640 static inline int mem_cgroup_swappiness(struct mem_cgroup *mem) 641 { 642 return vm_swappiness; 643 } 644 #endif 645 646 #ifdef CONFIG_ZSWAP 647 extern u64 zswap_pool_total_size; 648 extern atomic_t zswap_stored_pages; 649 #endif 650 651 #if defined(CONFIG_SWAP) && defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP) 652 extern void __cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask); 653 static inline void cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask) 654 { 655 if (mem_cgroup_disabled()) 656 return; 657 __cgroup_throttle_swaprate(page, gfp_mask); 658 } 659 #else 660 static inline void cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask) 661 { 662 } 663 #endif 664 static inline void folio_throttle_swaprate(struct folio *folio, gfp_t gfp) 665 { 666 cgroup_throttle_swaprate(&folio->page, gfp); 667 } 668 669 #if defined(CONFIG_MEMCG) && defined(CONFIG_SWAP) 670 void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry); 671 int __mem_cgroup_try_charge_swap(struct folio *folio, swp_entry_t entry); 672 static inline int mem_cgroup_try_charge_swap(struct folio *folio, 673 swp_entry_t entry) 674 { 675 if (mem_cgroup_disabled()) 676 return 0; 677 return __mem_cgroup_try_charge_swap(folio, entry); 678 } 679 680 extern void __mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages); 681 static inline void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages) 682 { 683 if (mem_cgroup_disabled()) 684 return; 685 __mem_cgroup_uncharge_swap(entry, nr_pages); 686 } 687 688 extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg); 689 extern bool mem_cgroup_swap_full(struct folio *folio); 690 #else 691 static inline void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry) 692 { 693 } 694 695 static inline int mem_cgroup_try_charge_swap(struct folio *folio, 696 swp_entry_t entry) 697 { 698 return 0; 699 } 700 701 static inline void mem_cgroup_uncharge_swap(swp_entry_t entry, 702 unsigned int nr_pages) 703 { 704 } 705 706 static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg) 707 { 708 return get_nr_swap_pages(); 709 } 710 711 static inline bool mem_cgroup_swap_full(struct folio *folio) 712 { 713 return vm_swap_full(); 714 } 715 #endif 716 717 #endif /* __KERNEL__*/ 718 #endif /* _LINUX_SWAP_H */ 719