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