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 }; 223 224 #define SWAP_CLUSTER_MAX 32UL 225 #define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX 226 227 /* Bit flag in swap_map */ 228 #define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */ 229 #define COUNT_CONTINUED 0x80 /* Flag swap_map continuation for full count */ 230 231 /* Special value in first swap_map */ 232 #define SWAP_MAP_MAX 0x3e /* Max count */ 233 #define SWAP_MAP_BAD 0x3f /* Note page is bad */ 234 #define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs */ 235 236 /* Special value in each swap_map continuation */ 237 #define SWAP_CONT_MAX 0x7f /* Max count */ 238 239 /* 240 * We use this to track usage of a cluster. A cluster is a block of swap disk 241 * space with SWAPFILE_CLUSTER pages long and naturally aligns in disk. All 242 * free clusters are organized into a list. We fetch an entry from the list to 243 * get a free cluster. 244 * 245 * The flags field determines if a cluster is free. This is 246 * protected by cluster lock. 247 */ 248 struct swap_cluster_info { 249 spinlock_t lock; /* 250 * Protect swap_cluster_info fields 251 * other than list, and swap_info_struct->swap_map 252 * elements corresponding to the swap cluster. 253 */ 254 u16 count; 255 u8 flags; 256 u8 order; 257 struct list_head list; 258 }; 259 260 /* All on-list cluster must have a non-zero flag. */ 261 enum swap_cluster_flags { 262 CLUSTER_FLAG_NONE = 0, /* For temporary off-list cluster */ 263 CLUSTER_FLAG_FREE, 264 CLUSTER_FLAG_NONFULL, 265 CLUSTER_FLAG_FRAG, 266 /* Clusters with flags above are allocatable */ 267 CLUSTER_FLAG_USABLE = CLUSTER_FLAG_FRAG, 268 CLUSTER_FLAG_FULL, 269 CLUSTER_FLAG_DISCARD, 270 CLUSTER_FLAG_MAX, 271 }; 272 273 /* 274 * The first page in the swap file is the swap header, which is always marked 275 * bad to prevent it from being allocated as an entry. This also prevents the 276 * cluster to which it belongs being marked free. Therefore 0 is safe to use as 277 * a sentinel to indicate an entry is not valid. 278 */ 279 #define SWAP_ENTRY_INVALID 0 280 281 #ifdef CONFIG_THP_SWAP 282 #define SWAP_NR_ORDERS (PMD_ORDER + 1) 283 #else 284 #define SWAP_NR_ORDERS 1 285 #endif 286 287 /* 288 * We assign a cluster to each CPU, so each CPU can allocate swap entry from 289 * its own cluster and swapout sequentially. The purpose is to optimize swapout 290 * throughput. 291 */ 292 struct percpu_cluster { 293 local_lock_t lock; /* Protect the percpu_cluster above */ 294 unsigned int next[SWAP_NR_ORDERS]; /* Likely next allocation offset */ 295 }; 296 297 /* 298 * The in-memory structure used to track swap areas. 299 */ 300 struct swap_info_struct { 301 struct percpu_ref users; /* indicate and keep swap device valid. */ 302 unsigned long flags; /* SWP_USED etc: see above */ 303 signed short prio; /* swap priority of this type */ 304 struct plist_node list; /* entry in swap_active_head */ 305 signed char type; /* strange name for an index */ 306 unsigned int max; /* extent of the swap_map */ 307 unsigned char *swap_map; /* vmalloc'ed array of usage counts */ 308 unsigned long *zeromap; /* kvmalloc'ed bitmap to track zero pages */ 309 struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */ 310 struct list_head free_clusters; /* free clusters list */ 311 struct list_head full_clusters; /* full clusters list */ 312 struct list_head nonfull_clusters[SWAP_NR_ORDERS]; 313 /* list of cluster that contains at least one free slot */ 314 struct list_head frag_clusters[SWAP_NR_ORDERS]; 315 /* list of cluster that are fragmented or contented */ 316 atomic_long_t frag_cluster_nr[SWAP_NR_ORDERS]; 317 unsigned int pages; /* total of usable pages of swap */ 318 atomic_long_t inuse_pages; /* number of those currently in use */ 319 struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */ 320 struct percpu_cluster *global_cluster; /* Use one global cluster for rotating device */ 321 spinlock_t global_cluster_lock; /* Serialize usage of global cluster */ 322 struct rb_root swap_extent_root;/* root of the swap extent rbtree */ 323 struct block_device *bdev; /* swap device or bdev of swap file */ 324 struct file *swap_file; /* seldom referenced */ 325 struct completion comp; /* seldom referenced */ 326 spinlock_t lock; /* 327 * protect map scan related fields like 328 * swap_map, lowest_bit, highest_bit, 329 * inuse_pages, cluster_next, 330 * cluster_nr, lowest_alloc, 331 * highest_alloc, free/discard cluster 332 * list. other fields are only changed 333 * at swapon/swapoff, so are protected 334 * by swap_lock. changing flags need 335 * hold this lock and swap_lock. If 336 * both locks need hold, hold swap_lock 337 * first. 338 */ 339 spinlock_t cont_lock; /* 340 * protect swap count continuation page 341 * list. 342 */ 343 struct work_struct discard_work; /* discard worker */ 344 struct work_struct reclaim_work; /* reclaim worker */ 345 struct list_head discard_clusters; /* discard clusters list */ 346 struct plist_node avail_lists[]; /* 347 * entries in swap_avail_heads, one 348 * entry per node. 349 * Must be last as the number of the 350 * array is nr_node_ids, which is not 351 * a fixed value so have to allocate 352 * dynamically. 353 * And it has to be an array so that 354 * plist_for_each_* can work. 355 */ 356 }; 357 358 static inline swp_entry_t page_swap_entry(struct page *page) 359 { 360 struct folio *folio = page_folio(page); 361 swp_entry_t entry = folio->swap; 362 363 entry.val += folio_page_idx(folio, page); 364 return entry; 365 } 366 367 /* linux/mm/workingset.c */ 368 bool workingset_test_recent(void *shadow, bool file, bool *workingset, 369 bool flush); 370 void workingset_age_nonresident(struct lruvec *lruvec, unsigned long nr_pages); 371 void *workingset_eviction(struct folio *folio, struct mem_cgroup *target_memcg); 372 void workingset_refault(struct folio *folio, void *shadow); 373 void workingset_activation(struct folio *folio); 374 375 /* linux/mm/page_alloc.c */ 376 extern unsigned long totalreserve_pages; 377 378 /* Definition of global_zone_page_state not available yet */ 379 #define nr_free_pages() global_zone_page_state(NR_FREE_PAGES) 380 381 382 /* linux/mm/swap.c */ 383 void lru_note_cost(struct lruvec *lruvec, bool file, 384 unsigned int nr_io, unsigned int nr_rotated); 385 void lru_note_cost_refault(struct folio *); 386 void folio_add_lru(struct folio *); 387 void folio_add_lru_vma(struct folio *, struct vm_area_struct *); 388 void mark_page_accessed(struct page *); 389 void folio_mark_accessed(struct folio *); 390 391 extern atomic_t lru_disable_count; 392 393 static inline bool lru_cache_disabled(void) 394 { 395 return atomic_read(&lru_disable_count); 396 } 397 398 static inline void lru_cache_enable(void) 399 { 400 atomic_dec(&lru_disable_count); 401 } 402 403 extern void lru_cache_disable(void); 404 extern void lru_add_drain(void); 405 extern void lru_add_drain_cpu(int cpu); 406 extern void lru_add_drain_cpu_zone(struct zone *zone); 407 extern void lru_add_drain_all(void); 408 void folio_deactivate(struct folio *folio); 409 void folio_mark_lazyfree(struct folio *folio); 410 extern void swap_setup(void); 411 412 /* linux/mm/vmscan.c */ 413 extern unsigned long zone_reclaimable_pages(struct zone *zone); 414 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order, 415 gfp_t gfp_mask, nodemask_t *mask); 416 417 #define MEMCG_RECLAIM_MAY_SWAP (1 << 1) 418 #define MEMCG_RECLAIM_PROACTIVE (1 << 2) 419 #define MIN_SWAPPINESS 0 420 #define MAX_SWAPPINESS 200 421 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg, 422 unsigned long nr_pages, 423 gfp_t gfp_mask, 424 unsigned int reclaim_options, 425 int *swappiness); 426 extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem, 427 gfp_t gfp_mask, bool noswap, 428 pg_data_t *pgdat, 429 unsigned long *nr_scanned); 430 extern unsigned long shrink_all_memory(unsigned long nr_pages); 431 extern int vm_swappiness; 432 long remove_mapping(struct address_space *mapping, struct folio *folio); 433 434 #ifdef CONFIG_NUMA 435 extern int node_reclaim_mode; 436 extern int sysctl_min_unmapped_ratio; 437 extern int sysctl_min_slab_ratio; 438 #else 439 #define node_reclaim_mode 0 440 #endif 441 442 static inline bool node_reclaim_enabled(void) 443 { 444 /* Is any node_reclaim_mode bit set? */ 445 return node_reclaim_mode & (RECLAIM_ZONE|RECLAIM_WRITE|RECLAIM_UNMAP); 446 } 447 448 void check_move_unevictable_folios(struct folio_batch *fbatch); 449 450 extern void __meminit kswapd_run(int nid); 451 extern void __meminit kswapd_stop(int nid); 452 453 #ifdef CONFIG_SWAP 454 455 int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, 456 unsigned long nr_pages, sector_t start_block); 457 int generic_swapfile_activate(struct swap_info_struct *, struct file *, 458 sector_t *); 459 460 static inline unsigned long total_swapcache_pages(void) 461 { 462 return global_node_page_state(NR_SWAPCACHE); 463 } 464 465 void free_swap_cache(struct folio *folio); 466 void free_page_and_swap_cache(struct page *); 467 void free_pages_and_swap_cache(struct encoded_page **, int); 468 /* linux/mm/swapfile.c */ 469 extern atomic_long_t nr_swap_pages; 470 extern long total_swap_pages; 471 extern atomic_t nr_rotate_swap; 472 extern bool has_usable_swap(void); 473 474 /* Swap 50% full? Release swapcache more aggressively.. */ 475 static inline bool vm_swap_full(void) 476 { 477 return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages; 478 } 479 480 static inline long get_nr_swap_pages(void) 481 { 482 return atomic_long_read(&nr_swap_pages); 483 } 484 485 extern void si_swapinfo(struct sysinfo *); 486 swp_entry_t folio_alloc_swap(struct folio *folio); 487 bool folio_free_swap(struct folio *folio); 488 void put_swap_folio(struct folio *folio, swp_entry_t entry); 489 extern swp_entry_t get_swap_page_of_type(int); 490 extern int get_swap_pages(int n, swp_entry_t swp_entries[], int order); 491 extern int add_swap_count_continuation(swp_entry_t, gfp_t); 492 extern void swap_shmem_alloc(swp_entry_t, int); 493 extern int swap_duplicate(swp_entry_t); 494 extern int swapcache_prepare(swp_entry_t entry, int nr); 495 extern void swap_free_nr(swp_entry_t entry, int nr_pages); 496 extern void swapcache_free_entries(swp_entry_t *entries, int n); 497 extern void free_swap_and_cache_nr(swp_entry_t entry, int nr); 498 int swap_type_of(dev_t device, sector_t offset); 499 int find_first_swap(dev_t *device); 500 extern unsigned int count_swap_pages(int, int); 501 extern sector_t swapdev_block(int, pgoff_t); 502 extern int __swap_count(swp_entry_t entry); 503 extern int swap_swapcount(struct swap_info_struct *si, swp_entry_t entry); 504 extern int swp_swapcount(swp_entry_t entry); 505 struct swap_info_struct *swp_swap_info(swp_entry_t entry); 506 struct backing_dev_info; 507 extern int init_swap_address_space(unsigned int type, unsigned long nr_pages); 508 extern void exit_swap_address_space(unsigned int type); 509 extern struct swap_info_struct *get_swap_device(swp_entry_t entry); 510 sector_t swap_folio_sector(struct folio *folio); 511 512 static inline void put_swap_device(struct swap_info_struct *si) 513 { 514 percpu_ref_put(&si->users); 515 } 516 517 #else /* CONFIG_SWAP */ 518 static inline struct swap_info_struct *swp_swap_info(swp_entry_t entry) 519 { 520 return NULL; 521 } 522 523 static inline struct swap_info_struct *get_swap_device(swp_entry_t entry) 524 { 525 return NULL; 526 } 527 528 static inline void put_swap_device(struct swap_info_struct *si) 529 { 530 } 531 532 #define get_nr_swap_pages() 0L 533 #define total_swap_pages 0L 534 #define total_swapcache_pages() 0UL 535 #define vm_swap_full() 0 536 537 #define si_swapinfo(val) \ 538 do { (val)->freeswap = (val)->totalswap = 0; } while (0) 539 /* only sparc can not include linux/pagemap.h in this file 540 * so leave put_page and release_pages undeclared... */ 541 #define free_page_and_swap_cache(page) \ 542 put_page(page) 543 #define free_pages_and_swap_cache(pages, nr) \ 544 release_pages((pages), (nr)); 545 546 static inline void free_swap_and_cache_nr(swp_entry_t entry, int nr) 547 { 548 } 549 550 static inline void free_swap_cache(struct folio *folio) 551 { 552 } 553 554 static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask) 555 { 556 return 0; 557 } 558 559 static inline void swap_shmem_alloc(swp_entry_t swp, int nr) 560 { 561 } 562 563 static inline int swap_duplicate(swp_entry_t swp) 564 { 565 return 0; 566 } 567 568 static inline int swapcache_prepare(swp_entry_t swp, int nr) 569 { 570 return 0; 571 } 572 573 static inline void swap_free_nr(swp_entry_t entry, int nr_pages) 574 { 575 } 576 577 static inline void put_swap_folio(struct folio *folio, swp_entry_t swp) 578 { 579 } 580 581 static inline int __swap_count(swp_entry_t entry) 582 { 583 return 0; 584 } 585 586 static inline int swap_swapcount(struct swap_info_struct *si, swp_entry_t entry) 587 { 588 return 0; 589 } 590 591 static inline int swp_swapcount(swp_entry_t entry) 592 { 593 return 0; 594 } 595 596 static inline swp_entry_t folio_alloc_swap(struct folio *folio) 597 { 598 swp_entry_t entry; 599 entry.val = 0; 600 return entry; 601 } 602 603 static inline bool folio_free_swap(struct folio *folio) 604 { 605 return false; 606 } 607 608 static inline int add_swap_extent(struct swap_info_struct *sis, 609 unsigned long start_page, 610 unsigned long nr_pages, sector_t start_block) 611 { 612 return -EINVAL; 613 } 614 #endif /* CONFIG_SWAP */ 615 616 static inline void free_swap_and_cache(swp_entry_t entry) 617 { 618 free_swap_and_cache_nr(entry, 1); 619 } 620 621 static inline void swap_free(swp_entry_t entry) 622 { 623 swap_free_nr(entry, 1); 624 } 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 READ_ONCE(vm_swappiness); 632 633 /* root ? */ 634 if (mem_cgroup_disabled() || mem_cgroup_is_root(memcg)) 635 return READ_ONCE(vm_swappiness); 636 637 return READ_ONCE(memcg->swappiness); 638 } 639 #else 640 static inline int mem_cgroup_swappiness(struct mem_cgroup *mem) 641 { 642 return READ_ONCE(vm_swappiness); 643 } 644 #endif 645 646 #if defined(CONFIG_SWAP) && defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP) 647 void __folio_throttle_swaprate(struct folio *folio, gfp_t gfp); 648 static inline void folio_throttle_swaprate(struct folio *folio, gfp_t gfp) 649 { 650 if (mem_cgroup_disabled()) 651 return; 652 __folio_throttle_swaprate(folio, gfp); 653 } 654 #else 655 static inline void folio_throttle_swaprate(struct folio *folio, gfp_t gfp) 656 { 657 } 658 #endif 659 660 #if defined(CONFIG_MEMCG) && defined(CONFIG_SWAP) 661 void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry); 662 int __mem_cgroup_try_charge_swap(struct folio *folio, swp_entry_t entry); 663 static inline int mem_cgroup_try_charge_swap(struct folio *folio, 664 swp_entry_t entry) 665 { 666 if (mem_cgroup_disabled()) 667 return 0; 668 return __mem_cgroup_try_charge_swap(folio, entry); 669 } 670 671 extern void __mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages); 672 static inline void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages) 673 { 674 if (mem_cgroup_disabled()) 675 return; 676 __mem_cgroup_uncharge_swap(entry, nr_pages); 677 } 678 679 extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg); 680 extern bool mem_cgroup_swap_full(struct folio *folio); 681 #else 682 static inline void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry) 683 { 684 } 685 686 static inline int mem_cgroup_try_charge_swap(struct folio *folio, 687 swp_entry_t entry) 688 { 689 return 0; 690 } 691 692 static inline void mem_cgroup_uncharge_swap(swp_entry_t entry, 693 unsigned int nr_pages) 694 { 695 } 696 697 static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg) 698 { 699 return get_nr_swap_pages(); 700 } 701 702 static inline bool mem_cgroup_swap_full(struct folio *folio) 703 { 704 return vm_swap_full(); 705 } 706 #endif 707 708 #endif /* __KERNEL__*/ 709 #endif /* _LINUX_SWAP_H */ 710