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 SWAP_CLUSTER_MAX_SKIPPED (SWAP_CLUSTER_MAX << 10) 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 flags field determines if a cluster is free. This is 247 * protected by cluster lock. 248 */ 249 struct swap_cluster_info { 250 spinlock_t lock; /* 251 * Protect swap_cluster_info fields 252 * other than list, and swap_info_struct->swap_map 253 * elements corresponding to the swap cluster. 254 */ 255 u16 count; 256 u8 flags; 257 u8 order; 258 struct list_head list; 259 }; 260 261 /* All on-list cluster must have a non-zero flag. */ 262 enum swap_cluster_flags { 263 CLUSTER_FLAG_NONE = 0, /* For temporary off-list cluster */ 264 CLUSTER_FLAG_FREE, 265 CLUSTER_FLAG_NONFULL, 266 CLUSTER_FLAG_FRAG, 267 /* Clusters with flags above are allocatable */ 268 CLUSTER_FLAG_USABLE = CLUSTER_FLAG_FRAG, 269 CLUSTER_FLAG_FULL, 270 CLUSTER_FLAG_DISCARD, 271 CLUSTER_FLAG_MAX, 272 }; 273 274 /* 275 * The first page in the swap file is the swap header, which is always marked 276 * bad to prevent it from being allocated as an entry. This also prevents the 277 * cluster to which it belongs being marked free. Therefore 0 is safe to use as 278 * a sentinel to indicate an entry is not valid. 279 */ 280 #define SWAP_ENTRY_INVALID 0 281 282 #ifdef CONFIG_THP_SWAP 283 #define SWAP_NR_ORDERS (PMD_ORDER + 1) 284 #else 285 #define SWAP_NR_ORDERS 1 286 #endif 287 288 /* 289 * We assign a cluster to each CPU, so each CPU can allocate swap entry from 290 * its own cluster and swapout sequentially. The purpose is to optimize swapout 291 * throughput. 292 */ 293 struct percpu_cluster { 294 local_lock_t lock; /* Protect the percpu_cluster above */ 295 unsigned int next[SWAP_NR_ORDERS]; /* Likely next allocation offset */ 296 }; 297 298 /* 299 * The in-memory structure used to track swap areas. 300 */ 301 struct swap_info_struct { 302 struct percpu_ref users; /* indicate and keep swap device valid. */ 303 unsigned long flags; /* SWP_USED etc: see above */ 304 signed short prio; /* swap priority of this type */ 305 struct plist_node list; /* entry in swap_active_head */ 306 signed char type; /* strange name for an index */ 307 unsigned int max; /* extent of the swap_map */ 308 unsigned char *swap_map; /* vmalloc'ed array of usage counts */ 309 unsigned long *zeromap; /* kvmalloc'ed bitmap to track zero pages */ 310 struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */ 311 struct list_head free_clusters; /* free clusters list */ 312 struct list_head full_clusters; /* full clusters list */ 313 struct list_head nonfull_clusters[SWAP_NR_ORDERS]; 314 /* list of cluster that contains at least one free slot */ 315 struct list_head frag_clusters[SWAP_NR_ORDERS]; 316 /* list of cluster that are fragmented or contented */ 317 atomic_long_t frag_cluster_nr[SWAP_NR_ORDERS]; 318 unsigned int pages; /* total of usable pages of swap */ 319 atomic_long_t inuse_pages; /* number of those currently in use */ 320 struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */ 321 struct percpu_cluster *global_cluster; /* Use one global cluster for rotating device */ 322 spinlock_t global_cluster_lock; /* Serialize usage of global cluster */ 323 struct rb_root swap_extent_root;/* root of the swap extent rbtree */ 324 struct block_device *bdev; /* swap device or bdev of swap file */ 325 struct file *swap_file; /* seldom referenced */ 326 struct completion comp; /* seldom referenced */ 327 spinlock_t lock; /* 328 * protect map scan related fields like 329 * swap_map, lowest_bit, highest_bit, 330 * inuse_pages, cluster_next, 331 * cluster_nr, lowest_alloc, 332 * highest_alloc, free/discard cluster 333 * list. other fields are only changed 334 * at swapon/swapoff, so are protected 335 * by swap_lock. changing flags need 336 * hold this lock and swap_lock. If 337 * both locks need hold, hold swap_lock 338 * first. 339 */ 340 spinlock_t cont_lock; /* 341 * protect swap count continuation page 342 * list. 343 */ 344 struct work_struct discard_work; /* discard worker */ 345 struct work_struct reclaim_work; /* reclaim worker */ 346 struct list_head discard_clusters; /* discard clusters list */ 347 struct plist_node avail_lists[]; /* 348 * entries in swap_avail_heads, one 349 * entry per node. 350 * Must be last as the number of the 351 * array is nr_node_ids, which is not 352 * a fixed value so have to allocate 353 * dynamically. 354 * And it has to be an array so that 355 * plist_for_each_* can work. 356 */ 357 }; 358 359 static inline swp_entry_t page_swap_entry(struct page *page) 360 { 361 struct folio *folio = page_folio(page); 362 swp_entry_t entry = folio->swap; 363 364 entry.val += folio_page_idx(folio, page); 365 return entry; 366 } 367 368 /* linux/mm/workingset.c */ 369 bool workingset_test_recent(void *shadow, bool file, bool *workingset, 370 bool flush); 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 /* linux/mm/page_alloc.c */ 377 extern unsigned long totalreserve_pages; 378 379 /* Definition of global_zone_page_state not available yet */ 380 #define nr_free_pages() global_zone_page_state(NR_FREE_PAGES) 381 382 383 /* linux/mm/swap.c */ 384 void lru_note_cost(struct lruvec *lruvec, bool file, 385 unsigned int nr_io, unsigned int nr_rotated); 386 void lru_note_cost_refault(struct folio *); 387 void folio_add_lru(struct folio *); 388 void folio_add_lru_vma(struct folio *, struct vm_area_struct *); 389 void mark_page_accessed(struct page *); 390 void folio_mark_accessed(struct folio *); 391 392 extern atomic_t lru_disable_count; 393 394 static inline bool lru_cache_disabled(void) 395 { 396 return atomic_read(&lru_disable_count); 397 } 398 399 static inline void lru_cache_enable(void) 400 { 401 atomic_dec(&lru_disable_count); 402 } 403 404 extern void lru_cache_disable(void); 405 extern void lru_add_drain(void); 406 extern void lru_add_drain_cpu(int cpu); 407 extern void lru_add_drain_cpu_zone(struct zone *zone); 408 extern void lru_add_drain_all(void); 409 void folio_deactivate(struct folio *folio); 410 void folio_mark_lazyfree(struct folio *folio); 411 extern void swap_setup(void); 412 413 /* linux/mm/vmscan.c */ 414 extern unsigned long zone_reclaimable_pages(struct zone *zone); 415 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order, 416 gfp_t gfp_mask, nodemask_t *mask); 417 418 #define MEMCG_RECLAIM_MAY_SWAP (1 << 1) 419 #define MEMCG_RECLAIM_PROACTIVE (1 << 2) 420 #define MIN_SWAPPINESS 0 421 #define MAX_SWAPPINESS 200 422 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg, 423 unsigned long nr_pages, 424 gfp_t gfp_mask, 425 unsigned int reclaim_options, 426 int *swappiness); 427 extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem, 428 gfp_t gfp_mask, bool noswap, 429 pg_data_t *pgdat, 430 unsigned long *nr_scanned); 431 extern unsigned long shrink_all_memory(unsigned long nr_pages); 432 extern int vm_swappiness; 433 long remove_mapping(struct address_space *mapping, struct folio *folio); 434 435 #ifdef CONFIG_NUMA 436 extern int node_reclaim_mode; 437 extern int sysctl_min_unmapped_ratio; 438 extern int sysctl_min_slab_ratio; 439 #else 440 #define node_reclaim_mode 0 441 #endif 442 443 static inline bool node_reclaim_enabled(void) 444 { 445 /* Is any node_reclaim_mode bit set? */ 446 return node_reclaim_mode & (RECLAIM_ZONE|RECLAIM_WRITE|RECLAIM_UNMAP); 447 } 448 449 void check_move_unevictable_folios(struct folio_batch *fbatch); 450 451 extern void __meminit kswapd_run(int nid); 452 extern void __meminit kswapd_stop(int nid); 453 454 #ifdef CONFIG_SWAP 455 456 int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, 457 unsigned long nr_pages, sector_t start_block); 458 int generic_swapfile_activate(struct swap_info_struct *, struct file *, 459 sector_t *); 460 461 static inline unsigned long total_swapcache_pages(void) 462 { 463 return global_node_page_state(NR_SWAPCACHE); 464 } 465 466 void free_swap_cache(struct folio *folio); 467 void free_page_and_swap_cache(struct page *); 468 void free_pages_and_swap_cache(struct encoded_page **, int); 469 /* linux/mm/swapfile.c */ 470 extern atomic_long_t nr_swap_pages; 471 extern long total_swap_pages; 472 extern atomic_t nr_rotate_swap; 473 extern bool has_usable_swap(void); 474 475 /* Swap 50% full? Release swapcache more aggressively.. */ 476 static inline bool vm_swap_full(void) 477 { 478 return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages; 479 } 480 481 static inline long get_nr_swap_pages(void) 482 { 483 return atomic_long_read(&nr_swap_pages); 484 } 485 486 extern void si_swapinfo(struct sysinfo *); 487 swp_entry_t folio_alloc_swap(struct folio *folio); 488 bool folio_free_swap(struct folio *folio); 489 void put_swap_folio(struct folio *folio, swp_entry_t entry); 490 extern swp_entry_t get_swap_page_of_type(int); 491 extern int get_swap_pages(int n, swp_entry_t swp_entries[], int order); 492 extern int add_swap_count_continuation(swp_entry_t, gfp_t); 493 extern void swap_shmem_alloc(swp_entry_t, int); 494 extern int swap_duplicate(swp_entry_t); 495 extern int swapcache_prepare(swp_entry_t entry, int nr); 496 extern void swap_free_nr(swp_entry_t entry, int nr_pages); 497 extern void swapcache_free_entries(swp_entry_t *entries, int n); 498 extern void free_swap_and_cache_nr(swp_entry_t entry, int nr); 499 int swap_type_of(dev_t device, sector_t offset); 500 int find_first_swap(dev_t *device); 501 extern unsigned int count_swap_pages(int, int); 502 extern sector_t swapdev_block(int, pgoff_t); 503 extern int __swap_count(swp_entry_t entry); 504 extern int swap_swapcount(struct swap_info_struct *si, swp_entry_t entry); 505 extern int swp_swapcount(swp_entry_t entry); 506 struct swap_info_struct *swp_swap_info(swp_entry_t entry); 507 struct backing_dev_info; 508 extern int init_swap_address_space(unsigned int type, unsigned long nr_pages); 509 extern void exit_swap_address_space(unsigned int type); 510 extern struct swap_info_struct *get_swap_device(swp_entry_t entry); 511 sector_t swap_folio_sector(struct folio *folio); 512 513 static inline void put_swap_device(struct swap_info_struct *si) 514 { 515 percpu_ref_put(&si->users); 516 } 517 518 #else /* CONFIG_SWAP */ 519 static inline struct swap_info_struct *swp_swap_info(swp_entry_t entry) 520 { 521 return NULL; 522 } 523 524 static inline struct swap_info_struct *get_swap_device(swp_entry_t entry) 525 { 526 return NULL; 527 } 528 529 static inline void put_swap_device(struct swap_info_struct *si) 530 { 531 } 532 533 #define get_nr_swap_pages() 0L 534 #define total_swap_pages 0L 535 #define total_swapcache_pages() 0UL 536 #define vm_swap_full() 0 537 538 #define si_swapinfo(val) \ 539 do { (val)->freeswap = (val)->totalswap = 0; } while (0) 540 /* only sparc can not include linux/pagemap.h in this file 541 * so leave put_page and release_pages undeclared... */ 542 #define free_page_and_swap_cache(page) \ 543 put_page(page) 544 #define free_pages_and_swap_cache(pages, nr) \ 545 release_pages((pages), (nr)); 546 547 static inline void free_swap_and_cache_nr(swp_entry_t entry, int nr) 548 { 549 } 550 551 static inline void free_swap_cache(struct folio *folio) 552 { 553 } 554 555 static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask) 556 { 557 return 0; 558 } 559 560 static inline void swap_shmem_alloc(swp_entry_t swp, int nr) 561 { 562 } 563 564 static inline int swap_duplicate(swp_entry_t swp) 565 { 566 return 0; 567 } 568 569 static inline int swapcache_prepare(swp_entry_t swp, int nr) 570 { 571 return 0; 572 } 573 574 static inline void swap_free_nr(swp_entry_t entry, int nr_pages) 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 swap_swapcount(struct swap_info_struct *si, 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 static inline void free_swap_and_cache(swp_entry_t entry) 618 { 619 free_swap_and_cache_nr(entry, 1); 620 } 621 622 static inline void swap_free(swp_entry_t entry) 623 { 624 swap_free_nr(entry, 1); 625 } 626 627 #ifdef CONFIG_MEMCG 628 static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg) 629 { 630 /* Cgroup2 doesn't have per-cgroup swappiness */ 631 if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) 632 return READ_ONCE(vm_swappiness); 633 634 /* root ? */ 635 if (mem_cgroup_disabled() || mem_cgroup_is_root(memcg)) 636 return READ_ONCE(vm_swappiness); 637 638 return READ_ONCE(memcg->swappiness); 639 } 640 #else 641 static inline int mem_cgroup_swappiness(struct mem_cgroup *mem) 642 { 643 return READ_ONCE(vm_swappiness); 644 } 645 #endif 646 647 #if defined(CONFIG_SWAP) && defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP) 648 void __folio_throttle_swaprate(struct folio *folio, gfp_t gfp); 649 static inline void folio_throttle_swaprate(struct folio *folio, gfp_t gfp) 650 { 651 if (mem_cgroup_disabled()) 652 return; 653 __folio_throttle_swaprate(folio, gfp); 654 } 655 #else 656 static inline void folio_throttle_swaprate(struct folio *folio, gfp_t gfp) 657 { 658 } 659 #endif 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