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/atomic.h> 14 #include <linux/page-flags.h> 15 #include <asm/page.h> 16 17 struct notifier_block; 18 19 struct bio; 20 21 #define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */ 22 #define SWAP_FLAG_PRIO_MASK 0x7fff 23 #define SWAP_FLAG_PRIO_SHIFT 0 24 #define SWAP_FLAG_DISCARD 0x10000 /* enable discard for swap */ 25 #define SWAP_FLAG_DISCARD_ONCE 0x20000 /* discard swap area at swapon-time */ 26 #define SWAP_FLAG_DISCARD_PAGES 0x40000 /* discard page-clusters after use */ 27 28 #define SWAP_FLAGS_VALID (SWAP_FLAG_PRIO_MASK | SWAP_FLAG_PREFER | \ 29 SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE | \ 30 SWAP_FLAG_DISCARD_PAGES) 31 #define SWAP_BATCH 64 32 33 static inline int current_is_kswapd(void) 34 { 35 return current->flags & PF_KSWAPD; 36 } 37 38 /* 39 * MAX_SWAPFILES defines the maximum number of swaptypes: things which can 40 * be swapped to. The swap type and the offset into that swap type are 41 * encoded into pte's and into pgoff_t's in the swapcache. Using five bits 42 * for the type means that the maximum number of swapcache pages is 27 bits 43 * on 32-bit-pgoff_t architectures. And that assumes that the architecture packs 44 * the type/offset into the pte as 5/27 as well. 45 */ 46 #define MAX_SWAPFILES_SHIFT 5 47 48 /* 49 * Use some of the swap files numbers for other purposes. This 50 * is a convenient way to hook into the VM to trigger special 51 * actions on faults. 52 */ 53 54 /* 55 * Unaddressable device memory support. See include/linux/hmm.h and 56 * Documentation/vm/hmm.txt. Short description is we need struct pages for 57 * device memory that is unaddressable (inaccessible) by CPU, so that we can 58 * migrate part of a process memory to device memory. 59 * 60 * When a page is migrated from CPU to device, we set the CPU page table entry 61 * to a special SWP_DEVICE_* entry. 62 */ 63 #ifdef CONFIG_DEVICE_PRIVATE 64 #define SWP_DEVICE_NUM 2 65 #define SWP_DEVICE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM) 66 #define SWP_DEVICE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+1) 67 #else 68 #define SWP_DEVICE_NUM 0 69 #endif 70 71 /* 72 * NUMA node memory migration support 73 */ 74 #ifdef CONFIG_MIGRATION 75 #define SWP_MIGRATION_NUM 2 76 #define SWP_MIGRATION_READ (MAX_SWAPFILES + SWP_HWPOISON_NUM) 77 #define SWP_MIGRATION_WRITE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1) 78 #else 79 #define SWP_MIGRATION_NUM 0 80 #endif 81 82 /* 83 * Handling of hardware poisoned pages with memory corruption. 84 */ 85 #ifdef CONFIG_MEMORY_FAILURE 86 #define SWP_HWPOISON_NUM 1 87 #define SWP_HWPOISON MAX_SWAPFILES 88 #else 89 #define SWP_HWPOISON_NUM 0 90 #endif 91 92 #define MAX_SWAPFILES \ 93 ((1 << MAX_SWAPFILES_SHIFT) - SWP_DEVICE_NUM - \ 94 SWP_MIGRATION_NUM - SWP_HWPOISON_NUM) 95 96 /* 97 * Magic header for a swap area. The first part of the union is 98 * what the swap magic looks like for the old (limited to 128MB) 99 * swap area format, the second part of the union adds - in the 100 * old reserved area - some extra information. Note that the first 101 * kilobyte is reserved for boot loader or disk label stuff... 102 * 103 * Having the magic at the end of the PAGE_SIZE makes detecting swap 104 * areas somewhat tricky on machines that support multiple page sizes. 105 * For 2.5 we'll probably want to move the magic to just beyond the 106 * bootbits... 107 */ 108 union swap_header { 109 struct { 110 char reserved[PAGE_SIZE - 10]; 111 char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */ 112 } magic; 113 struct { 114 char bootbits[1024]; /* Space for disklabel etc. */ 115 __u32 version; 116 __u32 last_page; 117 __u32 nr_badpages; 118 unsigned char sws_uuid[16]; 119 unsigned char sws_volume[16]; 120 __u32 padding[117]; 121 __u32 badpages[1]; 122 } info; 123 }; 124 125 /* 126 * current->reclaim_state points to one of these when a task is running 127 * memory reclaim 128 */ 129 struct reclaim_state { 130 unsigned long reclaimed_slab; 131 }; 132 133 #ifdef __KERNEL__ 134 135 struct address_space; 136 struct sysinfo; 137 struct writeback_control; 138 struct zone; 139 140 /* 141 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of 142 * disk blocks. A list of swap extents maps the entire swapfile. (Where the 143 * term `swapfile' refers to either a blockdevice or an IS_REG file. Apart 144 * from setup, they're handled identically. 145 * 146 * We always assume that blocks are of size PAGE_SIZE. 147 */ 148 struct swap_extent { 149 struct list_head list; 150 pgoff_t start_page; 151 pgoff_t nr_pages; 152 sector_t start_block; 153 }; 154 155 /* 156 * Max bad pages in the new format.. 157 */ 158 #define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x) 159 #define MAX_SWAP_BADPAGES \ 160 ((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int)) 161 162 enum { 163 SWP_USED = (1 << 0), /* is slot in swap_info[] used? */ 164 SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */ 165 SWP_DISCARDABLE = (1 << 2), /* blkdev support discard */ 166 SWP_DISCARDING = (1 << 3), /* now discarding a free cluster */ 167 SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */ 168 SWP_CONTINUED = (1 << 5), /* swap_map has count continuation */ 169 SWP_BLKDEV = (1 << 6), /* its a block device */ 170 SWP_FILE = (1 << 7), /* set after swap_activate success */ 171 SWP_AREA_DISCARD = (1 << 8), /* single-time swap area discards */ 172 SWP_PAGE_DISCARD = (1 << 9), /* freed swap page-cluster discards */ 173 SWP_STABLE_WRITES = (1 << 10), /* no overwrite PG_writeback pages */ 174 SWP_SYNCHRONOUS_IO = (1 << 11), /* synchronous IO is efficient */ 175 /* add others here before... */ 176 SWP_SCANNING = (1 << 12), /* refcount in scan_swap_map */ 177 }; 178 179 #define SWAP_CLUSTER_MAX 32UL 180 #define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX 181 182 #define SWAP_MAP_MAX 0x3e /* Max duplication count, in first swap_map */ 183 #define SWAP_MAP_BAD 0x3f /* Note pageblock is bad, in first swap_map */ 184 #define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */ 185 #define SWAP_CONT_MAX 0x7f /* Max count, in each swap_map continuation */ 186 #define COUNT_CONTINUED 0x80 /* See swap_map continuation for full count */ 187 #define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs, in first swap_map */ 188 189 /* 190 * We use this to track usage of a cluster. A cluster is a block of swap disk 191 * space with SWAPFILE_CLUSTER pages long and naturally aligns in disk. All 192 * free clusters are organized into a list. We fetch an entry from the list to 193 * get a free cluster. 194 * 195 * The data field stores next cluster if the cluster is free or cluster usage 196 * counter otherwise. The flags field determines if a cluster is free. This is 197 * protected by swap_info_struct.lock. 198 */ 199 struct swap_cluster_info { 200 spinlock_t lock; /* 201 * Protect swap_cluster_info fields 202 * and swap_info_struct->swap_map 203 * elements correspond to the swap 204 * cluster 205 */ 206 unsigned int data:24; 207 unsigned int flags:8; 208 }; 209 #define CLUSTER_FLAG_FREE 1 /* This cluster is free */ 210 #define CLUSTER_FLAG_NEXT_NULL 2 /* This cluster has no next cluster */ 211 #define CLUSTER_FLAG_HUGE 4 /* This cluster is backing a transparent huge page */ 212 213 /* 214 * We assign a cluster to each CPU, so each CPU can allocate swap entry from 215 * its own cluster and swapout sequentially. The purpose is to optimize swapout 216 * throughput. 217 */ 218 struct percpu_cluster { 219 struct swap_cluster_info index; /* Current cluster index */ 220 unsigned int next; /* Likely next allocation offset */ 221 }; 222 223 struct swap_cluster_list { 224 struct swap_cluster_info head; 225 struct swap_cluster_info tail; 226 }; 227 228 /* 229 * The in-memory structure used to track swap areas. 230 */ 231 struct swap_info_struct { 232 unsigned long flags; /* SWP_USED etc: see above */ 233 signed short prio; /* swap priority of this type */ 234 struct plist_node list; /* entry in swap_active_head */ 235 struct plist_node avail_lists[MAX_NUMNODES];/* entry in swap_avail_heads */ 236 signed char type; /* strange name for an index */ 237 unsigned int max; /* extent of the swap_map */ 238 unsigned char *swap_map; /* vmalloc'ed array of usage counts */ 239 struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */ 240 struct swap_cluster_list free_clusters; /* free clusters list */ 241 unsigned int lowest_bit; /* index of first free in swap_map */ 242 unsigned int highest_bit; /* index of last free in swap_map */ 243 unsigned int pages; /* total of usable pages of swap */ 244 unsigned int inuse_pages; /* number of those currently in use */ 245 unsigned int cluster_next; /* likely index for next allocation */ 246 unsigned int cluster_nr; /* countdown to next cluster search */ 247 struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */ 248 struct swap_extent *curr_swap_extent; 249 struct swap_extent first_swap_extent; 250 struct block_device *bdev; /* swap device or bdev of swap file */ 251 struct file *swap_file; /* seldom referenced */ 252 unsigned int old_block_size; /* seldom referenced */ 253 #ifdef CONFIG_FRONTSWAP 254 unsigned long *frontswap_map; /* frontswap in-use, one bit per page */ 255 atomic_t frontswap_pages; /* frontswap pages in-use counter */ 256 #endif 257 spinlock_t lock; /* 258 * protect map scan related fields like 259 * swap_map, lowest_bit, highest_bit, 260 * inuse_pages, cluster_next, 261 * cluster_nr, lowest_alloc, 262 * highest_alloc, free/discard cluster 263 * list. other fields are only changed 264 * at swapon/swapoff, so are protected 265 * by swap_lock. changing flags need 266 * hold this lock and swap_lock. If 267 * both locks need hold, hold swap_lock 268 * first. 269 */ 270 spinlock_t cont_lock; /* 271 * protect swap count continuation page 272 * list. 273 */ 274 struct work_struct discard_work; /* discard worker */ 275 struct swap_cluster_list discard_clusters; /* discard clusters list */ 276 }; 277 278 #ifdef CONFIG_64BIT 279 #define SWAP_RA_ORDER_CEILING 5 280 #else 281 /* Avoid stack overflow, because we need to save part of page table */ 282 #define SWAP_RA_ORDER_CEILING 3 283 #define SWAP_RA_PTE_CACHE_SIZE (1 << SWAP_RA_ORDER_CEILING) 284 #endif 285 286 struct vma_swap_readahead { 287 unsigned short win; 288 unsigned short offset; 289 unsigned short nr_pte; 290 #ifdef CONFIG_64BIT 291 pte_t *ptes; 292 #else 293 pte_t ptes[SWAP_RA_PTE_CACHE_SIZE]; 294 #endif 295 }; 296 297 /* linux/mm/workingset.c */ 298 void *workingset_eviction(struct address_space *mapping, struct page *page); 299 bool workingset_refault(void *shadow); 300 void workingset_activation(struct page *page); 301 302 /* Do not use directly, use workingset_lookup_update */ 303 void workingset_update_node(struct radix_tree_node *node); 304 305 /* Returns workingset_update_node() if the mapping has shadow entries. */ 306 #define workingset_lookup_update(mapping) \ 307 ({ \ 308 radix_tree_update_node_t __helper = workingset_update_node; \ 309 if (dax_mapping(mapping) || shmem_mapping(mapping)) \ 310 __helper = NULL; \ 311 __helper; \ 312 }) 313 314 /* linux/mm/page_alloc.c */ 315 extern unsigned long totalram_pages; 316 extern unsigned long totalreserve_pages; 317 extern unsigned long nr_free_buffer_pages(void); 318 extern unsigned long nr_free_pagecache_pages(void); 319 320 /* Definition of global_zone_page_state not available yet */ 321 #define nr_free_pages() global_zone_page_state(NR_FREE_PAGES) 322 323 324 /* linux/mm/swap.c */ 325 extern void lru_cache_add(struct page *); 326 extern void lru_cache_add_anon(struct page *page); 327 extern void lru_cache_add_file(struct page *page); 328 extern void lru_add_page_tail(struct page *page, struct page *page_tail, 329 struct lruvec *lruvec, struct list_head *head); 330 extern void activate_page(struct page *); 331 extern void mark_page_accessed(struct page *); 332 extern void lru_add_drain(void); 333 extern void lru_add_drain_cpu(int cpu); 334 extern void lru_add_drain_all(void); 335 extern void rotate_reclaimable_page(struct page *page); 336 extern void deactivate_file_page(struct page *page); 337 extern void mark_page_lazyfree(struct page *page); 338 extern void swap_setup(void); 339 340 extern void lru_cache_add_active_or_unevictable(struct page *page, 341 struct vm_area_struct *vma); 342 343 /* linux/mm/vmscan.c */ 344 extern unsigned long zone_reclaimable_pages(struct zone *zone); 345 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order, 346 gfp_t gfp_mask, nodemask_t *mask); 347 extern int __isolate_lru_page(struct page *page, isolate_mode_t mode); 348 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg, 349 unsigned long nr_pages, 350 gfp_t gfp_mask, 351 bool may_swap); 352 extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem, 353 gfp_t gfp_mask, bool noswap, 354 pg_data_t *pgdat, 355 unsigned long *nr_scanned); 356 extern unsigned long shrink_all_memory(unsigned long nr_pages); 357 extern int vm_swappiness; 358 extern int remove_mapping(struct address_space *mapping, struct page *page); 359 extern unsigned long vm_total_pages; 360 361 #ifdef CONFIG_NUMA 362 extern int node_reclaim_mode; 363 extern int sysctl_min_unmapped_ratio; 364 extern int sysctl_min_slab_ratio; 365 extern int node_reclaim(struct pglist_data *, gfp_t, unsigned int); 366 #else 367 #define node_reclaim_mode 0 368 static inline int node_reclaim(struct pglist_data *pgdat, gfp_t mask, 369 unsigned int order) 370 { 371 return 0; 372 } 373 #endif 374 375 extern int page_evictable(struct page *page); 376 extern void check_move_unevictable_pages(struct page **, int nr_pages); 377 378 extern int kswapd_run(int nid); 379 extern void kswapd_stop(int nid); 380 381 #ifdef CONFIG_SWAP 382 383 #include <linux/blk_types.h> /* for bio_end_io_t */ 384 385 /* linux/mm/page_io.c */ 386 extern int swap_readpage(struct page *page, bool do_poll); 387 extern int swap_writepage(struct page *page, struct writeback_control *wbc); 388 extern void end_swap_bio_write(struct bio *bio); 389 extern int __swap_writepage(struct page *page, struct writeback_control *wbc, 390 bio_end_io_t end_write_func); 391 extern int swap_set_page_dirty(struct page *page); 392 393 int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, 394 unsigned long nr_pages, sector_t start_block); 395 int generic_swapfile_activate(struct swap_info_struct *, struct file *, 396 sector_t *); 397 398 /* linux/mm/swap_state.c */ 399 /* One swap address space for each 64M swap space */ 400 #define SWAP_ADDRESS_SPACE_SHIFT 14 401 #define SWAP_ADDRESS_SPACE_PAGES (1 << SWAP_ADDRESS_SPACE_SHIFT) 402 extern struct address_space *swapper_spaces[]; 403 #define swap_address_space(entry) \ 404 (&swapper_spaces[swp_type(entry)][swp_offset(entry) \ 405 >> SWAP_ADDRESS_SPACE_SHIFT]) 406 extern unsigned long total_swapcache_pages(void); 407 extern void show_swap_cache_info(void); 408 extern int add_to_swap(struct page *page); 409 extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t); 410 extern int __add_to_swap_cache(struct page *page, swp_entry_t entry); 411 extern void __delete_from_swap_cache(struct page *); 412 extern void delete_from_swap_cache(struct page *); 413 extern void free_page_and_swap_cache(struct page *); 414 extern void free_pages_and_swap_cache(struct page **, int); 415 extern struct page *lookup_swap_cache(swp_entry_t entry, 416 struct vm_area_struct *vma, 417 unsigned long addr); 418 extern struct page *read_swap_cache_async(swp_entry_t, gfp_t, 419 struct vm_area_struct *vma, unsigned long addr, 420 bool do_poll); 421 extern struct page *__read_swap_cache_async(swp_entry_t, gfp_t, 422 struct vm_area_struct *vma, unsigned long addr, 423 bool *new_page_allocated); 424 extern struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t flag, 425 struct vm_fault *vmf); 426 extern struct page *swapin_readahead(swp_entry_t entry, gfp_t flag, 427 struct vm_fault *vmf); 428 429 /* linux/mm/swapfile.c */ 430 extern atomic_long_t nr_swap_pages; 431 extern long total_swap_pages; 432 extern atomic_t nr_rotate_swap; 433 extern bool has_usable_swap(void); 434 435 /* Swap 50% full? Release swapcache more aggressively.. */ 436 static inline bool vm_swap_full(void) 437 { 438 return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages; 439 } 440 441 static inline long get_nr_swap_pages(void) 442 { 443 return atomic_long_read(&nr_swap_pages); 444 } 445 446 extern void si_swapinfo(struct sysinfo *); 447 extern swp_entry_t get_swap_page(struct page *page); 448 extern void put_swap_page(struct page *page, swp_entry_t entry); 449 extern swp_entry_t get_swap_page_of_type(int); 450 extern int get_swap_pages(int n, bool cluster, swp_entry_t swp_entries[]); 451 extern int add_swap_count_continuation(swp_entry_t, gfp_t); 452 extern void swap_shmem_alloc(swp_entry_t); 453 extern int swap_duplicate(swp_entry_t); 454 extern int swapcache_prepare(swp_entry_t); 455 extern void swap_free(swp_entry_t); 456 extern void swapcache_free_entries(swp_entry_t *entries, int n); 457 extern int free_swap_and_cache(swp_entry_t); 458 extern int swap_type_of(dev_t, sector_t, struct block_device **); 459 extern unsigned int count_swap_pages(int, int); 460 extern sector_t map_swap_page(struct page *, struct block_device **); 461 extern sector_t swapdev_block(int, pgoff_t); 462 extern int page_swapcount(struct page *); 463 extern int __swap_count(struct swap_info_struct *si, swp_entry_t entry); 464 extern int __swp_swapcount(swp_entry_t entry); 465 extern int swp_swapcount(swp_entry_t entry); 466 extern struct swap_info_struct *page_swap_info(struct page *); 467 extern struct swap_info_struct *swp_swap_info(swp_entry_t entry); 468 extern bool reuse_swap_page(struct page *, int *); 469 extern int try_to_free_swap(struct page *); 470 struct backing_dev_info; 471 extern int init_swap_address_space(unsigned int type, unsigned long nr_pages); 472 extern void exit_swap_address_space(unsigned int type); 473 474 #else /* CONFIG_SWAP */ 475 476 static inline int swap_readpage(struct page *page, bool do_poll) 477 { 478 return 0; 479 } 480 481 static inline struct swap_info_struct *swp_swap_info(swp_entry_t entry) 482 { 483 return NULL; 484 } 485 486 #define swap_address_space(entry) (NULL) 487 #define get_nr_swap_pages() 0L 488 #define total_swap_pages 0L 489 #define total_swapcache_pages() 0UL 490 #define vm_swap_full() 0 491 492 #define si_swapinfo(val) \ 493 do { (val)->freeswap = (val)->totalswap = 0; } while (0) 494 /* only sparc can not include linux/pagemap.h in this file 495 * so leave put_page and release_pages undeclared... */ 496 #define free_page_and_swap_cache(page) \ 497 put_page(page) 498 #define free_pages_and_swap_cache(pages, nr) \ 499 release_pages((pages), (nr)); 500 501 static inline void show_swap_cache_info(void) 502 { 503 } 504 505 #define free_swap_and_cache(e) ({(is_migration_entry(e) || is_device_private_entry(e));}) 506 #define swapcache_prepare(e) ({(is_migration_entry(e) || is_device_private_entry(e));}) 507 508 static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask) 509 { 510 return 0; 511 } 512 513 static inline void swap_shmem_alloc(swp_entry_t swp) 514 { 515 } 516 517 static inline int swap_duplicate(swp_entry_t swp) 518 { 519 return 0; 520 } 521 522 static inline void swap_free(swp_entry_t swp) 523 { 524 } 525 526 static inline void put_swap_page(struct page *page, swp_entry_t swp) 527 { 528 } 529 530 static inline struct page *swap_cluster_readahead(swp_entry_t entry, 531 gfp_t gfp_mask, struct vm_fault *vmf) 532 { 533 return NULL; 534 } 535 536 static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask, 537 struct vm_fault *vmf) 538 { 539 return NULL; 540 } 541 542 static inline int swap_writepage(struct page *p, struct writeback_control *wbc) 543 { 544 return 0; 545 } 546 547 static inline struct page *lookup_swap_cache(swp_entry_t swp, 548 struct vm_area_struct *vma, 549 unsigned long addr) 550 { 551 return NULL; 552 } 553 554 static inline int add_to_swap(struct page *page) 555 { 556 return 0; 557 } 558 559 static inline int add_to_swap_cache(struct page *page, swp_entry_t entry, 560 gfp_t gfp_mask) 561 { 562 return -1; 563 } 564 565 static inline void __delete_from_swap_cache(struct page *page) 566 { 567 } 568 569 static inline void delete_from_swap_cache(struct page *page) 570 { 571 } 572 573 static inline int page_swapcount(struct page *page) 574 { 575 return 0; 576 } 577 578 static inline int __swap_count(struct swap_info_struct *si, swp_entry_t entry) 579 { 580 return 0; 581 } 582 583 static inline int __swp_swapcount(swp_entry_t entry) 584 { 585 return 0; 586 } 587 588 static inline int swp_swapcount(swp_entry_t entry) 589 { 590 return 0; 591 } 592 593 #define reuse_swap_page(page, total_map_swapcount) \ 594 (page_trans_huge_mapcount(page, total_map_swapcount) == 1) 595 596 static inline int try_to_free_swap(struct page *page) 597 { 598 return 0; 599 } 600 601 static inline swp_entry_t get_swap_page(struct page *page) 602 { 603 swp_entry_t entry; 604 entry.val = 0; 605 return entry; 606 } 607 608 #endif /* CONFIG_SWAP */ 609 610 #ifdef CONFIG_THP_SWAP 611 extern int split_swap_cluster(swp_entry_t entry); 612 #else 613 static inline int split_swap_cluster(swp_entry_t entry) 614 { 615 return 0; 616 } 617 #endif 618 619 #ifdef CONFIG_MEMCG 620 static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg) 621 { 622 /* Cgroup2 doesn't have per-cgroup swappiness */ 623 if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) 624 return vm_swappiness; 625 626 /* root ? */ 627 if (mem_cgroup_disabled() || !memcg->css.parent) 628 return vm_swappiness; 629 630 return memcg->swappiness; 631 } 632 633 #else 634 static inline int mem_cgroup_swappiness(struct mem_cgroup *mem) 635 { 636 return vm_swappiness; 637 } 638 #endif 639 640 #ifdef CONFIG_MEMCG_SWAP 641 extern void mem_cgroup_swapout(struct page *page, swp_entry_t entry); 642 extern int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry); 643 extern void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages); 644 extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg); 645 extern bool mem_cgroup_swap_full(struct page *page); 646 #else 647 static inline void mem_cgroup_swapout(struct page *page, swp_entry_t entry) 648 { 649 } 650 651 static inline int mem_cgroup_try_charge_swap(struct page *page, 652 swp_entry_t entry) 653 { 654 return 0; 655 } 656 657 static inline void mem_cgroup_uncharge_swap(swp_entry_t entry, 658 unsigned int nr_pages) 659 { 660 } 661 662 static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg) 663 { 664 return get_nr_swap_pages(); 665 } 666 667 static inline bool mem_cgroup_swap_full(struct page *page) 668 { 669 return vm_swap_full(); 670 } 671 #endif 672 673 #endif /* __KERNEL__*/ 674 #endif /* _LINUX_SWAP_H */ 675