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 /* add others here before... */ 175 SWP_SCANNING = (1 << 11), /* refcount in scan_swap_map */ 176 }; 177 178 #define SWAP_CLUSTER_MAX 32UL 179 #define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX 180 181 #define SWAP_MAP_MAX 0x3e /* Max duplication count, in first swap_map */ 182 #define SWAP_MAP_BAD 0x3f /* Note pageblock is bad, in first swap_map */ 183 #define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */ 184 #define SWAP_CONT_MAX 0x7f /* Max count, in each swap_map continuation */ 185 #define COUNT_CONTINUED 0x80 /* See swap_map continuation for full count */ 186 #define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs, in first swap_map */ 187 188 /* 189 * We use this to track usage of a cluster. A cluster is a block of swap disk 190 * space with SWAPFILE_CLUSTER pages long and naturally aligns in disk. All 191 * free clusters are organized into a list. We fetch an entry from the list to 192 * get a free cluster. 193 * 194 * The data field stores next cluster if the cluster is free or cluster usage 195 * counter otherwise. The flags field determines if a cluster is free. This is 196 * protected by swap_info_struct.lock. 197 */ 198 struct swap_cluster_info { 199 spinlock_t lock; /* 200 * Protect swap_cluster_info fields 201 * and swap_info_struct->swap_map 202 * elements correspond to the swap 203 * cluster 204 */ 205 unsigned int data:24; 206 unsigned int flags:8; 207 }; 208 #define CLUSTER_FLAG_FREE 1 /* This cluster is free */ 209 #define CLUSTER_FLAG_NEXT_NULL 2 /* This cluster has no next cluster */ 210 #define CLUSTER_FLAG_HUGE 4 /* This cluster is backing a transparent huge page */ 211 212 /* 213 * We assign a cluster to each CPU, so each CPU can allocate swap entry from 214 * its own cluster and swapout sequentially. The purpose is to optimize swapout 215 * throughput. 216 */ 217 struct percpu_cluster { 218 struct swap_cluster_info index; /* Current cluster index */ 219 unsigned int next; /* Likely next allocation offset */ 220 }; 221 222 struct swap_cluster_list { 223 struct swap_cluster_info head; 224 struct swap_cluster_info tail; 225 }; 226 227 /* 228 * The in-memory structure used to track swap areas. 229 */ 230 struct swap_info_struct { 231 unsigned long flags; /* SWP_USED etc: see above */ 232 signed short prio; /* swap priority of this type */ 233 struct plist_node list; /* entry in swap_active_head */ 234 struct plist_node avail_lists[MAX_NUMNODES];/* entry in swap_avail_heads */ 235 signed char type; /* strange name for an index */ 236 unsigned int max; /* extent of the swap_map */ 237 unsigned char *swap_map; /* vmalloc'ed array of usage counts */ 238 struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */ 239 struct swap_cluster_list free_clusters; /* free clusters list */ 240 unsigned int lowest_bit; /* index of first free in swap_map */ 241 unsigned int highest_bit; /* index of last free in swap_map */ 242 unsigned int pages; /* total of usable pages of swap */ 243 unsigned int inuse_pages; /* number of those currently in use */ 244 unsigned int cluster_next; /* likely index for next allocation */ 245 unsigned int cluster_nr; /* countdown to next cluster search */ 246 struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */ 247 struct swap_extent *curr_swap_extent; 248 struct swap_extent first_swap_extent; 249 struct block_device *bdev; /* swap device or bdev of swap file */ 250 struct file *swap_file; /* seldom referenced */ 251 unsigned int old_block_size; /* seldom referenced */ 252 #ifdef CONFIG_FRONTSWAP 253 unsigned long *frontswap_map; /* frontswap in-use, one bit per page */ 254 atomic_t frontswap_pages; /* frontswap pages in-use counter */ 255 #endif 256 spinlock_t lock; /* 257 * protect map scan related fields like 258 * swap_map, lowest_bit, highest_bit, 259 * inuse_pages, cluster_next, 260 * cluster_nr, lowest_alloc, 261 * highest_alloc, free/discard cluster 262 * list. other fields are only changed 263 * at swapon/swapoff, so are protected 264 * by swap_lock. changing flags need 265 * hold this lock and swap_lock. If 266 * both locks need hold, hold swap_lock 267 * first. 268 */ 269 spinlock_t cont_lock; /* 270 * protect swap count continuation page 271 * list. 272 */ 273 struct work_struct discard_work; /* discard worker */ 274 struct swap_cluster_list discard_clusters; /* discard clusters list */ 275 }; 276 277 #ifdef CONFIG_64BIT 278 #define SWAP_RA_ORDER_CEILING 5 279 #else 280 /* Avoid stack overflow, because we need to save part of page table */ 281 #define SWAP_RA_ORDER_CEILING 3 282 #define SWAP_RA_PTE_CACHE_SIZE (1 << SWAP_RA_ORDER_CEILING) 283 #endif 284 285 struct vma_swap_readahead { 286 unsigned short win; 287 unsigned short offset; 288 unsigned short nr_pte; 289 #ifdef CONFIG_64BIT 290 pte_t *ptes; 291 #else 292 pte_t ptes[SWAP_RA_PTE_CACHE_SIZE]; 293 #endif 294 }; 295 296 /* linux/mm/workingset.c */ 297 void *workingset_eviction(struct address_space *mapping, struct page *page); 298 bool workingset_refault(void *shadow); 299 void workingset_activation(struct page *page); 300 void workingset_update_node(struct radix_tree_node *node, void *private); 301 302 /* linux/mm/page_alloc.c */ 303 extern unsigned long totalram_pages; 304 extern unsigned long totalreserve_pages; 305 extern unsigned long nr_free_buffer_pages(void); 306 extern unsigned long nr_free_pagecache_pages(void); 307 308 /* Definition of global_zone_page_state not available yet */ 309 #define nr_free_pages() global_zone_page_state(NR_FREE_PAGES) 310 311 312 /* linux/mm/swap.c */ 313 extern void lru_cache_add(struct page *); 314 extern void lru_cache_add_anon(struct page *page); 315 extern void lru_cache_add_file(struct page *page); 316 extern void lru_add_page_tail(struct page *page, struct page *page_tail, 317 struct lruvec *lruvec, struct list_head *head); 318 extern void activate_page(struct page *); 319 extern void mark_page_accessed(struct page *); 320 extern void lru_add_drain(void); 321 extern void lru_add_drain_cpu(int cpu); 322 extern void lru_add_drain_all(void); 323 extern void lru_add_drain_all_cpuslocked(void); 324 extern void rotate_reclaimable_page(struct page *page); 325 extern void deactivate_file_page(struct page *page); 326 extern void mark_page_lazyfree(struct page *page); 327 extern void swap_setup(void); 328 329 extern void add_page_to_unevictable_list(struct page *page); 330 331 extern void lru_cache_add_active_or_unevictable(struct page *page, 332 struct vm_area_struct *vma); 333 334 /* linux/mm/vmscan.c */ 335 extern unsigned long zone_reclaimable_pages(struct zone *zone); 336 extern unsigned long pgdat_reclaimable_pages(struct pglist_data *pgdat); 337 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order, 338 gfp_t gfp_mask, nodemask_t *mask); 339 extern int __isolate_lru_page(struct page *page, isolate_mode_t mode); 340 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg, 341 unsigned long nr_pages, 342 gfp_t gfp_mask, 343 bool may_swap); 344 extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem, 345 gfp_t gfp_mask, bool noswap, 346 pg_data_t *pgdat, 347 unsigned long *nr_scanned); 348 extern unsigned long shrink_all_memory(unsigned long nr_pages); 349 extern int vm_swappiness; 350 extern int remove_mapping(struct address_space *mapping, struct page *page); 351 extern unsigned long vm_total_pages; 352 353 #ifdef CONFIG_NUMA 354 extern int node_reclaim_mode; 355 extern int sysctl_min_unmapped_ratio; 356 extern int sysctl_min_slab_ratio; 357 extern int node_reclaim(struct pglist_data *, gfp_t, unsigned int); 358 #else 359 #define node_reclaim_mode 0 360 static inline int node_reclaim(struct pglist_data *pgdat, gfp_t mask, 361 unsigned int order) 362 { 363 return 0; 364 } 365 #endif 366 367 extern int page_evictable(struct page *page); 368 extern void check_move_unevictable_pages(struct page **, int nr_pages); 369 370 extern int kswapd_run(int nid); 371 extern void kswapd_stop(int nid); 372 373 #ifdef CONFIG_SWAP 374 375 #include <linux/blk_types.h> /* for bio_end_io_t */ 376 377 /* linux/mm/page_io.c */ 378 extern int swap_readpage(struct page *page, bool do_poll); 379 extern int swap_writepage(struct page *page, struct writeback_control *wbc); 380 extern void end_swap_bio_write(struct bio *bio); 381 extern int __swap_writepage(struct page *page, struct writeback_control *wbc, 382 bio_end_io_t end_write_func); 383 extern int swap_set_page_dirty(struct page *page); 384 385 int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, 386 unsigned long nr_pages, sector_t start_block); 387 int generic_swapfile_activate(struct swap_info_struct *, struct file *, 388 sector_t *); 389 390 /* linux/mm/swap_state.c */ 391 /* One swap address space for each 64M swap space */ 392 #define SWAP_ADDRESS_SPACE_SHIFT 14 393 #define SWAP_ADDRESS_SPACE_PAGES (1 << SWAP_ADDRESS_SPACE_SHIFT) 394 extern struct address_space *swapper_spaces[]; 395 extern bool swap_vma_readahead; 396 #define swap_address_space(entry) \ 397 (&swapper_spaces[swp_type(entry)][swp_offset(entry) \ 398 >> SWAP_ADDRESS_SPACE_SHIFT]) 399 extern unsigned long total_swapcache_pages(void); 400 extern void show_swap_cache_info(void); 401 extern int add_to_swap(struct page *page); 402 extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t); 403 extern int __add_to_swap_cache(struct page *page, swp_entry_t entry); 404 extern void __delete_from_swap_cache(struct page *); 405 extern void delete_from_swap_cache(struct page *); 406 extern void free_page_and_swap_cache(struct page *); 407 extern void free_pages_and_swap_cache(struct page **, int); 408 extern struct page *lookup_swap_cache(swp_entry_t entry, 409 struct vm_area_struct *vma, 410 unsigned long addr); 411 extern struct page *read_swap_cache_async(swp_entry_t, gfp_t, 412 struct vm_area_struct *vma, unsigned long addr, 413 bool do_poll); 414 extern struct page *__read_swap_cache_async(swp_entry_t, gfp_t, 415 struct vm_area_struct *vma, unsigned long addr, 416 bool *new_page_allocated); 417 extern struct page *swapin_readahead(swp_entry_t, gfp_t, 418 struct vm_area_struct *vma, unsigned long addr); 419 420 extern struct page *swap_readahead_detect(struct vm_fault *vmf, 421 struct vma_swap_readahead *swap_ra); 422 extern struct page *do_swap_page_readahead(swp_entry_t fentry, gfp_t gfp_mask, 423 struct vm_fault *vmf, 424 struct vma_swap_readahead *swap_ra); 425 426 /* linux/mm/swapfile.c */ 427 extern atomic_long_t nr_swap_pages; 428 extern long total_swap_pages; 429 extern atomic_t nr_rotate_swap; 430 extern bool has_usable_swap(void); 431 432 static inline bool swap_use_vma_readahead(void) 433 { 434 return READ_ONCE(swap_vma_readahead) && !atomic_read(&nr_rotate_swap); 435 } 436 437 /* Swap 50% full? Release swapcache more aggressively.. */ 438 static inline bool vm_swap_full(void) 439 { 440 return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages; 441 } 442 443 static inline long get_nr_swap_pages(void) 444 { 445 return atomic_long_read(&nr_swap_pages); 446 } 447 448 extern void si_swapinfo(struct sysinfo *); 449 extern swp_entry_t get_swap_page(struct page *page); 450 extern void put_swap_page(struct page *page, swp_entry_t entry); 451 extern swp_entry_t get_swap_page_of_type(int); 452 extern int get_swap_pages(int n, bool cluster, swp_entry_t swp_entries[]); 453 extern int add_swap_count_continuation(swp_entry_t, gfp_t); 454 extern void swap_shmem_alloc(swp_entry_t); 455 extern int swap_duplicate(swp_entry_t); 456 extern int swapcache_prepare(swp_entry_t); 457 extern void swap_free(swp_entry_t); 458 extern void swapcache_free_entries(swp_entry_t *entries, int n); 459 extern int free_swap_and_cache(swp_entry_t); 460 extern int swap_type_of(dev_t, sector_t, struct block_device **); 461 extern unsigned int count_swap_pages(int, int); 462 extern sector_t map_swap_page(struct page *, struct block_device **); 463 extern sector_t swapdev_block(int, pgoff_t); 464 extern int page_swapcount(struct page *); 465 extern int __swp_swapcount(swp_entry_t entry); 466 extern int swp_swapcount(swp_entry_t entry); 467 extern struct swap_info_struct *page_swap_info(struct page *); 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 #define swap_address_space(entry) (NULL) 477 #define get_nr_swap_pages() 0L 478 #define total_swap_pages 0L 479 #define total_swapcache_pages() 0UL 480 #define vm_swap_full() 0 481 482 #define si_swapinfo(val) \ 483 do { (val)->freeswap = (val)->totalswap = 0; } while (0) 484 /* only sparc can not include linux/pagemap.h in this file 485 * so leave put_page and release_pages undeclared... */ 486 #define free_page_and_swap_cache(page) \ 487 put_page(page) 488 #define free_pages_and_swap_cache(pages, nr) \ 489 release_pages((pages), (nr), false); 490 491 static inline void show_swap_cache_info(void) 492 { 493 } 494 495 #define free_swap_and_cache(e) ({(is_migration_entry(e) || is_device_private_entry(e));}) 496 #define swapcache_prepare(e) ({(is_migration_entry(e) || is_device_private_entry(e));}) 497 498 static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask) 499 { 500 return 0; 501 } 502 503 static inline void swap_shmem_alloc(swp_entry_t swp) 504 { 505 } 506 507 static inline int swap_duplicate(swp_entry_t swp) 508 { 509 return 0; 510 } 511 512 static inline void swap_free(swp_entry_t swp) 513 { 514 } 515 516 static inline void put_swap_page(struct page *page, swp_entry_t swp) 517 { 518 } 519 520 static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask, 521 struct vm_area_struct *vma, unsigned long addr) 522 { 523 return NULL; 524 } 525 526 static inline bool swap_use_vma_readahead(void) 527 { 528 return false; 529 } 530 531 static inline struct page *swap_readahead_detect( 532 struct vm_fault *vmf, struct vma_swap_readahead *swap_ra) 533 { 534 return NULL; 535 } 536 537 static inline struct page *do_swap_page_readahead( 538 swp_entry_t fentry, gfp_t gfp_mask, 539 struct vm_fault *vmf, struct vma_swap_readahead *swap_ra) 540 { 541 return NULL; 542 } 543 544 static inline int swap_writepage(struct page *p, struct writeback_control *wbc) 545 { 546 return 0; 547 } 548 549 static inline struct page *lookup_swap_cache(swp_entry_t swp, 550 struct vm_area_struct *vma, 551 unsigned long addr) 552 { 553 return NULL; 554 } 555 556 static inline int add_to_swap(struct page *page) 557 { 558 return 0; 559 } 560 561 static inline int add_to_swap_cache(struct page *page, swp_entry_t entry, 562 gfp_t gfp_mask) 563 { 564 return -1; 565 } 566 567 static inline void __delete_from_swap_cache(struct page *page) 568 { 569 } 570 571 static inline void delete_from_swap_cache(struct page *page) 572 { 573 } 574 575 static inline int page_swapcount(struct page *page) 576 { 577 return 0; 578 } 579 580 static inline int __swp_swapcount(swp_entry_t entry) 581 { 582 return 0; 583 } 584 585 static inline int swp_swapcount(swp_entry_t entry) 586 { 587 return 0; 588 } 589 590 #define reuse_swap_page(page, total_map_swapcount) \ 591 (page_trans_huge_mapcount(page, total_map_swapcount) == 1) 592 593 static inline int try_to_free_swap(struct page *page) 594 { 595 return 0; 596 } 597 598 static inline swp_entry_t get_swap_page(struct page *page) 599 { 600 swp_entry_t entry; 601 entry.val = 0; 602 return entry; 603 } 604 605 #endif /* CONFIG_SWAP */ 606 607 #ifdef CONFIG_THP_SWAP 608 extern int split_swap_cluster(swp_entry_t entry); 609 #else 610 static inline int split_swap_cluster(swp_entry_t entry) 611 { 612 return 0; 613 } 614 #endif 615 616 #ifdef CONFIG_MEMCG 617 static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg) 618 { 619 /* Cgroup2 doesn't have per-cgroup swappiness */ 620 if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) 621 return vm_swappiness; 622 623 /* root ? */ 624 if (mem_cgroup_disabled() || !memcg->css.parent) 625 return vm_swappiness; 626 627 return memcg->swappiness; 628 } 629 630 #else 631 static inline int mem_cgroup_swappiness(struct mem_cgroup *mem) 632 { 633 return vm_swappiness; 634 } 635 #endif 636 637 #ifdef CONFIG_MEMCG_SWAP 638 extern void mem_cgroup_swapout(struct page *page, swp_entry_t entry); 639 extern int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry); 640 extern void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages); 641 extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg); 642 extern bool mem_cgroup_swap_full(struct page *page); 643 #else 644 static inline void mem_cgroup_swapout(struct page *page, swp_entry_t entry) 645 { 646 } 647 648 static inline int mem_cgroup_try_charge_swap(struct page *page, 649 swp_entry_t entry) 650 { 651 return 0; 652 } 653 654 static inline void mem_cgroup_uncharge_swap(swp_entry_t entry, 655 unsigned int nr_pages) 656 { 657 } 658 659 static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg) 660 { 661 return get_nr_swap_pages(); 662 } 663 664 static inline bool mem_cgroup_swap_full(struct page *page) 665 { 666 return vm_swap_full(); 667 } 668 #endif 669 670 #endif /* __KERNEL__*/ 671 #endif /* _LINUX_SWAP_H */ 672