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 struct pagevec; 22 23 #define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */ 24 #define SWAP_FLAG_PRIO_MASK 0x7fff 25 #define SWAP_FLAG_PRIO_SHIFT 0 26 #define SWAP_FLAG_DISCARD 0x10000 /* enable discard for swap */ 27 #define SWAP_FLAG_DISCARD_ONCE 0x20000 /* discard swap area at swapon-time */ 28 #define SWAP_FLAG_DISCARD_PAGES 0x40000 /* discard page-clusters after use */ 29 30 #define SWAP_FLAGS_VALID (SWAP_FLAG_PRIO_MASK | SWAP_FLAG_PREFER | \ 31 SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE | \ 32 SWAP_FLAG_DISCARD_PAGES) 33 #define SWAP_BATCH 64 34 35 static inline int current_is_kswapd(void) 36 { 37 return current->flags & PF_KSWAPD; 38 } 39 40 /* 41 * MAX_SWAPFILES defines the maximum number of swaptypes: things which can 42 * be swapped to. The swap type and the offset into that swap type are 43 * encoded into pte's and into pgoff_t's in the swapcache. Using five bits 44 * for the type means that the maximum number of swapcache pages is 27 bits 45 * on 32-bit-pgoff_t architectures. And that assumes that the architecture packs 46 * the type/offset into the pte as 5/27 as well. 47 */ 48 #define MAX_SWAPFILES_SHIFT 5 49 50 /* 51 * Use some of the swap files numbers for other purposes. This 52 * is a convenient way to hook into the VM to trigger special 53 * actions on faults. 54 */ 55 56 /* 57 * Unaddressable device memory support. See include/linux/hmm.h and 58 * Documentation/vm/hmm.rst. Short description is we need struct pages for 59 * device memory that is unaddressable (inaccessible) by CPU, so that we can 60 * migrate part of a process memory to device memory. 61 * 62 * When a page is migrated from CPU to device, we set the CPU page table entry 63 * to a special SWP_DEVICE_* entry. 64 */ 65 #ifdef CONFIG_DEVICE_PRIVATE 66 #define SWP_DEVICE_NUM 2 67 #define SWP_DEVICE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM) 68 #define SWP_DEVICE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+1) 69 #else 70 #define SWP_DEVICE_NUM 0 71 #endif 72 73 /* 74 * NUMA node memory migration support 75 */ 76 #ifdef CONFIG_MIGRATION 77 #define SWP_MIGRATION_NUM 2 78 #define SWP_MIGRATION_READ (MAX_SWAPFILES + SWP_HWPOISON_NUM) 79 #define SWP_MIGRATION_WRITE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1) 80 #else 81 #define SWP_MIGRATION_NUM 0 82 #endif 83 84 /* 85 * Handling of hardware poisoned pages with memory corruption. 86 */ 87 #ifdef CONFIG_MEMORY_FAILURE 88 #define SWP_HWPOISON_NUM 1 89 #define SWP_HWPOISON MAX_SWAPFILES 90 #else 91 #define SWP_HWPOISON_NUM 0 92 #endif 93 94 #define MAX_SWAPFILES \ 95 ((1 << MAX_SWAPFILES_SHIFT) - SWP_DEVICE_NUM - \ 96 SWP_MIGRATION_NUM - SWP_HWPOISON_NUM) 97 98 /* 99 * Magic header for a swap area. The first part of the union is 100 * what the swap magic looks like for the old (limited to 128MB) 101 * swap area format, the second part of the union adds - in the 102 * old reserved area - some extra information. Note that the first 103 * kilobyte is reserved for boot loader or disk label stuff... 104 * 105 * Having the magic at the end of the PAGE_SIZE makes detecting swap 106 * areas somewhat tricky on machines that support multiple page sizes. 107 * For 2.5 we'll probably want to move the magic to just beyond the 108 * bootbits... 109 */ 110 union swap_header { 111 struct { 112 char reserved[PAGE_SIZE - 10]; 113 char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */ 114 } magic; 115 struct { 116 char bootbits[1024]; /* Space for disklabel etc. */ 117 __u32 version; 118 __u32 last_page; 119 __u32 nr_badpages; 120 unsigned char sws_uuid[16]; 121 unsigned char sws_volume[16]; 122 __u32 padding[117]; 123 __u32 badpages[1]; 124 } info; 125 }; 126 127 /* 128 * current->reclaim_state points to one of these when a task is running 129 * memory reclaim 130 */ 131 struct reclaim_state { 132 unsigned long reclaimed_slab; 133 }; 134 135 #ifdef __KERNEL__ 136 137 struct address_space; 138 struct sysinfo; 139 struct writeback_control; 140 struct zone; 141 142 /* 143 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of 144 * disk blocks. A list of swap extents maps the entire swapfile. (Where the 145 * term `swapfile' refers to either a blockdevice or an IS_REG file. Apart 146 * from setup, they're handled identically. 147 * 148 * We always assume that blocks are of size PAGE_SIZE. 149 */ 150 struct swap_extent { 151 struct list_head list; 152 pgoff_t start_page; 153 pgoff_t nr_pages; 154 sector_t start_block; 155 }; 156 157 /* 158 * Max bad pages in the new format.. 159 */ 160 #define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x) 161 #define MAX_SWAP_BADPAGES \ 162 ((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int)) 163 164 enum { 165 SWP_USED = (1 << 0), /* is slot in swap_info[] used? */ 166 SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */ 167 SWP_DISCARDABLE = (1 << 2), /* blkdev support discard */ 168 SWP_DISCARDING = (1 << 3), /* now discarding a free cluster */ 169 SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */ 170 SWP_CONTINUED = (1 << 5), /* swap_map has count continuation */ 171 SWP_BLKDEV = (1 << 6), /* its a block device */ 172 SWP_ACTIVATED = (1 << 7), /* set after swap_activate success */ 173 SWP_FS = (1 << 8), /* swap file goes through fs */ 174 SWP_AREA_DISCARD = (1 << 9), /* single-time swap area discards */ 175 SWP_PAGE_DISCARD = (1 << 10), /* freed swap page-cluster discards */ 176 SWP_STABLE_WRITES = (1 << 11), /* no overwrite PG_writeback pages */ 177 SWP_SYNCHRONOUS_IO = (1 << 12), /* synchronous IO is efficient */ 178 /* add others here before... */ 179 SWP_SCANNING = (1 << 13), /* refcount in scan_swap_map */ 180 }; 181 182 #define SWAP_CLUSTER_MAX 32UL 183 #define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX 184 185 #define SWAP_MAP_MAX 0x3e /* Max duplication count, in first swap_map */ 186 #define SWAP_MAP_BAD 0x3f /* Note pageblock is bad, in first swap_map */ 187 #define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */ 188 #define SWAP_CONT_MAX 0x7f /* Max count, in each swap_map continuation */ 189 #define COUNT_CONTINUED 0x80 /* See swap_map continuation for full count */ 190 #define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs, in first swap_map */ 191 192 /* 193 * We use this to track usage of a cluster. A cluster is a block of swap disk 194 * space with SWAPFILE_CLUSTER pages long and naturally aligns in disk. All 195 * free clusters are organized into a list. We fetch an entry from the list to 196 * get a free cluster. 197 * 198 * The data field stores next cluster if the cluster is free or cluster usage 199 * counter otherwise. The flags field determines if a cluster is free. This is 200 * protected by swap_info_struct.lock. 201 */ 202 struct swap_cluster_info { 203 spinlock_t lock; /* 204 * Protect swap_cluster_info fields 205 * and swap_info_struct->swap_map 206 * elements correspond to the swap 207 * cluster 208 */ 209 unsigned int data:24; 210 unsigned int flags:8; 211 }; 212 #define CLUSTER_FLAG_FREE 1 /* This cluster is free */ 213 #define CLUSTER_FLAG_NEXT_NULL 2 /* This cluster has no next cluster */ 214 #define CLUSTER_FLAG_HUGE 4 /* This cluster is backing a transparent huge page */ 215 216 /* 217 * We assign a cluster to each CPU, so each CPU can allocate swap entry from 218 * its own cluster and swapout sequentially. The purpose is to optimize swapout 219 * throughput. 220 */ 221 struct percpu_cluster { 222 struct swap_cluster_info index; /* Current cluster index */ 223 unsigned int next; /* Likely next allocation offset */ 224 }; 225 226 struct swap_cluster_list { 227 struct swap_cluster_info head; 228 struct swap_cluster_info tail; 229 }; 230 231 /* 232 * The in-memory structure used to track swap areas. 233 */ 234 struct swap_info_struct { 235 unsigned long flags; /* SWP_USED etc: see above */ 236 signed short prio; /* swap priority of this type */ 237 struct plist_node list; /* entry in swap_active_head */ 238 struct plist_node avail_lists[MAX_NUMNODES];/* entry in swap_avail_heads */ 239 signed char type; /* strange name for an index */ 240 unsigned int max; /* extent of the swap_map */ 241 unsigned char *swap_map; /* vmalloc'ed array of usage counts */ 242 struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */ 243 struct swap_cluster_list free_clusters; /* free clusters list */ 244 unsigned int lowest_bit; /* index of first free in swap_map */ 245 unsigned int highest_bit; /* index of last free in swap_map */ 246 unsigned int pages; /* total of usable pages of swap */ 247 unsigned int inuse_pages; /* number of those currently in use */ 248 unsigned int cluster_next; /* likely index for next allocation */ 249 unsigned int cluster_nr; /* countdown to next cluster search */ 250 struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */ 251 struct swap_extent *curr_swap_extent; 252 struct swap_extent first_swap_extent; 253 struct block_device *bdev; /* swap device or bdev of swap file */ 254 struct file *swap_file; /* seldom referenced */ 255 unsigned int old_block_size; /* seldom referenced */ 256 #ifdef CONFIG_FRONTSWAP 257 unsigned long *frontswap_map; /* frontswap in-use, one bit per page */ 258 atomic_t frontswap_pages; /* frontswap pages in-use counter */ 259 #endif 260 spinlock_t lock; /* 261 * protect map scan related fields like 262 * swap_map, lowest_bit, highest_bit, 263 * inuse_pages, cluster_next, 264 * cluster_nr, lowest_alloc, 265 * highest_alloc, free/discard cluster 266 * list. other fields are only changed 267 * at swapon/swapoff, so are protected 268 * by swap_lock. changing flags need 269 * hold this lock and swap_lock. If 270 * both locks need hold, hold swap_lock 271 * first. 272 */ 273 spinlock_t cont_lock; /* 274 * protect swap count continuation page 275 * list. 276 */ 277 struct work_struct discard_work; /* discard worker */ 278 struct swap_cluster_list discard_clusters; /* discard clusters list */ 279 }; 280 281 #ifdef CONFIG_64BIT 282 #define SWAP_RA_ORDER_CEILING 5 283 #else 284 /* Avoid stack overflow, because we need to save part of page table */ 285 #define SWAP_RA_ORDER_CEILING 3 286 #define SWAP_RA_PTE_CACHE_SIZE (1 << SWAP_RA_ORDER_CEILING) 287 #endif 288 289 struct vma_swap_readahead { 290 unsigned short win; 291 unsigned short offset; 292 unsigned short nr_pte; 293 #ifdef CONFIG_64BIT 294 pte_t *ptes; 295 #else 296 pte_t ptes[SWAP_RA_PTE_CACHE_SIZE]; 297 #endif 298 }; 299 300 /* linux/mm/workingset.c */ 301 void *workingset_eviction(struct address_space *mapping, struct page *page); 302 void workingset_refault(struct page *page, void *shadow); 303 void workingset_activation(struct page *page); 304 305 /* Only track the nodes of mappings with shadow entries */ 306 void workingset_update_node(struct xa_node *node); 307 #define mapping_set_update(xas, mapping) do { \ 308 if (!dax_mapping(mapping) && !shmem_mapping(mapping)) \ 309 xas_set_update(xas, workingset_update_node); \ 310 } while (0) 311 312 /* linux/mm/page_alloc.c */ 313 extern unsigned long totalram_pages; 314 extern unsigned long totalreserve_pages; 315 extern unsigned long nr_free_buffer_pages(void); 316 extern unsigned long nr_free_pagecache_pages(void); 317 318 /* Definition of global_zone_page_state not available yet */ 319 #define nr_free_pages() global_zone_page_state(NR_FREE_PAGES) 320 321 322 /* linux/mm/swap.c */ 323 extern void lru_cache_add(struct page *); 324 extern void lru_cache_add_anon(struct page *page); 325 extern void lru_cache_add_file(struct page *page); 326 extern void lru_add_page_tail(struct page *page, struct page *page_tail, 327 struct lruvec *lruvec, struct list_head *head); 328 extern void activate_page(struct page *); 329 extern void mark_page_accessed(struct page *); 330 extern void lru_add_drain(void); 331 extern void lru_add_drain_cpu(int cpu); 332 extern void lru_add_drain_all(void); 333 extern void rotate_reclaimable_page(struct page *page); 334 extern void deactivate_file_page(struct page *page); 335 extern void mark_page_lazyfree(struct page *page); 336 extern void swap_setup(void); 337 338 extern void lru_cache_add_active_or_unevictable(struct page *page, 339 struct vm_area_struct *vma); 340 341 /* linux/mm/vmscan.c */ 342 extern unsigned long zone_reclaimable_pages(struct zone *zone); 343 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order, 344 gfp_t gfp_mask, nodemask_t *mask); 345 extern int __isolate_lru_page(struct page *page, isolate_mode_t mode); 346 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg, 347 unsigned long nr_pages, 348 gfp_t gfp_mask, 349 bool may_swap); 350 extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem, 351 gfp_t gfp_mask, bool noswap, 352 pg_data_t *pgdat, 353 unsigned long *nr_scanned); 354 extern unsigned long shrink_all_memory(unsigned long nr_pages); 355 extern int vm_swappiness; 356 extern int remove_mapping(struct address_space *mapping, struct page *page); 357 extern unsigned long vm_total_pages; 358 359 #ifdef CONFIG_NUMA 360 extern int node_reclaim_mode; 361 extern int sysctl_min_unmapped_ratio; 362 extern int sysctl_min_slab_ratio; 363 extern int node_reclaim(struct pglist_data *, gfp_t, unsigned int); 364 #else 365 #define node_reclaim_mode 0 366 static inline int node_reclaim(struct pglist_data *pgdat, gfp_t mask, 367 unsigned int order) 368 { 369 return 0; 370 } 371 #endif 372 373 extern int page_evictable(struct page *page); 374 extern void check_move_unevictable_pages(struct pagevec *pvec); 375 376 extern int kswapd_run(int nid); 377 extern void kswapd_stop(int nid); 378 379 #ifdef CONFIG_SWAP 380 381 #include <linux/blk_types.h> /* for bio_end_io_t */ 382 383 /* linux/mm/page_io.c */ 384 extern int swap_readpage(struct page *page, bool do_poll); 385 extern int swap_writepage(struct page *page, struct writeback_control *wbc); 386 extern void end_swap_bio_write(struct bio *bio); 387 extern int __swap_writepage(struct page *page, struct writeback_control *wbc, 388 bio_end_io_t end_write_func); 389 extern int swap_set_page_dirty(struct page *page); 390 391 int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, 392 unsigned long nr_pages, sector_t start_block); 393 int generic_swapfile_activate(struct swap_info_struct *, struct file *, 394 sector_t *); 395 396 /* linux/mm/swap_state.c */ 397 /* One swap address space for each 64M swap space */ 398 #define SWAP_ADDRESS_SPACE_SHIFT 14 399 #define SWAP_ADDRESS_SPACE_PAGES (1 << SWAP_ADDRESS_SPACE_SHIFT) 400 extern struct address_space *swapper_spaces[]; 401 #define swap_address_space(entry) \ 402 (&swapper_spaces[swp_type(entry)][swp_offset(entry) \ 403 >> SWAP_ADDRESS_SPACE_SHIFT]) 404 extern unsigned long total_swapcache_pages(void); 405 extern void show_swap_cache_info(void); 406 extern int add_to_swap(struct page *page); 407 extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t); 408 extern int __add_to_swap_cache(struct page *page, swp_entry_t entry); 409 extern void __delete_from_swap_cache(struct page *, swp_entry_t entry); 410 extern void delete_from_swap_cache(struct page *); 411 extern void free_page_and_swap_cache(struct page *); 412 extern void free_pages_and_swap_cache(struct page **, int); 413 extern struct page *lookup_swap_cache(swp_entry_t entry, 414 struct vm_area_struct *vma, 415 unsigned long addr); 416 extern struct page *read_swap_cache_async(swp_entry_t, gfp_t, 417 struct vm_area_struct *vma, unsigned long addr, 418 bool do_poll); 419 extern struct page *__read_swap_cache_async(swp_entry_t, gfp_t, 420 struct vm_area_struct *vma, unsigned long addr, 421 bool *new_page_allocated); 422 extern struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t flag, 423 struct vm_fault *vmf); 424 extern struct page *swapin_readahead(swp_entry_t entry, gfp_t flag, 425 struct vm_fault *vmf); 426 427 /* linux/mm/swapfile.c */ 428 extern atomic_long_t nr_swap_pages; 429 extern long total_swap_pages; 430 extern atomic_t nr_rotate_swap; 431 extern bool has_usable_swap(void); 432 433 /* Swap 50% full? Release swapcache more aggressively.. */ 434 static inline bool vm_swap_full(void) 435 { 436 return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages; 437 } 438 439 static inline long get_nr_swap_pages(void) 440 { 441 return atomic_long_read(&nr_swap_pages); 442 } 443 444 extern void si_swapinfo(struct sysinfo *); 445 extern swp_entry_t get_swap_page(struct page *page); 446 extern void put_swap_page(struct page *page, swp_entry_t entry); 447 extern swp_entry_t get_swap_page_of_type(int); 448 extern int get_swap_pages(int n, swp_entry_t swp_entries[], int entry_size); 449 extern int add_swap_count_continuation(swp_entry_t, gfp_t); 450 extern void swap_shmem_alloc(swp_entry_t); 451 extern int swap_duplicate(swp_entry_t); 452 extern int swapcache_prepare(swp_entry_t); 453 extern void swap_free(swp_entry_t); 454 extern void swapcache_free_entries(swp_entry_t *entries, int n); 455 extern int free_swap_and_cache(swp_entry_t); 456 extern int swap_type_of(dev_t, sector_t, struct block_device **); 457 extern unsigned int count_swap_pages(int, int); 458 extern sector_t map_swap_page(struct page *, struct block_device **); 459 extern sector_t swapdev_block(int, pgoff_t); 460 extern int page_swapcount(struct page *); 461 extern int __swap_count(struct swap_info_struct *si, swp_entry_t entry); 462 extern int __swp_swapcount(swp_entry_t entry); 463 extern int swp_swapcount(swp_entry_t entry); 464 extern struct swap_info_struct *page_swap_info(struct page *); 465 extern struct swap_info_struct *swp_swap_info(swp_entry_t entry); 466 extern bool reuse_swap_page(struct page *, int *); 467 extern int try_to_free_swap(struct page *); 468 struct backing_dev_info; 469 extern int init_swap_address_space(unsigned int type, unsigned long nr_pages); 470 extern void exit_swap_address_space(unsigned int type); 471 472 #else /* CONFIG_SWAP */ 473 474 static inline int swap_readpage(struct page *page, bool do_poll) 475 { 476 return 0; 477 } 478 479 static inline struct swap_info_struct *swp_swap_info(swp_entry_t entry) 480 { 481 return NULL; 482 } 483 484 #define swap_address_space(entry) (NULL) 485 #define get_nr_swap_pages() 0L 486 #define total_swap_pages 0L 487 #define total_swapcache_pages() 0UL 488 #define vm_swap_full() 0 489 490 #define si_swapinfo(val) \ 491 do { (val)->freeswap = (val)->totalswap = 0; } while (0) 492 /* only sparc can not include linux/pagemap.h in this file 493 * so leave put_page and release_pages undeclared... */ 494 #define free_page_and_swap_cache(page) \ 495 put_page(page) 496 #define free_pages_and_swap_cache(pages, nr) \ 497 release_pages((pages), (nr)); 498 499 static inline void show_swap_cache_info(void) 500 { 501 } 502 503 #define free_swap_and_cache(e) ({(is_migration_entry(e) || is_device_private_entry(e));}) 504 #define swapcache_prepare(e) ({(is_migration_entry(e) || is_device_private_entry(e));}) 505 506 static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask) 507 { 508 return 0; 509 } 510 511 static inline void swap_shmem_alloc(swp_entry_t swp) 512 { 513 } 514 515 static inline int swap_duplicate(swp_entry_t swp) 516 { 517 return 0; 518 } 519 520 static inline void swap_free(swp_entry_t swp) 521 { 522 } 523 524 static inline void put_swap_page(struct page *page, swp_entry_t swp) 525 { 526 } 527 528 static inline struct page *swap_cluster_readahead(swp_entry_t entry, 529 gfp_t gfp_mask, struct vm_fault *vmf) 530 { 531 return NULL; 532 } 533 534 static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask, 535 struct vm_fault *vmf) 536 { 537 return NULL; 538 } 539 540 static inline int swap_writepage(struct page *p, struct writeback_control *wbc) 541 { 542 return 0; 543 } 544 545 static inline struct page *lookup_swap_cache(swp_entry_t swp, 546 struct vm_area_struct *vma, 547 unsigned long addr) 548 { 549 return NULL; 550 } 551 552 static inline int add_to_swap(struct page *page) 553 { 554 return 0; 555 } 556 557 static inline int add_to_swap_cache(struct page *page, swp_entry_t entry, 558 gfp_t gfp_mask) 559 { 560 return -1; 561 } 562 563 static inline void __delete_from_swap_cache(struct page *page, 564 swp_entry_t entry) 565 { 566 } 567 568 static inline void delete_from_swap_cache(struct page *page) 569 { 570 } 571 572 static inline int page_swapcount(struct page *page) 573 { 574 return 0; 575 } 576 577 static inline int __swap_count(struct swap_info_struct *si, swp_entry_t entry) 578 { 579 return 0; 580 } 581 582 static inline int __swp_swapcount(swp_entry_t entry) 583 { 584 return 0; 585 } 586 587 static inline int swp_swapcount(swp_entry_t entry) 588 { 589 return 0; 590 } 591 592 #define reuse_swap_page(page, total_map_swapcount) \ 593 (page_trans_huge_mapcount(page, total_map_swapcount) == 1) 594 595 static inline int try_to_free_swap(struct page *page) 596 { 597 return 0; 598 } 599 600 static inline swp_entry_t get_swap_page(struct page *page) 601 { 602 swp_entry_t entry; 603 entry.val = 0; 604 return entry; 605 } 606 607 #endif /* CONFIG_SWAP */ 608 609 #ifdef CONFIG_THP_SWAP 610 extern int split_swap_cluster(swp_entry_t entry); 611 #else 612 static inline int split_swap_cluster(swp_entry_t entry) 613 { 614 return 0; 615 } 616 #endif 617 618 #ifdef CONFIG_MEMCG 619 static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg) 620 { 621 /* Cgroup2 doesn't have per-cgroup swappiness */ 622 if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) 623 return vm_swappiness; 624 625 /* root ? */ 626 if (mem_cgroup_disabled() || !memcg->css.parent) 627 return vm_swappiness; 628 629 return memcg->swappiness; 630 } 631 #else 632 static inline int mem_cgroup_swappiness(struct mem_cgroup *mem) 633 { 634 return vm_swappiness; 635 } 636 #endif 637 638 #if defined(CONFIG_SWAP) && defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP) 639 extern void mem_cgroup_throttle_swaprate(struct mem_cgroup *memcg, int node, 640 gfp_t gfp_mask); 641 #else 642 static inline void mem_cgroup_throttle_swaprate(struct mem_cgroup *memcg, 643 int node, gfp_t gfp_mask) 644 { 645 } 646 #endif 647 648 #ifdef CONFIG_MEMCG_SWAP 649 extern void mem_cgroup_swapout(struct page *page, swp_entry_t entry); 650 extern int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry); 651 extern void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages); 652 extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg); 653 extern bool mem_cgroup_swap_full(struct page *page); 654 #else 655 static inline void mem_cgroup_swapout(struct page *page, swp_entry_t entry) 656 { 657 } 658 659 static inline int mem_cgroup_try_charge_swap(struct page *page, 660 swp_entry_t entry) 661 { 662 return 0; 663 } 664 665 static inline void mem_cgroup_uncharge_swap(swp_entry_t entry, 666 unsigned int nr_pages) 667 { 668 } 669 670 static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg) 671 { 672 return get_nr_swap_pages(); 673 } 674 675 static inline bool mem_cgroup_swap_full(struct page *page) 676 { 677 return vm_swap_full(); 678 } 679 #endif 680 681 #endif /* __KERNEL__*/ 682 #endif /* _LINUX_SWAP_H */ 683