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.rst. 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_ACTIVATED = (1 << 7), /* set after swap_activate success */ 171 SWP_FS = (1 << 8), /* swap file goes through fs */ 172 SWP_AREA_DISCARD = (1 << 9), /* single-time swap area discards */ 173 SWP_PAGE_DISCARD = (1 << 10), /* freed swap page-cluster discards */ 174 SWP_STABLE_WRITES = (1 << 11), /* no overwrite PG_writeback pages */ 175 SWP_SYNCHRONOUS_IO = (1 << 12), /* synchronous IO is efficient */ 176 /* add others here before... */ 177 SWP_SCANNING = (1 << 13), /* refcount in scan_swap_map */ 178 }; 179 180 #define SWAP_CLUSTER_MAX 32UL 181 #define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX 182 183 #define SWAP_MAP_MAX 0x3e /* Max duplication count, in first swap_map */ 184 #define SWAP_MAP_BAD 0x3f /* Note pageblock is bad, in first swap_map */ 185 #define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */ 186 #define SWAP_CONT_MAX 0x7f /* Max count, in each swap_map continuation */ 187 #define COUNT_CONTINUED 0x80 /* See swap_map continuation for full count */ 188 #define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs, in first swap_map */ 189 190 /* 191 * We use this to track usage of a cluster. A cluster is a block of swap disk 192 * space with SWAPFILE_CLUSTER pages long and naturally aligns in disk. All 193 * free clusters are organized into a list. We fetch an entry from the list to 194 * get a free cluster. 195 * 196 * The data field stores next cluster if the cluster is free or cluster usage 197 * counter otherwise. The flags field determines if a cluster is free. This is 198 * protected by swap_info_struct.lock. 199 */ 200 struct swap_cluster_info { 201 spinlock_t lock; /* 202 * Protect swap_cluster_info fields 203 * and swap_info_struct->swap_map 204 * elements correspond to the swap 205 * cluster 206 */ 207 unsigned int data:24; 208 unsigned int flags:8; 209 }; 210 #define CLUSTER_FLAG_FREE 1 /* This cluster is free */ 211 #define CLUSTER_FLAG_NEXT_NULL 2 /* This cluster has no next cluster */ 212 #define CLUSTER_FLAG_HUGE 4 /* This cluster is backing a transparent huge page */ 213 214 /* 215 * We assign a cluster to each CPU, so each CPU can allocate swap entry from 216 * its own cluster and swapout sequentially. The purpose is to optimize swapout 217 * throughput. 218 */ 219 struct percpu_cluster { 220 struct swap_cluster_info index; /* Current cluster index */ 221 unsigned int next; /* Likely next allocation offset */ 222 }; 223 224 struct swap_cluster_list { 225 struct swap_cluster_info head; 226 struct swap_cluster_info tail; 227 }; 228 229 /* 230 * The in-memory structure used to track swap areas. 231 */ 232 struct swap_info_struct { 233 unsigned long flags; /* SWP_USED etc: see above */ 234 signed short prio; /* swap priority of this type */ 235 struct plist_node list; /* entry in swap_active_head */ 236 struct plist_node avail_lists[MAX_NUMNODES];/* entry in swap_avail_heads */ 237 signed char type; /* strange name for an index */ 238 unsigned int max; /* extent of the swap_map */ 239 unsigned char *swap_map; /* vmalloc'ed array of usage counts */ 240 struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */ 241 struct swap_cluster_list free_clusters; /* free clusters list */ 242 unsigned int lowest_bit; /* index of first free in swap_map */ 243 unsigned int highest_bit; /* index of last free in swap_map */ 244 unsigned int pages; /* total of usable pages of swap */ 245 unsigned int inuse_pages; /* number of those currently in use */ 246 unsigned int cluster_next; /* likely index for next allocation */ 247 unsigned int cluster_nr; /* countdown to next cluster search */ 248 struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */ 249 struct swap_extent *curr_swap_extent; 250 struct swap_extent first_swap_extent; 251 struct block_device *bdev; /* swap device or bdev of swap file */ 252 struct file *swap_file; /* seldom referenced */ 253 unsigned int old_block_size; /* seldom referenced */ 254 #ifdef CONFIG_FRONTSWAP 255 unsigned long *frontswap_map; /* frontswap in-use, one bit per page */ 256 atomic_t frontswap_pages; /* frontswap pages in-use counter */ 257 #endif 258 spinlock_t lock; /* 259 * protect map scan related fields like 260 * swap_map, lowest_bit, highest_bit, 261 * inuse_pages, cluster_next, 262 * cluster_nr, lowest_alloc, 263 * highest_alloc, free/discard cluster 264 * list. other fields are only changed 265 * at swapon/swapoff, so are protected 266 * by swap_lock. changing flags need 267 * hold this lock and swap_lock. If 268 * both locks need hold, hold swap_lock 269 * first. 270 */ 271 spinlock_t cont_lock; /* 272 * protect swap count continuation page 273 * list. 274 */ 275 struct work_struct discard_work; /* discard worker */ 276 struct swap_cluster_list discard_clusters; /* discard clusters list */ 277 }; 278 279 #ifdef CONFIG_64BIT 280 #define SWAP_RA_ORDER_CEILING 5 281 #else 282 /* Avoid stack overflow, because we need to save part of page table */ 283 #define SWAP_RA_ORDER_CEILING 3 284 #define SWAP_RA_PTE_CACHE_SIZE (1 << SWAP_RA_ORDER_CEILING) 285 #endif 286 287 struct vma_swap_readahead { 288 unsigned short win; 289 unsigned short offset; 290 unsigned short nr_pte; 291 #ifdef CONFIG_64BIT 292 pte_t *ptes; 293 #else 294 pte_t ptes[SWAP_RA_PTE_CACHE_SIZE]; 295 #endif 296 }; 297 298 /* linux/mm/workingset.c */ 299 void *workingset_eviction(struct address_space *mapping, struct page *page); 300 void workingset_refault(struct page *page, void *shadow); 301 void workingset_activation(struct page *page); 302 303 /* Only track the nodes of mappings with shadow entries */ 304 void workingset_update_node(struct xa_node *node); 305 #define mapping_set_update(xas, mapping) do { \ 306 if (!dax_mapping(mapping) && !shmem_mapping(mapping)) \ 307 xas_set_update(xas, workingset_update_node); \ 308 } while (0) 309 310 /* linux/mm/page_alloc.c */ 311 extern unsigned long totalram_pages; 312 extern unsigned long totalreserve_pages; 313 extern unsigned long nr_free_buffer_pages(void); 314 extern unsigned long nr_free_pagecache_pages(void); 315 316 /* Definition of global_zone_page_state not available yet */ 317 #define nr_free_pages() global_zone_page_state(NR_FREE_PAGES) 318 319 320 /* linux/mm/swap.c */ 321 extern void lru_cache_add(struct page *); 322 extern void lru_cache_add_anon(struct page *page); 323 extern void lru_cache_add_file(struct page *page); 324 extern void lru_add_page_tail(struct page *page, struct page *page_tail, 325 struct lruvec *lruvec, struct list_head *head); 326 extern void activate_page(struct page *); 327 extern void mark_page_accessed(struct page *); 328 extern void lru_add_drain(void); 329 extern void lru_add_drain_cpu(int cpu); 330 extern void lru_add_drain_all(void); 331 extern void rotate_reclaimable_page(struct page *page); 332 extern void deactivate_file_page(struct page *page); 333 extern void mark_page_lazyfree(struct page *page); 334 extern void swap_setup(void); 335 336 extern void lru_cache_add_active_or_unevictable(struct page *page, 337 struct vm_area_struct *vma); 338 339 /* linux/mm/vmscan.c */ 340 extern unsigned long zone_reclaimable_pages(struct zone *zone); 341 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order, 342 gfp_t gfp_mask, nodemask_t *mask); 343 extern int __isolate_lru_page(struct page *page, isolate_mode_t mode); 344 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg, 345 unsigned long nr_pages, 346 gfp_t gfp_mask, 347 bool may_swap); 348 extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem, 349 gfp_t gfp_mask, bool noswap, 350 pg_data_t *pgdat, 351 unsigned long *nr_scanned); 352 extern unsigned long shrink_all_memory(unsigned long nr_pages); 353 extern int vm_swappiness; 354 extern int remove_mapping(struct address_space *mapping, struct page *page); 355 extern unsigned long vm_total_pages; 356 357 #ifdef CONFIG_NUMA 358 extern int node_reclaim_mode; 359 extern int sysctl_min_unmapped_ratio; 360 extern int sysctl_min_slab_ratio; 361 extern int node_reclaim(struct pglist_data *, gfp_t, unsigned int); 362 #else 363 #define node_reclaim_mode 0 364 static inline int node_reclaim(struct pglist_data *pgdat, gfp_t mask, 365 unsigned int order) 366 { 367 return 0; 368 } 369 #endif 370 371 extern int page_evictable(struct page *page); 372 extern void check_move_unevictable_pages(struct page **, int nr_pages); 373 374 extern int kswapd_run(int nid); 375 extern void kswapd_stop(int nid); 376 377 #ifdef CONFIG_SWAP 378 379 #include <linux/blk_types.h> /* for bio_end_io_t */ 380 381 /* linux/mm/page_io.c */ 382 extern int swap_readpage(struct page *page, bool do_poll); 383 extern int swap_writepage(struct page *page, struct writeback_control *wbc); 384 extern void end_swap_bio_write(struct bio *bio); 385 extern int __swap_writepage(struct page *page, struct writeback_control *wbc, 386 bio_end_io_t end_write_func); 387 extern int swap_set_page_dirty(struct page *page); 388 389 int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, 390 unsigned long nr_pages, sector_t start_block); 391 int generic_swapfile_activate(struct swap_info_struct *, struct file *, 392 sector_t *); 393 394 /* linux/mm/swap_state.c */ 395 /* One swap address space for each 64M swap space */ 396 #define SWAP_ADDRESS_SPACE_SHIFT 14 397 #define SWAP_ADDRESS_SPACE_PAGES (1 << SWAP_ADDRESS_SPACE_SHIFT) 398 extern struct address_space *swapper_spaces[]; 399 #define swap_address_space(entry) \ 400 (&swapper_spaces[swp_type(entry)][swp_offset(entry) \ 401 >> SWAP_ADDRESS_SPACE_SHIFT]) 402 extern unsigned long total_swapcache_pages(void); 403 extern void show_swap_cache_info(void); 404 extern int add_to_swap(struct page *page); 405 extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t); 406 extern int __add_to_swap_cache(struct page *page, swp_entry_t entry); 407 extern void __delete_from_swap_cache(struct page *, swp_entry_t entry); 408 extern void delete_from_swap_cache(struct page *); 409 extern void free_page_and_swap_cache(struct page *); 410 extern void free_pages_and_swap_cache(struct page **, int); 411 extern struct page *lookup_swap_cache(swp_entry_t entry, 412 struct vm_area_struct *vma, 413 unsigned long addr); 414 extern struct page *read_swap_cache_async(swp_entry_t, gfp_t, 415 struct vm_area_struct *vma, unsigned long addr, 416 bool do_poll); 417 extern struct page *__read_swap_cache_async(swp_entry_t, gfp_t, 418 struct vm_area_struct *vma, unsigned long addr, 419 bool *new_page_allocated); 420 extern struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t flag, 421 struct vm_fault *vmf); 422 extern struct page *swapin_readahead(swp_entry_t entry, gfp_t flag, 423 struct vm_fault *vmf); 424 425 /* linux/mm/swapfile.c */ 426 extern atomic_long_t nr_swap_pages; 427 extern long total_swap_pages; 428 extern atomic_t nr_rotate_swap; 429 extern bool has_usable_swap(void); 430 431 /* Swap 50% full? Release swapcache more aggressively.. */ 432 static inline bool vm_swap_full(void) 433 { 434 return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages; 435 } 436 437 static inline long get_nr_swap_pages(void) 438 { 439 return atomic_long_read(&nr_swap_pages); 440 } 441 442 extern void si_swapinfo(struct sysinfo *); 443 extern swp_entry_t get_swap_page(struct page *page); 444 extern void put_swap_page(struct page *page, swp_entry_t entry); 445 extern swp_entry_t get_swap_page_of_type(int); 446 extern int get_swap_pages(int n, swp_entry_t swp_entries[], int entry_size); 447 extern int add_swap_count_continuation(swp_entry_t, gfp_t); 448 extern void swap_shmem_alloc(swp_entry_t); 449 extern int swap_duplicate(swp_entry_t); 450 extern int swapcache_prepare(swp_entry_t); 451 extern void swap_free(swp_entry_t); 452 extern void swapcache_free_entries(swp_entry_t *entries, int n); 453 extern int free_swap_and_cache(swp_entry_t); 454 extern int swap_type_of(dev_t, sector_t, struct block_device **); 455 extern unsigned int count_swap_pages(int, int); 456 extern sector_t map_swap_page(struct page *, struct block_device **); 457 extern sector_t swapdev_block(int, pgoff_t); 458 extern int page_swapcount(struct page *); 459 extern int __swap_count(struct swap_info_struct *si, swp_entry_t entry); 460 extern int __swp_swapcount(swp_entry_t entry); 461 extern int swp_swapcount(swp_entry_t entry); 462 extern struct swap_info_struct *page_swap_info(struct page *); 463 extern struct swap_info_struct *swp_swap_info(swp_entry_t entry); 464 extern bool reuse_swap_page(struct page *, int *); 465 extern int try_to_free_swap(struct page *); 466 struct backing_dev_info; 467 extern int init_swap_address_space(unsigned int type, unsigned long nr_pages); 468 extern void exit_swap_address_space(unsigned int type); 469 470 #else /* CONFIG_SWAP */ 471 472 static inline int swap_readpage(struct page *page, bool do_poll) 473 { 474 return 0; 475 } 476 477 static inline struct swap_info_struct *swp_swap_info(swp_entry_t entry) 478 { 479 return NULL; 480 } 481 482 #define swap_address_space(entry) (NULL) 483 #define get_nr_swap_pages() 0L 484 #define total_swap_pages 0L 485 #define total_swapcache_pages() 0UL 486 #define vm_swap_full() 0 487 488 #define si_swapinfo(val) \ 489 do { (val)->freeswap = (val)->totalswap = 0; } while (0) 490 /* only sparc can not include linux/pagemap.h in this file 491 * so leave put_page and release_pages undeclared... */ 492 #define free_page_and_swap_cache(page) \ 493 put_page(page) 494 #define free_pages_and_swap_cache(pages, nr) \ 495 release_pages((pages), (nr)); 496 497 static inline void show_swap_cache_info(void) 498 { 499 } 500 501 #define free_swap_and_cache(e) ({(is_migration_entry(e) || is_device_private_entry(e));}) 502 #define swapcache_prepare(e) ({(is_migration_entry(e) || is_device_private_entry(e));}) 503 504 static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask) 505 { 506 return 0; 507 } 508 509 static inline void swap_shmem_alloc(swp_entry_t swp) 510 { 511 } 512 513 static inline int swap_duplicate(swp_entry_t swp) 514 { 515 return 0; 516 } 517 518 static inline void swap_free(swp_entry_t swp) 519 { 520 } 521 522 static inline void put_swap_page(struct page *page, swp_entry_t swp) 523 { 524 } 525 526 static inline struct page *swap_cluster_readahead(swp_entry_t entry, 527 gfp_t gfp_mask, struct vm_fault *vmf) 528 { 529 return NULL; 530 } 531 532 static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask, 533 struct vm_fault *vmf) 534 { 535 return NULL; 536 } 537 538 static inline int swap_writepage(struct page *p, struct writeback_control *wbc) 539 { 540 return 0; 541 } 542 543 static inline struct page *lookup_swap_cache(swp_entry_t swp, 544 struct vm_area_struct *vma, 545 unsigned long addr) 546 { 547 return NULL; 548 } 549 550 static inline int add_to_swap(struct page *page) 551 { 552 return 0; 553 } 554 555 static inline int add_to_swap_cache(struct page *page, swp_entry_t entry, 556 gfp_t gfp_mask) 557 { 558 return -1; 559 } 560 561 static inline void __delete_from_swap_cache(struct page *page, 562 swp_entry_t entry) 563 { 564 } 565 566 static inline void delete_from_swap_cache(struct page *page) 567 { 568 } 569 570 static inline int page_swapcount(struct page *page) 571 { 572 return 0; 573 } 574 575 static inline int __swap_count(struct swap_info_struct *si, swp_entry_t entry) 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 #else 630 static inline int mem_cgroup_swappiness(struct mem_cgroup *mem) 631 { 632 return vm_swappiness; 633 } 634 #endif 635 636 #if defined(CONFIG_SWAP) && defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP) 637 extern void mem_cgroup_throttle_swaprate(struct mem_cgroup *memcg, int node, 638 gfp_t gfp_mask); 639 #else 640 static inline void mem_cgroup_throttle_swaprate(struct mem_cgroup *memcg, 641 int node, gfp_t gfp_mask) 642 { 643 } 644 #endif 645 646 #ifdef CONFIG_MEMCG_SWAP 647 extern void mem_cgroup_swapout(struct page *page, swp_entry_t entry); 648 extern int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry); 649 extern void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages); 650 extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg); 651 extern bool mem_cgroup_swap_full(struct page *page); 652 #else 653 static inline void mem_cgroup_swapout(struct page *page, swp_entry_t entry) 654 { 655 } 656 657 static inline int mem_cgroup_try_charge_swap(struct page *page, 658 swp_entry_t entry) 659 { 660 return 0; 661 } 662 663 static inline void mem_cgroup_uncharge_swap(swp_entry_t entry, 664 unsigned int nr_pages) 665 { 666 } 667 668 static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg) 669 { 670 return get_nr_swap_pages(); 671 } 672 673 static inline bool mem_cgroup_swap_full(struct page *page) 674 { 675 return vm_swap_full(); 676 } 677 #endif 678 679 #endif /* __KERNEL__*/ 680 #endif /* _LINUX_SWAP_H */ 681