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 /* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _LINUX_SWAP_H
 #define _LINUX_SWAP_H
 
 #include <linux/spinlock.h>
 #include <linux/linkage.h>
 #include <linux/mmzone.h>
 #include <linux/list.h>
 #include <linux/memcontrol.h>
 #include <linux/sched.h>
 #include <linux/node.h>
 #include <linux/fs.h>
 #include <linux/pagemap.h>
 #include <linux/atomic.h>
 #include <linux/page-flags.h>
 #include <uapi/linux/mempolicy.h>
 #include <asm/page.h>
 
 struct notifier_block;
 
 struct bio;
 
 struct pagevec;
 
 #define SWAP_FLAG_PREFER    0x8000  /* set if swap priority specified */
 #define SWAP_FLAG_PRIO_MASK 0x7fff
 #define SWAP_FLAG_PRIO_SHIFT    0
 #define SWAP_FLAG_DISCARD   0x10000 /* enable discard for swap */
 #define SWAP_FLAG_DISCARD_ONCE  0x20000 /* discard swap area at swapon-time */
 #define SWAP_FLAG_DISCARD_PAGES 0x40000 /* discard page-clusters after use */
 
 #define SWAP_FLAGS_VALID    (SWAP_FLAG_PRIO_MASK | SWAP_FLAG_PREFER | \
                  SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE | \
                  SWAP_FLAG_DISCARD_PAGES)
 #define SWAP_BATCH 64
 
 static inline int current_is_kswapd(void)
 {
     return current->flags & PF_KSWAPD;
 }
 
 /*
  * MAX_SWAPFILES defines the maximum number of swaptypes: things which can
  * be swapped to.  The swap type and the offset into that swap type are
  * encoded into pte's and into pgoff_t's in the swapcache.  Using five bits
  * for the type means that the maximum number of swapcache pages is 27 bits
  * on 32-bit-pgoff_t architectures.  And that assumes that the architecture packs
  * the type/offset into the pte as 5/27 as well.
  */
 #define MAX_SWAPFILES_SHIFT 5
 
 /*
  * Use some of the swap files numbers for other purposes. This
  * is a convenient way to hook into the VM to trigger special
  * actions on faults.
  */
 
 #define SWP_SWAPIN_ERROR_NUM 1
 #define SWP_SWAPIN_ERROR     (MAX_SWAPFILES + SWP_HWPOISON_NUM + \
                  SWP_MIGRATION_NUM + SWP_DEVICE_NUM + \
                  SWP_PTE_MARKER_NUM)
 /*
  * PTE markers are used to persist information onto PTEs that are mapped with
  * file-backed memories.  As its name "PTE" hints, it should only be applied to
  * the leaves of pgtables.
  */
 #ifdef CONFIG_PTE_MARKER
 #define SWP_PTE_MARKER_NUM 1
 #define SWP_PTE_MARKER     (MAX_SWAPFILES + SWP_HWPOISON_NUM + \
                 SWP_MIGRATION_NUM + SWP_DEVICE_NUM)
 #else
 #define SWP_PTE_MARKER_NUM 0
 #endif
 
 /*
  * Unaddressable device memory support. See include/linux/hmm.h and
  * Documentation/mm/hmm.rst. Short description is we need struct pages for
  * device memory that is unaddressable (inaccessible) by CPU, so that we can
  * migrate part of a process memory to device memory.
  *
  * When a page is migrated from CPU to device, we set the CPU page table entry
  * to a special SWP_DEVICE_{READ|WRITE} entry.
  *
  * When a page is mapped by the device for exclusive access we set the CPU page
  * table entries to special SWP_DEVICE_EXCLUSIVE_* entries.
  */
 #ifdef CONFIG_DEVICE_PRIVATE
 #define SWP_DEVICE_NUM 4
 #define SWP_DEVICE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM)
 #define SWP_DEVICE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+1)
 #define SWP_DEVICE_EXCLUSIVE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+2)
 #define SWP_DEVICE_EXCLUSIVE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+3)
 #else
 #define SWP_DEVICE_NUM 0
 #endif
 
 /*
  * Page migration support.
  *
  * SWP_MIGRATION_READ_EXCLUSIVE is only applicable to anonymous pages and
  * indicates that the referenced (part of) an anonymous page is exclusive to
  * a single process. For SWP_MIGRATION_WRITE, that information is implicit:
  * (part of) an anonymous page that are mapped writable are exclusive to a
  * single process.
  */
 #ifdef CONFIG_MIGRATION
 #define SWP_MIGRATION_NUM 3
 #define SWP_MIGRATION_READ (MAX_SWAPFILES + SWP_HWPOISON_NUM)
 #define SWP_MIGRATION_READ_EXCLUSIVE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1)
 #define SWP_MIGRATION_WRITE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 2)
 #else
 #define SWP_MIGRATION_NUM 0
 #endif
 
 /*
  * Handling of hardware poisoned pages with memory corruption.
  */
 #ifdef CONFIG_MEMORY_FAILURE
 #define SWP_HWPOISON_NUM 1
 #define SWP_HWPOISON        MAX_SWAPFILES
 #else
 #define SWP_HWPOISON_NUM 0
 #endif
 
 #define MAX_SWAPFILES \
     ((1 << MAX_SWAPFILES_SHIFT) - SWP_DEVICE_NUM - \
     SWP_MIGRATION_NUM - SWP_HWPOISON_NUM - \
     SWP_PTE_MARKER_NUM - SWP_SWAPIN_ERROR_NUM)
 
 /*
  * Magic header for a swap area. The first part of the union is
  * what the swap magic looks like for the old (limited to 128MB)
  * swap area format, the second part of the union adds - in the
  * old reserved area - some extra information. Note that the first
  * kilobyte is reserved for boot loader or disk label stuff...
  *
  * Having the magic at the end of the PAGE_SIZE makes detecting swap
  * areas somewhat tricky on machines that support multiple page sizes.
  * For 2.5 we'll probably want to move the magic to just beyond the
  * bootbits...
  */
 union swap_header {
     struct {
         char reserved[PAGE_SIZE - 10];
         char magic[10];         /* SWAP-SPACE or SWAPSPACE2 */
     } magic;
     struct {
         char        bootbits[1024]; /* Space for disklabel etc. */
         __u32       version;
         __u32       last_page;
         __u32       nr_badpages;
         unsigned char   sws_uuid[16];
         unsigned char   sws_volume[16];
         __u32       padding[117];
         __u32       badpages[1];
     } info;
 };
 
 /*
  * current->reclaim_state points to one of these when a task is running
  * memory reclaim
  */
 struct reclaim_state {
     unsigned long reclaimed_slab;
 };
 
 #ifdef __KERNEL__
 
 struct address_space;
 struct sysinfo;
 struct writeback_control;
 struct zone;
 
 /*
  * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
  * disk blocks.  A rbtree of swap extents maps the entire swapfile (Where the
  * term `swapfile' refers to either a blockdevice or an IS_REG file). Apart
  * from setup, they're handled identically.
  *
  * We always assume that blocks are of size PAGE_SIZE.
  */
 struct swap_extent {
     struct rb_node rb_node;
     pgoff_t start_page;
     pgoff_t nr_pages;
     sector_t start_block;
 };
 
 /*
  * Max bad pages in the new format..
  */
 #define MAX_SWAP_BADPAGES \
     ((offsetof(union swap_header, magic.magic) - \
       offsetof(union swap_header, info.badpages)) / sizeof(int))
 
 enum {
     SWP_USED    = (1 << 0), /* is slot in swap_info[] used? */
     SWP_WRITEOK = (1 << 1), /* ok to write to this swap?    */
     SWP_DISCARDABLE = (1 << 2), /* blkdev support discard */
     SWP_DISCARDING  = (1 << 3), /* now discarding a free cluster */
     SWP_SOLIDSTATE  = (1 << 4), /* blkdev seeks are cheap */
     SWP_CONTINUED   = (1 << 5), /* swap_map has count continuation */
     SWP_BLKDEV  = (1 << 6), /* its a block device */
     SWP_ACTIVATED   = (1 << 7), /* set after swap_activate success */
     SWP_FS_OPS  = (1 << 8), /* swapfile operations go through fs */
     SWP_AREA_DISCARD = (1 << 9),    /* single-time swap area discards */
     SWP_PAGE_DISCARD = (1 << 10),   /* freed swap page-cluster discards */
     SWP_STABLE_WRITES = (1 << 11),  /* no overwrite PG_writeback pages */
     SWP_SYNCHRONOUS_IO = (1 << 12), /* synchronous IO is efficient */
                     /* add others here before... */
     SWP_SCANNING    = (1 << 14),    /* refcount in scan_swap_map */
 };
 
 #define SWAP_CLUSTER_MAX 32UL
 #define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX
 
 /* Bit flag in swap_map */
 #define SWAP_HAS_CACHE  0x40    /* Flag page is cached, in first swap_map */
 #define COUNT_CONTINUED 0x80    /* Flag swap_map continuation for full count */
 
 /* Special value in first swap_map */
 #define SWAP_MAP_MAX    0x3e    /* Max count */
 #define SWAP_MAP_BAD    0x3f    /* Note page is bad */
 #define SWAP_MAP_SHMEM  0xbf    /* Owned by shmem/tmpfs */
 
 /* Special value in each swap_map continuation */
 #define SWAP_CONT_MAX   0x7f    /* Max count */
 
 /*
  * We use this to track usage of a cluster. A cluster is a block of swap disk
  * space with SWAPFILE_CLUSTER pages long and naturally aligns in disk. All
  * free clusters are organized into a list. We fetch an entry from the list to
  * get a free cluster.
  *
  * The data field stores next cluster if the cluster is free or cluster usage
  * counter otherwise. The flags field determines if a cluster is free. This is
  * protected by swap_info_struct.lock.
  */
 struct swap_cluster_info {
     spinlock_t lock;    /*
                  * Protect swap_cluster_info fields
                  * and swap_info_struct->swap_map
                  * elements correspond to the swap
                  * cluster
                  */
     unsigned int data:24;
     unsigned int flags:8;
 };
 #define CLUSTER_FLAG_FREE 1 /* This cluster is free */
 #define CLUSTER_FLAG_NEXT_NULL 2 /* This cluster has no next cluster */
 #define CLUSTER_FLAG_HUGE 4 /* This cluster is backing a transparent huge page */
 
 /*
  * We assign a cluster to each CPU, so each CPU can allocate swap entry from
  * its own cluster and swapout sequentially. The purpose is to optimize swapout
  * throughput.
  */
 struct percpu_cluster {
     struct swap_cluster_info index; /* Current cluster index */
     unsigned int next; /* Likely next allocation offset */
 };
 
 struct swap_cluster_list {
     struct swap_cluster_info head;
     struct swap_cluster_info tail;
 };
 
 /*
  * The in-memory structure used to track swap areas.
  */
 struct swap_info_struct {
     struct percpu_ref users;    /* indicate and keep swap device valid. */
     unsigned long   flags;      /* SWP_USED etc: see above */
     signed short    prio;       /* swap priority of this type */
     struct plist_node list;     /* entry in swap_active_head */
     signed char type;       /* strange name for an index */
     unsigned int    max;        /* extent of the swap_map */
     unsigned char *swap_map;    /* vmalloc'ed array of usage counts */
     struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */
     struct swap_cluster_list free_clusters; /* free clusters list */
     unsigned int lowest_bit;    /* index of first free in swap_map */
     unsigned int highest_bit;   /* index of last free in swap_map */
     unsigned int pages;     /* total of usable pages of swap */
     unsigned int inuse_pages;   /* number of those currently in use */
     unsigned int cluster_next;  /* likely index for next allocation */
     unsigned int cluster_nr;    /* countdown to next cluster search */
     unsigned int __percpu *cluster_next_cpu; /*percpu index for next allocation */
     struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */
     struct rb_root swap_extent_root;/* root of the swap extent rbtree */
     struct block_device *bdev;  /* swap device or bdev of swap file */
     struct file *swap_file;     /* seldom referenced */
     unsigned int old_block_size;    /* seldom referenced */
     struct completion comp;     /* seldom referenced */
 #ifdef CONFIG_FRONTSWAP
     unsigned long *frontswap_map;   /* frontswap in-use, one bit per page */
     atomic_t frontswap_pages;   /* frontswap pages in-use counter */
 #endif
     spinlock_t lock;        /*
                      * protect map scan related fields like
                      * swap_map, lowest_bit, highest_bit,
                      * inuse_pages, cluster_next,
                      * cluster_nr, lowest_alloc,
                      * highest_alloc, free/discard cluster
                      * list. other fields are only changed
                      * at swapon/swapoff, so are protected
                      * by swap_lock. changing flags need
                      * hold this lock and swap_lock. If
                      * both locks need hold, hold swap_lock
                      * first.
                      */
     spinlock_t cont_lock;       /*
                      * protect swap count continuation page
                      * list.
                      */
     struct work_struct discard_work; /* discard worker */
     struct swap_cluster_list discard_clusters; /* discard clusters list */
     struct plist_node avail_lists[]; /*
                        * entries in swap_avail_heads, one
                        * entry per node.
                        * Must be last as the number of the
                        * array is nr_node_ids, which is not
                        * a fixed value so have to allocate
                        * dynamically.
                        * And it has to be an array so that
                        * plist_for_each_* can work.
                        */
 };
 
 #ifdef CONFIG_64BIT
 #define SWAP_RA_ORDER_CEILING   5
 #else
 /* Avoid stack overflow, because we need to save part of page table */
 #define SWAP_RA_ORDER_CEILING   3
 #define SWAP_RA_PTE_CACHE_SIZE  (1 << SWAP_RA_ORDER_CEILING)
 #endif
 
 struct vma_swap_readahead {
     unsigned short win;
     unsigned short offset;
     unsigned short nr_pte;
 #ifdef CONFIG_64BIT
     pte_t *ptes;
 #else
     pte_t ptes[SWAP_RA_PTE_CACHE_SIZE];
 #endif
 };
 
 static inline swp_entry_t folio_swap_entry(struct folio *folio)
 {
     swp_entry_t entry = { .val = page_private(&folio->page) };
     return entry;
 }
 
 /* linux/mm/workingset.c */
 void workingset_age_nonresident(struct lruvec *lruvec, unsigned long nr_pages);
 void *workingset_eviction(struct folio *folio, struct mem_cgroup *target_memcg);
 void workingset_refault(struct folio *folio, void *shadow);
 void workingset_activation(struct folio *folio);
 
 /* Only track the nodes of mappings with shadow entries */
 void workingset_update_node(struct xa_node *node);
 extern struct list_lru shadow_nodes;
 #define mapping_set_update(xas, mapping) do {               \
     if (!dax_mapping(mapping) && !shmem_mapping(mapping)) {     \
         xas_set_update(xas, workingset_update_node);        \
         xas_set_lru(xas, &shadow_nodes);            \
     }                               \
 } while (0)
 
 /* linux/mm/page_alloc.c */
 extern unsigned long totalreserve_pages;
 
 /* Definition of global_zone_page_state not available yet */
 #define nr_free_pages() global_zone_page_state(NR_FREE_PAGES)
 
 
 /* linux/mm/swap.c */
 extern void lru_note_cost(struct lruvec *lruvec, bool file,
               unsigned int nr_pages);
 extern void lru_note_cost_folio(struct folio *);
 extern void folio_add_lru(struct folio *);
 extern void lru_cache_add(struct page *);
 void mark_page_accessed(struct page *);
 void folio_mark_accessed(struct folio *);
 
 extern atomic_t lru_disable_count;
 
 static inline bool lru_cache_disabled(void)
 {
     return atomic_read(&lru_disable_count);
 }
 
 static inline void lru_cache_enable(void)
 {
     atomic_dec(&lru_disable_count);
 }
 
 extern void lru_cache_disable(void);
 extern void lru_add_drain(void);
 extern void lru_add_drain_cpu(int cpu);
 extern void lru_add_drain_cpu_zone(struct zone *zone);
 extern void lru_add_drain_all(void);
 extern void deactivate_page(struct page *page);
 extern void mark_page_lazyfree(struct page *page);
 extern void swap_setup(void);
 
 extern void lru_cache_add_inactive_or_unevictable(struct page *page,
                         struct vm_area_struct *vma);
 
 /* linux/mm/vmscan.c */
 extern unsigned long zone_reclaimable_pages(struct zone *zone);
 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
                     gfp_t gfp_mask, nodemask_t *mask);
 
 #define MEMCG_RECLAIM_MAY_SWAP (1 << 1)
 #define MEMCG_RECLAIM_PROACTIVE (1 << 2)
 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
                           unsigned long nr_pages,
                           gfp_t gfp_mask,
                           unsigned int reclaim_options);
 extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem,
                         gfp_t gfp_mask, bool noswap,
                         pg_data_t *pgdat,
                         unsigned long *nr_scanned);
 extern unsigned long shrink_all_memory(unsigned long nr_pages);
 extern int vm_swappiness;
 long remove_mapping(struct address_space *mapping, struct folio *folio);
 
 extern unsigned long reclaim_pages(struct list_head *page_list);
 #ifdef CONFIG_NUMA
 extern int node_reclaim_mode;
 extern int sysctl_min_unmapped_ratio;
 extern int sysctl_min_slab_ratio;
 #else
 #define node_reclaim_mode 0
 #endif
 
 static inline bool node_reclaim_enabled(void)
 {
     /* Is any node_reclaim_mode bit set? */
     return node_reclaim_mode & (RECLAIM_ZONE|RECLAIM_WRITE|RECLAIM_UNMAP);
 }
 
 void check_move_unevictable_folios(struct folio_batch *fbatch);
 void check_move_unevictable_pages(struct pagevec *pvec);
 
 extern void kswapd_run(int nid);
 extern void kswapd_stop(int nid);
 
 #ifdef CONFIG_SWAP
 
 int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
         unsigned long nr_pages, sector_t start_block);
 int generic_swapfile_activate(struct swap_info_struct *, struct file *,
         sector_t *);
 
 static inline unsigned long total_swapcache_pages(void)
 {
     return global_node_page_state(NR_SWAPCACHE);
 }
 
 extern void free_swap_cache(struct page *page);
 extern void free_page_and_swap_cache(struct page *);
 extern void free_pages_and_swap_cache(struct page **, int);
 /* linux/mm/swapfile.c */
 extern atomic_long_t nr_swap_pages;
 extern long total_swap_pages;
 extern atomic_t nr_rotate_swap;
 extern bool has_usable_swap(void);
 
 /* Swap 50% full? Release swapcache more aggressively.. */
 static inline bool vm_swap_full(void)
 {
     return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages;
 }
 
 static inline long get_nr_swap_pages(void)
 {
     return atomic_long_read(&nr_swap_pages);
 }
 
 extern void si_swapinfo(struct sysinfo *);
 swp_entry_t folio_alloc_swap(struct folio *folio);
 extern void put_swap_page(struct page *page, swp_entry_t entry);
 extern swp_entry_t get_swap_page_of_type(int);
 extern int get_swap_pages(int n, swp_entry_t swp_entries[], int entry_size);
 extern int add_swap_count_continuation(swp_entry_t, gfp_t);
 extern void swap_shmem_alloc(swp_entry_t);
 extern int swap_duplicate(swp_entry_t);
 extern int swapcache_prepare(swp_entry_t);
 extern void swap_free(swp_entry_t);
 extern void swapcache_free_entries(swp_entry_t *entries, int n);
 extern int free_swap_and_cache(swp_entry_t);
 int swap_type_of(dev_t device, sector_t offset);
 int find_first_swap(dev_t *device);
 extern unsigned int count_swap_pages(int, int);
 extern sector_t swapdev_block(int, pgoff_t);
 extern int __swap_count(swp_entry_t entry);
 extern int __swp_swapcount(swp_entry_t entry);
 extern int swp_swapcount(swp_entry_t entry);
 extern struct swap_info_struct *page_swap_info(struct page *);
 extern struct swap_info_struct *swp_swap_info(swp_entry_t entry);
 extern int try_to_free_swap(struct page *);
 struct backing_dev_info;
 extern int init_swap_address_space(unsigned int type, unsigned long nr_pages);
 extern void exit_swap_address_space(unsigned int type);
 extern struct swap_info_struct *get_swap_device(swp_entry_t entry);
 sector_t swap_page_sector(struct page *page);
 
 static inline void put_swap_device(struct swap_info_struct *si)
 {
     percpu_ref_put(&si->users);
 }
 
 #else /* CONFIG_SWAP */
 static inline struct swap_info_struct *swp_swap_info(swp_entry_t entry)
 {
     return NULL;
 }
 
 static inline struct swap_info_struct *get_swap_device(swp_entry_t entry)
 {
     return NULL;
 }
 
 static inline void put_swap_device(struct swap_info_struct *si)
 {
 }
 
 #define get_nr_swap_pages()         0L
 #define total_swap_pages            0L
 #define total_swapcache_pages()         0UL
 #define vm_swap_full()              0
 
 #define si_swapinfo(val) \
     do { (val)->freeswap = (val)->totalswap = 0; } while (0)
 /* only sparc can not include linux/pagemap.h in this file
  * so leave put_page and release_pages undeclared... */
 #define free_page_and_swap_cache(page) \
     put_page(page)
 #define free_pages_and_swap_cache(pages, nr) \
     release_pages((pages), (nr));
 
 /* used to sanity check ptes in zap_pte_range when CONFIG_SWAP=0 */
 #define free_swap_and_cache(e) is_pfn_swap_entry(e)
 
 static inline void free_swap_cache(struct page *page)
 {
 }
 
 static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask)
 {
     return 0;
 }
 
 static inline void swap_shmem_alloc(swp_entry_t swp)
 {
 }
 
 static inline int swap_duplicate(swp_entry_t swp)
 {
     return 0;
 }
 
 static inline void swap_free(swp_entry_t swp)
 {
 }
 
 static inline void put_swap_page(struct page *page, swp_entry_t swp)
 {
 }
 
 static inline int __swap_count(swp_entry_t entry)
 {
     return 0;
 }
 
 static inline int __swp_swapcount(swp_entry_t entry)
 {
     return 0;
 }
 
 static inline int swp_swapcount(swp_entry_t entry)
 {
     return 0;
 }
 
 static inline int try_to_free_swap(struct page *page)
 {
     return 0;
 }
 
 static inline swp_entry_t folio_alloc_swap(struct folio *folio)
 {
     swp_entry_t entry;
     entry.val = 0;
     return entry;
 }
 
 static inline int add_swap_extent(struct swap_info_struct *sis,
                   unsigned long start_page,
                   unsigned long nr_pages, sector_t start_block)
 {
     return -EINVAL;
 }
 #endif /* CONFIG_SWAP */
 
 #ifdef CONFIG_THP_SWAP
 extern int split_swap_cluster(swp_entry_t entry);
 #else
 static inline int split_swap_cluster(swp_entry_t entry)
 {
     return 0;
 }
 #endif
 
 #ifdef CONFIG_MEMCG
 static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg)
 {
     /* Cgroup2 doesn't have per-cgroup swappiness */
     if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
         return vm_swappiness;
 
     /* root ? */
     if (mem_cgroup_disabled() || mem_cgroup_is_root(memcg))
         return vm_swappiness;
 
     return memcg->swappiness;
 }
 #else
 static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
 {
     return vm_swappiness;
 }
 #endif
 
 #ifdef CONFIG_ZSWAP
 extern u64 zswap_pool_total_size;
 extern atomic_t zswap_stored_pages;
 #endif
 
 #if defined(CONFIG_SWAP) && defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
 extern void __cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask);
 static inline  void cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask)
 {
     if (mem_cgroup_disabled())
         return;
     __cgroup_throttle_swaprate(page, gfp_mask);
 }
 #else
 static inline void cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask)
 {
 }
 #endif
 static inline void folio_throttle_swaprate(struct folio *folio, gfp_t gfp)
 {
     cgroup_throttle_swaprate(&folio->page, gfp);
 }
 
 #ifdef CONFIG_MEMCG_SWAP
 void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry);
 int __mem_cgroup_try_charge_swap(struct folio *folio, swp_entry_t entry);
 static inline int mem_cgroup_try_charge_swap(struct folio *folio,
         swp_entry_t entry)
 {
     if (mem_cgroup_disabled())
         return 0;
     return __mem_cgroup_try_charge_swap(folio, entry);
 }
 
 extern void __mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages);
 static inline void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages)
 {
     if (mem_cgroup_disabled())
         return;
     __mem_cgroup_uncharge_swap(entry, nr_pages);
 }
 
 extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg);
 extern bool mem_cgroup_swap_full(struct page *page);
 #else
 static inline void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry)
 {
 }
 
 static inline int mem_cgroup_try_charge_swap(struct folio *folio,
                          swp_entry_t entry)
 {
     return 0;
 }
 
 static inline void mem_cgroup_uncharge_swap(swp_entry_t entry,
                         unsigned int nr_pages)
 {
 }
 
 static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)
 {
     return get_nr_swap_pages();
 }
 
 static inline bool mem_cgroup_swap_full(struct page *page)
 {
     return vm_swap_full();
 }
 #endif
 
 #endif /* __KERNEL__*/
 #endif /* _LINUX_SWAP_H */

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