v4.19.13 snapshot.
diff --git a/include/linux/swap.h b/include/linux/swap.h
new file mode 100644
index 0000000..8e2c11e
--- /dev/null
+++ b/include/linux/swap.h
@@ -0,0 +1,683 @@
+/* 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/atomic.h>
+#include <linux/page-flags.h>
+#include <asm/page.h>
+
+struct notifier_block;
+
+struct bio;
+
+#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.
+ */
+
+/*
+ * Unaddressable device memory support. See include/linux/hmm.h and
+ * Documentation/vm/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_* entry.
+ */
+#ifdef CONFIG_DEVICE_PRIVATE
+#define SWP_DEVICE_NUM 2
+#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)
+#else
+#define SWP_DEVICE_NUM 0
+#endif
+
+/*
+ * NUMA node memory migration support
+ */
+#ifdef CONFIG_MIGRATION
+#define SWP_MIGRATION_NUM 2
+#define SWP_MIGRATION_READ (MAX_SWAPFILES + SWP_HWPOISON_NUM)
+#define SWP_MIGRATION_WRITE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1)
+#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)
+
+/*
+ * 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 list 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 list_head list;
+ pgoff_t start_page;
+ pgoff_t nr_pages;
+ sector_t start_block;
+};
+
+/*
+ * Max bad pages in the new format..
+ */
+#define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x)
+#define MAX_SWAP_BADPAGES \
+ ((__swapoffset(magic.magic) - __swapoffset(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_FILE = (1 << 7), /* set after swap_activate success */
+ SWP_AREA_DISCARD = (1 << 8), /* single-time swap area discards */
+ SWP_PAGE_DISCARD = (1 << 9), /* freed swap page-cluster discards */
+ SWP_STABLE_WRITES = (1 << 10), /* no overwrite PG_writeback pages */
+ SWP_SYNCHRONOUS_IO = (1 << 11), /* synchronous IO is efficient */
+ /* add others here before... */
+ SWP_SCANNING = (1 << 12), /* refcount in scan_swap_map */
+};
+
+#define SWAP_CLUSTER_MAX 32UL
+#define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX
+
+#define SWAP_MAP_MAX 0x3e /* Max duplication count, in first swap_map */
+#define SWAP_MAP_BAD 0x3f /* Note pageblock is bad, in first swap_map */
+#define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */
+#define SWAP_CONT_MAX 0x7f /* Max count, in each swap_map continuation */
+#define COUNT_CONTINUED 0x80 /* See swap_map continuation for full count */
+#define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs, in first swap_map */
+
+/*
+ * 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 {
+ 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 */
+ struct plist_node avail_lists[MAX_NUMNODES];/* entry in swap_avail_heads */
+ 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 */
+ struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */
+ struct swap_extent *curr_swap_extent;
+ struct swap_extent first_swap_extent;
+ struct block_device *bdev; /* swap device or bdev of swap file */
+ struct file *swap_file; /* seldom referenced */
+ unsigned int old_block_size; /* 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 */
+};
+
+#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
+};
+
+/* linux/mm/workingset.c */
+void *workingset_eviction(struct address_space *mapping, struct page *page);
+bool workingset_refault(void *shadow);
+void workingset_activation(struct page *page);
+
+/* Do not use directly, use workingset_lookup_update */
+void workingset_update_node(struct radix_tree_node *node);
+
+/* Returns workingset_update_node() if the mapping has shadow entries. */
+#define workingset_lookup_update(mapping) \
+({ \
+ radix_tree_update_node_t __helper = workingset_update_node; \
+ if (dax_mapping(mapping) || shmem_mapping(mapping)) \
+ __helper = NULL; \
+ __helper; \
+})
+
+/* linux/mm/page_alloc.c */
+extern unsigned long totalram_pages;
+extern unsigned long totalreserve_pages;
+extern unsigned long nr_free_buffer_pages(void);
+extern unsigned long nr_free_pagecache_pages(void);
+
+/* 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_cache_add(struct page *);
+extern void lru_cache_add_anon(struct page *page);
+extern void lru_cache_add_file(struct page *page);
+extern void lru_add_page_tail(struct page *page, struct page *page_tail,
+ struct lruvec *lruvec, struct list_head *head);
+extern void activate_page(struct page *);
+extern void mark_page_accessed(struct page *);
+extern void lru_add_drain(void);
+extern void lru_add_drain_cpu(int cpu);
+extern void lru_add_drain_all(void);
+extern void rotate_reclaimable_page(struct page *page);
+extern void deactivate_file_page(struct page *page);
+extern void mark_page_lazyfree(struct page *page);
+extern void swap_setup(void);
+
+extern void lru_cache_add_active_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);
+extern int __isolate_lru_page(struct page *page, isolate_mode_t mode);
+extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
+ unsigned long nr_pages,
+ gfp_t gfp_mask,
+ bool may_swap);
+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;
+extern int remove_mapping(struct address_space *mapping, struct page *page);
+extern unsigned long vm_total_pages;
+
+#ifdef CONFIG_NUMA
+extern int node_reclaim_mode;
+extern int sysctl_min_unmapped_ratio;
+extern int sysctl_min_slab_ratio;
+extern int node_reclaim(struct pglist_data *, gfp_t, unsigned int);
+#else
+#define node_reclaim_mode 0
+static inline int node_reclaim(struct pglist_data *pgdat, gfp_t mask,
+ unsigned int order)
+{
+ return 0;
+}
+#endif
+
+extern int page_evictable(struct page *page);
+extern void check_move_unevictable_pages(struct page **, int nr_pages);
+
+extern int kswapd_run(int nid);
+extern void kswapd_stop(int nid);
+
+#ifdef CONFIG_SWAP
+
+#include <linux/blk_types.h> /* for bio_end_io_t */
+
+/* linux/mm/page_io.c */
+extern int swap_readpage(struct page *page, bool do_poll);
+extern int swap_writepage(struct page *page, struct writeback_control *wbc);
+extern void end_swap_bio_write(struct bio *bio);
+extern int __swap_writepage(struct page *page, struct writeback_control *wbc,
+ bio_end_io_t end_write_func);
+extern int swap_set_page_dirty(struct page *page);
+
+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 *);
+
+/* linux/mm/swap_state.c */
+/* One swap address space for each 64M swap space */
+#define SWAP_ADDRESS_SPACE_SHIFT 14
+#define SWAP_ADDRESS_SPACE_PAGES (1 << SWAP_ADDRESS_SPACE_SHIFT)
+extern struct address_space *swapper_spaces[];
+#define swap_address_space(entry) \
+ (&swapper_spaces[swp_type(entry)][swp_offset(entry) \
+ >> SWAP_ADDRESS_SPACE_SHIFT])
+extern unsigned long total_swapcache_pages(void);
+extern void show_swap_cache_info(void);
+extern int add_to_swap(struct page *page);
+extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
+extern int __add_to_swap_cache(struct page *page, swp_entry_t entry);
+extern void __delete_from_swap_cache(struct page *);
+extern void delete_from_swap_cache(struct page *);
+extern void free_page_and_swap_cache(struct page *);
+extern void free_pages_and_swap_cache(struct page **, int);
+extern struct page *lookup_swap_cache(swp_entry_t entry,
+ struct vm_area_struct *vma,
+ unsigned long addr);
+extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
+ struct vm_area_struct *vma, unsigned long addr,
+ bool do_poll);
+extern struct page *__read_swap_cache_async(swp_entry_t, gfp_t,
+ struct vm_area_struct *vma, unsigned long addr,
+ bool *new_page_allocated);
+extern struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t flag,
+ struct vm_fault *vmf);
+extern struct page *swapin_readahead(swp_entry_t entry, gfp_t flag,
+ struct vm_fault *vmf);
+
+/* 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 *);
+extern swp_entry_t get_swap_page(struct page *page);
+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);
+extern int swap_type_of(dev_t, sector_t, struct block_device **);
+extern unsigned int count_swap_pages(int, int);
+extern sector_t map_swap_page(struct page *, struct block_device **);
+extern sector_t swapdev_block(int, pgoff_t);
+extern int page_swapcount(struct page *);
+extern int __swap_count(struct swap_info_struct *si, 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 bool reuse_swap_page(struct page *, int *);
+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);
+
+#else /* CONFIG_SWAP */
+
+static inline int swap_readpage(struct page *page, bool do_poll)
+{
+ return 0;
+}
+
+static inline struct swap_info_struct *swp_swap_info(swp_entry_t entry)
+{
+ return NULL;
+}
+
+#define swap_address_space(entry) (NULL)
+#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));
+
+static inline void show_swap_cache_info(void)
+{
+}
+
+#define free_swap_and_cache(e) ({(is_migration_entry(e) || is_device_private_entry(e));})
+#define swapcache_prepare(e) ({(is_migration_entry(e) || is_device_private_entry(e));})
+
+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 struct page *swap_cluster_readahead(swp_entry_t entry,
+ gfp_t gfp_mask, struct vm_fault *vmf)
+{
+ return NULL;
+}
+
+static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
+ struct vm_fault *vmf)
+{
+ return NULL;
+}
+
+static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
+{
+ return 0;
+}
+
+static inline struct page *lookup_swap_cache(swp_entry_t swp,
+ struct vm_area_struct *vma,
+ unsigned long addr)
+{
+ return NULL;
+}
+
+static inline int add_to_swap(struct page *page)
+{
+ return 0;
+}
+
+static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
+ gfp_t gfp_mask)
+{
+ return -1;
+}
+
+static inline void __delete_from_swap_cache(struct page *page)
+{
+}
+
+static inline void delete_from_swap_cache(struct page *page)
+{
+}
+
+static inline int page_swapcount(struct page *page)
+{
+ return 0;
+}
+
+static inline int __swap_count(struct swap_info_struct *si, 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;
+}
+
+#define reuse_swap_page(page, total_map_swapcount) \
+ (page_trans_huge_mapcount(page, total_map_swapcount) == 1)
+
+static inline int try_to_free_swap(struct page *page)
+{
+ return 0;
+}
+
+static inline swp_entry_t get_swap_page(struct page *page)
+{
+ swp_entry_t entry;
+ entry.val = 0;
+ return entry;
+}
+
+#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() || !memcg->css.parent)
+ return vm_swappiness;
+
+ return memcg->swappiness;
+}
+#else
+static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
+{
+ return vm_swappiness;
+}
+#endif
+
+#if defined(CONFIG_SWAP) && defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
+extern void mem_cgroup_throttle_swaprate(struct mem_cgroup *memcg, int node,
+ gfp_t gfp_mask);
+#else
+static inline void mem_cgroup_throttle_swaprate(struct mem_cgroup *memcg,
+ int node, gfp_t gfp_mask)
+{
+}
+#endif
+
+#ifdef CONFIG_MEMCG_SWAP
+extern void mem_cgroup_swapout(struct page *page, swp_entry_t entry);
+extern int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry);
+extern void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int 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 page *page, swp_entry_t entry)
+{
+}
+
+static inline int mem_cgroup_try_charge_swap(struct page *page,
+ 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 */