Quelle mmzone.h Sprache: C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_MMZONE_H
#define _LINUX_MMZONE_H

#ifndef __ASSEMBLY__
#ifndef __GENERATING_BOUNDS_H

#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/list_nulls.h>
#include <linux/wait.h>
#include <linux/bitops.h>
#include <linux/cache.h>
#include <linux/threads.h>
#include <linux/numa.h>
#include <linux/init.h>
#include <linux/seqlock.h>
#include <linux/nodemask.h>
#include <linux/pageblock-flags.h>
#include <linux/page-flags-layout.h>
#include <linux/atomic.h>
#include <linux/mm_types.h>
#include <linux/page-flags.h>
#include <linux/local_lock.h>
#include <linux/zswap.h>
#include <asm/page.h>

/* Free memory management - zoned buddy allocator.  */
#ifndef CONFIG_ARCH_FORCE_MAX_ORDER
#define MAX_PAGE_ORDER 10
#else
#define MAX_PAGE_ORDER CONFIG_ARCH_FORCE_MAX_ORDER
#endif
#define MAX_ORDER_NR_PAGES (1 << MAX_PAGE_ORDER)

#define IS_MAX_ORDER_ALIGNED(pfn) IS_ALIGNED(pfn, MAX_ORDER_NR_PAGES)

#define NR_PAGE_ORDERS (MAX_PAGE_ORDER + 1)

/* Defines the order for the number of pages that have a migrate type. */
#ifndef CONFIG_PAGE_BLOCK_MAX_ORDER
#define PAGE_BLOCK_MAX_ORDER MAX_PAGE_ORDER
#else
#define PAGE_BLOCK_MAX_ORDER CONFIG_PAGE_BLOCK_MAX_ORDER
#endif /* CONFIG_PAGE_BLOCK_MAX_ORDER */

/*
* The MAX_PAGE_ORDER, which defines the max order of pages to be allocated
* by the buddy allocator, has to be larger or equal to the PAGE_BLOCK_MAX_ORDER,
* which defines the order for the number of pages that can have a migrate type
*/
#if (PAGE_BLOCK_MAX_ORDER > MAX_PAGE_ORDER)
#error MAX_PAGE_ORDER must be >= PAGE_BLOCK_MAX_ORDER
#endif

/*
* PAGE_ALLOC_COSTLY_ORDER is the order at which allocations are deemed
* costly to service.  That is between allocation orders which should
* coalesce naturally under reasonable reclaim pressure and those which
* will not.
*/
#define PAGE_ALLOC_COSTLY_ORDER 3

enum migratetype {
MIGRATE_UNMOVABLE,
MIGRATE_MOVABLE,
MIGRATE_RECLAIMABLE,
MIGRATE_PCPTYPES, /* the number of types on the pcp lists */
MIGRATE_HIGHATOMIC = MIGRATE_PCPTYPES,
#ifdef CONFIG_CMA
/*
* MIGRATE_CMA migration type is designed to mimic the way
* ZONE_MOVABLE works.  Only movable pages can be allocated
* from MIGRATE_CMA pageblocks and page allocator never
* implicitly change migration type of MIGRATE_CMA pageblock.
*
* The way to use it is to change migratetype of a range of
* pageblocks to MIGRATE_CMA which can be done by
* __free_pageblock_cma() function.
*/
MIGRATE_CMA,
__MIGRATE_TYPE_END = MIGRATE_CMA,
#else
__MIGRATE_TYPE_END = MIGRATE_HIGHATOMIC,
#endif
#ifdef CONFIG_MEMORY_ISOLATION
MIGRATE_ISOLATE, /* can't allocate from here */
#endif
MIGRATE_TYPES
};

/* In mm/page_alloc.c; keep in sync also with show_migration_types() there */
extern const char * const migratetype_names[MIGRATE_TYPES];

#ifdef CONFIG_CMA
#  define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA)
#  define is_migrate_cma_page(_page) (get_pageblock_migratetype(_page) == MIGRATE_CMA)
/*
* __dump_folio() in mm/debug.c passes a folio pointer to on-stack struct folio,
* so folio_pfn() cannot be used and pfn is needed.
*/
#  define is_migrate_cma_folio(folio, pfn) \
(get_pfnblock_migratetype(&folio->page, pfn) == MIGRATE_CMA)
#else
#  define is_migrate_cma(migratetype) false
#  define is_migrate_cma_page(_page) false
#  define is_migrate_cma_folio(folio, pfn) false
#endif

static inline bool is_migrate_movable(int mt)
{
return is_migrate_cma(mt) || mt == MIGRATE_MOVABLE;
}

/*
* Check whether a migratetype can be merged with another migratetype.
*
* It is only mergeable when it can fall back to other migratetypes for
* allocation. See fallbacks[MIGRATE_TYPES][3] in page_alloc.c.
*/
static inline bool migratetype_is_mergeable(int mt)
{
return mt < MIGRATE_PCPTYPES;
}

#define for_each_migratetype_order(order, type) \
for (order = 0; order < NR_PAGE_ORDERS; order++) \
  for (type = 0; type < MIGRATE_TYPES; type++)

extern int page_group_by_mobility_disabled;

#define get_pageblock_migratetype(page) \
get_pfnblock_migratetype(page, page_to_pfn(page))

#define folio_migratetype(folio) \
get_pageblock_migratetype(&folio->page)

struct free_area {
struct list_head free_list[MIGRATE_TYPES];
unsigned long  nr_free;
};

struct pglist_data;

#ifdef CONFIG_NUMA
enum numa_stat_item {
NUMA_HIT,  /* allocated in intended node */
NUMA_MISS,  /* allocated in non intended node */
NUMA_FOREIGN,  /* was intended here, hit elsewhere */
NUMA_INTERLEAVE_HIT, /* interleaver preferred this zone */
NUMA_LOCAL,  /* allocation from local node */
NUMA_OTHER,  /* allocation from other node */
NR_VM_NUMA_EVENT_ITEMS
};
#else
#define NR_VM_NUMA_EVENT_ITEMS 0
#endif

enum zone_stat_item {
/* First 128 byte cacheline (assuming 64 bit words) */
NR_FREE_PAGES,
NR_FREE_PAGES_BLOCKS,
NR_ZONE_LRU_BASE, /* Used only for compaction and reclaim retry */
NR_ZONE_INACTIVE_ANON = NR_ZONE_LRU_BASE,
NR_ZONE_ACTIVE_ANON,
NR_ZONE_INACTIVE_FILE,
NR_ZONE_ACTIVE_FILE,
NR_ZONE_UNEVICTABLE,
NR_ZONE_WRITE_PENDING, /* Count of dirty, writeback and unstable pages */
NR_MLOCK,  /* mlock()ed pages found and moved off LRU */
/* Second 128 byte cacheline */
#if IS_ENABLED(CONFIG_ZSMALLOC)
NR_ZSPAGES,  /* allocated in zsmalloc */
#endif
NR_FREE_CMA_PAGES,
#ifdef CONFIG_UNACCEPTED_MEMORY
NR_UNACCEPTED,
#endif
NR_VM_ZONE_STAT_ITEMS };

enum node_stat_item {
NR_LRU_BASE,
NR_INACTIVE_ANON = NR_LRU_BASE, /* must match order of LRU_[IN]ACTIVE */
NR_ACTIVE_ANON,  /*  "     "     "   "       "         */
NR_INACTIVE_FILE, /*  "     "     "   "       "         */
NR_ACTIVE_FILE,  /*  "     "     "   "       "         */
NR_UNEVICTABLE,  /*  "     "     "   "       "         */
NR_SLAB_RECLAIMABLE_B,
NR_SLAB_UNRECLAIMABLE_B,
NR_ISOLATED_ANON, /* Temporary isolated pages from anon lru */
NR_ISOLATED_FILE, /* Temporary isolated pages from file lru */
WORKINGSET_NODES,
WORKINGSET_REFAULT_BASE,
WORKINGSET_REFAULT_ANON = WORKINGSET_REFAULT_BASE,
WORKINGSET_REFAULT_FILE,
WORKINGSET_ACTIVATE_BASE,
WORKINGSET_ACTIVATE_ANON = WORKINGSET_ACTIVATE_BASE,
WORKINGSET_ACTIVATE_FILE,
WORKINGSET_RESTORE_BASE,
WORKINGSET_RESTORE_ANON = WORKINGSET_RESTORE_BASE,
WORKINGSET_RESTORE_FILE,
WORKINGSET_NODERECLAIM,
NR_ANON_MAPPED, /* Mapped anonymous pages */
NR_FILE_MAPPED, /* pagecache pages mapped into pagetables.
   only modified from process context */
NR_FILE_PAGES,
NR_FILE_DIRTY,
NR_WRITEBACK,
NR_SHMEM,  /* shmem pages (included tmpfs/GEM pages) */
NR_SHMEM_THPS,
NR_SHMEM_PMDMAPPED,
NR_FILE_THPS,
NR_FILE_PMDMAPPED,
NR_ANON_THPS,
NR_VMSCAN_WRITE,
NR_VMSCAN_IMMEDIATE, /* Prioritise for reclaim when writeback ends */
NR_DIRTIED,  /* page dirtyings since bootup */
NR_WRITTEN,  /* page writings since bootup */
NR_THROTTLED_WRITTEN, /* NR_WRITTEN while reclaim throttled */
NR_KERNEL_MISC_RECLAIMABLE, /* reclaimable non-slab kernel pages */
NR_FOLL_PIN_ACQUIRED, /* via: pin_user_page(), gup flag: FOLL_PIN */
NR_FOLL_PIN_RELEASED, /* pages returned via unpin_user_page() */
NR_KERNEL_STACK_KB, /* measured in KiB */
#if IS_ENABLED(CONFIG_SHADOW_CALL_STACK)
NR_KERNEL_SCS_KB, /* measured in KiB */
#endif
NR_PAGETABLE,  /* used for pagetables */
NR_SECONDARY_PAGETABLE, /* secondary pagetables, KVM & IOMMU */
#ifdef CONFIG_IOMMU_SUPPORT
NR_IOMMU_PAGES,  /* # of pages allocated by IOMMU */
#endif
#ifdef CONFIG_SWAP
NR_SWAPCACHE,
#endif
#ifdef CONFIG_NUMA_BALANCING
PGPROMOTE_SUCCESS, /* promote successfully */
PGPROMOTE_CANDIDATE, /* candidate pages to promote */
#endif
/* PGDEMOTE_*: pages demoted */
PGDEMOTE_KSWAPD,
PGDEMOTE_DIRECT,
PGDEMOTE_KHUGEPAGED,
PGDEMOTE_PROACTIVE,
#ifdef CONFIG_HUGETLB_PAGE
NR_HUGETLB,
#endif
NR_BALLOON_PAGES,
NR_VM_NODE_STAT_ITEMS
};

/*
* Returns true if the item should be printed in THPs (/proc/vmstat
* currently prints number of anon, file and shmem THPs. But the item
* is charged in pages).
*/
static __always_inline bool vmstat_item_print_in_thp(enum node_stat_item item)
{
if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
  return false;

return item == NR_ANON_THPS ||
        item == NR_FILE_THPS ||
        item == NR_SHMEM_THPS ||
        item == NR_SHMEM_PMDMAPPED ||
        item == NR_FILE_PMDMAPPED;
}

/*
* Returns true if the value is measured in bytes (most vmstat values are
* measured in pages). This defines the API part, the internal representation
* might be different.
*/
static __always_inline bool vmstat_item_in_bytes(int idx)
{
/*
* Global and per-node slab counters track slab pages.
* It's expected that changes are multiples of PAGE_SIZE.
* Internally values are stored in pages.
*
* Per-memcg and per-lruvec counters track memory, consumed
* by individual slab objects. These counters are actually
* byte-precise.
*/
return (idx == NR_SLAB_RECLAIMABLE_B ||
  idx == NR_SLAB_UNRECLAIMABLE_B);
}

/*
* We do arithmetic on the LRU lists in various places in the code,
* so it is important to keep the active lists LRU_ACTIVE higher in
* the array than the corresponding inactive lists, and to keep
* the *_FILE lists LRU_FILE higher than the corresponding _ANON lists.
*
* This has to be kept in sync with the statistics in zone_stat_item
* above and the descriptions in vmstat_text in mm/vmstat.c
*/
#define LRU_BASE 0
#define LRU_ACTIVE 1
#define LRU_FILE 2

enum lru_list {
LRU_INACTIVE_ANON = LRU_BASE,
LRU_ACTIVE_ANON = LRU_BASE + LRU_ACTIVE,
LRU_INACTIVE_FILE = LRU_BASE + LRU_FILE,
LRU_ACTIVE_FILE = LRU_BASE + LRU_FILE + LRU_ACTIVE,
LRU_UNEVICTABLE,
NR_LRU_LISTS
};

enum vmscan_throttle_state {
VMSCAN_THROTTLE_WRITEBACK,
VMSCAN_THROTTLE_ISOLATED,
VMSCAN_THROTTLE_NOPROGRESS,
VMSCAN_THROTTLE_CONGESTED,
NR_VMSCAN_THROTTLE,
};

#define for_each_lru(lru) for (lru = 0; lru < NR_LRU_LISTS; lru++)

#define for_each_evictable_lru(lru) for (lru = 0; lru <= LRU_ACTIVE_FILE; lru++)

static inline bool is_file_lru(enum lru_list lru)
{
return (lru == LRU_INACTIVE_FILE || lru == LRU_ACTIVE_FILE);
}

static inline bool is_active_lru(enum lru_list lru)
{
return (lru == LRU_ACTIVE_ANON || lru == LRU_ACTIVE_FILE);
}

#define WORKINGSET_ANON 0
#define WORKINGSET_FILE 1
#define ANON_AND_FILE 2

enum lruvec_flags {
/*
* An lruvec has many dirty pages backed by a congested BDI:
* 1. LRUVEC_CGROUP_CONGESTED is set by cgroup-level reclaim.
*    It can be cleared by cgroup reclaim or kswapd.
* 2. LRUVEC_NODE_CONGESTED is set by kswapd node-level reclaim.
*    It can only be cleared by kswapd.
*
* Essentially, kswapd can unthrottle an lruvec throttled by cgroup
* reclaim, but not vice versa. This only applies to the root cgroup.
* The goal is to prevent cgroup reclaim on the root cgroup (e.g.
* memory.reclaim) to unthrottle an unbalanced node (that was throttled
* by kswapd).
*/
LRUVEC_CGROUP_CONGESTED,
LRUVEC_NODE_CONGESTED,
};

#endif /* !__GENERATING_BOUNDS_H */

/*
* Evictable folios are divided into multiple generations. The youngest and the
* oldest generation numbers, max_seq and min_seq, are monotonically increasing.
* They form a sliding window of a variable size [MIN_NR_GENS, MAX_NR_GENS]. An
* offset within MAX_NR_GENS, i.e., gen, indexes the LRU list of the
* corresponding generation. The gen counter in folio->flags stores gen+1 while
* a folio is on one of lrugen->folios[]. Otherwise it stores 0.
*
* After a folio is faulted in, the aging needs to check the accessed bit at
* least twice before handing this folio over to the eviction. The first check
* clears the accessed bit from the initial fault; the second check makes sure
* this folio hasn't been used since then. This process, AKA second chance,
* requires a minimum of two generations, hence MIN_NR_GENS. And to maintain ABI
* compatibility with the active/inactive LRU, e.g., /proc/vmstat, these two
* generations are considered active; the rest of generations, if they exist,
* are considered inactive. See lru_gen_is_active().
*
* PG_active is always cleared while a folio is on one of lrugen->folios[] so
* that the sliding window needs not to worry about it. And it's set again when
* a folio considered active is isolated for non-reclaiming purposes, e.g.,
* migration. See lru_gen_add_folio() and lru_gen_del_folio().
*
* MAX_NR_GENS is set to 4 so that the multi-gen LRU can support twice the
* number of categories of the active/inactive LRU when keeping track of
* accesses through page tables. This requires order_base_2(MAX_NR_GENS+1) bits
* in folio->flags, masked by LRU_GEN_MASK.
*/
#define MIN_NR_GENS  2U
#define MAX_NR_GENS  4U

/*
* Each generation is divided into multiple tiers. A folio accessed N times
* through file descriptors is in tier order_base_2(N). A folio in the first
* tier (N=0,1) is marked by PG_referenced unless it was faulted in through page
* tables or read ahead. A folio in the last tier (MAX_NR_TIERS-1) is marked by
* PG_workingset. A folio in any other tier (1<N<5) between the first and last
* is marked by additional bits of LRU_REFS_WIDTH in folio->flags.
*
* In contrast to moving across generations which requires the LRU lock, moving
* across tiers only involves atomic operations on folio->flags and therefore
* has a negligible cost in the buffered access path. In the eviction path,
* comparisons of refaulted/(evicted+protected) from the first tier and the rest
* infer whether folios accessed multiple times through file descriptors are
* statistically hot and thus worth protecting.
*
* MAX_NR_TIERS is set to 4 so that the multi-gen LRU can support twice the
* number of categories of the active/inactive LRU when keeping track of
* accesses through file descriptors. This uses MAX_NR_TIERS-2 spare bits in
* folio->flags, masked by LRU_REFS_MASK.
*/
#define MAX_NR_TIERS  4U

#ifndef __GENERATING_BOUNDS_H

#define LRU_GEN_MASK  ((BIT(LRU_GEN_WIDTH) - 1) << LRU_GEN_PGOFF)
#define LRU_REFS_MASK  ((BIT(LRU_REFS_WIDTH) - 1) << LRU_REFS_PGOFF)

/*
* For folios accessed multiple times through file descriptors,
* lru_gen_inc_refs() sets additional bits of LRU_REFS_WIDTH in folio->flags
* after PG_referenced, then PG_workingset after LRU_REFS_WIDTH. After all its
* bits are set, i.e., LRU_REFS_FLAGS|BIT(PG_workingset), a folio is lazily
* promoted into the second oldest generation in the eviction path. And when
* folio_inc_gen() does that, it clears LRU_REFS_FLAGS so that
* lru_gen_inc_refs() can start over. Note that for this case, LRU_REFS_MASK is
* only valid when PG_referenced is set.
*
* For folios accessed multiple times through page tables, folio_update_gen()
* from a page table walk or lru_gen_set_refs() from a rmap walk sets
* PG_referenced after the accessed bit is cleared for the first time.
* Thereafter, those two paths set PG_workingset and promote folios to the
* youngest generation. Like folio_inc_gen(), folio_update_gen() also clears
* PG_referenced. Note that for this case, LRU_REFS_MASK is not used.
*
* For both cases above, after PG_workingset is set on a folio, it remains until
* this folio is either reclaimed, or "deactivated" by lru_gen_clear_refs(). It
* can be set again if lru_gen_test_recent() returns true upon a refault.
*/
#define LRU_REFS_FLAGS  (LRU_REFS_MASK | BIT(PG_referenced))

struct lruvec;
struct page_vma_mapped_walk;

#ifdef CONFIG_LRU_GEN

enum {
LRU_GEN_ANON,
LRU_GEN_FILE,
};

enum {
LRU_GEN_CORE,
LRU_GEN_MM_WALK,
LRU_GEN_NONLEAF_YOUNG,
NR_LRU_GEN_CAPS
};

#define MIN_LRU_BATCH  BITS_PER_LONG
#define MAX_LRU_BATCH  (MIN_LRU_BATCH * 64)

/* whether to keep historical stats from evicted generations */
#ifdef CONFIG_LRU_GEN_STATS
#define NR_HIST_GENS  MAX_NR_GENS
#else
#define NR_HIST_GENS  1U
#endif

/*
* The youngest generation number is stored in max_seq for both anon and file
* types as they are aged on an equal footing. The oldest generation numbers are
* stored in min_seq[] separately for anon and file types so that they can be
* incremented independently. Ideally min_seq[] are kept in sync when both anon
* and file types are evictable. However, to adapt to situations like extreme
* swappiness, they are allowed to be out of sync by at most
* MAX_NR_GENS-MIN_NR_GENS-1.
*
* The number of pages in each generation is eventually consistent and therefore
* can be transiently negative when reset_batch_size() is pending.
*/
struct lru_gen_folio {
/* the aging increments the youngest generation number */
unsigned long max_seq;
/* the eviction increments the oldest generation numbers */
unsigned long min_seq[ANON_AND_FILE];
/* the birth time of each generation in jiffies */
unsigned long timestamps[MAX_NR_GENS];
/* the multi-gen LRU lists, lazily sorted on eviction */
struct list_head folios[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES];
/* the multi-gen LRU sizes, eventually consistent */
long nr_pages[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES];
/* the exponential moving average of refaulted */
unsigned long avg_refaulted[ANON_AND_FILE][MAX_NR_TIERS];
/* the exponential moving average of evicted+protected */
unsigned long avg_total[ANON_AND_FILE][MAX_NR_TIERS];
/* can only be modified under the LRU lock */
unsigned long protected[NR_HIST_GENS][ANON_AND_FILE][MAX_NR_TIERS];
/* can be modified without holding the LRU lock */
atomic_long_t evicted[NR_HIST_GENS][ANON_AND_FILE][MAX_NR_TIERS];
atomic_long_t refaulted[NR_HIST_GENS][ANON_AND_FILE][MAX_NR_TIERS];
/* whether the multi-gen LRU is enabled */
bool enabled;
/* the memcg generation this lru_gen_folio belongs to */
u8 gen;
/* the list segment this lru_gen_folio belongs to */
u8 seg;
/* per-node lru_gen_folio list for global reclaim */
struct hlist_nulls_node list;
};

enum {
MM_LEAF_TOTAL,  /* total leaf entries */
MM_LEAF_YOUNG,  /* young leaf entries */
MM_NONLEAF_FOUND, /* non-leaf entries found in Bloom filters */
MM_NONLEAF_ADDED, /* non-leaf entries added to Bloom filters */
NR_MM_STATS
};

/* double-buffering Bloom filters */
#define NR_BLOOM_FILTERS 2

struct lru_gen_mm_state {
/* synced with max_seq after each iteration */
unsigned long seq;
/* where the current iteration continues after */
struct list_head *head;
/* where the last iteration ended before */
struct list_head *tail;
/* Bloom filters flip after each iteration */
unsigned long *filters[NR_BLOOM_FILTERS];
/* the mm stats for debugging */
unsigned long stats[NR_HIST_GENS][NR_MM_STATS];
};

struct lru_gen_mm_walk {
/* the lruvec under reclaim */
struct lruvec *lruvec;
/* max_seq from lru_gen_folio: can be out of date */
unsigned long seq;
/* the next address within an mm to scan */
unsigned long next_addr;
/* to batch promoted pages */
int nr_pages[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES];
/* to batch the mm stats */
int mm_stats[NR_MM_STATS];
/* total batched items */
int batched;
int swappiness;
bool force_scan;
};

/*
* For each node, memcgs are divided into two generations: the old and the
* young. For each generation, memcgs are randomly sharded into multiple bins
* to improve scalability. For each bin, the hlist_nulls is virtually divided
* into three segments: the head, the tail and the default.
*
* An onlining memcg is added to the tail of a random bin in the old generation.
* The eviction starts at the head of a random bin in the old generation. The
* per-node memcg generation counter, whose reminder (mod MEMCG_NR_GENS) indexes
* the old generation, is incremented when all its bins become empty.
*
* There are four operations:
* 1. MEMCG_LRU_HEAD, which moves a memcg to the head of a random bin in its
*    current generation (old or young) and updates its "seg" to "head";
* 2. MEMCG_LRU_TAIL, which moves a memcg to the tail of a random bin in its
*    current generation (old or young) and updates its "seg" to "tail";
* 3. MEMCG_LRU_OLD, which moves a memcg to the head of a random bin in the old
*    generation, updates its "gen" to "old" and resets its "seg" to "default";
* 4. MEMCG_LRU_YOUNG, which moves a memcg to the tail of a random bin in the
*    young generation, updates its "gen" to "young" and resets its "seg" to
*    "default".
*
* The events that trigger the above operations are:
* 1. Exceeding the soft limit, which triggers MEMCG_LRU_HEAD;
* 2. The first attempt to reclaim a memcg below low, which triggers
*    MEMCG_LRU_TAIL;
* 3. The first attempt to reclaim a memcg offlined or below reclaimable size
*    threshold, which triggers MEMCG_LRU_TAIL;
* 4. The second attempt to reclaim a memcg offlined or below reclaimable size
*    threshold, which triggers MEMCG_LRU_YOUNG;
* 5. Attempting to reclaim a memcg below min, which triggers MEMCG_LRU_YOUNG;
* 6. Finishing the aging on the eviction path, which triggers MEMCG_LRU_YOUNG;
* 7. Offlining a memcg, which triggers MEMCG_LRU_OLD.
*
* Notes:
* 1. Memcg LRU only applies to global reclaim, and the round-robin incrementing
*    of their max_seq counters ensures the eventual fairness to all eligible
*    memcgs. For memcg reclaim, it still relies on mem_cgroup_iter().
* 2. There are only two valid generations: old (seq) and young (seq+1).
*    MEMCG_NR_GENS is set to three so that when reading the generation counter
*    locklessly, a stale value (seq-1) does not wraparound to young.
*/
#define MEMCG_NR_GENS 3
#define MEMCG_NR_BINS 8

struct lru_gen_memcg {
/* the per-node memcg generation counter */
unsigned long seq;
/* each memcg has one lru_gen_folio per node */
unsigned long nr_memcgs[MEMCG_NR_GENS];
/* per-node lru_gen_folio list for global reclaim */
struct hlist_nulls_head fifo[MEMCG_NR_GENS][MEMCG_NR_BINS];
/* protects the above */
spinlock_t lock;
};

void lru_gen_init_pgdat(struct pglist_data *pgdat);
void lru_gen_init_lruvec(struct lruvec *lruvec);
bool lru_gen_look_around(struct page_vma_mapped_walk *pvmw);

void lru_gen_init_memcg(struct mem_cgroup *memcg);
void lru_gen_exit_memcg(struct mem_cgroup *memcg);
void lru_gen_online_memcg(struct mem_cgroup *memcg);
void lru_gen_offline_memcg(struct mem_cgroup *memcg);
void lru_gen_release_memcg(struct mem_cgroup *memcg);
void lru_gen_soft_reclaim(struct mem_cgroup *memcg, int nid);

#else /* !CONFIG_LRU_GEN */

static inline void lru_gen_init_pgdat(struct pglist_data *pgdat)
{
}

static inline void lru_gen_init_lruvec(struct lruvec *lruvec)
{
}

static inline bool lru_gen_look_around(struct page_vma_mapped_walk *pvmw)
{
return false;
}

static inline void lru_gen_init_memcg(struct mem_cgroup *memcg)
{
}

static inline void lru_gen_exit_memcg(struct mem_cgroup *memcg)
{
}

static inline void lru_gen_online_memcg(struct mem_cgroup *memcg)
{
}

static inline void lru_gen_offline_memcg(struct mem_cgroup *memcg)
{
}

static inline void lru_gen_release_memcg(struct mem_cgroup *memcg)
{
}

static inline void lru_gen_soft_reclaim(struct mem_cgroup *memcg, int nid)
{
}

#endif /* CONFIG_LRU_GEN */

struct lruvec {
struct list_head  lists[NR_LRU_LISTS];
/* per lruvec lru_lock for memcg */
spinlock_t   lru_lock;
/*
* These track the cost of reclaiming one LRU - file or anon -
* over the other. As the observed cost of reclaiming one LRU
* increases, the reclaim scan balance tips toward the other.
*/
unsigned long   anon_cost;
unsigned long   file_cost;
/* Non-resident age, driven by LRU movement */
atomic_long_t   nonresident_age;
/* Refaults at the time of last reclaim cycle */
unsigned long   refaults[ANON_AND_FILE];
/* Various lruvec state flags (enum lruvec_flags) */
unsigned long   flags;
#ifdef CONFIG_LRU_GEN
/* evictable pages divided into generations */
struct lru_gen_folio  lrugen;
#ifdef CONFIG_LRU_GEN_WALKS_MMU
/* to concurrently iterate lru_gen_mm_list */
struct lru_gen_mm_state  mm_state;
#endif
#endif /* CONFIG_LRU_GEN */
#ifdef CONFIG_MEMCG
struct pglist_data *pgdat;
#endif
struct zswap_lruvec_state zswap_lruvec_state;
};

/* Isolate for asynchronous migration */
#define ISOLATE_ASYNC_MIGRATE ((__force isolate_mode_t)0x4)
/* Isolate unevictable pages */
#define ISOLATE_UNEVICTABLE ((__force isolate_mode_t)0x8)

/* LRU Isolation modes. */
typedef unsigned __bitwise isolate_mode_t;

enum zone_watermarks {
WMARK_MIN,
WMARK_LOW,
WMARK_HIGH,
WMARK_PROMO,
NR_WMARK
};

/*
* One per migratetype for each PAGE_ALLOC_COSTLY_ORDER. Two additional lists
* are added for THP. One PCP list is used by GPF_MOVABLE, and the other PCP list
* is used by GFP_UNMOVABLE and GFP_RECLAIMABLE.
*/
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
#define NR_PCP_THP 2
#else
#define NR_PCP_THP 0
#endif
#define NR_LOWORDER_PCP_LISTS (MIGRATE_PCPTYPES * (PAGE_ALLOC_COSTLY_ORDER + 1))
#define NR_PCP_LISTS (NR_LOWORDER_PCP_LISTS + NR_PCP_THP)

/*
* Flags used in pcp->flags field.
*
* PCPF_PREV_FREE_HIGH_ORDER: a high-order page is freed in the
* previous page freeing.  To avoid to drain PCP for an accident
* high-order page freeing.
*
* PCPF_FREE_HIGH_BATCH: preserve "pcp->batch" pages in PCP before
* draining PCP for consecutive high-order pages freeing without
* allocation if data cache slice of CPU is large enough.  To reduce
* zone lock contention and keep cache-hot pages reusing.
*/
#define PCPF_PREV_FREE_HIGH_ORDER BIT(0)
#define PCPF_FREE_HIGH_BATCH  BIT(1)

struct per_cpu_pages {
spinlock_t lock; /* Protects lists field */
int count;  /* number of pages in the list */
int high;  /* high watermark, emptying needed */
int high_min;  /* min high watermark */
int high_max;  /* max high watermark */
int batch;  /* chunk size for buddy add/remove */
u8 flags;  /* protected by pcp->lock */
u8 alloc_factor; /* batch scaling factor during allocate */
#ifdef CONFIG_NUMA
u8 expire;  /* When 0, remote pagesets are drained */
#endif
short free_count; /* consecutive free count */

/* Lists of pages, one per migrate type stored on the pcp-lists */
struct list_head lists[NR_PCP_LISTS];
} ____cacheline_aligned_in_smp;

struct per_cpu_zonestat {
#ifdef CONFIG_SMP
s8 vm_stat_diff[NR_VM_ZONE_STAT_ITEMS];
s8 stat_threshold;
#endif
#ifdef CONFIG_NUMA
/*
* Low priority inaccurate counters that are only folded
* on demand. Use a large type to avoid the overhead of
* folding during refresh_cpu_vm_stats.
*/
unsigned long vm_numa_event[NR_VM_NUMA_EVENT_ITEMS];
#endif
};

struct per_cpu_nodestat {
s8 stat_threshold;
s8 vm_node_stat_diff[NR_VM_NODE_STAT_ITEMS];
};

#endif /* !__GENERATING_BOUNDS.H */

enum zone_type {
/*
* ZONE_DMA and ZONE_DMA32 are used when there are peripherals not able
* to DMA to all of the addressable memory (ZONE_NORMAL).
* On architectures where this area covers the whole 32 bit address
* space ZONE_DMA32 is used. ZONE_DMA is left for the ones with smaller
* DMA addressing constraints. This distinction is important as a 32bit
* DMA mask is assumed when ZONE_DMA32 is defined. Some 64-bit
* platforms may need both zones as they support peripherals with
* different DMA addressing limitations.
*/
#ifdef CONFIG_ZONE_DMA
ZONE_DMA,
#endif
#ifdef CONFIG_ZONE_DMA32
ZONE_DMA32,
#endif
/*
* Normal addressable memory is in ZONE_NORMAL. DMA operations can be
* performed on pages in ZONE_NORMAL if the DMA devices support
* transfers to all addressable memory.
*/
ZONE_NORMAL,
#ifdef CONFIG_HIGHMEM
/*
* A memory area that is only addressable by the kernel through
* mapping portions into its own address space. This is for example
* used by i386 to allow the kernel to address the memory beyond
* 900MB. The kernel will set up special mappings (page
* table entries on i386) for each page that the kernel needs to
* access.
*/
ZONE_HIGHMEM,
#endif
/*
* ZONE_MOVABLE is similar to ZONE_NORMAL, except that it contains
* movable pages with few exceptional cases described below. Main use
* cases for ZONE_MOVABLE are to make memory offlining/unplug more
* likely to succeed, and to locally limit unmovable allocations - e.g.,
* to increase the number of THP/huge pages. Notable special cases are:
*
* 1. Pinned pages: (long-term) pinning of movable pages might
*    essentially turn such pages unmovable. Therefore, we do not allow
*    pinning long-term pages in ZONE_MOVABLE. When pages are pinned and
*    faulted, they come from the right zone right away. However, it is
*    still possible that address space already has pages in
*    ZONE_MOVABLE at the time when pages are pinned (i.e. user has
*    touches that memory before pinning). In such case we migrate them
*    to a different zone. When migration fails - pinning fails.
* 2. memblock allocations: kernelcore/movablecore setups might create
*    situations where ZONE_MOVABLE contains unmovable allocations
*    after boot. Memory offlining and allocations fail early.
* 3. Memory holes: kernelcore/movablecore setups might create very rare
*    situations where ZONE_MOVABLE contains memory holes after boot,
*    for example, if we have sections that are only partially
*    populated. Memory offlining and allocations fail early.
* 4. PG_hwpoison pages: while poisoned pages can be skipped during
*    memory offlining, such pages cannot be allocated.
* 5. Unmovable PG_offline pages: in paravirtualized environments,
*    hotplugged memory blocks might only partially be managed by the
*    buddy (e.g., via XEN-balloon, Hyper-V balloon, virtio-mem). The
*    parts not manged by the buddy are unmovable PG_offline pages. In
*    some cases (virtio-mem), such pages can be skipped during
*    memory offlining, however, cannot be moved/allocated. These
*    techniques might use alloc_contig_range() to hide previously
*    exposed pages from the buddy again (e.g., to implement some sort
*    of memory unplug in virtio-mem).
* 6. ZERO_PAGE(0), kernelcore/movablecore setups might create
*    situations where ZERO_PAGE(0) which is allocated differently
*    on different platforms may end up in a movable zone. ZERO_PAGE(0)
*    cannot be migrated.
* 7. Memory-hotplug: when using memmap_on_memory and onlining the
*    memory to the MOVABLE zone, the vmemmap pages are also placed in
*    such zone. Such pages cannot be really moved around as they are
*    self-stored in the range, but they are treated as movable when
*    the range they describe is about to be offlined.
*
* In general, no unmovable allocations that degrade memory offlining
* should end up in ZONE_MOVABLE. Allocators (like alloc_contig_range())
* have to expect that migrating pages in ZONE_MOVABLE can fail (even
* if has_unmovable_pages() states that there are no unmovable pages,
* there can be false negatives).
*/
ZONE_MOVABLE,
#ifdef CONFIG_ZONE_DEVICE
ZONE_DEVICE,
#endif
__MAX_NR_ZONES

};

#ifndef __GENERATING_BOUNDS_H

#define ASYNC_AND_SYNC 2

struct zone {
/* Read-mostly fields */

/* zone watermarks, access with *_wmark_pages(zone) macros */
unsigned long _watermark[NR_WMARK];
unsigned long watermark_boost;

unsigned long nr_reserved_highatomic;
unsigned long nr_free_highatomic;

/*
* We don't know if the memory that we're going to allocate will be
* freeable or/and it will be released eventually, so to avoid totally
* wasting several GB of ram we must reserve some of the lower zone
* memory (otherwise we risk to run OOM on the lower zones despite
* there being tons of freeable ram on the higher zones).  This array is
* recalculated at runtime if the sysctl_lowmem_reserve_ratio sysctl
* changes.
*/
long lowmem_reserve[MAX_NR_ZONES];

#ifdef CONFIG_NUMA
int node;
#endif
struct pglist_data *zone_pgdat;
struct per_cpu_pages __percpu *per_cpu_pageset;
struct per_cpu_zonestat __percpu *per_cpu_zonestats;
/*
* the high and batch values are copied to individual pagesets for
* faster access
*/
int pageset_high_min;
int pageset_high_max;
int pageset_batch;

#ifndef CONFIG_SPARSEMEM
/*
* Flags for a pageblock_nr_pages block. See pageblock-flags.h.
* In SPARSEMEM, this map is stored in struct mem_section
*/
unsigned long  *pageblock_flags;
#endif /* CONFIG_SPARSEMEM */

/* zone_start_pfn == zone_start_paddr >> PAGE_SHIFT */
unsigned long  zone_start_pfn;

/*
* spanned_pages is the total pages spanned by the zone, including
* holes, which is calculated as:
* spanned_pages = zone_end_pfn - zone_start_pfn;
*
* present_pages is physical pages existing within the zone, which
* is calculated as:
* present_pages = spanned_pages - absent_pages(pages in holes);
*
* present_early_pages is present pages existing within the zone
* located on memory available since early boot, excluding hotplugged
* memory.
*
* managed_pages is present pages managed by the buddy system, which
* is calculated as (reserved_pages includes pages allocated by the
* bootmem allocator):
* managed_pages = present_pages - reserved_pages;
*
* cma pages is present pages that are assigned for CMA use
* (MIGRATE_CMA).
*
* So present_pages may be used by memory hotplug or memory power
* management logic to figure out unmanaged pages by checking
* (present_pages - managed_pages). And managed_pages should be used
* by page allocator and vm scanner to calculate all kinds of watermarks
* and thresholds.
*
* Locking rules:
*
* zone_start_pfn and spanned_pages are protected by span_seqlock.
* It is a seqlock because it has to be read outside of zone->lock,
* and it is done in the main allocator path.  But, it is written
* quite infrequently.
*
* The span_seq lock is declared along with zone->lock because it is
* frequently read in proximity to zone->lock.  It's good to
* give them a chance of being in the same cacheline.
*
* Write access to present_pages at runtime should be protected by
* mem_hotplug_begin/done(). Any reader who can't tolerant drift of
* present_pages should use get_online_mems() to get a stable value.
*/
atomic_long_t  managed_pages;
unsigned long  spanned_pages;
unsigned long  present_pages;
#if defined(CONFIG_MEMORY_HOTPLUG)
unsigned long  present_early_pages;
#endif
#ifdef CONFIG_CMA
unsigned long  cma_pages;
#endif

const char  *name;

#ifdef CONFIG_MEMORY_ISOLATION
/*
* Number of isolated pageblock. It is used to solve incorrect
* freepage counting problem due to racy retrieving migratetype
* of pageblock. Protected by zone->lock.
*/
unsigned long  nr_isolate_pageblock;
#endif

#ifdef CONFIG_MEMORY_HOTPLUG
/* see spanned/present_pages for more description */
seqlock_t  span_seqlock;
#endif

int initialized;

/* Write-intensive fields used from the page allocator */
CACHELINE_PADDING(_pad1_);

/* free areas of different sizes */
struct free_area free_area[NR_PAGE_ORDERS];

#ifdef CONFIG_UNACCEPTED_MEMORY
/* Pages to be accepted. All pages on the list are MAX_PAGE_ORDER */
struct list_head unaccepted_pages;

/* To be called once the last page in the zone is accepted */
struct work_struct unaccepted_cleanup;
#endif

/* zone flags, see below */
unsigned long  flags;

/* Primarily protects free_area */
spinlock_t  lock;

/* Pages to be freed when next trylock succeeds */
struct llist_head trylock_free_pages;

/* Write-intensive fields used by compaction and vmstats. */
CACHELINE_PADDING(_pad2_);

/*
* When free pages are below this point, additional steps are taken
* when reading the number of free pages to avoid per-cpu counter
* drift allowing watermarks to be breached
*/
unsigned long percpu_drift_mark;

#if defined CONFIG_COMPACTION || defined CONFIG_CMA
/* pfn where compaction free scanner should start */
unsigned long  compact_cached_free_pfn;
/* pfn where compaction migration scanner should start */
unsigned long  compact_cached_migrate_pfn[ASYNC_AND_SYNC];
unsigned long  compact_init_migrate_pfn;
unsigned long  compact_init_free_pfn;
#endif

#ifdef CONFIG_COMPACTION
/*
* On compaction failure, 1<<compact_defer_shift compactions
* are skipped before trying again. The number attempted since
* last failure is tracked with compact_considered.
* compact_order_failed is the minimum compaction failed order.
*/
unsigned int  compact_considered;
unsigned int  compact_defer_shift;
int   compact_order_failed;
#endif

#if defined CONFIG_COMPACTION || defined CONFIG_CMA
/* Set to true when the PG_migrate_skip bits should be cleared */
bool   compact_blockskip_flush;
#endif

bool   contiguous;

CACHELINE_PADDING(_pad3_);
/* Zone statistics */
atomic_long_t  vm_stat[NR_VM_ZONE_STAT_ITEMS];
atomic_long_t  vm_numa_event[NR_VM_NUMA_EVENT_ITEMS];
} ____cacheline_internodealigned_in_smp;

enum pgdat_flags {
PGDAT_DIRTY,   /* reclaim scanning has recently found
* many dirty file pages at the tail
* of the LRU.
*/
PGDAT_WRITEBACK,  /* reclaim scanning has recently found
* many pages under writeback
*/
PGDAT_RECLAIM_LOCKED,  /* prevents concurrent reclaim */
};

enum zone_flags {
ZONE_BOOSTED_WATERMARK,  /* zone recently boosted watermarks.
* Cleared when kswapd is woken.
*/
ZONE_RECLAIM_ACTIVE,  /* kswapd may be scanning the zone. */
ZONE_BELOW_HIGH,  /* zone is below high watermark. */
};

static inline unsigned long wmark_pages(const struct zone *z,
     enum zone_watermarks w)
{
return z->_watermark[w] + z->watermark_boost;
}

static inline unsigned long min_wmark_pages(const struct zone *z)
{
return wmark_pages(z, WMARK_MIN);
}

static inline unsigned long low_wmark_pages(const struct zone *z)
{
return wmark_pages(z, WMARK_LOW);
}

static inline unsigned long high_wmark_pages(const struct zone *z)
{
return wmark_pages(z, WMARK_HIGH);
}

static inline unsigned long promo_wmark_pages(const struct zone *z)
{
return wmark_pages(z, WMARK_PROMO);
}

static inline unsigned long zone_managed_pages(struct zone *zone)
{
return (unsigned long)atomic_long_read(&zone->managed_pages);
}

static inline unsigned long zone_cma_pages(struct zone *zone)
{
#ifdef CONFIG_CMA
return zone->cma_pages;
#else
return 0;
#endif
}

static inline unsigned long zone_end_pfn(const struct zone *zone)
{
return zone->zone_start_pfn + zone->spanned_pages;
}

static inline bool zone_spans_pfn(const struct zone *zone, unsigned long pfn)
{
return zone->zone_start_pfn <= pfn && pfn < zone_end_pfn(zone);
}

static inline bool zone_is_initialized(struct zone *zone)
{
return zone->initialized;
}

static inline bool zone_is_empty(struct zone *zone)
{
return zone->spanned_pages == 0;
}

#ifndef BUILD_VDSO32_64
/*
* The zone field is never updated after free_area_init_core()
* sets it, so none of the operations on it need to be atomic.
*/

/* Page flags: | [SECTION] | [NODE] | ZONE | [LAST_CPUPID] | ... | FLAGS | */
#define SECTIONS_PGOFF  ((sizeof(unsigned long)*8) - SECTIONS_WIDTH)
#define NODES_PGOFF  (SECTIONS_PGOFF - NODES_WIDTH)
#define ZONES_PGOFF  (NODES_PGOFF - ZONES_WIDTH)
#define LAST_CPUPID_PGOFF (ZONES_PGOFF - LAST_CPUPID_WIDTH)
#define KASAN_TAG_PGOFF  (LAST_CPUPID_PGOFF - KASAN_TAG_WIDTH)
#define LRU_GEN_PGOFF  (KASAN_TAG_PGOFF - LRU_GEN_WIDTH)
#define LRU_REFS_PGOFF  (LRU_GEN_PGOFF - LRU_REFS_WIDTH)

/*
* Define the bit shifts to access each section.  For non-existent
* sections we define the shift as 0; that plus a 0 mask ensures
* the compiler will optimise away reference to them.
*/
#define SECTIONS_PGSHIFT (SECTIONS_PGOFF * (SECTIONS_WIDTH != 0))
#define NODES_PGSHIFT  (NODES_PGOFF * (NODES_WIDTH != 0))
#define ZONES_PGSHIFT  (ZONES_PGOFF * (ZONES_WIDTH != 0))
#define LAST_CPUPID_PGSHIFT (LAST_CPUPID_PGOFF * (LAST_CPUPID_WIDTH != 0))
#define KASAN_TAG_PGSHIFT (KASAN_TAG_PGOFF * (KASAN_TAG_WIDTH != 0))

/* NODE:ZONE or SECTION:ZONE is used to ID a zone for the buddy allocator */
#ifdef NODE_NOT_IN_PAGE_FLAGS
#define ZONEID_SHIFT  (SECTIONS_SHIFT + ZONES_SHIFT)
#define ZONEID_PGOFF  ((SECTIONS_PGOFF < ZONES_PGOFF) ? \
      SECTIONS_PGOFF : ZONES_PGOFF)
#else
#define ZONEID_SHIFT  (NODES_SHIFT + ZONES_SHIFT)
#define ZONEID_PGOFF  ((NODES_PGOFF < ZONES_PGOFF) ? \
      NODES_PGOFF : ZONES_PGOFF)
#endif

#define ZONEID_PGSHIFT  (ZONEID_PGOFF * (ZONEID_SHIFT != 0))

#define ZONES_MASK  ((1UL << ZONES_WIDTH) - 1)
#define NODES_MASK  ((1UL << NODES_WIDTH) - 1)
#define SECTIONS_MASK  ((1UL << SECTIONS_WIDTH) - 1)
#define LAST_CPUPID_MASK ((1UL << LAST_CPUPID_SHIFT) - 1)
#define KASAN_TAG_MASK  ((1UL << KASAN_TAG_WIDTH) - 1)
#define ZONEID_MASK  ((1UL << ZONEID_SHIFT) - 1)

static inline enum zone_type page_zonenum(const struct page *page)
{
ASSERT_EXCLUSIVE_BITS(page->flags, ZONES_MASK << ZONES_PGSHIFT);
return (page->flags >> ZONES_PGSHIFT) & ZONES_MASK;
}

static inline enum zone_type folio_zonenum(const struct folio *folio)
{
return page_zonenum(&folio->page);
}

#ifdef CONFIG_ZONE_DEVICE
static inline bool is_zone_device_page(const struct page *page)
{
return page_zonenum(page) == ZONE_DEVICE;
}

static inline struct dev_pagemap *page_pgmap(const struct page *page)
{
VM_WARN_ON_ONCE_PAGE(!is_zone_device_page(page), page);
return page_folio(page)->pgmap;
}

/*
* Consecutive zone device pages should not be merged into the same sgl
* or bvec segment with other types of pages or if they belong to different
* pgmaps. Otherwise getting the pgmap of a given segment is not possible
* without scanning the entire segment. This helper returns true either if
* both pages are not zone device pages or both pages are zone device pages
* with the same pgmap.
*/
static inline bool zone_device_pages_have_same_pgmap(const struct page *a,
           const struct page *b)
{
if (is_zone_device_page(a) != is_zone_device_page(b))
  return false;
if (!is_zone_device_page(a))
  return true;
return page_pgmap(a) == page_pgmap(b);
}

extern void memmap_init_zone_device(struct zone *, unsigned long,
        unsigned long, struct dev_pagemap *);
#else
static inline bool is_zone_device_page(const struct page *page)
{
return false;
}
static inline bool zone_device_pages_have_same_pgmap(const struct page *a,
           const struct page *b)
{
return true;
}
static inline struct dev_pagemap *page_pgmap(const struct page *page)
{
return NULL;
}
#endif

static inline bool folio_is_zone_device(const struct folio *folio)
{
return is_zone_device_page(&folio->page);
}

static inline bool is_zone_movable_page(const struct page *page)
{
return page_zonenum(page) == ZONE_MOVABLE;
}

static inline bool folio_is_zone_movable(const struct folio *folio)
{
return folio_zonenum(folio) == ZONE_MOVABLE;
}
#endif

/*
* Return true if [start_pfn, start_pfn + nr_pages) range has a non-empty
* intersection with the given zone
*/
static inline bool zone_intersects(struct zone *zone,
  unsigned long start_pfn, unsigned long nr_pages)
{
if (zone_is_empty(zone))
  return false;
if (start_pfn >= zone_end_pfn(zone) ||
     start_pfn + nr_pages <= zone->zone_start_pfn)
  return false;

return true;
}

/*
* The "priority" of VM scanning is how much of the queues we will scan in one
* go. A value of 12 for DEF_PRIORITY implies that we will scan 1/4096th of the
* queues ("queue_length >> 12") during an aging round.
*/
#define DEF_PRIORITY 12

/* Maximum number of zones on a zonelist */
#define MAX_ZONES_PER_ZONELIST (MAX_NUMNODES * MAX_NR_ZONES)

enum {
ZONELIST_FALLBACK, /* zonelist with fallback */
#ifdef CONFIG_NUMA
/*
* The NUMA zonelists are doubled because we need zonelists that
* restrict the allocations to a single node for __GFP_THISNODE.
*/
ZONELIST_NOFALLBACK, /* zonelist without fallback (__GFP_THISNODE) */
#endif
MAX_ZONELISTS
};

/*
* This struct contains information about a zone in a zonelist. It is stored
* here to avoid dereferences into large structures and lookups of tables
*/
struct zoneref {
struct zone *zone; /* Pointer to actual zone */
int zone_idx;  /* zone_idx(zoneref->zone) */
};

/*
* One allocation request operates on a zonelist. A zonelist
* is a list of zones, the first one is the 'goal' of the
* allocation, the other zones are fallback zones, in decreasing
* priority.
*
* To speed the reading of the zonelist, the zonerefs contain the zone index
* of the entry being read. Helper functions to access information given
* a struct zoneref are
*
* zonelist_zone() - Return the struct zone * for an entry in _zonerefs
* zonelist_zone_idx() - Return the index of the zone for an entry
* zonelist_node_idx() - Return the index of the node for an entry
*/
struct zonelist {
struct zoneref _zonerefs[MAX_ZONES_PER_ZONELIST + 1];
};

/*
* The array of struct pages for flatmem.
* It must be declared for SPARSEMEM as well because there are configurations
* that rely on that.
*/
extern struct page *mem_map;

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
struct deferred_split {
spinlock_t split_queue_lock;
struct list_head split_queue;
unsigned long split_queue_len;
};
#endif

#ifdef CONFIG_MEMORY_FAILURE
/*
* Per NUMA node memory failure handling statistics.
*/
struct memory_failure_stats {
/*
* Number of raw pages poisoned.
* Cases not accounted: memory outside kernel control, offline page,
* arch-specific memory_failure (SGX), hwpoison_filter() filtered
* error events, and unpoison actions from hwpoison_unpoison.
*/
unsigned long total;
/*
* Recovery results of poisoned raw pages handled by memory_failure,
* in sync with mf_result.
* total = ignored + failed + delayed + recovered.
* total * PAGE_SIZE * #nodes = /proc/meminfo/HardwareCorrupted.
*/
unsigned long ignored;
unsigned long failed;
unsigned long delayed;
unsigned long recovered;
};
#endif

/*
* On NUMA machines, each NUMA node would have a pg_data_t to describe
* it's memory layout. On UMA machines there is a single pglist_data which
* describes the whole memory.
*
* Memory statistics and page replacement data structures are maintained on a
* per-zone basis.
*/
typedef struct pglist_data {
/*
* node_zones contains just the zones for THIS node. Not all of the
* zones may be populated, but it is the full list. It is referenced by
* this node's node_zonelists as well as other node's node_zonelists.
*/
struct zone node_zones[MAX_NR_ZONES];

/*
* node_zonelists contains references to all zones in all nodes.
* Generally the first zones will be references to this node's
* node_zones.
*/
struct zonelist node_zonelists[MAX_ZONELISTS];

int nr_zones; /* number of populated zones in this node */
#ifdef CONFIG_FLATMEM /* means !SPARSEMEM */
struct page *node_mem_map;
#ifdef CONFIG_PAGE_EXTENSION
struct page_ext *node_page_ext;
#endif
#endif
#if defined(CONFIG_MEMORY_HOTPLUG) || defined(CONFIG_DEFERRED_STRUCT_PAGE_INIT)
/*
* Must be held any time you expect node_start_pfn,
* node_present_pages, node_spanned_pages or nr_zones to stay constant.
* Also synchronizes pgdat->first_deferred_pfn during deferred page
* init.
*
* pgdat_resize_lock() and pgdat_resize_unlock() are provided to
* manipulate node_size_lock without checking for CONFIG_MEMORY_HOTPLUG
* or CONFIG_DEFERRED_STRUCT_PAGE_INIT.
*
* Nests above zone->lock and zone->span_seqlock
*/
spinlock_t node_size_lock;
#endif
unsigned long node_start_pfn;
unsigned long node_present_pages; /* total number of physical pages */
unsigned long node_spanned_pages; /* total size of physical page
     range, including holes */
int node_id;
wait_queue_head_t kswapd_wait;
wait_queue_head_t pfmemalloc_wait;

/* workqueues for throttling reclaim for different reasons. */
wait_queue_head_t reclaim_wait[NR_VMSCAN_THROTTLE];

atomic_t nr_writeback_throttled;/* nr of writeback-throttled tasks */
unsigned long nr_reclaim_start; /* nr pages written while throttled
* when throttling started. */
#ifdef CONFIG_MEMORY_HOTPLUG
struct mutex kswapd_lock;
#endif
struct task_struct *kswapd; /* Protected by kswapd_lock */
int kswapd_order;
enum zone_type kswapd_highest_zoneidx;

int kswapd_failures;  /* Number of 'reclaimed == 0' runs */

#ifdef CONFIG_COMPACTION
int kcompactd_max_order;
enum zone_type kcompactd_highest_zoneidx;
wait_queue_head_t kcompactd_wait;
struct task_struct *kcompactd;
bool proactive_compact_trigger;
#endif
/*
* This is a per-node reserve of pages that are not available
* to userspace allocations.
*/
unsigned long  totalreserve_pages;

#ifdef CONFIG_NUMA
/*
* node reclaim becomes active if more unmapped pages exist.
*/
unsigned long  min_unmapped_pages;
unsigned long  min_slab_pages;
#endif /* CONFIG_NUMA */

/* Write-intensive fields used by page reclaim */
CACHELINE_PADDING(_pad1_);

#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
/*
* If memory initialisation on large machines is deferred then this
* is the first PFN that needs to be initialised.
*/
unsigned long first_deferred_pfn;
#endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
struct deferred_split deferred_split_queue;
#endif

#ifdef CONFIG_NUMA_BALANCING
/* start time in ms of current promote rate limit period */
unsigned int nbp_rl_start;
/* number of promote candidate pages at start time of current rate limit period */
unsigned long nbp_rl_nr_cand;
/* promote threshold in ms */
unsigned int nbp_threshold;
/* start time in ms of current promote threshold adjustment period */
unsigned int nbp_th_start;
/*
* number of promote candidate pages at start time of current promote
* threshold adjustment period
*/
unsigned long nbp_th_nr_cand;
#endif
/* Fields commonly accessed by the page reclaim scanner */

/*
* NOTE: THIS IS UNUSED IF MEMCG IS ENABLED.
*
* Use mem_cgroup_lruvec() to look up lruvecs.
*/
struct lruvec  __lruvec;

unsigned long  flags;

#ifdef CONFIG_LRU_GEN
/* kswap mm walk data */
struct lru_gen_mm_walk mm_walk;
/* lru_gen_folio list */
struct lru_gen_memcg memcg_lru;
#endif

CACHELINE_PADDING(_pad2_);

/* Per-node vmstats */
struct per_cpu_nodestat __percpu *per_cpu_nodestats;
atomic_long_t  vm_stat[NR_VM_NODE_STAT_ITEMS];
#ifdef CONFIG_NUMA
struct memory_tier __rcu *memtier;
#endif
#ifdef CONFIG_MEMORY_FAILURE
struct memory_failure_stats mf_stats;
#endif
} pg_data_t;

#define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages)
#define node_spanned_pages(nid) (NODE_DATA(nid)->node_spanned_pages)

#define node_start_pfn(nid) (NODE_DATA(nid)->node_start_pfn)
#define node_end_pfn(nid) pgdat_end_pfn(NODE_DATA(nid))

static inline unsigned long pgdat_end_pfn(pg_data_t *pgdat)
{
return pgdat->node_start_pfn + pgdat->node_spanned_pages;
}

#include <linux/memory_hotplug.h>

void build_all_zonelists(pg_data_t *pgdat);
void wakeup_kswapd(struct zone *zone, gfp_t gfp_mask, int order,
     enum zone_type highest_zoneidx);
bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
    int highest_zoneidx, unsigned int alloc_flags,
    long free_pages);
bool zone_watermark_ok(struct zone *z, unsigned int order,
  unsigned long mark, int highest_zoneidx,
  unsigned int alloc_flags);
/*
* Memory initialization context, use to differentiate memory added by
* the platform statically or via memory hotplug interface.
*/
enum meminit_context {
MEMINIT_EARLY,
MEMINIT_HOTPLUG,
};

extern void init_currently_empty_zone(struct zone *zone, unsigned long start_pfn,
         unsigned long size);

extern void lruvec_init(struct lruvec *lruvec);

static inline struct pglist_data *lruvec_pgdat(struct lruvec *lruvec)
{
#ifdef CONFIG_MEMCG
return lruvec->pgdat;
#else
return container_of(lruvec, struct pglist_data, __lruvec);
#endif
}

#ifdef CONFIG_HAVE_MEMORYLESS_NODES
int local_memory_node(int node_id);
#else
static inline int local_memory_node(int node_id) { return node_id; };
#endif

/*
* zone_idx() returns 0 for the ZONE_DMA zone, 1 for the ZONE_NORMAL zone, etc.
*/
#define zone_idx(zone)  ((zone) - (zone)->zone_pgdat->node_zones)

#ifdef CONFIG_ZONE_DEVICE
static inline bool zone_is_zone_device(struct zone *zone)
{
return zone_idx(zone) == ZONE_DEVICE;
}
#else
static inline bool zone_is_zone_device(struct zone *zone)
{
return false;
}
#endif

/*
* Returns true if a zone has pages managed by the buddy allocator.
* All the reclaim decisions have to use this function rather than
* populated_zone(). If the whole zone is reserved then we can easily
* end up with populated_zone() && !managed_zone().
*/
static inline bool managed_zone(struct zone *zone)
{
return zone_managed_pages(zone);
}

/* Returns true if a zone has memory */
static inline bool populated_zone(struct zone *zone)
{
return zone->present_pages;
}

#ifdef CONFIG_NUMA
static inline int zone_to_nid(struct zone *zone)
{
return zone->node;
}

static inline void zone_set_nid(struct zone *zone, int nid)
{
zone->node = nid;
}
#else
static inline int zone_to_nid(struct zone *zone)
{
return 0;
}

static inline void zone_set_nid(struct zone *zone, int nid) {}
#endif

extern int movable_zone;

static inline int is_highmem_idx(enum zone_type idx)
{
#ifdef CONFIG_HIGHMEM
return (idx == ZONE_HIGHMEM ||
  (idx == ZONE_MOVABLE && movable_zone == ZONE_HIGHMEM));
#else
return 0;
#endif
}

/**
* is_highmem - helper function to quickly check if a struct zone is a
*              highmem zone or not.  This is an attempt to keep references
*              to ZONE_{DMA/NORMAL/HIGHMEM/etc} in general code to a minimum.
* @zone: pointer to struct zone variable
* Return: 1 for a highmem zone, 0 otherwise
*/
static inline int is_highmem(struct zone *zone)
{
return is_highmem_idx(zone_idx(zone));
}

#ifdef CONFIG_ZONE_DMA
bool has_managed_dma(void);
#else
static inline bool has_managed_dma(void)
{
return false;
}
#endif

#ifndef CONFIG_NUMA

extern struct pglist_data contig_page_data;
static inline struct pglist_data *NODE_DATA(int nid)
{
return &contig_page_data;
}

#else /* CONFIG_NUMA */

#include <asm/mmzone.h>

#endif /* !CONFIG_NUMA */

extern struct pglist_data *first_online_pgdat(void);
extern struct pglist_data *next_online_pgdat(struct pglist_data *pgdat);
extern struct zone *next_zone(struct zone *zone);

/**
* for_each_online_pgdat - helper macro to iterate over all online nodes
* @pgdat: pointer to a pg_data_t variable
*/
#define for_each_online_pgdat(pgdat)   \
for (pgdat = first_online_pgdat();  \
      pgdat;     \
      pgdat = next_online_pgdat(pgdat))
/**
* for_each_zone - helper macro to iterate over all memory zones
* @zone: pointer to struct zone variable
*
* The user only needs to declare the zone variable, for_each_zone
* fills it in.
*/
#define for_each_zone(zone)           \
for (zone = (first_online_pgdat())->node_zones; \
      zone;     \
      zone = next_zone(zone))

#define for_each_populated_zone(zone)          \
for (zone = (first_online_pgdat())->node_zones; \
      zone;     \
      zone = next_zone(zone))   \
  if (!populated_zone(zone))  \
   ; /* do nothing */ \
  else

static inline struct zone *zonelist_zone(struct zoneref *zoneref)
{
return zoneref->zone;
}

static inline int zonelist_zone_idx(struct zoneref *zoneref)
{
return zoneref->zone_idx;
}

static inline int zonelist_node_idx(struct zoneref *zoneref)
{
return zone_to_nid(zoneref->zone);
}

struct zoneref *__next_zones_zonelist(struct zoneref *z,
     enum zone_type highest_zoneidx,
     nodemask_t *nodes);

/**
* next_zones_zonelist - Returns the next zone at or below highest_zoneidx within the allowed nodemask using a cursor within a zonelist as a starting point
* @z: The cursor used as a starting point for the search
* @highest_zoneidx: The zone index of the highest zone to return
* @nodes: An optional nodemask to filter the zonelist with
*
* This function returns the next zone at or below a given zone index that is
* within the allowed nodemask using a cursor as the starting point for the
* search. The zoneref returned is a cursor that represents the current zone
* being examined. It should be advanced by one before calling
* next_zones_zonelist again.
*
* Return: the next zone at or below highest_zoneidx within the allowed
* nodemask using a cursor within a zonelist as a starting point
*/
static __always_inline struct zoneref *next_zones_zonelist(struct zoneref *z,
     enum zone_type highest_zoneidx,
     nodemask_t *nodes)
{
if (likely(!nodes && zonelist_zone_idx(z) <= highest_zoneidx))
  return z;
return __next_zones_zonelist(z, highest_zoneidx, nodes);
}

/**
* first_zones_zonelist - Returns the first zone at or below highest_zoneidx within the allowed nodemask in a zonelist
* @zonelist: The zonelist to search for a suitable zone
* @highest_zoneidx: The zone index of the highest zone to return
* @nodes: An optional nodemask to filter the zonelist with
*
* This function returns the first zone at or below a given zone index that is
* within the allowed nodemask. The zoneref returned is a cursor that can be
* used to iterate the zonelist with next_zones_zonelist by advancing it by
* one before calling.
*
* When no eligible zone is found, zoneref->zone is NULL (zoneref itself is
* never NULL). This may happen either genuinely, or due to concurrent nodemask
* update due to cpuset modification.
*
* Return: Zoneref pointer for the first suitable zone found
*/
static inline struct zoneref *first_zones_zonelist(struct zonelist *zonelist,
     enum zone_type highest_zoneidx,
     nodemask_t *nodes)
{
return next_zones_zonelist(zonelist->_zonerefs,
       highest_zoneidx, nodes);
}

/**
* for_each_zone_zonelist_nodemask - helper macro to iterate over valid zones in a zonelist at or below a given zone index and within a nodemask
* @zone: The current zone in the iterator
* @z: The current pointer within zonelist->_zonerefs being iterated
* @zlist: The zonelist being iterated
* @highidx: The zone index of the highest zone to return
* @nodemask: Nodemask allowed by the allocator
*
* This iterator iterates though all zones at or below a given zone index and
* within a given nodemask
*/
#define for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, nodemask) \
for (z = first_zones_zonelist(zlist, highidx, nodemask), zone = zonelist_zone(z); \
  zone;       \
  z = next_zones_zonelist(++z, highidx, nodemask), \
   zone = zonelist_zone(z))

#define for_next_zone_zonelist_nodemask(zone, z, highidx, nodemask) \
for (zone = zonelist_zone(z); \
  zone;       \
  z = next_zones_zonelist(++z, highidx, nodemask), \
   zone = zonelist_zone(z))

/**
* for_each_zone_zonelist - helper macro to iterate over valid zones in a zonelist at or below a given zone index
* @zone: The current zone in the iterator
* @z: The current pointer within zonelist->zones being iterated
* @zlist: The zonelist being iterated
* @highidx: The zone index of the highest zone to return
*
* This iterator iterates though all zones at or below a given zone index.
*/
#define for_each_zone_zonelist(zone, z, zlist, highidx) \
for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, NULL)

/* Whether the 'nodes' are all movable nodes */
static inline bool movable_only_nodes(nodemask_t *nodes)
{
struct zonelist *zonelist;
struct zoneref *z;
int nid;

if (nodes_empty(*nodes))
  return false;

/*
* We can chose arbitrary node from the nodemask to get a
* zonelist as they are interlinked. We just need to find
* at least one zone that can satisfy kernel allocations.
*/
nid = first_node(*nodes);
zonelist = &NODE_DATA(nid)->node_zonelists[ZONELIST_FALLBACK];
z = first_zones_zonelist(zonelist, ZONE_NORMAL, nodes);
return (!zonelist_zone(z)) ? true : false;
}

#ifdef CONFIG_SPARSEMEM
#include <asm/sparsemem.h>
#endif

#ifdef CONFIG_FLATMEM
#define pfn_to_nid(pfn)  (0)
#endif

#ifdef CONFIG_SPARSEMEM

/*
* PA_SECTION_SHIFT physical address to/from section number
* PFN_SECTION_SHIFT pfn to/from section number
*/
#define PA_SECTION_SHIFT (SECTION_SIZE_BITS)
#define PFN_SECTION_SHIFT (SECTION_SIZE_BITS - PAGE_SHIFT)

#define NR_MEM_SECTIONS  (1UL << SECTIONS_SHIFT)

#define PAGES_PER_SECTION       (1UL << PFN_SECTION_SHIFT)
#define PAGE_SECTION_MASK (~(PAGES_PER_SECTION-1))

#define SECTION_BLOCKFLAGS_BITS \
((1UL << (PFN_SECTION_SHIFT - pageblock_order)) * NR_PAGEBLOCK_BITS)

#if (MAX_PAGE_ORDER + PAGE_SHIFT) > SECTION_SIZE_BITS
#error Allocator MAX_PAGE_ORDER exceeds SECTION_SIZE
#endif

static inline unsigned long pfn_to_section_nr(unsigned long pfn)
{
return pfn >> PFN_SECTION_SHIFT;
}
static inline unsigned long section_nr_to_pfn(unsigned long sec)
{
return sec << PFN_SECTION_SHIFT;
}

#define SECTION_ALIGN_UP(pfn) (((pfn) + PAGES_PER_SECTION - 1) & PAGE_SECTION_MASK)
#define SECTION_ALIGN_DOWN(pfn) ((pfn) & PAGE_SECTION_MASK)

#define SUBSECTION_SHIFT 21
#define SUBSECTION_SIZE (1UL << SUBSECTION_SHIFT)

#define PFN_SUBSECTION_SHIFT (SUBSECTION_SHIFT - PAGE_SHIFT)
#define PAGES_PER_SUBSECTION (1UL << PFN_SUBSECTION_SHIFT)
#define PAGE_SUBSECTION_MASK (~(PAGES_PER_SUBSECTION-1))

#if SUBSECTION_SHIFT > SECTION_SIZE_BITS
#error Subsection size exceeds section size
#else
#define SUBSECTIONS_PER_SECTION (1UL << (SECTION_SIZE_BITS - SUBSECTION_SHIFT))
#endif

#define SUBSECTION_ALIGN_UP(pfn) ALIGN((pfn), PAGES_PER_SUBSECTION)
#define SUBSECTION_ALIGN_DOWN(pfn) ((pfn) & PAGE_SUBSECTION_MASK)

struct mem_section_usage {
struct rcu_head rcu;
#ifdef CONFIG_SPARSEMEM_VMEMMAP
DECLARE_BITMAP(subsection_map, SUBSECTIONS_PER_SECTION);
#endif
/* See declaration of similar field in struct zone */
unsigned long pageblock_flags[0];
};

void subsection_map_init(unsigned long pfn, unsigned long nr_pages);

struct page;
struct page_ext;
struct mem_section {
/*
* This is, logically, a pointer to an array of struct
* pages.  However, it is stored with some other magic.
* (see sparse.c::sparse_init_one_section())
*
* Additionally during early boot we encode node id of
* the location of the section here to guide allocation.
* (see sparse.c::memory_present())
*
* Making it a UL at least makes someone do a cast
* before using it wrong.
*/
unsigned long section_mem_map;

struct mem_section_usage *usage;
#ifdef CONFIG_PAGE_EXTENSION
/*
* If SPARSEMEM, pgdat doesn't have page_ext pointer. We use
* section. (see page_ext.h about this.)
*/
struct page_ext *page_ext;
unsigned long pad;
#endif
/*
* WARNING: mem_section must be a power-of-2 in size for the
* calculation and use of SECTION_ROOT_MASK to make sense.
*/
};

#ifdef CONFIG_SPARSEMEM_EXTREME
#define SECTIONS_PER_ROOT       (PAGE_SIZE / sizeof (struct mem_section))
#else
#define SECTIONS_PER_ROOT 1
#endif

#define SECTION_NR_TO_ROOT(sec) ((sec) / SECTIONS_PER_ROOT)
#define NR_SECTION_ROOTS DIV_ROUND_UP(NR_MEM_SECTIONS, SECTIONS_PER_ROOT)
#define SECTION_ROOT_MASK (SECTIONS_PER_ROOT - 1)

#ifdef CONFIG_SPARSEMEM_EXTREME
extern struct mem_section **mem_section;
#else
extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT];
#endif

static inline unsigned long *section_to_usemap(struct mem_section *ms)
{
return ms->usage->pageblock_flags;
}

static inline struct mem_section *__nr_to_section(unsigned long nr)
{
unsigned long root = SECTION_NR_TO_ROOT(nr);

if (unlikely(root >= NR_SECTION_ROOTS))
  return NULL;

#ifdef CONFIG_SPARSEMEM_EXTREME
if (!mem_section || !mem_section[root])
  return NULL;
#endif
return &mem_section[root][nr & SECTION_ROOT_MASK];
}
extern size_t mem_section_usage_size(void);

/*
* We use the lower bits of the mem_map pointer to store
* a little bit of information.  The pointer is calculated
* as mem_map - section_nr_to_pfn(pnum).  The result is
* aligned to the minimum alignment of the two values:
*   1. All mem_map arrays are page-aligned.
*   2. section_nr_to_pfn() always clears PFN_SECTION_SHIFT
*      lowest bits.  PFN_SECTION_SHIFT is arch-specific
*      (equal SECTION_SIZE_BITS - PAGE_SHIFT), and the
*      worst combination is powerpc with 256k pages,
*      which results in PFN_SECTION_SHIFT equal 6.
* To sum it up, at least 6 bits are available on all architectures.
* However, we can exceed 6 bits on some other architectures except
* powerpc (e.g. 15 bits are available on x86_64, 13 bits are available
* with the worst case of 64K pages on arm64) if we make sure the
* exceeded bit is not applicable to powerpc.
*/
enum {
SECTION_MARKED_PRESENT_BIT,
SECTION_HAS_MEM_MAP_BIT,
SECTION_IS_ONLINE_BIT,
SECTION_IS_EARLY_BIT,
#ifdef CONFIG_ZONE_DEVICE
SECTION_TAINT_ZONE_DEVICE_BIT,
#endif
#ifdef CONFIG_SPARSEMEM_VMEMMAP_PREINIT
SECTION_IS_VMEMMAP_PREINIT_BIT,
#endif
SECTION_MAP_LAST_BIT,
};

#define SECTION_MARKED_PRESENT  BIT(SECTION_MARKED_PRESENT_BIT)
#define SECTION_HAS_MEM_MAP  BIT(SECTION_HAS_MEM_MAP_BIT)
#define SECTION_IS_ONLINE  BIT(SECTION_IS_ONLINE_BIT)
#define SECTION_IS_EARLY  BIT(SECTION_IS_EARLY_BIT)
#ifdef CONFIG_ZONE_DEVICE
#define SECTION_TAINT_ZONE_DEVICE BIT(SECTION_TAINT_ZONE_DEVICE_BIT)
#endif
#ifdef CONFIG_SPARSEMEM_VMEMMAP_PREINIT
#define SECTION_IS_VMEMMAP_PREINIT BIT(SECTION_IS_VMEMMAP_PREINIT_BIT)
#endif
#define SECTION_MAP_MASK  (~(BIT(SECTION_MAP_LAST_BIT) - 1))
#define SECTION_NID_SHIFT  SECTION_MAP_LAST_BIT

static inline struct page *__section_mem_map_addr(struct mem_section *section)
{
unsigned long map = section->section_mem_map;
map &= SECTION_MAP_MASK;
return (struct page *)map;
}

static inline int present_section(struct mem_section *section)
{
return (section && (section->section_mem_map & SECTION_MARKED_PRESENT));
}

static inline int present_section_nr(unsigned long nr)
{
return present_section(__nr_to_section(nr));
}

static inline int valid_section(struct mem_section *section)
{
return (section && (section->section_mem_map & SECTION_HAS_MEM_MAP));
}

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