include/linux/mm_inline.h - third_party/kernel - Git at Google

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

 #include <linux/atomic.h>
 #include <linux/huge_mm.h>
 #include <linux/swap.h>
 #include <linux/string.h>
 #include <linux/userfaultfd_k.h>
 #include <linux/swapops.h>

 /**
  * folio_is_file_lru - Should the folio be on a file LRU or anon LRU?
  * @folio: The folio to test.
  *
  * We would like to get this info without a page flag, but the state
  * needs to survive until the folio is last deleted from the LRU, which
  * could be as far down as __page_cache_release.
  *
  * Return: An integer (not a boolean!) used to sort a folio onto the
  * right LRU list and to account folios correctly.
  * 1 if @folio is a regular filesystem backed page cache folio
  * or a lazily freed anonymous folio (e.g. via MADV_FREE).
  * 0 if @folio is a normal anonymous folio, a tmpfs folio or otherwise
  * ram or swap backed folio.
  */
 static inline int folio_is_file_lru(struct folio *folio)
 {
 	return !folio_test_swapbacked(folio);
 }

 static inline int page_is_file_lru(struct page *page)
 {
 	return folio_is_file_lru(page_folio(page));
 }

 static __always_inline void __update_lru_size(struct lruvec *lruvec,
 				enum lru_list lru, enum zone_type zid,
 				long nr_pages)
 {
 	struct pglist_data *pgdat = lruvec_pgdat(lruvec);

 	lockdep_assert_held(&lruvec->lru_lock);
 	WARN_ON_ONCE(nr_pages != (int)nr_pages);

 	__mod_lruvec_state(lruvec, NR_LRU_BASE + lru, nr_pages);
 	__mod_zone_page_state(&pgdat->node_zones[zid],
 				NR_ZONE_LRU_BASE + lru, nr_pages);
 }

 static __always_inline void update_lru_size(struct lruvec *lruvec,
 				enum lru_list lru, enum zone_type zid,
 				long nr_pages)
 {
 	__update_lru_size(lruvec, lru, zid, nr_pages);
 #ifdef CONFIG_MEMCG
 	mem_cgroup_update_lru_size(lruvec, lru, zid, nr_pages);
 #endif
 }

 /**
  * __folio_clear_lru_flags - Clear page lru flags before releasing a page.
  * @folio: The folio that was on lru and now has a zero reference.
  */
 static __always_inline void __folio_clear_lru_flags(struct folio *folio)
 {
 	VM_BUG_ON_FOLIO(!folio_test_lru(folio), folio);

 	__folio_clear_lru(folio);

 	/* this shouldn't happen, so leave the flags to bad_page() */
 	if (folio_test_active(folio) && folio_test_unevictable(folio))
 		return;

 	__folio_clear_active(folio);
 	__folio_clear_unevictable(folio);
 }

 /**
  * folio_lru_list - Which LRU list should a folio be on?
  * @folio: The folio to test.
  *
  * Return: The LRU list a folio should be on, as an index
  * into the array of LRU lists.
  */
 static __always_inline enum lru_list folio_lru_list(struct folio *folio)
 {
 	enum lru_list lru;

 	VM_BUG_ON_FOLIO(folio_test_active(folio) && folio_test_unevictable(folio), folio);

 	if (folio_test_unevictable(folio))
 		return LRU_UNEVICTABLE;

 	lru = folio_is_file_lru(folio) ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON;
 	if (folio_test_active(folio))
 		lru += LRU_ACTIVE;

 	return lru;
 }

 #ifdef CONFIG_LRU_GEN

 #ifdef CONFIG_LRU_GEN_ENABLED
 static inline bool lru_gen_enabled(void)
 {
 	DECLARE_STATIC_KEY_TRUE(lru_gen_caps[NR_LRU_GEN_CAPS]);

 	return static_branch_likely(&lru_gen_caps[LRU_GEN_CORE]);
 }
 #else
 static inline bool lru_gen_enabled(void)
 {
 	DECLARE_STATIC_KEY_FALSE(lru_gen_caps[NR_LRU_GEN_CAPS]);

 	return static_branch_unlikely(&lru_gen_caps[LRU_GEN_CORE]);
 }
 #endif

 static inline bool lru_gen_in_fault(void)
 {
 	return current->in_lru_fault;
 }

 static inline int lru_gen_from_seq(unsigned long seq)
 {
 	return seq % MAX_NR_GENS;
 }

 static inline int lru_hist_from_seq(unsigned long seq)
 {
 	return seq % NR_HIST_GENS;
 }

 static inline int lru_tier_from_refs(int refs)
 {
 	VM_WARN_ON_ONCE(refs > BIT(LRU_REFS_WIDTH));

 	/* see the comment in folio_lru_refs() */
 	return order_base_2(refs + 1);
 }

 static inline int folio_lru_refs(struct folio *folio)
 {
 	unsigned long flags = READ_ONCE(folio->flags);
 	bool workingset = flags & BIT(PG_workingset);

 	/*
 	 * Return the number of accesses beyond PG_referenced, i.e., N-1 if the
 	 * total number of accesses is N>1, since N=0,1 both map to the first
 	 * tier. lru_tier_from_refs() will account for this off-by-one. Also see
 	 * the comment on MAX_NR_TIERS.
 	 */
 	return ((flags & LRU_REFS_MASK) >> LRU_REFS_PGOFF) + workingset;
 }

 static inline int folio_lru_gen(struct folio *folio)
 {
 	unsigned long flags = READ_ONCE(folio->flags);

 	return ((flags & LRU_GEN_MASK) >> LRU_GEN_PGOFF) - 1;
 }

 static inline bool lru_gen_is_active(struct lruvec *lruvec, int gen)
 {
 	unsigned long max_seq = lruvec->lrugen.max_seq;

 	VM_WARN_ON_ONCE(gen >= MAX_NR_GENS);

 	/* see the comment on MIN_NR_GENS */
 	return gen == lru_gen_from_seq(max_seq) || gen == lru_gen_from_seq(max_seq - 1);
 }

 static inline void lru_gen_update_size(struct lruvec *lruvec, struct folio *folio,
 				       int old_gen, int new_gen)
 {
 	int type = folio_is_file_lru(folio);
 	int zone = folio_zonenum(folio);
 	int delta = folio_nr_pages(folio);
 	enum lru_list lru = type * LRU_INACTIVE_FILE;
 	struct lru_gen_folio *lrugen = &lruvec->lrugen;

 	VM_WARN_ON_ONCE(old_gen != -1 && old_gen >= MAX_NR_GENS);
 	VM_WARN_ON_ONCE(new_gen != -1 && new_gen >= MAX_NR_GENS);
 	VM_WARN_ON_ONCE(old_gen == -1 && new_gen == -1);

 	if (old_gen >= 0)
 		WRITE_ONCE(lrugen->nr_pages[old_gen][type][zone],
 			   lrugen->nr_pages[old_gen][type][zone] - delta);
 	if (new_gen >= 0)
 		WRITE_ONCE(lrugen->nr_pages[new_gen][type][zone],
 			   lrugen->nr_pages[new_gen][type][zone] + delta);

 	/* addition */
 	if (old_gen < 0) {
 		if (lru_gen_is_active(lruvec, new_gen))
 			lru += LRU_ACTIVE;
 		__update_lru_size(lruvec, lru, zone, delta);
 		return;
 	}

 	/* deletion */
 	if (new_gen < 0) {
 		if (lru_gen_is_active(lruvec, old_gen))
 			lru += LRU_ACTIVE;
 		__update_lru_size(lruvec, lru, zone, -delta);
 		return;
 	}

 	/* promotion */
 	if (!lru_gen_is_active(lruvec, old_gen) && lru_gen_is_active(lruvec, new_gen)) {
 		__update_lru_size(lruvec, lru, zone, -delta);
 		__update_lru_size(lruvec, lru + LRU_ACTIVE, zone, delta);
 	}

 	/* demotion requires isolation, e.g., lru_deactivate_fn() */
 	VM_WARN_ON_ONCE(lru_gen_is_active(lruvec, old_gen) && !lru_gen_is_active(lruvec, new_gen));
 }

 static inline bool lru_gen_add_folio(struct lruvec *lruvec, struct folio *folio, bool reclaiming)
 {
 	unsigned long seq;
 	unsigned long flags;
 	int gen = folio_lru_gen(folio);
 	int type = folio_is_file_lru(folio);
 	int zone = folio_zonenum(folio);
 	struct lru_gen_folio *lrugen = &lruvec->lrugen;

 	VM_WARN_ON_ONCE_FOLIO(gen != -1, folio);

 	if (folio_test_unevictable(folio) || !lrugen->enabled)
 		return false;
 	/*
 	 * There are four common cases for this page:
 	 * 1. If it's hot, i.e., freshly faulted in, add it to the youngest
 	 *    generation, and it's protected over the rest below.
 	 * 2. If it can't be evicted immediately, i.e., a dirty page pending
 	 *    writeback, add it to the second youngest generation.
 	 * 3. If it should be evicted first, e.g., cold and clean from
 	 *    folio_rotate_reclaimable(), add it to the oldest generation.
 	 * 4. Everything else falls between 2 & 3 above and is added to the
 	 *    second oldest generation if it's considered inactive, or the
 	 *    oldest generation otherwise. See lru_gen_is_active().
 	 */
 	if (folio_test_active(folio))
 		seq = lrugen->max_seq;
 	else if ((type == LRU_GEN_ANON && !folio_test_swapcache(folio)) ||
 		 (folio_test_reclaim(folio) &&
 		  (folio_test_dirty(folio) || folio_test_writeback(folio))))
 		seq = lrugen->max_seq - 1;
 	else if (reclaiming || lrugen->min_seq[type] + MIN_NR_GENS >= lrugen->max_seq)
 		seq = lrugen->min_seq[type];
 	else
 		seq = lrugen->min_seq[type] + 1;

 	gen = lru_gen_from_seq(seq);
 	flags = (gen + 1UL) << LRU_GEN_PGOFF;
 	/* see the comment on MIN_NR_GENS about PG_active */
 	set_mask_bits(&folio->flags, LRU_GEN_MASK | BIT(PG_active), flags);

 	lru_gen_update_size(lruvec, folio, -1, gen);
 	/* for folio_rotate_reclaimable() */
 	if (reclaiming)
 		list_add_tail(&folio->lru, &lrugen->folios[gen][type][zone]);
 	else
 		list_add(&folio->lru, &lrugen->folios[gen][type][zone]);

 	return true;
 }

 static inline bool lru_gen_del_folio(struct lruvec *lruvec, struct folio *folio, bool reclaiming)
 {
 	unsigned long flags;
 	int gen = folio_lru_gen(folio);

 	if (gen < 0)
 		return false;

 	VM_WARN_ON_ONCE_FOLIO(folio_test_active(folio), folio);
 	VM_WARN_ON_ONCE_FOLIO(folio_test_unevictable(folio), folio);

 	/* for folio_migrate_flags() */
 	flags = !reclaiming && lru_gen_is_active(lruvec, gen) ? BIT(PG_active) : 0;
 	flags = set_mask_bits(&folio->flags, LRU_GEN_MASK, flags);
 	gen = ((flags & LRU_GEN_MASK) >> LRU_GEN_PGOFF) - 1;

 	lru_gen_update_size(lruvec, folio, gen, -1);
 	list_del(&folio->lru);

 	return true;
 }

 #else /* !CONFIG_LRU_GEN */

 static inline bool lru_gen_enabled(void)
 {
 	return false;
 }

 static inline bool lru_gen_in_fault(void)
 {
 	return false;
 }

 static inline bool lru_gen_add_folio(struct lruvec *lruvec, struct folio *folio, bool reclaiming)
 {
 	return false;
 }

 static inline bool lru_gen_del_folio(struct lruvec *lruvec, struct folio *folio, bool reclaiming)
 {
 	return false;
 }

 #endif /* CONFIG_LRU_GEN */

 static __always_inline
 void lruvec_add_folio(struct lruvec *lruvec, struct folio *folio)
 {
 	enum lru_list lru = folio_lru_list(folio);

 	if (lru_gen_add_folio(lruvec, folio, false))
 		return;

 	update_lru_size(lruvec, lru, folio_zonenum(folio),
 			folio_nr_pages(folio));
 	if (lru != LRU_UNEVICTABLE)
 		list_add(&folio->lru, &lruvec->lists[lru]);
 }

 static __always_inline
 void lruvec_add_folio_tail(struct lruvec *lruvec, struct folio *folio)
 {
 	enum lru_list lru = folio_lru_list(folio);

 	if (lru_gen_add_folio(lruvec, folio, true))
 		return;

 	update_lru_size(lruvec, lru, folio_zonenum(folio),
 			folio_nr_pages(folio));
 	/* This is not expected to be used on LRU_UNEVICTABLE */
 	list_add_tail(&folio->lru, &lruvec->lists[lru]);
 }

 static __always_inline
 void lruvec_del_folio(struct lruvec *lruvec, struct folio *folio)
 {
 	enum lru_list lru = folio_lru_list(folio);

 	if (lru_gen_del_folio(lruvec, folio, false))
 		return;

 	if (lru != LRU_UNEVICTABLE)
 		list_del(&folio->lru);
 	update_lru_size(lruvec, lru, folio_zonenum(folio),
 			-folio_nr_pages(folio));
 }

 #ifdef CONFIG_ANON_VMA_NAME
 /*
  * mmap_lock should be read-locked when calling anon_vma_name(). Caller should
  * either keep holding the lock while using the returned pointer or it should
  * raise anon_vma_name refcount before releasing the lock.
  */
 extern struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma);
 extern struct anon_vma_name *anon_vma_name_alloc(const char *name);
 extern void anon_vma_name_free(struct kref *kref);

 /* mmap_lock should be read-locked */
 static inline void anon_vma_name_get(struct anon_vma_name *anon_name)
 {
 	if (anon_name)
 		kref_get(&anon_name->kref);
 }

 static inline void anon_vma_name_put(struct anon_vma_name *anon_name)
 {
 	if (anon_name)
 		kref_put(&anon_name->kref, anon_vma_name_free);
 }

 static inline
 struct anon_vma_name *anon_vma_name_reuse(struct anon_vma_name *anon_name)
 {
 	/* Prevent anon_name refcount saturation early on */
 	if (kref_read(&anon_name->kref) < REFCOUNT_MAX) {
 		anon_vma_name_get(anon_name);
 		return anon_name;

 	}
 	return anon_vma_name_alloc(anon_name->name);
 }

 static inline void dup_anon_vma_name(struct vm_area_struct *orig_vma,
 				     struct vm_area_struct *new_vma)
 {
 	struct anon_vma_name *anon_name = anon_vma_name(orig_vma);

 	if (anon_name)
 		new_vma->anon_name = anon_vma_name_reuse(anon_name);
 }

 static inline void free_anon_vma_name(struct vm_area_struct *vma)
 {
 	/*
 	 * Not using anon_vma_name because it generates a warning if mmap_lock
 	 * is not held, which might be the case here.
 	 */
 	anon_vma_name_put(vma->anon_name);
 }

 static inline bool anon_vma_name_eq(struct anon_vma_name *anon_name1,
 				    struct anon_vma_name *anon_name2)
 {
 	if (anon_name1 == anon_name2)
 		return true;

 	return anon_name1 && anon_name2 &&
 		!strcmp(anon_name1->name, anon_name2->name);
 }

 #else /* CONFIG_ANON_VMA_NAME */
 static inline struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma)
 {
 	return NULL;
 }

 static inline struct anon_vma_name *anon_vma_name_alloc(const char *name)
 {
 	return NULL;
 }

 static inline void anon_vma_name_get(struct anon_vma_name *anon_name) {}
 static inline void anon_vma_name_put(struct anon_vma_name *anon_name) {}
 static inline void dup_anon_vma_name(struct vm_area_struct *orig_vma,
 				     struct vm_area_struct *new_vma) {}
 static inline void free_anon_vma_name(struct vm_area_struct *vma) {}

 static inline bool anon_vma_name_eq(struct anon_vma_name *anon_name1,
 				    struct anon_vma_name *anon_name2)
 {
 	return true;
 }

 #endif  /* CONFIG_ANON_VMA_NAME */

 static inline void init_tlb_flush_pending(struct mm_struct *mm)
 {
 	atomic_set(&mm->tlb_flush_pending, 0);
 }

 static inline void inc_tlb_flush_pending(struct mm_struct *mm)
 {
 	atomic_inc(&mm->tlb_flush_pending);
 	/*
 	 * The only time this value is relevant is when there are indeed pages
 	 * to flush. And we'll only flush pages after changing them, which
 	 * requires the PTL.
 	 *
 	 * So the ordering here is:
 	 *
 	 *	atomic_inc(&mm->tlb_flush_pending);
 	 *	spin_lock(&ptl);
 	 *	...
 	 *	set_pte_at();
 	 *	spin_unlock(&ptl);
 	 *
 	 *				spin_lock(&ptl)
 	 *				mm_tlb_flush_pending();
 	 *				....
 	 *				spin_unlock(&ptl);
 	 *
 	 *	flush_tlb_range();
 	 *	atomic_dec(&mm->tlb_flush_pending);
 	 *
 	 * Where the increment if constrained by the PTL unlock, it thus
 	 * ensures that the increment is visible if the PTE modification is
 	 * visible. After all, if there is no PTE modification, nobody cares
 	 * about TLB flushes either.
 	 *
 	 * This very much relies on users (mm_tlb_flush_pending() and
 	 * mm_tlb_flush_nested()) only caring about _specific_ PTEs (and
 	 * therefore specific PTLs), because with SPLIT_PTE_PTLOCKS and RCpc
 	 * locks (PPC) the unlock of one doesn't order against the lock of
 	 * another PTL.
 	 *
 	 * The decrement is ordered by the flush_tlb_range(), such that
 	 * mm_tlb_flush_pending() will not return false unless all flushes have
 	 * completed.
 	 */
 }

 static inline void dec_tlb_flush_pending(struct mm_struct *mm)
 {
 	/*
 	 * See inc_tlb_flush_pending().
 	 *
 	 * This cannot be smp_mb__before_atomic() because smp_mb() simply does
 	 * not order against TLB invalidate completion, which is what we need.
 	 *
 	 * Therefore we must rely on tlb_flush_*() to guarantee order.
 	 */
 	atomic_dec(&mm->tlb_flush_pending);
 }

 static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
 {
 	/*
 	 * Must be called after having acquired the PTL; orders against that
 	 * PTLs release and therefore ensures that if we observe the modified
 	 * PTE we must also observe the increment from inc_tlb_flush_pending().
 	 *
 	 * That is, it only guarantees to return true if there is a flush
 	 * pending for _this_ PTL.
 	 */
 	return atomic_read(&mm->tlb_flush_pending);
 }

 static inline bool mm_tlb_flush_nested(struct mm_struct *mm)
 {
 	/*
 	 * Similar to mm_tlb_flush_pending(), we must have acquired the PTL
 	 * for which there is a TLB flush pending in order to guarantee
 	 * we've seen both that PTE modification and the increment.
 	 *
 	 * (no requirement on actually still holding the PTL, that is irrelevant)
 	 */
 	return atomic_read(&mm->tlb_flush_pending) > 1;
 }

 #ifdef CONFIG_MMU
 /*
  * Computes the pte marker to copy from the given source entry into dst_vma.
  * If no marker should be copied, returns 0.
  * The caller should insert a new pte created with make_pte_marker().
  */
 static inline pte_marker copy_pte_marker(
 		swp_entry_t entry, struct vm_area_struct *dst_vma)
 {
 	pte_marker srcm = pte_marker_get(entry);
 	/* Always copy error entries. */
 	pte_marker dstm = srcm & PTE_MARKER_POISONED;

 	/* Only copy PTE markers if UFFD register matches. */
 	if ((srcm & PTE_MARKER_UFFD_WP) && userfaultfd_wp(dst_vma))
 		dstm |= PTE_MARKER_UFFD_WP;

 	return dstm;
 }
 #endif

 /*
  * If this pte is wr-protected by uffd-wp in any form, arm the special pte to
  * replace a none pte.  NOTE!  This should only be called when *pte is already
  * cleared so we will never accidentally replace something valuable.  Meanwhile
  * none pte also means we are not demoting the pte so tlb flushed is not needed.
  * E.g., when pte cleared the caller should have taken care of the tlb flush.
  *
  * Must be called with pgtable lock held so that no thread will see the none
  * pte, and if they see it, they'll fault and serialize at the pgtable lock.
  *
  * This function is a no-op if PTE_MARKER_UFFD_WP is not enabled.
  */
 static inline void
 pte_install_uffd_wp_if_needed(struct vm_area_struct *vma, unsigned long addr,
 			      pte_t *pte, pte_t pteval)
 {
 #ifdef CONFIG_PTE_MARKER_UFFD_WP
 	bool arm_uffd_pte = false;

 	/* The current status of the pte should be "cleared" before calling */
 	WARN_ON_ONCE(!pte_none(ptep_get(pte)));

 	/*
 	 * NOTE: userfaultfd_wp_unpopulated() doesn't need this whole
 	 * thing, because when zapping either it means it's dropping the
 	 * page, or in TTU where the present pte will be quickly replaced
 	 * with a swap pte.  There's no way of leaking the bit.
 	 */
 	if (vma_is_anonymous(vma) || !userfaultfd_wp(vma))
 		return;

 	/* A uffd-wp wr-protected normal pte */
 	if (unlikely(pte_present(pteval) && pte_uffd_wp(pteval)))
 		arm_uffd_pte = true;

 	/*
 	 * A uffd-wp wr-protected swap pte.  Note: this should even cover an
 	 * existing pte marker with uffd-wp bit set.
 	 */
 	if (unlikely(pte_swp_uffd_wp_any(pteval)))
 		arm_uffd_pte = true;

 	if (unlikely(arm_uffd_pte))
 		set_pte_at(vma->vm_mm, addr, pte,
 			   make_pte_marker(PTE_MARKER_UFFD_WP));
 #endif
 }

 static inline bool vma_has_recency(struct vm_area_struct *vma)
 {
 	if (vma->vm_flags & (VM_SEQ_READ | VM_RAND_READ))
 		return false;

 	if (vma->vm_file && (vma->vm_file->f_mode & FMODE_NOREUSE))
 		return false;

 	return true;
 }

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

	#include <linux/atomic.h>
	#include <linux/huge_mm.h>
	#include <linux/swap.h>
	#include <linux/string.h>
	#include <linux/userfaultfd_k.h>
	#include <linux/swapops.h>

	/**
	* folio_is_file_lru - Should the folio be on a file LRU or anon LRU?
	* @folio: The folio to test.
	*
	* We would like to get this info without a page flag, but the state
	* needs to survive until the folio is last deleted from the LRU, which
	* could be as far down as __page_cache_release.
	*
	* Return: An integer (not a boolean!) used to sort a folio onto the
	* right LRU list and to account folios correctly.
	* 1 if @folio is a regular filesystem backed page cache folio
	* or a lazily freed anonymous folio (e.g. via MADV_FREE).
	* 0 if @folio is a normal anonymous folio, a tmpfs folio or otherwise
	* ram or swap backed folio.
	*/
	static inline int folio_is_file_lru(struct folio *folio)
	{
	return !folio_test_swapbacked(folio);
	}

	static inline int page_is_file_lru(struct page *page)
	{
	return folio_is_file_lru(page_folio(page));
	}

	static __always_inline void __update_lru_size(struct lruvec *lruvec,
	enum lru_list lru, enum zone_type zid,
	long nr_pages)
	{
	struct pglist_data *pgdat = lruvec_pgdat(lruvec);

	lockdep_assert_held(&lruvec->lru_lock);
	WARN_ON_ONCE(nr_pages != (int)nr_pages);

	__mod_lruvec_state(lruvec, NR_LRU_BASE + lru, nr_pages);
	__mod_zone_page_state(&pgdat->node_zones[zid],
	NR_ZONE_LRU_BASE + lru, nr_pages);
	}

	static __always_inline void update_lru_size(struct lruvec *lruvec,
	enum lru_list lru, enum zone_type zid,
	long nr_pages)
	{
	__update_lru_size(lruvec, lru, zid, nr_pages);
	#ifdef CONFIG_MEMCG
	mem_cgroup_update_lru_size(lruvec, lru, zid, nr_pages);
	#endif
	}

	/**
	* __folio_clear_lru_flags - Clear page lru flags before releasing a page.
	* @folio: The folio that was on lru and now has a zero reference.
	*/
	static __always_inline void __folio_clear_lru_flags(struct folio *folio)
	{
	VM_BUG_ON_FOLIO(!folio_test_lru(folio), folio);

	__folio_clear_lru(folio);

	/* this shouldn't happen, so leave the flags to bad_page() */
	if (folio_test_active(folio) && folio_test_unevictable(folio))
	return;

	__folio_clear_active(folio);
	__folio_clear_unevictable(folio);
	}

	/**
	* folio_lru_list - Which LRU list should a folio be on?
	* @folio: The folio to test.
	*
	* Return: The LRU list a folio should be on, as an index
	* into the array of LRU lists.
	*/
	static __always_inline enum lru_list folio_lru_list(struct folio *folio)
	{
	enum lru_list lru;

	VM_BUG_ON_FOLIO(folio_test_active(folio) && folio_test_unevictable(folio), folio);

	if (folio_test_unevictable(folio))
	return LRU_UNEVICTABLE;

	lru = folio_is_file_lru(folio) ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON;
	if (folio_test_active(folio))
	lru += LRU_ACTIVE;

	return lru;
	}

	#ifdef CONFIG_LRU_GEN

	#ifdef CONFIG_LRU_GEN_ENABLED
	static inline bool lru_gen_enabled(void)
	{
	DECLARE_STATIC_KEY_TRUE(lru_gen_caps[NR_LRU_GEN_CAPS]);

	return static_branch_likely(&lru_gen_caps[LRU_GEN_CORE]);
	}
	#else
	static inline bool lru_gen_enabled(void)
	{
	DECLARE_STATIC_KEY_FALSE(lru_gen_caps[NR_LRU_GEN_CAPS]);

	return static_branch_unlikely(&lru_gen_caps[LRU_GEN_CORE]);
	}
	#endif

	static inline bool lru_gen_in_fault(void)
	{
	return current->in_lru_fault;
	}

	static inline int lru_gen_from_seq(unsigned long seq)
	{
	return seq % MAX_NR_GENS;
	}

	static inline int lru_hist_from_seq(unsigned long seq)
	{
	return seq % NR_HIST_GENS;
	}

	static inline int lru_tier_from_refs(int refs)
	{
	VM_WARN_ON_ONCE(refs > BIT(LRU_REFS_WIDTH));

	/* see the comment in folio_lru_refs() */
	return order_base_2(refs + 1);
	}

	static inline int folio_lru_refs(struct folio *folio)
	{
	unsigned long flags = READ_ONCE(folio->flags);
	bool workingset = flags & BIT(PG_workingset);

	/*
	* Return the number of accesses beyond PG_referenced, i.e., N-1 if the
	* total number of accesses is N>1, since N=0,1 both map to the first
	* tier. lru_tier_from_refs() will account for this off-by-one. Also see
	* the comment on MAX_NR_TIERS.
	*/
	return ((flags & LRU_REFS_MASK) >> LRU_REFS_PGOFF) + workingset;
	}

	static inline int folio_lru_gen(struct folio *folio)
	{
	unsigned long flags = READ_ONCE(folio->flags);

	return ((flags & LRU_GEN_MASK) >> LRU_GEN_PGOFF) - 1;
	}

	static inline bool lru_gen_is_active(struct lruvec *lruvec, int gen)
	{
	unsigned long max_seq = lruvec->lrugen.max_seq;

	VM_WARN_ON_ONCE(gen >= MAX_NR_GENS);

	/* see the comment on MIN_NR_GENS */
	return gen == lru_gen_from_seq(max_seq) \|\| gen == lru_gen_from_seq(max_seq - 1);
	}

	static inline void lru_gen_update_size(struct lruvec lruvec, struct folio folio,
	int old_gen, int new_gen)
	{
	int type = folio_is_file_lru(folio);
	int zone = folio_zonenum(folio);
	int delta = folio_nr_pages(folio);
	enum lru_list lru = type * LRU_INACTIVE_FILE;
	struct lru_gen_folio *lrugen = &lruvec->lrugen;

	VM_WARN_ON_ONCE(old_gen != -1 && old_gen >= MAX_NR_GENS);
	VM_WARN_ON_ONCE(new_gen != -1 && new_gen >= MAX_NR_GENS);
	VM_WARN_ON_ONCE(old_gen == -1 && new_gen == -1);

	if (old_gen >= 0)
	WRITE_ONCE(lrugen->nr_pages[old_gen][type][zone],
	lrugen->nr_pages[old_gen][type][zone] - delta);
	if (new_gen >= 0)
	WRITE_ONCE(lrugen->nr_pages[new_gen][type][zone],
	lrugen->nr_pages[new_gen][type][zone] + delta);

	/* addition */
	if (old_gen < 0) {
	if (lru_gen_is_active(lruvec, new_gen))
	lru += LRU_ACTIVE;
	__update_lru_size(lruvec, lru, zone, delta);
	return;
	}

	/* deletion */
	if (new_gen < 0) {
	if (lru_gen_is_active(lruvec, old_gen))
	lru += LRU_ACTIVE;
	__update_lru_size(lruvec, lru, zone, -delta);
	return;
	}

	/* promotion */
	if (!lru_gen_is_active(lruvec, old_gen) && lru_gen_is_active(lruvec, new_gen)) {
	__update_lru_size(lruvec, lru, zone, -delta);
	__update_lru_size(lruvec, lru + LRU_ACTIVE, zone, delta);
	}

	/* demotion requires isolation, e.g., lru_deactivate_fn() */
	VM_WARN_ON_ONCE(lru_gen_is_active(lruvec, old_gen) && !lru_gen_is_active(lruvec, new_gen));
	}

	static inline bool lru_gen_add_folio(struct lruvec lruvec, struct folio folio, bool reclaiming)
	{
	unsigned long seq;
	unsigned long flags;
	int gen = folio_lru_gen(folio);
	int type = folio_is_file_lru(folio);
	int zone = folio_zonenum(folio);
	struct lru_gen_folio *lrugen = &lruvec->lrugen;

	VM_WARN_ON_ONCE_FOLIO(gen != -1, folio);

	if (folio_test_unevictable(folio) \|\| !lrugen->enabled)
	return false;
	/*
	* There are four common cases for this page:
	* 1. If it's hot, i.e., freshly faulted in, add it to the youngest
	* generation, and it's protected over the rest below.
	* 2. If it can't be evicted immediately, i.e., a dirty page pending
	* writeback, add it to the second youngest generation.
	* 3. If it should be evicted first, e.g., cold and clean from
	* folio_rotate_reclaimable(), add it to the oldest generation.
	* 4. Everything else falls between 2 & 3 above and is added to the
	* second oldest generation if it's considered inactive, or the
	* oldest generation otherwise. See lru_gen_is_active().
	*/
	if (folio_test_active(folio))
	seq = lrugen->max_seq;
	else if ((type == LRU_GEN_ANON && !folio_test_swapcache(folio)) \|\|
	(folio_test_reclaim(folio) &&
	(folio_test_dirty(folio) \|\| folio_test_writeback(folio))))
	seq = lrugen->max_seq - 1;
	else if (reclaiming \|\| lrugen->min_seq[type] + MIN_NR_GENS >= lrugen->max_seq)
	seq = lrugen->min_seq[type];
	else
	seq = lrugen->min_seq[type] + 1;

	gen = lru_gen_from_seq(seq);
	flags = (gen + 1UL) << LRU_GEN_PGOFF;
	/* see the comment on MIN_NR_GENS about PG_active */
	set_mask_bits(&folio->flags, LRU_GEN_MASK \| BIT(PG_active), flags);

	lru_gen_update_size(lruvec, folio, -1, gen);
	/* for folio_rotate_reclaimable() */
	if (reclaiming)
	list_add_tail(&folio->lru, &lrugen->folios[gen][type][zone]);
	else
	list_add(&folio->lru, &lrugen->folios[gen][type][zone]);

	return true;
	}

	static inline bool lru_gen_del_folio(struct lruvec lruvec, struct folio folio, bool reclaiming)
	{
	unsigned long flags;
	int gen = folio_lru_gen(folio);

	if (gen < 0)
	return false;

	VM_WARN_ON_ONCE_FOLIO(folio_test_active(folio), folio);
	VM_WARN_ON_ONCE_FOLIO(folio_test_unevictable(folio), folio);

	/* for folio_migrate_flags() */
	flags = !reclaiming && lru_gen_is_active(lruvec, gen) ? BIT(PG_active) : 0;
	flags = set_mask_bits(&folio->flags, LRU_GEN_MASK, flags);
	gen = ((flags & LRU_GEN_MASK) >> LRU_GEN_PGOFF) - 1;

	lru_gen_update_size(lruvec, folio, gen, -1);
	list_del(&folio->lru);

	return true;
	}

	#else /* !CONFIG_LRU_GEN */

	static inline bool lru_gen_enabled(void)
	{
	return false;
	}

	static inline bool lru_gen_in_fault(void)
	{
	return false;
	}

	static inline bool lru_gen_add_folio(struct lruvec lruvec, struct folio folio, bool reclaiming)
	{
	return false;
	}

	static inline bool lru_gen_del_folio(struct lruvec lruvec, struct folio folio, bool reclaiming)
	{
	return false;
	}

	#endif /* CONFIG_LRU_GEN */

	static __always_inline
	void lruvec_add_folio(struct lruvec lruvec, struct folio folio)
	{
	enum lru_list lru = folio_lru_list(folio);

	if (lru_gen_add_folio(lruvec, folio, false))
	return;

	update_lru_size(lruvec, lru, folio_zonenum(folio),
	folio_nr_pages(folio));
	if (lru != LRU_UNEVICTABLE)
	list_add(&folio->lru, &lruvec->lists[lru]);
	}

	static __always_inline
	void lruvec_add_folio_tail(struct lruvec lruvec, struct folio folio)
	{
	enum lru_list lru = folio_lru_list(folio);

	if (lru_gen_add_folio(lruvec, folio, true))
	return;

	update_lru_size(lruvec, lru, folio_zonenum(folio),
	folio_nr_pages(folio));
	/* This is not expected to be used on LRU_UNEVICTABLE */
	list_add_tail(&folio->lru, &lruvec->lists[lru]);
	}

	static __always_inline
	void lruvec_del_folio(struct lruvec lruvec, struct folio folio)
	{
	enum lru_list lru = folio_lru_list(folio);

	if (lru_gen_del_folio(lruvec, folio, false))
	return;

	if (lru != LRU_UNEVICTABLE)
	list_del(&folio->lru);
	update_lru_size(lruvec, lru, folio_zonenum(folio),
	-folio_nr_pages(folio));
	}

	#ifdef CONFIG_ANON_VMA_NAME
	/*
	* mmap_lock should be read-locked when calling anon_vma_name(). Caller should
	* either keep holding the lock while using the returned pointer or it should
	* raise anon_vma_name refcount before releasing the lock.
	*/
	extern struct anon_vma_name anon_vma_name(struct vm_area_struct vma);
	extern struct anon_vma_name anon_vma_name_alloc(const char name);
	extern void anon_vma_name_free(struct kref *kref);

	/* mmap_lock should be read-locked */
	static inline void anon_vma_name_get(struct anon_vma_name *anon_name)
	{
	if (anon_name)
	kref_get(&anon_name->kref);
	}

	static inline void anon_vma_name_put(struct anon_vma_name *anon_name)
	{
	if (anon_name)
	kref_put(&anon_name->kref, anon_vma_name_free);
	}

	static inline
	struct anon_vma_name anon_vma_name_reuse(struct anon_vma_name anon_name)
	{
	/* Prevent anon_name refcount saturation early on */
	if (kref_read(&anon_name->kref) < REFCOUNT_MAX) {
	anon_vma_name_get(anon_name);
	return anon_name;

	}
	return anon_vma_name_alloc(anon_name->name);
	}

	static inline void dup_anon_vma_name(struct vm_area_struct *orig_vma,
	struct vm_area_struct *new_vma)
	{
	struct anon_vma_name *anon_name = anon_vma_name(orig_vma);

	if (anon_name)
	new_vma->anon_name = anon_vma_name_reuse(anon_name);
	}

	static inline void free_anon_vma_name(struct vm_area_struct *vma)
	{
	/*
	* Not using anon_vma_name because it generates a warning if mmap_lock
	* is not held, which might be the case here.
	*/
	anon_vma_name_put(vma->anon_name);
	}

	static inline bool anon_vma_name_eq(struct anon_vma_name *anon_name1,
	struct anon_vma_name *anon_name2)
	{
	if (anon_name1 == anon_name2)
	return true;

	return anon_name1 && anon_name2 &&
	!strcmp(anon_name1->name, anon_name2->name);
	}

	#else /* CONFIG_ANON_VMA_NAME */
	static inline struct anon_vma_name anon_vma_name(struct vm_area_struct vma)
	{
	return NULL;
	}

	static inline struct anon_vma_name anon_vma_name_alloc(const char name)
	{
	return NULL;
	}

	static inline void anon_vma_name_get(struct anon_vma_name *anon_name) {}
	static inline void anon_vma_name_put(struct anon_vma_name *anon_name) {}
	static inline void dup_anon_vma_name(struct vm_area_struct *orig_vma,
	struct vm_area_struct *new_vma) {}
	static inline void free_anon_vma_name(struct vm_area_struct *vma) {}

	static inline bool anon_vma_name_eq(struct anon_vma_name *anon_name1,
	struct anon_vma_name *anon_name2)
	{
	return true;
	}

	#endif /* CONFIG_ANON_VMA_NAME */

	static inline void init_tlb_flush_pending(struct mm_struct *mm)
	{
	atomic_set(&mm->tlb_flush_pending, 0);
	}

	static inline void inc_tlb_flush_pending(struct mm_struct *mm)
	{
	atomic_inc(&mm->tlb_flush_pending);
	/*
	* The only time this value is relevant is when there are indeed pages
	* to flush. And we'll only flush pages after changing them, which
	* requires the PTL.
	*
	* So the ordering here is:
	*
	* atomic_inc(&mm->tlb_flush_pending);
	* spin_lock(&ptl);
	* ...
	* set_pte_at();
	* spin_unlock(&ptl);
	*
	* spin_lock(&ptl)
	* mm_tlb_flush_pending();
	* ....
	* spin_unlock(&ptl);
	*
	* flush_tlb_range();
	* atomic_dec(&mm->tlb_flush_pending);
	*
	* Where the increment if constrained by the PTL unlock, it thus
	* ensures that the increment is visible if the PTE modification is
	* visible. After all, if there is no PTE modification, nobody cares
	* about TLB flushes either.
	*
	* This very much relies on users (mm_tlb_flush_pending() and
	* mm_tlb_flush_nested()) only caring about _specific_ PTEs (and
	* therefore specific PTLs), because with SPLIT_PTE_PTLOCKS and RCpc
	* locks (PPC) the unlock of one doesn't order against the lock of
	* another PTL.
	*
	* The decrement is ordered by the flush_tlb_range(), such that
	* mm_tlb_flush_pending() will not return false unless all flushes have
	* completed.
	*/
	}

	static inline void dec_tlb_flush_pending(struct mm_struct *mm)
	{
	/*
	* See inc_tlb_flush_pending().
	*
	* This cannot be smp_mb__before_atomic() because smp_mb() simply does
	* not order against TLB invalidate completion, which is what we need.
	*
	* Therefore we must rely on tlb_flush_*() to guarantee order.
	*/
	atomic_dec(&mm->tlb_flush_pending);
	}

	static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
	{
	/*
	* Must be called after having acquired the PTL; orders against that
	* PTLs release and therefore ensures that if we observe the modified
	* PTE we must also observe the increment from inc_tlb_flush_pending().
	*
	* That is, it only guarantees to return true if there is a flush
	* pending for _this_ PTL.
	*/
	return atomic_read(&mm->tlb_flush_pending);
	}

	static inline bool mm_tlb_flush_nested(struct mm_struct *mm)
	{
	/*
	* Similar to mm_tlb_flush_pending(), we must have acquired the PTL
	* for which there is a TLB flush pending in order to guarantee
	* we've seen both that PTE modification and the increment.
	*
	* (no requirement on actually still holding the PTL, that is irrelevant)
	*/
	return atomic_read(&mm->tlb_flush_pending) > 1;
	}

	#ifdef CONFIG_MMU
	/*
	* Computes the pte marker to copy from the given source entry into dst_vma.
	* If no marker should be copied, returns 0.
	* The caller should insert a new pte created with make_pte_marker().
	*/
	static inline pte_marker copy_pte_marker(
	swp_entry_t entry, struct vm_area_struct *dst_vma)
	{
	pte_marker srcm = pte_marker_get(entry);
	/* Always copy error entries. */
	pte_marker dstm = srcm & PTE_MARKER_POISONED;

	/* Only copy PTE markers if UFFD register matches. */
	if ((srcm & PTE_MARKER_UFFD_WP) && userfaultfd_wp(dst_vma))
	dstm \|= PTE_MARKER_UFFD_WP;

	return dstm;
	}
	#endif

	/*
	* If this pte is wr-protected by uffd-wp in any form, arm the special pte to
	* replace a none pte. NOTE! This should only be called when *pte is already
	* cleared so we will never accidentally replace something valuable. Meanwhile
	* none pte also means we are not demoting the pte so tlb flushed is not needed.
	* E.g., when pte cleared the caller should have taken care of the tlb flush.
	*
	* Must be called with pgtable lock held so that no thread will see the none
	* pte, and if they see it, they'll fault and serialize at the pgtable lock.
	*
	* This function is a no-op if PTE_MARKER_UFFD_WP is not enabled.
	*/
	static inline void
	pte_install_uffd_wp_if_needed(struct vm_area_struct *vma, unsigned long addr,
	pte_t *pte, pte_t pteval)
	{
	#ifdef CONFIG_PTE_MARKER_UFFD_WP
	bool arm_uffd_pte = false;

	/* The current status of the pte should be "cleared" before calling */
	WARN_ON_ONCE(!pte_none(ptep_get(pte)));

	/*
	* NOTE: userfaultfd_wp_unpopulated() doesn't need this whole
	* thing, because when zapping either it means it's dropping the
	* page, or in TTU where the present pte will be quickly replaced
	* with a swap pte. There's no way of leaking the bit.
	*/
	if (vma_is_anonymous(vma) \|\| !userfaultfd_wp(vma))
	return;

	/* A uffd-wp wr-protected normal pte */
	if (unlikely(pte_present(pteval) && pte_uffd_wp(pteval)))
	arm_uffd_pte = true;

	/*
	* A uffd-wp wr-protected swap pte. Note: this should even cover an
	* existing pte marker with uffd-wp bit set.
	*/
	if (unlikely(pte_swp_uffd_wp_any(pteval)))
	arm_uffd_pte = true;

	if (unlikely(arm_uffd_pte))
	set_pte_at(vma->vm_mm, addr, pte,
	make_pte_marker(PTE_MARKER_UFFD_WP));
	#endif
	}

	static inline bool vma_has_recency(struct vm_area_struct *vma)
	{
	if (vma->vm_flags & (VM_SEQ_READ \| VM_RAND_READ))
	return false;

	if (vma->vm_file && (vma->vm_file->f_mode & FMODE_NOREUSE))
	return false;

	return true;
	}

	#endif