[PATCH] mm: move folio LRU helpers out of swap

[Jianyue Wu <wujianyue000@gmail.com>]

All allocated folios are added into lru lists for later reclaim whether
they are file or anonymous folios. However those folio lru operation codes
are put in mm/swap.c which is not so appropriate. Because swap code is
only for anonymous folios.

Here move folio lru helpers out of mm/swap.c and put them into file for
their own.

This is cleanup, no functional change involved.

Signed-off-by: Jianyue Wu <wujianyue000@gmail.com>
---
 MAINTAINERS          |    2 +
 include/linux/mm.h   |    2 +
 include/linux/swap.h |   38 --
 mm/Makefile          |    2 +-
 mm/folio_lru.c       | 1074 ++++++++++++++++++++++++++++++++++++++++++
 mm/folio_lru.h       |   53 +++
 mm/swap.c            | 1064 +----------------------------------------
 7 files changed, 1133 insertions(+), 1102 deletions(-)
 create mode 100644 mm/folio_lru.c
 create mode 100644 mm/folio_lru.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 77fdfcb55f06..7dc04858de66 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16867,6 +16867,8 @@ R:	Shakeel Butt <shakeel.butt@linux.dev>
 R:	Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
 L:	linux-mm@kvack.org
 S:	Maintained
+F:	mm/folio_lru.c
+F:	mm/folio_lru.h
 F:	mm/vmscan.c
 F:	mm/workingset.c

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 5be3d8a8f806..8cb54a5f47c1 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -39,6 +39,8 @@
 #include <linux/bitops.h>
 #include <linux/iommu-debug-pagealloc.h>

+#include "../../mm/folio_lru.h"
+
 struct mempolicy;
 struct anon_vma;
 struct anon_vma_chain;
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 62fc7499b408..4de5e441576c 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -327,44 +327,6 @@ extern unsigned long totalreserve_pages;


 /* linux/mm/swap.c */
-void lru_note_cost_unlock_irq(struct lruvec *lruvec, bool file,
-		unsigned int nr_io, unsigned int nr_rotated)
-		__releases(lruvec->lru_lock);
-void lru_note_cost_refault(struct folio *);
-void folio_add_lru(struct folio *);
-void folio_add_lru_vma(struct folio *, struct vm_area_struct *);
-void mark_page_accessed(struct page *);
-void folio_mark_accessed(struct folio *);
-
-static inline bool folio_may_be_lru_cached(struct folio *folio)
-{
-	/*
-	 * Holding PMD-sized folios in per-CPU LRU cache unbalances accounting.
-	 * Holding small numbers of low-order mTHP folios in per-CPU LRU cache
-	 * will be sensible, but nobody has implemented and tested that yet.
-	 */
-	return !folio_test_large(folio);
-}
-
-extern atomic_t lru_disable_count;
-
-static inline bool lru_cache_disabled(void)
-{
-	return atomic_read(&lru_disable_count);
-}
-
-static inline void lru_cache_enable(void)
-{
-	atomic_dec(&lru_disable_count);
-}
-
-extern void lru_cache_disable(void);
-extern void lru_add_drain(void);
-extern void lru_add_drain_cpu(int cpu);
-extern void lru_add_drain_cpu_zone(struct zone *zone);
-extern void lru_add_drain_all(void);
-void folio_deactivate(struct folio *folio);
-void folio_mark_lazyfree(struct folio *folio);
 extern void swap_setup(void);

 /* linux/mm/vmscan.c */
diff --git a/mm/Makefile b/mm/Makefile
index 8ad2ab08244e..f2e31f2dd3ff 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -50,7 +50,7 @@ endif

 obj-y			:= filemap.o mempool.o oom_kill.o fadvise.o \
 			   maccess.o page-writeback.o folio-compat.o \
-			   readahead.o swap.o truncate.o vmscan.o shrinker.o \
+			   readahead.o folio_lru.o swap.o truncate.o vmscan.o shrinker.o \
 			   shmem.o util.o mmzone.o vmstat.o backing-dev.o \
 			   mm_init.o percpu.o slab_common.o \
 			   compaction.o show_mem.o \
diff --git a/mm/folio_lru.c b/mm/folio_lru.c
new file mode 100644
index 000000000000..ec41a5d59ab0
--- /dev/null
+++ b/mm/folio_lru.c
@@ -0,0 +1,1074 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Folio LRU helpers: entry, motion, and exit from the VM LRU machinery.
+ */
+
+/*
+ * These helpers sit at the seam where a folio enters, moves inside,
+ * or leaves the VM's LRU machinery.  Letting them live beside reclaim
+ * logic keeps swap.c from carrying stories that were never about swap.
+ */
+
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/kernel_stat.h>
+#include <linux/swap.h>
+#include <linux/mman.h>
+#include <linux/pagemap.h>
+#include <linux/pagevec.h>
+#include <linux/export.h>
+#include <linux/mm_inline.h>
+#include <linux/memremap.h>
+#include <linux/percpu.h>
+#include <linux/cpu.h>
+#include <linux/backing-dev.h>
+#include <linux/memcontrol.h>
+#include <linux/hugetlb.h>
+#include <linux/page_idle.h>
+#include <linux/local_lock.h>
+#include <linux/buffer_head.h>
+
+#include "internal.h"
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/pagemap.h>
+
+struct cpu_fbatches {
+	/*
+	 * The following folio batches are grouped together because they are protected
+	 * by disabling preemption (and interrupts remain enabled).
+	 */
+	local_lock_t lock;
+	struct folio_batch lru_add;
+	struct folio_batch lru_deactivate_file;
+	struct folio_batch lru_deactivate;
+	struct folio_batch lru_lazyfree;
+#ifdef CONFIG_SMP
+	struct folio_batch lru_activate;
+#endif
+	/* Protecting the following batches which require disabling interrupts */
+	local_lock_t lock_irq;
+	struct folio_batch lru_move_tail;
+};
+
+static DEFINE_PER_CPU(struct cpu_fbatches, cpu_fbatches) = {
+	.lock = INIT_LOCAL_LOCK(lock),
+	.lock_irq = INIT_LOCAL_LOCK(lock_irq),
+};
+
+static void __page_cache_release(struct folio *folio, struct lruvec **lruvecp,
+		unsigned long *flagsp)
+{
+	if (folio_test_lru(folio)) {
+		folio_lruvec_relock_irqsave(folio, lruvecp, flagsp);
+		lruvec_del_folio(*lruvecp, folio);
+		__folio_clear_lru_flags(folio);
+	}
+}
+
+/*
+ * This path almost never happens for VM activity: folios are normally freed
+ * in batches.  But networking and compound folios still occasionally walk in
+ * through this narrow door.
+ */
+static void page_cache_release(struct folio *folio)
+{
+	struct lruvec *lruvec = NULL;
+	unsigned long flags;
+
+	__page_cache_release(folio, &lruvec, &flags);
+	if (lruvec)
+		unlock_page_lruvec_irqrestore(lruvec, flags);
+}
+
+void __folio_put(struct folio *folio)
+{
+	if (unlikely(folio_is_zone_device(folio))) {
+		free_zone_device_folio(folio);
+		return;
+	}
+
+	if (folio_test_hugetlb(folio)) {
+		free_huge_folio(folio);
+		return;
+	}
+
+	page_cache_release(folio);
+	folio_unqueue_deferred_split(folio);
+	mem_cgroup_uncharge(folio);
+	free_frozen_pages(&folio->page, folio_order(folio));
+}
+EXPORT_SYMBOL(__folio_put);
+
+typedef void (*move_fn_t)(struct lruvec *lruvec, struct folio *folio);
+
+static void lru_add(struct lruvec *lruvec, struct folio *folio)
+{
+	int was_unevictable = folio_test_clear_unevictable(folio);
+	long nr_pages = folio_nr_pages(folio);
+
+	VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
+
+	/*
+	 * Is an smp_mb__after_atomic() still required here, before
+	 * folio_evictable() tests the mlocked flag, to rule out the possibility
+	 * of stranding an evictable folio on an unevictable LRU?  I think
+	 * not, because __munlock_folio() only clears the mlocked flag
+	 * while the LRU lock is held.
+	 *
+	 * (That is not true of __page_cache_release(), and not necessarily
+	 * true of folios_put(): but those only clear the mlocked flag after
+	 * folio_put_testzero() has excluded any other users of the folio.)
+	 */
+	if (folio_evictable(folio)) {
+		if (was_unevictable)
+			__count_vm_events(UNEVICTABLE_PGRESCUED, nr_pages);
+	} else {
+		folio_clear_active(folio);
+		folio_set_unevictable(folio);
+		/*
+		 * folio->mlock_count = !!folio_test_mlocked(folio)?
+		 * But that leaves __mlock_folio() in doubt whether another
+		 * actor has already counted the mlock or not.  Err on the
+		 * safe side, underestimate, let page reclaim fix it, rather
+		 * than leaving a page on the unevictable LRU indefinitely.
+		 */
+		folio->mlock_count = 0;
+		if (!was_unevictable)
+			__count_vm_events(UNEVICTABLE_PGCULLED, nr_pages);
+	}
+
+	lruvec_add_folio(lruvec, folio);
+	trace_mm_lru_insertion(folio);
+}
+
+static void folio_batch_move_lru(struct folio_batch *fbatch, move_fn_t move_fn)
+{
+	int i;
+	struct lruvec *lruvec = NULL;
+	unsigned long flags = 0;
+
+	for (i = 0; i < folio_batch_count(fbatch); i++) {
+		struct folio *folio = fbatch->folios[i];
+
+		/* block memcg migration while the folio moves between lru */
+		if (move_fn != lru_add && !folio_test_clear_lru(folio))
+			continue;
+
+		folio_lruvec_relock_irqsave(folio, &lruvec, &flags);
+		move_fn(lruvec, folio);
+
+		folio_set_lru(folio);
+	}
+
+	if (lruvec)
+		unlock_page_lruvec_irqrestore(lruvec, flags);
+	folios_put(fbatch);
+}
+
+static void __folio_batch_add_and_move(struct folio_batch __percpu *fbatch,
+		struct folio *folio, move_fn_t move_fn, bool disable_irq)
+{
+	unsigned long flags;
+
+	folio_get(folio);
+
+	if (disable_irq)
+		local_lock_irqsave(&cpu_fbatches.lock_irq, flags);
+	else
+		local_lock(&cpu_fbatches.lock);
+
+	if (!folio_batch_add(this_cpu_ptr(fbatch), folio) ||
+			!folio_may_be_lru_cached(folio) || lru_cache_disabled())
+		folio_batch_move_lru(this_cpu_ptr(fbatch), move_fn);
+
+	if (disable_irq)
+		local_unlock_irqrestore(&cpu_fbatches.lock_irq, flags);
+	else
+		local_unlock(&cpu_fbatches.lock);
+}
+
+#define folio_batch_add_and_move(folio, op)		\
+	__folio_batch_add_and_move(			\
+		&cpu_fbatches.op,			\
+		folio,					\
+		op,					\
+		offsetof(struct cpu_fbatches, op) >=	\
+		offsetof(struct cpu_fbatches, lock_irq)	\
+	)
+
+static void lru_move_tail(struct lruvec *lruvec, struct folio *folio)
+{
+	if (folio_test_unevictable(folio))
+		return;
+
+	lruvec_del_folio(lruvec, folio);
+	folio_clear_active(folio);
+	lruvec_add_folio_tail(lruvec, folio);
+	__count_vm_events(PGROTATED, folio_nr_pages(folio));
+}
+
+/*
+ * Writeback is about to end against a folio which has been marked for
+ * immediate reclaim.  If it still appears to be reclaimable, move it
+ * to the tail of the inactive list.
+ *
+ * folio_rotate_reclaimable() must disable IRQs, to prevent nasty races.
+ */
+void folio_rotate_reclaimable(struct folio *folio)
+{
+	if (folio_test_locked(folio) || folio_test_dirty(folio) ||
+	    folio_test_unevictable(folio) || !folio_test_lru(folio))
+		return;
+
+	folio_batch_add_and_move(folio, lru_move_tail);
+}
+
+void lru_note_cost_unlock_irq(struct lruvec *lruvec, bool file,
+		unsigned int nr_io, unsigned int nr_rotated) __releases(lruvec->lru_lock)
+{
+	unsigned long cost;
+
+	/*
+	 * Reflect the relative cost of incurring IO and spending CPU
+	 * time on rotations. This doesn't attempt to make a precise
+	 * comparison, it just says: if reloads are about comparable
+	 * between the LRU lists, or rotations are overwhelmingly
+	 * different between them, adjust scan balance for CPU work.
+	 */
+	cost = nr_io * SWAP_CLUSTER_MAX + nr_rotated;
+	if (!cost) {
+		spin_unlock_irq(&lruvec->lru_lock);
+		return;
+	}
+
+	for (;;) {
+		unsigned long lrusize;
+
+		/* Record cost event */
+		if (file)
+			lruvec->file_cost += cost;
+		else
+			lruvec->anon_cost += cost;
+
+		/*
+		 * Decay previous events
+		 *
+		 * Because workloads change over time (and to avoid
+		 * overflow) we keep these statistics as a floating
+		 * average, which ends up weighing recent refaults
+		 * more than old ones.
+		 */
+		lrusize = lruvec_page_state(lruvec, NR_INACTIVE_ANON) +
+			  lruvec_page_state(lruvec, NR_ACTIVE_ANON) +
+			  lruvec_page_state(lruvec, NR_INACTIVE_FILE) +
+			  lruvec_page_state(lruvec, NR_ACTIVE_FILE);
+
+		if (lruvec->file_cost + lruvec->anon_cost > lrusize / 4) {
+			lruvec->file_cost /= 2;
+			lruvec->anon_cost /= 2;
+		}
+
+		spin_unlock_irq(&lruvec->lru_lock);
+		lruvec = parent_lruvec(lruvec);
+		if (!lruvec)
+			break;
+		spin_lock_irq(&lruvec->lru_lock);
+	}
+}
+
+void lru_note_cost_refault(struct folio *folio)
+{
+	struct lruvec *lruvec;
+
+	lruvec = folio_lruvec_lock_irq(folio);
+	lru_note_cost_unlock_irq(lruvec, folio_is_file_lru(folio),
+				folio_nr_pages(folio), 0);
+}
+
+static void lru_activate(struct lruvec *lruvec, struct folio *folio)
+{
+	long nr_pages = folio_nr_pages(folio);
+
+	if (folio_test_active(folio) || folio_test_unevictable(folio))
+		return;
+
+	lruvec_del_folio(lruvec, folio);
+	folio_set_active(folio);
+	lruvec_add_folio(lruvec, folio);
+	trace_mm_lru_activate(folio);
+
+	__count_vm_events(PGACTIVATE, nr_pages);
+	count_memcg_events(lruvec_memcg(lruvec), PGACTIVATE, nr_pages);
+}
+
+#ifdef CONFIG_SMP
+static void folio_activate_drain(int cpu)
+{
+	struct folio_batch *fbatch = &per_cpu(cpu_fbatches.lru_activate, cpu);
+
+	if (folio_batch_count(fbatch))
+		folio_batch_move_lru(fbatch, lru_activate);
+}
+
+void folio_activate(struct folio *folio)
+{
+	if (folio_test_active(folio) || folio_test_unevictable(folio) ||
+	    !folio_test_lru(folio))
+		return;
+
+	folio_batch_add_and_move(folio, lru_activate);
+}
+
+#else
+static inline void folio_activate_drain(int cpu)
+{
+}
+
+void folio_activate(struct folio *folio)
+{
+	struct lruvec *lruvec;
+
+	if (!folio_test_clear_lru(folio))
+		return;
+
+	lruvec = folio_lruvec_lock_irq(folio);
+	lru_activate(lruvec, folio);
+	unlock_page_lruvec_irq(lruvec);
+	folio_set_lru(folio);
+}
+#endif
+
+static void __lru_cache_activate_folio(struct folio *folio)
+{
+	struct folio_batch *fbatch;
+	int i;
+
+	local_lock(&cpu_fbatches.lock);
+	fbatch = this_cpu_ptr(&cpu_fbatches.lru_add);
+
+	/*
+	 * Search backwards on the optimistic assumption that the folio being
+	 * activated has just been added to this batch. Note that only
+	 * the local batch is examined as a !LRU folio could be in the
+	 * process of being released, reclaimed, migrated or on a remote
+	 * batch that is currently being drained. Furthermore, marking
+	 * a remote batch's folio active potentially hits a race where
+	 * a folio is marked active just after it is added to the inactive
+	 * list causing accounting errors and BUG_ON checks to trigger.
+	 */
+	for (i = folio_batch_count(fbatch) - 1; i >= 0; i--) {
+		struct folio *batch_folio = fbatch->folios[i];
+
+		if (batch_folio == folio) {
+			folio_set_active(folio);
+			break;
+		}
+	}
+
+	local_unlock(&cpu_fbatches.lock);
+}
+
+#ifdef CONFIG_LRU_GEN
+
+static void lru_gen_inc_refs(struct folio *folio)
+{
+	unsigned long new_flags, old_flags = READ_ONCE(folio->flags.f);
+
+	if (folio_test_unevictable(folio))
+		return;
+
+	/* see the comment on LRU_REFS_FLAGS */
+	if (!folio_test_referenced(folio)) {
+		set_mask_bits(&folio->flags.f, LRU_REFS_MASK, BIT(PG_referenced));
+		return;
+	}
+
+	do {
+		if ((old_flags & LRU_REFS_MASK) == LRU_REFS_MASK) {
+			if (!folio_test_workingset(folio))
+				folio_set_workingset(folio);
+			return;
+		}
+
+		new_flags = old_flags + BIT(LRU_REFS_PGOFF);
+	} while (!try_cmpxchg(&folio->flags.f, &old_flags, new_flags));
+}
+
+static bool lru_gen_clear_refs(struct folio *folio)
+{
+	struct lru_gen_folio *lrugen;
+	int gen = folio_lru_gen(folio);
+	int type = folio_is_file_lru(folio);
+
+	if (gen < 0)
+		return true;
+
+	set_mask_bits(&folio->flags.f, LRU_REFS_FLAGS | BIT(PG_workingset), 0);
+
+	lrugen = &folio_lruvec(folio)->lrugen;
+	/* whether can do without shuffling under the LRU lock */
+	return gen == lru_gen_from_seq(READ_ONCE(lrugen->min_seq[type]));
+}
+
+#else /* !CONFIG_LRU_GEN */
+
+static void lru_gen_inc_refs(struct folio *folio)
+{
+}
+
+static bool lru_gen_clear_refs(struct folio *folio)
+{
+	return false;
+}
+
+#endif /* CONFIG_LRU_GEN */
+
+/**
+ * folio_mark_accessed - Mark a folio as having seen activity.
+ * @folio: The folio to mark.
+ *
+ * This function will perform one of the following transitions:
+ *
+ * * inactive,unreferenced	->	inactive,referenced
+ * * inactive,referenced	->	active,unreferenced
+ * * active,unreferenced	->	active,referenced
+ *
+ * When a newly allocated folio is not yet visible, so safe for non-atomic ops,
+ * __folio_set_referenced() may be substituted for folio_mark_accessed().
+ */
+void folio_mark_accessed(struct folio *folio)
+{
+	if (folio_test_dropbehind(folio))
+		return;
+	if (lru_gen_enabled()) {
+		lru_gen_inc_refs(folio);
+		return;
+	}
+
+	if (!folio_test_referenced(folio)) {
+		folio_set_referenced(folio);
+	} else if (folio_test_unevictable(folio)) {
+		/*
+		 * Unevictable pages are on the "LRU_UNEVICTABLE" list. But,
+		 * this list is never rotated or maintained, so marking an
+		 * unevictable page accessed has no effect.
+		 */
+	} else if (!folio_test_active(folio)) {
+		/*
+		 * If the folio is on the LRU, queue it for activation via
+		 * cpu_fbatches.lru_activate. Otherwise, assume the folio is in a
+		 * folio_batch, mark it active and it'll be moved to the active
+		 * LRU on the next drain.
+		 */
+		if (folio_test_lru(folio))
+			folio_activate(folio);
+		else
+			__lru_cache_activate_folio(folio);
+		folio_clear_referenced(folio);
+		workingset_activation(folio);
+	}
+	if (folio_test_idle(folio))
+		folio_clear_idle(folio);
+}
+EXPORT_SYMBOL(folio_mark_accessed);
+
+/**
+ * folio_add_lru - Add a folio to an LRU list.
+ * @folio: The folio to be added to the LRU.
+ *
+ * Queue the folio for addition to the LRU. The decision on whether
+ * to add the page to the [in]active [file|anon] list is deferred until the
+ * folio_batch is drained. This gives a chance for the caller of folio_add_lru()
+ * have the folio added to the active list using folio_mark_accessed().
+ */
+void folio_add_lru(struct folio *folio)
+{
+	VM_BUG_ON_FOLIO(folio_test_active(folio) &&
+			folio_test_unevictable(folio), folio);
+	VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
+
+	/* see the comment in lru_gen_folio_seq() */
+	if (lru_gen_enabled() && !folio_test_unevictable(folio) &&
+	    lru_gen_in_fault() && !(current->flags & PF_MEMALLOC))
+		folio_set_active(folio);
+
+	folio_batch_add_and_move(folio, lru_add);
+}
+EXPORT_SYMBOL(folio_add_lru);
+
+/**
+ * folio_add_lru_vma() - Add a folio to the appropriate LRU list for this VMA.
+ * @folio: The folio to be added to the LRU.
+ * @vma: VMA in which the folio is mapped.
+ *
+ * If the VMA is mlocked, @folio is added to the unevictable list.
+ * Otherwise, it is treated the same way as folio_add_lru().
+ */
+void folio_add_lru_vma(struct folio *folio, struct vm_area_struct *vma)
+{
+	VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
+
+	if (unlikely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) == VM_LOCKED))
+		mlock_new_folio(folio);
+	else
+		folio_add_lru(folio);
+}
+
+/*
+ * If the folio cannot be invalidated, it is moved to the
+ * inactive list to speed up its reclaim.  It is moved to the
+ * head of the list, rather than the tail, to give the flusher
+ * threads some time to write it out, as this is much more
+ * effective than the single-page writeout from reclaim.
+ *
+ * If the folio isn't mapped and dirty/writeback, the folio
+ * could be reclaimed asap using the reclaim flag.
+ *
+ * 1. active, mapped folio -> none
+ * 2. active, dirty/writeback folio -> inactive, head, reclaim
+ * 3. inactive, mapped folio -> none
+ * 4. inactive, dirty/writeback folio -> inactive, head, reclaim
+ * 5. inactive, clean -> inactive, tail
+ * 6. Others -> none
+ *
+ * In 4, it moves to the head of the inactive list so the folio is
+ * written out by flusher threads as this is much more efficient
+ * than the single-page writeout from reclaim.
+ */
+static void lru_deactivate_file(struct lruvec *lruvec, struct folio *folio)
+{
+	bool active = folio_test_active(folio) || lru_gen_enabled();
+	long nr_pages = folio_nr_pages(folio);
+
+	if (folio_test_unevictable(folio))
+		return;
+
+	/* Some processes are using the folio */
+	if (folio_mapped(folio))
+		return;
+
+	lruvec_del_folio(lruvec, folio);
+	folio_clear_active(folio);
+	folio_clear_referenced(folio);
+
+	if (folio_test_writeback(folio) || folio_test_dirty(folio)) {
+		/*
+		 * Setting the reclaim flag could race with
+		 * folio_end_writeback() and confuse readahead.  But the
+		 * race window is _really_ small and  it's not a critical
+		 * problem.
+		 */
+		lruvec_add_folio(lruvec, folio);
+		folio_set_reclaim(folio);
+	} else {
+		/*
+		 * The folio's writeback ended while it was in the batch.
+		 * We move that folio to the tail of the inactive list.
+		 */
+		lruvec_add_folio_tail(lruvec, folio);
+		__count_vm_events(PGROTATED, nr_pages);
+	}
+
+	if (active) {
+		__count_vm_events(PGDEACTIVATE, nr_pages);
+		count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE,
+				     nr_pages);
+	}
+}
+
+static void lru_deactivate(struct lruvec *lruvec, struct folio *folio)
+{
+	long nr_pages = folio_nr_pages(folio);
+
+	if (folio_test_unevictable(folio) ||
+	    !(folio_test_active(folio) || lru_gen_enabled()))
+		return;
+
+	lruvec_del_folio(lruvec, folio);
+	folio_clear_active(folio);
+	folio_clear_referenced(folio);
+	lruvec_add_folio(lruvec, folio);
+
+	__count_vm_events(PGDEACTIVATE, nr_pages);
+	count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE, nr_pages);
+}
+
+static void lru_lazyfree(struct lruvec *lruvec, struct folio *folio)
+{
+	long nr_pages = folio_nr_pages(folio);
+
+	if (!folio_test_anon(folio) || !folio_test_swapbacked(folio) ||
+	    folio_test_swapcache(folio) || folio_test_unevictable(folio))
+		return;
+
+	lruvec_del_folio(lruvec, folio);
+	folio_clear_active(folio);
+	if (lru_gen_enabled())
+		lru_gen_clear_refs(folio);
+	else
+		folio_clear_referenced(folio);
+	/*
+	 * Lazyfree folios are clean anonymous folios.  They have
+	 * the swapbacked flag cleared, to distinguish them from normal
+	 * anonymous folios
+	 */
+	folio_clear_swapbacked(folio);
+	lruvec_add_folio(lruvec, folio);
+
+	__count_vm_events(PGLAZYFREE, nr_pages);
+	count_memcg_events(lruvec_memcg(lruvec), PGLAZYFREE, nr_pages);
+}
+
+/*
+ * Drain pages out of the cpu's folio_batch.
+ * Either "cpu" is the current CPU, and preemption has already been
+ * disabled; or "cpu" is being hot-unplugged, and is already dead.
+ */
+void lru_add_drain_cpu(int cpu)
+{
+	struct cpu_fbatches *fbatches = &per_cpu(cpu_fbatches, cpu);
+	struct folio_batch *fbatch = &fbatches->lru_add;
+
+	if (folio_batch_count(fbatch))
+		folio_batch_move_lru(fbatch, lru_add);
+
+	fbatch = &fbatches->lru_move_tail;
+	/* Disabling interrupts below acts as a compiler barrier. */
+	if (data_race(folio_batch_count(fbatch))) {
+		unsigned long flags;
+
+		/* No harm done if a racing interrupt already did this */
+		local_lock_irqsave(&cpu_fbatches.lock_irq, flags);
+		folio_batch_move_lru(fbatch, lru_move_tail);
+		local_unlock_irqrestore(&cpu_fbatches.lock_irq, flags);
+	}
+
+	fbatch = &fbatches->lru_deactivate_file;
+	if (folio_batch_count(fbatch))
+		folio_batch_move_lru(fbatch, lru_deactivate_file);
+
+	fbatch = &fbatches->lru_deactivate;
+	if (folio_batch_count(fbatch))
+		folio_batch_move_lru(fbatch, lru_deactivate);
+
+	fbatch = &fbatches->lru_lazyfree;
+	if (folio_batch_count(fbatch))
+		folio_batch_move_lru(fbatch, lru_lazyfree);
+
+	folio_activate_drain(cpu);
+}
+
+/**
+ * deactivate_file_folio() - Deactivate a file folio.
+ * @folio: Folio to deactivate.
+ *
+ * This function hints to the VM that @folio is a good reclaim candidate,
+ * for example if its invalidation fails due to the folio being dirty
+ * or under writeback.
+ *
+ * Context: Caller holds a reference on the folio.
+ */
+void deactivate_file_folio(struct folio *folio)
+{
+	/* Deactivating an unevictable folio will not accelerate reclaim */
+	if (folio_test_unevictable(folio) || !folio_test_lru(folio))
+		return;
+
+	if (lru_gen_enabled() && lru_gen_clear_refs(folio))
+		return;
+
+	folio_batch_add_and_move(folio, lru_deactivate_file);
+}
+
+/*
+ * folio_deactivate - deactivate a folio
+ * @folio: folio to deactivate
+ *
+ * folio_deactivate() moves @folio to the inactive list if @folio was on the
+ * active list and was not unevictable. This is done to accelerate the
+ * reclaim of @folio.
+ */
+void folio_deactivate(struct folio *folio)
+{
+	if (folio_test_unevictable(folio) || !folio_test_lru(folio))
+		return;
+
+	if (lru_gen_enabled() ? lru_gen_clear_refs(folio) :
+				!folio_test_active(folio))
+		return;
+
+	folio_batch_add_and_move(folio, lru_deactivate);
+}
+
+/**
+ * folio_mark_lazyfree - make an anon folio lazyfree
+ * @folio: folio to deactivate
+ *
+ * folio_mark_lazyfree() moves @folio to the inactive file list.
+ * This is done to accelerate the reclaim of @folio.
+ */
+void folio_mark_lazyfree(struct folio *folio)
+{
+	if (!folio_test_anon(folio) || !folio_test_swapbacked(folio) ||
+	    !folio_test_lru(folio) ||
+	    folio_test_swapcache(folio) || folio_test_unevictable(folio))
+		return;
+
+	folio_batch_add_and_move(folio, lru_lazyfree);
+}
+
+void lru_add_drain(void)
+{
+	local_lock(&cpu_fbatches.lock);
+	lru_add_drain_cpu(smp_processor_id());
+	local_unlock(&cpu_fbatches.lock);
+	mlock_drain_local();
+}
+
+/*
+ * It's called from per-cpu workqueue context in SMP case so
+ * lru_add_drain_cpu and invalidate_bh_lrus_cpu should run on
+ * the same cpu. It shouldn't be a problem in !SMP case since
+ * the core is only one and the locks will disable preemption.
+ */
+static void lru_add_and_bh_lrus_drain(void)
+{
+	local_lock(&cpu_fbatches.lock);
+	lru_add_drain_cpu(smp_processor_id());
+	local_unlock(&cpu_fbatches.lock);
+	invalidate_bh_lrus_cpu();
+	mlock_drain_local();
+}
+
+void lru_add_drain_cpu_zone(struct zone *zone)
+{
+	local_lock(&cpu_fbatches.lock);
+	lru_add_drain_cpu(smp_processor_id());
+	drain_local_pages(zone);
+	local_unlock(&cpu_fbatches.lock);
+	mlock_drain_local();
+}
+
+#ifdef CONFIG_SMP
+
+static DEFINE_PER_CPU(struct work_struct, lru_add_drain_work);
+
+static void lru_add_drain_per_cpu(struct work_struct *dummy)
+{
+	lru_add_and_bh_lrus_drain();
+}
+
+static bool cpu_needs_drain(unsigned int cpu)
+{
+	struct cpu_fbatches *fbatches = &per_cpu(cpu_fbatches, cpu);
+
+	/* Check these in order of likelihood that they're not zero */
+	return folio_batch_count(&fbatches->lru_add) ||
+		folio_batch_count(&fbatches->lru_move_tail) ||
+		folio_batch_count(&fbatches->lru_deactivate_file) ||
+		folio_batch_count(&fbatches->lru_deactivate) ||
+		folio_batch_count(&fbatches->lru_lazyfree) ||
+		folio_batch_count(&fbatches->lru_activate) ||
+		need_mlock_drain(cpu) ||
+		has_bh_in_lru(cpu, NULL);
+}
+
+/*
+ * Doesn't need any cpu hotplug locking because we do rely on per-cpu
+ * kworkers being shut down before our page_alloc_cpu_dead callback is
+ * executed on the offlined cpu.
+ * Calling this function with cpu hotplug locks held can actually lead
+ * to obscure indirect dependencies via WQ context.
+ */
+static inline void __lru_add_drain_all(bool force_all_cpus)
+{
+	/*
+	 * lru_drain_gen - Global pages generation number
+	 *
+	 * (A) Definition: global lru_drain_gen = x implies that all generations
+	 *     0 < n <= x are already *scheduled* for draining.
+	 *
+	 * This is an optimization for the highly-contended use case where a
+	 * user space workload keeps constantly generating a flow of pages for
+	 * each CPU.
+	 */
+	static unsigned int lru_drain_gen;
+	static struct cpumask has_work;
+	static DEFINE_MUTEX(lock);
+	unsigned int cpu, this_gen;
+
+	/*
+	 * Make sure nobody triggers this path before mm_percpu_wq is fully
+	 * initialized.
+	 */
+	if (WARN_ON(!mm_percpu_wq))
+		return;
+
+	/*
+	 * Guarantee folio_batch counter stores visible by this CPU
+	 * are visible to other CPUs before loading the current drain
+	 * generation.
+	 */
+	smp_mb();
+
+	/*
+	 * (B) Locally cache global LRU draining generation number
+	 *
+	 * The read barrier ensures that the counter is loaded before the mutex
+	 * is taken. It pairs with smp_mb() inside the mutex critical section
+	 * at (D).
+	 */
+	this_gen = smp_load_acquire(&lru_drain_gen);
+
+	/* It helps everyone if we do our own local drain immediately. */
+	lru_add_drain();
+
+	mutex_lock(&lock);
+
+	/*
+	 * (C) Exit the draining operation if a newer generation, from another
+	 * lru_add_drain_all(), was already scheduled for draining. Check (A).
+	 */
+	if (unlikely(this_gen != lru_drain_gen && !force_all_cpus))
+		goto done;
+
+	/*
+	 * (D) Increment global generation number
+	 *
+	 * Pairs with smp_load_acquire() at (B), outside of the critical
+	 * section. Use a full memory barrier to guarantee that the
+	 * new global drain generation number is stored before loading
+	 * folio_batch counters.
+	 *
+	 * This pairing must be done here, before the for_each_online_cpu loop
+	 * below which drains the page vectors.
+	 *
+	 * Let x, y, and z represent some system CPU numbers, where x < y < z.
+	 * Assume CPU #z is in the middle of the for_each_online_cpu loop
+	 * below and has already reached CPU #y's per-cpu data. CPU #x comes
+	 * along, adds some pages to its per-cpu vectors, then calls
+	 * lru_add_drain_all().
+	 *
+	 * If the paired barrier is done at any later step, e.g. after the
+	 * loop, CPU #x will just exit at (C) and miss flushing out all of its
+	 * added pages.
+	 */
+	WRITE_ONCE(lru_drain_gen, lru_drain_gen + 1);
+	/* Publish the new generation before sampling per-cpu folio batches. */
+	smp_mb();
+
+	cpumask_clear(&has_work);
+	for_each_online_cpu(cpu) {
+		struct work_struct *work = &per_cpu(lru_add_drain_work, cpu);
+
+		if (cpu_needs_drain(cpu)) {
+			INIT_WORK(work, lru_add_drain_per_cpu);
+			queue_work_on(cpu, mm_percpu_wq, work);
+			__cpumask_set_cpu(cpu, &has_work);
+		}
+	}
+
+	for_each_cpu(cpu, &has_work)
+		flush_work(&per_cpu(lru_add_drain_work, cpu));
+
+done:
+	mutex_unlock(&lock);
+}
+
+void lru_add_drain_all(void)
+{
+	__lru_add_drain_all(false);
+}
+#else
+void lru_add_drain_all(void)
+{
+	lru_add_drain();
+}
+#endif /* CONFIG_SMP */
+
+atomic_t lru_disable_count = ATOMIC_INIT(0);
+
+/*
+ * lru_cache_disable() needs to be called before we start compiling
+ * a list of folios to be migrated using folio_isolate_lru().
+ * It drains folios on LRU cache and then disable on all cpus until
+ * lru_cache_enable is called.
+ *
+ * Must be paired with a call to lru_cache_enable().
+ */
+void lru_cache_disable(void)
+{
+	atomic_inc(&lru_disable_count);
+	/*
+	 * Readers of lru_disable_count are protected by either disabling
+	 * preemption or rcu_read_lock:
+	 *
+	 * preempt_disable, local_irq_disable  [bh_lru_lock()]
+	 * rcu_read_lock		       [rt_spin_lock CONFIG_PREEMPT_RT]
+	 * preempt_disable		       [local_lock !CONFIG_PREEMPT_RT]
+	 *
+	 * Since v5.1 kernel, synchronize_rcu() is guaranteed to wait on
+	 * preempt_disable() regions of code. So any CPU which sees
+	 * lru_disable_count = 0 will have exited the critical
+	 * section when synchronize_rcu() returns.
+	 */
+	synchronize_rcu_expedited();
+#ifdef CONFIG_SMP
+	__lru_add_drain_all(true);
+#else
+	lru_add_and_bh_lrus_drain();
+#endif
+}
+
+/**
+ * folios_put_refs - Reduce the reference count on a batch of folios.
+ * @folios: The folios.
+ * @refs: The number of refs to subtract from each folio.
+ *
+ * Like folio_put(), but for a batch of folios.  This is more efficient
+ * than writing the loop yourself as it will optimise the locks which need
+ * to be taken if the folios are freed.  The folios batch is returned
+ * empty and ready to be reused for another batch; there is no need
+ * to reinitialise it.  If @refs is NULL, we subtract one from each
+ * folio refcount.
+ *
+ * Context: May be called in process or interrupt context, but not in NMI
+ * context.  May be called while holding a spinlock.
+ */
+void folios_put_refs(struct folio_batch *folios, unsigned int *refs)
+{
+	int i, j;
+	struct lruvec *lruvec = NULL;
+	unsigned long flags = 0;
+
+	for (i = 0, j = 0; i < folios->nr; i++) {
+		struct folio *folio = folios->folios[i];
+		unsigned int nr_refs = refs ? refs[i] : 1;
+
+		if (is_huge_zero_folio(folio))
+			continue;
+
+		if (folio_is_zone_device(folio)) {
+			if (lruvec) {
+				unlock_page_lruvec_irqrestore(lruvec, flags);
+				lruvec = NULL;
+			}
+			if (folio_ref_sub_and_test(folio, nr_refs))
+				free_zone_device_folio(folio);
+			continue;
+		}
+
+		if (!folio_ref_sub_and_test(folio, nr_refs))
+			continue;
+
+		/* hugetlb has its own memcg */
+		if (folio_test_hugetlb(folio)) {
+			if (lruvec) {
+				unlock_page_lruvec_irqrestore(lruvec, flags);
+				lruvec = NULL;
+			}
+			free_huge_folio(folio);
+			continue;
+		}
+		folio_unqueue_deferred_split(folio);
+		__page_cache_release(folio, &lruvec, &flags);
+
+		if (j != i)
+			folios->folios[j] = folio;
+		j++;
+	}
+	if (lruvec)
+		unlock_page_lruvec_irqrestore(lruvec, flags);
+	if (!j) {
+		folio_batch_reinit(folios);
+		return;
+	}
+
+	folios->nr = j;
+	mem_cgroup_uncharge_folios(folios);
+	free_unref_folios(folios);
+}
+EXPORT_SYMBOL(folios_put_refs);
+
+/**
+ * release_pages - batched put_page()
+ * @arg: array of pages to release
+ * @nr: number of pages
+ *
+ * Decrement the reference count on all the pages in @arg.  If it
+ * fell to zero, remove the page from the LRU and free it.
+ *
+ * Note that the argument can be an array of pages, encoded pages,
+ * or folio pointers. We ignore any encoded bits, and turn any of
+ * them into just a folio that gets free'd.
+ */
+void release_pages(release_pages_arg arg, int nr)
+{
+	struct folio_batch fbatch;
+	int refs[PAGEVEC_SIZE];
+	struct encoded_page **encoded = arg.encoded_pages;
+	int i;
+
+	folio_batch_init(&fbatch);
+	for (i = 0; i < nr; i++) {
+		/* Turn any of the argument types into a folio */
+		struct folio *folio = page_folio(encoded_page_ptr(encoded[i]));
+
+		/* Is our next entry actually "nr_pages" -> "nr_refs" ? */
+		refs[fbatch.nr] = 1;
+		if (unlikely(encoded_page_flags(encoded[i]) &
+			     ENCODED_PAGE_BIT_NR_PAGES_NEXT))
+			refs[fbatch.nr] = encoded_nr_pages(encoded[++i]);
+
+		if (folio_batch_add(&fbatch, folio) > 0)
+			continue;
+		folios_put_refs(&fbatch, refs);
+	}
+
+	if (fbatch.nr)
+		folios_put_refs(&fbatch, refs);
+}
+EXPORT_SYMBOL(release_pages);
+
+/*
+ * The folios which we're about to release may be in the deferred lru-addition
+ * queues.  That would prevent them from really being freed right now.  That's
+ * OK from a correctness point of view but is inefficient - those folios may be
+ * cache-warm and we want to give them back to the page allocator ASAP.
+ *
+ * So __folio_batch_release() will drain those queues here.
+ * folio_batch_move_lru() calls folios_put() directly to avoid
+ * mutual recursion.
+ */
+void __folio_batch_release(struct folio_batch *fbatch)
+{
+	if (!fbatch->percpu_pvec_drained) {
+		lru_add_drain();
+		fbatch->percpu_pvec_drained = true;
+	}
+	folios_put(fbatch);
+}
+EXPORT_SYMBOL(__folio_batch_release);
+
+/**
+ * folio_batch_remove_exceptionals() - Prune non-folios from a batch.
+ * @fbatch: The batch to prune
+ *
+ * find_get_entries() fills a batch with both folios and shadow/swap/DAX
+ * entries.  This function prunes all the non-folio entries from @fbatch
+ * without leaving holes, so that it can be passed on to folio-only batch
+ * operations.
+ */
+void folio_batch_remove_exceptionals(struct folio_batch *fbatch)
+{
+	unsigned int i, j;
+
+	for (i = 0, j = 0; i < folio_batch_count(fbatch); i++) {
+		struct folio *folio = fbatch->folios[i];
+
+		if (!xa_is_value(folio))
+			fbatch->folios[j++] = folio;
+	}
+	fbatch->nr = j;
+}
diff --git a/mm/folio_lru.h b/mm/folio_lru.h
new file mode 100644
index 000000000000..06f4779796f1
--- /dev/null
+++ b/mm/folio_lru.h
@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _MM_FOLIO_LRU_H
+#define _MM_FOLIO_LRU_H
+
+/*
+ * Declarations for mm/folio_lru.c.
+ */
+
+#include <linux/atomic.h>
+#include <linux/mmzone.h>
+#include <linux/page-flags.h>
+
+struct folio;
+
+void lru_note_cost_unlock_irq(struct lruvec *lruvec, bool file,
+		unsigned int nr_io, unsigned int nr_rotated) __releases(lruvec->lru_lock);
+void lru_note_cost_refault(struct folio *folio);
+void folio_add_lru(struct folio *folio);
+void folio_add_lru_vma(struct folio *folio, struct vm_area_struct *vma);
+void mark_page_accessed(struct page *page);
+void folio_mark_accessed(struct folio *folio);
+
+extern atomic_t lru_disable_count;
+
+static inline bool lru_cache_disabled(void)
+{
+	return atomic_read(&lru_disable_count);
+}
+
+static inline void lru_cache_enable(void)
+{
+	atomic_dec(&lru_disable_count);
+}
+
+void lru_cache_disable(void);
+void lru_add_drain(void);
+void lru_add_drain_cpu(int cpu);
+void lru_add_drain_cpu_zone(struct zone *zone);
+void lru_add_drain_all(void);
+void folio_deactivate(struct folio *folio);
+void folio_mark_lazyfree(struct folio *folio);
+
+static inline bool folio_may_be_lru_cached(struct folio *folio)
+{
+	/*
+	 * Holding PMD-sized folios in per-CPU LRU cache unbalances accounting.
+	 * Holding small numbers of low-order mTHP folios in per-CPU LRU cache
+	 * will be sensible, but nobody has implemented and tested that yet.
+	 */
+	return !folio_test_large(folio);
+}
+
+#endif /* _MM_FOLIO_LRU_H */
diff --git a/mm/swap.c b/mm/swap.c
index bb19ccbece46..d89098db2c81 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -15,1075 +15,13 @@
  */

 #include <linux/mm.h>
-#include <linux/sched.h>
-#include <linux/kernel_stat.h>
-#include <linux/swap.h>
-#include <linux/mman.h>
-#include <linux/pagemap.h>
-#include <linux/pagevec.h>
 #include <linux/init.h>
-#include <linux/export.h>
-#include <linux/mm_inline.h>
-#include <linux/percpu_counter.h>
-#include <linux/memremap.h>
-#include <linux/percpu.h>
-#include <linux/cpu.h>
-#include <linux/notifier.h>
-#include <linux/backing-dev.h>
-#include <linux/memcontrol.h>
-#include <linux/gfp.h>
-#include <linux/uio.h>
-#include <linux/hugetlb.h>
-#include <linux/page_idle.h>
-#include <linux/local_lock.h>
-#include <linux/buffer_head.h>
-
-#include "internal.h"
-
-#define CREATE_TRACE_POINTS
-#include <trace/events/pagemap.h>
+#include <linux/swap.h>

 /* How many pages do we try to swap or page in/out together? As a power of 2 */
 int page_cluster;
 static const int page_cluster_max = 31;

-struct cpu_fbatches {
-	/*
-	 * The following folio batches are grouped together because they are protected
-	 * by disabling preemption (and interrupts remain enabled).
-	 */
-	local_lock_t lock;
-	struct folio_batch lru_add;
-	struct folio_batch lru_deactivate_file;
-	struct folio_batch lru_deactivate;
-	struct folio_batch lru_lazyfree;
-#ifdef CONFIG_SMP
-	struct folio_batch lru_activate;
-#endif
-	/* Protecting the following batches which require disabling interrupts */
-	local_lock_t lock_irq;
-	struct folio_batch lru_move_tail;
-};
-
-static DEFINE_PER_CPU(struct cpu_fbatches, cpu_fbatches) = {
-	.lock = INIT_LOCAL_LOCK(lock),
-	.lock_irq = INIT_LOCAL_LOCK(lock_irq),
-};
-
-static void __page_cache_release(struct folio *folio, struct lruvec **lruvecp,
-		unsigned long *flagsp)
-{
-	if (folio_test_lru(folio)) {
-		folio_lruvec_relock_irqsave(folio, lruvecp, flagsp);
-		lruvec_del_folio(*lruvecp, folio);
-		__folio_clear_lru_flags(folio);
-	}
-}
-
-/*
- * This path almost never happens for VM activity - pages are normally freed
- * in batches.  But it gets used by networking - and for compound pages.
- */
-static void page_cache_release(struct folio *folio)
-{
-	struct lruvec *lruvec = NULL;
-	unsigned long flags;
-
-	__page_cache_release(folio, &lruvec, &flags);
-	if (lruvec)
-		unlock_page_lruvec_irqrestore(lruvec, flags);
-}
-
-void __folio_put(struct folio *folio)
-{
-	if (unlikely(folio_is_zone_device(folio))) {
-		free_zone_device_folio(folio);
-		return;
-	}
-
-	if (folio_test_hugetlb(folio)) {
-		free_huge_folio(folio);
-		return;
-	}
-
-	page_cache_release(folio);
-	folio_unqueue_deferred_split(folio);
-	mem_cgroup_uncharge(folio);
-	free_frozen_pages(&folio->page, folio_order(folio));
-}
-EXPORT_SYMBOL(__folio_put);
-
-typedef void (*move_fn_t)(struct lruvec *lruvec, struct folio *folio);
-
-static void lru_add(struct lruvec *lruvec, struct folio *folio)
-{
-	int was_unevictable = folio_test_clear_unevictable(folio);
-	long nr_pages = folio_nr_pages(folio);
-
-	VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
-
-	/*
-	 * Is an smp_mb__after_atomic() still required here, before
-	 * folio_evictable() tests the mlocked flag, to rule out the possibility
-	 * of stranding an evictable folio on an unevictable LRU?  I think
-	 * not, because __munlock_folio() only clears the mlocked flag
-	 * while the LRU lock is held.
-	 *
-	 * (That is not true of __page_cache_release(), and not necessarily
-	 * true of folios_put(): but those only clear the mlocked flag after
-	 * folio_put_testzero() has excluded any other users of the folio.)
-	 */
-	if (folio_evictable(folio)) {
-		if (was_unevictable)
-			__count_vm_events(UNEVICTABLE_PGRESCUED, nr_pages);
-	} else {
-		folio_clear_active(folio);
-		folio_set_unevictable(folio);
-		/*
-		 * folio->mlock_count = !!folio_test_mlocked(folio)?
-		 * But that leaves __mlock_folio() in doubt whether another
-		 * actor has already counted the mlock or not.  Err on the
-		 * safe side, underestimate, let page reclaim fix it, rather
-		 * than leaving a page on the unevictable LRU indefinitely.
-		 */
-		folio->mlock_count = 0;
-		if (!was_unevictable)
-			__count_vm_events(UNEVICTABLE_PGCULLED, nr_pages);
-	}
-
-	lruvec_add_folio(lruvec, folio);
-	trace_mm_lru_insertion(folio);
-}
-
-static void folio_batch_move_lru(struct folio_batch *fbatch, move_fn_t move_fn)
-{
-	int i;
-	struct lruvec *lruvec = NULL;
-	unsigned long flags = 0;
-
-	for (i = 0; i < folio_batch_count(fbatch); i++) {
-		struct folio *folio = fbatch->folios[i];
-
-		/* block memcg migration while the folio moves between lru */
-		if (move_fn != lru_add && !folio_test_clear_lru(folio))
-			continue;
-
-		folio_lruvec_relock_irqsave(folio, &lruvec, &flags);
-		move_fn(lruvec, folio);
-
-		folio_set_lru(folio);
-	}
-
-	if (lruvec)
-		unlock_page_lruvec_irqrestore(lruvec, flags);
-	folios_put(fbatch);
-}
-
-static void __folio_batch_add_and_move(struct folio_batch __percpu *fbatch,
-		struct folio *folio, move_fn_t move_fn, bool disable_irq)
-{
-	unsigned long flags;
-
-	folio_get(folio);
-
-	if (disable_irq)
-		local_lock_irqsave(&cpu_fbatches.lock_irq, flags);
-	else
-		local_lock(&cpu_fbatches.lock);
-
-	if (!folio_batch_add(this_cpu_ptr(fbatch), folio) ||
-			!folio_may_be_lru_cached(folio) || lru_cache_disabled())
-		folio_batch_move_lru(this_cpu_ptr(fbatch), move_fn);
-
-	if (disable_irq)
-		local_unlock_irqrestore(&cpu_fbatches.lock_irq, flags);
-	else
-		local_unlock(&cpu_fbatches.lock);
-}
-
-#define folio_batch_add_and_move(folio, op)		\
-	__folio_batch_add_and_move(			\
-		&cpu_fbatches.op,			\
-		folio,					\
-		op,					\
-		offsetof(struct cpu_fbatches, op) >=	\
-		offsetof(struct cpu_fbatches, lock_irq)	\
-	)
-
-static void lru_move_tail(struct lruvec *lruvec, struct folio *folio)
-{
-	if (folio_test_unevictable(folio))
-		return;
-
-	lruvec_del_folio(lruvec, folio);
-	folio_clear_active(folio);
-	lruvec_add_folio_tail(lruvec, folio);
-	__count_vm_events(PGROTATED, folio_nr_pages(folio));
-}
-
-/*
- * Writeback is about to end against a folio which has been marked for
- * immediate reclaim.  If it still appears to be reclaimable, move it
- * to the tail of the inactive list.
- *
- * folio_rotate_reclaimable() must disable IRQs, to prevent nasty races.
- */
-void folio_rotate_reclaimable(struct folio *folio)
-{
-	if (folio_test_locked(folio) || folio_test_dirty(folio) ||
-	    folio_test_unevictable(folio) || !folio_test_lru(folio))
-		return;
-
-	folio_batch_add_and_move(folio, lru_move_tail);
-}
-
-void lru_note_cost_unlock_irq(struct lruvec *lruvec, bool file,
-		unsigned int nr_io, unsigned int nr_rotated)
-		__releases(lruvec->lru_lock)
-{
-	unsigned long cost;
-
-	/*
-	 * Reflect the relative cost of incurring IO and spending CPU
-	 * time on rotations. This doesn't attempt to make a precise
-	 * comparison, it just says: if reloads are about comparable
-	 * between the LRU lists, or rotations are overwhelmingly
-	 * different between them, adjust scan balance for CPU work.
-	 */
-	cost = nr_io * SWAP_CLUSTER_MAX + nr_rotated;
-	if (!cost) {
-		spin_unlock_irq(&lruvec->lru_lock);
-		return;
-	}
-
-	for (;;) {
-		unsigned long lrusize;
-
-		/* Record cost event */
-		if (file)
-			lruvec->file_cost += cost;
-		else
-			lruvec->anon_cost += cost;
-
-		/*
-		 * Decay previous events
-		 *
-		 * Because workloads change over time (and to avoid
-		 * overflow) we keep these statistics as a floating
-		 * average, which ends up weighing recent refaults
-		 * more than old ones.
-		 */
-		lrusize = lruvec_page_state(lruvec, NR_INACTIVE_ANON) +
-			  lruvec_page_state(lruvec, NR_ACTIVE_ANON) +
-			  lruvec_page_state(lruvec, NR_INACTIVE_FILE) +
-			  lruvec_page_state(lruvec, NR_ACTIVE_FILE);
-
-		if (lruvec->file_cost + lruvec->anon_cost > lrusize / 4) {
-			lruvec->file_cost /= 2;
-			lruvec->anon_cost /= 2;
-		}
-
-		spin_unlock_irq(&lruvec->lru_lock);
-		lruvec = parent_lruvec(lruvec);
-		if (!lruvec)
-			break;
-		spin_lock_irq(&lruvec->lru_lock);
-	}
-}
-
-void lru_note_cost_refault(struct folio *folio)
-{
-	struct lruvec *lruvec;
-
-	lruvec = folio_lruvec_lock_irq(folio);
-	lru_note_cost_unlock_irq(lruvec, folio_is_file_lru(folio),
-				folio_nr_pages(folio), 0);
-}
-
-static void lru_activate(struct lruvec *lruvec, struct folio *folio)
-{
-	long nr_pages = folio_nr_pages(folio);
-
-	if (folio_test_active(folio) || folio_test_unevictable(folio))
-		return;
-
-
-	lruvec_del_folio(lruvec, folio);
-	folio_set_active(folio);
-	lruvec_add_folio(lruvec, folio);
-	trace_mm_lru_activate(folio);
-
-	__count_vm_events(PGACTIVATE, nr_pages);
-	count_memcg_events(lruvec_memcg(lruvec), PGACTIVATE, nr_pages);
-}
-
-#ifdef CONFIG_SMP
-static void folio_activate_drain(int cpu)
-{
-	struct folio_batch *fbatch = &per_cpu(cpu_fbatches.lru_activate, cpu);
-
-	if (folio_batch_count(fbatch))
-		folio_batch_move_lru(fbatch, lru_activate);
-}
-
-void folio_activate(struct folio *folio)
-{
-	if (folio_test_active(folio) || folio_test_unevictable(folio) ||
-	    !folio_test_lru(folio))
-		return;
-
-	folio_batch_add_and_move(folio, lru_activate);
-}
-
-#else
-static inline void folio_activate_drain(int cpu)
-{
-}
-
-void folio_activate(struct folio *folio)
-{
-	struct lruvec *lruvec;
-
-	if (!folio_test_clear_lru(folio))
-		return;
-
-	lruvec = folio_lruvec_lock_irq(folio);
-	lru_activate(lruvec, folio);
-	unlock_page_lruvec_irq(lruvec);
-	folio_set_lru(folio);
-}
-#endif
-
-static void __lru_cache_activate_folio(struct folio *folio)
-{
-	struct folio_batch *fbatch;
-	int i;
-
-	local_lock(&cpu_fbatches.lock);
-	fbatch = this_cpu_ptr(&cpu_fbatches.lru_add);
-
-	/*
-	 * Search backwards on the optimistic assumption that the folio being
-	 * activated has just been added to this batch. Note that only
-	 * the local batch is examined as a !LRU folio could be in the
-	 * process of being released, reclaimed, migrated or on a remote
-	 * batch that is currently being drained. Furthermore, marking
-	 * a remote batch's folio active potentially hits a race where
-	 * a folio is marked active just after it is added to the inactive
-	 * list causing accounting errors and BUG_ON checks to trigger.
-	 */
-	for (i = folio_batch_count(fbatch) - 1; i >= 0; i--) {
-		struct folio *batch_folio = fbatch->folios[i];
-
-		if (batch_folio == folio) {
-			folio_set_active(folio);
-			break;
-		}
-	}
-
-	local_unlock(&cpu_fbatches.lock);
-}
-
-#ifdef CONFIG_LRU_GEN
-
-static void lru_gen_inc_refs(struct folio *folio)
-{
-	unsigned long new_flags, old_flags = READ_ONCE(folio->flags.f);
-
-	if (folio_test_unevictable(folio))
-		return;
-
-	/* see the comment on LRU_REFS_FLAGS */
-	if (!folio_test_referenced(folio)) {
-		set_mask_bits(&folio->flags.f, LRU_REFS_MASK, BIT(PG_referenced));
-		return;
-	}
-
-	do {
-		if ((old_flags & LRU_REFS_MASK) == LRU_REFS_MASK) {
-			if (!folio_test_workingset(folio))
-				folio_set_workingset(folio);
-			return;
-		}
-
-		new_flags = old_flags + BIT(LRU_REFS_PGOFF);
-	} while (!try_cmpxchg(&folio->flags.f, &old_flags, new_flags));
-}
-
-static bool lru_gen_clear_refs(struct folio *folio)
-{
-	struct lru_gen_folio *lrugen;
-	int gen = folio_lru_gen(folio);
-	int type = folio_is_file_lru(folio);
-
-	if (gen < 0)
-		return true;
-
-	set_mask_bits(&folio->flags.f, LRU_REFS_FLAGS | BIT(PG_workingset), 0);
-
-	lrugen = &folio_lruvec(folio)->lrugen;
-	/* whether can do without shuffling under the LRU lock */
-	return gen == lru_gen_from_seq(READ_ONCE(lrugen->min_seq[type]));
-}
-
-#else /* !CONFIG_LRU_GEN */
-
-static void lru_gen_inc_refs(struct folio *folio)
-{
-}
-
-static bool lru_gen_clear_refs(struct folio *folio)
-{
-	return false;
-}
-
-#endif /* CONFIG_LRU_GEN */
-
-/**
- * folio_mark_accessed - Mark a folio as having seen activity.
- * @folio: The folio to mark.
- *
- * This function will perform one of the following transitions:
- *
- * * inactive,unreferenced	->	inactive,referenced
- * * inactive,referenced	->	active,unreferenced
- * * active,unreferenced	->	active,referenced
- *
- * When a newly allocated folio is not yet visible, so safe for non-atomic ops,
- * __folio_set_referenced() may be substituted for folio_mark_accessed().
- */
-void folio_mark_accessed(struct folio *folio)
-{
-	if (folio_test_dropbehind(folio))
-		return;
-	if (lru_gen_enabled()) {
-		lru_gen_inc_refs(folio);
-		return;
-	}
-
-	if (!folio_test_referenced(folio)) {
-		folio_set_referenced(folio);
-	} else if (folio_test_unevictable(folio)) {
-		/*
-		 * Unevictable pages are on the "LRU_UNEVICTABLE" list. But,
-		 * this list is never rotated or maintained, so marking an
-		 * unevictable page accessed has no effect.
-		 */
-	} else if (!folio_test_active(folio)) {
-		/*
-		 * If the folio is on the LRU, queue it for activation via
-		 * cpu_fbatches.lru_activate. Otherwise, assume the folio is in a
-		 * folio_batch, mark it active and it'll be moved to the active
-		 * LRU on the next drain.
-		 */
-		if (folio_test_lru(folio))
-			folio_activate(folio);
-		else
-			__lru_cache_activate_folio(folio);
-		folio_clear_referenced(folio);
-		workingset_activation(folio);
-	}
-	if (folio_test_idle(folio))
-		folio_clear_idle(folio);
-}
-EXPORT_SYMBOL(folio_mark_accessed);
-
-/**
- * folio_add_lru - Add a folio to an LRU list.
- * @folio: The folio to be added to the LRU.
- *
- * Queue the folio for addition to the LRU. The decision on whether
- * to add the page to the [in]active [file|anon] list is deferred until the
- * folio_batch is drained. This gives a chance for the caller of folio_add_lru()
- * have the folio added to the active list using folio_mark_accessed().
- */
-void folio_add_lru(struct folio *folio)
-{
-	VM_BUG_ON_FOLIO(folio_test_active(folio) &&
-			folio_test_unevictable(folio), folio);
-	VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
-
-	/* see the comment in lru_gen_folio_seq() */
-	if (lru_gen_enabled() && !folio_test_unevictable(folio) &&
-	    lru_gen_in_fault() && !(current->flags & PF_MEMALLOC))
-		folio_set_active(folio);
-
-	folio_batch_add_and_move(folio, lru_add);
-}
-EXPORT_SYMBOL(folio_add_lru);
-
-/**
- * folio_add_lru_vma() - Add a folio to the appropriate LRU list for this VMA.
- * @folio: The folio to be added to the LRU.
- * @vma: VMA in which the folio is mapped.
- *
- * If the VMA is mlocked, @folio is added to the unevictable list.
- * Otherwise, it is treated the same way as folio_add_lru().
- */
-void folio_add_lru_vma(struct folio *folio, struct vm_area_struct *vma)
-{
-	VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
-
-	if (unlikely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) == VM_LOCKED))
-		mlock_new_folio(folio);
-	else
-		folio_add_lru(folio);
-}
-
-/*
- * If the folio cannot be invalidated, it is moved to the
- * inactive list to speed up its reclaim.  It is moved to the
- * head of the list, rather than the tail, to give the flusher
- * threads some time to write it out, as this is much more
- * effective than the single-page writeout from reclaim.
- *
- * If the folio isn't mapped and dirty/writeback, the folio
- * could be reclaimed asap using the reclaim flag.
- *
- * 1. active, mapped folio -> none
- * 2. active, dirty/writeback folio -> inactive, head, reclaim
- * 3. inactive, mapped folio -> none
- * 4. inactive, dirty/writeback folio -> inactive, head, reclaim
- * 5. inactive, clean -> inactive, tail
- * 6. Others -> none
- *
- * In 4, it moves to the head of the inactive list so the folio is
- * written out by flusher threads as this is much more efficient
- * than the single-page writeout from reclaim.
- */
-static void lru_deactivate_file(struct lruvec *lruvec, struct folio *folio)
-{
-	bool active = folio_test_active(folio) || lru_gen_enabled();
-	long nr_pages = folio_nr_pages(folio);
-
-	if (folio_test_unevictable(folio))
-		return;
-
-	/* Some processes are using the folio */
-	if (folio_mapped(folio))
-		return;
-
-	lruvec_del_folio(lruvec, folio);
-	folio_clear_active(folio);
-	folio_clear_referenced(folio);
-
-	if (folio_test_writeback(folio) || folio_test_dirty(folio)) {
-		/*
-		 * Setting the reclaim flag could race with
-		 * folio_end_writeback() and confuse readahead.  But the
-		 * race window is _really_ small and  it's not a critical
-		 * problem.
-		 */
-		lruvec_add_folio(lruvec, folio);
-		folio_set_reclaim(folio);
-	} else {
-		/*
-		 * The folio's writeback ended while it was in the batch.
-		 * We move that folio to the tail of the inactive list.
-		 */
-		lruvec_add_folio_tail(lruvec, folio);
-		__count_vm_events(PGROTATED, nr_pages);
-	}
-
-	if (active) {
-		__count_vm_events(PGDEACTIVATE, nr_pages);
-		count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE,
-				     nr_pages);
-	}
-}
-
-static void lru_deactivate(struct lruvec *lruvec, struct folio *folio)
-{
-	long nr_pages = folio_nr_pages(folio);
-
-	if (folio_test_unevictable(folio) || !(folio_test_active(folio) || lru_gen_enabled()))
-		return;
-
-	lruvec_del_folio(lruvec, folio);
-	folio_clear_active(folio);
-	folio_clear_referenced(folio);
-	lruvec_add_folio(lruvec, folio);
-
-	__count_vm_events(PGDEACTIVATE, nr_pages);
-	count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE, nr_pages);
-}
-
-static void lru_lazyfree(struct lruvec *lruvec, struct folio *folio)
-{
-	long nr_pages = folio_nr_pages(folio);
-
-	if (!folio_test_anon(folio) || !folio_test_swapbacked(folio) ||
-	    folio_test_swapcache(folio) || folio_test_unevictable(folio))
-		return;
-
-	lruvec_del_folio(lruvec, folio);
-	folio_clear_active(folio);
-	if (lru_gen_enabled())
-		lru_gen_clear_refs(folio);
-	else
-		folio_clear_referenced(folio);
-	/*
-	 * Lazyfree folios are clean anonymous folios.  They have
-	 * the swapbacked flag cleared, to distinguish them from normal
-	 * anonymous folios
-	 */
-	folio_clear_swapbacked(folio);
-	lruvec_add_folio(lruvec, folio);
-
-	__count_vm_events(PGLAZYFREE, nr_pages);
-	count_memcg_events(lruvec_memcg(lruvec), PGLAZYFREE, nr_pages);
-}
-
-/*
- * Drain pages out of the cpu's folio_batch.
- * Either "cpu" is the current CPU, and preemption has already been
- * disabled; or "cpu" is being hot-unplugged, and is already dead.
- */
-void lru_add_drain_cpu(int cpu)
-{
-	struct cpu_fbatches *fbatches = &per_cpu(cpu_fbatches, cpu);
-	struct folio_batch *fbatch = &fbatches->lru_add;
-
-	if (folio_batch_count(fbatch))
-		folio_batch_move_lru(fbatch, lru_add);
-
-	fbatch = &fbatches->lru_move_tail;
-	/* Disabling interrupts below acts as a compiler barrier. */
-	if (data_race(folio_batch_count(fbatch))) {
-		unsigned long flags;
-
-		/* No harm done if a racing interrupt already did this */
-		local_lock_irqsave(&cpu_fbatches.lock_irq, flags);
-		folio_batch_move_lru(fbatch, lru_move_tail);
-		local_unlock_irqrestore(&cpu_fbatches.lock_irq, flags);
-	}
-
-	fbatch = &fbatches->lru_deactivate_file;
-	if (folio_batch_count(fbatch))
-		folio_batch_move_lru(fbatch, lru_deactivate_file);
-
-	fbatch = &fbatches->lru_deactivate;
-	if (folio_batch_count(fbatch))
-		folio_batch_move_lru(fbatch, lru_deactivate);
-
-	fbatch = &fbatches->lru_lazyfree;
-	if (folio_batch_count(fbatch))
-		folio_batch_move_lru(fbatch, lru_lazyfree);
-
-	folio_activate_drain(cpu);
-}
-
-/**
- * deactivate_file_folio() - Deactivate a file folio.
- * @folio: Folio to deactivate.
- *
- * This function hints to the VM that @folio is a good reclaim candidate,
- * for example if its invalidation fails due to the folio being dirty
- * or under writeback.
- *
- * Context: Caller holds a reference on the folio.
- */
-void deactivate_file_folio(struct folio *folio)
-{
-	/* Deactivating an unevictable folio will not accelerate reclaim */
-	if (folio_test_unevictable(folio) || !folio_test_lru(folio))
-		return;
-
-	if (lru_gen_enabled() && lru_gen_clear_refs(folio))
-		return;
-
-	folio_batch_add_and_move(folio, lru_deactivate_file);
-}
-
-/*
- * folio_deactivate - deactivate a folio
- * @folio: folio to deactivate
- *
- * folio_deactivate() moves @folio to the inactive list if @folio was on the
- * active list and was not unevictable. This is done to accelerate the
- * reclaim of @folio.
- */
-void folio_deactivate(struct folio *folio)
-{
-	if (folio_test_unevictable(folio) || !folio_test_lru(folio))
-		return;
-
-	if (lru_gen_enabled() ? lru_gen_clear_refs(folio) : !folio_test_active(folio))
-		return;
-
-	folio_batch_add_and_move(folio, lru_deactivate);
-}
-
-/**
- * folio_mark_lazyfree - make an anon folio lazyfree
- * @folio: folio to deactivate
- *
- * folio_mark_lazyfree() moves @folio to the inactive file list.
- * This is done to accelerate the reclaim of @folio.
- */
-void folio_mark_lazyfree(struct folio *folio)
-{
-	if (!folio_test_anon(folio) || !folio_test_swapbacked(folio) ||
-	    !folio_test_lru(folio) ||
-	    folio_test_swapcache(folio) || folio_test_unevictable(folio))
-		return;
-
-	folio_batch_add_and_move(folio, lru_lazyfree);
-}
-
-void lru_add_drain(void)
-{
-	local_lock(&cpu_fbatches.lock);
-	lru_add_drain_cpu(smp_processor_id());
-	local_unlock(&cpu_fbatches.lock);
-	mlock_drain_local();
-}
-
-/*
- * It's called from per-cpu workqueue context in SMP case so
- * lru_add_drain_cpu and invalidate_bh_lrus_cpu should run on
- * the same cpu. It shouldn't be a problem in !SMP case since
- * the core is only one and the locks will disable preemption.
- */
-static void lru_add_and_bh_lrus_drain(void)
-{
-	local_lock(&cpu_fbatches.lock);
-	lru_add_drain_cpu(smp_processor_id());
-	local_unlock(&cpu_fbatches.lock);
-	invalidate_bh_lrus_cpu();
-	mlock_drain_local();
-}
-
-void lru_add_drain_cpu_zone(struct zone *zone)
-{
-	local_lock(&cpu_fbatches.lock);
-	lru_add_drain_cpu(smp_processor_id());
-	drain_local_pages(zone);
-	local_unlock(&cpu_fbatches.lock);
-	mlock_drain_local();
-}
-
-#ifdef CONFIG_SMP
-
-static DEFINE_PER_CPU(struct work_struct, lru_add_drain_work);
-
-static void lru_add_drain_per_cpu(struct work_struct *dummy)
-{
-	lru_add_and_bh_lrus_drain();
-}
-
-static bool cpu_needs_drain(unsigned int cpu)
-{
-	struct cpu_fbatches *fbatches = &per_cpu(cpu_fbatches, cpu);
-
-	/* Check these in order of likelihood that they're not zero */
-	return folio_batch_count(&fbatches->lru_add) ||
-		folio_batch_count(&fbatches->lru_move_tail) ||
-		folio_batch_count(&fbatches->lru_deactivate_file) ||
-		folio_batch_count(&fbatches->lru_deactivate) ||
-		folio_batch_count(&fbatches->lru_lazyfree) ||
-		folio_batch_count(&fbatches->lru_activate) ||
-		need_mlock_drain(cpu) ||
-		has_bh_in_lru(cpu, NULL);
-}
-
-/*
- * Doesn't need any cpu hotplug locking because we do rely on per-cpu
- * kworkers being shut down before our page_alloc_cpu_dead callback is
- * executed on the offlined cpu.
- * Calling this function with cpu hotplug locks held can actually lead
- * to obscure indirect dependencies via WQ context.
- */
-static inline void __lru_add_drain_all(bool force_all_cpus)
-{
-	/*
-	 * lru_drain_gen - Global pages generation number
-	 *
-	 * (A) Definition: global lru_drain_gen = x implies that all generations
-	 *     0 < n <= x are already *scheduled* for draining.
-	 *
-	 * This is an optimization for the highly-contended use case where a
-	 * user space workload keeps constantly generating a flow of pages for
-	 * each CPU.
-	 */
-	static unsigned int lru_drain_gen;
-	static struct cpumask has_work;
-	static DEFINE_MUTEX(lock);
-	unsigned cpu, this_gen;
-
-	/*
-	 * Make sure nobody triggers this path before mm_percpu_wq is fully
-	 * initialized.
-	 */
-	if (WARN_ON(!mm_percpu_wq))
-		return;
-
-	/*
-	 * Guarantee folio_batch counter stores visible by this CPU
-	 * are visible to other CPUs before loading the current drain
-	 * generation.
-	 */
-	smp_mb();
-
-	/*
-	 * (B) Locally cache global LRU draining generation number
-	 *
-	 * The read barrier ensures that the counter is loaded before the mutex
-	 * is taken. It pairs with smp_mb() inside the mutex critical section
-	 * at (D).
-	 */
-	this_gen = smp_load_acquire(&lru_drain_gen);
-
-	/* It helps everyone if we do our own local drain immediately. */
-	lru_add_drain();
-
-	mutex_lock(&lock);
-
-	/*
-	 * (C) Exit the draining operation if a newer generation, from another
-	 * lru_add_drain_all(), was already scheduled for draining. Check (A).
-	 */
-	if (unlikely(this_gen != lru_drain_gen && !force_all_cpus))
-		goto done;
-
-	/*
-	 * (D) Increment global generation number
-	 *
-	 * Pairs with smp_load_acquire() at (B), outside of the critical
-	 * section. Use a full memory barrier to guarantee that the
-	 * new global drain generation number is stored before loading
-	 * folio_batch counters.
-	 *
-	 * This pairing must be done here, before the for_each_online_cpu loop
-	 * below which drains the page vectors.
-	 *
-	 * Let x, y, and z represent some system CPU numbers, where x < y < z.
-	 * Assume CPU #z is in the middle of the for_each_online_cpu loop
-	 * below and has already reached CPU #y's per-cpu data. CPU #x comes
-	 * along, adds some pages to its per-cpu vectors, then calls
-	 * lru_add_drain_all().
-	 *
-	 * If the paired barrier is done at any later step, e.g. after the
-	 * loop, CPU #x will just exit at (C) and miss flushing out all of its
-	 * added pages.
-	 */
-	WRITE_ONCE(lru_drain_gen, lru_drain_gen + 1);
-	smp_mb();
-
-	cpumask_clear(&has_work);
-	for_each_online_cpu(cpu) {
-		struct work_struct *work = &per_cpu(lru_add_drain_work, cpu);
-
-		if (cpu_needs_drain(cpu)) {
-			INIT_WORK(work, lru_add_drain_per_cpu);
-			queue_work_on(cpu, mm_percpu_wq, work);
-			__cpumask_set_cpu(cpu, &has_work);
-		}
-	}
-
-	for_each_cpu(cpu, &has_work)
-		flush_work(&per_cpu(lru_add_drain_work, cpu));
-
-done:
-	mutex_unlock(&lock);
-}
-
-void lru_add_drain_all(void)
-{
-	__lru_add_drain_all(false);
-}
-#else
-void lru_add_drain_all(void)
-{
-	lru_add_drain();
-}
-#endif /* CONFIG_SMP */
-
-atomic_t lru_disable_count = ATOMIC_INIT(0);
-
-/*
- * lru_cache_disable() needs to be called before we start compiling
- * a list of folios to be migrated using folio_isolate_lru().
- * It drains folios on LRU cache and then disable on all cpus until
- * lru_cache_enable is called.
- *
- * Must be paired with a call to lru_cache_enable().
- */
-void lru_cache_disable(void)
-{
-	atomic_inc(&lru_disable_count);
-	/*
-	 * Readers of lru_disable_count are protected by either disabling
-	 * preemption or rcu_read_lock:
-	 *
-	 * preempt_disable, local_irq_disable  [bh_lru_lock()]
-	 * rcu_read_lock		       [rt_spin_lock CONFIG_PREEMPT_RT]
-	 * preempt_disable		       [local_lock !CONFIG_PREEMPT_RT]
-	 *
-	 * Since v5.1 kernel, synchronize_rcu() is guaranteed to wait on
-	 * preempt_disable() regions of code. So any CPU which sees
-	 * lru_disable_count = 0 will have exited the critical
-	 * section when synchronize_rcu() returns.
-	 */
-	synchronize_rcu_expedited();
-#ifdef CONFIG_SMP
-	__lru_add_drain_all(true);
-#else
-	lru_add_and_bh_lrus_drain();
-#endif
-}
-
-/**
- * folios_put_refs - Reduce the reference count on a batch of folios.
- * @folios: The folios.
- * @refs: The number of refs to subtract from each folio.
- *
- * Like folio_put(), but for a batch of folios.  This is more efficient
- * than writing the loop yourself as it will optimise the locks which need
- * to be taken if the folios are freed.  The folios batch is returned
- * empty and ready to be reused for another batch; there is no need
- * to reinitialise it.  If @refs is NULL, we subtract one from each
- * folio refcount.
- *
- * Context: May be called in process or interrupt context, but not in NMI
- * context.  May be called while holding a spinlock.
- */
-void folios_put_refs(struct folio_batch *folios, unsigned int *refs)
-{
-	int i, j;
-	struct lruvec *lruvec = NULL;
-	unsigned long flags = 0;
-
-	for (i = 0, j = 0; i < folios->nr; i++) {
-		struct folio *folio = folios->folios[i];
-		unsigned int nr_refs = refs ? refs[i] : 1;
-
-		if (is_huge_zero_folio(folio))
-			continue;
-
-		if (folio_is_zone_device(folio)) {
-			if (lruvec) {
-				unlock_page_lruvec_irqrestore(lruvec, flags);
-				lruvec = NULL;
-			}
-			if (folio_ref_sub_and_test(folio, nr_refs))
-				free_zone_device_folio(folio);
-			continue;
-		}
-
-		if (!folio_ref_sub_and_test(folio, nr_refs))
-			continue;
-
-		/* hugetlb has its own memcg */
-		if (folio_test_hugetlb(folio)) {
-			if (lruvec) {
-				unlock_page_lruvec_irqrestore(lruvec, flags);
-				lruvec = NULL;
-			}
-			free_huge_folio(folio);
-			continue;
-		}
-		folio_unqueue_deferred_split(folio);
-		__page_cache_release(folio, &lruvec, &flags);
-
-		if (j != i)
-			folios->folios[j] = folio;
-		j++;
-	}
-	if (lruvec)
-		unlock_page_lruvec_irqrestore(lruvec, flags);
-	if (!j) {
-		folio_batch_reinit(folios);
-		return;
-	}
-
-	folios->nr = j;
-	mem_cgroup_uncharge_folios(folios);
-	free_unref_folios(folios);
-}
-EXPORT_SYMBOL(folios_put_refs);
-
-/**
- * release_pages - batched put_page()
- * @arg: array of pages to release
- * @nr: number of pages
- *
- * Decrement the reference count on all the pages in @arg.  If it
- * fell to zero, remove the page from the LRU and free it.
- *
- * Note that the argument can be an array of pages, encoded pages,
- * or folio pointers. We ignore any encoded bits, and turn any of
- * them into just a folio that gets free'd.
- */
-void release_pages(release_pages_arg arg, int nr)
-{
-	struct folio_batch fbatch;
-	int refs[PAGEVEC_SIZE];
-	struct encoded_page **encoded = arg.encoded_pages;
-	int i;
-
-	folio_batch_init(&fbatch);
-	for (i = 0; i < nr; i++) {
-		/* Turn any of the argument types into a folio */
-		struct folio *folio = page_folio(encoded_page_ptr(encoded[i]));
-
-		/* Is our next entry actually "nr_pages" -> "nr_refs" ? */
-		refs[fbatch.nr] = 1;
-		if (unlikely(encoded_page_flags(encoded[i]) &
-			     ENCODED_PAGE_BIT_NR_PAGES_NEXT))
-			refs[fbatch.nr] = encoded_nr_pages(encoded[++i]);
-
-		if (folio_batch_add(&fbatch, folio) > 0)
-			continue;
-		folios_put_refs(&fbatch, refs);
-	}
-
-	if (fbatch.nr)
-		folios_put_refs(&fbatch, refs);
-}
-EXPORT_SYMBOL(release_pages);
-
-/*
- * The folios which we're about to release may be in the deferred lru-addition
- * queues.  That would prevent them from really being freed right now.  That's
- * OK from a correctness point of view but is inefficient - those folios may be
- * cache-warm and we want to give them back to the page allocator ASAP.
- *
- * So __folio_batch_release() will drain those queues here.
- * folio_batch_move_lru() calls folios_put() directly to avoid
- * mutual recursion.
- */
-void __folio_batch_release(struct folio_batch *fbatch)
-{
-	if (!fbatch->percpu_pvec_drained) {
-		lru_add_drain();
-		fbatch->percpu_pvec_drained = true;
-	}
-	folios_put(fbatch);
-}
-EXPORT_SYMBOL(__folio_batch_release);
-
-/**
- * folio_batch_remove_exceptionals() - Prune non-folios from a batch.
- * @fbatch: The batch to prune
- *
- * find_get_entries() fills a batch with both folios and shadow/swap/DAX
- * entries.  This function prunes all the non-folio entries from @fbatch
- * without leaving holes, so that it can be passed on to folio-only batch
- * operations.
- */
-void folio_batch_remove_exceptionals(struct folio_batch *fbatch)
-{
-	unsigned int i, j;
-
-	for (i = 0, j = 0; i < folio_batch_count(fbatch); i++) {
-		struct folio *folio = fbatch->folios[i];
-		if (!xa_is_value(folio))
-			fbatch->folios[j++] = folio;
-	}
-	fbatch->nr = j;
-}
-
 static const struct ctl_table swap_sysctl_table[] = {
 	{
 		.procname	= "page-cluster",
--
2.43.0