* [to-be-updated] mm-rename-swapc-to-folioc.patch removed from -mm tree
@ 2026-07-07 18:31 Andrew Morton
0 siblings, 0 replies; only message in thread
From: Andrew Morton @ 2026-07-07 18:31 UTC (permalink / raw)
To: mm-commits, wujianyue000, akpm
The quilt patch titled
Subject: mm: rename swap.c to folio.c
has been removed from the -mm tree. Its filename was
mm-rename-swapc-to-folioc.patch
This patch was dropped because an updated version will be issued
------------------------------------------------------
From: Jianyue Wu <wujianyue000@gmail.com>
Subject: mm: rename swap.c to folio.c
Date: Sun, 05 Jul 2026 22:12:32 +0800
Rename mm/swap.c to mm/folio.c so the filename better matches the code's
main responsibility.
This keeps the implementation split from swap-specific code without
changing the published LRU helper interfaces.
Update MAINTAINERS and the remaining mm/swap.c documentation references
after the rename.
Link: https://lore.kernel.org/20260705-ch-swap-series-plus-folio-lru-cleanup-v7-2-a028e8b5fc3d@gmail.com
Signed-off-by: Jianyue Wu <wujianyue000@gmail.com>
Suggested-by: Baoquan He <bhe@redhat.com>
Suggested-by: David Hildenbrand <david@kernel.org>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
Documentation/admin-guide/sysctl/vm.rst | 3
Documentation/core-api/mm-api.rst | 2
MAINTAINERS | 3
mm/Makefile | 2
mm/folio.c | 1171 +++++++++++++++++++++
mm/swap.c | 1175 ----------------------
6 files changed, 1174 insertions(+), 1182 deletions(-)
--- a/Documentation/admin-guide/sysctl/vm.rst~mm-rename-swapc-to-folioc
+++ a/Documentation/admin-guide/sysctl/vm.rst
@@ -19,9 +19,6 @@ The files in this directory can be used
of the virtual memory (VM) subsystem of the Linux kernel and
the writeout of dirty data to disk.
-Default values and initialization routines for most of these
-files can be found in mm/swap.c.
-
Currently, these files are in /proc/sys/vm:
- admin_reserve_kbytes
--- a/Documentation/core-api/mm-api.rst~mm-rename-swapc-to-folioc
+++ a/Documentation/core-api/mm-api.rst
@@ -118,7 +118,7 @@ More Memory Management Functions
.. #kernel-doc:: mm/hmm.c (build warnings)
.. kernel-doc:: mm/memremap.c
.. kernel-doc:: mm/hugetlb.c
-.. kernel-doc:: mm/swap.c
+.. kernel-doc:: mm/folio.c
.. kernel-doc:: mm/memcontrol.c
.. #kernel-doc:: mm/memory-tiers.c (build warnings)
.. kernel-doc:: mm/shmem.c
--- a/MAINTAINERS~mm-rename-swapc-to-folioc
+++ a/MAINTAINERS
@@ -17085,7 +17085,7 @@ F: Documentation/admin-guide/mm/multigen
F: Documentation/mm/multigen_lru.rst
F: include/linux/mm_inline.h
F: include/linux/mmzone.h
-F: mm/swap.c
+F: mm/folio.c
F: mm/vmscan.c
F: mm/workingset.c
@@ -17237,7 +17237,6 @@ F: include/linux/swap.h
F: include/linux/swapfile.h
F: include/linux/swapops.h
F: mm/page_io.c
-F: mm/swap.c
F: mm/swap.h
F: mm/swap_table.h
F: mm/swap_state.c
diff --git a/mm/folio.c a/mm/folio.c
new file mode 100664
--- /dev/null
+++ a/mm/folio.c
@@ -0,0 +1,1171 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/mm/folio.c
+ *
+ * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
+ */
+
+/*
+ * Folio LRU helpers: add/remove folios from LRU lists, batching,
+ * activation/deactivation, and page cache release paths.
+ */
+
+#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/folio_batch.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"
+#include "page_alloc.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 - 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)
+ lruvec_unlock_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;
+ struct folio_batch free_fbatch;
+ bool is_lru_add = (move_fn == lru_add);
+
+ /*
+ * If we're adding to the LRU, preemptively filter dead folios. Use
+ * this dedicated folio batch for temp storage and deferred cleanup.
+ */
+ if (is_lru_add)
+ folio_batch_init(&free_fbatch);
+
+ 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 (!is_lru_add && !folio_test_clear_lru(folio))
+ continue;
+
+ /*
+ * Filter dead folios by moving them from the add batch to the temp
+ * batch for freeing after this loop.
+ *
+ * We're bypassing normal cleanup. Clear flags that are not
+ * applicable to dead folios.
+ *
+ * Since the folio may be part of a huge page, unqueue from
+ * deferred split list to avoid a dangling list entry.
+ */
+ if (is_lru_add && folio_ref_freeze(folio, 1)) {
+ __folio_clear_active(folio);
+ __folio_clear_unevictable(folio);
+ folio_unqueue_deferred_split(folio);
+ fbatch->folios[i] = NULL;
+ folio_batch_add(&free_fbatch, folio);
+ continue;
+ }
+
+ folio_lruvec_relock_irqsave(folio, &lruvec, &flags);
+ move_fn(lruvec, folio);
+
+ folio_set_lru(folio);
+ }
+
+ if (lruvec)
+ lruvec_unlock_irqrestore(lruvec, flags);
+
+ /* Cleanup filtered dead folios. */
+ if (is_lru_add) {
+ mem_cgroup_uncharge_folios(&free_fbatch);
+ free_unref_folios(&free_fbatch);
+ }
+
+ 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)
+ __releases(rcu)
+{
+ 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);
+ rcu_read_unlock();
+ 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) {
+ rcu_read_unlock();
+ 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);
+ lruvec_unlock_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)
+{
+ int gen = folio_lru_gen(folio);
+ int type = folio_is_file_lru(folio);
+ unsigned long seq;
+
+ if (gen < 0)
+ return true;
+
+ set_mask_bits(&folio->flags.f, LRU_REFS_FLAGS | BIT(PG_workingset), 0);
+
+ rcu_read_lock();
+ seq = READ_ONCE(folio_lruvec(folio)->lrugen.min_seq[type]);
+ rcu_read_unlock();
+ /* whether can do without shuffling under the LRU lock */
+ return gen == lru_gen_from_seq(seq);
+}
+
+#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);
+
+ /*
+ * For refaulted workingset folios, set PG_active so they
+ * can be added to active generations.
+ * For prefaulted file folios, folio_mark_accessed() sets
+ * PG_referenced so lru_gen_folio_seq() places them into
+ * the second oldest generation.
+ */
+ if (lru_gen_enabled() && !folio_test_unevictable(folio) &&
+ lru_gen_in_fault() && !(current->flags & PF_MEMALLOC)) {
+ if (folio_test_workingset(folio))
+ folio_set_active(folio);
+ else if (!folio_test_referenced(folio))
+ folio_mark_accessed(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;
+ unsigned int nr_folios = folio_batch_count(fbatch);
+
+ if (nr_folios) {
+ folio_batch_move_lru(fbatch, lru_add);
+ trace_mm_lru_add_drain_tp(cpu, nr_folios);
+ }
+
+ 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 data_race(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;
+
+ trace_mm_lru_add_drain_all_tp(force_all_cpus);
+
+ /*
+ * 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;
+
+ /* Folio batch entry may have been preemptively removed during drain. */
+ if (!folio)
+ continue;
+
+ if (is_huge_zero_folio(folio))
+ continue;
+
+ if (folio_is_zone_device(folio)) {
+ if (lruvec) {
+ lruvec_unlock_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) {
+ lruvec_unlock_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)
+ lruvec_unlock_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[FOLIO_BATCH_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;
+}
+
+#ifdef CONFIG_MEMCG
+static void lruvec_reparent_lru(struct lruvec *child_lruvec,
+ struct lruvec *parent_lruvec,
+ enum lru_list lru, int nid)
+{
+ int zid;
+ struct zone *zone;
+
+ if (lru != LRU_UNEVICTABLE)
+ list_splice_tail_init(&child_lruvec->lists[lru], &parent_lruvec->lists[lru]);
+
+ for_each_managed_zone_pgdat(zone, NODE_DATA(nid), zid, MAX_NR_ZONES - 1) {
+ unsigned long size = mem_cgroup_get_zone_lru_size(child_lruvec, lru, zid);
+
+ mem_cgroup_update_lru_size(parent_lruvec, lru, zid, size);
+ }
+}
+
+void lru_reparent_memcg(struct mem_cgroup *memcg, struct mem_cgroup *parent, int nid)
+{
+ enum lru_list lru;
+ struct lruvec *child_lruvec, *parent_lruvec;
+
+ child_lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid));
+ parent_lruvec = mem_cgroup_lruvec(parent, NODE_DATA(nid));
+ parent_lruvec->anon_cost += child_lruvec->anon_cost;
+ parent_lruvec->file_cost += child_lruvec->file_cost;
+
+ for_each_lru(lru)
+ lruvec_reparent_lru(child_lruvec, parent_lruvec, lru, nid);
+}
+#endif
--- a/mm/Makefile~mm-rename-swapc-to-folioc
+++ a/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.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/swap.c a/mm/swap.c
deleted file mode 100644
--- a/mm/swap.c
+++ /dev/null
@@ -1,1175 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * linux/mm/swap.c
- *
- * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
- */
-
-/*
- * This file contains the default values for the operation of the
- * Linux VM subsystem. Fine-tuning documentation can be found in
- * Documentation/admin-guide/sysctl/vm.rst.
- * Started 18.12.91
- * Swap aging added 23.2.95, Stephen Tweedie.
- * Buffermem limits added 12.3.98, Rik van Riel.
- */
-
-#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/folio_batch.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"
-#include "page_alloc.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 - 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)
- lruvec_unlock_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;
- struct folio_batch free_fbatch;
- bool is_lru_add = (move_fn == lru_add);
-
- /*
- * If we're adding to the LRU, preemptively filter dead folios. Use
- * this dedicated folio batch for temp storage and deferred cleanup.
- */
- if (is_lru_add)
- folio_batch_init(&free_fbatch);
-
- 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 (!is_lru_add && !folio_test_clear_lru(folio))
- continue;
-
- /*
- * Filter dead folios by moving them from the add batch to the temp
- * batch for freeing after this loop.
- *
- * We're bypassing normal cleanup. Clear flags that are not
- * applicable to dead folios.
- *
- * Since the folio may be part of a huge page, unqueue from
- * deferred split list to avoid a dangling list entry.
- */
- if (is_lru_add && folio_ref_freeze(folio, 1)) {
- __folio_clear_active(folio);
- __folio_clear_unevictable(folio);
- folio_unqueue_deferred_split(folio);
- fbatch->folios[i] = NULL;
- folio_batch_add(&free_fbatch, folio);
- continue;
- }
-
- folio_lruvec_relock_irqsave(folio, &lruvec, &flags);
- move_fn(lruvec, folio);
-
- folio_set_lru(folio);
- }
-
- if (lruvec)
- lruvec_unlock_irqrestore(lruvec, flags);
-
- /* Cleanup filtered dead folios. */
- if (is_lru_add) {
- mem_cgroup_uncharge_folios(&free_fbatch);
- free_unref_folios(&free_fbatch);
- }
-
- 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)
- __releases(rcu)
-{
- 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);
- rcu_read_unlock();
- 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) {
- rcu_read_unlock();
- 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);
- lruvec_unlock_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)
-{
- int gen = folio_lru_gen(folio);
- int type = folio_is_file_lru(folio);
- unsigned long seq;
-
- if (gen < 0)
- return true;
-
- set_mask_bits(&folio->flags.f, LRU_REFS_FLAGS | BIT(PG_workingset), 0);
-
- rcu_read_lock();
- seq = READ_ONCE(folio_lruvec(folio)->lrugen.min_seq[type]);
- rcu_read_unlock();
- /* whether can do without shuffling under the LRU lock */
- return gen == lru_gen_from_seq(seq);
-}
-
-#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);
-
- /*
- * For refaulted workingset folios, set PG_active so they
- * can be added to active generations.
- * For prefaulted file folios, folio_mark_accessed() sets
- * PG_referenced so lru_gen_folio_seq() places them into
- * the second oldest generation.
- */
- if (lru_gen_enabled() && !folio_test_unevictable(folio) &&
- lru_gen_in_fault() && !(current->flags & PF_MEMALLOC)) {
- if (folio_test_workingset(folio))
- folio_set_active(folio);
- else if (!folio_test_referenced(folio))
- folio_mark_accessed(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;
- unsigned int nr_folios = folio_batch_count(fbatch);
-
- if (nr_folios) {
- folio_batch_move_lru(fbatch, lru_add);
- trace_mm_lru_add_drain_tp(cpu, nr_folios);
- }
-
- 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 data_race(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;
-
- trace_mm_lru_add_drain_all_tp(force_all_cpus);
-
- /*
- * 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;
-
- /* Folio batch entry may have been preemptively removed during drain. */
- if (!folio)
- continue;
-
- if (is_huge_zero_folio(folio))
- continue;
-
- if (folio_is_zone_device(folio)) {
- if (lruvec) {
- lruvec_unlock_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) {
- lruvec_unlock_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)
- lruvec_unlock_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[FOLIO_BATCH_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;
-}
-
-#ifdef CONFIG_MEMCG
-static void lruvec_reparent_lru(struct lruvec *child_lruvec,
- struct lruvec *parent_lruvec,
- enum lru_list lru, int nid)
-{
- int zid;
- struct zone *zone;
-
- if (lru != LRU_UNEVICTABLE)
- list_splice_tail_init(&child_lruvec->lists[lru], &parent_lruvec->lists[lru]);
-
- for_each_managed_zone_pgdat(zone, NODE_DATA(nid), zid, MAX_NR_ZONES - 1) {
- unsigned long size = mem_cgroup_get_zone_lru_size(child_lruvec, lru, zid);
-
- mem_cgroup_update_lru_size(parent_lruvec, lru, zid, size);
- }
-}
-
-void lru_reparent_memcg(struct mem_cgroup *memcg, struct mem_cgroup *parent, int nid)
-{
- enum lru_list lru;
- struct lruvec *child_lruvec, *parent_lruvec;
-
- child_lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid));
- parent_lruvec = mem_cgroup_lruvec(parent, NODE_DATA(nid));
- parent_lruvec->anon_cost += child_lruvec->anon_cost;
- parent_lruvec->file_cost += child_lruvec->file_cost;
-
- for_each_lru(lru)
- lruvec_reparent_lru(child_lruvec, parent_lruvec, lru, nid);
-}
-#endif
_
Patches currently in -mm which might be from wujianyue000@gmail.com are
mm-move-reclaim-internal-declarations-out-of-swaph.patch
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2026-07-07 18:31 [to-be-updated] mm-rename-swapc-to-folioc.patch removed from -mm tree Andrew Morton
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