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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /mm/migrate.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'mm/migrate.c')
-rw-r--r--mm/migrate.c2237
1 files changed, 2237 insertions, 0 deletions
diff --git a/mm/migrate.c b/mm/migrate.c
new file mode 100644
index 000000000..c93dd6a31
--- /dev/null
+++ b/mm/migrate.c
@@ -0,0 +1,2237 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Memory Migration functionality - linux/mm/migrate.c
+ *
+ * Copyright (C) 2006 Silicon Graphics, Inc., Christoph Lameter
+ *
+ * Page migration was first developed in the context of the memory hotplug
+ * project. The main authors of the migration code are:
+ *
+ * IWAMOTO Toshihiro <iwamoto@valinux.co.jp>
+ * Hirokazu Takahashi <taka@valinux.co.jp>
+ * Dave Hansen <haveblue@us.ibm.com>
+ * Christoph Lameter
+ */
+
+#include <linux/migrate.h>
+#include <linux/export.h>
+#include <linux/swap.h>
+#include <linux/swapops.h>
+#include <linux/pagemap.h>
+#include <linux/buffer_head.h>
+#include <linux/mm_inline.h>
+#include <linux/nsproxy.h>
+#include <linux/pagevec.h>
+#include <linux/ksm.h>
+#include <linux/rmap.h>
+#include <linux/topology.h>
+#include <linux/cpu.h>
+#include <linux/cpuset.h>
+#include <linux/writeback.h>
+#include <linux/mempolicy.h>
+#include <linux/vmalloc.h>
+#include <linux/security.h>
+#include <linux/backing-dev.h>
+#include <linux/compaction.h>
+#include <linux/syscalls.h>
+#include <linux/compat.h>
+#include <linux/hugetlb.h>
+#include <linux/hugetlb_cgroup.h>
+#include <linux/gfp.h>
+#include <linux/pfn_t.h>
+#include <linux/memremap.h>
+#include <linux/userfaultfd_k.h>
+#include <linux/balloon_compaction.h>
+#include <linux/page_idle.h>
+#include <linux/page_owner.h>
+#include <linux/sched/mm.h>
+#include <linux/ptrace.h>
+#include <linux/oom.h>
+#include <linux/memory.h>
+#include <linux/random.h>
+#include <linux/sched/sysctl.h>
+#include <linux/memory-tiers.h>
+
+#include <asm/tlbflush.h>
+
+#include <trace/events/migrate.h>
+
+#include "internal.h"
+
+int isolate_movable_page(struct page *page, isolate_mode_t mode)
+{
+ const struct movable_operations *mops;
+
+ /*
+ * Avoid burning cycles with pages that are yet under __free_pages(),
+ * or just got freed under us.
+ *
+ * In case we 'win' a race for a movable page being freed under us and
+ * raise its refcount preventing __free_pages() from doing its job
+ * the put_page() at the end of this block will take care of
+ * release this page, thus avoiding a nasty leakage.
+ */
+ if (unlikely(!get_page_unless_zero(page)))
+ goto out;
+
+ /*
+ * Check PageMovable before holding a PG_lock because page's owner
+ * assumes anybody doesn't touch PG_lock of newly allocated page
+ * so unconditionally grabbing the lock ruins page's owner side.
+ */
+ if (unlikely(!__PageMovable(page)))
+ goto out_putpage;
+ /*
+ * As movable pages are not isolated from LRU lists, concurrent
+ * compaction threads can race against page migration functions
+ * as well as race against the releasing a page.
+ *
+ * In order to avoid having an already isolated movable page
+ * being (wrongly) re-isolated while it is under migration,
+ * or to avoid attempting to isolate pages being released,
+ * lets be sure we have the page lock
+ * before proceeding with the movable page isolation steps.
+ */
+ if (unlikely(!trylock_page(page)))
+ goto out_putpage;
+
+ if (!PageMovable(page) || PageIsolated(page))
+ goto out_no_isolated;
+
+ mops = page_movable_ops(page);
+ VM_BUG_ON_PAGE(!mops, page);
+
+ if (!mops->isolate_page(page, mode))
+ goto out_no_isolated;
+
+ /* Driver shouldn't use PG_isolated bit of page->flags */
+ WARN_ON_ONCE(PageIsolated(page));
+ SetPageIsolated(page);
+ unlock_page(page);
+
+ return 0;
+
+out_no_isolated:
+ unlock_page(page);
+out_putpage:
+ put_page(page);
+out:
+ return -EBUSY;
+}
+
+static void putback_movable_page(struct page *page)
+{
+ const struct movable_operations *mops = page_movable_ops(page);
+
+ mops->putback_page(page);
+ ClearPageIsolated(page);
+}
+
+/*
+ * Put previously isolated pages back onto the appropriate lists
+ * from where they were once taken off for compaction/migration.
+ *
+ * This function shall be used whenever the isolated pageset has been
+ * built from lru, balloon, hugetlbfs page. See isolate_migratepages_range()
+ * and isolate_hugetlb().
+ */
+void putback_movable_pages(struct list_head *l)
+{
+ struct page *page;
+ struct page *page2;
+
+ list_for_each_entry_safe(page, page2, l, lru) {
+ if (unlikely(PageHuge(page))) {
+ putback_active_hugepage(page);
+ continue;
+ }
+ list_del(&page->lru);
+ /*
+ * We isolated non-lru movable page so here we can use
+ * __PageMovable because LRU page's mapping cannot have
+ * PAGE_MAPPING_MOVABLE.
+ */
+ if (unlikely(__PageMovable(page))) {
+ VM_BUG_ON_PAGE(!PageIsolated(page), page);
+ lock_page(page);
+ if (PageMovable(page))
+ putback_movable_page(page);
+ else
+ ClearPageIsolated(page);
+ unlock_page(page);
+ put_page(page);
+ } else {
+ mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON +
+ page_is_file_lru(page), -thp_nr_pages(page));
+ putback_lru_page(page);
+ }
+ }
+}
+
+/*
+ * Restore a potential migration pte to a working pte entry
+ */
+static bool remove_migration_pte(struct folio *folio,
+ struct vm_area_struct *vma, unsigned long addr, void *old)
+{
+ DEFINE_FOLIO_VMA_WALK(pvmw, old, vma, addr, PVMW_SYNC | PVMW_MIGRATION);
+
+ while (page_vma_mapped_walk(&pvmw)) {
+ rmap_t rmap_flags = RMAP_NONE;
+ pte_t pte;
+ swp_entry_t entry;
+ struct page *new;
+ unsigned long idx = 0;
+
+ /* pgoff is invalid for ksm pages, but they are never large */
+ if (folio_test_large(folio) && !folio_test_hugetlb(folio))
+ idx = linear_page_index(vma, pvmw.address) - pvmw.pgoff;
+ new = folio_page(folio, idx);
+
+#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
+ /* PMD-mapped THP migration entry */
+ if (!pvmw.pte) {
+ VM_BUG_ON_FOLIO(folio_test_hugetlb(folio) ||
+ !folio_test_pmd_mappable(folio), folio);
+ remove_migration_pmd(&pvmw, new);
+ continue;
+ }
+#endif
+
+ folio_get(folio);
+ pte = mk_pte(new, READ_ONCE(vma->vm_page_prot));
+ if (pte_swp_soft_dirty(*pvmw.pte))
+ pte = pte_mksoft_dirty(pte);
+
+ /*
+ * Recheck VMA as permissions can change since migration started
+ */
+ entry = pte_to_swp_entry(*pvmw.pte);
+ if (!is_migration_entry_young(entry))
+ pte = pte_mkold(pte);
+ if (folio_test_dirty(folio) && is_migration_entry_dirty(entry))
+ pte = pte_mkdirty(pte);
+ if (is_writable_migration_entry(entry))
+ pte = maybe_mkwrite(pte, vma);
+ else if (pte_swp_uffd_wp(*pvmw.pte))
+ pte = pte_mkuffd_wp(pte);
+ else
+ pte = pte_wrprotect(pte);
+
+ if (folio_test_anon(folio) && !is_readable_migration_entry(entry))
+ rmap_flags |= RMAP_EXCLUSIVE;
+
+ if (unlikely(is_device_private_page(new))) {
+ if (pte_write(pte))
+ entry = make_writable_device_private_entry(
+ page_to_pfn(new));
+ else
+ entry = make_readable_device_private_entry(
+ page_to_pfn(new));
+ pte = swp_entry_to_pte(entry);
+ if (pte_swp_soft_dirty(*pvmw.pte))
+ pte = pte_swp_mksoft_dirty(pte);
+ if (pte_swp_uffd_wp(*pvmw.pte))
+ pte = pte_swp_mkuffd_wp(pte);
+ }
+
+#ifdef CONFIG_HUGETLB_PAGE
+ if (folio_test_hugetlb(folio)) {
+ unsigned int shift = huge_page_shift(hstate_vma(vma));
+
+ pte = pte_mkhuge(pte);
+ pte = arch_make_huge_pte(pte, shift, vma->vm_flags);
+ if (folio_test_anon(folio))
+ hugepage_add_anon_rmap(new, vma, pvmw.address,
+ rmap_flags);
+ else
+ page_dup_file_rmap(new, true);
+ set_huge_pte_at(vma->vm_mm, pvmw.address, pvmw.pte, pte);
+ } else
+#endif
+ {
+ if (folio_test_anon(folio))
+ page_add_anon_rmap(new, vma, pvmw.address,
+ rmap_flags);
+ else
+ page_add_file_rmap(new, vma, false);
+ set_pte_at(vma->vm_mm, pvmw.address, pvmw.pte, pte);
+ }
+ if (vma->vm_flags & VM_LOCKED)
+ mlock_page_drain_local();
+
+ trace_remove_migration_pte(pvmw.address, pte_val(pte),
+ compound_order(new));
+
+ /* No need to invalidate - it was non-present before */
+ update_mmu_cache(vma, pvmw.address, pvmw.pte);
+ }
+
+ return true;
+}
+
+/*
+ * Get rid of all migration entries and replace them by
+ * references to the indicated page.
+ */
+void remove_migration_ptes(struct folio *src, struct folio *dst, bool locked)
+{
+ struct rmap_walk_control rwc = {
+ .rmap_one = remove_migration_pte,
+ .arg = src,
+ };
+
+ if (locked)
+ rmap_walk_locked(dst, &rwc);
+ else
+ rmap_walk(dst, &rwc);
+}
+
+/*
+ * Something used the pte of a page under migration. We need to
+ * get to the page and wait until migration is finished.
+ * When we return from this function the fault will be retried.
+ */
+void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
+ spinlock_t *ptl)
+{
+ pte_t pte;
+ swp_entry_t entry;
+
+ spin_lock(ptl);
+ pte = *ptep;
+ if (!is_swap_pte(pte))
+ goto out;
+
+ entry = pte_to_swp_entry(pte);
+ if (!is_migration_entry(entry))
+ goto out;
+
+ migration_entry_wait_on_locked(entry, ptep, ptl);
+ return;
+out:
+ pte_unmap_unlock(ptep, ptl);
+}
+
+void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
+ unsigned long address)
+{
+ spinlock_t *ptl = pte_lockptr(mm, pmd);
+ pte_t *ptep = pte_offset_map(pmd, address);
+ __migration_entry_wait(mm, ptep, ptl);
+}
+
+#ifdef CONFIG_HUGETLB_PAGE
+void __migration_entry_wait_huge(pte_t *ptep, spinlock_t *ptl)
+{
+ pte_t pte;
+
+ spin_lock(ptl);
+ pte = huge_ptep_get(ptep);
+
+ if (unlikely(!is_hugetlb_entry_migration(pte)))
+ spin_unlock(ptl);
+ else
+ migration_entry_wait_on_locked(pte_to_swp_entry(pte), NULL, ptl);
+}
+
+void migration_entry_wait_huge(struct vm_area_struct *vma, pte_t *pte)
+{
+ spinlock_t *ptl = huge_pte_lockptr(hstate_vma(vma), vma->vm_mm, pte);
+
+ __migration_entry_wait_huge(pte, ptl);
+}
+#endif
+
+#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
+void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd)
+{
+ spinlock_t *ptl;
+
+ ptl = pmd_lock(mm, pmd);
+ if (!is_pmd_migration_entry(*pmd))
+ goto unlock;
+ migration_entry_wait_on_locked(pmd_to_swp_entry(*pmd), NULL, ptl);
+ return;
+unlock:
+ spin_unlock(ptl);
+}
+#endif
+
+static int folio_expected_refs(struct address_space *mapping,
+ struct folio *folio)
+{
+ int refs = 1;
+ if (!mapping)
+ return refs;
+
+ refs += folio_nr_pages(folio);
+ if (folio_test_private(folio))
+ refs++;
+
+ return refs;
+}
+
+/*
+ * Replace the page in the mapping.
+ *
+ * The number of remaining references must be:
+ * 1 for anonymous pages without a mapping
+ * 2 for pages with a mapping
+ * 3 for pages with a mapping and PagePrivate/PagePrivate2 set.
+ */
+int folio_migrate_mapping(struct address_space *mapping,
+ struct folio *newfolio, struct folio *folio, int extra_count)
+{
+ XA_STATE(xas, &mapping->i_pages, folio_index(folio));
+ struct zone *oldzone, *newzone;
+ int dirty;
+ int expected_count = folio_expected_refs(mapping, folio) + extra_count;
+ long nr = folio_nr_pages(folio);
+ long entries, i;
+
+ if (!mapping) {
+ /* Anonymous page without mapping */
+ if (folio_ref_count(folio) != expected_count)
+ return -EAGAIN;
+
+ /* No turning back from here */
+ newfolio->index = folio->index;
+ newfolio->mapping = folio->mapping;
+ if (folio_test_swapbacked(folio))
+ __folio_set_swapbacked(newfolio);
+
+ return MIGRATEPAGE_SUCCESS;
+ }
+
+ oldzone = folio_zone(folio);
+ newzone = folio_zone(newfolio);
+
+ xas_lock_irq(&xas);
+ if (!folio_ref_freeze(folio, expected_count)) {
+ xas_unlock_irq(&xas);
+ return -EAGAIN;
+ }
+
+ /*
+ * Now we know that no one else is looking at the folio:
+ * no turning back from here.
+ */
+ newfolio->index = folio->index;
+ newfolio->mapping = folio->mapping;
+ folio_ref_add(newfolio, nr); /* add cache reference */
+ if (folio_test_swapbacked(folio)) {
+ __folio_set_swapbacked(newfolio);
+ if (folio_test_swapcache(folio)) {
+ folio_set_swapcache(newfolio);
+ newfolio->private = folio_get_private(folio);
+ }
+ entries = nr;
+ } else {
+ VM_BUG_ON_FOLIO(folio_test_swapcache(folio), folio);
+ entries = 1;
+ }
+
+ /* Move dirty while page refs frozen and newpage not yet exposed */
+ dirty = folio_test_dirty(folio);
+ if (dirty) {
+ folio_clear_dirty(folio);
+ folio_set_dirty(newfolio);
+ }
+
+ /* Swap cache still stores N entries instead of a high-order entry */
+ for (i = 0; i < entries; i++) {
+ xas_store(&xas, newfolio);
+ xas_next(&xas);
+ }
+
+ /*
+ * Drop cache reference from old page by unfreezing
+ * to one less reference.
+ * We know this isn't the last reference.
+ */
+ folio_ref_unfreeze(folio, expected_count - nr);
+
+ xas_unlock(&xas);
+ /* Leave irq disabled to prevent preemption while updating stats */
+
+ /*
+ * If moved to a different zone then also account
+ * the page for that zone. Other VM counters will be
+ * taken care of when we establish references to the
+ * new page and drop references to the old page.
+ *
+ * Note that anonymous pages are accounted for
+ * via NR_FILE_PAGES and NR_ANON_MAPPED if they
+ * are mapped to swap space.
+ */
+ if (newzone != oldzone) {
+ struct lruvec *old_lruvec, *new_lruvec;
+ struct mem_cgroup *memcg;
+
+ memcg = folio_memcg(folio);
+ old_lruvec = mem_cgroup_lruvec(memcg, oldzone->zone_pgdat);
+ new_lruvec = mem_cgroup_lruvec(memcg, newzone->zone_pgdat);
+
+ __mod_lruvec_state(old_lruvec, NR_FILE_PAGES, -nr);
+ __mod_lruvec_state(new_lruvec, NR_FILE_PAGES, nr);
+ if (folio_test_swapbacked(folio) && !folio_test_swapcache(folio)) {
+ __mod_lruvec_state(old_lruvec, NR_SHMEM, -nr);
+ __mod_lruvec_state(new_lruvec, NR_SHMEM, nr);
+ }
+#ifdef CONFIG_SWAP
+ if (folio_test_swapcache(folio)) {
+ __mod_lruvec_state(old_lruvec, NR_SWAPCACHE, -nr);
+ __mod_lruvec_state(new_lruvec, NR_SWAPCACHE, nr);
+ }
+#endif
+ if (dirty && mapping_can_writeback(mapping)) {
+ __mod_lruvec_state(old_lruvec, NR_FILE_DIRTY, -nr);
+ __mod_zone_page_state(oldzone, NR_ZONE_WRITE_PENDING, -nr);
+ __mod_lruvec_state(new_lruvec, NR_FILE_DIRTY, nr);
+ __mod_zone_page_state(newzone, NR_ZONE_WRITE_PENDING, nr);
+ }
+ }
+ local_irq_enable();
+
+ return MIGRATEPAGE_SUCCESS;
+}
+EXPORT_SYMBOL(folio_migrate_mapping);
+
+/*
+ * The expected number of remaining references is the same as that
+ * of folio_migrate_mapping().
+ */
+int migrate_huge_page_move_mapping(struct address_space *mapping,
+ struct folio *dst, struct folio *src)
+{
+ XA_STATE(xas, &mapping->i_pages, folio_index(src));
+ int expected_count;
+
+ xas_lock_irq(&xas);
+ expected_count = 2 + folio_has_private(src);
+ if (!folio_ref_freeze(src, expected_count)) {
+ xas_unlock_irq(&xas);
+ return -EAGAIN;
+ }
+
+ dst->index = src->index;
+ dst->mapping = src->mapping;
+
+ folio_get(dst);
+
+ xas_store(&xas, dst);
+
+ folio_ref_unfreeze(src, expected_count - 1);
+
+ xas_unlock_irq(&xas);
+
+ return MIGRATEPAGE_SUCCESS;
+}
+
+/*
+ * Copy the flags and some other ancillary information
+ */
+void folio_migrate_flags(struct folio *newfolio, struct folio *folio)
+{
+ int cpupid;
+
+ if (folio_test_error(folio))
+ folio_set_error(newfolio);
+ if (folio_test_referenced(folio))
+ folio_set_referenced(newfolio);
+ if (folio_test_uptodate(folio))
+ folio_mark_uptodate(newfolio);
+ if (folio_test_clear_active(folio)) {
+ VM_BUG_ON_FOLIO(folio_test_unevictable(folio), folio);
+ folio_set_active(newfolio);
+ } else if (folio_test_clear_unevictable(folio))
+ folio_set_unevictable(newfolio);
+ if (folio_test_workingset(folio))
+ folio_set_workingset(newfolio);
+ if (folio_test_checked(folio))
+ folio_set_checked(newfolio);
+ /*
+ * PG_anon_exclusive (-> PG_mappedtodisk) is always migrated via
+ * migration entries. We can still have PG_anon_exclusive set on an
+ * effectively unmapped and unreferenced first sub-pages of an
+ * anonymous THP: we can simply copy it here via PG_mappedtodisk.
+ */
+ if (folio_test_mappedtodisk(folio))
+ folio_set_mappedtodisk(newfolio);
+
+ /* Move dirty on pages not done by folio_migrate_mapping() */
+ if (folio_test_dirty(folio))
+ folio_set_dirty(newfolio);
+
+ if (folio_test_young(folio))
+ folio_set_young(newfolio);
+ if (folio_test_idle(folio))
+ folio_set_idle(newfolio);
+
+ /*
+ * Copy NUMA information to the new page, to prevent over-eager
+ * future migrations of this same page.
+ */
+ cpupid = page_cpupid_xchg_last(&folio->page, -1);
+ /*
+ * For memory tiering mode, when migrate between slow and fast
+ * memory node, reset cpupid, because that is used to record
+ * page access time in slow memory node.
+ */
+ if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING) {
+ bool f_toptier = node_is_toptier(page_to_nid(&folio->page));
+ bool t_toptier = node_is_toptier(page_to_nid(&newfolio->page));
+
+ if (f_toptier != t_toptier)
+ cpupid = -1;
+ }
+ page_cpupid_xchg_last(&newfolio->page, cpupid);
+
+ folio_migrate_ksm(newfolio, folio);
+ /*
+ * Please do not reorder this without considering how mm/ksm.c's
+ * get_ksm_page() depends upon ksm_migrate_page() and PageSwapCache().
+ */
+ if (folio_test_swapcache(folio))
+ folio_clear_swapcache(folio);
+ folio_clear_private(folio);
+
+ /* page->private contains hugetlb specific flags */
+ if (!folio_test_hugetlb(folio))
+ folio->private = NULL;
+
+ /*
+ * If any waiters have accumulated on the new page then
+ * wake them up.
+ */
+ if (folio_test_writeback(newfolio))
+ folio_end_writeback(newfolio);
+
+ /*
+ * PG_readahead shares the same bit with PG_reclaim. The above
+ * end_page_writeback() may clear PG_readahead mistakenly, so set the
+ * bit after that.
+ */
+ if (folio_test_readahead(folio))
+ folio_set_readahead(newfolio);
+
+ folio_copy_owner(newfolio, folio);
+
+ if (!folio_test_hugetlb(folio))
+ mem_cgroup_migrate(folio, newfolio);
+}
+EXPORT_SYMBOL(folio_migrate_flags);
+
+void folio_migrate_copy(struct folio *newfolio, struct folio *folio)
+{
+ folio_copy(newfolio, folio);
+ folio_migrate_flags(newfolio, folio);
+}
+EXPORT_SYMBOL(folio_migrate_copy);
+
+/************************************************************
+ * Migration functions
+ ***********************************************************/
+
+int migrate_folio_extra(struct address_space *mapping, struct folio *dst,
+ struct folio *src, enum migrate_mode mode, int extra_count)
+{
+ int rc;
+
+ BUG_ON(folio_test_writeback(src)); /* Writeback must be complete */
+
+ rc = folio_migrate_mapping(mapping, dst, src, extra_count);
+
+ if (rc != MIGRATEPAGE_SUCCESS)
+ return rc;
+
+ if (mode != MIGRATE_SYNC_NO_COPY)
+ folio_migrate_copy(dst, src);
+ else
+ folio_migrate_flags(dst, src);
+ return MIGRATEPAGE_SUCCESS;
+}
+
+/**
+ * migrate_folio() - Simple folio migration.
+ * @mapping: The address_space containing the folio.
+ * @dst: The folio to migrate the data to.
+ * @src: The folio containing the current data.
+ * @mode: How to migrate the page.
+ *
+ * Common logic to directly migrate a single LRU folio suitable for
+ * folios that do not use PagePrivate/PagePrivate2.
+ *
+ * Folios are locked upon entry and exit.
+ */
+int migrate_folio(struct address_space *mapping, struct folio *dst,
+ struct folio *src, enum migrate_mode mode)
+{
+ return migrate_folio_extra(mapping, dst, src, mode, 0);
+}
+EXPORT_SYMBOL(migrate_folio);
+
+#ifdef CONFIG_BLOCK
+/* Returns true if all buffers are successfully locked */
+static bool buffer_migrate_lock_buffers(struct buffer_head *head,
+ enum migrate_mode mode)
+{
+ struct buffer_head *bh = head;
+
+ /* Simple case, sync compaction */
+ if (mode != MIGRATE_ASYNC) {
+ do {
+ lock_buffer(bh);
+ bh = bh->b_this_page;
+
+ } while (bh != head);
+
+ return true;
+ }
+
+ /* async case, we cannot block on lock_buffer so use trylock_buffer */
+ do {
+ if (!trylock_buffer(bh)) {
+ /*
+ * We failed to lock the buffer and cannot stall in
+ * async migration. Release the taken locks
+ */
+ struct buffer_head *failed_bh = bh;
+ bh = head;
+ while (bh != failed_bh) {
+ unlock_buffer(bh);
+ bh = bh->b_this_page;
+ }
+ return false;
+ }
+
+ bh = bh->b_this_page;
+ } while (bh != head);
+ return true;
+}
+
+static int __buffer_migrate_folio(struct address_space *mapping,
+ struct folio *dst, struct folio *src, enum migrate_mode mode,
+ bool check_refs)
+{
+ struct buffer_head *bh, *head;
+ int rc;
+ int expected_count;
+
+ head = folio_buffers(src);
+ if (!head)
+ return migrate_folio(mapping, dst, src, mode);
+
+ /* Check whether page does not have extra refs before we do more work */
+ expected_count = folio_expected_refs(mapping, src);
+ if (folio_ref_count(src) != expected_count)
+ return -EAGAIN;
+
+ if (!buffer_migrate_lock_buffers(head, mode))
+ return -EAGAIN;
+
+ if (check_refs) {
+ bool busy;
+ bool invalidated = false;
+
+recheck_buffers:
+ busy = false;
+ spin_lock(&mapping->private_lock);
+ bh = head;
+ do {
+ if (atomic_read(&bh->b_count)) {
+ busy = true;
+ break;
+ }
+ bh = bh->b_this_page;
+ } while (bh != head);
+ if (busy) {
+ if (invalidated) {
+ rc = -EAGAIN;
+ goto unlock_buffers;
+ }
+ spin_unlock(&mapping->private_lock);
+ invalidate_bh_lrus();
+ invalidated = true;
+ goto recheck_buffers;
+ }
+ }
+
+ rc = folio_migrate_mapping(mapping, dst, src, 0);
+ if (rc != MIGRATEPAGE_SUCCESS)
+ goto unlock_buffers;
+
+ folio_attach_private(dst, folio_detach_private(src));
+
+ bh = head;
+ do {
+ set_bh_page(bh, &dst->page, bh_offset(bh));
+ bh = bh->b_this_page;
+ } while (bh != head);
+
+ if (mode != MIGRATE_SYNC_NO_COPY)
+ folio_migrate_copy(dst, src);
+ else
+ folio_migrate_flags(dst, src);
+
+ rc = MIGRATEPAGE_SUCCESS;
+unlock_buffers:
+ if (check_refs)
+ spin_unlock(&mapping->private_lock);
+ bh = head;
+ do {
+ unlock_buffer(bh);
+ bh = bh->b_this_page;
+ } while (bh != head);
+
+ return rc;
+}
+
+/**
+ * buffer_migrate_folio() - Migration function for folios with buffers.
+ * @mapping: The address space containing @src.
+ * @dst: The folio to migrate to.
+ * @src: The folio to migrate from.
+ * @mode: How to migrate the folio.
+ *
+ * This function can only be used if the underlying filesystem guarantees
+ * that no other references to @src exist. For example attached buffer
+ * heads are accessed only under the folio lock. If your filesystem cannot
+ * provide this guarantee, buffer_migrate_folio_norefs() may be more
+ * appropriate.
+ *
+ * Return: 0 on success or a negative errno on failure.
+ */
+int buffer_migrate_folio(struct address_space *mapping,
+ struct folio *dst, struct folio *src, enum migrate_mode mode)
+{
+ return __buffer_migrate_folio(mapping, dst, src, mode, false);
+}
+EXPORT_SYMBOL(buffer_migrate_folio);
+
+/**
+ * buffer_migrate_folio_norefs() - Migration function for folios with buffers.
+ * @mapping: The address space containing @src.
+ * @dst: The folio to migrate to.
+ * @src: The folio to migrate from.
+ * @mode: How to migrate the folio.
+ *
+ * Like buffer_migrate_folio() except that this variant is more careful
+ * and checks that there are also no buffer head references. This function
+ * is the right one for mappings where buffer heads are directly looked
+ * up and referenced (such as block device mappings).
+ *
+ * Return: 0 on success or a negative errno on failure.
+ */
+int buffer_migrate_folio_norefs(struct address_space *mapping,
+ struct folio *dst, struct folio *src, enum migrate_mode mode)
+{
+ return __buffer_migrate_folio(mapping, dst, src, mode, true);
+}
+#endif
+
+int filemap_migrate_folio(struct address_space *mapping,
+ struct folio *dst, struct folio *src, enum migrate_mode mode)
+{
+ int ret;
+
+ ret = folio_migrate_mapping(mapping, dst, src, 0);
+ if (ret != MIGRATEPAGE_SUCCESS)
+ return ret;
+
+ if (folio_get_private(src))
+ folio_attach_private(dst, folio_detach_private(src));
+
+ if (mode != MIGRATE_SYNC_NO_COPY)
+ folio_migrate_copy(dst, src);
+ else
+ folio_migrate_flags(dst, src);
+ return MIGRATEPAGE_SUCCESS;
+}
+EXPORT_SYMBOL_GPL(filemap_migrate_folio);
+
+/*
+ * Writeback a folio to clean the dirty state
+ */
+static int writeout(struct address_space *mapping, struct folio *folio)
+{
+ struct writeback_control wbc = {
+ .sync_mode = WB_SYNC_NONE,
+ .nr_to_write = 1,
+ .range_start = 0,
+ .range_end = LLONG_MAX,
+ .for_reclaim = 1
+ };
+ int rc;
+
+ if (!mapping->a_ops->writepage)
+ /* No write method for the address space */
+ return -EINVAL;
+
+ if (!folio_clear_dirty_for_io(folio))
+ /* Someone else already triggered a write */
+ return -EAGAIN;
+
+ /*
+ * A dirty folio may imply that the underlying filesystem has
+ * the folio on some queue. So the folio must be clean for
+ * migration. Writeout may mean we lose the lock and the
+ * folio state is no longer what we checked for earlier.
+ * At this point we know that the migration attempt cannot
+ * be successful.
+ */
+ remove_migration_ptes(folio, folio, false);
+
+ rc = mapping->a_ops->writepage(&folio->page, &wbc);
+
+ if (rc != AOP_WRITEPAGE_ACTIVATE)
+ /* unlocked. Relock */
+ folio_lock(folio);
+
+ return (rc < 0) ? -EIO : -EAGAIN;
+}
+
+/*
+ * Default handling if a filesystem does not provide a migration function.
+ */
+static int fallback_migrate_folio(struct address_space *mapping,
+ struct folio *dst, struct folio *src, enum migrate_mode mode)
+{
+ if (folio_test_dirty(src)) {
+ /* Only writeback folios in full synchronous migration */
+ switch (mode) {
+ case MIGRATE_SYNC:
+ case MIGRATE_SYNC_NO_COPY:
+ break;
+ default:
+ return -EBUSY;
+ }
+ return writeout(mapping, src);
+ }
+
+ /*
+ * Buffers may be managed in a filesystem specific way.
+ * We must have no buffers or drop them.
+ */
+ if (!filemap_release_folio(src, GFP_KERNEL))
+ return mode == MIGRATE_SYNC ? -EAGAIN : -EBUSY;
+
+ return migrate_folio(mapping, dst, src, mode);
+}
+
+/*
+ * Move a page to a newly allocated page
+ * The page is locked and all ptes have been successfully removed.
+ *
+ * The new page will have replaced the old page if this function
+ * is successful.
+ *
+ * Return value:
+ * < 0 - error code
+ * MIGRATEPAGE_SUCCESS - success
+ */
+static int move_to_new_folio(struct folio *dst, struct folio *src,
+ enum migrate_mode mode)
+{
+ int rc = -EAGAIN;
+ bool is_lru = !__PageMovable(&src->page);
+
+ VM_BUG_ON_FOLIO(!folio_test_locked(src), src);
+ VM_BUG_ON_FOLIO(!folio_test_locked(dst), dst);
+
+ if (likely(is_lru)) {
+ struct address_space *mapping = folio_mapping(src);
+
+ if (!mapping)
+ rc = migrate_folio(mapping, dst, src, mode);
+ else if (mapping->a_ops->migrate_folio)
+ /*
+ * Most folios have a mapping and most filesystems
+ * provide a migrate_folio callback. Anonymous folios
+ * are part of swap space which also has its own
+ * migrate_folio callback. This is the most common path
+ * for page migration.
+ */
+ rc = mapping->a_ops->migrate_folio(mapping, dst, src,
+ mode);
+ else
+ rc = fallback_migrate_folio(mapping, dst, src, mode);
+ } else {
+ const struct movable_operations *mops;
+
+ /*
+ * In case of non-lru page, it could be released after
+ * isolation step. In that case, we shouldn't try migration.
+ */
+ VM_BUG_ON_FOLIO(!folio_test_isolated(src), src);
+ if (!folio_test_movable(src)) {
+ rc = MIGRATEPAGE_SUCCESS;
+ folio_clear_isolated(src);
+ goto out;
+ }
+
+ mops = page_movable_ops(&src->page);
+ rc = mops->migrate_page(&dst->page, &src->page, mode);
+ WARN_ON_ONCE(rc == MIGRATEPAGE_SUCCESS &&
+ !folio_test_isolated(src));
+ }
+
+ /*
+ * When successful, old pagecache src->mapping must be cleared before
+ * src is freed; but stats require that PageAnon be left as PageAnon.
+ */
+ if (rc == MIGRATEPAGE_SUCCESS) {
+ if (__PageMovable(&src->page)) {
+ VM_BUG_ON_FOLIO(!folio_test_isolated(src), src);
+
+ /*
+ * We clear PG_movable under page_lock so any compactor
+ * cannot try to migrate this page.
+ */
+ folio_clear_isolated(src);
+ }
+
+ /*
+ * Anonymous and movable src->mapping will be cleared by
+ * free_pages_prepare so don't reset it here for keeping
+ * the type to work PageAnon, for example.
+ */
+ if (!folio_mapping_flags(src))
+ src->mapping = NULL;
+
+ if (likely(!folio_is_zone_device(dst)))
+ flush_dcache_folio(dst);
+ }
+out:
+ return rc;
+}
+
+static int __unmap_and_move(struct folio *src, struct folio *dst,
+ int force, enum migrate_mode mode)
+{
+ int rc = -EAGAIN;
+ bool page_was_mapped = false;
+ struct anon_vma *anon_vma = NULL;
+ bool is_lru = !__PageMovable(&src->page);
+
+ if (!folio_trylock(src)) {
+ if (!force || mode == MIGRATE_ASYNC)
+ goto out;
+
+ /*
+ * It's not safe for direct compaction to call lock_page.
+ * For example, during page readahead pages are added locked
+ * to the LRU. Later, when the IO completes the pages are
+ * marked uptodate and unlocked. However, the queueing
+ * could be merging multiple pages for one bio (e.g.
+ * mpage_readahead). If an allocation happens for the
+ * second or third page, the process can end up locking
+ * the same page twice and deadlocking. Rather than
+ * trying to be clever about what pages can be locked,
+ * avoid the use of lock_page for direct compaction
+ * altogether.
+ */
+ if (current->flags & PF_MEMALLOC)
+ goto out;
+
+ folio_lock(src);
+ }
+
+ if (folio_test_writeback(src)) {
+ /*
+ * Only in the case of a full synchronous migration is it
+ * necessary to wait for PageWriteback. In the async case,
+ * the retry loop is too short and in the sync-light case,
+ * the overhead of stalling is too much
+ */
+ switch (mode) {
+ case MIGRATE_SYNC:
+ case MIGRATE_SYNC_NO_COPY:
+ break;
+ default:
+ rc = -EBUSY;
+ goto out_unlock;
+ }
+ if (!force)
+ goto out_unlock;
+ folio_wait_writeback(src);
+ }
+
+ /*
+ * By try_to_migrate(), src->mapcount goes down to 0 here. In this case,
+ * we cannot notice that anon_vma is freed while we migrate a page.
+ * This get_anon_vma() delays freeing anon_vma pointer until the end
+ * of migration. File cache pages are no problem because of page_lock()
+ * File Caches may use write_page() or lock_page() in migration, then,
+ * just care Anon page here.
+ *
+ * Only folio_get_anon_vma() understands the subtleties of
+ * getting a hold on an anon_vma from outside one of its mms.
+ * But if we cannot get anon_vma, then we won't need it anyway,
+ * because that implies that the anon page is no longer mapped
+ * (and cannot be remapped so long as we hold the page lock).
+ */
+ if (folio_test_anon(src) && !folio_test_ksm(src))
+ anon_vma = folio_get_anon_vma(src);
+
+ /*
+ * Block others from accessing the new page when we get around to
+ * establishing additional references. We are usually the only one
+ * holding a reference to dst at this point. We used to have a BUG
+ * here if folio_trylock(dst) fails, but would like to allow for
+ * cases where there might be a race with the previous use of dst.
+ * This is much like races on refcount of oldpage: just don't BUG().
+ */
+ if (unlikely(!folio_trylock(dst)))
+ goto out_unlock;
+
+ if (unlikely(!is_lru)) {
+ rc = move_to_new_folio(dst, src, mode);
+ goto out_unlock_both;
+ }
+
+ /*
+ * Corner case handling:
+ * 1. When a new swap-cache page is read into, it is added to the LRU
+ * and treated as swapcache but it has no rmap yet.
+ * Calling try_to_unmap() against a src->mapping==NULL page will
+ * trigger a BUG. So handle it here.
+ * 2. An orphaned page (see truncate_cleanup_page) might have
+ * fs-private metadata. The page can be picked up due to memory
+ * offlining. Everywhere else except page reclaim, the page is
+ * invisible to the vm, so the page can not be migrated. So try to
+ * free the metadata, so the page can be freed.
+ */
+ if (!src->mapping) {
+ if (folio_test_private(src)) {
+ try_to_free_buffers(src);
+ goto out_unlock_both;
+ }
+ } else if (folio_mapped(src)) {
+ /* Establish migration ptes */
+ VM_BUG_ON_FOLIO(folio_test_anon(src) &&
+ !folio_test_ksm(src) && !anon_vma, src);
+ try_to_migrate(src, 0);
+ page_was_mapped = true;
+ }
+
+ if (!folio_mapped(src))
+ rc = move_to_new_folio(dst, src, mode);
+
+ /*
+ * When successful, push dst to LRU immediately: so that if it
+ * turns out to be an mlocked page, remove_migration_ptes() will
+ * automatically build up the correct dst->mlock_count for it.
+ *
+ * We would like to do something similar for the old page, when
+ * unsuccessful, and other cases when a page has been temporarily
+ * isolated from the unevictable LRU: but this case is the easiest.
+ */
+ if (rc == MIGRATEPAGE_SUCCESS) {
+ folio_add_lru(dst);
+ if (page_was_mapped)
+ lru_add_drain();
+ }
+
+ if (page_was_mapped)
+ remove_migration_ptes(src,
+ rc == MIGRATEPAGE_SUCCESS ? dst : src, false);
+
+out_unlock_both:
+ folio_unlock(dst);
+out_unlock:
+ /* Drop an anon_vma reference if we took one */
+ if (anon_vma)
+ put_anon_vma(anon_vma);
+ folio_unlock(src);
+out:
+ /*
+ * If migration is successful, decrease refcount of dst,
+ * which will not free the page because new page owner increased
+ * refcounter.
+ */
+ if (rc == MIGRATEPAGE_SUCCESS)
+ folio_put(dst);
+
+ return rc;
+}
+
+/*
+ * Obtain the lock on page, remove all ptes and migrate the page
+ * to the newly allocated page in newpage.
+ */
+static int unmap_and_move(new_page_t get_new_page,
+ free_page_t put_new_page,
+ unsigned long private, struct page *page,
+ int force, enum migrate_mode mode,
+ enum migrate_reason reason,
+ struct list_head *ret)
+{
+ struct folio *dst, *src = page_folio(page);
+ int rc = MIGRATEPAGE_SUCCESS;
+ struct page *newpage = NULL;
+
+ if (!thp_migration_supported() && PageTransHuge(page))
+ return -ENOSYS;
+
+ if (page_count(page) == 1) {
+ /* Page was freed from under us. So we are done. */
+ ClearPageActive(page);
+ ClearPageUnevictable(page);
+ /* free_pages_prepare() will clear PG_isolated. */
+ goto out;
+ }
+
+ newpage = get_new_page(page, private);
+ if (!newpage)
+ return -ENOMEM;
+ dst = page_folio(newpage);
+
+ newpage->private = 0;
+ rc = __unmap_and_move(src, dst, force, mode);
+ if (rc == MIGRATEPAGE_SUCCESS)
+ set_page_owner_migrate_reason(newpage, reason);
+
+out:
+ if (rc != -EAGAIN) {
+ /*
+ * A page that has been migrated has all references
+ * removed and will be freed. A page that has not been
+ * migrated will have kept its references and be restored.
+ */
+ list_del(&page->lru);
+ }
+
+ /*
+ * If migration is successful, releases reference grabbed during
+ * isolation. Otherwise, restore the page to right list unless
+ * we want to retry.
+ */
+ if (rc == MIGRATEPAGE_SUCCESS) {
+ /*
+ * Compaction can migrate also non-LRU pages which are
+ * not accounted to NR_ISOLATED_*. They can be recognized
+ * as __PageMovable
+ */
+ if (likely(!__PageMovable(page)))
+ mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON +
+ page_is_file_lru(page), -thp_nr_pages(page));
+
+ if (reason != MR_MEMORY_FAILURE)
+ /*
+ * We release the page in page_handle_poison.
+ */
+ put_page(page);
+ } else {
+ if (rc != -EAGAIN)
+ list_add_tail(&page->lru, ret);
+
+ if (put_new_page)
+ put_new_page(newpage, private);
+ else
+ put_page(newpage);
+ }
+
+ return rc;
+}
+
+/*
+ * Counterpart of unmap_and_move_page() for hugepage migration.
+ *
+ * This function doesn't wait the completion of hugepage I/O
+ * because there is no race between I/O and migration for hugepage.
+ * Note that currently hugepage I/O occurs only in direct I/O
+ * where no lock is held and PG_writeback is irrelevant,
+ * and writeback status of all subpages are counted in the reference
+ * count of the head page (i.e. if all subpages of a 2MB hugepage are
+ * under direct I/O, the reference of the head page is 512 and a bit more.)
+ * This means that when we try to migrate hugepage whose subpages are
+ * doing direct I/O, some references remain after try_to_unmap() and
+ * hugepage migration fails without data corruption.
+ *
+ * There is also no race when direct I/O is issued on the page under migration,
+ * because then pte is replaced with migration swap entry and direct I/O code
+ * will wait in the page fault for migration to complete.
+ */
+static int unmap_and_move_huge_page(new_page_t get_new_page,
+ free_page_t put_new_page, unsigned long private,
+ struct page *hpage, int force,
+ enum migrate_mode mode, int reason,
+ struct list_head *ret)
+{
+ struct folio *dst, *src = page_folio(hpage);
+ int rc = -EAGAIN;
+ int page_was_mapped = 0;
+ struct page *new_hpage;
+ struct anon_vma *anon_vma = NULL;
+ struct address_space *mapping = NULL;
+
+ /*
+ * Migratability of hugepages depends on architectures and their size.
+ * This check is necessary because some callers of hugepage migration
+ * like soft offline and memory hotremove don't walk through page
+ * tables or check whether the hugepage is pmd-based or not before
+ * kicking migration.
+ */
+ if (!hugepage_migration_supported(page_hstate(hpage)))
+ return -ENOSYS;
+
+ if (folio_ref_count(src) == 1) {
+ /* page was freed from under us. So we are done. */
+ putback_active_hugepage(hpage);
+ return MIGRATEPAGE_SUCCESS;
+ }
+
+ new_hpage = get_new_page(hpage, private);
+ if (!new_hpage)
+ return -ENOMEM;
+ dst = page_folio(new_hpage);
+
+ if (!folio_trylock(src)) {
+ if (!force)
+ goto out;
+ switch (mode) {
+ case MIGRATE_SYNC:
+ case MIGRATE_SYNC_NO_COPY:
+ break;
+ default:
+ goto out;
+ }
+ folio_lock(src);
+ }
+
+ /*
+ * Check for pages which are in the process of being freed. Without
+ * folio_mapping() set, hugetlbfs specific move page routine will not
+ * be called and we could leak usage counts for subpools.
+ */
+ if (hugetlb_page_subpool(hpage) && !folio_mapping(src)) {
+ rc = -EBUSY;
+ goto out_unlock;
+ }
+
+ if (folio_test_anon(src))
+ anon_vma = folio_get_anon_vma(src);
+
+ if (unlikely(!folio_trylock(dst)))
+ goto put_anon;
+
+ if (folio_mapped(src)) {
+ enum ttu_flags ttu = 0;
+
+ if (!folio_test_anon(src)) {
+ /*
+ * In shared mappings, try_to_unmap could potentially
+ * call huge_pmd_unshare. Because of this, take
+ * semaphore in write mode here and set TTU_RMAP_LOCKED
+ * to let lower levels know we have taken the lock.
+ */
+ mapping = hugetlb_page_mapping_lock_write(hpage);
+ if (unlikely(!mapping))
+ goto unlock_put_anon;
+
+ ttu = TTU_RMAP_LOCKED;
+ }
+
+ try_to_migrate(src, ttu);
+ page_was_mapped = 1;
+
+ if (ttu & TTU_RMAP_LOCKED)
+ i_mmap_unlock_write(mapping);
+ }
+
+ if (!folio_mapped(src))
+ rc = move_to_new_folio(dst, src, mode);
+
+ if (page_was_mapped)
+ remove_migration_ptes(src,
+ rc == MIGRATEPAGE_SUCCESS ? dst : src, false);
+
+unlock_put_anon:
+ folio_unlock(dst);
+
+put_anon:
+ if (anon_vma)
+ put_anon_vma(anon_vma);
+
+ if (rc == MIGRATEPAGE_SUCCESS) {
+ move_hugetlb_state(hpage, new_hpage, reason);
+ put_new_page = NULL;
+ }
+
+out_unlock:
+ folio_unlock(src);
+out:
+ if (rc == MIGRATEPAGE_SUCCESS)
+ putback_active_hugepage(hpage);
+ else if (rc != -EAGAIN)
+ list_move_tail(&src->lru, ret);
+
+ /*
+ * If migration was not successful and there's a freeing callback, use
+ * it. Otherwise, put_page() will drop the reference grabbed during
+ * isolation.
+ */
+ if (put_new_page)
+ put_new_page(new_hpage, private);
+ else
+ putback_active_hugepage(new_hpage);
+
+ return rc;
+}
+
+static inline int try_split_thp(struct page *page, struct list_head *split_pages)
+{
+ int rc;
+
+ lock_page(page);
+ rc = split_huge_page_to_list(page, split_pages);
+ unlock_page(page);
+ if (!rc)
+ list_move_tail(&page->lru, split_pages);
+
+ return rc;
+}
+
+/*
+ * migrate_pages - migrate the pages specified in a list, to the free pages
+ * supplied as the target for the page migration
+ *
+ * @from: The list of pages to be migrated.
+ * @get_new_page: The function used to allocate free pages to be used
+ * as the target of the page migration.
+ * @put_new_page: The function used to free target pages if migration
+ * fails, or NULL if no special handling is necessary.
+ * @private: Private data to be passed on to get_new_page()
+ * @mode: The migration mode that specifies the constraints for
+ * page migration, if any.
+ * @reason: The reason for page migration.
+ * @ret_succeeded: Set to the number of normal pages migrated successfully if
+ * the caller passes a non-NULL pointer.
+ *
+ * The function returns after 10 attempts or if no pages are movable any more
+ * because the list has become empty or no retryable pages exist any more.
+ * It is caller's responsibility to call putback_movable_pages() to return pages
+ * to the LRU or free list only if ret != 0.
+ *
+ * Returns the number of {normal page, THP, hugetlb} that were not migrated, or
+ * an error code. The number of THP splits will be considered as the number of
+ * non-migrated THP, no matter how many subpages of the THP are migrated successfully.
+ */
+int migrate_pages(struct list_head *from, new_page_t get_new_page,
+ free_page_t put_new_page, unsigned long private,
+ enum migrate_mode mode, int reason, unsigned int *ret_succeeded)
+{
+ int retry = 1;
+ int thp_retry = 1;
+ int nr_failed = 0;
+ int nr_failed_pages = 0;
+ int nr_retry_pages = 0;
+ int nr_succeeded = 0;
+ int nr_thp_succeeded = 0;
+ int nr_thp_failed = 0;
+ int nr_thp_split = 0;
+ int pass = 0;
+ bool is_thp = false;
+ struct page *page;
+ struct page *page2;
+ int rc, nr_subpages;
+ LIST_HEAD(ret_pages);
+ LIST_HEAD(thp_split_pages);
+ bool nosplit = (reason == MR_NUMA_MISPLACED);
+ bool no_subpage_counting = false;
+
+ trace_mm_migrate_pages_start(mode, reason);
+
+thp_subpage_migration:
+ for (pass = 0; pass < 10 && (retry || thp_retry); pass++) {
+ retry = 0;
+ thp_retry = 0;
+ nr_retry_pages = 0;
+
+ list_for_each_entry_safe(page, page2, from, lru) {
+ /*
+ * THP statistics is based on the source huge page.
+ * Capture required information that might get lost
+ * during migration.
+ */
+ is_thp = PageTransHuge(page) && !PageHuge(page);
+ nr_subpages = compound_nr(page);
+ cond_resched();
+
+ if (PageHuge(page))
+ rc = unmap_and_move_huge_page(get_new_page,
+ put_new_page, private, page,
+ pass > 2, mode, reason,
+ &ret_pages);
+ else
+ rc = unmap_and_move(get_new_page, put_new_page,
+ private, page, pass > 2, mode,
+ reason, &ret_pages);
+ /*
+ * The rules are:
+ * Success: non hugetlb page will be freed, hugetlb
+ * page will be put back
+ * -EAGAIN: stay on the from list
+ * -ENOMEM: stay on the from list
+ * -ENOSYS: stay on the from list
+ * Other errno: put on ret_pages list then splice to
+ * from list
+ */
+ switch(rc) {
+ /*
+ * THP migration might be unsupported or the
+ * allocation could've failed so we should
+ * retry on the same page with the THP split
+ * to base pages.
+ *
+ * Sub-pages are put in thp_split_pages, and
+ * we will migrate them after the rest of the
+ * list is processed.
+ */
+ case -ENOSYS:
+ /* THP migration is unsupported */
+ if (is_thp) {
+ nr_thp_failed++;
+ if (!try_split_thp(page, &thp_split_pages)) {
+ nr_thp_split++;
+ break;
+ }
+ /* Hugetlb migration is unsupported */
+ } else if (!no_subpage_counting) {
+ nr_failed++;
+ }
+
+ nr_failed_pages += nr_subpages;
+ list_move_tail(&page->lru, &ret_pages);
+ break;
+ case -ENOMEM:
+ /*
+ * When memory is low, don't bother to try to migrate
+ * other pages, just exit.
+ */
+ if (is_thp) {
+ nr_thp_failed++;
+ /* THP NUMA faulting doesn't split THP to retry. */
+ if (!nosplit && !try_split_thp(page, &thp_split_pages)) {
+ nr_thp_split++;
+ break;
+ }
+ } else if (!no_subpage_counting) {
+ nr_failed++;
+ }
+
+ nr_failed_pages += nr_subpages + nr_retry_pages;
+ /*
+ * There might be some subpages of fail-to-migrate THPs
+ * left in thp_split_pages list. Move them back to migration
+ * list so that they could be put back to the right list by
+ * the caller otherwise the page refcnt will be leaked.
+ */
+ list_splice_init(&thp_split_pages, from);
+ /* nr_failed isn't updated for not used */
+ nr_thp_failed += thp_retry;
+ goto out;
+ case -EAGAIN:
+ if (is_thp)
+ thp_retry++;
+ else if (!no_subpage_counting)
+ retry++;
+ nr_retry_pages += nr_subpages;
+ break;
+ case MIGRATEPAGE_SUCCESS:
+ nr_succeeded += nr_subpages;
+ if (is_thp)
+ nr_thp_succeeded++;
+ break;
+ default:
+ /*
+ * Permanent failure (-EBUSY, etc.):
+ * unlike -EAGAIN case, the failed page is
+ * removed from migration page list and not
+ * retried in the next outer loop.
+ */
+ if (is_thp)
+ nr_thp_failed++;
+ else if (!no_subpage_counting)
+ nr_failed++;
+
+ nr_failed_pages += nr_subpages;
+ break;
+ }
+ }
+ }
+ nr_failed += retry;
+ nr_thp_failed += thp_retry;
+ nr_failed_pages += nr_retry_pages;
+ /*
+ * Try to migrate subpages of fail-to-migrate THPs, no nr_failed
+ * counting in this round, since all subpages of a THP is counted
+ * as 1 failure in the first round.
+ */
+ if (!list_empty(&thp_split_pages)) {
+ /*
+ * Move non-migrated pages (after 10 retries) to ret_pages
+ * to avoid migrating them again.
+ */
+ list_splice_init(from, &ret_pages);
+ list_splice_init(&thp_split_pages, from);
+ no_subpage_counting = true;
+ retry = 1;
+ goto thp_subpage_migration;
+ }
+
+ rc = nr_failed + nr_thp_failed;
+out:
+ /*
+ * Put the permanent failure page back to migration list, they
+ * will be put back to the right list by the caller.
+ */
+ list_splice(&ret_pages, from);
+
+ /*
+ * Return 0 in case all subpages of fail-to-migrate THPs are
+ * migrated successfully.
+ */
+ if (list_empty(from))
+ rc = 0;
+
+ count_vm_events(PGMIGRATE_SUCCESS, nr_succeeded);
+ count_vm_events(PGMIGRATE_FAIL, nr_failed_pages);
+ count_vm_events(THP_MIGRATION_SUCCESS, nr_thp_succeeded);
+ count_vm_events(THP_MIGRATION_FAIL, nr_thp_failed);
+ count_vm_events(THP_MIGRATION_SPLIT, nr_thp_split);
+ trace_mm_migrate_pages(nr_succeeded, nr_failed_pages, nr_thp_succeeded,
+ nr_thp_failed, nr_thp_split, mode, reason);
+
+ if (ret_succeeded)
+ *ret_succeeded = nr_succeeded;
+
+ return rc;
+}
+
+struct page *alloc_migration_target(struct page *page, unsigned long private)
+{
+ struct folio *folio = page_folio(page);
+ struct migration_target_control *mtc;
+ gfp_t gfp_mask;
+ unsigned int order = 0;
+ struct folio *new_folio = NULL;
+ int nid;
+ int zidx;
+
+ mtc = (struct migration_target_control *)private;
+ gfp_mask = mtc->gfp_mask;
+ nid = mtc->nid;
+ if (nid == NUMA_NO_NODE)
+ nid = folio_nid(folio);
+
+ if (folio_test_hugetlb(folio)) {
+ struct hstate *h = page_hstate(&folio->page);
+
+ gfp_mask = htlb_modify_alloc_mask(h, gfp_mask);
+ return alloc_huge_page_nodemask(h, nid, mtc->nmask, gfp_mask);
+ }
+
+ if (folio_test_large(folio)) {
+ /*
+ * clear __GFP_RECLAIM to make the migration callback
+ * consistent with regular THP allocations.
+ */
+ gfp_mask &= ~__GFP_RECLAIM;
+ gfp_mask |= GFP_TRANSHUGE;
+ order = folio_order(folio);
+ }
+ zidx = zone_idx(folio_zone(folio));
+ if (is_highmem_idx(zidx) || zidx == ZONE_MOVABLE)
+ gfp_mask |= __GFP_HIGHMEM;
+
+ new_folio = __folio_alloc(gfp_mask, order, nid, mtc->nmask);
+
+ return &new_folio->page;
+}
+
+#ifdef CONFIG_NUMA
+
+static int store_status(int __user *status, int start, int value, int nr)
+{
+ while (nr-- > 0) {
+ if (put_user(value, status + start))
+ return -EFAULT;
+ start++;
+ }
+
+ return 0;
+}
+
+static int do_move_pages_to_node(struct mm_struct *mm,
+ struct list_head *pagelist, int node)
+{
+ int err;
+ struct migration_target_control mtc = {
+ .nid = node,
+ .gfp_mask = GFP_HIGHUSER_MOVABLE | __GFP_THISNODE,
+ };
+
+ err = migrate_pages(pagelist, alloc_migration_target, NULL,
+ (unsigned long)&mtc, MIGRATE_SYNC, MR_SYSCALL, NULL);
+ if (err)
+ putback_movable_pages(pagelist);
+ return err;
+}
+
+/*
+ * Resolves the given address to a struct page, isolates it from the LRU and
+ * puts it to the given pagelist.
+ * Returns:
+ * errno - if the page cannot be found/isolated
+ * 0 - when it doesn't have to be migrated because it is already on the
+ * target node
+ * 1 - when it has been queued
+ */
+static int add_page_for_migration(struct mm_struct *mm, unsigned long addr,
+ int node, struct list_head *pagelist, bool migrate_all)
+{
+ struct vm_area_struct *vma;
+ struct page *page;
+ int err;
+
+ mmap_read_lock(mm);
+ err = -EFAULT;
+ vma = vma_lookup(mm, addr);
+ if (!vma || !vma_migratable(vma))
+ goto out;
+
+ /* FOLL_DUMP to ignore special (like zero) pages */
+ page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP);
+
+ err = PTR_ERR(page);
+ if (IS_ERR(page))
+ goto out;
+
+ err = -ENOENT;
+ if (!page)
+ goto out;
+
+ if (is_zone_device_page(page))
+ goto out_putpage;
+
+ err = 0;
+ if (page_to_nid(page) == node)
+ goto out_putpage;
+
+ err = -EACCES;
+ if (page_mapcount(page) > 1 && !migrate_all)
+ goto out_putpage;
+
+ if (PageHuge(page)) {
+ if (PageHead(page)) {
+ err = isolate_hugetlb(page, pagelist);
+ if (!err)
+ err = 1;
+ }
+ } else {
+ struct page *head;
+
+ head = compound_head(page);
+ err = isolate_lru_page(head);
+ if (err)
+ goto out_putpage;
+
+ err = 1;
+ list_add_tail(&head->lru, pagelist);
+ mod_node_page_state(page_pgdat(head),
+ NR_ISOLATED_ANON + page_is_file_lru(head),
+ thp_nr_pages(head));
+ }
+out_putpage:
+ /*
+ * Either remove the duplicate refcount from
+ * isolate_lru_page() or drop the page ref if it was
+ * not isolated.
+ */
+ put_page(page);
+out:
+ mmap_read_unlock(mm);
+ return err;
+}
+
+static int move_pages_and_store_status(struct mm_struct *mm, int node,
+ struct list_head *pagelist, int __user *status,
+ int start, int i, unsigned long nr_pages)
+{
+ int err;
+
+ if (list_empty(pagelist))
+ return 0;
+
+ err = do_move_pages_to_node(mm, pagelist, node);
+ if (err) {
+ /*
+ * Positive err means the number of failed
+ * pages to migrate. Since we are going to
+ * abort and return the number of non-migrated
+ * pages, so need to include the rest of the
+ * nr_pages that have not been attempted as
+ * well.
+ */
+ if (err > 0)
+ err += nr_pages - i;
+ return err;
+ }
+ return store_status(status, start, node, i - start);
+}
+
+/*
+ * Migrate an array of page address onto an array of nodes and fill
+ * the corresponding array of status.
+ */
+static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
+ unsigned long nr_pages,
+ const void __user * __user *pages,
+ const int __user *nodes,
+ int __user *status, int flags)
+{
+ compat_uptr_t __user *compat_pages = (void __user *)pages;
+ int current_node = NUMA_NO_NODE;
+ LIST_HEAD(pagelist);
+ int start, i;
+ int err = 0, err1;
+
+ lru_cache_disable();
+
+ for (i = start = 0; i < nr_pages; i++) {
+ const void __user *p;
+ unsigned long addr;
+ int node;
+
+ err = -EFAULT;
+ if (in_compat_syscall()) {
+ compat_uptr_t cp;
+
+ if (get_user(cp, compat_pages + i))
+ goto out_flush;
+
+ p = compat_ptr(cp);
+ } else {
+ if (get_user(p, pages + i))
+ goto out_flush;
+ }
+ if (get_user(node, nodes + i))
+ goto out_flush;
+ addr = (unsigned long)untagged_addr(p);
+
+ err = -ENODEV;
+ if (node < 0 || node >= MAX_NUMNODES)
+ goto out_flush;
+ if (!node_state(node, N_MEMORY))
+ goto out_flush;
+
+ err = -EACCES;
+ if (!node_isset(node, task_nodes))
+ goto out_flush;
+
+ if (current_node == NUMA_NO_NODE) {
+ current_node = node;
+ start = i;
+ } else if (node != current_node) {
+ err = move_pages_and_store_status(mm, current_node,
+ &pagelist, status, start, i, nr_pages);
+ if (err)
+ goto out;
+ start = i;
+ current_node = node;
+ }
+
+ /*
+ * Errors in the page lookup or isolation are not fatal and we simply
+ * report them via status
+ */
+ err = add_page_for_migration(mm, addr, current_node,
+ &pagelist, flags & MPOL_MF_MOVE_ALL);
+
+ if (err > 0) {
+ /* The page is successfully queued for migration */
+ continue;
+ }
+
+ /*
+ * The move_pages() man page does not have an -EEXIST choice, so
+ * use -EFAULT instead.
+ */
+ if (err == -EEXIST)
+ err = -EFAULT;
+
+ /*
+ * If the page is already on the target node (!err), store the
+ * node, otherwise, store the err.
+ */
+ err = store_status(status, i, err ? : current_node, 1);
+ if (err)
+ goto out_flush;
+
+ err = move_pages_and_store_status(mm, current_node, &pagelist,
+ status, start, i, nr_pages);
+ if (err) {
+ /* We have accounted for page i */
+ if (err > 0)
+ err--;
+ goto out;
+ }
+ current_node = NUMA_NO_NODE;
+ }
+out_flush:
+ /* Make sure we do not overwrite the existing error */
+ err1 = move_pages_and_store_status(mm, current_node, &pagelist,
+ status, start, i, nr_pages);
+ if (err >= 0)
+ err = err1;
+out:
+ lru_cache_enable();
+ return err;
+}
+
+/*
+ * Determine the nodes of an array of pages and store it in an array of status.
+ */
+static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages,
+ const void __user **pages, int *status)
+{
+ unsigned long i;
+
+ mmap_read_lock(mm);
+
+ for (i = 0; i < nr_pages; i++) {
+ unsigned long addr = (unsigned long)(*pages);
+ unsigned int foll_flags = FOLL_DUMP;
+ struct vm_area_struct *vma;
+ struct page *page;
+ int err = -EFAULT;
+
+ vma = vma_lookup(mm, addr);
+ if (!vma)
+ goto set_status;
+
+ /* Not all huge page follow APIs support 'FOLL_GET' */
+ if (!is_vm_hugetlb_page(vma))
+ foll_flags |= FOLL_GET;
+
+ /* FOLL_DUMP to ignore special (like zero) pages */
+ page = follow_page(vma, addr, foll_flags);
+
+ err = PTR_ERR(page);
+ if (IS_ERR(page))
+ goto set_status;
+
+ err = -ENOENT;
+ if (!page)
+ goto set_status;
+
+ if (!is_zone_device_page(page))
+ err = page_to_nid(page);
+
+ if (foll_flags & FOLL_GET)
+ put_page(page);
+set_status:
+ *status = err;
+
+ pages++;
+ status++;
+ }
+
+ mmap_read_unlock(mm);
+}
+
+static int get_compat_pages_array(const void __user *chunk_pages[],
+ const void __user * __user *pages,
+ unsigned long chunk_nr)
+{
+ compat_uptr_t __user *pages32 = (compat_uptr_t __user *)pages;
+ compat_uptr_t p;
+ int i;
+
+ for (i = 0; i < chunk_nr; i++) {
+ if (get_user(p, pages32 + i))
+ return -EFAULT;
+ chunk_pages[i] = compat_ptr(p);
+ }
+
+ return 0;
+}
+
+/*
+ * Determine the nodes of a user array of pages and store it in
+ * a user array of status.
+ */
+static int do_pages_stat(struct mm_struct *mm, unsigned long nr_pages,
+ const void __user * __user *pages,
+ int __user *status)
+{
+#define DO_PAGES_STAT_CHUNK_NR 16UL
+ const void __user *chunk_pages[DO_PAGES_STAT_CHUNK_NR];
+ int chunk_status[DO_PAGES_STAT_CHUNK_NR];
+
+ while (nr_pages) {
+ unsigned long chunk_nr = min(nr_pages, DO_PAGES_STAT_CHUNK_NR);
+
+ if (in_compat_syscall()) {
+ if (get_compat_pages_array(chunk_pages, pages,
+ chunk_nr))
+ break;
+ } else {
+ if (copy_from_user(chunk_pages, pages,
+ chunk_nr * sizeof(*chunk_pages)))
+ break;
+ }
+
+ do_pages_stat_array(mm, chunk_nr, chunk_pages, chunk_status);
+
+ if (copy_to_user(status, chunk_status, chunk_nr * sizeof(*status)))
+ break;
+
+ pages += chunk_nr;
+ status += chunk_nr;
+ nr_pages -= chunk_nr;
+ }
+ return nr_pages ? -EFAULT : 0;
+}
+
+static struct mm_struct *find_mm_struct(pid_t pid, nodemask_t *mem_nodes)
+{
+ struct task_struct *task;
+ struct mm_struct *mm;
+
+ /*
+ * There is no need to check if current process has the right to modify
+ * the specified process when they are same.
+ */
+ if (!pid) {
+ mmget(current->mm);
+ *mem_nodes = cpuset_mems_allowed(current);
+ return current->mm;
+ }
+
+ /* Find the mm_struct */
+ rcu_read_lock();
+ task = find_task_by_vpid(pid);
+ if (!task) {
+ rcu_read_unlock();
+ return ERR_PTR(-ESRCH);
+ }
+ get_task_struct(task);
+
+ /*
+ * Check if this process has the right to modify the specified
+ * process. Use the regular "ptrace_may_access()" checks.
+ */
+ if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) {
+ rcu_read_unlock();
+ mm = ERR_PTR(-EPERM);
+ goto out;
+ }
+ rcu_read_unlock();
+
+ mm = ERR_PTR(security_task_movememory(task));
+ if (IS_ERR(mm))
+ goto out;
+ *mem_nodes = cpuset_mems_allowed(task);
+ mm = get_task_mm(task);
+out:
+ put_task_struct(task);
+ if (!mm)
+ mm = ERR_PTR(-EINVAL);
+ return mm;
+}
+
+/*
+ * Move a list of pages in the address space of the currently executing
+ * process.
+ */
+static int kernel_move_pages(pid_t pid, unsigned long nr_pages,
+ const void __user * __user *pages,
+ const int __user *nodes,
+ int __user *status, int flags)
+{
+ struct mm_struct *mm;
+ int err;
+ nodemask_t task_nodes;
+
+ /* Check flags */
+ if (flags & ~(MPOL_MF_MOVE|MPOL_MF_MOVE_ALL))
+ return -EINVAL;
+
+ if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
+ return -EPERM;
+
+ mm = find_mm_struct(pid, &task_nodes);
+ if (IS_ERR(mm))
+ return PTR_ERR(mm);
+
+ if (nodes)
+ err = do_pages_move(mm, task_nodes, nr_pages, pages,
+ nodes, status, flags);
+ else
+ err = do_pages_stat(mm, nr_pages, pages, status);
+
+ mmput(mm);
+ return err;
+}
+
+SYSCALL_DEFINE6(move_pages, pid_t, pid, unsigned long, nr_pages,
+ const void __user * __user *, pages,
+ const int __user *, nodes,
+ int __user *, status, int, flags)
+{
+ return kernel_move_pages(pid, nr_pages, pages, nodes, status, flags);
+}
+
+#ifdef CONFIG_NUMA_BALANCING
+/*
+ * Returns true if this is a safe migration target node for misplaced NUMA
+ * pages. Currently it only checks the watermarks which is crude.
+ */
+static bool migrate_balanced_pgdat(struct pglist_data *pgdat,
+ unsigned long nr_migrate_pages)
+{
+ int z;
+
+ for (z = pgdat->nr_zones - 1; z >= 0; z--) {
+ struct zone *zone = pgdat->node_zones + z;
+
+ if (!managed_zone(zone))
+ continue;
+
+ /* Avoid waking kswapd by allocating pages_to_migrate pages. */
+ if (!zone_watermark_ok(zone, 0,
+ high_wmark_pages(zone) +
+ nr_migrate_pages,
+ ZONE_MOVABLE, 0))
+ continue;
+ return true;
+ }
+ return false;
+}
+
+static struct page *alloc_misplaced_dst_page(struct page *page,
+ unsigned long data)
+{
+ int nid = (int) data;
+ int order = compound_order(page);
+ gfp_t gfp = __GFP_THISNODE;
+ struct folio *new;
+
+ if (order > 0)
+ gfp |= GFP_TRANSHUGE_LIGHT;
+ else {
+ gfp |= GFP_HIGHUSER_MOVABLE | __GFP_NOMEMALLOC | __GFP_NORETRY |
+ __GFP_NOWARN;
+ gfp &= ~__GFP_RECLAIM;
+ }
+ new = __folio_alloc_node(gfp, order, nid);
+
+ return &new->page;
+}
+
+static int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page)
+{
+ int nr_pages = thp_nr_pages(page);
+ int order = compound_order(page);
+
+ VM_BUG_ON_PAGE(order && !PageTransHuge(page), page);
+
+ /* Do not migrate THP mapped by multiple processes */
+ if (PageTransHuge(page) && total_mapcount(page) > 1)
+ return 0;
+
+ /* Avoid migrating to a node that is nearly full */
+ if (!migrate_balanced_pgdat(pgdat, nr_pages)) {
+ int z;
+
+ if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING))
+ return 0;
+ for (z = pgdat->nr_zones - 1; z >= 0; z--) {
+ if (managed_zone(pgdat->node_zones + z))
+ break;
+ }
+ wakeup_kswapd(pgdat->node_zones + z, 0, order, ZONE_MOVABLE);
+ return 0;
+ }
+
+ if (isolate_lru_page(page))
+ return 0;
+
+ mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON + page_is_file_lru(page),
+ nr_pages);
+
+ /*
+ * Isolating the page has taken another reference, so the
+ * caller's reference can be safely dropped without the page
+ * disappearing underneath us during migration.
+ */
+ put_page(page);
+ return 1;
+}
+
+/*
+ * Attempt to migrate a misplaced page to the specified destination
+ * node. Caller is expected to have an elevated reference count on
+ * the page that will be dropped by this function before returning.
+ */
+int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma,
+ int node)
+{
+ pg_data_t *pgdat = NODE_DATA(node);
+ int isolated;
+ int nr_remaining;
+ unsigned int nr_succeeded;
+ LIST_HEAD(migratepages);
+ int nr_pages = thp_nr_pages(page);
+
+ /*
+ * Don't migrate file pages that are mapped in multiple processes
+ * with execute permissions as they are probably shared libraries.
+ */
+ if (page_mapcount(page) != 1 && page_is_file_lru(page) &&
+ (vma->vm_flags & VM_EXEC))
+ goto out;
+
+ /*
+ * Also do not migrate dirty pages as not all filesystems can move
+ * dirty pages in MIGRATE_ASYNC mode which is a waste of cycles.
+ */
+ if (page_is_file_lru(page) && PageDirty(page))
+ goto out;
+
+ isolated = numamigrate_isolate_page(pgdat, page);
+ if (!isolated)
+ goto out;
+
+ list_add(&page->lru, &migratepages);
+ nr_remaining = migrate_pages(&migratepages, alloc_misplaced_dst_page,
+ NULL, node, MIGRATE_ASYNC,
+ MR_NUMA_MISPLACED, &nr_succeeded);
+ if (nr_remaining) {
+ if (!list_empty(&migratepages)) {
+ list_del(&page->lru);
+ mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON +
+ page_is_file_lru(page), -nr_pages);
+ putback_lru_page(page);
+ }
+ isolated = 0;
+ }
+ if (nr_succeeded) {
+ count_vm_numa_events(NUMA_PAGE_MIGRATE, nr_succeeded);
+ if (!node_is_toptier(page_to_nid(page)) && node_is_toptier(node))
+ mod_node_page_state(pgdat, PGPROMOTE_SUCCESS,
+ nr_succeeded);
+ }
+ BUG_ON(!list_empty(&migratepages));
+ return isolated;
+
+out:
+ put_page(page);
+ return 0;
+}
+#endif /* CONFIG_NUMA_BALANCING */
+#endif /* CONFIG_NUMA */