On 4 Feb 2022, at 14:58, Matthew Wilcox (Oracle) wrote: > Convert the callers to pass a folio and the try_to_migrate_one() > worker to use a folio throughout. Fixes an assumption that a > folio must be <= PMD size. > > Signed-off-by: Matthew Wilcox (Oracle) > --- > include/linux/rmap.h | 2 +- > mm/huge_memory.c | 4 ++-- > mm/migrate.c | 12 ++++++---- > mm/rmap.c | 57 +++++++++++++++++++++++--------------------- > 4 files changed, 41 insertions(+), 34 deletions(-) > > diff --git a/include/linux/rmap.h b/include/linux/rmap.h > index 66407434c3b5..502439f20d88 100644 > --- a/include/linux/rmap.h > +++ b/include/linux/rmap.h > @@ -192,7 +192,7 @@ static inline void page_dup_rmap(struct page *page, bool compound) > int folio_referenced(struct folio *, int is_locked, > struct mem_cgroup *memcg, unsigned long *vm_flags); > > -void try_to_migrate(struct page *page, enum ttu_flags flags); > +void try_to_migrate(struct folio *folio, enum ttu_flags flags); > void try_to_unmap(struct folio *, enum ttu_flags flags); > > int make_device_exclusive_range(struct mm_struct *mm, unsigned long start, > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 4ea22b7319fd..21676a4afd07 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -2294,8 +2294,8 @@ static void unmap_page(struct page *page) > * pages can simply be left unmapped, then faulted back on demand. > * If that is ever changed (perhaps for mlock), update remap_page(). > */ > - if (PageAnon(page)) > - try_to_migrate(page, ttu_flags); > + if (folio_test_anon(folio)) > + try_to_migrate(folio, ttu_flags); > else > try_to_unmap(folio, ttu_flags | TTU_IGNORE_MLOCK); > > diff --git a/mm/migrate.c b/mm/migrate.c > index 766dc67874a1..5dcdd43d983d 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -927,6 +927,7 @@ static int move_to_new_page(struct page *newpage, struct page *page, > static int __unmap_and_move(struct page *page, struct page *newpage, > int force, enum migrate_mode mode) > { > + struct folio *folio = page_folio(page); > int rc = -EAGAIN; > bool page_was_mapped = false; > struct anon_vma *anon_vma = NULL; > @@ -1030,7 +1031,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage, > /* Establish migration ptes */ > VM_BUG_ON_PAGE(PageAnon(page) && !PageKsm(page) && !anon_vma, > page); > - try_to_migrate(page, 0); > + try_to_migrate(folio, 0); > page_was_mapped = true; > } > > @@ -1173,6 +1174,7 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, > enum migrate_mode mode, int reason, > struct list_head *ret) > { > + struct folio *src = page_folio(hpage); > int rc = -EAGAIN; > int page_was_mapped = 0; > struct page *new_hpage; > @@ -1249,7 +1251,7 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, > ttu |= TTU_RMAP_LOCKED; > } > > - try_to_migrate(hpage, ttu); > + try_to_migrate(src, ttu); > page_was_mapped = 1; > > if (mapping_locked) > @@ -2449,6 +2451,7 @@ static void migrate_vma_unmap(struct migrate_vma *migrate) > > for (i = 0; i < npages; i++) { > struct page *page = migrate_pfn_to_page(migrate->src[i]); > + struct folio *folio; > > if (!page) > continue; > @@ -2472,8 +2475,9 @@ static void migrate_vma_unmap(struct migrate_vma *migrate) > put_page(page); > } > > - if (page_mapped(page)) > - try_to_migrate(page, 0); > + folio = page_folio(page); > + if (folio_mapped(folio)) > + try_to_migrate(folio, 0); > > if (page_mapped(page) || !migrate_vma_check_page(page)) { > if (!is_zone_device_page(page)) { > diff --git a/mm/rmap.c b/mm/rmap.c > index c598fd667948..4cfac67e328c 100644 > --- a/mm/rmap.c > +++ b/mm/rmap.c > @@ -1767,7 +1767,7 @@ static bool try_to_migrate_one(struct page *page, struct vm_area_struct *vma, > range.end = vma_address_end(&pvmw); > mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, > address, range.end); > - if (PageHuge(page)) { > + if (folio_test_hugetlb(folio)) { > /* > * If sharing is possible, start and end will be adjusted > * accordingly. > @@ -1781,21 +1781,24 @@ static bool try_to_migrate_one(struct page *page, struct vm_area_struct *vma, > #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION > /* PMD-mapped THP migration entry */ > if (!pvmw.pte) { > - VM_BUG_ON_PAGE(PageHuge(page) || > - !PageTransCompound(page), page); > + subpage = folio_page(folio, > + pmd_pfn(*pvmw.pmd) - folio_pfn(folio)); Here you removed the assumption that folio is always <= PMD, right? In the commit message, maybe the below is better? In THP migration code, fixes an assumption that a folio must be <= PMD size. > + VM_BUG_ON_FOLIO(folio_test_hugetlb(folio) || > + !folio_test_pmd_mappable(folio), folio); > > - set_pmd_migration_entry(&pvmw, page); > + set_pmd_migration_entry(&pvmw, subpage); > continue; > } > #endif > > /* Unexpected PMD-mapped THP? */ > - VM_BUG_ON_PAGE(!pvmw.pte, page); > + VM_BUG_ON_FOLIO(!pvmw.pte, folio); > > - subpage = page - page_to_pfn(page) + pte_pfn(*pvmw.pte); > + subpage = folio_page(folio, > + pte_pfn(*pvmw.pte) - folio_pfn(folio)); > address = pvmw.address; > > - if (PageHuge(page) && !PageAnon(page)) { > + if (folio_test_hugetlb(folio) && !folio_test_anon(folio)) { > /* > * To call huge_pmd_unshare, i_mmap_rwsem must be > * held in write mode. Caller needs to explicitly > @@ -1833,15 +1836,15 @@ static bool try_to_migrate_one(struct page *page, struct vm_area_struct *vma, > flush_cache_page(vma, address, pte_pfn(*pvmw.pte)); > pteval = ptep_clear_flush(vma, address, pvmw.pte); > > - /* Move the dirty bit to the page. Now the pte is gone. */ > + /* Set the dirty flag on the folio now the pte is gone. */ > if (pte_dirty(pteval)) > - set_page_dirty(page); > + folio_mark_dirty(folio); > > /* Update high watermark before we lower rss */ > update_hiwater_rss(mm); > > - if (is_zone_device_page(page)) { > - unsigned long pfn = page_to_pfn(page); > + if (folio_is_zone_device(folio)) { > + unsigned long pfn = folio_pfn(folio); > swp_entry_t entry; > pte_t swp_pte; > > @@ -1877,16 +1880,16 @@ static bool try_to_migrate_one(struct page *page, struct vm_area_struct *vma, > * changed when hugepage migrations to device private > * memory are supported. > */ > - subpage = page; > - } else if (PageHWPoison(page)) { > + subpage = &folio->page; > + } else if (PageHWPoison(subpage)) { > pteval = swp_entry_to_pte(make_hwpoison_entry(subpage)); > - if (PageHuge(page)) { > - hugetlb_count_sub(compound_nr(page), mm); > + if (folio_test_hugetlb(folio)) { > + hugetlb_count_sub(folio_nr_pages(folio), mm); > set_huge_swap_pte_at(mm, address, > pvmw.pte, pteval, > vma_mmu_pagesize(vma)); > } else { > - dec_mm_counter(mm, mm_counter(page)); > + dec_mm_counter(mm, mm_counter(&folio->page)); > set_pte_at(mm, address, pvmw.pte, pteval); > } > > @@ -1901,7 +1904,7 @@ static bool try_to_migrate_one(struct page *page, struct vm_area_struct *vma, > * migration) will not expect userfaults on already > * copied pages. > */ > - dec_mm_counter(mm, mm_counter(page)); > + dec_mm_counter(mm, mm_counter(&folio->page)); > /* We have to invalidate as we cleared the pte */ > mmu_notifier_invalidate_range(mm, address, > address + PAGE_SIZE); > @@ -1947,8 +1950,8 @@ static bool try_to_migrate_one(struct page *page, struct vm_area_struct *vma, > * > * See Documentation/vm/mmu_notifier.rst > */ > - page_remove_rmap(subpage, PageHuge(page)); > - put_page(page); > + page_remove_rmap(subpage, folio_test_hugetlb(folio)); > + folio_put(folio); > } > > mmu_notifier_invalidate_range_end(&range); > @@ -1958,13 +1961,13 @@ static bool try_to_migrate_one(struct page *page, struct vm_area_struct *vma, > > /** > * try_to_migrate - try to replace all page table mappings with swap entries > - * @page: the page to replace page table entries for > + * @folio: the folio to replace page table entries for > * @flags: action and flags > * > - * Tries to remove all the page table entries which are mapping this page and > - * replace them with special swap entries. Caller must hold the page lock. > + * Tries to remove all the page table entries which are mapping this folio and > + * replace them with special swap entries. Caller must hold the folio lock. > */ > -void try_to_migrate(struct page *page, enum ttu_flags flags) > +void try_to_migrate(struct folio *folio, enum ttu_flags flags) > { > struct rmap_walk_control rwc = { > .rmap_one = try_to_migrate_one, > @@ -1981,7 +1984,7 @@ void try_to_migrate(struct page *page, enum ttu_flags flags) > TTU_SYNC))) > return; > > - if (is_zone_device_page(page) && !is_device_private_page(page)) > + if (folio_is_zone_device(folio) && !folio_is_device_private(folio)) > return; > > /* > @@ -1992,13 +1995,13 @@ void try_to_migrate(struct page *page, enum ttu_flags flags) > * locking requirements of exec(), migration skips > * temporary VMAs until after exec() completes. > */ > - if (!PageKsm(page) && PageAnon(page)) > + if (!folio_test_ksm(folio) && folio_test_anon(folio)) > rwc.invalid_vma = invalid_migration_vma; > > if (flags & TTU_RMAP_LOCKED) > - rmap_walk_locked(page, &rwc); > + rmap_walk_locked(&folio->page, &rwc); > else > - rmap_walk(page, &rwc); > + rmap_walk(&folio->page, &rwc); > } > > /* > -- > 2.34.1 Otherwise, LGTM. Thanks. Reviewed-by: Zi Yan -- Best Regards, Yan, Zi