kernel/linux.git/include/linux/page-flags.h, branch v6.6.132

highmem: add folio_test_partial_kmap()

2025-06-04T12:42:21+00:00

commit 97dfbbd135cb5e4426f37ca53a8fa87eaaa4e376 upstream. In commit c749d9b7ebbc ("iov_iter: fix copy_page_from_iter_atomic() if KMAP_LOCAL_FORCE_MAP"), Hugh correctly noted that if KMAP_LOCAL_FORCE_MAP is enabled, we must limit ourselves to PAGE_SIZE bytes per call to kmap_local(). The same problem exists in memcpy_from_folio(), memcpy_to_folio(), folio_zero_tail(), folio_fill_tail() and memcpy_from_file_folio(), so add folio_test_partial_kmap() to do this more succinctly. Link: https://lkml.kernel.org/r/20250514170607.3000994-2-willy@infradead.org Fixes: 00cdf76012ab ("mm: add memcpy_from_file_folio()") Signed-off-by: Matthew Wilcox (Oracle) Cc: Al Viro Cc: Hugh Dickins Cc: Signed-off-by: Andrew Morton Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Greg Kroah-Hartman

mm: turn folio_test_hugetlb into a PageType

2024-05-02T14:32:47+00:00

commit d99e3140a4d33e26066183ff727d8f02f56bec64 upstream. The current folio_test_hugetlb() can be fooled by a concurrent folio split into returning true for a folio which has never belonged to hugetlbfs. This can't happen if the caller holds a refcount on it, but we have a few places (memory-failure, compaction, procfs) which do not and should not take a speculative reference. Since hugetlb pages do not use individual page mapcounts (they are always fully mapped and use the entire_mapcount field to record the number of mappings), the PageType field is available now that page_mapcount() ignores the value in this field. In compaction and with CONFIG_DEBUG_VM enabled, the current implementation can result in an oops, as reported by Luis. This happens since 9c5ccf2db04b ("mm: remove HUGETLB_PAGE_DTOR") effectively added some VM_BUG_ON() checks in the PageHuge() testing path. [willy@infradead.org: update vmcoreinfo] Link: https://lkml.kernel.org/r/ZgGZUvsdhaT1Va-T@casper.infradead.org Link: https://lkml.kernel.org/r/20240321142448.1645400-6-willy@infradead.org Fixes: 9c5ccf2db04b ("mm: remove HUGETLB_PAGE_DTOR") Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: David Hildenbrand Acked-by: Vlastimil Babka Reported-by: Luis Chamberlain Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218227 Cc: Miaohe Lin Cc: Muchun Song Cc: Oscar Salvador Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

mm: support page_mapcount() on page_has_type() pages

2024-05-02T14:32:43+00:00

commit fd1a745ce03e37945674c14833870a9af0882e2d upstream. Return 0 for pages which can't be mapped. This matches how page_mapped() works. It is more convenient for users to not have to filter out these pages. Link: https://lkml.kernel.org/r/20240321142448.1645400-5-willy@infradead.org Fixes: 9c5ccf2db04b ("mm: remove HUGETLB_PAGE_DTOR") Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: David Hildenbrand Acked-by: Vlastimil Babka Cc: Miaohe Lin Cc: Muchun Song Cc: Oscar Salvador Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

mm: create FOLIO_FLAG_FALSE and FOLIO_TYPE_OPS macros

2024-05-02T14:32:43+00:00

commit 12bbaae7635a56049779db3bef6e7140d9aa5f67 upstream. Following the separation of FOLIO_FLAGS from PAGEFLAGS, separate FOLIO_FLAG_FALSE from PAGEFLAG_FALSE and FOLIO_TYPE_OPS from PAGE_TYPE_OPS. Link: https://lkml.kernel.org/r/20240321142448.1645400-3-willy@infradead.org Fixes: 9c5ccf2db04b ("mm: remove HUGETLB_PAGE_DTOR") Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: David Hildenbrand Acked-by: Vlastimil Babka Cc: Miaohe Lin Cc: Muchun Song Cc: Oscar Salvador Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

mm: remove folio_test_transhuge()

2023-08-21T21:28:45+00:00

This function is misleading; people think it means "Is this a THP", when all it actually does is check whether this is a large folio. Remove it; the one remaining user should have been checking to see whether the folio is PMD sized or not. Link: https://lkml.kernel.org/r/20230816151201.3655946-12-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Cc: David Hildenbrand Cc: Jens Axboe Cc: Sidhartha Kumar Cc: Yanteng Si Signed-off-by: Andrew Morton

mm: free up a word in the first tail page

2023-08-21T21:28:45+00:00

Store the folio order in the low byte of the flags word in the first tail page. This frees up the word that was being used to store the order and dtor bytes previously. Link: https://lkml.kernel.org/r/20230816151201.3655946-11-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Cc: David Hildenbrand Cc: Jens Axboe Cc: Sidhartha Kumar Cc: Yanteng Si Signed-off-by: Andrew Morton

mm: rearrange page flags

2023-08-21T21:28:44+00:00

Move PG_writeback into bottom byte so that it can use PG_waiters in a later patch. Move PG_head into bottom byte as well to match with where 'order' is moving next. PG_active and PG_workingset move into the second byte to make room for them. By putting PG_head in bit 6, we ensure that it is cleared by assigning the folio order to the bottom byte of the first tail page (since the order cannot be larger than 63). Link: https://lkml.kernel.org/r/20230816151201.3655946-10-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Cc: David Hildenbrand Cc: Jens Axboe Cc: Sidhartha Kumar Cc: Yanteng Si Signed-off-by: Andrew Morton

mm: add large_rmappable page flag

2023-08-21T21:28:44+00:00

Stored in the first tail page's flags, this flag replaces the destructor. That removes the last of the destructors, so remove all references to folio_dtor and compound_dtor. Link: https://lkml.kernel.org/r/20230816151201.3655946-9-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Cc: David Hildenbrand Cc: Jens Axboe Cc: Sidhartha Kumar Cc: Yanteng Si Signed-off-by: Andrew Morton

mm: remove HUGETLB_PAGE_DTOR

2023-08-21T21:28:44+00:00

We can use a bit in page[1].flags to indicate that this folio belongs to hugetlb instead of using a value in page[1].dtors. That lets folio_test_hugetlb() become an inline function like it should be. We can also get rid of NULL_COMPOUND_DTOR. Link: https://lkml.kernel.org/r/20230816151201.3655946-8-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Cc: David Hildenbrand Cc: Jens Axboe Cc: Sidhartha Kumar Cc: Yanteng Si Signed-off-by: Andrew Morton

mm: add PAGE_TYPE_OP folio functions

2023-08-21T20:37:51+00:00

Patch series "Split ptdesc from struct page", v9. The MM subsystem is trying to shrink struct page. This patchset introduces a memory descriptor for page table tracking - struct ptdesc. This patchset introduces ptdesc, splits ptdesc from struct page, and converts many callers of page table constructor/destructors to use ptdescs. Ptdesc is a foundation to further standardize page tables, and eventually allow for dynamic allocation of page tables independent of struct page. However, the use of pages for page table tracking is quite deeply ingrained and varied across archictectures, so there is still a lot of work to be done before that can happen. This patch (of 31): No folio equivalents for page type operations have been defined, so define them for later folio conversions. Also changes the Page##uname macros to take in const struct page* since we only read the memory here. Link: https://lkml.kernel.org/r/20230807230513.102486-1-vishal.moola@gmail.com Link: https://lkml.kernel.org/r/20230807230513.102486-2-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) Acked-by: Mike Rapoport (IBM) Cc: Arnd Bergmann Cc: Catalin Marinas Cc: Christophe Leroy Cc: Claudio Imbrenda Cc: Dave Hansen Cc: David Hildenbrand Cc: "David S. Miller" Cc: Dinh Nguyen Cc: Geert Uytterhoeven Cc: Huacai Chen Cc: Hugh Dickins Cc: Jonas Bonn Cc: Matthew Wilcox Cc: Paul Walmsley Cc: Richard Weinberger Cc: Thomas Bogendoerfer Cc: Yoshinori Sato Cc: Geert Uytterhoeven Cc: Guo Ren Cc: John Paul Adrian Glaubitz Cc: Palmer Dabbelt Signed-off-by: Andrew Morton