The quilt patch titled
Subject: mm: support page_mapcount() on page_has_type() pages
has been removed from the -mm tree. Its filename was
mm-support-page_mapcount-on-page_has_type-pages.patch
This patch was dropped because it was merged into the mm-hotfixes-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: mm: support page_mapcount() on page_has_type() pages
Date: Thu, 21 Mar 2024 14:24:42 +0000
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@xxxxxxxxxxxxx
Fixes: 9c5ccf2db04b ("mm: remove HUGETLB_PAGE_DTOR")
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/page.c | 7 ++-----
include/linux/mm.h | 8 +++++---
include/linux/page-flags.h | 4 ++--
3 files changed, 9 insertions(+), 10 deletions(-)
--- a/fs/proc/page.c~mm-support-page_mapcount-on-page_has_type-pages
+++ a/fs/proc/page.c
@@ -67,7 +67,7 @@ static ssize_t kpagecount_read(struct fi
*/
ppage = pfn_to_online_page(pfn);
- if (!ppage || PageSlab(ppage) || page_has_type(ppage))
+ if (!ppage)
pcount = 0;
else
pcount = page_mapcount(ppage);
@@ -124,11 +124,8 @@ u64 stable_page_flags(struct page *page)
/*
* pseudo flags for the well known (anonymous) memory mapped pages
- *
- * Note that page->_mapcount is overloaded in SLAB, so the
- * simple test in page_mapped() is not enough.
*/
- if (!PageSlab(page) && page_mapped(page))
+ if (page_mapped(page))
u |= 1 << KPF_MMAP;
if (PageAnon(page))
u |= 1 << KPF_ANON;
--- a/include/linux/mm.h~mm-support-page_mapcount-on-page_has_type-pages
+++ a/include/linux/mm.h
@@ -1223,14 +1223,16 @@ static inline void page_mapcount_reset(s
* a large folio, it includes the number of times this page is mapped
* as part of that folio.
*
- * The result is undefined for pages which cannot be mapped into userspace.
- * For example SLAB or special types of pages. See function page_has_type().
- * They use this field in struct page differently.
+ * Will report 0 for pages which cannot be mapped into userspace, eg
+ * slab, page tables and similar.
*/
static inline int page_mapcount(struct page *page)
{
int mapcount = atomic_read(&page->_mapcount) + 1;
+ /* Handle page_has_type() pages */
+ if (mapcount < 0)
+ mapcount = 0;
if (unlikely(PageCompound(page)))
mapcount += folio_entire_mapcount(page_folio(page));
--- a/include/linux/page-flags.h~mm-support-page_mapcount-on-page_has_type-pages
+++ a/include/linux/page-flags.h
@@ -971,12 +971,12 @@ static inline bool is_page_hwpoison(stru
* page_type may be used. Because it is initialised to -1, we invert the
* sense of the bit, so __SetPageFoo *clears* the bit used for PageFoo, and
* __ClearPageFoo *sets* the bit used for PageFoo. We reserve a few high and
- * low bits so that an underflow or overflow of page_mapcount() won't be
+ * low bits so that an underflow or overflow of _mapcount won't be
* mistaken for a page type value.
*/
#define PAGE_TYPE_BASE 0xf0000000
-/* Reserve 0x0000007f to catch underflows of page_mapcount */
+/* Reserve 0x0000007f to catch underflows of _mapcount */
#define PAGE_MAPCOUNT_RESERVE -128
#define PG_buddy 0x00000080
#define PG_offline 0x00000100
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
mm-always-initialise-folio-_deferred_list.patch
mm-remove-folio_prep_large_rmappable.patch
mm-remove-a-call-to-compound_head-from-is_page_hwpoison.patch
mm-free-up-pg_slab.patch
mm-free-up-pg_slab-fix.patch
mm-improve-dumping-of-mapcount-and-page_type.patch
hugetlb-remove-mention-of-destructors.patch
sh-remove-use-of-pg_arch_1-on-individual-pages.patch
xtensa-remove-uses-of-pg_arch_1-on-individual-pages.patch
mm-make-page_ext_get-take-a-const-argument.patch
mm-make-folio_test_idle-and-folio_test_young-take-a-const-argument.patch
mm-make-is_free_buddy_page-take-a-const-argument.patch
mm-make-page_mapped-take-a-const-argument.patch
mm-convert-arch_clear_hugepage_flags-to-take-a-folio.patch
mm-convert-arch_clear_hugepage_flags-to-take-a-folio-fix.patch
slub-remove-use-of-page-flags.patch
remove-references-to-page-flags-in-documentation.patch
proc-rewrite-stable_page_flags.patch
proc-rewrite-stable_page_flags-fix.patch
proc-rewrite-stable_page_flags-fix-2.patch
sparc-use-is_huge_zero_pmd.patch
mm-add-is_huge_zero_folio.patch
mm-add-pmd_folio.patch
mm-convert-migrate_vma_collect_pmd-to-use-a-folio.patch
mm-convert-huge_zero_page-to-huge_zero_folio.patch
mm-convert-do_huge_pmd_anonymous_page-to-huge_zero_folio.patch
dax-use-huge_zero_folio.patch
mm-rename-mm_put_huge_zero_page-to-mm_put_huge_zero_folio.patch
mm-use-rwsem-assertion-macros-for-mmap_lock.patch
filemap-remove-__set_page_dirty.patch
mm-correct-page_mapped_in_vma-for-large-folios.patch
mm-remove-vma_address.patch
mm-rename-vma_pgoff_address-back-to-vma_address.patch
khugepaged-inline-hpage_collapse_alloc_folio.patch
khugepaged-convert-alloc_charge_hpage-to-alloc_charge_folio.patch
khugepaged-remove-hpage-from-collapse_huge_page.patch
khugepaged-pass-a-folio-to-__collapse_huge_page_copy.patch
khugepaged-remove-hpage-from-collapse_file.patch
khugepaged-use-a-folio-throughout-collapse_file.patch
khugepaged-use-a-folio-throughout-collapse_file-fix.patch
khugepaged-use-a-folio-throughout-hpage_collapse_scan_file.patch
proc-convert-clear_refs_pte_range-to-use-a-folio.patch
proc-convert-smaps_account-to-use-a-folio.patch
mm-remove-page_idle-and-page_young-wrappers.patch
mm-generate-page_idle_flag-definitions.patch
proc-convert-gather_stats-to-use-a-folio.patch
proc-convert-smaps_page_accumulate-to-use-a-folio.patch
proc-pass-a-folio-to-smaps_page_accumulate.patch
proc-convert-smaps_pmd_entry-to-use-a-folio.patch
mm-remove-struct-page-from-get_shadow_from_swap_cache.patch
hugetlb-convert-alloc_buddy_hugetlb_folio-to-use-a-folio.patch
mm-convert-pagecache_isize_extended-to-use-a-folio.patch
mm-free-non-hugetlb-large-folios-in-a-batch.patch
mm-combine-free_the_page-and-free_unref_page.patch
mm-inline-destroy_large_folio-into-__folio_put_large.patch
mm-combine-__folio_put_small-__folio_put_large-and-__folio_put.patch
mm-convert-free_zone_device_page-to-free_zone_device_folio.patch
doc-improve-the-description-of-__folio_mark_dirty.patch
buffer-add-kernel-doc-for-block_dirty_folio.patch
buffer-add-kernel-doc-for-try_to_free_buffers.patch
buffer-fix-__bread-and-__bread_gfp-kernel-doc.patch
buffer-add-kernel-doc-for-brelse-and-__brelse.patch
buffer-add-kernel-doc-for-bforget-and-__bforget.patch
buffer-improve-bdev_getblk-documentation.patch
doc-split-bufferrst-out-of-api-summaryrst.patch
doc-split-bufferrst-out-of-api-summaryrst-fix.patch
mm-memory-failure-remove-fsdax_pgoff-argument-from-__add_to_kill.patch
mm-memory-failure-pass-addr-to-__add_to_kill.patch
mm-return-the-address-from-page_mapped_in_vma.patch
mm-make-page_mapped_in_vma-conditional-on-config_memory_failure.patch
mm-memory-failure-convert-shake_page-to-shake_folio.patch
mm-convert-hugetlb_page_mapping_lock_write-to-folio.patch
mm-memory-failure-convert-memory_failure-to-use-a-folio.patch
mm-memory-failure-convert-hwpoison_user_mappings-to-take-a-folio.patch
mm-memory-failure-add-some-folio-conversions-to-unpoison_memory.patch
mm-memory-failure-use-folio-functions-throughout-collect_procs.patch
mm-memory-failure-pass-the-folio-to-collect_procs_ksm.patch
fscrypt-convert-bh_get_inode_and_lblk_num-to-use-a-folio.patch
f2fs-convert-f2fs_clear_page_cache_dirty_tag-to-use-a-folio.patch
memory-failure-remove-calls-to-page_mapping.patch
migrate-expand-the-use-of-folio-in-__migrate_device_pages.patch
userfault-expand-folio-use-in-mfill_atomic_install_pte.patch
mm-remove-page_mapping.patch
mm-remove-page_cache_alloc.patch
mm-remove-put_devmap_managed_page.patch
mm-convert-put_devmap_managed_page_refs-to-put_devmap_managed_folio_refs.patch
mm-remove-page_ref_sub_return.patch
gup-use-folios-for-gup_devmap.patch
mm-add-kernel-doc-for-folio_mark_accessed.patch
mm-remove-pagereferenced.patch
