Re: [PATCH v3 20/20] mm: stop maintaining the per-page mapcount of large... | linux-api

[PATCH v3 00/20] mm: MM owner tracking for large folios (!hugetlb) + CONFIG_NO_PAGE_MAPCOUNT · David Hildenbrand <hidden> · 2025-03-03
[PATCH v3 04/20] mm: move hugetlb specific things in folio to page[3] · David Hildenbrand <hidden> · 2025-03-03
[PATCH v3 02/20] mm: factor out large folio handling from folio_nr_pages() into folio_large_nr_pages() · David Hildenbrand <hidden> · 2025-03-03
[PATCH v3 03/20] mm: let _folio_nr_pages overlay memcg_data in first tail page · David Hildenbrand <hidden> · 2025-03-03
Re: [PATCH v3 03/20] mm: let _folio_nr_pages overlay memcg_data in first tail page · David Hildenbrand <hidden> · 2025-03-05
[PATCH v3 01/20] mm: factor out large folio handling from folio_order() into folio_large_order() · David Hildenbrand <hidden> · 2025-03-03
[PATCH v3 05/20] mm: move _pincount in folio to page[2] on 32bit · David Hildenbrand <hidden> · 2025-03-03
[PATCH v3 07/20] mm/rmap: pass dst_vma to folio_dup_file_rmap_pte() and friends · David Hildenbrand <hidden> · 2025-03-03
[PATCH v3 08/20] mm/rmap: pass vma to __folio_add_rmap() · David Hildenbrand <hidden> · 2025-03-03
[PATCH v3 06/20] mm: move _entire_mapcount in folio to page[2] on 32bit · David Hildenbrand <hidden> · 2025-03-03
[PATCH v3 14/20] mm: convert folio_likely_mapped_shared() to folio_maybe_mapped_shared() · David Hildenbrand <hidden> · 2025-03-03
[PATCH v3 12/20] mm/rmap: basic MM owner tracking for large folios (!hugetlb) · David Hildenbrand <hidden> · 2025-03-03
[PATCH v3 13/20] mm: Copy-on-Write (COW) reuse support for PTE-mapped THP · David Hildenbrand <hidden> · 2025-03-03
Re: [PATCH v3 13/20] mm: Copy-on-Write (COW) reuse support for PTE-mapped THP · Kairui Song <hidden> · 2025-04-19
Re: [PATCH v3 13/20] mm: Copy-on-Write (COW) reuse support for PTE-mapped THP · David Hildenbrand <hidden> · 2025-04-19
Re: [PATCH v3 13/20] mm: Copy-on-Write (COW) reuse support for PTE-mapped THP · David Hildenbrand <hidden> · 2025-04-19
Re: [PATCH v3 13/20] mm: Copy-on-Write (COW) reuse support for PTE-mapped THP · Kairui Song <hidden> · 2025-04-19
Re: [PATCH v3 13/20] mm: Copy-on-Write (COW) reuse support for PTE-mapped THP · Kairui Song <hidden> · 2025-04-22
Re: [PATCH v3 13/20] mm: Copy-on-Write (COW) reuse support for PTE-mapped THP · David Hildenbrand <hidden> · 2025-04-22
Re: [PATCH v3 13/20] mm: Copy-on-Write (COW) reuse support for PTE-mapped THP · Kairui Song <hidden> · 2025-04-19
[PATCH v3 09/20] mm/rmap: abstract large mapcount operations for large folios (!hugetlb) · David Hildenbrand <hidden> · 2025-03-03
[PATCH v3 16/20] fs/proc/page: remove per-page mapcount dependency for /proc/kpagecount (CONFIG_NO_PAGE_MAPCOUNT) · David Hildenbrand <hidden> · 2025-03-03
[PATCH v3 17/20] fs/proc/task_mmu: remove per-page mapcount dependency for PM_MMAP_EXCLUSIVE (CONFIG_NO_PAGE_MAPCOUNT) · David Hildenbrand <hidden> · 2025-03-03
[PATCH v3 15/20] mm: CONFIG_NO_PAGE_MAPCOUNT to prepare for not maintain per-page mapcounts in large folios · David Hildenbrand <hidden> · 2025-03-03
[PATCH v3 18/20] fs/proc/task_mmu: remove per-page mapcount dependency for "mapmax" (CONFIG_NO_PAGE_MAPCOUNT) · David Hildenbrand <hidden> · 2025-03-03
[PATCH v3 20/20] mm: stop maintaining the per-page mapcount of large folios (CONFIG_NO_PAGE_MAPCOUNT) · David Hildenbrand <hidden> · 2025-03-03
Re: [PATCH v3 20/20] mm: stop maintaining the per-page mapcount of large folios (CONFIG_NO_PAGE_MAPCOUNT) · Wei Yang <hidden> · 2025-10-14
Re: [PATCH v3 20/20] mm: stop maintaining the per-page mapcount of large folios (CONFIG_NO_PAGE_MAPCOUNT) · David Hildenbrand <hidden> · 2025-10-14
Re: [PATCH v3 20/20] mm: stop maintaining the per-page mapcount of large folios (CONFIG_NO_PAGE_MAPCOUNT) · Wei Yang <hidden> · 2025-10-14
Re: [PATCH v3 20/20] mm: stop maintaining the per-page mapcount of large folios (CONFIG_NO_PAGE_MAPCOUNT) · Matthew Wilcox <willy@infradead.org> · 2025-10-14
Re: [PATCH v3 20/20] mm: stop maintaining the per-page mapcount of large folios (CONFIG_NO_PAGE_MAPCOUNT) · David Hildenbrand <hidden> · 2025-10-14
Re: [PATCH v3 20/20] mm: stop maintaining the per-page mapcount of large folios (CONFIG_NO_PAGE_MAPCOUNT) · Wei Yang <hidden> · 2025-10-15
Re: [PATCH v3 20/20] mm: stop maintaining the per-page mapcount of large folios (CONFIG_NO_PAGE_MAPCOUNT) · David Hildenbrand <hidden> · 2025-10-20
[PATCH v3 10/20] bit_spinlock: __always_inline (un)lock functions · David Hildenbrand <hidden> · 2025-03-03
[PATCH v3 11/20] mm/rmap: use folio_large_nr_pages() in add/remove functions · David Hildenbrand <hidden> · 2025-03-03
[PATCH v3 19/20] fs/proc/task_mmu: remove per-page mapcount dependency for smaps/smaps_rollup (CONFIG_NO_PAGE_MAPCOUNT) · David Hildenbrand <hidden> · 2025-03-03
Re: [PATCH v3 00/20] mm: MM owner tracking for large folios (!hugetlb) + CONFIG_NO_PAGE_MAPCOUNT · Andrew Morton <akpm@linux-foundation.org> · 2025-03-03
Re: [PATCH v3 00/20] mm: MM owner tracking for large folios (!hugetlb) + CONFIG_NO_PAGE_MAPCOUNT · David Hildenbrand <hidden> · 2025-03-04

Re: [PATCH v3 20/20] mm: stop maintaining the per-page mapcount of large folios (CONFIG_NO_PAGE_MAPCOUNT)

From: Matthew Wilcox <willy@infradead.org>
Date: 2025-10-14 14:32:47
Also in: cgroups, linux-doc, linux-fsdevel, linux-mm, lkml

On Tue, Oct 14, 2025 at 02:59:30PM +0200, David Hildenbrand wrote:

quoted

As commit 349994cf61e6 mentioned, we don't support partially mapped PUD-sized
folio yet.

We do support partially mapped PUD-sized folios I think, but not anonymous
PUD-sized folios.

I don't think so?  The only mechanism I know of to allocate PUD-sized
chunks of memory is hugetlb, and that doesn't permit partial mappings.

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