+ mm-rmap-track-whether-the-page-vma-mapped-pgoff-is-anonymous.patch added to mm-unstable branch

The patch titled
     Subject: mm/rmap: track whether the page VMA mapped pgoff is anonymous
has been added to the -mm mm-unstable branch.  Its filename is
     mm-rmap-track-whether-the-page-vma-mapped-pgoff-is-anonymous.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-rmap-track-whether-the-page-vma-mapped-pgoff-is-anonymous.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: "Lorenzo Stoakes (ARM)" <[email protected]>
Subject: mm/rmap: track whether the page VMA mapped pgoff is anonymous
Date: Thu, 13 Aug 2026 18:32:27 +0100

Update the page_vma_mapped_walk structure to track whether the pgoff being
tracked is an anonymous pgoff or not and update the comments to reflect
this.

This is necessary in order to determine the correct VMA page offset in
vma_address_end() when pvmw->nr_pages > 1.

Also document that pvmw->pgoff is meaningless for pvmw->nr_pages == 1 and
for KSM.

Do not set this field where pgoff is not specified.

This is laying the groundwork for eventually using anonymous page offsets
as the index for all anonymous folios.

No functional change intended.

Link: https://lore.kernel.org/20260813-b4-scalable-cow-virt-pgoff-v5-10-c21581c0c3c8@kernel.org
Signed-off-by: Lorenzo Stoakes (ARM) <[email protected]>
Acked-by: David Hildenbrand (Arm) <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Deucher <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Alistair Popple <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Baolin Wang <[email protected]>
Cc: Baoquan He <[email protected]>
Cc: Barry Song <[email protected]>
Cc: Boris Brezillon <[email protected]>
Cc: Byungchul Park <[email protected]>
Cc: Chengming Zhou <[email protected]>
Cc: Chris Li <[email protected]>
Cc: Christan König <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Claudio Imbrenda <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: Dev Jain <[email protected]>
Cc: Gerald Schaefer <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Gregory Price (Meta) <[email protected]>
Cc: Harry Yoo <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Huang Ray <[email protected]>
Cc: "Huang, Ying" <[email protected]>
Cc: Ian Rogers <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: James Clark <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Jann Horn <[email protected]>
Cc: Janosch Frank <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Joshua Hahn <[email protected]>
Cc: Kairui Song <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Kemeng Shi <[email protected]>
Cc: Lance Yang <[email protected]>
Cc: Liam R. Howlett <[email protected]>
Cc: Liviu Dudau <[email protected]>
Cc: Maarten Lankhorst <[email protected]>
Cc: Marc Rutland <[email protected]>
Cc: "Masami Hiramatsu (Google)" <[email protected]>
Cc: Matthew Auld <[email protected]>
Cc: Matthew Brost <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Maxime Ripard <[email protected]>
Cc: Miaohe Lin <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Namhyung kim <[email protected]>
Cc: Naoya Horiguchi <[email protected]>
Cc: Nhat Pham <[email protected]>
Cc: Nico Pache <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Pedro Falcato <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rakie Kim <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Ryan Roberts <[email protected]>
Cc: Steven Price <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Thomas Hellström <[email protected]>
Cc: Thomas Zimemrmann <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: xu xin <[email protected]>
Cc: Zi Yan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---

 include/linux/rmap.h |    4 +++-
 mm/rmap.c            |    2 ++
 2 files changed, 5 insertions(+), 1 deletion(-)

--- a/include/linux/rmap.h~mm-rmap-track-whether-the-page-vma-mapped-pgoff-is-anonymous
+++ a/include/linux/rmap.h
@@ -864,13 +864,14 @@ struct page *make_device_exclusive(struc
 struct page_vma_mapped_walk {
 	unsigned long pfn;
 	unsigned long nr_pages;
-	pgoff_t pgoff;
+	pgoff_t pgoff;	/* Only meaningful if nr_pages > 1 and not a KSM walk */
 	struct vm_area_struct *vma;
 	unsigned long address;
 	pmd_t *pmd;
 	pte_t *pte;
 	spinlock_t *ptl;
 	unsigned int flags;
+	bool pgoff_is_anon : 1;
 };
 
 #define DEFINE_FOLIO_VMA_WALK(name, _folio, _vma, _address, _flags)	\
@@ -881,6 +882,7 @@ struct page_vma_mapped_walk {
 		.vma = _vma,						\
 		.address = _address,					\
 		.flags = _flags,					\
+		.pgoff_is_anon = folio_test_anon(_folio),		\
 	}
 
 static inline void page_vma_mapped_walk_done(struct page_vma_mapped_walk *pvmw)
--- a/mm/rmap.c~mm-rmap-track-whether-the-page-vma-mapped-pgoff-is-anonymous
+++ a/mm/rmap.c
@@ -1240,6 +1240,7 @@ static bool mapping_wrprotect_range_one(
 		.vma		= vma,
 		.address	= address,
 		.flags		= PVMW_SYNC,
+		.pgoff_is_anon	= false,
 	};
 
 	state->cleaned += page_vma_mkclean_one(&pvmw);
@@ -1317,6 +1318,7 @@ int pfn_mkclean_range(unsigned long pfn,
 		.pgoff		= pgoff,
 		.vma		= vma,
 		.flags		= PVMW_SYNC,
+		.pgoff_is_anon	= false,
 	};
 
 	if (invalid_mkclean_vma(vma, NULL))
_

Patches currently in -mm which might be from [email protected] are

mm-vma-introduce-vma-anon-page-offset-field-and-add-helpers.patch
mm-provide-vma_is_cow_mapping-and-remove-is_cow_mapping.patch
mm-introduce-linear_anon_page_index.patch
mm-abstract-vma_address-and-introduce-vma_anon_address.patch
mm-update-print_bad_page_map-to-show-anon-index-if-appropriate.patch
mm-introduce-and-use-vma_filebacked_address.patch
mm-vma-fix-self-merge-check-in-copy_vma.patch
tools-testing-vma-add-tests-for-copy_vma-self-merge.patch
mm-propagate-vma-anonymous-page-offset-on-map-remap-split-merge.patch
mm-rmap-track-whether-the-page-vma-mapped-pgoff-is-anonymous.patch
mm-clean-up-vma_address_end.patch
mm-huge_memory-update-remove_migration_pmd-to-accept-a-folio.patch
mm-migrate-calculate-large-folio-page-index-using-pfn.patch
mm-rmap-use-anon-pgoff-to-track-map_private-file-backed-anon-folios.patch
tools-testing-vma-expand-vma-merge-tests-to-assert-anon-pgoff.patch
tools-testing-selftests-mm-test-anonymous-page-offset-merge-behaviour.patch
mm-add-some-missing-includes-to-mm-local-headers.patch
maintainers-add-drivers-char-memc-to-mm-misc-memory-mapping-sections.patch