Message-ID: <20250717115212.1825089-1-david@redhat.com>
Date: Thu, 17 Jul 2025 13:52:03 +0200
From: David Hildenbrand <david@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: linux-mm@...ck.org,
	xen-devel@...ts.xenproject.org,
	linux-fsdevel@...r.kernel.org,
	nvdimm@...ts.linux.dev,
	David Hildenbrand <david@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Juergen Gross <jgross@...e.com>,
	Stefano Stabellini <sstabellini@...nel.org>,
	Oleksandr Tyshchenko <oleksandr_tyshchenko@...m.com>,
	Dan Williams <dan.j.williams@...el.com>,
	Matthew Wilcox <willy@...radead.org>,
	Jan Kara <jack@...e.cz>,
	Alexander Viro <viro@...iv.linux.org.uk>,
	Christian Brauner <brauner@...nel.org>,
	Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
	"Liam R. Howlett" <Liam.Howlett@...cle.com>,
	Vlastimil Babka <vbabka@...e.cz>,
	Mike Rapoport <rppt@...nel.org>,
	Suren Baghdasaryan <surenb@...gle.com>,
	Michal Hocko <mhocko@...e.com>,
	Zi Yan <ziy@...dia.com>,
	Baolin Wang <baolin.wang@...ux.alibaba.com>,
	Nico Pache <npache@...hat.com>,
	Ryan Roberts <ryan.roberts@....com>,
	Dev Jain <dev.jain@....com>,
	Barry Song <baohua@...nel.org>,
	Jann Horn <jannh@...gle.com>,
	Pedro Falcato <pfalcato@...e.de>,
	Hugh Dickins <hughd@...gle.com>,
	Oscar Salvador <osalvador@...e.de>,
	Lance Yang <lance.yang@...ux.dev>
Subject: [PATCH v2 0/9] mm: vm_normal_page*() improvements

Based on mm/mm-new from today that contains [2].

Cleanup and unify vm_normal_page_*() handling, also marking the
huge zerofolio as special in the PMD. Add+use vm_normal_page_pud() and
cleanup that XEN vm_ops->find_special_page thingy.

There are plans of using vm_normal_page_*() more widely soon.

Briefly tested on UML (making sure vm_normal_page() still works as expected
without pte_special() support) and on x86-64 with a bunch of tests.
Cross-compiled for a variety of weird archs.

[1] https://lkml.kernel.org/r/20250617154345.2494405-1-david@redhat.com
[2] https://lkml.kernel.org/r/cover.1752499009.git.luizcap@redhat.com

v1 -> v2:
* "mm/memory: convert print_bad_pte() to print_bad_page_map()"
 -> Don't use pgdp_get(), because it's broken on some arm configs
 -> Extend patch description
 -> Don't use pmd_val(pmdp_get()), because that doesn't work on some
    m68k configs
* Added RBs

RFC -> v1:
* Dropped the highest_memmap_pfn removal stuff and instead added
  "mm/memory: convert print_bad_pte() to print_bad_page_map()"
* Dropped "mm: compare pfns only if the entry is present when inserting
  pfns/pages" for now, will probably clean that up separately.
* Dropped "mm: remove "horrible special case to handle copy-on-write
  behaviour"", and "mm: drop addr parameter from vm_normal_*_pmd()" will
  require more thought
* "mm/huge_memory: support huge zero folio in vmf_insert_folio_pmd()"
 -> Extend patch description.
* "fs/dax: use vmf_insert_folio_pmd() to insert the huge zero folio"
 -> Extend patch description.
* "mm/huge_memory: mark PMD mappings of the huge zero folio special"
 -> Remove comment from vm_normal_page_pmd().
* "mm/memory: factor out common code from vm_normal_page_*()"
 -> Adjust to print_bad_page_map()/highest_memmap_pfn changes.
 -> Add proper kernel doc to all involved functions
* "mm: introduce and use vm_normal_page_pud()"
 -> Adjust to print_bad_page_map() changes.

Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Juergen Gross <jgross@...e.com>
Cc: Stefano Stabellini <sstabellini@...nel.org>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@...m.com>
Cc: Dan Williams <dan.j.williams@...el.com>
Cc: Matthew Wilcox <willy@...radead.org>
Cc: Jan Kara <jack@...e.cz>
Cc: Alexander Viro <viro@...iv.linux.org.uk>
Cc: Christian Brauner <brauner@...nel.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
Cc: "Liam R. Howlett" <Liam.Howlett@...cle.com>
Cc: Vlastimil Babka <vbabka@...e.cz>
Cc: Mike Rapoport <rppt@...nel.org>
Cc: Suren Baghdasaryan <surenb@...gle.com>
Cc: Michal Hocko <mhocko@...e.com>
Cc: Zi Yan <ziy@...dia.com>
Cc: Baolin Wang <baolin.wang@...ux.alibaba.com>
Cc: Nico Pache <npache@...hat.com>
Cc: Ryan Roberts <ryan.roberts@....com>
Cc: Dev Jain <dev.jain@....com>
Cc: Barry Song <baohua@...nel.org>
Cc: Jann Horn <jannh@...gle.com>
Cc: Pedro Falcato <pfalcato@...e.de>
Cc: Hugh Dickins <hughd@...gle.com>
Cc: Oscar Salvador <osalvador@...e.de>
Cc: Lance Yang <lance.yang@...ux.dev>

David Hildenbrand (9):
  mm/huge_memory: move more common code into insert_pmd()
  mm/huge_memory: move more common code into insert_pud()
  mm/huge_memory: support huge zero folio in vmf_insert_folio_pmd()
  fs/dax: use vmf_insert_folio_pmd() to insert the huge zero folio
  mm/huge_memory: mark PMD mappings of the huge zero folio special
  mm/memory: convert print_bad_pte() to print_bad_page_map()
  mm/memory: factor out common code from vm_normal_page_*()
  mm: introduce and use vm_normal_page_pud()
  mm: rename vm_ops->find_special_page() to vm_ops->find_normal_page()

 drivers/xen/Kconfig              |   1 +
 drivers/xen/gntdev.c             |   5 +-
 fs/dax.c                         |  47 +----
 include/linux/mm.h               |  20 +-
 mm/Kconfig                       |   2 +
 mm/huge_memory.c                 | 119 ++++-------
 mm/memory.c                      | 346 ++++++++++++++++++++++---------
 mm/pagewalk.c                    |  20 +-
 tools/testing/vma/vma_internal.h |  18 +-
 9 files changed, 343 insertions(+), 235 deletions(-)


base-commit: 760b462b3921c5dc8bfa151d2d27a944e4e96081
-- 
2.50.1

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