From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 009105372E3 for ; Tue, 13 Oct 2026 18:51:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791917508; cv=none; b=ANdA9aIy5X9UkcoHy4W5lnfEIeA+6Nj/qm6/vB2LJBvJM5gJ6QDiNJ8pixlWLkUlIkfn1lLEkpymplZZiBsL12dT1yHyyFU/BAkNHfjZEG8y77g2jNRllgM/uPG5g7mQF6WhG+b1PW6jvZMEvN6amGx2IL0JLZeOb0sdg/+DtvI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791917508; c=relaxed/simple; bh=9LZsnl6nQQDg6iLnjcJk0BWHeSt8qbOumUCe0ehgO14=; h=Date:To:From:Subject:Message-Id; b=Hyy8xE0Sx7dphRWnorbLSAjKmggH6Iuykc8MOwpEKONkrJAA1eb8Bjv3LpFlm9eiExFLNHTGb9hFmYrUKq2Z3xN87pAN0e1jElcNMVobdXhB5PL31sCW+ZcSXc9PInkPbqzXsMqVrZFbmvXSqnaWQR8dpYg9uHP5aqPnWKqQBwQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=vQ+ybINV; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="vQ+ybINV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C44301F00893; Tue, 13 Oct 2026 18:51:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1791917504; bh=7olfmKCX9zow7py3uYV4ME0zO4CP0yPfmRrQ7PlnxJM=; h=Date:To:From:Subject; b=vQ+ybINVIMJADAEOGqjKRlJFnjUUt8bjtfO5aSnXQ0gIXa2Z2bCh8MPNIUPy9C7Ge BMqS4wix0/20OlW/9vRWsT1SkfQ/9vhqWytaeIezJ3Yznt6tGnZYFNnzOy8HsxYiTf g7OngJMRydN0OwIcvVScLmvlHd6dWj+TEsW1WU/c= Date: Tue, 13 Oct 2026 11:51:44 -0700 To: mm-commits@vger.kernel.org,ljs@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-vma-add-vma_is_mm_managed-predicates.patch added to mm-unstable branch Message-Id: <20261013185144.C44301F00893@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm/vma: add vma[_flags]_is_mm_managed() predicates has been added to the -mm mm-unstable branch. Its filename is mm-vma-add-vma_is_mm_managed-predicates.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-vma-add-vma_is_mm_managed-predicates.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: "Lorenzo Stoakes (ARM)" Subject: mm/vma: add vma[_flags]_is_mm_managed() predicates Date: Tue, 13 Oct 2026 16:04:55 +0100 Rather than referring to VMA flags with uncertain meaning, add a new predicate that explicitly describes what absence of the VMA_PFNMAP_BIT and VMA_MIXEDMAP_BIT flags means, and then refer to that function for determining VMA mergeability. If neither of these flags are set, that means the contents of the mapping are managed by core mm. Otherwise they are instead owned by some other kernel component, usually a driver: the memory may be MMIO, kernel-allocated pages or even ordinary pages the driver maps itself, but core mm must not populate, reclaim, migrate, copy-on-write or merge the range itself. We initially also treat VMA_IO_BIT as implying a mapping is not mm-managed, as by implication it cannot be. (mlock() also sets VMA_IO_BIT transiently on ordinary VMAs while locking them, which is addressed later in this series.) However the intent is to in future remove this, as no mapping should be marked as an I/O mapping without also being marked with VMA_PFNMAP_BIT. This forms the basis of further work intended to improve how we express VMA properties such as this. Also update the VMA userland tests to reflect the change. No functional change intended. Link: https://lore.kernel.org/20261013-b4-mmap-prepare-vma-flag-sanify-v6-15-1aa3c9b139f9@kernel.org Signed-off-by: Lorenzo Stoakes (ARM) Signed-off-by: Andrew Morton Reviewed-by: Zi Yan Reviewed-by: Suren Baghdasaryan Acked-by: David Hildenbrand (Arm) Cc: Liam R. Howlett Cc: Vlastimil Babka Cc: Jann Horn Cc: Pedro Falcato Cc: Mike Rapoport Cc: Michal Hocko Cc: Jonathan Corbet Cc: Greg Kroah-Hartman Cc: Dennis Dalessandro Cc: Jason Gunthorpe Cc: Leon Romanovsky Cc: Paul Moore Cc: Stephen Smalley Cc: Jaroslav Kysela Cc: Takashi Iwai Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: Andrii Nakryiko Cc: Eduard Zingerman Cc: Kumar Kartikeya Dwivedi Cc: Baolin Wang Cc: Nico Pache Cc: Ryan Roberts Cc: Dev Jain Cc: Barry Song Cc: Lance Yang Cc: Usama Arif Cc: Kiryl Shutsemau Cc: Doug Gilbert Cc: James Bottomley Cc: Martin K. Petersen Cc: Simona Vetter Cc: Helge Deller Cc: Sebastian Reichel Cc: John Hubbard Cc: Peter Xu Cc: Masami Hiramatsu Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: Arnaldo Carvalho de Melo Cc: Namhyung Kim Cc: Mark Rutland Cc: Rik van Riel Cc: Harry Yoo Cc: Juri Lelli Cc: Vincent Guittot Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: Thomas Zimmermann Cc: David Airlie Cc: Will Deacon Cc: Aneesh Kumar K.V Cc: Nicholas Piggin Cc: Arnd Bergmann Cc: Muchun Song Cc: Oscar Salvador Cc: Matthew Wilcox (Oracle) Cc: Jan Kara Cc: Marc Zyngier Cc: Oliver Upton Cc: Catalin Marinas Cc: Madhavan Srinivasan Cc: Anup Patel Cc: Paul Walmsley Cc: Palmer Dabbelt Cc: Albert Ou Cc: Christian Borntraeger Cc: Janosch Frank Cc: Claudio Imbrenda Cc: Alexander Gordeev Cc: Gerald Schaefer Cc: Heiko Carstens Cc: Vasily Gorbik Cc: David S. Miller Cc: Andreas Larsson Cc: Al Viro Cc: Christian Brauner Cc: Matthew Brost Cc: Joshua Hahn Cc: Rakie Kim Cc: Byungchul Park Cc: Gregory Price Cc: Ying Huang Cc: Alistair Popple Cc: Chris Li Cc: Kairui Song Cc: Kemeng Shi Cc: Nhat Pham Cc: Baoquan He Cc: Youngjun Park Cc: Johannes Weiner Cc: Qi Zheng Cc: Shakeel Butt Cc: Axel Rasmussen Cc: Yuanchu Xie Cc: Wei Xu Cc: Chengming Zhou Cc: Michal Hocko Cc: Miklos Szeredi Cc: Xu Xin Cc: Ihor Solodrai Cc: Bert Karwatzki --- include/linux/mm.h | 53 +++++++++++++++++++++++++++++- tools/testing/vma/include/dup.h | 29 +++++++++++++++- 2 files changed, 80 insertions(+), 2 deletions(-) --- a/include/linux/mm.h~mm-vma-add-vma_is_mm_managed-predicates +++ a/include/linux/mm.h @@ -1614,6 +1614,41 @@ static inline bool vma_is_shared_maywrit } /** + * vma_flags_is_mm_managed() - Do the specified VMA flags indicate that the + * contents of the VMA are managed by core mm? + * @flags: The VMA flags to test. + * + * Such a mapping is one established by a simple mmap() or brk() with no driver + * or other kernel component involved. + * + * They are rmappable, and core mm services rmap operations including reclaim, + * as well as population, CoW and merge/split (if eligible). + * + * Mappings which fail this test are those where this is not the case - + * e.g. MMIO, user-mapped kernel pages, udmabuf (pfnmap shmem), etc. + * + * Returns: true if the flags indicate an mm-managed mapping. + */ +static inline bool vma_flags_is_mm_managed(const vma_flags_t *flags) +{ + return !vma_flags_test_any(flags, VMA_PFNMAP_BIT, VMA_MIXEDMAP_BIT, + VMA_IO_BIT); +} + +/** + * vma_is_mm_managed() - Are the contents of @vma managed by core mm? + * @vma: The VMA to test. + * + * See vma_flags_is_mm_managed() for a description of this property. + * + * Returns: true if the VMA is mm-managed. + */ +static inline bool vma_is_mm_managed(const struct vm_area_struct *vma) +{ + return vma_flags_is_mm_managed(&vma->flags); +} + +/** * vma_flags_can_merge() - Do the specified VMA flags permit the VMA to be * merged with another? * @flags: The VMA flags to test. @@ -1621,7 +1656,23 @@ static inline bool vma_is_shared_maywrit */ static inline bool vma_flags_can_merge(const vma_flags_t *flags) { - return !vma_flags_test_any_mask(flags, VMA_SPECIAL_FLAGS); + /* + * VMA merging assumes that a VMA's flags and fields completely describe + * its state. + * + * However, mappings which are not mm-managed may have established state + * upon mapping not embodied in any attribute of the VMA. + * + * Additionally, private (CoW) PFN maps encode the source PFN of the + * range in vma->vm_pgoff, which may otherwise cause spurious merges. + */ + if (!vma_flags_is_mm_managed(flags)) + return false; + /* VMA explicitly marked as being unmergeable. */ + if (vma_flags_test(flags, VMA_DONTEXPAND_BIT)) + return false; + + return true; } /** --- a/tools/testing/vma/include/dup.h~mm-vma-add-vma_is_mm_managed-predicates +++ a/tools/testing/vma/include/dup.h @@ -1665,7 +1665,34 @@ static inline bool file_is_dev_zero(cons return file && file->f_op == &zero_fops; } +static inline bool vma_flags_is_mm_managed(const vma_flags_t *flags) +{ + return !vma_flags_test_any(flags, VMA_PFNMAP_BIT, VMA_MIXEDMAP_BIT, + VMA_IO_BIT); +} + +static inline bool vma_is_mm_managed(const struct vm_area_struct *vma) +{ + return vma_flags_is_mm_managed(&vma->flags); +} + static inline bool vma_flags_can_merge(const vma_flags_t *flags) { - return !vma_flags_test_any_mask(flags, VMA_SPECIAL_FLAGS); + /* + * VMA merging assumes that a VMA's flags and fields completely describe + * its state. + * + * However, mappings which are not mm-managed may have established state + * upon mapping not embodied in any attribute of the VMA. + * + * Additionally, private (CoW) PFN maps encode the source PFN of the + * range in vma->vm_pgoff, which may otherwise cause spurious merges. + */ + if (!vma_flags_is_mm_managed(flags)) + return false; + /* VMA explicitly marked as being unmergeable. */ + if (vma_flags_test(flags, VMA_DONTEXPAND_BIT)) + return false; + + return true; } _ Patches currently in -mm which might be from ljs@kernel.org are mm-vma-fix-mmap_prepare-file-handling-remove-file_doesnt_need_get.patch mm-vma-introduce-and-use-vma_can_merge.patch mm-consistently-validate-vma-state-after-mmap-hooks.patch mm-vma-ensure-mmap_prepare-doesnt-set-actions-on-a-mergeable-vma.patch mm-make-map_kernel_pages_-internal-and-unexported.patch mm-vma-tidy-up-map-kernel-pages-enum-values.patch mm-assert-mmap-lock-held-use-new-flags-api-in-vm_insert_page.patch mm-add-mmap-action-for-discontiguous-kernel-page-mapping.patch docs-filesystems-update-mmap_prepare-docs-for-discontig-kernel-pgs.patch drivers-usb-mon-update-to-use-mmap_prepare-map-kernel-pages.patch infiniband-update-hfi1-to-use-remap_vmalloc_range.patch selinux-reject-writable-opens-of-policy-file-drop-mmap-shared-write-check.patch alsa-pcm-use-vm_insert_page-to-map-pcm-status-page.patch bpf-arena-mark-arena_map_mmap-mappings-vm_mixedmap.patch mm-vma-add-vma_is_mm_managed-predicates.patch mm-vma-only-allow-mmap-to-clear-vma_maywrite_bit-if-not-mm-managed.patch mm-vma-add-and-use-vma__is_fixed_mapping.patch scsi-sg-convert-mmap-hook-to-mmap_prepare-and-rework.patch fbdev-defio-assert-fbinfo_virtfb-drop-vm_io-add-vm_mixedmap.patch hsi-cmt_speech-convert-mmap-hook-to-mmap_prepare-refactor.patch mm-gup-error-out-early-on-vma_mayread_bit-vmas.patch uprobes-remove-vm_io-set-vm_mixedmap-for-mapped-kernel-pages.patch mm-mlock-clear-vma_locked_mask-over-mmap-callback.patch mm-mlock-eliminate-weird-vma_io_bit-abuse-and-simplify.patch mm-vma-enforce-that-mm-managed-mappings-may-not-set-vma_io_bit.patch mm-remove-vma_io_bit-check-in-vma_is_mm_managed.patch mm-remove-hugetlb_inlineh.patch mm-rename-is_vm_hugetlb_page-to-vma_is_hugetlb.patch mm-drop-some-redundant-checks-around-hugetlb-vmas.patch mm-vma-introduce-vma_is_mm_backed.patch mm-madvise-update-is_valid_guard_vma-to-use-vma_is_mm_backed.patch mm-uffd-use-predicates-for-userfaultfd-checks.patch mm-madvise-use-predicates-for-madvise-madv_dofork.patch mm-eliminate-vma_special_flags-usage-when-hugetlb-explicitly-tested.patch mm-eliminate-vma_special_flags-check-in-lru_gen_look_around.patch mm-avoid-use-of-vma_special_flags-in-migrate_vma_setup.patch mm-eliminate-vm_special-vma_special_flags.patch fuse-dax-do-not-set-vm_mixedmap.patch mm-huge_memory-remove-vma_is_special_huge.patch mm-vma-const-ify-vma_assert_stabilised-and-associated-functions.patch mm-implement-and-use-vma_has_anon_rmap-silence-kcsan.patch mm-update-comments-to-refer-to-anon-rmap-rather-than-anon_vma.patch mm-vma-dont-remove-vma-from-rmap-if-pgoff-unchanged.patch