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 0D4B238AC78 for ; Sat, 10 Oct 2026 21:39:38 +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=1791668383; cv=none; b=nML+YJln5OfZZIrSW9tvdOW6SScxxaKB/M556/V0NGzi/H7Ff1kv7a48QsoyaPMSi1YAY64de70IGzZHXr6BKzXORLlSTwaFXpoL3rOYKVs0Sy6qey7+zt6yGzaQ4DxHmWmFFMZ6Q6Tjc18wMpduAY7RcjN6KcRe+3oqNf47BSw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791668383; c=relaxed/simple; bh=RR83JOPfkPSHPvQUuiqugsfcUNEt/ZyZjEEYkVECOyo=; h=Date:To:From:Subject:Message-Id; b=jnOv3wG8hnCY7WfPhOXP+HBsgdeGoO5TZadSlPIo/vNUz2Vd9niKWr7jguUB5KlSV3z26p7JDJpXusgodgbNpNz4CKI9yHdfTp+DfZoBKsAaNc4MzvjI90t4kXj6Ea1Up0fqPCwhsPjYEo59lx/yKQJVgdX9687Txb7FZDZ7tGg= 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=r7WhGMXI; 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="r7WhGMXI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9CE2D1F00899; Sat, 10 Oct 2026 21:39:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1791668378; bh=d1Iwunrv3fzRBNxfqUjYqBZ4lzrhrzOhra+a4YGrVlg=; h=Date:To:From:Subject; b=r7WhGMXIW2Ng1y9SIJZXh+9raizXqpxo4C4rp2gJweg25zJNpPMkeWUq6XQAOt4sk Wu17nb4mZeRdH2vZa5Bg2TlRkQXT4jwvDAq0kYW/WEXmqrbpoc1Aae8G3vgIFKW80M 0uCMFPz2e3PCRcCXrZKPeugYONC40WniFGJ7vU9E= Date: Sat, 10 Oct 2026 14:39:38 -0700 To: mm-commits@vger.kernel.org,ljs@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: [to-be-updated] mm-vma-add-and-use-vma__is_fixed_mapping.patch removed from -mm tree Message-Id: <20261010213938.9CE2D1F00899@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: mm/vma: add and use vma_[flags]_is_fixed_mapping has been removed from the -mm tree. Its filename was mm-vma-add-and-use-vma__is_fixed_mapping.patch This patch was dropped because an updated version will be issued ------------------------------------------------------ From: "Lorenzo Stoakes (ARM)" Subject: mm/vma: add and use vma_[flags]_is_fixed_mapping Date: Sat, 03 Oct 2026 17:32:47 +0100 This determines whether a VMA cannot be expanded or merged because what they mapped was determined to be a set size at mmap time. This typically refers to mappings not managed by core mm, however VMA_DONTEXPAND_BIT is not reliably set alongside VMA_PFNMAP_BIT or VMA_MIXEDMAP_BIT, so we must explicitly test for this for now. We also explicitly test for VMA_PFNMAP_BIT as VMA_DONTEXPAND_BIT may not be set for VMA_PFNMAP_BIT's despite the one implying the other. Use this predicate in vma_flags_can_merge() and in check_prep_vma() in the mremap logic testing to see if mremap() can expand the VMA. The criteria for khugepaged and MADV_COLLAPSE eligibility in __thp_vma_allowable_orders() are precisely those for mergeability, so use vma_can_merge() there (with an expanded comment). This obviates the need for the VM_NO_KHUGEPAGED mask, so remove it. Hugetlb VMAs remain excluded from khugepaged as hugetlbfs always sets VMA_DONTEXPAND_BIT. Also update the userland VMA tests to reflect the change. No functional change intended. Link: https://lore.kernel.org/20261003-b4-mmap-prepare-vma-flag-sanify-v4-16-a1f052500fd7@kernel.org Signed-off-by: Lorenzo Stoakes (ARM) Signed-off-by: Andrew Morton Reviewed-by: Zi Yan Reviewed-by: Suren Baghdasaryan Cc: Liam R. Howlett Cc: Vlastimil Babka Cc: Jann Horn Cc: Pedro Falcato Cc: David Hildenbrand 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 --- include/linux/mm.h | 39 ++++++++++++++++++++++++++---- mm/huge_memory.c | 11 +++++--- mm/mremap.c | 5 +-- tools/testing/vma/include/dup.h | 16 +++++++++++- 4 files changed, 59 insertions(+), 12 deletions(-) --- a/include/linux/mm.h~mm-vma-add-and-use-vma__is_fixed_mapping +++ a/include/linux/mm.h @@ -601,9 +601,6 @@ enum { #define VMA_REMAP_FLAGS mk_vma_flags(VMA_IO_BIT, VMA_PFNMAP_BIT, \ VMA_DONTEXPAND_BIT, VMA_DONTDUMP_BIT) -/* This mask prevents VMA from being scanned with khugepaged */ -#define VM_NO_KHUGEPAGED (VM_SPECIAL | VM_HUGETLB) - /* This mask defines which mm->def_flags a process can inherit its parent */ #define VM_INIT_DEF_MASK VM_NOHUGEPAGE @@ -1649,6 +1646,40 @@ static inline bool vma_is_mm_managed(con } /** + * vma_flags_is_fixed_mapping() - Do the specified VMA flags indicate that this + * is a fixed mapping that cannot be expanded or merged? + * @flags: The VMA flags to test. + * + * Fixed mappings are those whose size is set at the point of mmap (for + * instance, a mapping of a fixed range of memory established by a driver), + * and thus cannot be expanded or merged. + * + * Returns: true if the flags indicate a fixed mapping. + */ +static inline bool vma_flags_is_fixed_mapping(const vma_flags_t *flags) +{ + /* + * VMA_PFNMAP_BIT should imply VMA_DONTEXPAND_BIT, but some callers set + * only the former. + */ + return vma_flags_test_any(flags, VMA_PFNMAP_BIT, VMA_DONTEXPAND_BIT); +} + +/** + * vma_is_fixed_mapping() - Is this VMA a fixed mapping that cannot be + * expanded or merged? + * @vma: The VMA to test. + * + * See vma_flags_is_fixed_mapping() for a description of this property. + * + * Returns: true if the VMA maps a fixed mapping. + */ +static inline bool vma_is_fixed_mapping(const struct vm_area_struct *vma) +{ + return vma_flags_is_fixed_mapping(&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. @@ -1669,7 +1700,7 @@ static inline bool vma_flags_can_merge(c if (!vma_flags_is_mm_managed(flags)) return false; /* VMA explicitly marked as being unmergeable. */ - if (vma_flags_test(flags, VMA_DONTEXPAND_BIT)) + if (vma_flags_is_fixed_mapping(flags)) return false; return true; --- a/mm/huge_memory.c~mm-vma-add-and-use-vma__is_fixed_mapping +++ a/mm/huge_memory.c @@ -212,11 +212,14 @@ unsigned long __thp_vma_allowable_orders return in_pf ? orders : 0; /* - * khugepaged special VMA and hugetlb VMA. - * Must be checked after dax since some dax mappings may have - * VM_MIXEDMAP set. + * khugepaged moves data from VMAs once collapsed, after they have been + * faulted in, relying on refaulting for file-backed memory. + * + * Mappings not managed by core mm cannot be reliably reconstructed from + * page faults, and fixed mappings (including hugetlb) may well be + * mm-managed - precisely the mappings which cannot be merged. */ - if (!in_pf && !smaps && (vm_flags & VM_NO_KHUGEPAGED)) + if (!in_pf && !smaps && !vma_can_merge(vma)) return 0; /* --- a/mm/mremap.c~mm-vma-add-and-use-vma__is_fixed_mapping +++ a/mm/mremap.c @@ -1822,8 +1822,7 @@ static int check_prep_vma(struct vma_rem return -EINVAL; } - if ((vrm->flags & MREMAP_DONTUNMAP) && - vma_test_any(vma, VMA_DONTEXPAND_BIT, VMA_PFNMAP_BIT)) + if ((vrm->flags & MREMAP_DONTUNMAP) && vma_is_fixed_mapping(vma)) return -EINVAL; /* @@ -1861,7 +1860,7 @@ static int check_prep_vma(struct vma_rem if (pgoff + (new_len >> PAGE_SHIFT) < pgoff) return -EINVAL; - if (vma_test_any(vma, VMA_DONTEXPAND_BIT, VMA_PFNMAP_BIT)) + if (vma_is_fixed_mapping(vma)) return -EFAULT; if (!mlock_future_ok(mm, vma_test(vma, VMA_LOCKED_BIT), vrm->delta)) --- a/tools/testing/vma/include/dup.h~mm-vma-add-and-use-vma__is_fixed_mapping +++ a/tools/testing/vma/include/dup.h @@ -1676,6 +1676,20 @@ static inline bool vma_is_mm_managed(con return vma_flags_is_mm_managed(&vma->flags); } +static inline bool vma_flags_is_fixed_mapping(const vma_flags_t *flags) +{ + /* + * VMA_PFNMAP_BIT should imply VMA_DONTEXPAND_BIT, but some callers set + * only the former. + */ + return vma_flags_test_any(flags, VMA_PFNMAP_BIT, VMA_DONTEXPAND_BIT); +} + +static inline bool vma_is_fixed_mapping(const struct vm_area_struct *vma) +{ + return vma_flags_is_fixed_mapping(&vma->flags); +} + static inline bool vma_flags_can_merge(const vma_flags_t *flags) { /* @@ -1691,7 +1705,7 @@ static inline bool vma_flags_can_merge(c if (!vma_flags_is_mm_managed(flags)) return false; /* VMA explicitly marked as being unmergeable. */ - if (vma_flags_test(flags, VMA_DONTEXPAND_BIT)) + if (vma_flags_is_fixed_mapping(flags)) return false; return true; _ Patches currently in -mm which might be from ljs@kernel.org are 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-madvise-update-is_valid_guard_vma-to-use-vma_can_merge.patch mm-vma-introduce-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