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 021E5556BB7 for ; Tue, 8 Sep 2026 19:50:19 +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=1788897021; cv=none; b=u54r3uwDHLN4g0J8GkPHprp3d7F8qzs5773VbxawmPXly6j/zZkiIICaqc6TlhK/b9+VPZ/7o26BxAW0cnR0T6fGANknt97nR3Em84Rj/mzEsdiDUDLuv3EcmFlHOD3CmY+0nkPIqhqMkIJ4Ot/ryL0tuybdZasF+cSIuNcfO5o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788897021; c=relaxed/simple; bh=QEo22RL+aJVctC3qm3EgHO1XzyaCNKcfKe4NG/mWX30=; h=Date:To:From:Subject:Message-Id; b=NF/LAwBOyRkO+xrII4rjlZbzOMME3ccr0aCqjwevGj3NTzuoSCop4+HLEQ6iyX+62aj40JxTYQkA1PYsC6ZJmDmUtxHcnVisbnf6MlHbyNtzLuT4sXTrfiHtrKwWysNtNfJTxGD5tGqaQFRkmJLzJJxiqMAtb3cfQUo8ctnNCOI= 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=jlOELWJY; 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="jlOELWJY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5CDFB1F00A3D; Tue, 8 Sep 2026 19:50:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1788897019; bh=nlKoI3nkvNLVXamJpqxzW/DAjHqABT6Mf+IUqnJUt5I=; h=Date:To:From:Subject; b=jlOELWJYFKdAoYYJU3EobBV00sVnKrFgALODeTrFdGuv6rMQGrd4sP+eIKzf1Ew1S hB6GHKgEDQxw7/UZsOJLamCyN8A9Bhj1CjPHoFSdHDt6gQ2QIsgsMDDd97cHM9ItiZ 7T6HmFyie1Qdo8E6gaduestljvUx8X6FmO9glw4o= Date: Tue, 08 Sep 2026 12:50:18 -0700 To: mm-commits@vger.kernel.org,kas@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: + selftests-mm-add-folio-order-check-for-address-ranges.patch added to mm-new branch Message-Id: <20260908195019.5CDFB1F00A3D@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: selftests/mm: add folio-order check for address ranges has been added to the -mm mm-new branch. Its filename is selftests-mm-add-folio-order-check-for-address-ranges.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-mm-add-folio-order-check-for-address-ranges.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. The mm-new branch of mm.git is not included in linux-next If a few days of testing in mm-new is successful, the patch will me moved into mm.git's mm-unstable branch, which is included in linux-next 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: "Kiryl Shutsemau (Meta)" Subject: selftests/mm: add folio-order check for address ranges Date: Tue, 8 Sep 2026 13:50:54 +0100 An mTHP collapse test needs to know that a range is backed by folios of the target order, and that they sit where a collapse would put them. Nothing answers that today: is_backed_by_folio() classifies the folio behind a single page, and check_huge_anon() reads smaps AnonHugePages, which only accounts PMD mappings. Add is_range_backed_by_order(). It requires every folio-sized, folio- aligned part of the range to map one folio of that order, head to tail, with the head at the start of the part. A part backed by two smaller folios fails, and so does a folio mapped off its natural alignment. The mTHP cases need both to tell a collapsed range from the one beside it. Assisted-by: LLM Link: https://lore.kernel.org/20260908125105.1510704-9-kirill@shutemov.name Signed-off-by: Kiryl Shutsemau (Meta) Reviewed-by: Mike Rapoport (Microsoft) Tested-by: Muhammad Usama Anjum Cc: Alexander Gordeev Cc: Baolin Wang Cc: Barry Song Cc: David Hildenbrand Cc: Dev Jain Cc: Hugh Dickins Cc: Jason Gunthorpe Cc: Lance Yang Cc: Leon Romanovsky Cc: Liam R. Howlett Cc: Lorenzo Stoakes (ARM) Cc: Michal Hocko Cc: Ryan Roberts Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Usama Arif Cc: Vlastimil Babka Cc: Zi Yan Signed-off-by: Andrew Morton --- tools/testing/selftests/mm/vm_util.c | 47 +++++++++++++++++++++++++ tools/testing/selftests/mm/vm_util.h | 2 + 2 files changed, 49 insertions(+) --- a/tools/testing/selftests/mm/vm_util.c~selftests-mm-add-folio-order-check-for-address-ranges +++ a/tools/testing/selftests/mm/vm_util.c @@ -552,6 +552,53 @@ fail: return false; } +/** + * is_range_backed_by_order() - check that a range is backed by @order folios + * @start: start of the range, a multiple of the folio size + * @len: length of the range in bytes, a multiple of the folio size + * @order: the folio order to check for + * @pagemap_fd: open /proc//pagemap of the range's owner + * @kpageflags_fd: open /proc/kpageflags + * + * Every folio-sized, folio-aligned part of the range must map one folio of + * @order, head to tail, with the head at the start of the part. A part + * backed by several smaller folios fails, and so does a folio mapped off + * its natural alignment. + * + * Returns: true if the whole range is backed that way, false otherwise. + */ +bool is_range_backed_by_order(char *start, size_t len, int order, + int pagemap_fd, int kpageflags_fd) +{ + const unsigned long nr_pages = 1UL << order; + const size_t folio_size = nr_pages * psize(); + char *vaddr; + + if ((uintptr_t)start % folio_size || len % folio_size) + return false; + + for (vaddr = start; vaddr < start + len; vaddr += folio_size) { + const unsigned long pfn = pagemap_get_pfn(pagemap_fd, vaddr); + unsigned long i; + + /* Not present, or a tail page */ + if (pfn == -1UL || pfn % nr_pages) + return false; + + for (i = 1; i < nr_pages; i++) { + char *page = vaddr + i * psize(); + + if (pagemap_get_pfn(pagemap_fd, page) != pfn + i) + return false; + } + + if (!is_backed_by_folio(vaddr, order, pagemap_fd, kpageflags_fd)) + return false; + } + + return true; +} + /* If `ioctls' non-NULL, the allowed ioctls will be returned into the var */ int uffd_register_with_ioctls(int uffd, void *addr, uint64_t len, bool miss, bool wp, bool minor, uint64_t *ioctls) --- a/tools/testing/selftests/mm/vm_util.h~selftests-mm-add-folio-order-check-for-address-ranges +++ a/tools/testing/selftests/mm/vm_util.h @@ -101,6 +101,8 @@ int gather_folio_orders(char *vaddr_star int pagemap_fd, int kpageflags_fd, int orders[], int nr_orders); bool is_backed_by_folio(char *vaddr, int order, int pagemap_fd, int kpageflags_fd); +bool is_range_backed_by_order(char *start, size_t len, int order, + int pagemap_fd, int kpageflags_fd); int uffd_register(int uffd, void *addr, uint64_t len, bool miss, bool wp, bool minor); _ Patches currently in -mm which might be from kas@kernel.org are mm-huge_memory-do-not-touch-frozen-folios-in-deferred_split_isolate.patch mm-huge_memory-dequeue-the-deferred-split-after-the-split-freeze.patch selftests-mm-raise-the-khugepaged-test-case-cap.patch selftests-mm-skip-collapse_compound_extreme-where-the-pmd-is-too-large.patch selftests-mm-scale-khugepageds-collapse-wait-with-the-pmd-size.patch selftests-mm-skip-khugepaged-page-cache-cases-without-a-pmd-folio.patch selftests-mm-make-the-swap-cases-swapout-reliable.patch selftests-mm-stop-khugepaged-during-the-madv_collapse-cases.patch selftests-mm-move-is_backed_by_folio-into-vm_util.patch selftests-mm-add-folio-order-check-for-address-ranges.patch selftests-mm-add-folio-order-detection-self-check.patch selftests-mm-add-khugepaged-completion-barrier-helper.patch selftests-mm-add-order-parameterized-khugepaged-collapse-cases.patch selftests-mm-parameterize-the-mixed-source-collapse-case-by-source-order.patch selftests-mm-cover-a-shared-source-collapse-write-race.patch selftests-mm-run-every-supported-collapse-order-by-default.patch selftests-mm-check-that-one-khugepaged-pass-collapses-one-window.patch selftests-mm-add-khugepaged-race-harness.patch selftests-mm-race-the-collapse-of-windows-with-holes.patch selftests-mm-add-memory-pressure-threads-to-the-khugepaged-race-harness.patch selftests-mm-zap-whole-pte-tables-in-the-khugepaged-race-harness.patch