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 CDCF13D75A0 for ; Sun, 20 Sep 2026 23:55:05 +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=1789948507; cv=none; b=c3qtSfej/QIuKW6+tfjEQ216oaOek+NSmovPa7noSdnyGwuh9nyMvjiF3v7foyO+lszySTxEdgWl52kOqFxk8mpMSsle4QWY7MoqHbtDF9N8uTtRpIdsBlmWARuTySYPIvxIvyxKT9s/BH3SzeZ4sB3vEoyp1iW6IxUDpkpWcoc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789948507; c=relaxed/simple; bh=sl0epoZVRigpDO4JWYtHfK3v5we5TP8mVuR8YRyDK1I=; h=Date:To:From:Subject:Message-Id; b=U19GqAtFV01cyTqpEUa/ntK0GvHQ4Hg7KZyzSKN8OTPUKRqliRws2uWPaayIEzqRolKqfKRmeK9nszc7sqFenyZmOGmbZpLAQN8vtJ9kTQ9v0vLhJENFMFROQInpeDggCw+iDsEYL2582q0XpEqwljbWSVIE9obfuwSeG07M16s= 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=KnNZwhiN; 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="KnNZwhiN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 830B51F00893; Sun, 20 Sep 2026 23:55:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1789948505; bh=/fgKFNLyusDTPuFW9hRE7T0Ew1XY85Pj0SuPGx0Cxm0=; h=Date:To:From:Subject; b=KnNZwhiNAWocjQJjaKG+yi5zQhq97MsDSNfeTOrvXIZZoBJ5hysiN7dXh2+cjrIOW rDKfsJg6fMfc2tNRRaFKYnbxYHh8AYMQD6M+NYmmt659eOOs7eSnDPaSv7DFu5Sn2K O4REjWMi8zkIKPVZXcelFJQbRBAPM7Le9wGQ8mYI= Date: Sun, 20 Sep 2026 16:55:05 -0700 To: mm-commits@vger.kernel.org,kas@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: + selftests-mm-move-is_backed_by_folio-into-vm_util.patch added to mm-new branch Message-Id: <20260920235505.830B51F00893@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: move is_backed_by_folio() into vm_util has been added to the -mm mm-new branch. Its filename is selftests-mm-move-is_backed_by_folio-into-vm_util.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-mm-move-is_backed_by_folio-into-vm_util.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: move is_backed_by_folio() into vm_util Date: Sat, 19 Sep 2026 01:24:37 +0100 Checking that an address range is backed by a folio of a given order is useful to any test that builds or collapses large folios. mTHP collapse coverage in the khugepaged selftest needs exactly that. split_huge_page_test.c already has the building block: is_backed_by_folio() reads the compound head and tail flags from /proc/kpageflags to classify the folio behind a page. Move it into vm_util so other tests can use it. No functional change. Assisted-by: LLM Link: https://lore.kernel.org/20260919002451.496763-8-kirill@shutemov.name Signed-off-by: Kiryl Shutsemau (Meta) Signed-off-by: Andrew Morton Acked-by: Mike Rapoport (Microsoft) Acked-by: Lorenzo Stoakes (ARM) Reviewed-by: Baolin Wang Tested-by: Muhammad Usama Anjum Cc: Alexander Gordeev Cc: Barry Song Cc: "David Hildenbrand (arm)" Cc: Dev Jain Cc: Hugh Dickens Cc: Jason Gunthorpe Cc: kernel-team@meta.com Cc: Lance Yang Cc: Leon Romanovsky Cc: Liam Howlett Cc: Michal Hocko Cc: Nico Pache (Red Hat) Cc: Ryan Roberts Cc: Shuah Khan (Samsung OSG) Cc: Suren Baghdasaryan Cc: Usama Arif Cc: "Vlastimil Babka (SUSE)" Cc: Zi Yan --- tools/testing/selftests/mm/split_huge_page_test.c | 61 ------------ tools/testing/selftests/mm/vm_util.c | 61 ++++++++++++ tools/testing/selftests/mm/vm_util.h | 2 3 files changed, 63 insertions(+), 61 deletions(-) --- a/tools/testing/selftests/mm/split_huge_page_test.c~selftests-mm-move-is_backed_by_folio-into-vm_util +++ a/tools/testing/selftests/mm/split_huge_page_test.c @@ -41,67 +41,6 @@ const char *kpageflags_proc = "/proc/kpa int pagemap_fd; int kpageflags_fd; -static bool is_backed_by_folio(char *vaddr, int order, int pagemap_fd, - int kpageflags_fd) -{ - const uint64_t folio_head_flags = KPF_THP | KPF_COMPOUND_HEAD; - const uint64_t folio_tail_flags = KPF_THP | KPF_COMPOUND_TAIL; - const unsigned long nr_pages = 1UL << order; - unsigned long pfn_head; - uint64_t pfn_flags; - unsigned long pfn; - unsigned long i; - - pfn = pagemap_get_pfn(pagemap_fd, vaddr); - - /* non present page */ - if (pfn == -1UL) - return false; - - if (pageflags_get(pfn, kpageflags_fd, &pfn_flags)) - goto fail; - - /* check for order-0 pages */ - if (!order) { - if (pfn_flags & (folio_head_flags | folio_tail_flags)) - return false; - return true; - } - - /* non THP folio */ - if (!(pfn_flags & KPF_THP)) - return false; - - pfn_head = pfn & ~(nr_pages - 1); - - if (pageflags_get(pfn_head, kpageflags_fd, &pfn_flags)) - goto fail; - - /* head PFN has no compound_head flag set */ - if ((pfn_flags & folio_head_flags) != folio_head_flags) - return false; - - /* check all tail PFN flags */ - for (i = 1; i < nr_pages; i++) { - if (pageflags_get(pfn_head + i, kpageflags_fd, &pfn_flags)) - goto fail; - if ((pfn_flags & folio_tail_flags) != folio_tail_flags) - return false; - } - - /* - * check the PFN after this folio, but if its flags cannot be obtained, - * assume this folio has the expected order - */ - if (pageflags_get(pfn_head + nr_pages, kpageflags_fd, &pfn_flags)) - return true; - - /* If we find another tail page, then the folio is larger. */ - return (pfn_flags & folio_tail_flags) != folio_tail_flags; -fail: - ksft_exit_fail_msg("Failed to get folio info\n"); -} - static int check_after_split_folio_orders(char *vaddr_start, size_t len, int pagemap_fd, int kpageflags_fd, int orders[], int nr_orders) { --- a/tools/testing/selftests/mm/vm_util.c~selftests-mm-move-is_backed_by_folio-into-vm_util +++ a/tools/testing/selftests/mm/vm_util.c @@ -490,6 +490,67 @@ int pageflags_get(unsigned long pfn, int return 0; } +bool is_backed_by_folio(char *vaddr, int order, int pagemap_fd, + int kpageflags_fd) +{ + const uint64_t folio_head_flags = KPF_THP | KPF_COMPOUND_HEAD; + const uint64_t folio_tail_flags = KPF_THP | KPF_COMPOUND_TAIL; + const unsigned long nr_pages = 1UL << order; + unsigned long pfn_head; + uint64_t pfn_flags; + unsigned long pfn; + unsigned long i; + + pfn = pagemap_get_pfn(pagemap_fd, vaddr); + + /* non present page */ + if (pfn == -1UL) + return false; + + if (pageflags_get(pfn, kpageflags_fd, &pfn_flags)) + goto fail; + + /* check for order-0 pages */ + if (!order) { + if (pfn_flags & (folio_head_flags | folio_tail_flags)) + return false; + return true; + } + + /* non THP folio */ + if (!(pfn_flags & KPF_THP)) + return false; + + pfn_head = pfn & ~(nr_pages - 1); + + if (pageflags_get(pfn_head, kpageflags_fd, &pfn_flags)) + goto fail; + + /* head PFN has no compound_head flag set */ + if ((pfn_flags & folio_head_flags) != folio_head_flags) + return false; + + /* check all tail PFN flags */ + for (i = 1; i < nr_pages; i++) { + if (pageflags_get(pfn_head + i, kpageflags_fd, &pfn_flags)) + goto fail; + if ((pfn_flags & folio_tail_flags) != folio_tail_flags) + return false; + } + + /* + * check the PFN after this folio, but if its flags cannot be obtained, + * assume this folio has the expected order + */ + if (pageflags_get(pfn_head + nr_pages, kpageflags_fd, &pfn_flags)) + return true; + + /* If we find another tail page, then the folio is larger. */ + return (pfn_flags & folio_tail_flags) != folio_tail_flags; +fail: + ksft_exit_fail_msg("Failed to get folio info\n"); +} + /* 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-move-is_backed_by_folio-into-vm_util +++ a/tools/testing/selftests/mm/vm_util.h @@ -99,6 +99,8 @@ int64_t allocate_transhuge(void *ptr, in int pageflags_get(unsigned long pfn, int kpageflags_fd, uint64_t *flags); int gather_folio_orders(char *vaddr_start, size_t len, 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); 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 mm-huge_memory-add-folio_reset_partially_mapped.patch mm-khugepaged-drop-redundant-mm_struct-pin-in-madvise_collapse.patch mm-khugepaged-count-collapses-where-khugepaged-makes-them.patch mm-khugepaged-rename-mthp_present_ptes-bitmap-to-eligible_ptes.patch mm-collapse-add-collapseh-for-the-collapse-interface.patch mm-collapse-state-what-a-collapse-may-do-in-the-policy.patch mm-collapse-drop-the-collapse_possible-wrapper.patch mm-collapse-name-the-per-table-scan-reset-for-what-it-resets.patch mm-collapse-separate-scanning-a-pte-table-from-collapsing-it.patch mm-collapse-open-code-collapse_single_pmd-in-its-two-callers.patch mm-collapse-work-out-the-orders-a-vma-allows-once-per-vma.patch mm-collapse-declare-the-collapse-interface-in-collapseh.patch mm-collapse-implement-madv_collapse-in-madvisec.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