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 BE8AD48E0FA for ; Tue, 8 Sep 2026 19:50:04 +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=1788897006; cv=none; b=Yl3a/u6/wMIJFgQ3ofml+SqSEBqyWxwuJ/LDT1Z+sANV1h2yBFEF2QBYmoLGyCpeZcba+rjeHZZhwu/EEM6V+5uUWMnk3hy7cOJRxtxkWllzKmdHFF+uw/6cRNeciD0wxnuriCmhjA3ph2ACCCbPwKtQGHD/F1BQScVAydwJV2k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788897006; c=relaxed/simple; bh=jiHhx4HhoUQiiCVdemJiO9392qLSkt3VKzFXMtfifDg=; h=Date:To:From:Subject:Message-Id; b=gIhPtuvKoHVDY+v2dZoYOVEO+0Gh9GMlfSmey5qV6QBYCbaOBD4Prb0+dZAweKR3MpDRL79dh5Q6Xw/s7wH92QjyJ6C8iN0kiZvXJvC/sck7Po8BsNVo7SSNqU797oEOWgeKBQj7QA3A8TdPO5BstXbw4h+VRKMz58vff+hmKEY= 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=Xo0GgQhO; 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="Xo0GgQhO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7CA6C1F00A3A; Tue, 8 Sep 2026 19:50:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1788897004; bh=pXGXs7ZFuHxpzefcoMocNghGo7GAdgHRQBdmQGNTot0=; h=Date:To:From:Subject; b=Xo0GgQhOvpPyAVoKDcNbxwacUNfTcgku6T4Z3cEM7wD2rybw3fy22iPklSpOwFMYR IHF+Zj/LCI2aV1KDPI95/jx8m3AXIbsGBfj1rVhPo8JxENjJ661tvviBCB4JsGnpbg TAulnbftKJBoCdjm8SwQ8FkjWSEqN9luD6GK5JV0= Date: Tue, 08 Sep 2026 12:50:04 -0700 To: mm-commits@vger.kernel.org,kas@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: + selftests-mm-skip-collapse_compound_extreme-where-the-pmd-is-too-large.patch added to mm-new branch Message-Id: <20260908195004.7CA6C1F00A3A@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: skip collapse_compound_extreme() where the PMD is too large has been added to the -mm mm-new branch. Its filename is selftests-mm-skip-collapse_compound_extreme-where-the-pmd-is-too-large.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-mm-skip-collapse_compound_extreme-where-the-pmd-is-too-large.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: skip collapse_compound_extreme() where the PMD is too large Date: Tue, 8 Sep 2026 13:50:48 +0100 collapse_compound_extreme() builds a PTE table full of distinct PTE-mapped compound pages by cycling hpage_pmd_nr fault-time THPs through mremap. It therefore needs hpage_pmd_nr PMD-order allocations in a row. That is fine at a 2M PMD (4K base pages) or a 32M one (16K). A 512M PMD -- arm64 with 64K base pages -- makes each of those an order-13 allocation, which the allocator cannot reliably hand out even once, let alone 8192 times. The failure is not a quiet one: the case calls ksft_exit_fail_msg(), so the whole binary stops and every case after it is lost. Skip the case where the PMD is larger than 32M. The MADV_COLLAPSE cases still cover PMD-order collapse on those configurations, and 4K and 16K PMDs are unaffected. Assisted-by: LLM Link: https://lore.kernel.org/20260908125105.1510704-3-kirill@shutemov.name Signed-off-by: Kiryl Shutsemau (Meta) Acked-by: Lorenzo Stoakes (ARM) 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: 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/khugepaged.c | 10 ++++++++++ 1 file changed, 10 insertions(+) --- a/tools/testing/selftests/mm/khugepaged.c~selftests-mm-skip-collapse_compound_extreme-where-the-pmd-is-too-large +++ a/tools/testing/selftests/mm/khugepaged.c @@ -940,6 +940,16 @@ static void collapse_compound_extreme(st void *p; int i; + /* + * This needs hpage_pmd_nr PMD-order allocations in a row, which the + * allocator will not supply if the PMD is very large. + */ + if (hpage_pmd_size > (32UL << 20)) { + ksft_test_result_skip("%s: PMD too large for fault-time THP construction\n", + __func__); + return; + } + p = ops->setup_area(1); ksft_print_msg("Construct PTE page table full of different PTE-mapped compound pages\n"); for (i = 0; i < hpage_pmd_nr; i++) { _ 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