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 24CD13D88F2 for ; Sun, 20 Sep 2026 23:54:51 +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=1789948493; cv=none; b=iair2B3CnQycCc2lFZv7bXAk3rzJFW7YzZH1qgf2u5y3cYjkI62BJgEhTFdccS9twnrthZ/kUg+B6VNcLYl0uLjvgE57oepBj7OP575rhmkbOrn/j1nTzcit4UXvR/kfAFqyZuhJJrWig9VeaO3iUsjcwrYBD6GVqW/GokEjaYM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789948493; c=relaxed/simple; bh=f4VNvF8CVjZRjP3sdg/wSNv1/0PO4FNZr94tGB1cq/Q=; h=Date:To:From:Subject:Message-Id; b=bIO5rrIYjATClfkwOWSggyoChnbJVGomDB+rWleaykxHQpzwZBtyy2BuDQd53js5Ot2qTdcD4/6BF66eZO8ecENKb2lI1AIKaK4KAmFFYTuHcvTYztkMDxQkqwnUJ4/vuOxSctRmog5Y36wYLYC2D3L4OpShnbBwIfjUqHjpWJI= 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=bPYODMie; 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="bPYODMie" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AC5211F000FF; Sun, 20 Sep 2026 23:54:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1789948491; bh=1q0AzHzP4bubjrfLNdoasoceljaKHmgc+Z34r2iSl2A=; h=Date:To:From:Subject; b=bPYODMieULPw5ewsOYtfoQXo5dOe7X16c7jFmCRtw9+4wdQW5drK/Chlx6bOKv7gi PTZQbgCmfSdUfBDZdNqbZpF2h8g4qufK14DpuiI24317OXRpDm7aDyFLzsJj1NYTQl 1THqpF19kJSS1DdL2mJn2wM4gLr8lUk4b2UFvPnE= Date: Sun, 20 Sep 2026 16:54:51 -0700 To: mm-commits@vger.kernel.org,kas@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: + selftests-mm-scale-khugepageds-collapse-wait-with-the-pmd-size.patch added to mm-new branch Message-Id: <20260920235451.AC5211F000FF@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: scale khugepaged's collapse wait with the PMD size has been added to the -mm mm-new branch. Its filename is selftests-mm-scale-khugepageds-collapse-wait-with-the-pmd-size.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-mm-scale-khugepageds-collapse-wait-with-the-pmd-size.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: scale khugepaged's collapse wait with the PMD size Date: Sat, 19 Sep 2026 01:24:33 +0100 wait_for_scan() gives every case the same three seconds, whatever the huge page costs to build. collapse_full() asks for four of them: 8M at a 2M PMD, but 2G at a 512M PMD -- arm64 with 64K base pages. Three seconds is thin at that size, and the case has reported a failure for a collapse that was still going. The timeout is a ceiling on a poll loop, not a sleep: the loop stops as soon as ops->check_huge() sees the collapse, or as soon as full_scans has advanced by two. Raising it costs a passing case nothing. Across 80 runs of collapse_full() on arm64 with 64K pages the wait was half a second in 73 of them, with a tail to two seconds. Keep three seconds as the floor and add a second per 128M collapsed. A 2M PMD is unchanged, so x86-64 is too; a 512M PMD gets 19 seconds. On arm64 with 64K pages a passing ./khugepaged all:anon takes 49 seconds under TCG before and after this change. Assisted-by: LLM Link: https://lore.kernel.org/20260919002451.496763-4-kirill@shutemov.name Signed-off-by: Kiryl Shutsemau (Meta) Signed-off-by: Andrew Morton Acked-by: Lorenzo Stoakes (ARM) Reviewed-by: Mike Rapoport (Microsoft) 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/khugepaged.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/tools/testing/selftests/mm/khugepaged.c~selftests-mm-scale-khugepageds-collapse-wait-with-the-pmd-size +++ a/tools/testing/selftests/mm/khugepaged.c @@ -561,8 +561,11 @@ static bool wait_for_scan(const char *ms int nr_hpages, int collap_order, struct mem_ops *ops) { unsigned long hpage_size = page_size << collap_order; - int full_scans; - int timeout = 6; /* 3 seconds */ + unsigned long bytes = (unsigned long)nr_hpages * hpage_size; + int timeout, full_scans; + + /* Half-second ticks: three seconds floor, plus a second per 128M */ + timeout = 6 + 2 * (bytes / (128UL << 20)); /* Sanity check */ if (!ops->check_huge(p, len, 0, hpage_size)) _ 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