From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 3EF583B38A2 for ; Mon, 11 May 2026 20:56:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778532964; cv=none; b=QLFb4Fy+tvkGKWIg9VDEwIKhyv73kImXlfgNOS6RzkRTXDRBqgSH1O1VX0sKd3tkVVQ5FM6/x1xwX8LOXNAU9pIwSABurnfXXNQAXhLc4GDzJBXHSggTNHxRt8sERgVOEAab4VvTdtTOeW4g5n9ydferXCX/2aZyz5P9DkAX9S8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778532964; c=relaxed/simple; bh=Yj5joXP0Un/7PD3LgyoZLH/txgHoA7zhynOFn2oFRC4=; h=Date:To:From:Subject:Message-Id; b=aFqr43X6EpydGzZwVFtbEUoDu3DQNRjZBoF8Ofkqv2Z48OJDfi7XNca83qzYuPtRwZ6eXFpF9M3d5bBuqXw89K/HGKZLSys0qLAGK+Dd5bXY1IWpofC3yCt+Fm7E993DW9rhinRGkSvkCV7QMfGcs1jaZWl43r6f8Jj75k3wtzE= 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=nPblgtRq; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="nPblgtRq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BA274C2BCB0; Mon, 11 May 2026 20:56:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1778532963; bh=Yj5joXP0Un/7PD3LgyoZLH/txgHoA7zhynOFn2oFRC4=; h=Date:To:From:Subject:From; b=nPblgtRqC1LscQm0gq5JhOGBVGrw9K1T/B5obUjzHzJs6dD9wXUUzXecW+aiUT6ul Vm1QmWX8iMjUwPZ5h9aXh4q7Ymc1FXw0eqWpcNg+tvqtZ0x3HR6twZmjGgh8IhPKnF v7Zv0qANpXbfO3UgVtLvSg5wBYo3QGIWZMQOVls0= Date: Mon, 11 May 2026 13:56:03 -0700 To: mm-commits@vger.kernel.org,npache@redhat.com,akpm@linux-foundation.org From: Andrew Morton Subject: [to-be-updated] mm-khugepaged-skip-collapsing-mthp-to-smaller-orders.patch removed from -mm tree Message-Id: <20260511205603.BA274C2BCB0@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/khugepaged: skip collapsing mTHP to smaller orders has been removed from the -mm tree. Its filename was mm-khugepaged-skip-collapsing-mthp-to-smaller-orders.patch This patch was dropped because an updated version will be issued ------------------------------------------------------ From: Nico Pache Subject: mm/khugepaged: skip collapsing mTHP to smaller orders Date: Sun, 19 Apr 2026 12:57:43 -0600 khugepaged may try to collapse a mTHP to a smaller mTHP, resulting in some pages being unmapped. Skip these cases until we have a way to check if its ok to collapse to a smaller mTHP size (like in the case of a partially mapped folio). This check is also not done during the scan phase as the current collapse order is unknown at that time. This patch is inspired by Dev Jain's work on khugepaged mTHP support [1]. Link: https://lore.kernel.org/20260419185750.260784-7-npache@redhat.com Link: https://lore.kernel.org/lkml/20241216165105.56185-11-dev.jain@arm.com/ [1] Co-developed-by: Dev Jain Signed-off-by: Dev Jain Signed-off-by: Nico Pache Reviewed-by: Lorenzo Stoakes Reviewed-by: Baolin Wang Acked-by: Usama Arif Cc: Alistair Popple Cc: Andrea Arcangeli Cc: Anshuman Khandual Cc: Bagas Sanjaya Cc: Barry Song Cc: Brendan Jackman Cc: Byungchul Park Cc: Catalin Marinas Cc: David Hildenbrand (Arm) Cc: David Rientjes Cc: Gregory Price Cc: "Huang, Ying" Cc: Hugh Dickins Cc: Jan Kara Cc: Jann Horn Cc: Johannes Weiner Cc: Jonathan Corbet Cc: Joshua Hahn Cc: Kefeng Wang Cc: Lance Yang Cc: Liam Howlett Cc: "Masami Hiramatsu (Google)" Cc: Mathieu Desnoyers Cc: Matthew Brost Cc: Matthew Wilcox (Oracle) Cc: Michal Hocko Cc: Mike Rapoport Cc: Nanyong Sun Cc: Pedro Falcato Cc: Peter Xu Cc: Rafael Aquini Cc: Rakie Kim Cc: Randy Dunlap Cc: Ryan Roberts Cc: Shivank Garg Cc: Steven Rostedt Cc: Suren Baghdasaryan Cc: Takashi Iwai (SUSE) Cc: Thomas Hellström Cc: Vishal Moola (Oracle) Cc: Vlastimil Babka Cc: Wei Yang Cc: Will Deacon Cc: Yang Shi Cc: Zach O'Keefe Cc: Zi Yan Signed-off-by: Andrew Morton --- mm/khugepaged.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/mm/khugepaged.c~mm-khugepaged-skip-collapsing-mthp-to-smaller-orders +++ a/mm/khugepaged.c @@ -686,6 +686,14 @@ static enum scan_result __collapse_huge_ goto out; } } + /* + * TODO: In some cases of partially-mapped folios, we'd actually + * want to collapse. + */ + if (!is_pmd_order(order) && folio_order(folio) >= order) { + result = SCAN_PTE_MAPPED_HUGEPAGE; + goto out; + } if (folio_test_large(folio)) { struct folio *f; _ Patches currently in -mm which might be from npache@redhat.com are mm-khugepaged-add-per-order-mthp-collapse-failure-statistics.patch mm-khugepaged-improve-tracepoints-for-mthp-orders.patch mm-khugepaged-introduce-collapse_allowable_orders-helper-function.patch mm-khugepaged-introduce-mthp-collapse-support.patch mm-khugepaged-avoid-unnecessary-mthp-collapse-attempts.patch documentation-mm-update-the-admin-guide-for-mthp-collapse.patch