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 A09D43B5821 for ; Mon, 11 May 2026 20:55:58 +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=1778532958; cv=none; b=f5U7vPWXI6cs86rZL2OZyruzJF0CLBKI44p/9ac3+v2IZZr/hpwMtAFFquY/YkTnBTJIXiSevim6Lk0U+VT5x+rRnuWK0/vqP+dFcKWupTeBGuhs3frTE6NtvaH6LOwRdLJMl/Dgoefd5+FEXGITOKJEAi7u7KdWDMg7/Fhp4Gs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778532958; c=relaxed/simple; bh=uyCe9ISj7t+7I2i3z7aCs9iLZSxPF5aRwz2FpBmjHP0=; h=Date:To:From:Subject:Message-Id; b=h00XZvgQ4Lpz9nKrJO71g1DcbjofyuFdhz2chWrWHVD45vszfuFd6su+tD0wMWMyJZHpO+yDcYE74Eel3E2MZeRPYHV9tD6xDZm9btwq/mB+95nNx1lKSjyk0Xmyp+fENw5xzxZaTjarC4ojV0ZoGGtbIBV39oIva/d0ol2Km9E= 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=1YzY/lbG; 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="1YzY/lbG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 373B4C2BCF5; Mon, 11 May 2026 20:55:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1778532958; bh=uyCe9ISj7t+7I2i3z7aCs9iLZSxPF5aRwz2FpBmjHP0=; h=Date:To:From:Subject:From; b=1YzY/lbGaMsKzeJeGmOROeE1CG4o/wdybCZ4CfUNdQuZng/vu0BlMeZxZjJLXlsgD FNSM/cHwPAyAfxxwRb/5/Nd2idzcBtyTcnSWz6hiuKXp5lqrDkmtykup5dKoqtePey Tv+wkihOxAm89CcxSf4sPxuptJkwa7mbzjVI0NLU= Date: Mon, 11 May 2026 13:55:57 -0700 To: mm-commits@vger.kernel.org,npache@redhat.com,akpm@linux-foundation.org From: Andrew Morton Subject: [to-be-updated] mm-khugepaged-rework-max_ptes_-handling-with-helper-functions.patch removed from -mm tree Message-Id: <20260511205558.373B4C2BCF5@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: rework max_ptes_* handling with helper functions has been removed from the -mm tree. Its filename was mm-khugepaged-rework-max_ptes_-handling-with-helper-functions.patch This patch was dropped because an updated version will be issued ------------------------------------------------------ From: Nico Pache Subject: mm/khugepaged: rework max_ptes_* handling with helper functions Date: Sun, 19 Apr 2026 12:57:40 -0600 The following cleanup reworks all the max_ptes_* handling into helper functions. This increases the code readability and will later be used to implement the mTHP handling of these variables. With these changes we abstract all the madvise_collapse() special casing (dont respect the sysctls) away from the functions that utilize them. And will later in this series to cleanly restrict mTHP collapses behaviors. Link: https://lore.kernel.org/20260419185750.260784-4-npache@redhat.com Signed-off-by: Nico Pache Suggested-by: David Hildenbrand Acked-by: Usama Arif Cc: Alistair Popple Cc: Andrea Arcangeli Cc: Anshuman Khandual Cc: Bagas Sanjaya Cc: Baolin Wang Cc: Barry Song Cc: Brendan Jackman Cc: Byungchul Park Cc: Catalin Marinas Cc: David Rientjes Cc: Dev Jain 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: Lorenzo Stoakes 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 | 114 +++++++++++++++++++++++++++++++--------------- 1 file changed, 78 insertions(+), 36 deletions(-) --- a/mm/khugepaged.c~mm-khugepaged-rework-max_ptes_-handling-with-helper-functions +++ a/mm/khugepaged.c @@ -348,6 +348,58 @@ static bool pte_none_or_zero(pte_t pte) return pte_present(pte) && is_zero_pfn(pte_pfn(pte)); } +/** + * collapse_max_ptes_none - Calculate maximum allowed empty PTEs for collapse + * @cc: The collapse control struct + * @vma: The vma to check for userfaultfd + * + * If we are not in khugepaged mode use HPAGE_PMD_NR to allow any + * empty page. + * + * Return: Maximum number of empty PTEs allowed for the collapse operation + */ +static unsigned int collapse_max_ptes_none(struct collapse_control *cc, + struct vm_area_struct *vma) +{ + if (vma && userfaultfd_armed(vma)) + return 0; + if (!cc->is_khugepaged) + return HPAGE_PMD_NR; + return khugepaged_max_ptes_none; +} + +/** + * collapse_max_ptes_shared - Calculate maximum allowed shared PTEs for collapse + * @cc: The collapse control struct + * + * If we are not in khugepaged mode use HPAGE_PMD_NR to allow any + * shared page. + * + * Return: Maximum number of shared PTEs allowed for the collapse operation + */ +static unsigned int collapse_max_ptes_shared(struct collapse_control *cc) +{ + if (!cc->is_khugepaged) + return HPAGE_PMD_NR; + return khugepaged_max_ptes_shared; +} + +/** + * collapse_max_ptes_swap - Calculate maximum allowed swap PTEs for collapse + * @cc: The collapse control struct + * + * If we are not in khugepaged mode use HPAGE_PMD_NR to allow any + * swap page. + * + * Return: Maximum number of swap PTEs allowed for the collapse operation + */ +static unsigned int collapse_max_ptes_swap(struct collapse_control *cc) +{ + if (!cc->is_khugepaged) + return HPAGE_PMD_NR; + return khugepaged_max_ptes_swap; +} + int hugepage_madvise(struct vm_area_struct *vma, vm_flags_t *vm_flags, int advice) { @@ -546,21 +598,19 @@ static enum scan_result __collapse_huge_ pte_t *_pte; int none_or_zero = 0, shared = 0, referenced = 0; enum scan_result result = SCAN_FAIL; + unsigned int max_ptes_none = collapse_max_ptes_none(cc, vma); + unsigned int max_ptes_shared = collapse_max_ptes_shared(cc); for (_pte = pte; _pte < pte + HPAGE_PMD_NR; _pte++, addr += PAGE_SIZE) { pte_t pteval = ptep_get(_pte); if (pte_none_or_zero(pteval)) { - ++none_or_zero; - if (!userfaultfd_armed(vma) && - (!cc->is_khugepaged || - none_or_zero <= khugepaged_max_ptes_none)) { - continue; - } else { + if (++none_or_zero > max_ptes_none) { result = SCAN_EXCEED_NONE_PTE; count_vm_event(THP_SCAN_EXCEED_NONE_PTE); goto out; } + continue; } if (!pte_present(pteval)) { result = SCAN_PTE_NON_PRESENT; @@ -591,9 +641,7 @@ static enum scan_result __collapse_huge_ /* See collapse_scan_pmd(). */ if (folio_maybe_mapped_shared(folio)) { - ++shared; - if (cc->is_khugepaged && - shared > khugepaged_max_ptes_shared) { + if (++shared > max_ptes_shared) { result = SCAN_EXCEED_SHARED_PTE; count_vm_event(THP_SCAN_EXCEED_SHARED_PTE); goto out; @@ -1270,6 +1318,9 @@ static enum scan_result collapse_scan_pm unsigned long addr; spinlock_t *ptl; int node = NUMA_NO_NODE, unmapped = 0; + unsigned int max_ptes_none = collapse_max_ptes_none(cc, vma); + unsigned int max_ptes_shared = collapse_max_ptes_shared(cc); + unsigned int max_ptes_swap = collapse_max_ptes_swap(cc); VM_BUG_ON(start_addr & ~HPAGE_PMD_MASK); @@ -1294,36 +1345,29 @@ static enum scan_result collapse_scan_pm pte_t pteval = ptep_get(_pte); if (pte_none_or_zero(pteval)) { - ++none_or_zero; - if (!userfaultfd_armed(vma) && - (!cc->is_khugepaged || - none_or_zero <= khugepaged_max_ptes_none)) { - continue; - } else { + if (++none_or_zero > max_ptes_none) { result = SCAN_EXCEED_NONE_PTE; count_vm_event(THP_SCAN_EXCEED_NONE_PTE); goto out_unmap; } + continue; } if (!pte_present(pteval)) { - ++unmapped; - if (!cc->is_khugepaged || - unmapped <= khugepaged_max_ptes_swap) { - /* - * Always be strict with uffd-wp - * enabled swap entries. Please see - * comment below for pte_uffd_wp(). - */ - if (pte_swp_uffd_wp_any(pteval)) { - result = SCAN_PTE_UFFD_WP; - goto out_unmap; - } - continue; - } else { + if (++unmapped > max_ptes_swap) { result = SCAN_EXCEED_SWAP_PTE; count_vm_event(THP_SCAN_EXCEED_SWAP_PTE); goto out_unmap; } + /* + * Always be strict with uffd-wp + * enabled swap entries. Please see + * comment below for pte_uffd_wp(). + */ + if (pte_swp_uffd_wp_any(pteval)) { + result = SCAN_PTE_UFFD_WP; + goto out_unmap; + } + continue; } if (pte_uffd_wp(pteval)) { /* @@ -1366,9 +1410,7 @@ static enum scan_result collapse_scan_pm * is shared. */ if (folio_maybe_mapped_shared(folio)) { - ++shared; - if (cc->is_khugepaged && - shared > khugepaged_max_ptes_shared) { + if (++shared > max_ptes_shared) { result = SCAN_EXCEED_SHARED_PTE; count_vm_event(THP_SCAN_EXCEED_SHARED_PTE); goto out_unmap; @@ -2329,6 +2371,8 @@ static enum scan_result collapse_scan_fi int present, swap; int node = NUMA_NO_NODE; enum scan_result result = SCAN_SUCCEED; + unsigned int max_ptes_none = collapse_max_ptes_none(cc, NULL); + unsigned int max_ptes_swap = collapse_max_ptes_swap(cc); present = 0; swap = 0; @@ -2341,8 +2385,7 @@ static enum scan_result collapse_scan_fi if (xa_is_value(folio)) { swap += 1 << xas_get_order(&xas); - if (cc->is_khugepaged && - swap > khugepaged_max_ptes_swap) { + if (swap > max_ptes_swap) { result = SCAN_EXCEED_SWAP_PTE; count_vm_event(THP_SCAN_EXCEED_SWAP_PTE); break; @@ -2413,8 +2456,7 @@ static enum scan_result collapse_scan_fi cc->progress += HPAGE_PMD_NR; if (result == SCAN_SUCCEED) { - if (cc->is_khugepaged && - present < HPAGE_PMD_NR - khugepaged_max_ptes_none) { + if (present < HPAGE_PMD_NR - max_ptes_none) { result = SCAN_EXCEED_NONE_PTE; count_vm_event(THP_SCAN_EXCEED_NONE_PTE); } else { _ Patches currently in -mm which might be from npache@redhat.com are mm-khugepaged-generalize-__collapse_huge_page_-for-mthp-support.patch mm-khugepaged-generalize-collapse_huge_page-for-mthp-collapse.patch mm-khugepaged-skip-collapsing-mthp-to-smaller-orders.patch 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