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 33CD049B5DC for ; Thu, 10 Sep 2026 21:56:13 +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=1789077374; cv=none; b=n4Aqfps3rNIi/6bBk5xDzUd/OmntrhPvkpBMrqlcovGnAmB40iyHUjrJvKMu091lAyzBcsq6aS+xptQ/QQsSUE+Y9C6L6eQB1+zb/p/8boDO60EjI/BOyuRqFbjm+HuSHbKjK61Eifex/RwZ6dLeRXliQWMyTNNtmovo2CGDHNg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789077374; c=relaxed/simple; bh=c48dGXxXC9bmdx+B7V1QCfMAoAw1tbdVqSPDaFv4lao=; h=Date:To:From:Subject:Message-Id; b=fNTUoxp2H9rZhLFTy7wEOOyEwwrZLm7RC2z6S/cPglA5E9XBjRbgyOvdMo+JM4xB22hBl1Zs3l3+shQ1o864mjeP7Ui149jTzpE6suIxUyBl+QB7PBHrwN/rdDbo3Mzhl8eHYqQCzetAthRPMpSTyL/FEDiwyw71QGnfqALch34= 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=ddIgUS2h; 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="ddIgUS2h" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C272C1F000FF; Thu, 10 Sep 2026 21:56:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1789077372; bh=n0sw02qeAw6su+qa7PAXfO/SH4dN8d3wOsxsRtUzY1I=; h=Date:To:From:Subject; b=ddIgUS2h9eeCtzaFvQXAIgPDXCMbmg2n0Y/P92u6PewRH2eCiEiuEMpv1WwR33LpF YV/8S/A/dil57Gx23kAgSbQq362U+kE4lMxzMbmPZESP+FHK7AslccFAn+pMKdh4AP /KsERyek1vcTscdK4KaudSxmE5cFjKNIvZJEbuuo= Date: Thu, 10 Sep 2026 14:56:12 -0700 To: mm-commits@vger.kernel.org,ziy@nvidia.com,vbabka@kernel.org,ryan.roberts@arm.com,ljs@kernel.org,liam@infradead.org,lance.yang@linux.dev,jannh@google.com,dev.jain@arm.com,david@kernel.org,baolin.wang@linux.alibaba.com,baohua@kernel.org,kas@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-collapse-work-out-the-orders-a-vma-allows-once-per-vma.patch added to mm-new branch Message-Id: <20260910215612.C272C1F000FF@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm/collapse: work out the orders a VMA allows once per VMA has been added to the -mm mm-new branch. Its filename is mm-collapse-work-out-the-orders-a-vma-allows-once-per-vma.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-collapse-work-out-the-orders-a-vma-allows-once-per-vma.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: mm/collapse: work out the orders a VMA allows once per VMA Date: Thu, 10 Sep 2026 13:02:30 +0100 The scan asked collapse_possible_orders() for every PTE table, for an answer that is a property of the VMA. Both callers walk a VMA a table at a time, so let them work it out once and pass the mask in. It is only good while the lock that produced it is held, so madvise_collapse() takes it again after every collapse. The mask is then sampled once per VMA rather than once per table. A thp enabled knob written during a walk takes effect one VMA later, and cannot widen a collapse: hugepage_vma_revalidate() tests the order again under the lock the collapse retakes. Assisted-by: LLM Link: https://lore.kernel.org/20260910120238.2529819-11-kirill@shutemov.name Signed-off-by: Kiryl Shutsemau (Meta) Cc: Baolin Wang Cc: Barry Song Cc: David Hildenbrand Cc: Dev Jain Cc: Jann Horn Cc: Lance Yang Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Ryan Roberts Cc: Vlastimil Babka Cc: Zi Yan Signed-off-by: Andrew Morton --- mm/khugepaged.c | 32 ++++++++++++++++++-------------- 1 file changed, 18 insertions(+), 14 deletions(-) --- a/mm/khugepaged.c~mm-collapse-work-out-the-orders-a-vma-allows-once-per-vma +++ a/mm/khugepaged.c @@ -1551,12 +1551,12 @@ done: } static enum scan_result collapse_scan_anon_pmd(struct vm_area_struct *vma, - unsigned long start_addr, struct collapse_control *cc) + unsigned long start_addr, struct collapse_control *cc, + unsigned long enabled_orders) { const unsigned int max_ptes_shared = collapse_max_ptes_shared(cc, HPAGE_PMD_ORDER); const unsigned int max_ptes_swap = collapse_max_ptes_swap(cc, HPAGE_PMD_ORDER); unsigned int max_ptes_none = collapse_max_ptes_none(cc, vma, HPAGE_PMD_ORDER); - enum tva_type tva_flags = cc->policy.tva_type; struct mm_struct *mm = vma->vm_mm; pmd_t *pmd; pte_t *pte, *_pte, pteval; @@ -1567,7 +1567,6 @@ static enum scan_result collapse_scan_an struct folio *folio = NULL; unsigned long failed_pfn = -1; unsigned long addr; - unsigned long enabled_orders; spinlock_t *ptl; int node = NUMA_NO_NODE, unmapped = 0; @@ -1581,8 +1580,6 @@ static enum scan_result collapse_scan_an collapse_scan_reset(cc); - enabled_orders = collapse_possible_orders(vma, vma->vm_flags, tva_flags); - /* * If PMD is the only enabled order, enforce max_ptes_none, otherwise * scan all pages to populate the bitmap for mTHP collapse. The bitmap @@ -2762,7 +2759,8 @@ static void collapse_control_release(str } static enum scan_result collapse_scan_pmd(struct vm_area_struct *vma, - unsigned long addr, struct collapse_control *cc) + unsigned long addr, struct collapse_control *cc, + unsigned long orders) { enum scan_result result; pgoff_t pgoff; @@ -2775,7 +2773,7 @@ static enum scan_result collapse_scan_pm } if (vma_is_anonymous(vma)) - return collapse_scan_anon_pmd(vma, addr, cc); + return collapse_scan_anon_pmd(vma, addr, cc, orders); pgoff = linear_page_index(vma, addr); result = collapse_scan_file(vma->vm_mm, addr, vma->vm_file, pgoff, cc); @@ -2896,15 +2894,17 @@ static void collapse_scan_mm_slot(unsign vma_iter_init(&vmi, mm, khugepaged_scan.address); for_each_vma(vmi, vma) { - unsigned long hstart, hend; + unsigned long hstart, hend, orders; cond_resched(); if (unlikely(collapse_test_exit_or_disable(mm))) { cc->progress++; break; } - if (!collapse_possible_orders(vma, vma->vm_flags, - TVA_KHUGEPAGED)) { + /* One mask for the whole VMA */ + orders = collapse_possible_orders(vma, vma->vm_flags, + cc->policy.tva_type); + if (!orders) { cc->progress++; continue; } @@ -2933,7 +2933,7 @@ static void collapse_scan_mm_slot(unsign /* move to next address */ khugepaged_scan.address += HPAGE_PMD_SIZE; - *result = collapse_scan_pmd(vma, addr, cc); + *result = collapse_scan_pmd(vma, addr, cc, orders); /* Nothing to collapse here, and the lock is still ours */ if (*result != SCAN_SUCCEED) { if (cc->progress >= progress_max) @@ -3217,14 +3217,16 @@ int madvise_collapse(struct vm_area_stru { struct collapse_control *cc; struct mm_struct *mm = vma->vm_mm; - unsigned long hstart, hend, addr; + unsigned long hstart, hend, addr, orders; enum scan_result last_fail = SCAN_FAIL; int thps = 0; BUG_ON(vma->vm_start > start); BUG_ON(vma->vm_end < end); - if (!collapse_possible_orders(vma, vma->vm_flags, TVA_FORCED_COLLAPSE)) + orders = collapse_possible_orders(vma, vma->vm_flags, + TVA_FORCED_COLLAPSE); + if (!orders) return -EINVAL; hstart = ALIGN(start, HPAGE_PMD_SIZE); @@ -3262,9 +3264,11 @@ int madvise_collapse(struct vm_area_stru } vma = found; hend = min(hend, vma->vm_end & HPAGE_PMD_MASK); + orders = collapse_possible_orders(vma, vma->vm_flags, + cc->policy.tva_type); } - result = collapse_scan_pmd(vma, addr, cc); + result = collapse_scan_pmd(vma, addr, cc, orders); /* Nothing to collapse here, and the lock is still ours */ if (result != SCAN_SUCCEED) goto tally; _ 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