From nobody Wed Dec 17 14:54:35 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A9DBACDB47E for ; Wed, 18 Oct 2023 20:33:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232458AbjJRUd1 (ORCPT ); Wed, 18 Oct 2023 16:33:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53930 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231911AbjJRUdO (ORCPT ); Wed, 18 Oct 2023 16:33:14 -0400 Received: from mail-pl1-x62e.google.com (mail-pl1-x62e.google.com [IPv6:2607:f8b0:4864:20::62e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E6734115 for ; Wed, 18 Oct 2023 13:33:11 -0700 (PDT) Received: by mail-pl1-x62e.google.com with SMTP id d9443c01a7336-1ca74e77aecso606935ad.1 for ; Wed, 18 Oct 2023 13:33:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1697661191; x=1698265991; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=AcNlnHmZuXPr4rVPOwy7uUYyAYPeSLuYyJXFxeMfebs=; b=IOxHLuPUMNnOYZ0BYOAEsZwUbKBYATaTxCgnaTOKcUkgKI5TqyKoswj9MfHu9TzKlc mJcOHpLBnR0zXcjKExY26NhIZfqCm/CXr/rLYvfVdHIiOt4tXV3du3x8yntJUYUrYhrN QL/1nr2bNIyFScdthvE1RdO9XZR3g3UqK+TOvL+136/3rCmFLD8Yc9OMQC2tDaHvHhMW zFeGJyM42r0fFhyJcDE0P2aBh4iumaOyt4g8A/k+A8IQjkjtbdle7lbrl4aDeu/hDcJ5 oj7Q4n51T15ipLl6uqJMJNOBP+tGoaYAHTkRjhjT4uOtteaBq9UjQ870Af0X2hEXnPVa W1eg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697661191; x=1698265991; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=AcNlnHmZuXPr4rVPOwy7uUYyAYPeSLuYyJXFxeMfebs=; b=REFBmIADc9NEZhOs3xyOm9cKfMuLxWGYWu7nRf+TmJiC/TFFARCck58MK0IejIgrsP BHQLvOmLmKYx0g0184+yYoJYKIr65wL9rmcyvv2p1yNiWYDNhfOQUMkJAwIbD5/aHOAR hSq1wIOO77G26L3F4eYkuWvf6XWeSq2MtOWLppJUIj40BEOOcrVjRzIiwlv6jFZ4SYG9 cIDsfqBjwhpZy3Qex6/qSQVbsROlVKOv7Fh6aYYuFM/ui6UQYZ9jiGA1vGjGmeoKcYbz xXpLnjr8G0GZsxWd8TuLCVrrkPsFSC8qZro/7j2nv00XUwxNoe/2q3TLXspsVXKSjFeZ j1Wg== X-Gm-Message-State: AOJu0Yw6FklT5kTzuEQUojKuWTwP4L2c0TuvDxC0mwCDa5JhsgIbCvi3 Z0aMvqOKDwqqCgVDzRED+BM= X-Google-Smtp-Source: AGHT+IEf7Gnz9O9WMz3CQOd+A4MjLM6TTZK4jiZl9DPWEVFFAHxMsHTxdrbBpGMTCyZdudHzKKxBQw== X-Received: by 2002:a17:902:e5cb:b0:1c6:e1d:8be0 with SMTP id u11-20020a170902e5cb00b001c60e1d8be0mr677167plf.2.1697661191282; Wed, 18 Oct 2023 13:33:11 -0700 (PDT) Received: from fedora.. (c-73-170-51-167.hsd1.ca.comcast.net. [73.170.51.167]) by smtp.googlemail.com with ESMTPSA id w12-20020a170902d3cc00b001c61e628e9dsm354412plb.77.2023.10.18.13.33.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Oct 2023 13:33:10 -0700 (PDT) From: "Vishal Moola (Oracle)" To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, shy828301@gmail.com, "Vishal Moola (Oracle)" Subject: [PATCH v2 5/5] mm/khugepaged: Convert collapse_pte_mapped_thp() to use folios Date: Wed, 18 Oct 2023 13:32:13 -0700 Message-Id: <20231018203213.50224-6-vishal.moola@gmail.com> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20231018203213.50224-1-vishal.moola@gmail.com> References: <20231018203213.50224-1-vishal.moola@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" This removes 2 calls to compound_head() and helps convert khugepaged to use folios throughout. Previously, if the address passed to collapse_pte_mapped_thp() corresponded to a tail page, the scan would fail immediately. Using filemap_lock_folio() we can get the corresponding folio back and try to operate on the folio instead. Signed-off-by: Vishal Moola (Oracle) --- mm/khugepaged.c | 45 ++++++++++++++++++++------------------------- 1 file changed, 20 insertions(+), 25 deletions(-) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index d49aa22d99c9..94c1dd09a8a6 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1475,7 +1475,7 @@ int collapse_pte_mapped_thp(struct mm_struct *mm, uns= igned long addr, bool notified =3D false; unsigned long haddr =3D addr & HPAGE_PMD_MASK; struct vm_area_struct *vma =3D vma_lookup(mm, haddr); - struct page *hpage; + struct folio *folio; pte_t *start_pte, *pte; pmd_t *pmd, pgt_pmd; spinlock_t *pml =3D NULL, *ptl; @@ -1508,19 +1508,14 @@ int collapse_pte_mapped_thp(struct mm_struct *mm, u= nsigned long addr, if (userfaultfd_wp(vma)) return SCAN_PTE_UFFD_WP; =20 - hpage =3D find_lock_page(vma->vm_file->f_mapping, + folio =3D filemap_lock_folio(vma->vm_file->f_mapping, linear_page_index(vma, haddr)); - if (!hpage) + if (!folio) return SCAN_PAGE_NULL; =20 - if (!PageHead(hpage)) { - result =3D SCAN_FAIL; - goto drop_hpage; - } - - if (compound_order(hpage) !=3D HPAGE_PMD_ORDER) { + if (folio_order(folio) !=3D HPAGE_PMD_ORDER) { result =3D SCAN_PAGE_COMPOUND; - goto drop_hpage; + goto drop_folio; } =20 result =3D find_pmd_or_thp_or_none(mm, haddr, &pmd); @@ -1534,13 +1529,13 @@ int collapse_pte_mapped_thp(struct mm_struct *mm, u= nsigned long addr, */ goto maybe_install_pmd; default: - goto drop_hpage; + goto drop_folio; } =20 result =3D SCAN_FAIL; start_pte =3D pte_offset_map_lock(mm, pmd, haddr, &ptl); if (!start_pte) /* mmap_lock + page lock should prevent this */ - goto drop_hpage; + goto drop_folio; =20 /* step 1: check all mapped PTEs are to the right huge page */ for (i =3D 0, addr =3D haddr, pte =3D start_pte; @@ -1565,7 +1560,7 @@ int collapse_pte_mapped_thp(struct mm_struct *mm, uns= igned long addr, * Note that uprobe, debugger, or MAP_PRIVATE may change the * page table, but the new page will not be a subpage of hpage. */ - if (hpage + i !=3D page) + if (folio_page(folio, i) !=3D page) goto abort; } =20 @@ -1580,7 +1575,7 @@ int collapse_pte_mapped_thp(struct mm_struct *mm, uns= igned long addr, * page_table_lock) ptl nests inside pml. The less time we hold pml, * the better; but userfaultfd's mfill_atomic_pte() on a private VMA * inserts a valid as-if-COWed PTE without even looking up page cache. - * So page lock of hpage does not protect from it, so we must not drop + * So page lock of folio does not protect from it, so we must not drop * ptl before pgt_pmd is removed, so uffd private needs pml taken now. */ if (userfaultfd_armed(vma) && !(vma->vm_flags & VM_SHARED)) @@ -1604,7 +1599,7 @@ int collapse_pte_mapped_thp(struct mm_struct *mm, uns= igned long addr, continue; /* * We dropped ptl after the first scan, to do the mmu_notifier: - * page lock stops more PTEs of the hpage being faulted in, but + * page lock stops more PTEs of the folio being faulted in, but * does not stop write faults COWing anon copies from existing * PTEs; and does not stop those being swapped out or migrated. */ @@ -1613,7 +1608,7 @@ int collapse_pte_mapped_thp(struct mm_struct *mm, uns= igned long addr, goto abort; } page =3D vm_normal_page(vma, addr, ptent); - if (hpage + i !=3D page) + if (folio_page(folio, i) !=3D page) goto abort; =20 /* @@ -1632,8 +1627,8 @@ int collapse_pte_mapped_thp(struct mm_struct *mm, uns= igned long addr, =20 /* step 3: set proper refcount and mm_counters. */ if (nr_ptes) { - page_ref_sub(hpage, nr_ptes); - add_mm_counter(mm, mm_counter_file(hpage), -nr_ptes); + folio_ref_sub(folio, nr_ptes); + add_mm_counter(mm, mm_counter_file(&folio->page), -nr_ptes); } =20 /* step 4: remove empty page table */ @@ -1657,14 +1652,14 @@ int collapse_pte_mapped_thp(struct mm_struct *mm, u= nsigned long addr, maybe_install_pmd: /* step 5: install pmd entry */ result =3D install_pmd - ? set_huge_pmd(vma, haddr, pmd, hpage) + ? set_huge_pmd(vma, haddr, pmd, &folio->page) : SCAN_SUCCEED; - goto drop_hpage; + goto drop_folio; abort: if (nr_ptes) { flush_tlb_mm(mm); - page_ref_sub(hpage, nr_ptes); - add_mm_counter(mm, mm_counter_file(hpage), -nr_ptes); + folio_ref_sub(folio, nr_ptes); + add_mm_counter(mm, mm_counter_file(&folio->page), -nr_ptes); } if (start_pte) pte_unmap_unlock(start_pte, ptl); @@ -1672,9 +1667,9 @@ int collapse_pte_mapped_thp(struct mm_struct *mm, uns= igned long addr, spin_unlock(pml); if (notified) mmu_notifier_invalidate_range_end(&range); -drop_hpage: - unlock_page(hpage); - put_page(hpage); +drop_folio: + folio_unlock(folio); + folio_put(folio); return result; } =20 --=20 2.40.1