From nobody Thu Dec 18 18:57:15 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 3260FCDB465 for ; Mon, 16 Oct 2023 20:07:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234066AbjJPUHV (ORCPT ); Mon, 16 Oct 2023 16:07:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45894 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233991AbjJPUHD (ORCPT ); Mon, 16 Oct 2023 16:07:03 -0400 Received: from mail-pg1-x52c.google.com (mail-pg1-x52c.google.com [IPv6:2607:f8b0:4864:20::52c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C8F45EE for ; Mon, 16 Oct 2023 13:07:00 -0700 (PDT) Received: by mail-pg1-x52c.google.com with SMTP id 41be03b00d2f7-5a1d91a29a0so3670495a12.1 for ; Mon, 16 Oct 2023 13:07:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1697486820; x=1698091620; 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=x1jVF5fDDtB5E1xXw4u2h0Qq1/g1/HjZ8iamB/5OFoA=; b=aERMXq8DV73yjLippLpiuRtwzFcFw/WYuvqnlRbHHHfjn25nRadm3YMgWO+1fvmLSx 148Kk/6Ks/w2NmbKpcJNf3srriXyzfQLBAzLns7MnPq1Gcgb8uM1G91NNv5+cx8nuu3g Dy5pvdCTKsq9lMFuKCkrLohcsygvLqvKtvQ7FZdokG5AwRHw0YCGKQUXzp+eyrFZZf7Q a0ToPBFaoEtnRFfBEKfsLoz/r80av0d3BWaxzzdIiC/ra2PdNovzBWGb1JxAwpwQCFlC 5fM03Fn3X+GAqPeV23BOZNKMWjipUIYNY4ryxydn7dC8+nebZDZhvUmwXLOwujZ2IWMz JPLw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697486820; x=1698091620; 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=x1jVF5fDDtB5E1xXw4u2h0Qq1/g1/HjZ8iamB/5OFoA=; b=bgXX9plPnK4RB+j7RJaYl8LMevRm18WLMteDEDuZ0zY7/YGufd4SPEPDebvFmZRobC rA5ysTg8bSAjAFb3LaW/2dX6avNQzu1JXSPWtBUjqo3hJSjf9aY6y786uQKacznbXAVW wEMYLhIk7tlgLq0bp4PsWp7phYo1/zDRwWPpfswszQvn1+XXpDyb9qGhWLEaPfgEdWgB ql8sDTOPJiOCkc/sqBGJP47jW3I1hLh9JC7WLkYUJKqIkur4iPkwhWFtTrx3FOaPpy9p fzT2CzlQxouijmVsmgnjXATd6uRdlBvjGFIliZjL9XWes89qvu9Sft5h7N1ewG7j2Zyp fDKg== X-Gm-Message-State: AOJu0YwW9NpTMRRZ4dQTgFrJLChYOQSoJAPPPWoa+WuXETbVZmZWGEWe pnT/NPXYOWEUtuMtSL9/5qd+zJe/HPE= X-Google-Smtp-Source: AGHT+IFPrGp2LxyePxJ2SGP9Uv5jwNSK/jlVnwKjorWrK64yF1KjrffZTKbz4NdtbcNvcYG72+5GCQ== X-Received: by 2002:a17:90b:368d:b0:27d:f85:9505 with SMTP id mj13-20020a17090b368d00b0027d0f859505mr159453pjb.24.1697486820185; Mon, 16 Oct 2023 13:07:00 -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 t16-20020a17090b019000b002772faee740sm5162367pjs.5.2023.10.16.13.06.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 Oct 2023 13:06:59 -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 5/5] mm/khugepaged: Convert collapse_pte_mapped_thp() to use folios Date: Mon, 16 Oct 2023 13:05:10 -0700 Message-Id: <20231016200510.7387-6-vishal.moola@gmail.com> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20231016200510.7387-1-vishal.moola@gmail.com> References: <20231016200510.7387-1-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 70bba8ddea13..99c437979848 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1471,7 +1471,7 @@ 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; @@ -1504,19 +1504,14 @@ 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); @@ -1530,13 +1525,13 @@ 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; @@ -1561,7 +1556,7 @@ 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 @@ -1576,7 +1571,7 @@ 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)) @@ -1600,7 +1595,7 @@ 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. */ @@ -1609,7 +1604,7 @@ 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 /* @@ -1628,8 +1623,8 @@ 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 */ @@ -1653,14 +1648,14 @@ 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); @@ -1668,9 +1663,9 @@ 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