From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CFB78C43331 for ; Sat, 13 Mar 2021 07:59:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A37AF64F1E for ; Sat, 13 Mar 2021 07:59:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233446AbhCMH6j (ORCPT ); Sat, 13 Mar 2021 02:58:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58976 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232627AbhCMH6F (ORCPT ); Sat, 13 Mar 2021 02:58:05 -0500 Received: from mail-qt1-x84a.google.com (mail-qt1-x84a.google.com [IPv6:2607:f8b0:4864:20::84a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EF963C061574 for ; Fri, 12 Mar 2021 23:58:04 -0800 (PST) Received: by mail-qt1-x84a.google.com with SMTP id a16so3377560qtw.1 for ; Fri, 12 Mar 2021 23:58:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=9FOrNXENvEBq+xjcXdvWYV76Tj/52PeZfpdHZpBdeTw=; b=CZNFSLn1Vr+7g91u2WdSPY2RASOoMeGVnEu8XS9ogwps7Gq+7F5umE3fWsyowJpBWD /BpSgazEV0uTx/142ccxmLjj6Tc5kR7KGsb79Ptj4azaGNuJBT032A7MXAqita6Xkryl 6IanFkwVS4tC+SsZAZtk+kuQzdp1pO5Pnx+cXwdQzEVQmCkWjuUnjKzoEPGf4IlnkcFb QOa5YU3bEwcfmAFIwkc2tWsdZ2h8rKKycxzT/zHBKI265GiGZGNofgaHIdU33DduoJGc Q3y72dvencUMJG5nccrm3sqMC+9s98wb5AiyP7gwQH8cNu/oUBPDF/k1zMnv1QbL0y4q Wkmw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=9FOrNXENvEBq+xjcXdvWYV76Tj/52PeZfpdHZpBdeTw=; b=dwfL2qqtOLyHknmJLTbNquIIE99M3co4RRcjM8ZHW7E3b22r0qS7/uSdIuLxhwPvQA Y3LL2jZN2S3rNEY31iqcQo0XPmDjtQwb13jd9vmVGL+LLS5tszC4uUapyiV0oPCH5uwL smIUxO+PPvwuZT1NgqDpJ05pyAL6HNc5tjDAhFLsgZFN/eS2938P25wiN4+HDX1vPlLc PXD85IpbqplkrTukFj4waHLj2xp8v/FPA9XzbBiYpaKEr1bL5w6oyKCxl6mnhZr0A9h6 m3QW2oQAPQpKG6YqSR4gB8S9wvQ5RcQOj/4jcVgdKH2lIq48/Tc9tYuJNF3HuISISSMR K2Aw== X-Gm-Message-State: AOAM530QAe48ahNQ/TdZi8OsNzl8PRShs8X4B4mC6ejSQSSJgG9mU0dS C8+Z0ZLOLiEDu/n5izcyhgbt0bjgPuM= X-Google-Smtp-Source: ABdhPJx3v9fo9fGIto8kHzW5LTGjVA6UTKRtTeuo4NwnDLlQop9mIBVZK8pHZLGtADbIHe5kSQ6HeS7hVrU= X-Received: from yuzhao.bld.corp.google.com ([2620:15c:183:200:f931:d3e4:faa0:4f74]) (user=yuzhao job=sendgmr) by 2002:a0c:cb0c:: with SMTP id o12mr15467752qvk.54.1615622284101; Fri, 12 Mar 2021 23:58:04 -0800 (PST) Date: Sat, 13 Mar 2021 00:57:39 -0700 In-Reply-To: <20210313075747.3781593-1-yuzhao@google.com> Message-Id: <20210313075747.3781593-7-yuzhao@google.com> Mime-Version: 1.0 References: <20210313075747.3781593-1-yuzhao@google.com> X-Mailer: git-send-email 2.31.0.rc2.261.g7f71774620-goog Subject: [PATCH v1 06/14] mm, x86: support the access bit on non-leaf PMD entries From: Yu Zhao To: linux-mm@kvack.org Cc: Alex Shi , Andrew Morton , Dave Hansen , Hillf Danton , Johannes Weiner , Joonsoo Kim , Matthew Wilcox , Mel Gorman , Michal Hocko , Roman Gushchin , Vlastimil Babka , Wei Yang , Yang Shi , Ying Huang , linux-kernel@vger.kernel.org, page-reclaim@google.com, Yu Zhao Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Archived-At: List-Archive: List-Post: Some architectures support the accessed bit on non-leaf PMD entries (parents) in addition to leaf PTE entries (children) where pages are mapped, e.g., x86_64 sets the accessed bit on a parent when using it as part of linear-address translation [1]. Page table walkers who are interested in the accessed bit on children can take advantage of this: they do not need to search the children when the accessed bit is not set on a parent, given that they have previously cleared the accessed bit on this parent in addition to its children. [1]: Intel 64 and IA-32 Architectures Software Developer's Manual Volume 3 (October 2019), section 4.8 Signed-off-by: Yu Zhao --- arch/Kconfig | 8 ++++++++ arch/x86/Kconfig | 1 + arch/x86/include/asm/pgtable.h | 2 +- arch/x86/mm/pgtable.c | 5 ++++- include/linux/pgtable.h | 4 ++-- 5 files changed, 16 insertions(+), 4 deletions(-) diff --git a/arch/Kconfig b/arch/Kconfig index 2bb30673d8e6..137446d17732 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -783,6 +783,14 @@ config HAVE_ARCH_TRANSPARENT_HUGEPAGE config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD bool +config HAVE_ARCH_PARENT_PMD_YOUNG + bool + help + Architectures that select this are able to set the accessed bit on + non-leaf PMD entries in addition to leaf PTE entries where pages are + mapped. For them, page table walkers that clear the accessed bit may + stop at non-leaf PMD entries when they do not see the accessed bit. + config HAVE_ARCH_HUGE_VMAP bool diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 2792879d398e..b5972eb82337 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -163,6 +163,7 @@ config X86 select HAVE_ARCH_TRACEHOOK select HAVE_ARCH_TRANSPARENT_HUGEPAGE select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 + select HAVE_ARCH_PARENT_PMD_YOUNG if X86_64 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD select HAVE_ARCH_VMAP_STACK if X86_64 select HAVE_ARCH_WITHIN_STACK_FRAMES diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index a02c67291cfc..a6b5cfe1fc5a 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -846,7 +846,7 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd) static inline int pmd_bad(pmd_t pmd) { - return (pmd_flags(pmd) & ~_PAGE_USER) != _KERNPG_TABLE; + return ((pmd_flags(pmd) | _PAGE_ACCESSED) & ~_PAGE_USER) != _KERNPG_TABLE; } static inline unsigned long pages_to_mb(unsigned long npg) diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index f6a9e2e36642..1c27e6f43f80 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -550,7 +550,7 @@ int ptep_test_and_clear_young(struct vm_area_struct *vma, return ret; } -#ifdef CONFIG_TRANSPARENT_HUGEPAGE +#if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HAVE_ARCH_PARENT_PMD_YOUNG) int pmdp_test_and_clear_young(struct vm_area_struct *vma, unsigned long addr, pmd_t *pmdp) { @@ -562,6 +562,9 @@ int pmdp_test_and_clear_young(struct vm_area_struct *vma, return ret; } +#endif + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE int pudp_test_and_clear_young(struct vm_area_struct *vma, unsigned long addr, pud_t *pudp) { diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index 5e772392a379..08dd9b8c055a 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -193,7 +193,7 @@ static inline int ptep_test_and_clear_young(struct vm_area_struct *vma, #endif #ifndef __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG -#ifdef CONFIG_TRANSPARENT_HUGEPAGE +#if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HAVE_ARCH_PARENT_PMD_YOUNG) static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma, unsigned long address, pmd_t *pmdp) @@ -214,7 +214,7 @@ static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma, BUILD_BUG(); return 0; } -#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ +#endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HAVE_ARCH_PARENT_PMD_YOUNG */ #endif #ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH -- 2.31.0.rc2.261.g7f71774620-goog