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 AE093C433B4 for ; Tue, 13 Apr 2021 06:57:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 867F3613B6 for ; Tue, 13 Apr 2021 06:57:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237032AbhDMG5T (ORCPT ); Tue, 13 Apr 2021 02:57:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44174 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245189AbhDMG5J (ORCPT ); Tue, 13 Apr 2021 02:57:09 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 804B0C061756 for ; Mon, 12 Apr 2021 23:56:50 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id t9so4737272ybd.11 for ; Mon, 12 Apr 2021 23:56:50 -0700 (PDT) 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=ClG8Hyf5TTtr5EO4ugQ7lEF5g9jg1Khbtn9fiHHHUO4=; b=Bz/NCIqrnVElEbVXzKEuDo/rZuQj9KS3qgxTKdWtHhz5pm8i/K2zNVWoVZLOT3rUSR LsBDpHnPsr/ZpnLlRjgBWaTe1LWedpUZEH5ms55YmlHa6b6jgezdJL3RT6PspSs7PC0D X2Cp8BNNHZoXRtz4WK/5SGU3p+K+AzCV3OWzqDVroA6mh4+0ezV8mgPVSzwRPD5kb0gr h1rkXixNjOMz9WdBgGoShJ+IdH8LzpJqTgis+qWDrFblJngv4Of0j7VP1YZiUBDZBIO8 UPhfTPDB4QZtT8MN0GMlMXbeAlUWYEo/7WcySgFwiSO0kt7YfrA1ke9uBnFFX4PziJEZ ISaA== 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=ClG8Hyf5TTtr5EO4ugQ7lEF5g9jg1Khbtn9fiHHHUO4=; b=Ln0JHJYmVa2eSlKqpGtl/4uP0U/tFRs/pk5G6Sl8Iec4RrR5oqZdSeZC19j8TSeMUO DmIZ5X8vhdMmgBAkWF7E4NxzMbBEJfzjseP4tvMHiWSQ+ZWeCLuYCrW6DEaObyCK+T7t zIVNPEeJOIg1zDbSyPA0EVnJqpe6Gkec8ahBEG03YbyTmfuG6vb0McULQljJ5OhniFfX UripKlgaIV1a55hf1KsyL81MPaz5nGMe/cCHrm8EHqvFhxWzKWFO1Qk4Tc1VI45wYTHS YVo0QOvbSbampG2ears9RXvYdJ9QVT1M8JfO5/+bVnbN3VbRLxG7g4jVuwkA4zPKOHYI dISw== X-Gm-Message-State: AOAM531fA312edJF5bN6zMI4xlJ2NDI7L0pqlv/7HXEcSl6sGX7pfMuO 8LvKSxlzMxN/BLov7kCFr0vqNk/bYbk= X-Google-Smtp-Source: ABdhPJwc8JriuoHPQ23GGBqKR69oc5Gp+cE2EiR0xXWJLv2glle7kn2s+OHctKLTVqR0qrsNshOCMzVz8BQ= X-Received: from yuzhao.bld.corp.google.com ([2620:15c:183:200:d02d:cccc:9ebe:9fe9]) (user=yuzhao job=sendgmr) by 2002:a25:8b0f:: with SMTP id i15mr42151231ybl.277.1618297009506; Mon, 12 Apr 2021 23:56:49 -0700 (PDT) Date: Tue, 13 Apr 2021 00:56:23 -0600 In-Reply-To: <20210413065633.2782273-1-yuzhao@google.com> Message-Id: <20210413065633.2782273-7-yuzhao@google.com> Mime-Version: 1.0 References: <20210413065633.2782273-1-yuzhao@google.com> X-Mailer: git-send-email 2.31.1.295.g9ea45b61b8-goog Subject: [PATCH v2 06/16] mm, x86: support the access bit on non-leaf PMD entries From: Yu Zhao To: linux-mm@kvack.org Cc: Alex Shi , Andi Kleen , Andrew Morton , Benjamin Manes , Dave Chinner , Dave Hansen , Hillf Danton , Jens Axboe , Johannes Weiner , Jonathan Corbet , Joonsoo Kim , Matthew Wilcox , Mel Gorman , Miaohe Lin , Michael Larabel , Michal Hocko , Michel Lespinasse , Rik van Riel , Roman Gushchin , Rong Chen , SeongJae Park , Tim Chen , Vlastimil Babka , Yang Shi , Ying Huang , Zi Yan , linux-kernel@vger.kernel.org, lkp@lists.01.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 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. [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 | 9 +++++++++ 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, 17 insertions(+), 4 deletions(-) diff --git a/arch/Kconfig b/arch/Kconfig index ecfd3520b676..cbd7f66734ee 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -782,6 +782,15 @@ config HAVE_ARCH_TRANSPARENT_HUGEPAGE config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD bool +config HAVE_ARCH_PARENT_PMD_YOUNG + bool + depends on PGTABLE_LEVELS > 2 + 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 -- 2.31.1.295.g9ea45b61b8-goog