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 3FBCEC433B4 for ; Thu, 20 May 2021 06:54:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2678D6108C for ; Thu, 20 May 2021 06:54:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230467AbhETGzf (ORCPT ); Thu, 20 May 2021 02:55:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37890 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230435AbhETGz2 (ORCPT ); Thu, 20 May 2021 02:55:28 -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 DC741C0613CE for ; Wed, 19 May 2021 23:54:07 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id 129-20020a2504870000b0290513326cc5e0so8674080ybe.10 for ; Wed, 19 May 2021 23:54:07 -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=SyTpiiLQc7KnB8Q1E8X3BxXutjquJ4KYbVlpDQgVi/g=; b=F/5vtOLfn2hWqJCcZJILEPNvAi4G3UC/HROV8n8s10GH7JhHnrGHdEho6MiIGVETaO sHn+wn+lopXgJMLEqp5WqaQ769JJNG7YB4Pq15oo9pv+HRPYGP/d500+gP+KrGyChFzI iRtkvAcNwlgumar+mpa5HZRGCb08Jm1ZBJ5134Kg6M2RP3KBMa9LpRBW+jA/uB2ZH6dY SHmfSiGBjz0MLdKbjMO0ZC+E0iCgLKKyI3liy35dgrf7U0uAsmS+Tq+vBabFfUY8cvI2 9S4m0Grod6BK2vh7Cxh9tBxuiOnpUkk6GOwodZ5MXTpgU9J25Ztod8Cas20KXVuUUu5L 0caQ== 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=SyTpiiLQc7KnB8Q1E8X3BxXutjquJ4KYbVlpDQgVi/g=; b=I/lOZpe4tWCS0mala3TZsfeszZC2f6ezlF6QsZ4a/ik+ur09NYRA+x5bJGwlW5GDlq UnLRSTXE7lfK71dSWsWOnbdahNawKurDhQQHAWYazRhXZbx8wQr8tVsCQRJt62tjdH10 3hySRpK88u8siMlEwsnnjOD9xPsxcVvC9q60ppd6Eg2OjbtByyWxV86qM2x45/Wp9SgS 1K0/jwK6L1A8aN+ccrl6RiewC05OjfkXbKE3qp2X4jLzxo0Z5jchuk4yzUI9a9UtqjR2 jluXY0tCVPqedtSHAZ1h+oHspBuclW26af/5c7EGck5IwrADYKN8hL9LfA0GmuxthLa8 CT+g== X-Gm-Message-State: AOAM530i7XGlRCP9jxfMmcb0QrUXw8gBhH02/rSREHScRnCCUJvVu8zh smjHRFK1+f6BrShUrxMXHYEhJlEv03M= X-Google-Smtp-Source: ABdhPJxef10azDAzK7UEGotre/hx9MbP+rt8RSM5uDH+7LMog0h8qkdAugFcXq/qcLN78UEvnUxUn/nobaI= X-Received: from yuzhao.bld.corp.google.com ([2620:15c:183:200:595d:62ee:f08:8e83]) (user=yuzhao job=sendgmr) by 2002:a25:2009:: with SMTP id g9mr4983935ybg.198.1621493646666; Wed, 19 May 2021 23:54:06 -0700 (PDT) Date: Thu, 20 May 2021 00:53:45 -0600 In-Reply-To: <20210520065355.2736558-1-yuzhao@google.com> Message-Id: <20210520065355.2736558-5-yuzhao@google.com> Mime-Version: 1.0 References: <20210520065355.2736558-1-yuzhao@google.com> X-Mailer: git-send-email 2.31.1.751.gd2f1c929bd-goog Subject: [PATCH v3 04/14] 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 , Dave Chinner , Dave Hansen , Donald Carr , Hillf Danton , Jens Axboe , Johannes Weiner , Jonathan Corbet , Joonsoo Kim , Konstantin Kharlamov , Marcus Seyfarth , Matthew Wilcox , Mel Gorman , Miaohe Lin , Michael Larabel , Michal Hocko , Michel Lespinasse , Rik van Riel , Roman Gushchin , 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 , Konstantin Kharlamov Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org List-Archive: 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 Tested-by: Konstantin Kharlamov --- 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 c45b770d3579..e3812adc69f7 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -826,6 +826,15 @@ 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 if they do not see the accessed bit. + config HAVE_ARCH_HUGE_VMAP bool diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 0045e1b44190..f619055c4537 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -170,6 +170,7 @@ 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_USERFAULTFD_MINOR if X86_64 && USERFAULTFD select HAVE_ARCH_VMAP_STACK if X86_64 diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index b1099f2d9800..3a24d2af4e9b 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 d27cf69e811d..b968d6bd28b6 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 46b13780c2c8..94ecc1d277a2 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 -- 2.31.1.751.gd2f1c929bd-goog