From nobody Fri May 8 05:14:47 2026 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 AFDA5C433F5 for ; Tue, 10 May 2022 11:13:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240760AbiEJLRR (ORCPT ); Tue, 10 May 2022 07:17:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48844 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240723AbiEJLRK (ORCPT ); Tue, 10 May 2022 07:17:10 -0400 Received: from out30-133.freemail.mail.aliyun.com (out30-133.freemail.mail.aliyun.com [115.124.30.133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CFB2922242D for ; Tue, 10 May 2022 04:13:12 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R431e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04395;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=12;SR=0;TI=SMTPD_---0VCr6xlO_1652181186; Received: from localhost(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0VCr6xlO_1652181186) by smtp.aliyun-inc.com(127.0.0.1); Tue, 10 May 2022 19:13:06 +0800 From: Baolin Wang To: catalin.marinas@arm.com, will@kernel.org, mike.kravetz@oracle.com, akpm@linux-foundation.org Cc: songmuchun@bytedance.com, willy@infradead.org, anshuman.khandual@arm.com, christophe.leroy@csgroup.eu, baolin.wang@linux.alibaba.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 1/2] arm64/hugetlb: Use ptep_get() to get the pte value of a huge page Date: Tue, 10 May 2022 19:12:52 +0800 Message-Id: <6aabddaf4cae5ae2205c3a7df9b9e15dbd61b641.1652180088.git.baolin.wang@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: References: In-Reply-To: References: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" The original huge_ptep_get() on ARM64 is just a wrapper of ptep_get(), which will not take into account any contig-PTEs dirty and access bits. Meanwhile we will implement a new ARM64-specific huge_ptep_get() interface in following patch, which will take into account any contig-PTEs dirty and access bits and only be allowed to pass the head pte of a contig-PTE/PMD size page. Thus change to use ptep_get() to get the pte value of a huge page as a preparation. Signed-off-by: Baolin Wang Reviewed-by: Muchun Song --- arch/arm64/mm/hugetlbpage.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c index ca8e65c..be5e2f3 100644 --- a/arch/arm64/mm/hugetlbpage.c +++ b/arch/arm64/mm/hugetlbpage.c @@ -172,7 +172,7 @@ static pte_t get_clear_flush(struct mm_struct *mm, unsigned long pgsize, unsigned long ncontig) { - pte_t orig_pte =3D huge_ptep_get(ptep); + pte_t orig_pte =3D ptep_get(ptep); bool valid =3D pte_valid(orig_pte); unsigned long i, saddr =3D addr; =20 @@ -385,7 +385,7 @@ pte_t huge_ptep_get_and_clear(struct mm_struct *mm, { int ncontig; size_t pgsize; - pte_t orig_pte =3D huge_ptep_get(ptep); + pte_t orig_pte =3D ptep_get(ptep); =20 if (!pte_cont(orig_pte)) return ptep_get_and_clear(mm, addr, ptep); @@ -408,11 +408,11 @@ static int __cont_access_flags_changed(pte_t *ptep, p= te_t pte, int ncontig) { int i; =20 - if (pte_write(pte) !=3D pte_write(huge_ptep_get(ptep))) + if (pte_write(pte) !=3D pte_write(ptep_get(ptep))) return 1; =20 for (i =3D 0; i < ncontig; i++) { - pte_t orig_pte =3D huge_ptep_get(ptep + i); + pte_t orig_pte =3D ptep_get(ptep + i); =20 if (pte_dirty(pte) !=3D pte_dirty(orig_pte)) return 1; --=20 1.8.3.1 From nobody Fri May 8 05:14:47 2026 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 42E2FC433F5 for ; Tue, 10 May 2022 11:13:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240750AbiEJLRN (ORCPT ); Tue, 10 May 2022 07:17:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48790 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240719AbiEJLRJ (ORCPT ); Tue, 10 May 2022 07:17:09 -0400 Received: from out30-42.freemail.mail.aliyun.com (out30-42.freemail.mail.aliyun.com [115.124.30.42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 20BEA21F1E4 for ; Tue, 10 May 2022 04:13:11 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R101e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04395;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=12;SR=0;TI=SMTPD_---0VCr6xmA_1652181187; Received: from localhost(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0VCr6xmA_1652181187) by smtp.aliyun-inc.com(127.0.0.1); Tue, 10 May 2022 19:13:08 +0800 From: Baolin Wang To: catalin.marinas@arm.com, will@kernel.org, mike.kravetz@oracle.com, akpm@linux-foundation.org Cc: songmuchun@bytedance.com, willy@infradead.org, anshuman.khandual@arm.com, christophe.leroy@csgroup.eu, baolin.wang@linux.alibaba.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 2/2] arm64/hugetlb: Implement arm64 specific huge_ptep_get() Date: Tue, 10 May 2022 19:12:53 +0800 Message-Id: X-Mailer: git-send-email 1.8.3.1 In-Reply-To: References: In-Reply-To: References: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Now we use huge_ptep_get() to get the pte value of a hugetlb page, however it will only return one specific pte value for the CONT-PTE or CONT-PMD size hugetlb on ARM64 system, which can contain seravel continuous pte or pmd entries with same page table attributes. And it will not take into account the subpages' dirty or young bits of a CONT-PTE/PMD size hugetlb page. So the huge_ptep_get() is inconsistent with huge_ptep_get_and_clear(), which already takes account the dirty or young bits for any subpages in this CONT-PTE/PMD size hugetlb [1]. Meanwhile we can miss dirty or young flags statistics for hugetlb pages with current huge_ptep_get(), such as the gather_hugetlb_stats() function, and CONT-PTE/PMD hugetlb monitoring with DAMON. Thus define an ARM64 specific huge_ptep_get() implementation, that will take into account any subpages' dirty or young bits for CONT-PTE/PMD size hugetlb page, for those functions that want to check the dirty and young flags of a hugetlb page. [1] https://lore.kernel.org/linux-mm/85bd80b4-b4fd-0d3f-a2e5-149559f2f387@o= racle.com/ Suggested-by: Muchun Song Signed-off-by: Baolin Wang Reviewed-by: Muchun Song --- arch/arm64/include/asm/hugetlb.h | 2 ++ arch/arm64/mm/hugetlbpage.c | 24 ++++++++++++++++++++++++ 2 files changed, 26 insertions(+) diff --git a/arch/arm64/include/asm/hugetlb.h b/arch/arm64/include/asm/huge= tlb.h index 616b2ca..1fd2846 100644 --- a/arch/arm64/include/asm/hugetlb.h +++ b/arch/arm64/include/asm/hugetlb.h @@ -44,6 +44,8 @@ extern pte_t huge_ptep_clear_flush(struct vm_area_struct = *vma, #define __HAVE_ARCH_HUGE_PTE_CLEAR extern void huge_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep, unsigned long sz); +#define __HAVE_ARCH_HUGE_PTEP_GET +extern pte_t huge_ptep_get(pte_t *ptep); extern void set_huge_swap_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pte, unsigned long sz); #define set_huge_swap_pte_at set_huge_swap_pte_at diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c index be5e2f3..8fb0198 100644 --- a/arch/arm64/mm/hugetlbpage.c +++ b/arch/arm64/mm/hugetlbpage.c @@ -158,6 +158,30 @@ static inline int num_contig_ptes(unsigned long size, = size_t *pgsize) return contig_ptes; } =20 +pte_t huge_ptep_get(pte_t *ptep) +{ + int ncontig, i; + size_t pgsize; + pte_t orig_pte =3D ptep_get(ptep); + + if (!pte_present(orig_pte) || !pte_cont(orig_pte)) + return orig_pte; + + ncontig =3D num_contig_ptes(page_size(pte_page(orig_pte)), &pgsize); + + for (i =3D 0; i < ncontig; i++, ptep++) { + pte_t pte =3D ptep_get(ptep); + + if (pte_dirty(pte)) + orig_pte =3D pte_mkdirty(orig_pte); + + if (pte_young(pte)) + orig_pte =3D pte_mkyoung(orig_pte); + } + + return orig_pte; +} + /* * Changing some bits of contiguous entries requires us to follow a * Break-Before-Make approach, breaking the whole contiguous set --=20 1.8.3.1