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a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1753334595; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=BvKc0MPFZ96VL7Xz/7u0VA/SqRKAP7a/ChBeUD/s/KI=; b=1P8QWKmm30tS2s1c4mtFfDymqOLBBpURuLge/pcmCRfVl5hJLXhG1OFXFAH28Nnb7HZ7oU KURT5SeLJTPjUGdY+3L/zi9AqSli7vaQSJgwRlIwvtwdTrkDw3cvF1kkosi1CvJc5+Zxal sSQWPs/XPUyHHO+oLCBg4fDoQHs8Af4= Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 6BDCD1CC4; Wed, 23 Jul 2025 22:23:08 -0700 (PDT) Received: from MacBook-Pro.blr.arm.com (unknown [10.164.18.48]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 156693F66E; Wed, 23 Jul 2025 22:23:10 -0700 (PDT) From: Dev Jain To: akpm@linux-foundation.org, david@redhat.com Cc: ziy@nvidia.com, baolin.wang@linux.alibaba.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, npache@redhat.com, ryan.roberts@arm.com, baohua@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Dev Jain Subject: [PATCH v4 1/3] mm: add get_and_clear_ptes() and clear_ptes() Date: Thu, 24 Jul 2025 10:52:59 +0530 Message-Id: <20250724052301.23844-2-dev.jain@arm.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) In-Reply-To: <20250724052301.23844-1-dev.jain@arm.com> References: <20250724052301.23844-1-dev.jain@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: A236540003 X-Stat-Signature: xednb9ezesogqiaobjcrk4nfj6rb1uog X-HE-Tag: 1753334595-856421 X-HE-Meta: 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 K3MEHnjJ AzdJJXtgO0fkGPcZAqmi4eIwU+vrfsIiRPtzpcBUrqxWXHIsKwNi/LIJQ06GwXDutgCCotUvI0trTtGAq2DUJYIcCaW7SpGimOfLfQIpSGsuyoppU4AaZFY7f5Du+ZNfjmexq3pz3JIDXtW3rgMCr0zGaHtqKTaAV4sacNJAGhxCiF5vLQCmJXGCLId7Dpadxtw88ymFqrgLXEPS0HfrzGkafjerrZMKq1R72hoZxO5z6wI75EMwGC19+RbSVSAU8iWofadx3ZZsTMWsS7Qym5nCCQ691NVlzoKwi X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: David Hildenbrand Let's add variants to be used where "full" does not apply -- which will be the majority of cases in the future. "full" really only applies if we are about to tear down a full MM. Use get_and_clear_ptes() in existing code, clear_ptes() users will be added next. Reviewed-by: Baolin Wang Signed-off-by: David Hildenbrand Signed-off-by: Dev Jain --- arch/arm64/mm/mmu.c | 2 +- include/linux/pgtable.h | 45 +++++++++++++++++++++++++++++++++++++++++ mm/mremap.c | 2 +- mm/rmap.c | 2 +- 4 files changed, 48 insertions(+), 3 deletions(-) diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index abd9725796e9..20a89ab97dc5 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -1528,7 +1528,7 @@ early_initcall(prevent_bootmem_remove_init); pte_t modify_prot_start_ptes(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep, unsigned int nr) { - pte_t pte = get_and_clear_full_ptes(vma->vm_mm, addr, ptep, nr, /* full = */ 0); + pte_t pte = get_and_clear_ptes(vma->vm_mm, addr, ptep, nr); if (alternative_has_cap_unlikely(ARM64_WORKAROUND_2645198)) { /* diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index e3b99920be05..4c035637eeb7 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -736,6 +736,29 @@ static inline pte_t get_and_clear_full_ptes(struct mm_struct *mm, } #endif +/** + * get_and_clear_ptes - Clear present PTEs that map consecutive pages of + * the same folio, collecting dirty/accessed bits. + * @mm: Address space the pages are mapped into. + * @addr: Address the first page is mapped at. + * @ptep: Page table pointer for the first entry. + * @nr: Number of entries to clear. + * + * Use this instead of get_and_clear_full_ptes() if it is known that we don't + * need to clear the full mm, which is mostly the case. + * + * Note that PTE bits in the PTE range besides the PFN can differ. For example, + * some PTEs might be write-protected. + * + * Context: The caller holds the page table lock. The PTEs map consecutive + * pages that belong to the same folio. The PTEs are all in the same PMD. + */ +static inline pte_t get_and_clear_ptes(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, unsigned int nr) +{ + return get_and_clear_full_ptes(mm, addr, ptep, nr, 0); +} + #ifndef clear_full_ptes /** * clear_full_ptes - Clear present PTEs that map consecutive pages of the same @@ -768,6 +791,28 @@ static inline void clear_full_ptes(struct mm_struct *mm, unsigned long addr, } #endif +/** + * clear_ptes - Clear present PTEs that map consecutive pages of the same folio. + * @mm: Address space the pages are mapped into. + * @addr: Address the first page is mapped at. + * @ptep: Page table pointer for the first entry. + * @nr: Number of entries to clear. + * + * Use this instead of clear_full_ptes() if it is known that we don't need to + * clear the full mm, which is mostly the case. + * + * Note that PTE bits in the PTE range besides the PFN can differ. For example, + * some PTEs might be write-protected. + * + * Context: The caller holds the page table lock. The PTEs map consecutive + * pages that belong to the same folio. The PTEs are all in the same PMD. + */ +static inline void clear_ptes(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, unsigned int nr) +{ + clear_full_ptes(mm, addr, ptep, nr, 0); +} + /* * If two threads concurrently fault at the same page, the thread that * won the race updates the PTE and its local TLB/Cache. The other thread diff --git a/mm/mremap.c b/mm/mremap.c index ac39845e9718..677a4d744df9 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -280,7 +280,7 @@ static int move_ptes(struct pagetable_move_control *pmc, old_pte, max_nr_ptes); force_flush = true; } - pte = get_and_clear_full_ptes(mm, old_addr, old_ptep, nr_ptes, 0); + pte = get_and_clear_ptes(mm, old_addr, old_ptep, nr_ptes); pte = move_pte(pte, old_addr, new_addr); pte = move_soft_dirty_pte(pte); diff --git a/mm/rmap.c b/mm/rmap.c index f93ce27132ab..568198e9efc2 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -2036,7 +2036,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, flush_cache_range(vma, address, end_addr); /* Nuke the page table entry. */ - pteval = get_and_clear_full_ptes(mm, address, pvmw.pte, nr_pages, 0); + pteval = get_and_clear_ptes(mm, address, pvmw.pte, nr_pages); /* * We clear the PTE but do not flush so potentially * a remote CPU could still be writing to the folio. -- 2.30.2