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b=RFFG+r3QyVbxX0P0Acghf98y1J6eymXn6eiwPD7EhtP+8Oo1/4nZHL3lMD2K5HnoNUKS5Wnhsizbj/sPW1kfFLYOfQktCozwQQRDiXrObbgQdmkcGw9hQXFvEXjlgpmHbE08CSZqiUndVzoicehQD+EjByEOXZUZHgB/4RqyPW5D2dvBD23VltzD0HY4LjmAaeDA1auF+KLZEBW8LBj/dynuYjZRdeWpqChAqPeZI7du757SXM7NHGUJnvp7FDJG/XOxlwiZ/ecveY1fr5mbJomVOq/4S1qJZykTVxK8AVCkfUaCH0B+8+frA0L1Xz6dzOQu0kTiq2ImO3BpK7FZYg== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from DS0PR12MB7726.namprd12.prod.outlook.com (2603:10b6:8:130::6) by BY5PR12MB4148.namprd12.prod.outlook.com (2603:10b6:a03:208::23) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7918.20; Tue, 10 Sep 2024 04:15:30 +0000 Received: from DS0PR12MB7726.namprd12.prod.outlook.com ([fe80::953f:2f80:90c5:67fe]) by DS0PR12MB7726.namprd12.prod.outlook.com ([fe80::953f:2f80:90c5:67fe%3]) with mapi id 15.20.7918.024; Tue, 10 Sep 2024 04:15:30 +0000 From: Alistair Popple To: dan.j.williams@intel.com, linux-mm@kvack.org Cc: Alistair Popple , vishal.l.verma@intel.com, dave.jiang@intel.com, logang@deltatee.com, bhelgaas@google.com, jack@suse.cz, jgg@ziepe.ca, catalin.marinas@arm.com, will@kernel.org, mpe@ellerman.id.au, npiggin@gmail.com, dave.hansen@linux.intel.com, ira.weiny@intel.com, willy@infradead.org, djwong@kernel.org, tytso@mit.edu, linmiaohe@huawei.com, david@redhat.com, peterx@redhat.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, nvdimm@lists.linux.dev, linux-cxl@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, jhubbard@nvidia.com, hch@lst.de, david@fromorbit.com Subject: [PATCH 07/12] huge_memory: Allow mappings of PMD sized pages Date: Tue, 10 Sep 2024 14:14:32 +1000 Message-ID: X-Mailer: git-send-email 2.43.0 In-Reply-To: References: X-ClientProxiedBy: SYAPR01CA0046.ausprd01.prod.outlook.com (2603:10c6:1:1::34) To DS0PR12MB7726.namprd12.prod.outlook.com (2603:10b6:8:130::6) Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS0PR12MB7726:EE_|BY5PR12MB4148:EE_ X-MS-Office365-Filtering-Correlation-Id: b139175d-3b9e-4e2c-ea1c-08dcd14f3503 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|376014|7416014|1800799024; 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To allow these to be managed the same as normal pages introduce dax_insert_pfn_pmd. This will map the entire PMD-sized folio and take references as it would for a normally mapped page. This is distinct from the current mechanism, vmf_insert_pfn_pmd, which simply inserts a special devmap PMD entry into the page table without holding a reference to the page for the mapping. Signed-off-by: Alistair Popple --- include/linux/huge_mm.h | 1 +- mm/huge_memory.c | 57 ++++++++++++++++++++++++++++++++++-------- 2 files changed, 48 insertions(+), 10 deletions(-) diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index d3a1872..eaf3f78 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -40,6 +40,7 @@ int change_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, vm_fault_t vmf_insert_pfn_pmd(struct vm_fault *vmf, pfn_t pfn, bool write); vm_fault_t vmf_insert_pfn_pud(struct vm_fault *vmf, pfn_t pfn, bool write); +vm_fault_t dax_insert_pfn_pmd(struct vm_fault *vmf, pfn_t pfn, bool write); vm_fault_t dax_insert_pfn_pud(struct vm_fault *vmf, pfn_t pfn, bool write); enum transparent_hugepage_flag { diff --git a/mm/huge_memory.c b/mm/huge_memory.c index e8985a4..790041e 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1237,14 +1237,12 @@ static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, { struct mm_struct *mm = vma->vm_mm; pmd_t entry; - spinlock_t *ptl; - ptl = pmd_lock(mm, pmd); if (!pmd_none(*pmd)) { if (write) { if (pmd_pfn(*pmd) != pfn_t_to_pfn(pfn)) { WARN_ON_ONCE(!is_huge_zero_pmd(*pmd)); - goto out_unlock; + return; } entry = pmd_mkyoung(*pmd); entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); @@ -1252,7 +1250,7 @@ static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, update_mmu_cache_pmd(vma, addr, pmd); } - goto out_unlock; + return; } entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); @@ -1271,11 +1269,6 @@ static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, set_pmd_at(mm, addr, pmd, entry); update_mmu_cache_pmd(vma, addr, pmd); - -out_unlock: - spin_unlock(ptl); - if (pgtable) - pte_free(mm, pgtable); } /** @@ -1294,6 +1287,7 @@ vm_fault_t vmf_insert_pfn_pmd(struct vm_fault *vmf, pfn_t pfn, bool write) struct vm_area_struct *vma = vmf->vma; pgprot_t pgprot = vma->vm_page_prot; pgtable_t pgtable = NULL; + spinlock_t *ptl; /* * If we had pmd_special, we could avoid all these restrictions, @@ -1316,12 +1310,55 @@ vm_fault_t vmf_insert_pfn_pmd(struct vm_fault *vmf, pfn_t pfn, bool write) } track_pfn_insert(vma, &pgprot, pfn); - + ptl = pmd_lock(vma->vm_mm, vmf->pmd); insert_pfn_pmd(vma, addr, vmf->pmd, pfn, pgprot, write, pgtable); + spin_unlock(ptl); + if (pgtable) + pte_free(vma->vm_mm, pgtable); + return VM_FAULT_NOPAGE; } EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd); +vm_fault_t dax_insert_pfn_pmd(struct vm_fault *vmf, pfn_t pfn, bool write) +{ + struct vm_area_struct *vma = vmf->vma; + unsigned long addr = vmf->address & PMD_MASK; + struct mm_struct *mm = vma->vm_mm; + spinlock_t *ptl; + pgtable_t pgtable = NULL; + struct folio *folio; + struct page *page; + + if (addr < vma->vm_start || addr >= vma->vm_end) + return VM_FAULT_SIGBUS; + + if (arch_needs_pgtable_deposit()) { + pgtable = pte_alloc_one(vma->vm_mm); + if (!pgtable) + return VM_FAULT_OOM; + } + + track_pfn_insert(vma, &vma->vm_page_prot, pfn); + + ptl = pmd_lock(mm, vmf->pmd); + if (pmd_none(*vmf->pmd)) { + page = pfn_t_to_page(pfn); + folio = page_folio(page); + folio_get(folio); + folio_add_file_rmap_pmd(folio, page, vma); + add_mm_counter(mm, mm_counter_file(folio), HPAGE_PMD_NR); + } + insert_pfn_pmd(vma, addr, vmf->pmd, pfn, vma->vm_page_prot, + write, pgtable); + spin_unlock(ptl); + if (pgtable) + pte_free(mm, pgtable); + + return VM_FAULT_NOPAGE; +} +EXPORT_SYMBOL_GPL(dax_insert_pfn_pmd); + #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma) {