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b=eiXixoTOxfrJyf+EpoEiyPUuwDFOoY9CxumkHnCC/k661PJW8cbLDdghgXgOEJxQZ6pW6Dg0ZcOGwvaZkw6xJKrjxz5qtKuNKI5IgZOty0c8WqySLl/ww9dQvLW9fhzVdIHSdAq3jXqxvm38NocuNalIvvrQa9B9mWfuyt/kCHk7+x0cd1o0ASAobdL1gRWyQTxLGf1xEs1oTZCoSM6Yt5dBb364inHi7byzESFPlCZ0lWtNT5rRjSqjYSZCsS2HGNrPH7AaMbinAs1EFlR1BYByNCilCL6i91Ssz1D0W3m9hBI1fmp4oNAQkv3Sm2oaZgDN+kLPDyw3juGm4i5mAQ== 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 MW6PR12MB7071.namprd12.prod.outlook.com (2603:10b6:303:238::8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7698.32; Thu, 27 Jun 2024 00:55:10 +0000 Received: from DS0PR12MB7726.namprd12.prod.outlook.com ([fe80::953f:2f80:90c5:67fe]) by DS0PR12MB7726.namprd12.prod.outlook.com ([fe80::953f:2f80:90c5:67fe%6]) with mapi id 15.20.7698.025; Thu, 27 Jun 2024 00:55:10 +0000 From: Alistair Popple To: dan.j.williams@intel.com, vishal.l.verma@intel.com, dave.jiang@intel.com, logang@deltatee.com, bhelgaas@google.com, jack@suse.cz, jgg@ziepe.ca Cc: 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-mm@kvack.org, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, jhubbard@nvidia.com, hch@lst.de, david@fromorbit.com, Alistair Popple Subject: [PATCH 07/13] huge_memory: Allow mappings of PUD sized pages Date: Thu, 27 Jun 2024 10:54:22 +1000 Message-ID: X-Mailer: git-send-email 2.43.0 In-Reply-To: References: X-ClientProxiedBy: SY8P300CA0020.AUSP300.PROD.OUTLOOK.COM (2603:10c6:10:29d::23) To DS0PR12MB7726.namprd12.prod.outlook.com (2603:10b6:8:130::6) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS0PR12MB7726:EE_|MW6PR12MB7071:EE_ X-MS-Office365-Filtering-Correlation-Id: 98d895e4-4e19-4e64-caa8-08dc9643cb5d 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_pud. This will map the entire PUD-sized folio and take references as it would for a normally mapped page. This is distinct from the current mechanism, vmf_insert_pfn_pud, which simply inserts a special devmap PUD 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 | 4 ++- include/linux/rmap.h | 14 +++++- mm/huge_memory.c | 108 ++++++++++++++++++++++++++++++++++++++--- mm/rmap.c | 48 ++++++++++++++++++- 4 files changed, 168 insertions(+), 6 deletions(-) diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index 2aa986a..b98a3cc 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -39,6 +39,7 @@ 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_pud(struct vm_fault *vmf, pfn_t pfn, bool write); enum transparent_hugepage_flag { TRANSPARENT_HUGEPAGE_UNSUPPORTED, @@ -106,6 +107,9 @@ extern struct kobj_attribute shmem_enabled_attr; #define HPAGE_PUD_MASK (~(HPAGE_PUD_SIZE - 1)) #define HPAGE_PUD_SIZE ((1UL) << HPAGE_PUD_SHIFT) +#define HPAGE_PUD_ORDER (HPAGE_PUD_SHIFT-PAGE_SHIFT) +#define HPAGE_PUD_NR (1<_large_mapcount); break; case RMAP_LEVEL_PMD: + case RMAP_LEVEL_PUD: atomic_inc(&folio->_entire_mapcount); atomic_inc(&folio->_large_mapcount); break; @@ -434,6 +447,7 @@ static __always_inline int __folio_try_dup_anon_rmap(struct folio *folio, atomic_add(orig_nr_pages, &folio->_large_mapcount); break; case RMAP_LEVEL_PMD: + case RMAP_LEVEL_PUD: if (PageAnonExclusive(page)) { if (unlikely(maybe_pinned)) return -EBUSY; diff --git a/mm/huge_memory.c b/mm/huge_memory.c index db7946a..e1f053e 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1283,6 +1283,70 @@ vm_fault_t vmf_insert_pfn_pud(struct vm_fault *vmf, pfn_t pfn, bool write) return VM_FAULT_NOPAGE; } EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud); + +/** + * dax_insert_pfn_pud - insert a pud size pfn backed by a normal page + * @vmf: Structure describing the fault + * @pfn: pfn of the page to insert + * @write: whether it's a write fault + * + * Return: vm_fault_t value. + */ +vm_fault_t dax_insert_pfn_pud(struct vm_fault *vmf, pfn_t pfn, bool write) +{ + struct vm_area_struct *vma = vmf->vma; + unsigned long addr = vmf->address & PUD_MASK; + pud_t *pud = vmf->pud; + pgprot_t prot = vma->vm_page_prot; + struct mm_struct *mm = vma->vm_mm; + pud_t entry; + spinlock_t *ptl; + struct folio *folio; + struct page *page; + + if (addr < vma->vm_start || addr >= vma->vm_end) + return VM_FAULT_SIGBUS; + + track_pfn_insert(vma, &prot, pfn); + + ptl = pud_lock(mm, pud); + if (!pud_none(*pud)) { + if (write) { + if (pud_pfn(*pud) != pfn_t_to_pfn(pfn)) { + WARN_ON_ONCE(!is_huge_zero_pud(*pud)); + goto out_unlock; + } + entry = pud_mkyoung(*pud); + entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma); + if (pudp_set_access_flags(vma, addr, pud, entry, 1)) + update_mmu_cache_pud(vma, addr, pud); + } + goto out_unlock; + } + + entry = pud_mkhuge(pfn_t_pud(pfn, prot)); + if (pfn_t_devmap(pfn)) + entry = pud_mkdevmap(entry); + if (write) { + entry = pud_mkyoung(pud_mkdirty(entry)); + entry = maybe_pud_mkwrite(entry, vma); + } + + page = pfn_t_to_page(pfn); + folio = page_folio(page); + folio_get(folio); + folio_add_file_rmap_pud(folio, page, vma); + add_mm_counter(mm, mm_counter_file(folio), HPAGE_PUD_NR); + + set_pud_at(mm, addr, pud, entry); + update_mmu_cache_pud(vma, addr, pud); + +out_unlock: + spin_unlock(ptl); + + return VM_FAULT_NOPAGE; +} +EXPORT_SYMBOL_GPL(dax_insert_pfn_pud); #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ void touch_pmd(struct vm_area_struct *vma, unsigned long addr, @@ -1836,7 +1900,8 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, zap_deposited_table(tlb->mm, pmd); spin_unlock(ptl); } else if (is_huge_zero_pmd(orig_pmd)) { - zap_deposited_table(tlb->mm, pmd); + if (!vma_is_dax(vma) || arch_needs_pgtable_deposit()) + zap_deposited_table(tlb->mm, pmd); spin_unlock(ptl); } else { struct folio *folio = NULL; @@ -2268,20 +2333,34 @@ spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, pud_t *pud, unsigned long addr) { + pud_t orig_pud; spinlock_t *ptl; ptl = __pud_trans_huge_lock(pud, vma); if (!ptl) return 0; - pudp_huge_get_and_clear_full(vma, addr, pud, tlb->fullmm); + orig_pud = pudp_huge_get_and_clear_full(vma, addr, pud, tlb->fullmm); tlb_remove_pud_tlb_entry(tlb, pud, addr); - if (vma_is_special_huge(vma)) { + if (!vma_is_dax(vma) && vma_is_special_huge(vma)) { spin_unlock(ptl); /* No zero page support yet */ } else { - /* No support for anonymous PUD pages yet */ - BUG(); + struct page *page = NULL; + struct folio *folio; + + /* No support for anonymous PUD pages or migration yet */ + BUG_ON(vma_is_anonymous(vma) || !pud_present(orig_pud)); + + page = pud_page(orig_pud); + folio = page_folio(page); + folio_remove_rmap_pud(folio, page, vma); + VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); + VM_BUG_ON_PAGE(!PageHead(page), page); + add_mm_counter(tlb->mm, mm_counter_file(folio), -HPAGE_PUD_NR); + + spin_unlock(ptl); + tlb_remove_page_size(tlb, page, HPAGE_PUD_SIZE); } return 1; } @@ -2289,6 +2368,8 @@ int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, unsigned long haddr) { + pud_t old_pud; + VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); VM_BUG_ON_VMA(vma->vm_start > haddr, vma); VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); @@ -2296,7 +2377,22 @@ static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, count_vm_event(THP_SPLIT_PUD); - pudp_huge_clear_flush(vma, haddr, pud); + old_pud = pudp_huge_clear_flush(vma, haddr, pud); + if (is_huge_zero_pud(old_pud)) + return; + + if (vma_is_dax(vma)) { + struct page *page = pud_page(old_pud); + struct folio *folio = page_folio(page); + + if (!folio_test_dirty(folio) && pud_dirty(old_pud)) + folio_mark_dirty(folio); + if (!folio_test_referenced(folio) && pud_young(old_pud)) + folio_set_referenced(folio); + folio_remove_rmap_pud(folio, page, vma); + folio_put(folio); + add_mm_counter(vma->vm_mm, mm_counter_file(folio), -HPAGE_PUD_NR); + } } void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, diff --git a/mm/rmap.c b/mm/rmap.c index e8fc5ec..e949e4f 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1165,6 +1165,7 @@ static __always_inline unsigned int __folio_add_rmap(struct folio *folio, atomic_add(orig_nr_pages, &folio->_large_mapcount); break; case RMAP_LEVEL_PMD: + case RMAP_LEVEL_PUD: first = atomic_inc_and_test(&folio->_entire_mapcount); if (first) { nr = atomic_add_return_relaxed(ENTIRELY_MAPPED, mapped); @@ -1306,6 +1307,12 @@ static __always_inline void __folio_add_anon_rmap(struct folio *folio, case RMAP_LEVEL_PMD: SetPageAnonExclusive(page); break; + case RMAP_LEVEL_PUD: + /* + * Keep the compiler happy, we don't support anonymous PUD mappings. + */ + WARN_ON_ONCE(1); + break; } } for (i = 0; i < nr_pages; i++) { @@ -1489,6 +1496,26 @@ void folio_add_file_rmap_pmd(struct folio *folio, struct page *page, #endif } +/** + * folio_add_file_rmap_pud - add a PUD mapping to a page range of a folio + * @folio: The folio to add the mapping to + * @page: The first page to add + * @vma: The vm area in which the mapping is added + * + * The page range of the folio is defined by [page, page + HPAGE_PUD_NR) + * + * The caller needs to hold the page table lock. + */ +void folio_add_file_rmap_pud(struct folio *folio, struct page *page, + struct vm_area_struct *vma) +{ +#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD + __folio_add_file_rmap(folio, page, HPAGE_PUD_NR, vma, RMAP_LEVEL_PUD); +#else + WARN_ON_ONCE(true); +#endif +} + static __always_inline void __folio_remove_rmap(struct folio *folio, struct page *page, int nr_pages, struct vm_area_struct *vma, enum rmap_level level) @@ -1521,6 +1548,7 @@ static __always_inline void __folio_remove_rmap(struct folio *folio, partially_mapped = nr && atomic_read(mapped); break; case RMAP_LEVEL_PMD: + case RMAP_LEVEL_PUD: atomic_dec(&folio->_large_mapcount); last = atomic_add_negative(-1, &folio->_entire_mapcount); if (last) { @@ -1615,6 +1643,26 @@ void folio_remove_rmap_pmd(struct folio *folio, struct page *page, #endif } +/** + * folio_remove_rmap_pud - remove a PUD mapping from a page range of a folio + * @folio: The folio to remove the mapping from + * @page: The first page to remove + * @vma: The vm area from which the mapping is removed + * + * The page range of the folio is defined by [page, page + HPAGE_PUD_NR) + * + * The caller needs to hold the page table lock. + */ +void folio_remove_rmap_pud(struct folio *folio, struct page *page, + struct vm_area_struct *vma) +{ +#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD + __folio_remove_rmap(folio, page, HPAGE_PUD_NR, vma, RMAP_LEVEL_PUD); +#else + WARN_ON_ONCE(true); +#endif +} + /* * @arg: enum ttu_flags will be passed to this argument */