From 415c84498fc4633666522aec0df7880f4b700210 Mon Sep 17 00:00:00 2001 From: Yin Fengwei Date: Wed, 2 Aug 2023 16:14:04 +0100 Subject: [PATCH] mm: convert do_set_pte() to set_pte_range() set_pte_range() allows to setup page table entries for a specific range. It takes advantage of batched rmap update for large folio. It now takes care of calling update_mmu_cache_range(). Link: https://lkml.kernel.org/r/20230802151406.3735276-37-willy@infradead.org Signed-off-by: Yin Fengwei Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton --- Documentation/filesystems/locking.rst | 2 +- include/linux/mm.h | 3 ++- mm/filemap.c | 3 +-- mm/memory.c | 37 +++++++++++++++++---------- 4 files changed, 28 insertions(+), 17 deletions(-) diff --git a/Documentation/filesystems/locking.rst b/Documentation/filesystems/locking.rst index ed148919e11a..211a03053992 100644 --- a/Documentation/filesystems/locking.rst +++ b/Documentation/filesystems/locking.rst @@ -661,7 +661,7 @@ locked. The VM will unlock the page. Filesystem should find and map pages associated with offsets from "start_pgoff" till "end_pgoff". ->map_pages() is called with the RCU lock held and must not block. If it's not possible to reach a page without blocking, -filesystem should skip it. Filesystem should use do_set_pte() to setup +filesystem should skip it. Filesystem should use set_pte_range() to setup page table entry. Pointer to entry associated with the page is passed in "pte" field in vm_fault structure. Pointers to entries for other offsets should be calculated relative to "pte". diff --git a/include/linux/mm.h b/include/linux/mm.h index 608e26728bb6..63edff994c32 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1346,7 +1346,8 @@ static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) } vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page); -void do_set_pte(struct vm_fault *vmf, struct page *page, unsigned long addr); +void set_pte_range(struct vm_fault *vmf, struct folio *folio, + struct page *page, unsigned int nr, unsigned long addr); vm_fault_t finish_fault(struct vm_fault *vmf); vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf); diff --git a/mm/filemap.c b/mm/filemap.c index bdc1e0b811bf..c06e9d331416 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -3501,8 +3501,7 @@ static vm_fault_t filemap_map_folio_range(struct vm_fault *vmf, ret = VM_FAULT_NOPAGE; ref_count++; - do_set_pte(vmf, page, addr); - update_mmu_cache(vma, addr, vmf->pte); + set_pte_range(vmf, folio, page, 1, addr); } while (vmf->pte++, page++, addr += PAGE_SIZE, ++count < nr_pages); /* Restore the vmf->pte */ diff --git a/mm/memory.c b/mm/memory.c index 8acb5a0faf98..6644444cfff3 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4333,15 +4333,24 @@ vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page) } #endif -void do_set_pte(struct vm_fault *vmf, struct page *page, unsigned long addr) +/** + * set_pte_range - Set a range of PTEs to point to pages in a folio. + * @vmf: Fault decription. + * @folio: The folio that contains @page. + * @page: The first page to create a PTE for. + * @nr: The number of PTEs to create. + * @addr: The first address to create a PTE for. + */ +void set_pte_range(struct vm_fault *vmf, struct folio *folio, + struct page *page, unsigned int nr, unsigned long addr) { struct vm_area_struct *vma = vmf->vma; bool uffd_wp = vmf_orig_pte_uffd_wp(vmf); bool write = vmf->flags & FAULT_FLAG_WRITE; - bool prefault = vmf->address != addr; + bool prefault = in_range(vmf->address, addr, nr * PAGE_SIZE); pte_t entry; - flush_icache_page(vma, page); + flush_icache_pages(vma, page, nr); entry = mk_pte(page, vma->vm_page_prot); if (prefault && arch_wants_old_prefaulted_pte()) @@ -4355,14 +4364,18 @@ void do_set_pte(struct vm_fault *vmf, struct page *page, unsigned long addr) entry = pte_mkuffd_wp(entry); /* copy-on-write page */ if (write && !(vma->vm_flags & VM_SHARED)) { - inc_mm_counter(vma->vm_mm, MM_ANONPAGES); - page_add_new_anon_rmap(page, vma, addr); - lru_cache_add_inactive_or_unevictable(page, vma); + add_mm_counter(vma->vm_mm, MM_ANONPAGES, nr); + VM_BUG_ON_FOLIO(nr != 1, folio); + folio_add_new_anon_rmap(folio, vma, addr); + folio_add_lru_vma(folio, vma); } else { - inc_mm_counter(vma->vm_mm, mm_counter_file(page)); - page_add_file_rmap(page, vma, false); + add_mm_counter(vma->vm_mm, mm_counter_file(page), nr); + folio_add_file_rmap_range(folio, page, nr, vma, false); } - set_pte_at(vma->vm_mm, addr, vmf->pte, entry); + set_ptes(vma->vm_mm, addr, vmf->pte, entry, nr); + + /* no need to invalidate: a not-present page won't be cached */ + update_mmu_cache_range(vmf, vma, addr, vmf->pte, nr); } static bool vmf_pte_changed(struct vm_fault *vmf) @@ -4430,11 +4443,9 @@ vm_fault_t finish_fault(struct vm_fault *vmf) /* Re-check under ptl */ if (likely(!vmf_pte_changed(vmf))) { - do_set_pte(vmf, page, vmf->address); - - /* no need to invalidate: a not-present page won't be cached */ - update_mmu_cache(vma, vmf->address, vmf->pte); + struct folio *folio = page_folio(page); + set_pte_range(vmf, folio, page, 1, vmf->address); ret = 0; } else { update_mmu_tlb(vma, vmf->address, vmf->pte);