From 508758960b8d89fa464abce2f9897973c8e8d4f0 Mon Sep 17 00:00:00 2001 From: Chuanhua Han Date: Wed, 29 May 2024 20:28:24 +1200 Subject: mm: swap: entirely map large folios found in swapcache When a large folio is found in the swapcache, the current implementation requires calling do_swap_page() nr_pages times, resulting in nr_pages page faults. This patch opts to map the entire large folio at once to minimize page faults. Additionally, redundant checks and early exits for ARM64 MTE restoring are removed. Link: https://lkml.kernel.org/r/20240529082824.150954-7-21cnbao@gmail.com Signed-off-by: Chuanhua Han Co-developed-by: Barry Song Signed-off-by: Barry Song Reviewed-by: Ryan Roberts Reviewed-by: "Huang, Ying" Cc: Andreas Larsson Cc: Baolin Wang Cc: Chris Li Cc: Christoph Hellwig Cc: David Hildenbrand Cc: "David S. Miller" Cc: Gao Xiang Cc: Hugh Dickins Cc: Johannes Weiner Cc: Kairui Song Cc: Khalid Aziz Cc: Len Brown Cc: Matthew Wilcox (Oracle) Cc: Pavel Machek Cc: "Rafael J. Wysocki" Cc: Suren Baghdasaryan Cc: Yosry Ahmed Cc: Yu Zhao Cc: Zi Yan Signed-off-by: Andrew Morton --- mm/memory.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 48 insertions(+), 11 deletions(-) (limited to 'mm/memory.c') diff --git a/mm/memory.c b/mm/memory.c index 2aac2000f0de..70d42483cd46 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4010,6 +4010,10 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) pte_t pte; vm_fault_t ret = 0; void *shadow = NULL; + int nr_pages; + unsigned long page_idx; + unsigned long address; + pte_t *ptep; if (!pte_unmap_same(vmf)) goto out; @@ -4208,6 +4212,38 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) goto out_nomap; } + nr_pages = 1; + page_idx = 0; + address = vmf->address; + ptep = vmf->pte; + if (folio_test_large(folio) && folio_test_swapcache(folio)) { + int nr = folio_nr_pages(folio); + unsigned long idx = folio_page_idx(folio, page); + unsigned long folio_start = address - idx * PAGE_SIZE; + unsigned long folio_end = folio_start + nr * PAGE_SIZE; + pte_t *folio_ptep; + pte_t folio_pte; + + if (unlikely(folio_start < max(address & PMD_MASK, vma->vm_start))) + goto check_folio; + if (unlikely(folio_end > pmd_addr_end(address, vma->vm_end))) + goto check_folio; + + folio_ptep = vmf->pte - idx; + folio_pte = ptep_get(folio_ptep); + if (!pte_same(folio_pte, pte_move_swp_offset(vmf->orig_pte, -idx)) || + swap_pte_batch(folio_ptep, nr, folio_pte) != nr) + goto check_folio; + + page_idx = idx; + address = folio_start; + ptep = folio_ptep; + nr_pages = nr; + entry = folio->swap; + page = &folio->page; + } + +check_folio: /* * PG_anon_exclusive reuses PG_mappedtodisk for anon pages. A swap pte * must never point at an anonymous page in the swapcache that is @@ -4267,12 +4303,12 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) * We're already holding a reference on the page but haven't mapped it * yet. */ - swap_free(entry); + swap_free_nr(entry, nr_pages); if (should_try_to_free_swap(folio, vma, vmf->flags)) folio_free_swap(folio); - inc_mm_counter(vma->vm_mm, MM_ANONPAGES); - dec_mm_counter(vma->vm_mm, MM_SWAPENTS); + add_mm_counter(vma->vm_mm, MM_ANONPAGES, nr_pages); + add_mm_counter(vma->vm_mm, MM_SWAPENTS, -nr_pages); pte = mk_pte(page, vma->vm_page_prot); /* @@ -4289,27 +4325,28 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) } rmap_flags |= RMAP_EXCLUSIVE; } - flush_icache_page(vma, page); + folio_ref_add(folio, nr_pages - 1); + flush_icache_pages(vma, page, nr_pages); if (pte_swp_soft_dirty(vmf->orig_pte)) pte = pte_mksoft_dirty(pte); if (pte_swp_uffd_wp(vmf->orig_pte)) pte = pte_mkuffd_wp(pte); - vmf->orig_pte = pte; + vmf->orig_pte = pte_advance_pfn(pte, page_idx); /* ksm created a completely new copy */ if (unlikely(folio != swapcache && swapcache)) { - folio_add_new_anon_rmap(folio, vma, vmf->address); + folio_add_new_anon_rmap(folio, vma, address); folio_add_lru_vma(folio, vma); } else { - folio_add_anon_rmap_pte(folio, page, vma, vmf->address, + folio_add_anon_rmap_ptes(folio, page, nr_pages, vma, address, rmap_flags); } VM_BUG_ON(!folio_test_anon(folio) || (pte_write(pte) && !PageAnonExclusive(page))); - set_pte_at(vma->vm_mm, vmf->address, vmf->pte, pte); - arch_do_swap_page_nr(vma->vm_mm, vma, vmf->address, - pte, vmf->orig_pte, 1); + set_ptes(vma->vm_mm, address, ptep, pte, nr_pages); + arch_do_swap_page_nr(vma->vm_mm, vma, address, + pte, pte, nr_pages); folio_unlock(folio); if (folio != swapcache && swapcache) { @@ -4333,7 +4370,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) } /* No need to invalidate - it was non-present before */ - update_mmu_cache_range(vmf, vma, vmf->address, vmf->pte, 1); + update_mmu_cache_range(vmf, vma, address, ptep, nr_pages); unlock: if (vmf->pte) pte_unmap_unlock(vmf->pte, vmf->ptl); -- cgit v1.2.3