From eee07935bb52a03561d53ccc5cecf12f2faeb396 Mon Sep 17 00:00:00 2001 From: Anshuman Khandual Date: Thu, 6 Aug 2020 23:23:29 -0700 Subject: [PATCH] arm64/mm: enable vmem_altmap support for vmemmap mappings Device memory ranges when getting hot added into ZONE_DEVICE, might require their vmemmap mapping's backing memory to be allocated from their own range instead of consuming system memory. This prevents large system memory usage for potentially large device memory ranges. Device driver communicates this request via vmem_altmap structure. Architecture needs to take this request into account while creating and tearing down vemmmap mappings. This enables vmem_altmap support in vmemmap_populate() and vmemmap_free() which includes vmemmap_populate_basepages() used for ARM64_16K_PAGES and ARM64_64K_PAGES configs. Signed-off-by: Anshuman Khandual Signed-off-by: Andrew Morton Tested-by: Jia He Reviewed-by: Catalin Marinas Cc: Will Deacon Cc: Mark Rutland Cc: Steve Capper Cc: David Hildenbrand Cc: Yu Zhao Cc: Hsin-Yi Wang Cc: Thomas Gleixner Cc: Andy Lutomirski Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Dan Williams Cc: Dave Hansen Cc: Fenghua Yu Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jonathan Corbet Cc: "Kirill A. Shutemov" Cc: "Matthew Wilcox (Oracle)" Cc: Michael Ellerman Cc: Michal Hocko Cc: Mike Rapoport Cc: Palmer Dabbelt Cc: Paul Mackerras Cc: Paul Walmsley Cc: Pavel Tatashin Cc: Peter Zijlstra Cc: Robin Murphy Cc: Tony Luck Link: http://lkml.kernel.org/r/1594004178-8861-4-git-send-email-anshuman.khandual@arm.com Signed-off-by: Linus Torvalds --- arch/arm64/mm/mmu.c | 58 +++++++++++++++++++++++++++++---------------- 1 file changed, 38 insertions(+), 20 deletions(-) diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index f3d9ff323c8f..75df62fea1b6 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -761,15 +761,20 @@ int kern_addr_valid(unsigned long addr) } #ifdef CONFIG_MEMORY_HOTPLUG -static void free_hotplug_page_range(struct page *page, size_t size) +static void free_hotplug_page_range(struct page *page, size_t size, + struct vmem_altmap *altmap) { - WARN_ON(PageReserved(page)); - free_pages((unsigned long)page_address(page), get_order(size)); + if (altmap) { + vmem_altmap_free(altmap, size >> PAGE_SHIFT); + } else { + WARN_ON(PageReserved(page)); + free_pages((unsigned long)page_address(page), get_order(size)); + } } static void free_hotplug_pgtable_page(struct page *page) { - free_hotplug_page_range(page, PAGE_SIZE); + free_hotplug_page_range(page, PAGE_SIZE, NULL); } static bool pgtable_range_aligned(unsigned long start, unsigned long end, @@ -792,7 +797,8 @@ static bool pgtable_range_aligned(unsigned long start, unsigned long end, } static void unmap_hotplug_pte_range(pmd_t *pmdp, unsigned long addr, - unsigned long end, bool free_mapped) + unsigned long end, bool free_mapped, + struct vmem_altmap *altmap) { pte_t *ptep, pte; @@ -806,12 +812,14 @@ static void unmap_hotplug_pte_range(pmd_t *pmdp, unsigned long addr, pte_clear(&init_mm, addr, ptep); flush_tlb_kernel_range(addr, addr + PAGE_SIZE); if (free_mapped) - free_hotplug_page_range(pte_page(pte), PAGE_SIZE); + free_hotplug_page_range(pte_page(pte), + PAGE_SIZE, altmap); } while (addr += PAGE_SIZE, addr < end); } static void unmap_hotplug_pmd_range(pud_t *pudp, unsigned long addr, - unsigned long end, bool free_mapped) + unsigned long end, bool free_mapped, + struct vmem_altmap *altmap) { unsigned long next; pmd_t *pmdp, pmd; @@ -834,16 +842,17 @@ static void unmap_hotplug_pmd_range(pud_t *pudp, unsigned long addr, flush_tlb_kernel_range(addr, addr + PAGE_SIZE); if (free_mapped) free_hotplug_page_range(pmd_page(pmd), - PMD_SIZE); + PMD_SIZE, altmap); continue; } WARN_ON(!pmd_table(pmd)); - unmap_hotplug_pte_range(pmdp, addr, next, free_mapped); + unmap_hotplug_pte_range(pmdp, addr, next, free_mapped, altmap); } while (addr = next, addr < end); } static void unmap_hotplug_pud_range(p4d_t *p4dp, unsigned long addr, - unsigned long end, bool free_mapped) + unsigned long end, bool free_mapped, + struct vmem_altmap *altmap) { unsigned long next; pud_t *pudp, pud; @@ -866,16 +875,17 @@ static void unmap_hotplug_pud_range(p4d_t *p4dp, unsigned long addr, flush_tlb_kernel_range(addr, addr + PAGE_SIZE); if (free_mapped) free_hotplug_page_range(pud_page(pud), - PUD_SIZE); + PUD_SIZE, altmap); continue; } WARN_ON(!pud_table(pud)); - unmap_hotplug_pmd_range(pudp, addr, next, free_mapped); + unmap_hotplug_pmd_range(pudp, addr, next, free_mapped, altmap); } while (addr = next, addr < end); } static void unmap_hotplug_p4d_range(pgd_t *pgdp, unsigned long addr, - unsigned long end, bool free_mapped) + unsigned long end, bool free_mapped, + struct vmem_altmap *altmap) { unsigned long next; p4d_t *p4dp, p4d; @@ -888,16 +898,24 @@ static void unmap_hotplug_p4d_range(pgd_t *pgdp, unsigned long addr, continue; WARN_ON(!p4d_present(p4d)); - unmap_hotplug_pud_range(p4dp, addr, next, free_mapped); + unmap_hotplug_pud_range(p4dp, addr, next, free_mapped, altmap); } while (addr = next, addr < end); } static void unmap_hotplug_range(unsigned long addr, unsigned long end, - bool free_mapped) + bool free_mapped, struct vmem_altmap *altmap) { unsigned long next; pgd_t *pgdp, pgd; + /* + * altmap can only be used as vmemmap mapping backing memory. + * In case the backing memory itself is not being freed, then + * altmap is irrelevant. Warn about this inconsistency when + * encountered. + */ + WARN_ON(!free_mapped && altmap); + do { next = pgd_addr_end(addr, end); pgdp = pgd_offset_k(addr); @@ -906,7 +924,7 @@ static void unmap_hotplug_range(unsigned long addr, unsigned long end, continue; WARN_ON(!pgd_present(pgd)); - unmap_hotplug_p4d_range(pgdp, addr, next, free_mapped); + unmap_hotplug_p4d_range(pgdp, addr, next, free_mapped, altmap); } while (addr = next, addr < end); } @@ -1070,7 +1088,7 @@ static void free_empty_tables(unsigned long addr, unsigned long end, int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, struct vmem_altmap *altmap) { - return vmemmap_populate_basepages(start, end, node, NULL); + return vmemmap_populate_basepages(start, end, node, altmap); } #else /* !ARM64_SWAPPER_USES_SECTION_MAPS */ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, @@ -1102,7 +1120,7 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, if (pmd_none(READ_ONCE(*pmdp))) { void *p = NULL; - p = vmemmap_alloc_block_buf(PMD_SIZE, node, NULL); + p = vmemmap_alloc_block_buf(PMD_SIZE, node, altmap); if (!p) return -ENOMEM; @@ -1120,7 +1138,7 @@ void vmemmap_free(unsigned long start, unsigned long end, #ifdef CONFIG_MEMORY_HOTPLUG WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END)); - unmap_hotplug_range(start, end, true); + unmap_hotplug_range(start, end, true, altmap); free_empty_tables(start, end, VMEMMAP_START, VMEMMAP_END); #endif } @@ -1411,7 +1429,7 @@ static void __remove_pgd_mapping(pgd_t *pgdir, unsigned long start, u64 size) WARN_ON(pgdir != init_mm.pgd); WARN_ON((start < PAGE_OFFSET) || (end > PAGE_END)); - unmap_hotplug_range(start, end, false); + unmap_hotplug_range(start, end, false, NULL); free_empty_tables(start, end, PAGE_OFFSET, PAGE_END); } -- 2.39.5