path: root/mm/sparse-vmemmap.c
diff options
authorAnshuman Khandual <>2020-08-06 23:23:19 -0700
committerLinus Torvalds <>2020-08-07 11:33:27 -0700
commit1d9cfee7535c213038a615f112c900c2d0ba8f54 (patch)
tree232ef6d3e0b1c67364c4e2507b5ba332929add2c /mm/sparse-vmemmap.c
parent56f3547bfa4d361148aa748ccb86073bc57f5e6c (diff)
mm/sparsemem: enable vmem_altmap support in vmemmap_populate_basepages()
Patch series "arm64: Enable vmemmap mapping from device memory", v4. This series enables vmemmap backing memory allocation from device memory ranges on arm64. But before that, it enables vmemmap_populate_basepages() and vmemmap_alloc_block_buf() to accommodate struct vmem_altmap based alocation requests. This patch (of 3): vmemmap_populate_basepages() is used across platforms to allocate backing memory for vmemmap mapping. This is used as a standard default choice or as a fallback when intended huge pages allocation fails. This just creates entire vmemmap mapping with base pages (PAGE_SIZE). On arm64 platforms, vmemmap_populate_basepages() is called instead of the platform specific vmemmap_populate() when ARM64_SWAPPER_USES_SECTION_MAPS is not enabled as in case for ARM64_16K_PAGES and ARM64_64K_PAGES configs. At present vmemmap_populate_basepages() does not support allocating from driver defined struct vmem_altmap while trying to create vmemmap mapping for a device memory range. It prevents ARM64_16K_PAGES and ARM64_64K_PAGES configs on arm64 from supporting device memory with vmemap_altmap request. This enables vmem_altmap support in vmemmap_populate_basepages() unlocking device memory allocation for vmemap mapping on arm64 platforms with 16K or 64K base page configs. Each architecture should evaluate and decide on subscribing device memory based base page allocation through vmemmap_populate_basepages(). Hence lets keep it disabled on all archs in order to preserve the existing semantics. A subsequent patch enables it on arm64. Signed-off-by: Anshuman Khandual <> Signed-off-by: Andrew Morton <> Tested-by: Jia He <> Reviewed-by: David Hildenbrand <> Acked-by: Will Deacon <> Acked-by: Catalin Marinas <> Cc: Mark Rutland <> Cc: Paul Walmsley <> Cc: Palmer Dabbelt <> Cc: Tony Luck <> Cc: Fenghua Yu <> Cc: Dave Hansen <> Cc: Andy Lutomirski <> Cc: Peter Zijlstra <> Cc: Thomas Gleixner <> Cc: Ingo Molnar <> Cc: Mike Rapoport <> Cc: Michal Hocko <> Cc: "Matthew Wilcox (Oracle)" <> Cc: "Kirill A. Shutemov" <> Cc: Dan Williams <> Cc: Pavel Tatashin <> Cc: Benjamin Herrenschmidt <> Cc: Borislav Petkov <> Cc: "H. Peter Anvin" <> Cc: Hsin-Yi Wang <> Cc: Jonathan Corbet <> Cc: Michael Ellerman <> Cc: Paul Mackerras <> Cc: Robin Murphy <> Cc: Steve Capper <> Cc: Yu Zhao <> Link: Link: Signed-off-by: Linus Torvalds <>
Diffstat (limited to 'mm/sparse-vmemmap.c')
1 files changed, 11 insertions, 5 deletions
diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
index 0db7738d76e9..ceed10dec31e 100644
--- a/mm/sparse-vmemmap.c
+++ b/mm/sparse-vmemmap.c
@@ -139,12 +139,18 @@ void __meminit vmemmap_verify(pte_t *pte, int node,
start, end - 1);
-pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node)
+pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node,
+ struct vmem_altmap *altmap)
pte_t *pte = pte_offset_kernel(pmd, addr);
if (pte_none(*pte)) {
pte_t entry;
- void *p = vmemmap_alloc_block_buf(PAGE_SIZE, node);
+ void *p;
+ if (altmap)
+ p = altmap_alloc_block_buf(PAGE_SIZE, altmap);
+ else
+ p = vmemmap_alloc_block_buf(PAGE_SIZE, node);
if (!p)
return NULL;
entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL);
@@ -212,8 +218,8 @@ pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node)
return pgd;
-int __meminit vmemmap_populate_basepages(unsigned long start,
- unsigned long end, int node)
+int __meminit vmemmap_populate_basepages(unsigned long start, unsigned long end,
+ int node, struct vmem_altmap *altmap)
unsigned long addr = start;
pgd_t *pgd;
@@ -235,7 +241,7 @@ int __meminit vmemmap_populate_basepages(unsigned long start,
pmd = vmemmap_pmd_populate(pud, addr, node);
if (!pmd)
return -ENOMEM;
- pte = vmemmap_pte_populate(pmd, addr, node);
+ pte = vmemmap_pte_populate(pmd, addr, node, altmap);
if (!pte)
return -ENOMEM;
vmemmap_verify(pte, node, addr, addr + PAGE_SIZE);