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authorSudarshan Rajagopalan <[email protected]>2020-10-14 17:51:23 -0700
committerCatalin Marinas <[email protected]>2020-11-17 18:21:01 +0000
commit9f84f39f5515fd412398a1019e3f50ac3ab51a80 (patch)
treea9aeecf9aa199e04f8729817aaff6e7a07fe9faf
parent0edaee42eb8c0f3b767ec3c51bee4a3855aa2555 (diff)
arm64/mm: add fallback option to allocate virtually contiguous memory
When section mappings are enabled, we allocate vmemmap pages from physically continuous memory of size PMD_SIZE using vmemmap_alloc_block_buf(). Section mappings are good to reduce TLB pressure. But when system is highly fragmented and memory blocks are being hot-added at runtime, its possible that such physically continuous memory allocations can fail. Rather than failing the memory hot-add procedure, add a fallback option to allocate vmemmap pages from discontinuous pages using vmemmap_populate_basepages(). Signed-off-by: Sudarshan Rajagopalan <[email protected]> Reviewed-by: Gavin Shan <[email protected]> Reviewed-by: Anshuman Khandual <[email protected]> Acked-by: Will Deacon <[email protected]> Cc: Will Deacon <[email protected]> Cc: Anshuman Khandual <[email protected]> Cc: Mark Rutland <[email protected]> Cc: Logan Gunthorpe <[email protected]> Cc: David Hildenbrand <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Steven Price <[email protected]> Link: https://lore.kernel.org/r/d6c06f2ef39bbe6c715b2f6db76eb16155fdcee6.1602722808.git.sudaraja@codeaurora.org Signed-off-by: Catalin Marinas <[email protected]>
-rw-r--r--arch/arm64/mm/mmu.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 1c0f3e02f731..a773d2a1a2bf 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1132,8 +1132,11 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
void *p = NULL;
p = vmemmap_alloc_block_buf(PMD_SIZE, node, altmap);
- if (!p)
- return -ENOMEM;
+ if (!p) {
+ if (vmemmap_populate_basepages(addr, next, node, altmap))
+ return -ENOMEM;
+ continue;
+ }
pmd_set_huge(pmdp, __pa(p), __pgprot(PROT_SECT_NORMAL));
} else