On 10/6/20 2:36 PM, Anshuman Khandual wrote:
On 10/02/2020 01:46 AM, Sudarshan Rajagopalan wrote:
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 <sudar...@codeaurora.org>
Cc: Catalin Marinas <catalin.mari...@arm.com>
Cc: Will Deacon <w...@kernel.org>
Cc: Anshuman Khandual <anshuman.khand...@arm.com>
Cc: Mark Rutland <mark.rutl...@arm.com>
Cc: Logan Gunthorpe <log...@deltatee.com>
Cc: David Hildenbrand <da...@redhat.com>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Steven Price <steven.pr...@arm.com>
---
arch/arm64/mm/mmu.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
It looks good to me with Anshuman's comments fixed:
Reviewed-by: Gavin Shan <gs...@redhat.com>
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 75df62f..11f8639 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1121,8 +1121,15 @@ 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) {
+ /*
+ * fallback allocating with virtually
+ * contiguous memory for this section
+ */
Mapping is always virtually contiguous with or without huge pages.
Please drop this comment here, as it's obvious.
+ if (vmemmap_populate_basepages(addr, next,
node, NULL))
+ return -ENOMEM;
Please send in the 'altmap' instead of NULL for allocation from
device memory if and when requested.
_______________________________________________
linux-arm-kernel mailing list
linux-arm-ker...@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
