This 'commit 86588296acbf ("fdt: Properly handle "no-map" field in the
memory region")' is keeping the no-map regions in memblock.memory with
MEMBLOCK_NOMAP flag set to use no-map memory for EFI using memblock api's,
but during the initialization sparse_init mark all memblock.memory as
present using for_each_mem_pfn_range, which is creating the memmap for
no-map memblock regions. To avoid it skiping the memblock.memory regions
set with MEMBLOCK_NOMAP set and with this change we will be able to save
~11MB memory for ~612MB carve out.
With change:
[ 0.000000] memblock_alloc_exact_nid_raw: 115343360 bytes align=0x200000 nid=0 from=0x0000000080000000 max_addr=0x0000000000000000 sparse_buffer_init+0x60/0x8c
[ 0.000000] memblock_reserve: [0x0000000932c00000-0x00000009399fffff] memblock_alloc_range_nid+0xbc/0x1a0
[ 0.000000] On node 0 totalpages: 1627824
[ 0.000000] DMA32 zone: 5383 pages used for memmap
[ 0.000000] Normal zone: 20052 pages used for memmap
Without change:
[ 0.000000] memblock_alloc_exact_nid_raw: 117440512 bytes align=0x200000 nid=0 from=0x0000000080000000 max_addr=0x0000000000000000 sparse_buffer_init+0x60/0x8c
[ 0.000000] memblock_reserve: [0x0000000932a00000-0x00000009399fffff] memblock_alloc_range_nid+0xbc/0x1a0
[ 0.000000] On node 0 totalpages: 1788416
[ 0.000000] DMA32 zone: 8192 pages used for memmap
[ 0.000000] Normal zone: 20052 pages used for memmap.
Signed-off-by: Faiyaz Mohammed <quic_faiyazm@xxxxxxxxxxx>
---
mm/memblock.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/mm/memblock.c b/mm/memblock.c
index 2270e3c..a4fde9d 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -1175,8 +1175,13 @@ void __init_memblock __next_mem_pfn_range(int *idx, int nid,
r = &type->regions[*idx];
r_nid = memblock_get_region_node(r);
+ /* If memblock region is nomap then skip the region. */
+ if (memblock_is_nomap(r))
+ continue;
+
if (PFN_UP(r->base) >= PFN_DOWN(r->base + r->size))
continue;
+
if (nid == MAX_NUMNODES || nid == r_nid)
break;
}
--
2.7.4
