[PATCH] mm: ignore nomap memory during mirror init

[Wupeng Ma]

When memory mirroring is enabled, the BIOS may reserve memory regions
at the start of the physical address space without the MR flag. This will
lead to zone_movable_pfn to be updated to the start of these reserved
regions, resulting in subsequent mirrored memory being ignored.

Here is the log with efi=debug enabled:
  efi:   0x084004000000-0x0842bf37ffff [Conventional|   |  |MR|...|WB|WT|WC|  ]
  efi:   0x0842bf380000-0x0842c21effff [Loader Code |   |  |MR|...|WB|WT|WC|  ]
  efi:   0x0842c21f0000-0x0847ffffffff [Conventional|   |  |MR|...|WB|WT|WC|  ]
  efi:   0x085000000000-0x085fffffffff [Conventional|   |  |  |...|WB|WT|WC|  ]
...
  efi:   0x084000000000-0x084003ffffff [Reserved    |   |  |  |...|WB|WT|WC|  ]

Since this kind of memory can not be used by kernel. ignore nomap memory to fix
this issue.

Signed-off-by: Wupeng Ma <mawupeng1@xxxxxxxxxx>
---
 mm/mm_init.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/mm_init.c b/mm/mm_init.c
index f2944748f526..1c36518f0fe4 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -405,7 +405,7 @@ static void __init find_zone_movable_pfns_for_nodes(void)
 		}
 
 		for_each_mem_region(r) {
-			if (memblock_is_mirror(r))
+			if (memblock_is_mirror(r) || memblock_is_nomap(r))
 				continue;
 
 			nid = memblock_get_region_node(r);
-- 
2.43.0