From: Mike Rapoport <redacted>

numa_clear_kernel_node_hotplug() function first traverses numa_meminfo
regions to set node ID in memblock.reserved and than traverses
memblock.reserved to update reserved_nodemask to include node IDs that were
set in the first loop.

Remove redundant traversal over memblock.reserved and update
reserved_nodemask while iterating over numa_meminfo.

Signed-off-by: Mike Rapoport <redacted>
---
 arch/x86/mm/numa.c | 26 ++++++++++----------------
 1 file changed, 10 insertions(+), 16 deletions(-)

diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index 8ee952038c80..4078abd33938 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c

@@ -498,31 +498,25 @@ static void __init numa_clear_kernel_node_hotplug(void)
 	 * and use those ranges to set the nid in memblock.reserved.
 	 * This will split up the memblock regions along node
 	 * boundaries and will set the node IDs as well.
+	 *
+	 * The nid will also be set in reserved_nodemask which is later
+	 * used to clear MEMBLOCK_HOTPLUG flag.
+	 *
+	 * [ Note, when booting with mem=nn[kMG] or in a kdump kernel,
+	 *   numa_meminfo might not include all memblock.reserved
+	 *   memory ranges, because quirks such as trim_snb_memory()
+	 *   reserve specific pages for Sandy Bridge graphics.
+	 *   These ranges will remain with nid == MAX_NUMNODES. ]
 	 */
 	for (i = 0; i < numa_meminfo.nr_blks; i++) {
 		struct numa_memblk *mb = numa_meminfo.blk + i;
 		int ret;
 
 		ret = memblock_set_node(mb->start, mb->end - mb->start, &memblock.reserved, mb->nid);
+		node_set(mb->nid, reserved_nodemask);