[PATCH] skip overlap region higher level

[Wei Yang]

---
 mm/mm_init.c | 29 ++++++++++++++++++++++-------
 1 file changed, 22 insertions(+), 7 deletions(-)

diff --git a/mm/mm_init.c b/mm/mm_init.c
index 79f93f2a90cf..7a85ba58e87f 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -916,8 +916,8 @@ void __meminit memmap_init_range(unsigned long size, int nid, unsigned long zone
 		 * function.  They do not exist on hotplugged memory.
 		 */
 		if (context == MEMINIT_EARLY) {
-			if (overlap_memmap_init(zone, &pfn))
-				continue;
+			// if (overlap_memmap_init(zone, &pfn))
+			// 	continue;
 			if (defer_init(nid, pfn, zone_end_pfn)) {
 				deferred_struct_pages = true;
 				break;
@@ -974,6 +974,17 @@ static void __init memmap_init_zone_range(struct zone *zone,
 	*hole_pfn = end_pfn;
 }
 
+static bool __init region_overlapped(struct memblock_region *rgn, unsigned long zone_type)
+{
+	if (zone_type == ZONE_MOVABLE && memblock_is_mirror(rgn))
+		return true;
+
+	if (zone_type == ZONE_NORMAL && !memblock_is_mirror(rgn))
+		return true;
+
+	return false;
+}
+
 static void __init memmap_init(void)
 {
 	unsigned long start_pfn, end_pfn;
@@ -985,10 +996,15 @@ static void __init memmap_init(void)
 
 		for (j = 0; j < MAX_NR_ZONES; j++) {
 			struct zone *zone = node->node_zones + j;
+			struct memblock_region *r = &memblock.memory.regions[i];
 
 			if (!populated_zone(zone))
 				continue;
 
+			if (mirrored_kernelcore && zone_movable_pfn[nid] &&
+			    region_overlapped(r, j))
+				continue;
+
 			memmap_init_zone_range(zone, start_pfn, end_pfn,
 					       &hole_pfn);
 			zone_id = j;
@@ -1257,13 +1273,12 @@ static unsigned long __init zone_absent_pages_in_node(int nid,
 			end_pfn = clamp(memblock_region_memory_end_pfn(r),
 					zone_start_pfn, zone_end_pfn);
 
-			if (zone_type == ZONE_MOVABLE &&
-			    memblock_is_mirror(r))
-				nr_absent += end_pfn - start_pfn;
+			if (start_pfn == end_pfn)
+				continue;
 
-			if (zone_type == ZONE_NORMAL &&
-			    !memblock_is_mirror(r))
+			if (region_overlapped(r, zone_type))
 				nr_absent += end_pfn - start_pfn;
+
 		}
 	}
 
Want to confirm, the logic in zone_absent_pages_in_node() only handle
ZONE_NORMAL and ZONE_MOVABLE. So the assumption is ZONE_MOVABLE only could
overlap with ZONE_NORMAL?

When kernelcore=[nn]M is used, the "highest" populated zone is picked up to be
ZONE_MOVABLE, as indicated by find_usable_zone_for_movable(). So looks it is
possible to choose ZONE_DMA32 as ZONE_MOVABLE.

For kernelcore=mirror, we want to eliminate the complexity?

-- 
Wei Yang
Help you, Help me