page_alloc: make movablemem_map have higher priority

If kernelcore or movablecore is specified at the same time with
movablemem_map, movablemem_map will have higher priority to be
satisfied.  This patch will make find_zone_movable_pfns_for_nodes()
calculate zone_movable_pfn[] with the limit from zone_movable_limit[].
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Reviewed-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: Wu Jianguo <wujianguo@huawei.com>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Tested-by: Lin Feng <linfeng@cn.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/page_alloc.c

@@ -4905,9 +4905,17 @@ static void __init find_zone_movable_pfns_for_nodes(void)
 		required_kernelcore = max(required_kernelcore, corepages);
 	}
 
-	/* If kernelcore was not specified, there is no ZONE_MOVABLE */
-	if (!required_kernelcore)
+	/*
+	 * If neither kernelcore/movablecore nor movablemem_map is specified,
+	 * there is no ZONE_MOVABLE. But if movablemem_map is specified, the
+	 * start pfn of ZONE_MOVABLE has been stored in zone_movable_limit[].
+	 */
+	if (!required_kernelcore) {
+		if (movablemem_map.nr_map)
+			memcpy(zone_movable_pfn, zone_movable_limit,
+				sizeof(zone_movable_pfn));
 		goto out;
+	}
 
 	/* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
 	usable_startpfn = arch_zone_lowest_possible_pfn[movable_zone];
@@ -4937,10 +4945,24 @@ static void __init find_zone_movable_pfns_for_nodes(void)
 		for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
 			unsigned long size_pages;
 
+			/*
+			 * Find more memory for kernelcore in
+			 * [zone_movable_pfn[nid], zone_movable_limit[nid]).
+			 */
 			start_pfn = max(start_pfn, zone_movable_pfn[nid]);
 			if (start_pfn >= end_pfn)
 				continue;
 
+			if (zone_movable_limit[nid]) {
+				end_pfn = min(end_pfn, zone_movable_limit[nid]);
+				/* No range left for kernelcore in this node */
+				if (start_pfn >= end_pfn) {
+					zone_movable_pfn[nid] =
+							zone_movable_limit[nid];
+					break;
+				}
+			}
+
 			/* Account for what is only usable for kernelcore */
 			if (start_pfn < usable_startpfn) {
 				unsigned long kernel_pages;
@@ -5000,12 +5022,12 @@ static void __init find_zone_movable_pfns_for_nodes(void)
 	if (usable_nodes && required_kernelcore > usable_nodes)
 		goto restart;
 
+out:
 	/* Align start of ZONE_MOVABLE on all nids to MAX_ORDER_NR_PAGES */
 	for (nid = 0; nid < MAX_NUMNODES; nid++)
 		zone_movable_pfn[nid] =
 			roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);
 
-out:
 	/* restore the node_state */
 	node_states[N_MEMORY] = saved_node_state;
 }