mm: compaction: use the correct type of list for free pages

Use the page->buddy_list instead of page->lru to clarify the correct type
of list for free pages.

Link: https://lkml.kernel.org/r/b21cd8e2e32b9a1d9bc9e43ebf8acaf35e87f8df.1688715750.git.baolin.wang@linux.alibaba.comSigned-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Huang, Ying <ying.huang@intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/compaction.c

@@ -1500,7 +1500,7 @@ static void fast_isolate_freepages(struct compact_control *cc)
 
 		spin_lock_irqsave(&cc->zone->lock, flags);
 		freelist = &area->free_list[MIGRATE_MOVABLE];
-		list_for_each_entry_reverse(freepage, freelist, lru) {
+		list_for_each_entry_reverse(freepage, freelist, buddy_list) {
 			unsigned long pfn;
 
 			order_scanned++;
@@ -1883,7 +1883,7 @@ static unsigned long fast_find_migrateblock(struct compact_control *cc)
 
 		spin_lock_irqsave(&cc->zone->lock, flags);
 		freelist = &area->free_list[MIGRATE_MOVABLE];
-		list_for_each_entry(freepage, freelist, lru) {
+		list_for_each_entry(freepage, freelist, buddy_list) {
 			unsigned long free_pfn;
 
 			if (nr_scanned++ >= limit) {