mm/page_alloc.c: change the array-length to MIGRATE_PCPTYPES

Earlier, in commit 1dd214b8f21c ("mm: page_alloc: avoid merging
non-fallbackable pageblocks with others"), migrate type MIGRATE_CMA and
MIGRATE_ISOLATE are removed from fallbacks list since they are never used.

Later on, in commit ("aa02d3c174ab mm/page_alloc: reduce fallbacks to
(MIGRATE_PCPTYPES - 1)"), the array column size is reduced to
'MIGRATE_PCPTYPES - 1'. In fact, the array row size need be reduced to
MIGRATE_PCPTYPES too since it's only covering rows of the number
MIGRATE_PCPTYPES. Even though the current code has handled cases
when the migratetype is CMA, HIGHATOMIC and MEMORY_ISOLATION, making
the row size right is still good to avoid future error and confusion.

Link: https://lkml.kernel.org/r/20240326061134.1055295-8-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: "Mike Rapoport (IBM)" <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 875cec8c77089ff1d0d47dc0628bd3b94efc696c..47ab0297838a66cb756b332127da34129c2983d6 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1542,7 +1542,7 @@ struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
  *
  * The other migratetypes do not have fallbacks.
  */
-static int fallbacks[MIGRATE_TYPES][MIGRATE_PCPTYPES - 1] = {
+static int fallbacks[MIGRATE_PCPTYPES][MIGRATE_PCPTYPES - 1] = {
        [MIGRATE_UNMOVABLE]   = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE   },
        [MIGRATE_MOVABLE]     = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE },
        [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE,   MIGRATE_MOVABLE   },