[RFC PATCH 15/26] mm: compaction: simplify free block check in suitable_migration_target()

Johannes Weiner
2023-04-18T19:20:51Z

Free page blocks are now marked MIGRATE_FREE. Consult that directly.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
---
mm/compaction.c | 15 +++++----------
1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/mm/compaction.c b/mm/compaction.c
index a2280001eea3..b9eed0d43403 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1281,22 +1281,17 @@ static bool suitable_migration_source(struct compact_control *cc,
static bool suitable_migration_target(struct compact_control *cc,
struct page *page)
{
+ int mt = get_pageblock_migratetype(page);
+
/* If the page is a large free page, then disallow migration */
- if (PageBuddy(page)) {
- /*
- * We are checking page_order without zone->lock taken. But
- * the only small danger is that we skip a potentially suitable
- * pageblock, so it's not worth to check order for valid range.
- */
- if (buddy_order_unsafe(page) >= pageblock_order)
- return false;
- }
+ if (mt == MIGRATE_FREE)
+ return false;

if (cc->ignore_block_suitable)
return true;

/* If the block is MIGRATE_MOVABLE or MIGRATE_CMA, allow migration */
- if (is_migrate_movable(get_pageblock_migratetype(page)))
+ if (is_migrate_movable(mt))
return true;

/* Otherwise skip the block */
--
2.39.2