From: Muchun Song
mainline inclusion
from mainline-v5.11-rc1
commit 2484be0f88dc6c9670362d51f6a04f2da0626b50
category: bugfix
issue: #I3ZXZF
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
-----------------------------------------------
A max order page has no buddy page and never merges to another order. So
isolating and then freeing it is pointless.
Link: https://lkml.kernel.org/r/20201202122114.75316-1-songmuchun@bytedance.com
Fixes: 3c605096d315 ("mm/page_alloc: restrict max order of merging on isolated pageblock")
Signed-off-by: Muchun Song
Reviewed-by: Andrew Morton
Acked-by: Vlastimil Babka
Reviewed-by: David Hildenbrand
Reviewed-by: Oscar Salvador
Cc: Joonsoo Kim
Cc: Matthew Wilcox
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
Signed-off-by: Tong Tiangen
Reviewed-by: Chen Wandun
Signed-off-by: Chen Jun
Signed-off-by: Yu Changchun
---
mm/page_isolation.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index abbf42214485..756d1542f2c8 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -89,7 +89,7 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype)
*/
if (PageBuddy(page)) {
order = buddy_order(page);
- if (order >= pageblock_order) {
+ if (order >= pageblock_order && order < MAX_ORDER - 1) {
pfn = page_to_pfn(page);
buddy_pfn = __find_buddy_pfn(pfn, order);
buddy = page + (buddy_pfn - pfn);
--
2.22.0
