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From: Muchun Song <songmuchun@bytedance.com>
To: akpm@linux-foundation.org
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Muchun Song <songmuchun@bytedance.com>
Subject: [PATCH] mm/page_isolation: do not isolate the max order page
Date: Wed,  2 Dec 2020 20:21:14 +0800	[thread overview]
Message-ID: <20201202122114.75316-1-songmuchun@bytedance.com> (raw)

The max order page has no buddy page and never merge to other order.
So isolating and then freeing it is pointless.

Signed-off-by: Muchun Song <songmuchun@bytedance.com>
---
 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 a254e1f370a3..bddf788f45bf 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -88,7 +88,7 @@ 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);
-- 
2.11.0



             reply	other threads:[~2020-12-02 12:22 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-02 12:21 Muchun Song [this message]
2020-12-03  0:03 ` [PATCH] mm/page_isolation: do not isolate the max order page Vlastimil Babka
2020-12-03  2:43   ` [External] " Muchun Song
2020-12-03 15:49     ` Vlastimil Babka
2020-12-03 16:26   ` David Hildenbrand
2020-12-03 17:15     ` Vlastimil Babka
2020-12-03 17:48       ` David Hildenbrand
2020-12-03 19:24         ` David Hildenbrand
2020-12-03 16:27 ` David Hildenbrand

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