From: Miaohe Lin <linmiaohe@huawei.com>
Date: Fri, 29 Apr 2022 06:16:19 +0000 (-0700)
Subject: mm: compaction: make sure highest is above the min_pfn
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=ca2864e52d391f8df29da78261592502ffadd9d9;p=linux.git

mm: compaction: make sure highest is above the min_pfn

It's not guaranteed that highest will be above the min_pfn.  If highest is
below the min_pfn, migrate_pfn and free_pfn can meet prematurely and lead
to some useless work.  Make sure highest is above min_pfn to avoid making
a futile effort.

Link: https://lkml.kernel.org/r/20220418141253.24298-13-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Charan Teja Kalla <charante@codeaurora.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Pintu Kumar <pintu@codeaurora.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/compaction.c b/mm/compaction.c
index 609a76d7e0517..65970107b7895 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1532,7 +1532,7 @@ fast_isolate_freepages(struct compact_control *cc)
 			 * not found, be pessimistic for direct compaction
 			 * and use the min mark.
 			 */
-			if (highest) {
+			if (highest >= min_pfn) {
 				page = pfn_to_page(highest);
 				cc->free_pfn = highest;
 			} else {