mm: compaction: clean up comment about suitable migration target recheck

checked_pageblock is already removed and suitable_migration_target is not
rechecked under the zone lock since commit f8224aa5 ("mm, compaction:
do not recheck suitable_migration_target under lock").  Correct the
comment accordingly.

Link: https://lkml.kernel.org/r/20220418141253.24298-6-linmiaohe@huawei.comSigned-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>

mm/compaction.c

@@ -599,13 +599,7 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
 		if (!PageBuddy(page))
 			goto isolate_fail;
 
-		/*
-		 * If we already hold the lock, we can skip some rechecking.
-		 * Note that if we hold the lock now, checked_pageblock was
-		 * already set in some previous iteration (or strict is true),
-		 * so it is correct to skip the suitable migration target
-		 * recheck as well.
-		 */
+		/* If we already hold the lock, we can skip some rechecking. */
 		if (!locked) {
 			locked = compact_lock_irqsave(&cc->zone->lock,
 								&flags, cc);