mm: compaction: only force pageblock scan completion when skip hints are obeyed

fast_find_migrateblock relies on skip hints to avoid rescanning a recently
selected pageblock but compact_zone() only forces the pageblock scan
completion to set the skip hint if in direct compaction.  While this
prevents direct compaction repeatedly scanning a subset of blocks due to
fast_find_migrateblock(), it does not prevent proactive compaction, node
compaction and kcompactd encountering the same problem described in commit
cfccd2e ("mm, compaction: finish pageblocks on complete migration
failure").

Force the scan completion of a pageblock to set the skip hint if skip
hints are obeyed to prevent fast_find_migrateblock() repeatedly selecting
a subset of pageblocks.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Mel Gorman <[email protected]>
Suggested-by: Vlastimil Babka <[email protected]>
Tested-by: Raghavendra K T <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Cc: Chuyi Zhou <[email protected]>
Cc: Jiri Slaby <[email protected]>
Cc: Maxim Levitsky <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Pedro Falcato <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: gormanm

mm/compaction.c

@@ -2457,7 +2457,8 @@ compact_zone(struct compact_control *cc, struct capture_control *capc)
 			}
 			/*
 			 * If an ASYNC or SYNC_LIGHT fails to migrate a page
-			 * within the current order-aligned block, scan the
+			 * within the current order-aligned block and
+			 * fast_find_migrateblock may be used then scan the
 			 * remainder of the pageblock. This will mark the
 			 * pageblock "skip" to avoid rescanning in the near
 			 * future. This will isolate more pages than necessary
@@ -2466,7 +2467,7 @@ compact_zone(struct compact_control *cc, struct capture_control *capc)
 			 * recently partially scanned.
 			 */
 			if (!pageblock_aligned(cc->migrate_pfn) &&
-			    cc->direct_compaction && !cc->finish_pageblock &&
+			    !cc->ignore_skip_hint && !cc->finish_pageblock &&
 			    (cc->mode < MIGRATE_SYNC)) {
 				cc->finish_pageblock = true;