Merge branch 'master' into for-next

Sync with Linus' tree to be able to apply fixes on top of newer things
in tree (efi-stub).

Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 13 insertions, 4 deletions

diff --git a/mm/compaction.c b/mm/compaction.c
index 05ccb4cc0bdb..805165bcd3dd 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -235,10 +235,9 @@ static bool suitable_migration_target(struct page *page)
 }
 
 /*
- * Isolate free pages onto a private freelist. Caller must hold zone->lock.
- * If @strict is true, will abort returning 0 on any invalid PFNs or non-free
- * pages inside of the pageblock (even though it may still end up isolating
- * some pages).
+ * Isolate free pages onto a private freelist. If @strict is true, will abort
+ * returning 0 on any invalid PFNs or non-free pages inside of the pageblock
+ * (even though it may still end up isolating some pages).
  */
 static unsigned long isolate_freepages_block(struct compact_control *cc,
 				unsigned long blockpfn,
@@ -677,6 +676,13 @@ static void isolate_freepages(struct zone *zone,
 					pfn -= pageblock_nr_pages) {
 		unsigned long isolated;
 
+		/*
+		 * This can iterate a massively long zone without finding any
+		 * suitable migration targets, so periodically check if we need
+		 * to schedule.
+		 */
+		cond_resched();
+
 		if (!pfn_valid(pfn))
 			continue;
 
@@ -1131,6 +1137,9 @@ void compact_pgdat(pg_data_t *pgdat, int order)
 		.sync = false,
 	};
 
+	if (!order)
+		return;
+
 	__compact_pgdat(pgdat, &cc);
 }