--- a/src/hotspot/share/gc/g1/g1CollectedHeap.cpp	Mon Mar 26 10:03:31 2018 +0200
+++ b/src/hotspot/share/gc/g1/g1CollectedHeap.cpp	Fri Mar 23 16:25:47 2018 +0100
@@ -2897,7 +2897,7 @@
     uint active_workers = AdaptiveSizePolicy::calc_active_workers(workers()->total_workers(),
                                                                   workers()->active_workers(),
                                                                   Threads::number_of_non_daemon_threads());
-    workers()->update_active_workers(active_workers);
+    active_workers = workers()->update_active_workers(active_workers);
     log_info(gc,task)("Using %u workers of %u for evacuation", active_workers, workers()->total_workers());
 
     TraceCollectorStats tcs(g1mm()->incremental_collection_counters());