--- old/src/hotspot/cpu/zero/globals_zero.hpp	2019-10-17 17:28:44.000000000 -0400
+++ new/src/hotspot/cpu/zero/globals_zero.hpp	2019-10-17 17:28:43.000000000 -0400
@@ -77,6 +77,9 @@
 define_pd_global(bool, CompactStrings, false);
 
 define_pd_global(bool, ThreadLocalHandshakes, true);
+// No ObjectMonitor C2 fast_lock() or fast_unlock() so no need to
+// use a handshake for safety.
+define_pd_global(bool, HandshakeAfterDeflateIdleMonitors, false);
 
 #define ARCH_FLAGS(develop, \
                    product, \