8314243: Make VM_Exit::wait_for_threads_in_native_to_block wait for u…

…ser threads time configurable

src/hotspot/share/runtime/globals.hpp

@@ -831,6 +831,11 @@ const int ObjectAlignmentInBytes = 8;
           "JVM aborts, producing an error log and core/mini dump, on the "  \
           "first occurrence of an out-of-memory error thrown from JVM")     \
                                                                             \
+  product(intx, WaitUserThreadAtExitTimeout, 300,                           \
+          "Maximum delay in milliseconds at exit waiting for user threads " \
+          "in native")                                                      \
+          range(0, max_intx)                                                \
+                                                                            \
   /* tracing */                                                             \
                                                                             \
   develop(bool, StressRewriter, false,                                      \

src/hotspot/share/runtime/vmOperations.cpp

@@ -391,10 +391,10 @@ int VM_Exit::wait_for_threads_in_native_to_block() {
   // don't have to wait for user threads to be quiescent, but it's always
   // better to terminate VM when current thread is the only active thread, so
   // wait for user threads too. Numbers are in 10 milliseconds.
-  int max_wait_user_thread = 30;                  // at least 300 milliseconds
-  int max_wait_compiler_thread = 1000;            // at least 10 seconds
-
-  int max_wait = max_wait_compiler_thread;
+  int wait_time_per_attempt = 10;                 // in milliseconds
+  int max_wait_attempts_user_thread =
+                  WaitUserThreadAtExitTimeout / wait_time_per_attempt;
+  int max_wait_attempts_compiler_thread = 1000; // at least 10 seconds
 
   int attempts = 0;
   JavaThreadIteratorWithHandle jtiwh;
@@ -427,16 +427,17 @@ int VM_Exit::wait_for_threads_in_native_to_block() {
 
     if (num_active == 0) {
        return 0;
-    } else if (attempts > max_wait) {
+    } else if (attempts >= max_wait_attempts_compiler_thread) {
        return num_active;
-    } else if (num_active_compiler_thread == 0 && attempts > max_wait_user_thread) {
+    } else if (num_active_compiler_thread == 0 &&
+               attempts >= max_wait_attempts_user_thread) {
        return num_active;
     }
 
     attempts++;
 
     MonitorLocker ml(&timer, Mutex::_no_safepoint_check_flag);
-    ml.wait(10);
+    ml.wait(wait_time_per_attempt);
   }
 }