src/hotspot/share/runtime/threadSMR.cpp

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 2017, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2017, 2020, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.

@@ -948,18 +948,34 @@
 
 // Safely delete a JavaThread when it is no longer in use by a
 // ThreadsListHandle.
 //
 void ThreadsSMRSupport::smr_delete(JavaThread *thread) {
-  assert(!Threads_lock->owned_by_self(), "sanity");
-
-  bool has_logged_once = false;
   elapsedTimer timer;
   if (EnableThreadSMRStatistics) {
     timer.start();
   }
 
+  wait_until_not_protected(thread);
+
+  delete thread;
+  if (EnableThreadSMRStatistics) {
+    timer.stop();
+    uint millis = (uint)timer.milliseconds();
+    ThreadsSMRSupport::inc_deleted_thread_cnt();
+    ThreadsSMRSupport::add_deleted_thread_times(millis);
+    ThreadsSMRSupport::update_deleted_thread_time_max(millis);
+  }
+
+  log_debug(thread, smr)("tid=" UINTX_FORMAT ": ThreadsSMRSupport::smr_delete: thread=" INTPTR_FORMAT " is deleted.", os::current_thread_id(), p2i(thread));
+}
+
+void ThreadsSMRSupport::wait_until_not_protected(JavaThread *thread) {
+  assert(!Threads_lock->owned_by_self(), "sanity");
+
+  bool has_logged_once = false;
+
   while (true) {
     {
       // Will not make a safepoint check because this JavaThread
       // is not on the current ThreadsList.
       MutexLocker ml(Threads_lock);

@@ -977,18 +993,18 @@
         ThreadsSMRSupport::delete_lock()->unlock();
         break;
       }
       if (!has_logged_once) {
         has_logged_once = true;
-        log_debug(thread, smr)("tid=" UINTX_FORMAT ": ThreadsSMRSupport::smr_delete: thread=" INTPTR_FORMAT " is not deleted.", os::current_thread_id(), p2i(thread));
+        log_debug(thread, smr)("tid=" UINTX_FORMAT ": ThreadsSMRSupport::wait_until_not_protected: thread=" INTPTR_FORMAT " is not deleted.", os::current_thread_id(), p2i(thread));
         if (log_is_enabled(Debug, os, thread)) {
           ScanHazardPtrPrintMatchingThreadsClosure scan_cl(thread);
           threads_do(&scan_cl);
           ThreadsList* current = _to_delete_list;
           while (current != NULL) {
             if (current->_nested_handle_cnt != 0 && current->includes(thread)) {
-              log_debug(thread, smr)("tid=" UINTX_FORMAT ": ThreadsSMRSupport::smr_delete: found nested hazard pointer to thread=" INTPTR_FORMAT, os::current_thread_id(), p2i(thread));
+              log_debug(thread, smr)("tid=" UINTX_FORMAT ": ThreadsSMRSupport::wait_until_not_protected: found nested hazard pointer to thread=" INTPTR_FORMAT, os::current_thread_id(), p2i(thread));
             }
             current = current->next_list();
           }
         }
       }

@@ -1010,21 +1026,10 @@
 
     ThreadsSMRSupport::clear_delete_notify();
     ThreadsSMRSupport::delete_lock()->unlock();
     // Retry the whole scenario.
   }
-
-  delete thread;
-  if (EnableThreadSMRStatistics) {
-    timer.stop();
-    uint millis = (uint)timer.milliseconds();
-    ThreadsSMRSupport::inc_deleted_thread_cnt();
-    ThreadsSMRSupport::add_deleted_thread_times(millis);
-    ThreadsSMRSupport::update_deleted_thread_time_max(millis);
-  }
-
-  log_debug(thread, smr)("tid=" UINTX_FORMAT ": ThreadsSMRSupport::smr_delete: thread=" INTPTR_FORMAT " is deleted.", os::current_thread_id(), p2i(thread));
 }
 
 // Apply the closure to all threads in the system, with a snapshot of
 // all JavaThreads provided by the list parameter.
 void ThreadsSMRSupport::threads_do(ThreadClosure *tc, ThreadsList *list) {