--- old/src/hotspot/share/runtime/threadSMR.cpp	2019-07-24 07:52:54.000000000 -0700
+++ new/src/hotspot/share/runtime/threadSMR.cpp	2019-07-24 07:52:54.000000000 -0700
@@ -26,10 +26,12 @@
 #include "logging/logStream.hpp"
 #include "memory/allocation.inline.hpp"
 #include "runtime/jniHandles.inline.hpp"
+#include "runtime/sharedRuntime.hpp"
 #include "runtime/thread.inline.hpp"
 #include "runtime/threadSMR.inline.hpp"
 #include "runtime/vmOperations.hpp"
 #include "services/threadService.hpp"
+#include "services/threadTable.hpp"
 #include "utilities/copy.hpp"
 #include "utilities/globalDefinitions.hpp"
 #include "utilities/ostream.hpp"
@@ -129,7 +131,6 @@
 // Impl note: See _to_delete_list_cnt note.
 uint                  ThreadsSMRSupport::_to_delete_list_max = 0;
 
-
 // 'inline' functions first so the definitions are before first use:
 
 inline void ThreadsSMRSupport::add_deleted_thread_times(uint add_value) {
@@ -608,20 +609,28 @@
 }
 
 JavaThread* ThreadsList::find_JavaThread_from_java_tid(jlong java_tid) const {
-  for (uint i = 0; i < length(); i++) {
-    JavaThread* thread = thread_at(i);
-    oop tobj = thread->threadObj();
-    // Ignore the thread if it hasn't run yet, has exited
-    // or is starting to exit.
-    if (tobj != NULL && !thread->is_exiting() &&
-        java_tid == java_lang_Thread::thread_id(tobj)) {
-      // found a match
-      return thread;
+  ThreadTable::lazy_initialize(this);
+  JavaThread* java_thread = ThreadTable::find_thread_by_tid(java_tid);
+  if (java_thread == NULL) {
+    // If the thread is not found in the table find it
+    // with a linear search and add to the table.
+    for (uint i = 0; i < length(); i++) {
+      JavaThread* thread = thread_at(i);
+      oop tobj = thread->threadObj();
+      // Ignore the thread if it hasn't run yet, has exited
+      // or is starting to exit.
+      if (tobj != NULL && !thread->is_exiting() &&
+          java_tid == java_lang_Thread::thread_id(tobj)) {
+        ThreadTable::add_thread(java_tid, thread);
+        return thread;
+      }
     }
+  } else if (java_thread != NULL && !java_thread->is_exiting()) {
+      return java_thread;
   }
   return NULL;
 }
-
+    
 void ThreadsList::inc_nested_handle_cnt() {
   // The increment needs to be MO_SEQ_CST so that the reference counter
   // update is seen before the subsequent hazard ptr update.
@@ -742,6 +751,10 @@
 
   ThreadsList *old_list = xchg_java_thread_list(new_list);
   free_list(old_list);
+  if (ThreadTable::is_initialized()) {
+    jlong tid = SharedRuntime::get_java_tid(thread);
+    ThreadTable::add_thread(tid, thread);
+  }
 }
 
 // set_delete_notify() and clear_delete_notify() are called
@@ -909,6 +922,10 @@
 }
 
 void ThreadsSMRSupport::remove_thread(JavaThread *thread) {
+  if (ThreadTable::is_initialized()) {
+    jlong tid = SharedRuntime::get_java_tid(thread);
+    ThreadTable::remove_thread(tid);
+  }
   ThreadsList *new_list = ThreadsList::remove_thread(ThreadsSMRSupport::get_java_thread_list(), thread);
   if (EnableThreadSMRStatistics) {
     ThreadsSMRSupport::inc_java_thread_list_alloc_cnt();