# HG changeset patch
# User dtitov
# Date 1570552750 25200
# Node ID 94dd00d2da29bde7d4a8cd29bee225a3f84b3dfb
# Parent  726a3945e93425d99f4b5419a51980db0d1c8807
8231666: ThreadIdTable::grow() invokes invalid thread transition
Reviewed-by: dholmes, rehn

diff -r 726a3945e934 -r 94dd00d2da29 src/hotspot/share/runtime/serviceThread.cpp
--- a/src/hotspot/share/runtime/serviceThread.cpp	Tue Oct 08 09:13:08 2019 -0700
+++ b/src/hotspot/share/runtime/serviceThread.cpp	Tue Oct 08 09:39:10 2019 -0700
@@ -43,6 +43,7 @@
 #include "services/diagnosticFramework.hpp"
 #include "services/gcNotifier.hpp"
 #include "services/lowMemoryDetector.hpp"
+#include "services/threadIdTable.hpp"
 
 ServiceThread* ServiceThread::_instance = NULL;
 
@@ -101,6 +102,7 @@
     bool stringtable_work = false;
     bool symboltable_work = false;
     bool resolved_method_table_work = false;
+    bool thread_id_table_work = false;
     bool protection_domain_table_work = false;
     bool oopstorage_work = false;
     JvmtiDeferredEvent jvmti_event;
@@ -127,6 +129,7 @@
               (stringtable_work = StringTable::has_work()) |
               (symboltable_work = SymbolTable::has_work()) |
               (resolved_method_table_work = ResolvedMethodTable::has_work()) |
+              (thread_id_table_work = ThreadIdTable::has_work()) |
               (protection_domain_table_work = SystemDictionary::pd_cache_table()->has_work()) |
               (oopstorage_work = OopStorage::has_cleanup_work_and_reset())
              ) == 0) {
@@ -169,6 +172,10 @@
       ResolvedMethodTable::do_concurrent_work(jt);
     }
 
+    if (thread_id_table_work) {
+      ThreadIdTable::do_concurrent_work(jt);
+    }
+
     if (protection_domain_table_work) {
       SystemDictionary::pd_cache_table()->unlink();
     }
diff -r 726a3945e934 -r 94dd00d2da29 src/hotspot/share/services/threadIdTable.cpp
--- a/src/hotspot/share/services/threadIdTable.cpp	Tue Oct 08 09:13:08 2019 -0700
+++ b/src/hotspot/share/services/threadIdTable.cpp	Tue Oct 08 09:39:10 2019 -0700
@@ -46,6 +46,7 @@
 static volatile size_t _items_count = 0;
 
 volatile bool ThreadIdTable::_is_initialized = false;
+volatile bool ThreadIdTable::_has_work = false;
 
 class ThreadIdTableEntry : public CHeapObj<mtInternal> {
 private:
@@ -141,6 +142,26 @@
   return (size_t)1 << _local_table->get_size_log2(Thread::current());
 }
 
+void ThreadIdTable::check_concurrent_work() {
+  if (_has_work) {
+    return;
+  }
+
+  double load_factor = get_load_factor();
+  // Resize if we have more items than preferred load factor
+  if ( load_factor > PREF_AVG_LIST_LEN && !_local_table->is_max_size_reached()) {
+    log_debug(thread, table)("Concurrent work triggered, load factor: %g",
+                             load_factor);
+    trigger_concurrent_work();
+  }
+}
+
+void ThreadIdTable::trigger_concurrent_work() {
+  MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
+  _has_work = true;
+  Service_lock->notify_all();
+}
+
 void ThreadIdTable::grow(JavaThread* jt) {
   ThreadIdTableHash::GrowTask gt(_local_table);
   if (!gt.prepare(jt)) {
@@ -192,13 +213,13 @@
   }
 };
 
-void ThreadIdTable::grow_if_required() {
-  assert(Thread::current()->is_Java_thread(),"Must be Java thread");
+void ThreadIdTable::do_concurrent_work(JavaThread* jt) {
   assert(_is_initialized, "Thread table is not initialized");
+  _has_work = false;
   double load_factor = get_load_factor();
   log_debug(thread, table)("Concurrent work, load factor: %g", load_factor);
   if (load_factor > PREF_AVG_LIST_LEN && !_local_table->is_max_size_reached()) {
-    grow(JavaThread::current());
+    grow(jt);
   }
 }
 
@@ -215,7 +236,7 @@
     // The hash table takes ownership of the ThreadTableEntry,
     // even if it's not inserted.
     if (_local_table->insert(thread, lookup, entry)) {
-      grow_if_required();
+      check_concurrent_work();
       return java_thread;
     }
   }
diff -r 726a3945e934 -r 94dd00d2da29 src/hotspot/share/services/threadIdTable.hpp
--- a/src/hotspot/share/services/threadIdTable.hpp	Tue Oct 08 09:13:08 2019 -0700
+++ b/src/hotspot/share/services/threadIdTable.hpp	Tue Oct 08 09:39:10 2019 -0700
@@ -36,6 +36,7 @@
   friend class ThreadIdTableConfig;
 
   static volatile bool _is_initialized;
+  static volatile bool _has_work;
 
 public:
   // Initialization
@@ -47,12 +48,17 @@
   static JavaThread* add_thread(jlong tid, JavaThread* thread);
   static bool remove_thread(jlong tid);
 
+  // Growing
+  static bool has_work() { return _has_work; }
+  static void do_concurrent_work(JavaThread* jt);
+
 private:
   static void create_table(size_t size);
 
   static size_t table_size();
   static double get_load_factor();
-  static void grow_if_required();
+  static void check_concurrent_work();
+  static void trigger_concurrent_work();
   static void grow(JavaThread* jt);
 
   static void item_added();
diff -r 726a3945e934 -r 94dd00d2da29 test/jdk/javax/management/mxbean/ThreadStartTest.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/javax/management/mxbean/ThreadStartTest.java	Tue Oct 08 09:39:10 2019 -0700
@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2019, 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.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8231666
+ * @summary Test checks that new threads could be successfully started when the thread
+ * table introduced in 8185005 is growing. The test enables the thread table by calling
+ * ThreadMXBean.getThreadInfo() and then creates a number of threads to force the thread
+ * table to grow.
+ *
+ * @run main ThreadStartTest
+ */
+
+import java.lang.management.ManagementFactory;
+import java.lang.management.ThreadMXBean;
+
+public class ThreadStartTest {
+    public static void main(String[] args) {
+
+        ThreadMXBean mbean = ManagementFactory.getThreadMXBean();
+        // Enable thread table
+        mbean.getThreadInfo(Thread.currentThread().getId());
+
+        // Create a large number of threads to make the thread table grow
+        for (int i = 0; i < 1000; i++) {
+            Thread t = new Thread(() -> {
+                try {
+                    Thread.sleep(1000);
+                } catch (InterruptedException ex) {
+                }
+            });
+            t.start();
+        }
+    }
+}