# HG changeset patch
# User dlong
# Date 1539834959 25200
#      Wed Oct 17 20:55:59 2018 -0700
# Node ID aee8454df07bcdb62c660bbc579364d991fad02a
# Parent  367b2cd49ec5efad2f89346d3c0d1ddcc115d70c
[mq]: 8021335

diff --git a/src/hotspot/share/runtime/thread.cpp b/src/hotspot/share/runtime/thread.cpp
--- a/src/hotspot/share/runtime/thread.cpp
+++ b/src/hotspot/share/runtime/thread.cpp
@@ -1819,6 +1819,9 @@
   thread->clear_pending_exception();
 }
 
+static bool is_daemon(oop threadObj) {
+  return (threadObj != NULL && java_lang_Thread::is_daemon(threadObj));
+}
 
 // For any new cleanup additions, please check to see if they need to be applied to
 // cleanup_failed_attach_current_thread as well.
@@ -1910,7 +1913,6 @@
         MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
         if (!is_external_suspend()) {
           set_terminated(_thread_exiting);
-          ThreadService::current_thread_exiting(this);
           break;
         }
         // Implied else:
@@ -1929,7 +1931,11 @@
       // exiting.
     }
     // no more external suspends are allowed at this point
+    { MutexLocker mu(Threads_lock);
+      ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
+    }
   } else {
+    assert(!is_terminated() && !is_exiting(), "must not be exiting");
     // before_exit() has already posted JVMTI THREAD_END events
   }
 
@@ -4332,7 +4338,7 @@
 
 void Threads::add(JavaThread* p, bool force_daemon) {
   // The threads lock must be owned at this point
-  assert_locked_or_safepoint(Threads_lock);
+  assert(Threads_lock->owned_by_self(), "must have threads lock");
 
   BarrierSet::barrier_set()->on_thread_attach(p);
 
@@ -4348,7 +4354,7 @@
   bool daemon = true;
   // Bootstrapping problem: threadObj can be null for initial
   // JavaThread (or for threads attached via JNI)
-  if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
+  if ((!force_daemon) && !is_daemon((threadObj))) {
     _number_of_non_daemon_threads++;
     daemon = false;
   }
@@ -4393,7 +4399,7 @@
     _number_of_threads--;
     oop threadObj = p->threadObj();
     bool daemon = true;
-    if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
+    if (!is_daemon(threadObj)) {
       _number_of_non_daemon_threads--;
       daemon = false;
 
diff --git a/src/hotspot/share/services/threadService.cpp b/src/hotspot/share/services/threadService.cpp
--- a/src/hotspot/share/services/threadService.cpp
+++ b/src/hotspot/share/services/threadService.cpp
@@ -57,8 +57,6 @@
 PerfVariable* ThreadService::_live_threads_count = NULL;
 PerfVariable* ThreadService::_peak_threads_count = NULL;
 PerfVariable* ThreadService::_daemon_threads_count = NULL;
-volatile int ThreadService::_exiting_threads_count = 0;
-volatile int ThreadService::_exiting_daemon_threads_count = 0;
 
 ThreadDumpResult* ThreadService::_threaddump_list = NULL;
 
@@ -101,10 +99,16 @@
   _peak_threads_count->set_value(get_live_thread_count());
 }
 
+static bool is_hidden_thread(JavaThread *thread) {
+  // hide VM internal or JVMTI agent threads
+  return thread->is_hidden_from_external_view() || thread->is_jvmti_agent_thread();
+}
+
 void ThreadService::add_thread(JavaThread* thread, bool daemon) {
-  // Do not count VM internal or JVMTI agent threads
-  if (thread->is_hidden_from_external_view() ||
-      thread->is_jvmti_agent_thread()) {
+  assert(Threads_lock->owned_by_self(), "must have threads lock");
+
+  // Do not count hidden threads
+  if (is_hidden_thread(thread)) {
     return;
   }
 
@@ -120,31 +124,44 @@
   }
 }
 
+void ThreadService::decrement_thread_counts(JavaThread* jt, bool daemon) {
+  assert(Threads_lock->owned_by_self(), "must have threads lock");
+
+  _live_threads_count->dec(1);
+
+  if (daemon) {
+    _daemon_threads_count->dec(1);
+  }
+}
+
 void ThreadService::remove_thread(JavaThread* thread, bool daemon) {
-  Atomic::dec(&_exiting_threads_count);
-  if (daemon) {
-    Atomic::dec(&_exiting_daemon_threads_count);
-  }
+  assert(Threads_lock->owned_by_self(), "must have threads lock");
 
-  if (thread->is_hidden_from_external_view() ||
-      thread->is_jvmti_agent_thread()) {
+  // Do not count hidden threads
+  if (is_hidden_thread(thread)) {
     return;
   }
 
-  _live_threads_count->set_value(_live_threads_count->get_value() - 1);
-  if (daemon) {
-    _daemon_threads_count->set_value(_daemon_threads_count->get_value() - 1);
+  assert(!thread->is_terminated(), "must not be terminated");
+  if (!thread->is_exiting()) {
+    // JavaThread::exit() skipped calling current_thread_exiting()
+    decrement_thread_counts(thread, daemon);
   }
+
 }
 
-void ThreadService::current_thread_exiting(JavaThread* jt) {
+void ThreadService::current_thread_exiting(JavaThread* jt, bool daemon) {
+  assert(Threads_lock->owned_by_self(), "must have threads lock");
+
+  // Do not count hidden threads
+  if (is_hidden_thread(jt)) {
+    return;
+  }
+
   assert(jt == JavaThread::current(), "Called by current thread");
-  Atomic::inc(&_exiting_threads_count);
+  assert(!jt->is_terminated() && jt->is_exiting(), "must be exiting");
 
-  oop threadObj = jt->threadObj();
-  if (threadObj != NULL && java_lang_Thread::is_daemon(threadObj)) {
-    Atomic::inc(&_exiting_daemon_threads_count);
-  }
+  decrement_thread_counts(jt, daemon);
 }
 
 // FIXME: JVMTI should call this function
diff --git a/src/hotspot/share/services/threadService.hpp b/src/hotspot/share/services/threadService.hpp
--- a/src/hotspot/share/services/threadService.hpp
+++ b/src/hotspot/share/services/threadService.hpp
@@ -58,11 +58,6 @@
   static PerfVariable* _peak_threads_count;
   static PerfVariable* _daemon_threads_count;
 
-  // These 2 counters are atomically incremented once the thread is exiting.
-  // They will be atomically decremented when ThreadService::remove_thread is called.
-  static volatile int  _exiting_threads_count;
-  static volatile int  _exiting_daemon_threads_count;
-
   static bool          _thread_monitoring_contention_enabled;
   static bool          _thread_cpu_time_enabled;
   static bool          _thread_allocated_memory_enabled;
@@ -72,11 +67,13 @@
   // requested by multiple threads concurrently.
   static ThreadDumpResult* _threaddump_list;
 
+  static void decrement_thread_counts(JavaThread* jt, bool daemon);
+
 public:
   static void init();
   static void add_thread(JavaThread* thread, bool daemon);
   static void remove_thread(JavaThread* thread, bool daemon);
-  static void current_thread_exiting(JavaThread* jt);
+  static void current_thread_exiting(JavaThread* jt, bool daemon);
 
   static bool set_thread_monitoring_contention(bool flag);
   static bool is_thread_monitoring_contention() { return _thread_monitoring_contention_enabled; }
@@ -89,11 +86,8 @@
 
   static jlong get_total_thread_count()       { return _total_threads_count->get_value(); }
   static jlong get_peak_thread_count()        { return _peak_threads_count->get_value(); }
-  static jlong get_live_thread_count()        { return _live_threads_count->get_value() - _exiting_threads_count; }
-  static jlong get_daemon_thread_count()      { return _daemon_threads_count->get_value() - _exiting_daemon_threads_count; }
-
-  static int   exiting_threads_count()        { return _exiting_threads_count; }
-  static int   exiting_daemon_threads_count() { return _exiting_daemon_threads_count; }
+  static jlong get_live_thread_count()        { return _live_threads_count->get_value(); }
+  static jlong get_daemon_thread_count()      { return _daemon_threads_count->get_value(); }
 
   // Support for thread dump
   static void   add_thread_dump(ThreadDumpResult* dump);