src/hotspot/share/runtime/safepoint.cpp

rev 47287 : Port 09.17.Thread_SMR_logging_update from JDK9 to JDK10
rev 47289 : eosterlund, stefank CR - refactor code into threadSMR.cpp and threadSMR.hpp
rev 47292 : stefank, coleenp CR - refactor most JavaThreadIterator usage to use JavaThreadIteratorWithHandle.

@@ -201,14 +201,13 @@
     // Consider using active_processor_count() ... but that call is expensive.
     int ncpus = os::processor_count() ;
     unsigned int iterations = 0;
 
     {
-      ThreadsListHandle tlh;
-      JavaThreadIterator jti(tlh.list());
+      JavaThreadIteratorWithHandle jtiwh;
 #ifdef ASSERT
-      for (JavaThread *cur = jti.first(); cur != NULL; cur = jti.next()) {
+      for (; JavaThread *cur = jtiwh.next(); ) {
         assert(cur->safepoint_state()->is_running(), "Illegal initial state");
         // Clear the visited flag to ensure that the critical counts are collected properly.
         cur->set_visited_for_critical_count(false);
       }
 #endif // ASSERT

@@ -217,11 +216,12 @@
         safepoint_limit_time = os::javaTimeNanos() + (jlong)SafepointTimeoutDelay * MICROUNITS;
 
       // Iterate through all threads until it have been determined how to stop them all at a safepoint
       int steps = 0 ;
       while(still_running > 0) {
-        for (JavaThread *cur = jti.first(); cur != NULL; cur = jti.next()) {
+        jtiwh.rewind();
+        for (; JavaThread *cur = jtiwh.next(); ) {
           assert(!cur->is_ConcurrentGC_thread(), "A concurrent GC thread is unexpectly being suspended");
           ThreadSafepointState *cur_state = cur->safepoint_state();
           if (cur_state->is_running()) {
             cur_state->examine_state_of_thread();
             if (!cur_state->is_running()) {

@@ -394,18 +394,14 @@
       wait_blocked_event.commit();
     }
   } // EventSafepointWaitBlocked
 
 #ifdef ASSERT
-  {
     // Make sure all the threads were visited.
-    ThreadsListHandle tlh;
-    JavaThreadIterator jti(tlh.list());
-    for (JavaThread *cur = jti.first(); cur != NULL; cur = jti.next()) {
+  for (JavaThreadIteratorWithHandle jtiwh; JavaThread *cur = jtiwh.next(); ) {
       assert(cur->was_visited_for_critical_count(), "missed a thread");
     }
-  }
 #endif // ASSERT
 
   // Update the count of active JNI critical regions
   GCLocker::set_jni_lock_count(_current_jni_active_count);
 

@@ -458,17 +454,16 @@
   if (PrintSafepointStatistics) {
     end_statistics(os::javaTimeNanos());
   }
 
   {
-    ThreadsListHandle tlh;
-    JavaThreadIterator jti(tlh.list());
+    JavaThreadIteratorWithHandle jtiwh;
 #ifdef ASSERT
     // A pending_exception cannot be installed during a safepoint.  The threads
     // may install an async exception after they come back from a safepoint into
     // pending_exception after they unblock.  But that should happen later.
-    for (JavaThread *cur = jti.first(); cur != NULL; cur = jti.next()) {
+    for (; JavaThread *cur = jtiwh.next(); ) {
       assert (!(cur->has_pending_exception() &&
                 cur->safepoint_state()->is_at_poll_safepoint()),
               "safepoint installed a pending exception");
     }
 #endif // ASSERT

@@ -493,11 +488,12 @@
       OrderAccess::fence();
 
       log_debug(safepoint)("Leaving safepoint region");
 
       // Start suspended threads
-      for (JavaThread *current = jti.first(); current != NULL; current = jti.next()) {
+      jtiwh.rewind();
+      for (; JavaThread *current = jtiwh.next(); ) {
         // A problem occurring on Solaris is when attempting to restart threads
         // the first #cpus - 1 go well, but then the VMThread is preempted when we get
         // to the next one (since it has been running the longest).  We then have
         // to wait for a cpu to become available before we can continue restarting
         // threads.

@@ -907,14 +903,11 @@
     }
 
     tty->print_cr("# SafepointSynchronize::begin: Threads which did not reach the safepoint:");
     ThreadSafepointState *cur_state;
     ResourceMark rm;
-    {
-      ThreadsListHandle tlh;
-      JavaThreadIterator jti(tlh.list());
-      for (JavaThread *cur_thread = jti.first(); cur_thread != NULL; cur_thread = jti.next()) {
+    for (JavaThreadIteratorWithHandle jtiwh; JavaThread *cur_thread = jtiwh.next(); ) {
         cur_state = cur_thread->safepoint_state();
 
         if (cur_thread->thread_state() != _thread_blocked &&
             ((reason == _spinning_timeout && cur_state->is_running()) ||
              (reason == _blocking_timeout && !cur_state->has_called_back()))) {

@@ -921,11 +914,10 @@
           tty->print("# ");
           cur_thread->print();
           tty->cr();
         }
       }
-    }
     tty->print_cr("# SafepointSynchronize::begin: (End of list)");
   }
 
   // To debug the long safepoint, specify both DieOnSafepointTimeout &
   // ShowMessageBoxOnError.

@@ -1421,13 +1413,11 @@
     tty->print_cr("not synchronized");
   } else if (_state == _synchronizing || _state == _synchronized) {
     tty->print_cr("State: %s", (_state == _synchronizing) ? "synchronizing" :
                   "synchronized");
 
-    ThreadsListHandle tlh;
-    JavaThreadIterator jti(tlh.list());
-    for (JavaThread *cur = jti.first(); cur != NULL; cur = jti.next()) {
+    for (JavaThreadIteratorWithHandle jtiwh; JavaThread *cur = jtiwh.next(); ) {
        cur->safepoint_state()->print();
     }
   }
 }