src/share/vm/gc/cms/concurrentMarkSweepThread.cpp

rev 10297 : [mq]: webrev.01
rev 10298 : [mq]: webrev.02

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2016, 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.

@@ -40,11 +40,10 @@
 
 // ======= Concurrent Mark Sweep Thread ========
 
 ConcurrentMarkSweepThread* ConcurrentMarkSweepThread::_cmst = NULL;
 CMSCollector* ConcurrentMarkSweepThread::_collector         = NULL;
-bool ConcurrentMarkSweepThread::_should_terminate           = false;
 int  ConcurrentMarkSweepThread::_CMS_flag                   = CMS_nil;
 
 volatile jint ConcurrentMarkSweepThread::_pending_yields    = 0;
 
 SurrogateLockerThread* ConcurrentMarkSweepThread::_slt      = NULL;

@@ -60,11 +59,10 @@
   assert(_collector == NULL, "Collector already set");
   _collector = collector;
 
   set_name("CMS Main Thread");
 
-  if (os::create_thread(this, os::cgc_thread)) {
     // An old comment here said: "Priority should be just less
     // than that of VMThread".  Since the VMThread runs at
     // NearMaxPriority, the old comment was inaccurate, but
     // changing the default priority to NearMaxPriority-1
     // could change current behavior, so the default of

@@ -72,46 +70,27 @@
     //
     // Note that there's a possibility of the VMThread
     // starving if UseCriticalCMSThreadPriority is on.
     // That won't happen on Solaris for various reasons,
     // but may well happen on non-Solaris platforms.
-    int native_prio;
-    if (UseCriticalCMSThreadPriority) {
-      native_prio = os::java_to_os_priority[CriticalPriority];
-    } else {
-      native_prio = os::java_to_os_priority[NearMaxPriority];
-    }
-    os::set_native_priority(this, native_prio);
+  create_and_start(UseCriticalCMSThreadPriority ? CriticalPriority : NearMaxPriority);
 
-    if (!DisableStartThread) {
-      os::start_thread(this);
-    }
-  }
   _sltMonitor = SLT_lock;
 }
 
-void ConcurrentMarkSweepThread::run() {
+void ConcurrentMarkSweepThread::run_service() {
   assert(this == cmst(), "just checking");
 
-  initialize_in_thread();
-  // From this time Thread::current() should be working.
-  assert(this == Thread::current(), "just checking");
   if (BindCMSThreadToCPU && !os::bind_to_processor(CPUForCMSThread)) {
     warning("Couldn't bind CMS thread to processor " UINTX_FORMAT, CPUForCMSThread);
   }
-  // Wait until Universe::is_fully_initialized()
+
   {
-    CMSLoopCountWarn loopX("CMS::run", "waiting for "
-                           "Universe::is_fully_initialized()", 2);
     MutexLockerEx x(CGC_lock, true);
     set_CMS_flag(CMS_cms_wants_token);
-    // Wait until Universe is initialized and all initialization is completed.
-    while (!is_init_completed() && !Universe::is_fully_initialized() &&
-           !_should_terminate) {
-      CGC_lock->wait(true, 200);
-      loopX.tick();
-    }
+    assert(is_init_completed() && Universe::is_fully_initialized(), "ConcurrentGCThread::run() should have waited for this.");
+
     // Wait until the surrogate locker thread that will do
     // pending list locking on our behalf has been created.
     // We cannot start the SLT thread ourselves since we need
     // to be a JavaThread to do so.
     CMSLoopCountWarn loopY("CMS::run", "waiting for SLT installation", 2);

@@ -128,24 +107,16 @@
     GCIdMark gc_id_mark;
     GCCause::Cause cause = _collector->_full_gc_requested ?
       _collector->_full_gc_cause : GCCause::_cms_concurrent_mark;
     _collector->collect_in_background(cause);
   }
-  assert(_should_terminate, "just checking");
+
   // Check that the state of any protocol for synchronization
   // between background (CMS) and foreground collector is "clean"
   // (i.e. will not potentially block the foreground collector,
   // requiring action by us).
   verify_ok_to_terminate();
-  // Signal that it is terminated
-  {
-    MutexLockerEx mu(Terminator_lock,
-                     Mutex::_no_safepoint_check_flag);
-    assert(_cmst == this, "Weird!");
-    _cmst = NULL;
-    Terminator_lock->notify();
-  }
 }
 
 #ifndef PRODUCT
 void ConcurrentMarkSweepThread::verify_ok_to_terminate() const {
   assert(!(CGC_lock->owned_by_self() || cms_thread_has_cms_token() ||

@@ -155,43 +126,33 @@
 }
 #endif
 
 // create and start a new ConcurrentMarkSweep Thread for given CMS generation
 ConcurrentMarkSweepThread* ConcurrentMarkSweepThread::start(CMSCollector* collector) {
-  if (!_should_terminate) {
-    assert(cmst() == NULL, "start() called twice?");
+  guarantee(_cmst == NULL, "start() called twice!");
     ConcurrentMarkSweepThread* th = new ConcurrentMarkSweepThread(collector);
-    assert(cmst() == th, "Where did the just-created CMS thread go?");
+  assert(_cmst == th, "Where did the just-created CMS thread go?");
     return th;
-  }
-  return NULL;
 }
 
-void ConcurrentMarkSweepThread::stop() {
-  // it is ok to take late safepoints here, if needed
-  {
-    MutexLockerEx x(Terminator_lock);
-    _should_terminate = true;
-  }
-  { // Now post a notify on CGC_lock so as to nudge
+void ConcurrentMarkSweepThread::stop_all() {
+  assert(_cmst != NULL, "stop_all should be called after initialization");
+  _cmst->stop();
+}
+
+void ConcurrentMarkSweepThread::stop_service() {
+  // Now post a notify on CGC_lock so as to nudge
     // CMS thread(s) that might be slumbering in
     // sleepBeforeNextCycle.
     MutexLockerEx x(CGC_lock, Mutex::_no_safepoint_check_flag);
     CGC_lock->notify_all();
-  }
-  { // Now wait until (all) CMS thread(s) have exited
-    MutexLockerEx x(Terminator_lock);
-    while(cmst() != NULL) {
-      Terminator_lock->wait();
-    }
-  }
 }
 
 void ConcurrentMarkSweepThread::threads_do(ThreadClosure* tc) {
   assert(tc != NULL, "Null ThreadClosure");
-  if (_cmst != NULL) {
-    tc->do_thread(_cmst);
+  if (cmst() != NULL) {
+    tc->do_thread(cmst());
   }
   assert(Universe::is_fully_initialized(),
          "Called too early, make sure heap is fully initialized");
   if (_collector != NULL) {
     AbstractWorkGang* gang = _collector->conc_workers();

@@ -200,12 +161,12 @@
     }
   }
 }
 
 void ConcurrentMarkSweepThread::print_all_on(outputStream* st) {
-  if (_cmst != NULL) {
-    _cmst->print_on(st);
+  if (cmst() != NULL) {
+    cmst()->print_on(st);
     st->cr();
   }
   if (_collector != NULL) {
     AbstractWorkGang* gang = _collector->conc_workers();
     if (gang != NULL) {