8187443: Forest Consolidation: Move files to unified layout

Reviewed-by: darcy, ihse

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

@@ -0,0 +1,314 @@
+/*
+ * 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.
+ *
+ * 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.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "classfile/systemDictionary.hpp"
+#include "gc/cms/concurrentMarkSweepGeneration.inline.hpp"
+#include "gc/cms/concurrentMarkSweepThread.hpp"
+#include "gc/shared/gcId.hpp"
+#include "gc/shared/genCollectedHeap.hpp"
+#include "oops/oop.inline.hpp"
+#include "runtime/init.hpp"
+#include "runtime/interfaceSupport.hpp"
+#include "runtime/java.hpp"
+#include "runtime/javaCalls.hpp"
+#include "runtime/mutexLocker.hpp"
+#include "runtime/os.hpp"
+#include "runtime/vmThread.hpp"
+
+// ======= Concurrent Mark Sweep Thread ========
+
+ConcurrentMarkSweepThread* ConcurrentMarkSweepThread::_cmst = NULL;
+CMSCollector* ConcurrentMarkSweepThread::_collector         = NULL;
+int  ConcurrentMarkSweepThread::_CMS_flag                   = CMS_nil;
+
+volatile jint ConcurrentMarkSweepThread::_pending_yields    = 0;
+
+ConcurrentMarkSweepThread::ConcurrentMarkSweepThread(CMSCollector* collector)
+  : ConcurrentGCThread() {
+  assert(UseConcMarkSweepGC,  "UseConcMarkSweepGC should be set");
+  assert(_cmst == NULL, "CMS thread already created");
+  _cmst = this;
+  assert(_collector == NULL, "Collector already set");
+  _collector = collector;
+
+  set_name("CMS Main 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
+  // NearMaxPriority stays in place.
+  //
+  // 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.
+  create_and_start(UseCriticalCMSThreadPriority ? CriticalPriority : NearMaxPriority);
+}
+
+void ConcurrentMarkSweepThread::run_service() {
+  assert(this == cmst(), "just checking");
+
+  if (BindCMSThreadToCPU && !os::bind_to_processor(CPUForCMSThread)) {
+    log_warning(gc)("Couldn't bind CMS thread to processor " UINTX_FORMAT, CPUForCMSThread);
+  }
+
+  while (!should_terminate()) {
+    sleepBeforeNextCycle();
+    if (should_terminate()) break;
+    GCIdMark gc_id_mark;
+    GCCause::Cause cause = _collector->_full_gc_requested ?
+      _collector->_full_gc_cause : GCCause::_cms_concurrent_mark;
+    _collector->collect_in_background(cause);
+  }
+
+  // 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();
+}
+
+#ifndef PRODUCT
+void ConcurrentMarkSweepThread::verify_ok_to_terminate() const {
+  assert(!(CGC_lock->owned_by_self() || cms_thread_has_cms_token() ||
+           cms_thread_wants_cms_token()),
+         "Must renounce all worldly possessions and desires for nirvana");
+  _collector->verify_ok_to_terminate();
+}
+#endif
+
+// create and start a new ConcurrentMarkSweep Thread for given CMS generation
+ConcurrentMarkSweepThread* ConcurrentMarkSweepThread::start(CMSCollector* collector) {
+  guarantee(_cmst == NULL, "start() called twice!");
+  ConcurrentMarkSweepThread* th = new ConcurrentMarkSweepThread(collector);
+  assert(_cmst == th, "Where did the just-created CMS thread go?");
+  return th;
+}
+
+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();
+}
+
+void ConcurrentMarkSweepThread::threads_do(ThreadClosure* tc) {
+  assert(tc != NULL, "Null ThreadClosure");
+  if (cmst() != NULL && !cmst()->has_terminated()) {
+    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();
+    if (gang != NULL) {
+      gang->threads_do(tc);
+    }
+  }
+}
+
+void ConcurrentMarkSweepThread::print_all_on(outputStream* st) {
+  if (cmst() != NULL && !cmst()->has_terminated()) {
+    cmst()->print_on(st);
+    st->cr();
+  }
+  if (_collector != NULL) {
+    AbstractWorkGang* gang = _collector->conc_workers();
+    if (gang != NULL) {
+      gang->print_worker_threads_on(st);
+    }
+  }
+}
+
+void ConcurrentMarkSweepThread::synchronize(bool is_cms_thread) {
+  assert(UseConcMarkSweepGC, "just checking");
+
+  MutexLockerEx x(CGC_lock,
+                  Mutex::_no_safepoint_check_flag);
+  if (!is_cms_thread) {
+    assert(Thread::current()->is_VM_thread(), "Not a VM thread");
+    CMSSynchronousYieldRequest yr;
+    while (CMS_flag_is_set(CMS_cms_has_token)) {
+      // indicate that we want to get the token
+      set_CMS_flag(CMS_vm_wants_token);
+      CGC_lock->wait(true);
+    }
+    // claim the token and proceed
+    clear_CMS_flag(CMS_vm_wants_token);
+    set_CMS_flag(CMS_vm_has_token);
+  } else {
+    assert(Thread::current()->is_ConcurrentGC_thread(),
+           "Not a CMS thread");
+    // The following barrier assumes there's only one CMS thread.
+    // This will need to be modified is there are more CMS threads than one.
+    while (CMS_flag_is_set(CMS_vm_has_token | CMS_vm_wants_token)) {
+      set_CMS_flag(CMS_cms_wants_token);
+      CGC_lock->wait(true);
+    }
+    // claim the token
+    clear_CMS_flag(CMS_cms_wants_token);
+    set_CMS_flag(CMS_cms_has_token);
+  }
+}
+
+void ConcurrentMarkSweepThread::desynchronize(bool is_cms_thread) {
+  assert(UseConcMarkSweepGC, "just checking");
+
+  MutexLockerEx x(CGC_lock,
+                  Mutex::_no_safepoint_check_flag);
+  if (!is_cms_thread) {
+    assert(Thread::current()->is_VM_thread(), "Not a VM thread");
+    assert(CMS_flag_is_set(CMS_vm_has_token), "just checking");
+    clear_CMS_flag(CMS_vm_has_token);
+    if (CMS_flag_is_set(CMS_cms_wants_token)) {
+      // wake-up a waiting CMS thread
+      CGC_lock->notify();
+    }
+    assert(!CMS_flag_is_set(CMS_vm_has_token | CMS_vm_wants_token),
+           "Should have been cleared");
+  } else {
+    assert(Thread::current()->is_ConcurrentGC_thread(),
+           "Not a CMS thread");
+    assert(CMS_flag_is_set(CMS_cms_has_token), "just checking");
+    clear_CMS_flag(CMS_cms_has_token);
+    if (CMS_flag_is_set(CMS_vm_wants_token)) {
+      // wake-up a waiting VM thread
+      CGC_lock->notify();
+    }
+    assert(!CMS_flag_is_set(CMS_cms_has_token | CMS_cms_wants_token),
+           "Should have been cleared");
+  }
+}
+
+// Wait until any cms_lock event
+void ConcurrentMarkSweepThread::wait_on_cms_lock(long t_millis) {
+  MutexLockerEx x(CGC_lock,
+                  Mutex::_no_safepoint_check_flag);
+  if (should_terminate() || _collector->_full_gc_requested) {
+    return;
+  }
+  set_CMS_flag(CMS_cms_wants_token);   // to provoke notifies
+  CGC_lock->wait(Mutex::_no_safepoint_check_flag, t_millis);
+  clear_CMS_flag(CMS_cms_wants_token);
+  assert(!CMS_flag_is_set(CMS_cms_has_token | CMS_cms_wants_token),
+         "Should not be set");
+}
+
+// Wait until the next synchronous GC, a concurrent full gc request,
+// or a timeout, whichever is earlier.
+void ConcurrentMarkSweepThread::wait_on_cms_lock_for_scavenge(long t_millis) {
+  // Wait time in millis or 0 value representing infinite wait for a scavenge
+  assert(t_millis >= 0, "Wait time for scavenge should be 0 or positive");
+
+  GenCollectedHeap* gch = GenCollectedHeap::heap();
+  double start_time_secs = os::elapsedTime();
+  double end_time_secs = start_time_secs + (t_millis / ((double) MILLIUNITS));
+
+  // Total collections count before waiting loop
+  unsigned int before_count;
+  {
+    MutexLockerEx hl(Heap_lock, Mutex::_no_safepoint_check_flag);
+    before_count = gch->total_collections();
+  }
+
+  unsigned int loop_count = 0;
+
+  while(!should_terminate()) {
+    double now_time = os::elapsedTime();
+    long wait_time_millis;
+
+    if(t_millis != 0) {
+      // New wait limit
+      wait_time_millis = (long) ((end_time_secs - now_time) * MILLIUNITS);
+      if(wait_time_millis <= 0) {
+        // Wait time is over
+        break;
+      }
+    } else {
+      // No wait limit, wait if necessary forever
+      wait_time_millis = 0;
+    }
+
+    // Wait until the next event or the remaining timeout
+    {
+      MutexLockerEx x(CGC_lock, Mutex::_no_safepoint_check_flag);
+
+      if (should_terminate() || _collector->_full_gc_requested) {
+        return;
+      }
+      set_CMS_flag(CMS_cms_wants_token);   // to provoke notifies
+      assert(t_millis == 0 || wait_time_millis > 0, "Sanity");
+      CGC_lock->wait(Mutex::_no_safepoint_check_flag, wait_time_millis);
+      clear_CMS_flag(CMS_cms_wants_token);
+      assert(!CMS_flag_is_set(CMS_cms_has_token | CMS_cms_wants_token),
+             "Should not be set");
+    }
+
+    // Extra wait time check before entering the heap lock to get the collection count
+    if(t_millis != 0 && os::elapsedTime() >= end_time_secs) {
+      // Wait time is over
+      break;
+    }
+
+    // Total collections count after the event
+    unsigned int after_count;
+    {
+      MutexLockerEx hl(Heap_lock, Mutex::_no_safepoint_check_flag);
+      after_count = gch->total_collections();
+    }
+
+    if(before_count != after_count) {
+      // There was a collection - success
+      break;
+    }
+
+    // Too many loops warning
+    if(++loop_count == 0) {
+      log_warning(gc)("wait_on_cms_lock_for_scavenge() has looped %u times", loop_count - 1);
+    }
+  }
+}
+
+void ConcurrentMarkSweepThread::sleepBeforeNextCycle() {
+  while (!should_terminate()) {
+    if(CMSWaitDuration >= 0) {
+      // Wait until the next synchronous GC, a concurrent full gc
+      // request or a timeout, whichever is earlier.
+      wait_on_cms_lock_for_scavenge(CMSWaitDuration);
+    } else {
+      // Wait until any cms_lock event or check interval not to call shouldConcurrentCollect permanently
+      wait_on_cms_lock(CMSCheckInterval);
+    }
+    // Check if we should start a CMS collection cycle
+    if (_collector->shouldConcurrentCollect()) {
+      return;
+    }
+    // .. collection criterion not yet met, let's go back
+    // and wait some more
+  }
+}