src/hotspot/share/gc/g1/g1ConcurrentRefineThread.cpp
changeset 47789 a77a7d3bc4f6
parent 47647 64dba69fc528
child 48103 26dbe08d1c17
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/g1/g1ConcurrentRefineThread.cpp	Mon Nov 06 14:24:31 2017 +0100
@@ -0,0 +1,176 @@
+/*
+ * Copyright (c) 2001, 2017, 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 "gc/g1/g1ConcurrentRefine.hpp"
+#include "gc/g1/g1ConcurrentRefineThread.hpp"
+#include "gc/g1/g1CollectedHeap.inline.hpp"
+#include "gc/g1/g1RemSet.hpp"
+#include "gc/shared/suspendibleThreadSet.hpp"
+#include "logging/log.hpp"
+#include "memory/resourceArea.hpp"
+#include "runtime/handles.inline.hpp"
+#include "runtime/mutexLocker.hpp"
+
+G1ConcurrentRefineThread::G1ConcurrentRefineThread(G1ConcurrentRefine* cr,
+                                                   G1ConcurrentRefineThread *next,
+                                                   uint worker_id_offset,
+                                                   uint worker_id,
+                                                   size_t activate,
+                                                   size_t deactivate) :
+  ConcurrentGCThread(),
+  _worker_id_offset(worker_id_offset),
+  _worker_id(worker_id),
+  _active(false),
+  _next(next),
+  _monitor(NULL),
+  _cr(cr),
+  _vtime_accum(0.0),
+  _activation_threshold(activate),
+  _deactivation_threshold(deactivate)
+{
+
+  // Each thread has its own monitor. The i-th thread is responsible for signaling
+  // to thread i+1 if the number of buffers in the queue exceeds a threshold for this
+  // thread. Monitors are also used to wake up the threads during termination.
+  // The 0th (primary) worker is notified by mutator threads and has a special monitor.
+  if (!is_primary()) {
+    _monitor = new Monitor(Mutex::nonleaf, "Refinement monitor", true,
+                           Monitor::_safepoint_check_never);
+  } else {
+    _monitor = DirtyCardQ_CBL_mon;
+  }
+
+  // set name
+  set_name("G1 Refine#%d", worker_id);
+  create_and_start();
+}
+
+void G1ConcurrentRefineThread::update_thresholds(size_t activate,
+                                                 size_t deactivate) {
+  assert(deactivate < activate, "precondition");
+  _activation_threshold = activate;
+  _deactivation_threshold = deactivate;
+}
+
+void G1ConcurrentRefineThread::wait_for_completed_buffers() {
+  MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);
+  while (!should_terminate() && !is_active()) {
+    _monitor->wait(Mutex::_no_safepoint_check_flag);
+  }
+}
+
+bool G1ConcurrentRefineThread::is_active() {
+  DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
+  return is_primary() ? dcqs.process_completed_buffers() : _active;
+}
+
+void G1ConcurrentRefineThread::activate() {
+  MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);
+  if (!is_primary()) {
+    set_active(true);
+  } else {
+    DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
+    dcqs.set_process_completed(true);
+  }
+  _monitor->notify();
+}
+
+void G1ConcurrentRefineThread::deactivate() {
+  MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);
+  if (!is_primary()) {
+    set_active(false);
+  } else {
+    DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
+    dcqs.set_process_completed(false);
+  }
+}
+
+void G1ConcurrentRefineThread::run_service() {
+  _vtime_start = os::elapsedVTime();
+
+  while (!should_terminate()) {
+    // Wait for work
+    wait_for_completed_buffers();
+    if (should_terminate()) {
+      break;
+    }
+
+    size_t buffers_processed = 0;
+    DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
+    log_debug(gc, refine)("Activated %d, on threshold: " SIZE_FORMAT ", current: " SIZE_FORMAT,
+                          _worker_id, _activation_threshold, dcqs.completed_buffers_num());
+
+    {
+      SuspendibleThreadSetJoiner sts_join;
+
+      while (!should_terminate()) {
+        if (sts_join.should_yield()) {
+          sts_join.yield();
+          continue;             // Re-check for termination after yield delay.
+        }
+
+        size_t curr_buffer_num = dcqs.completed_buffers_num();
+        // If the number of the buffers falls down into the yellow zone,
+        // that means that the transition period after the evacuation pause has ended.
+        if (dcqs.completed_queue_padding() > 0 && curr_buffer_num <= cr()->yellow_zone()) {
+          dcqs.set_completed_queue_padding(0);
+        }
+
+        // Check if we need to activate the next thread.
+        if ((_next != NULL) &&
+            !_next->is_active() &&
+            (curr_buffer_num > _next->_activation_threshold)) {
+          _next->activate();
+        }
+
+        // Process the next buffer, if there are enough left.
+        if (!dcqs.refine_completed_buffer_concurrently(_worker_id + _worker_id_offset, _deactivation_threshold)) {
+          break; // Deactivate, number of buffers fell below threshold.
+        }
+        ++buffers_processed;
+      }
+    }
+
+    deactivate();
+    log_debug(gc, refine)("Deactivated %d, off threshold: " SIZE_FORMAT
+                          ", current: " SIZE_FORMAT ", processed: " SIZE_FORMAT,
+                          _worker_id, _deactivation_threshold,
+                          dcqs.completed_buffers_num(),
+                          buffers_processed);
+
+    if (os::supports_vtime()) {
+      _vtime_accum = (os::elapsedVTime() - _vtime_start);
+    } else {
+      _vtime_accum = 0.0;
+    }
+  }
+
+  log_debug(gc, refine)("Stopping %d", _worker_id);
+}
+
+void G1ConcurrentRefineThread::stop_service() {
+  MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);
+  _monitor->notify();
+}