1/*
2 * Copyright (c) 2001, 2016, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25#include "precompiled.hpp"
26#include "gc/g1/concurrentG1Refine.hpp"
27#include "gc/g1/concurrentG1RefineThread.hpp"
28#include "gc/g1/g1CollectedHeap.inline.hpp"
29#include "gc/g1/suspendibleThreadSet.hpp"
30#include "logging/log.hpp"
31#include "memory/resourceArea.hpp"
32#include "runtime/handles.inline.hpp"
33#include "runtime/mutexLocker.hpp"
34
35ConcurrentG1RefineThread::
36ConcurrentG1RefineThread(ConcurrentG1Refine* cg1r, ConcurrentG1RefineThread *next,
37                         CardTableEntryClosure* refine_closure,
38                         uint worker_id_offset, uint worker_id,
39                         size_t activate, size_t deactivate) :
40  ConcurrentGCThread(),
41  _refine_closure(refine_closure),
42  _worker_id_offset(worker_id_offset),
43  _worker_id(worker_id),
44  _active(false),
45  _next(next),
46  _monitor(NULL),
47  _cg1r(cg1r),
48  _vtime_accum(0.0),
49  _activation_threshold(activate),
50  _deactivation_threshold(deactivate)
51{
52
53  // Each thread has its own monitor. The i-th thread is responsible for signaling
54  // to thread i+1 if the number of buffers in the queue exceeds a threshold for this
55  // thread. Monitors are also used to wake up the threads during termination.
56  // The 0th (primary) worker is notified by mutator threads and has a special monitor.
57  if (!is_primary()) {
58    _monitor = new Monitor(Mutex::nonleaf, "Refinement monitor", true,
59                           Monitor::_safepoint_check_never);
60  } else {
61    _monitor = DirtyCardQ_CBL_mon;
62  }
63
64  // set name
65  set_name("G1 Refine#%d", worker_id);
66  create_and_start();
67}
68
69void ConcurrentG1RefineThread::update_thresholds(size_t activate,
70                                                 size_t deactivate) {
71  assert(deactivate < activate, "precondition");
72  _activation_threshold = activate;
73  _deactivation_threshold = deactivate;
74}
75
76void ConcurrentG1RefineThread::wait_for_completed_buffers() {
77  MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);
78  while (!should_terminate() && !is_active()) {
79    _monitor->wait(Mutex::_no_safepoint_check_flag);
80  }
81}
82
83bool ConcurrentG1RefineThread::is_active() {
84  DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
85  return is_primary() ? dcqs.process_completed_buffers() : _active;
86}
87
88void ConcurrentG1RefineThread::activate() {
89  MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);
90  if (!is_primary()) {
91    set_active(true);
92  } else {
93    DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
94    dcqs.set_process_completed(true);
95  }
96  _monitor->notify();
97}
98
99void ConcurrentG1RefineThread::deactivate() {
100  MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);
101  if (!is_primary()) {
102    set_active(false);
103  } else {
104    DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
105    dcqs.set_process_completed(false);
106  }
107}
108
109void ConcurrentG1RefineThread::run_service() {
110  _vtime_start = os::elapsedVTime();
111
112  while (!should_terminate()) {
113    // Wait for work
114    wait_for_completed_buffers();
115    if (should_terminate()) {
116      break;
117    }
118
119    size_t buffers_processed = 0;
120    DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
121    log_debug(gc, refine)("Activated %d, on threshold: " SIZE_FORMAT ", current: " SIZE_FORMAT,
122                          _worker_id, _activation_threshold, dcqs.completed_buffers_num());
123
124    {
125      SuspendibleThreadSetJoiner sts_join;
126
127      while (!should_terminate()) {
128        if (sts_join.should_yield()) {
129          sts_join.yield();
130          continue;             // Re-check for termination after yield delay.
131        }
132
133        size_t curr_buffer_num = dcqs.completed_buffers_num();
134        // If the number of the buffers falls down into the yellow zone,
135        // that means that the transition period after the evacuation pause has ended.
136        if (dcqs.completed_queue_padding() > 0 && curr_buffer_num <= cg1r()->yellow_zone()) {
137          dcqs.set_completed_queue_padding(0);
138        }
139
140        // Check if we need to activate the next thread.
141        if ((_next != NULL) &&
142            !_next->is_active() &&
143            (curr_buffer_num > _next->_activation_threshold)) {
144          _next->activate();
145        }
146
147        // Process the next buffer, if there are enough left.
148        if (!dcqs.apply_closure_to_completed_buffer(_refine_closure,
149                                                    _worker_id + _worker_id_offset,
150                                                    _deactivation_threshold,
151                                                    false /* during_pause */)) {
152          break; // Deactivate, number of buffers fell below threshold.
153        }
154        ++buffers_processed;
155      }
156    }
157
158    deactivate();
159    log_debug(gc, refine)("Deactivated %d, off threshold: " SIZE_FORMAT
160                          ", current: " SIZE_FORMAT ", processed: " SIZE_FORMAT,
161                          _worker_id, _deactivation_threshold,
162                          dcqs.completed_buffers_num(),
163                          buffers_processed);
164
165    if (os::supports_vtime()) {
166      _vtime_accum = (os::elapsedVTime() - _vtime_start);
167    } else {
168      _vtime_accum = 0.0;
169    }
170  }
171
172  log_debug(gc, refine)("Stopping %d", _worker_id);
173}
174
175void ConcurrentG1RefineThread::stop_service() {
176  MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);
177  _monitor->notify();
178}
179