--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc/g1/concurrentG1RefineThread.cpp Wed May 13 15:16:06 2015 +0200
@@ -0,0 +1,253 @@
+/*
+ * Copyright (c) 2001, 2015, 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/concurrentG1Refine.hpp"
+#include "gc/g1/concurrentG1RefineThread.hpp"
+#include "gc/g1/g1CollectedHeap.inline.hpp"
+#include "gc/g1/g1CollectorPolicy.hpp"
+#include "memory/resourceArea.hpp"
+#include "runtime/handles.inline.hpp"
+#include "runtime/mutexLocker.hpp"
+
+ConcurrentG1RefineThread::
+ConcurrentG1RefineThread(ConcurrentG1Refine* cg1r, ConcurrentG1RefineThread *next,
+ CardTableEntryClosure* refine_closure,
+ uint worker_id_offset, uint worker_id) :
+ ConcurrentGCThread(),
+ _refine_closure(refine_closure),
+ _worker_id_offset(worker_id_offset),
+ _worker_id(worker_id),
+ _active(false),
+ _next(next),
+ _monitor(NULL),
+ _cg1r(cg1r),
+ _vtime_accum(0.0)
+{
+
+ // 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 worker in notified by mutator threads and has a special monitor.
+ // The last worker is used for young gen rset size sampling.
+ if (worker_id > 0) {
+ _monitor = new Monitor(Mutex::nonleaf, "Refinement monitor", true,
+ Monitor::_safepoint_check_never);
+ } else {
+ _monitor = DirtyCardQ_CBL_mon;
+ }
+ initialize();
+ create_and_start();
+
+ // set name
+ set_name("G1 Refine#%d", worker_id);
+}
+
+void ConcurrentG1RefineThread::initialize() {
+ if (_worker_id < cg1r()->worker_thread_num()) {
+ // Current thread activation threshold
+ _threshold = MIN2<int>(cg1r()->thread_threshold_step() * (_worker_id + 1) + cg1r()->green_zone(),
+ cg1r()->yellow_zone());
+ // A thread deactivates once the number of buffer reached a deactivation threshold
+ _deactivation_threshold = MAX2<int>(_threshold - cg1r()->thread_threshold_step(), cg1r()->green_zone());
+ } else {
+ set_active(true);
+ }
+}
+
+void ConcurrentG1RefineThread::sample_young_list_rs_lengths() {
+ SuspendibleThreadSetJoiner sts_join;
+ G1CollectedHeap* g1h = G1CollectedHeap::heap();
+ G1CollectorPolicy* g1p = g1h->g1_policy();
+ if (g1p->adaptive_young_list_length()) {
+ int regions_visited = 0;
+ g1h->young_list()->rs_length_sampling_init();
+ while (g1h->young_list()->rs_length_sampling_more()) {
+ g1h->young_list()->rs_length_sampling_next();
+ ++regions_visited;
+
+ // we try to yield every time we visit 10 regions
+ if (regions_visited == 10) {
+ if (sts_join.should_yield()) {
+ sts_join.yield();
+ // we just abandon the iteration
+ break;
+ }
+ regions_visited = 0;
+ }
+ }
+
+ g1p->revise_young_list_target_length_if_necessary();
+ }
+}
+
+void ConcurrentG1RefineThread::run_young_rs_sampling() {
+ DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
+ _vtime_start = os::elapsedVTime();
+ while(!_should_terminate) {
+ sample_young_list_rs_lengths();
+
+ if (os::supports_vtime()) {
+ _vtime_accum = (os::elapsedVTime() - _vtime_start);
+ } else {
+ _vtime_accum = 0.0;
+ }
+
+ MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);
+ if (_should_terminate) {
+ break;
+ }
+ _monitor->wait(Mutex::_no_safepoint_check_flag, G1ConcRefinementServiceIntervalMillis);
+ }
+}
+
+void ConcurrentG1RefineThread::wait_for_completed_buffers() {
+ DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
+ MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);
+ while (!_should_terminate && !is_active()) {
+ _monitor->wait(Mutex::_no_safepoint_check_flag);
+ }
+}
+
+bool ConcurrentG1RefineThread::is_active() {
+ DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
+ return _worker_id > 0 ? _active : dcqs.process_completed_buffers();
+}
+
+void ConcurrentG1RefineThread::activate() {
+ MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);
+ if (_worker_id > 0) {
+ if (G1TraceConcRefinement) {
+ DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
+ gclog_or_tty->print_cr("G1-Refine-activated worker %d, on threshold %d, current %d",
+ _worker_id, _threshold, (int)dcqs.completed_buffers_num());
+ }
+ set_active(true);
+ } else {
+ DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
+ dcqs.set_process_completed(true);
+ }
+ _monitor->notify();
+}
+
+void ConcurrentG1RefineThread::deactivate() {
+ MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);
+ if (_worker_id > 0) {
+ if (G1TraceConcRefinement) {
+ DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
+ gclog_or_tty->print_cr("G1-Refine-deactivated worker %d, off threshold %d, current %d",
+ _worker_id, _deactivation_threshold, (int)dcqs.completed_buffers_num());
+ }
+ set_active(false);
+ } else {
+ DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
+ dcqs.set_process_completed(false);
+ }
+}
+
+void ConcurrentG1RefineThread::run() {
+ initialize_in_thread();
+ wait_for_universe_init();
+
+ if (_worker_id >= cg1r()->worker_thread_num()) {
+ run_young_rs_sampling();
+ terminate();
+ return;
+ }
+
+ _vtime_start = os::elapsedVTime();
+ while (!_should_terminate) {
+ DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
+
+ // Wait for work
+ wait_for_completed_buffers();
+
+ if (_should_terminate) {
+ break;
+ }
+
+ {
+ SuspendibleThreadSetJoiner sts_join;
+
+ do {
+ int curr_buffer_num = (int)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 <= cg1r()->yellow_zone()) {
+ dcqs.set_completed_queue_padding(0);
+ }
+
+ if (_worker_id > 0 && curr_buffer_num <= _deactivation_threshold) {
+ // If the number of the buffer has fallen below our threshold
+ // we should deactivate. The predecessor will reactivate this
+ // thread should the number of the buffers cross the threshold again.
+ deactivate();
+ break;
+ }
+
+ // Check if we need to activate the next thread.
+ if (_next != NULL && !_next->is_active() && curr_buffer_num > _next->_threshold) {
+ _next->activate();
+ }
+ } while (dcqs.apply_closure_to_completed_buffer(_refine_closure, _worker_id + _worker_id_offset, cg1r()->green_zone()));
+
+ // We can exit the loop above while being active if there was a yield request.
+ if (is_active()) {
+ deactivate();
+ }
+ }
+
+ if (os::supports_vtime()) {
+ _vtime_accum = (os::elapsedVTime() - _vtime_start);
+ } else {
+ _vtime_accum = 0.0;
+ }
+ }
+ assert(_should_terminate, "just checking");
+ terminate();
+}
+
+void ConcurrentG1RefineThread::stop() {
+ // it is ok to take late safepoints here, if needed
+ {
+ MutexLockerEx mu(Terminator_lock);
+ _should_terminate = true;
+ }
+
+ {
+ MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);
+ _monitor->notify();
+ }
+
+ {
+ MutexLockerEx mu(Terminator_lock);
+ while (!_has_terminated) {
+ Terminator_lock->wait();
+ }
+ }
+ if (G1TraceConcRefinement) {
+ gclog_or_tty->print_cr("G1-Refine-stop");
+ }
+}
+