3789983e89
Reviewed-by: darcy, ihse
122 lines
3.9 KiB
C++
122 lines
3.9 KiB
C++
/*
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* Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*
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*/
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#include "precompiled.hpp"
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#include "gc/g1/g1CollectedHeap.inline.hpp"
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#include "gc/g1/g1CollectionSet.hpp"
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#include "gc/g1/g1Policy.hpp"
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#include "gc/g1/g1YoungRemSetSamplingThread.hpp"
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#include "gc/g1/heapRegion.inline.hpp"
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#include "gc/g1/heapRegionRemSet.hpp"
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#include "gc/g1/suspendibleThreadSet.hpp"
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#include "runtime/mutexLocker.hpp"
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G1YoungRemSetSamplingThread::G1YoungRemSetSamplingThread() :
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ConcurrentGCThread(),
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_monitor(Mutex::nonleaf,
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"G1YoungRemSetSamplingThread monitor",
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true,
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Monitor::_safepoint_check_never) {
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set_name("G1 Young RemSet Sampling");
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create_and_start();
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}
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void G1YoungRemSetSamplingThread::sleep_before_next_cycle() {
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MutexLockerEx x(&_monitor, Mutex::_no_safepoint_check_flag);
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if (!should_terminate()) {
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uintx waitms = G1ConcRefinementServiceIntervalMillis; // 300, really should be?
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_monitor.wait(Mutex::_no_safepoint_check_flag, waitms);
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}
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}
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void G1YoungRemSetSamplingThread::run_service() {
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double vtime_start = os::elapsedVTime();
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while (!should_terminate()) {
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sample_young_list_rs_lengths();
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if (os::supports_vtime()) {
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_vtime_accum = (os::elapsedVTime() - vtime_start);
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} else {
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_vtime_accum = 0.0;
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}
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sleep_before_next_cycle();
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}
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}
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void G1YoungRemSetSamplingThread::stop_service() {
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MutexLockerEx x(&_monitor, Mutex::_no_safepoint_check_flag);
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_monitor.notify();
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}
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class G1YoungRemSetSamplingClosure : public HeapRegionClosure {
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SuspendibleThreadSetJoiner* _sts;
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size_t _regions_visited;
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size_t _sampled_rs_lengths;
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public:
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G1YoungRemSetSamplingClosure(SuspendibleThreadSetJoiner* sts) :
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HeapRegionClosure(), _sts(sts), _regions_visited(0), _sampled_rs_lengths(0) { }
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virtual bool doHeapRegion(HeapRegion* r) {
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size_t rs_length = r->rem_set()->occupied();
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_sampled_rs_lengths += rs_length;
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// Update the collection set policy information for this region
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G1CollectedHeap::heap()->collection_set()->update_young_region_prediction(r, rs_length);
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_regions_visited++;
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if (_regions_visited == 10) {
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if (_sts->should_yield()) {
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_sts->yield();
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// A gc may have occurred and our sampling data is stale and further
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// traversal of the collection set is unsafe
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return true;
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}
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_regions_visited = 0;
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}
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return false;
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}
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size_t sampled_rs_lengths() const { return _sampled_rs_lengths; }
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};
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void G1YoungRemSetSamplingThread::sample_young_list_rs_lengths() {
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SuspendibleThreadSetJoiner sts;
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G1CollectedHeap* g1h = G1CollectedHeap::heap();
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G1Policy* g1p = g1h->g1_policy();
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if (g1p->adaptive_young_list_length()) {
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G1YoungRemSetSamplingClosure cl(&sts);
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G1CollectionSet* g1cs = g1h->collection_set();
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g1cs->iterate(&cl);
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if (cl.complete()) {
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g1p->revise_young_list_target_length_if_necessary(cl.sampled_rs_lengths());
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}
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}
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}
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