1/*
2 * Copyright (c) 2018, Red Hat, Inc. All rights reserved.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24#include "precompiled.hpp"
25
26#include "gc/shenandoah/heuristics/shenandoahStaticHeuristics.hpp"
27#include "gc/shenandoah/shenandoahCollectionSet.hpp"
28#include "gc/shenandoah/shenandoahFreeSet.hpp"
29#include "gc/shenandoah/shenandoahHeapRegion.hpp"
30#include "logging/log.hpp"
31#include "logging/logTag.hpp"
32
33ShenandoahStaticHeuristics::ShenandoahStaticHeuristics() : ShenandoahHeuristics() {
34 // Static heuristics may degrade to continuous if live data is larger
35 // than free threshold. ShenandoahAllocationThreshold is supposed to break this,
36 // but it only works if it is non-zero.
37 SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahAllocationThreshold, 1);
38
39 SHENANDOAH_ERGO_ENABLE_FLAG(ExplicitGCInvokesConcurrent);
40 SHENANDOAH_ERGO_ENABLE_FLAG(ShenandoahImplicitGCInvokesConcurrent);
41
42 // Final configuration checks
43 SHENANDOAH_CHECK_FLAG_SET(ShenandoahLoadRefBarrier);
44 SHENANDOAH_CHECK_FLAG_SET(ShenandoahSATBBarrier);
45 SHENANDOAH_CHECK_FLAG_SET(ShenandoahKeepAliveBarrier);
46 SHENANDOAH_CHECK_FLAG_SET(ShenandoahCASBarrier);
47 SHENANDOAH_CHECK_FLAG_SET(ShenandoahCloneBarrier);
48}
49
50ShenandoahStaticHeuristics::~ShenandoahStaticHeuristics() {}
51
52bool ShenandoahStaticHeuristics::should_start_normal_gc() const {
53 ShenandoahHeap* heap = ShenandoahHeap::heap();
54
55 size_t capacity = heap->max_capacity();
56 size_t available = heap->free_set()->available();
57 size_t threshold_available = capacity / 100 * ShenandoahFreeThreshold;
58
59 if (available < threshold_available) {
60 log_info(gc)("Trigger: Free (" SIZE_FORMAT "M) is below free threshold (" SIZE_FORMAT "M)",
61 available / M, threshold_available / M);
62 return true;
63 }
64 return ShenandoahHeuristics::should_start_normal_gc();
65}
66
67void ShenandoahStaticHeuristics::choose_collection_set_from_regiondata(ShenandoahCollectionSet* cset,
68 RegionData* data, size_t size,
69 size_t free) {
70 size_t threshold = ShenandoahHeapRegion::region_size_bytes() * ShenandoahGarbageThreshold / 100;
71
72 for (size_t idx = 0; idx < size; idx++) {
73 ShenandoahHeapRegion* r = data[idx]._region;
74 if (r->garbage() > threshold) {
75 cset->add_region(r);
76 }
77 }
78}
79
80const char* ShenandoahStaticHeuristics::name() {
81 return "static";
82}
83
84bool ShenandoahStaticHeuristics::is_diagnostic() {
85 return false;
86}
87
88bool ShenandoahStaticHeuristics::is_experimental() {
89 return false;
90}
91