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/shenandoahCollectionSet.hpp"
27#include "gc/shenandoah/heuristics/shenandoahCompactHeuristics.hpp"
28#include "gc/shenandoah/shenandoahFreeSet.hpp"
29#include "gc/shenandoah/shenandoahHeapRegion.hpp"
30#include "logging/log.hpp"
31#include "logging/logTag.hpp"
32
33ShenandoahCompactHeuristics::ShenandoahCompactHeuristics() : ShenandoahHeuristics() {
34 SHENANDOAH_ERGO_ENABLE_FLAG(ExplicitGCInvokesConcurrent);
35 SHENANDOAH_ERGO_ENABLE_FLAG(ShenandoahImplicitGCInvokesConcurrent);
36 SHENANDOAH_ERGO_ENABLE_FLAG(ShenandoahUncommit);
37 SHENANDOAH_ERGO_ENABLE_FLAG(ShenandoahAlwaysClearSoftRefs);
38 SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahAllocationThreshold, 10);
39 SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahImmediateThreshold, 100);
40 SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahUncommitDelay, 1000);
41 SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahGuaranteedGCInterval, 30000);
42 SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahGarbageThreshold, 10);
43
44 // Final configuration checks
45 SHENANDOAH_CHECK_FLAG_SET(ShenandoahLoadRefBarrier);
46 SHENANDOAH_CHECK_FLAG_SET(ShenandoahSATBBarrier);
47 SHENANDOAH_CHECK_FLAG_SET(ShenandoahKeepAliveBarrier);
48 SHENANDOAH_CHECK_FLAG_SET(ShenandoahCASBarrier);
49 SHENANDOAH_CHECK_FLAG_SET(ShenandoahCloneBarrier);
50}
51
52bool ShenandoahCompactHeuristics::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
58 size_t threshold_bytes_allocated = capacity / 100 * ShenandoahAllocationThreshold;
59 size_t min_threshold = capacity / 100 * ShenandoahMinFreeThreshold;
60
61 if (available < min_threshold) {
62 log_info(gc)("Trigger: Free (" SIZE_FORMAT "M) is below minimum threshold (" SIZE_FORMAT "M)",
63 available / M, min_threshold / M);
64 return true;
65 }
66
67 if (available < threshold_bytes_allocated) {
68 log_info(gc)("Trigger: Free (" SIZE_FORMAT "M) is lower than allocated recently (" SIZE_FORMAT "M)",
69 available / M, threshold_bytes_allocated / M);
70 return true;
71 }
72
73 size_t bytes_allocated = heap->bytes_allocated_since_gc_start();
74 if (bytes_allocated > threshold_bytes_allocated) {
75 log_info(gc)("Trigger: Allocated since last cycle (" SIZE_FORMAT "M) is larger than allocation threshold (" SIZE_FORMAT "M)",
76 bytes_allocated / M, threshold_bytes_allocated / M);
77 return true;
78 }
79
80 return ShenandoahHeuristics::should_start_normal_gc();
81}
82
83void ShenandoahCompactHeuristics::choose_collection_set_from_regiondata(ShenandoahCollectionSet* cset,
84 RegionData* data, size_t size,
85 size_t actual_free) {
86 // Do not select too large CSet that would overflow the available free space
87 size_t max_cset = actual_free * 3 / 4;
88
89 log_info(gc, ergo)("CSet Selection. Actual Free: " SIZE_FORMAT "M, Max CSet: " SIZE_FORMAT "M",
90 actual_free / M, max_cset / M);
91
92 size_t threshold = ShenandoahHeapRegion::region_size_bytes() * ShenandoahGarbageThreshold / 100;
93
94 size_t live_cset = 0;
95 for (size_t idx = 0; idx < size; idx++) {
96 ShenandoahHeapRegion* r = data[idx]._region;
97 size_t new_cset = live_cset + r->get_live_data_bytes();
98 if (new_cset < max_cset && r->garbage() > threshold) {
99 live_cset = new_cset;
100 cset->add_region(r);
101 }
102 }
103}
104
105const char* ShenandoahCompactHeuristics::name() {
106 return "compact";
107}
108
109bool ShenandoahCompactHeuristics::is_diagnostic() {
110 return false;
111}
112
113bool ShenandoahCompactHeuristics::is_experimental() {
114 return false;
115}
116