1 /*
2 * Copyright (c) 2013, 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 #include "gc_interface/gcCause.hpp"
26 #include "gc_implementation/shared/gcTimer.hpp"
27 #include "gc_implementation/shenandoah/shenandoahCollectionSet.hpp"
28 #include "gc_implementation/shenandoah/shenandoahCollectorPolicy.hpp"
29 #include "gc_implementation/shenandoah/shenandoahHeap.inline.hpp"
30 #include "gc_implementation/shenandoah/shenandoahLogging.hpp"
31 #include "gc_implementation/shenandoah/heuristics/shenandoahHeuristics.hpp"
32
33 ShenandoahCollectorPolicy::ShenandoahCollectorPolicy() :
34 _success_concurrent_gcs(0),
35 _success_degenerated_gcs(0),
36 _success_full_gcs(0),
37 _alloc_failure_degenerated(0),
38 _alloc_failure_full(0),
39 _alloc_failure_degenerated_upgrade_to_full(0),
40 _explicit_concurrent(0),
41 _explicit_full(0),
42 _implicit_concurrent(0),
43 _implicit_full(0),
44 _cycle_counter(0) {
45
46 Copy::zero_to_bytes(_degen_points, sizeof(size_t) * ShenandoahHeap::_DEGENERATED_LIMIT);
47
48 ShenandoahHeapRegion::setup_sizes(max_heap_byte_size());
49
50 initialize_all();
51
52 _tracer = new (ResourceObj::C_HEAP, mtGC) ShenandoahTracer();
53 }
54
55 BarrierSet::Name ShenandoahCollectorPolicy::barrier_set_name() {
56 return BarrierSet::ShenandoahBarrierSet;
57 }
58
59 HeapWord* ShenandoahCollectorPolicy::mem_allocate_work(size_t size,
60 bool is_tlab,
61 bool* gc_overhead_limit_was_exceeded) {
62 guarantee(false, "Not using this policy feature yet.");
63 return NULL;
64 }
65
66 HeapWord* ShenandoahCollectorPolicy::satisfy_failed_allocation(size_t size, bool is_tlab) {
67 guarantee(false, "Not using this policy feature yet.");
68 return NULL;
69 }
70
71 MetaWord* ShenandoahCollectorPolicy::satisfy_failed_metadata_allocation(ClassLoaderData *loader_data,
72 size_t size,
73 Metaspace::MetadataType mdtype) {
74 MetaWord* result;
75
76 ShenandoahHeap* sh = ShenandoahHeap::heap();
77
78 // Inform metaspace OOM to GC heuristics if class unloading is possible.
79 ShenandoahHeuristics* h = sh->heuristics();
80 if (h->can_unload_classes()) {
81 h->record_metaspace_oom();
82 }
83
84 // Expand and retry allocation
85 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
86 if (result != NULL) {
87 return result;
88 }
89
90 // Start full GC
91 sh->collect(GCCause::_shenandoah_metadata_gc_clear_softrefs);
92
93 // Retry allocation
94 result = loader_data->metaspace_non_null()->allocate(size, mdtype);
95 if (result != NULL) {
96 return result;
97 }
98
99 // Expand and retry allocation
100 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
101 if (result != NULL) {
102 return result;
103 }
104
105 // Out of memory
106 return NULL;
107 }
108
109 void ShenandoahCollectorPolicy::initialize_alignments() {
110 // This is expected by our algorithm for ShenandoahHeap::heap_region_containing().
111 size_t align = ShenandoahHeapRegion::region_size_bytes();
112 if (UseLargePages) {
113 align = MAX2(align, os::large_page_size());
114 }
115 _space_alignment = align;
116 _heap_alignment = align;
117 }
118
119 void ShenandoahCollectorPolicy::record_explicit_to_concurrent() {
120 _explicit_concurrent++;
121 }
122
123 void ShenandoahCollectorPolicy::record_explicit_to_full() {
124 _explicit_full++;
125 }
126
127 void ShenandoahCollectorPolicy::record_implicit_to_concurrent() {
128 _implicit_concurrent++;
129 }
130
131 void ShenandoahCollectorPolicy::record_implicit_to_full() {
132 _implicit_full++;
133 }
134
135 void ShenandoahCollectorPolicy::record_alloc_failure_to_full() {
136 _alloc_failure_full++;
137 }
138
139 void ShenandoahCollectorPolicy::record_alloc_failure_to_degenerated(ShenandoahHeap::ShenandoahDegenPoint point) {
140 assert(point < ShenandoahHeap::_DEGENERATED_LIMIT, "sanity");
141 _alloc_failure_degenerated++;
142 _degen_points[point]++;
143 }
144
145 void ShenandoahCollectorPolicy::record_degenerated_upgrade_to_full() {
146 _alloc_failure_degenerated_upgrade_to_full++;
147 }
148
149 void ShenandoahCollectorPolicy::record_success_concurrent() {
150 _success_concurrent_gcs++;
151 }
152
153 void ShenandoahCollectorPolicy::record_success_degenerated() {
154 _success_degenerated_gcs++;
155 }
156
157 void ShenandoahCollectorPolicy::record_success_full() {
158 _success_full_gcs++;
159 }
160
161 size_t ShenandoahCollectorPolicy::cycle_counter() const {
162 return _cycle_counter;
163 }
164
165 void ShenandoahCollectorPolicy::record_cycle_start() {
166 _cycle_counter++;
167 }
168
169 void ShenandoahCollectorPolicy::record_shutdown() {
170 _in_shutdown.set();
171 }
172
173 bool ShenandoahCollectorPolicy::is_at_shutdown() {
174 return _in_shutdown.is_set();
175 }
176
177 void ShenandoahCollectorPolicy::print_gc_stats(outputStream* out) const {
178 out->print_cr("Under allocation pressure, concurrent cycles may cancel, and either continue cycle");
179 out->print_cr("under stop-the-world pause or result in stop-the-world Full GC. Increase heap size,");
180 out->print_cr("tune GC heuristics, set more aggressive pacing delay, or lower allocation rate");
181 out->print_cr("to avoid Degenerated and Full GC cycles.");
182 out->cr();
183
184 out->print_cr(SIZE_FORMAT_W(5) " successful concurrent GCs", _success_concurrent_gcs);
185 out->print_cr(" " SIZE_FORMAT_W(5) " invoked explicitly", _explicit_concurrent);
186 out->print_cr(" " SIZE_FORMAT_W(5) " invoked implicitly", _implicit_concurrent);
187 out->cr();
188
189 out->print_cr(SIZE_FORMAT_W(5) " Degenerated GCs", _success_degenerated_gcs);
190 out->print_cr(" " SIZE_FORMAT_W(5) " caused by allocation failure", _alloc_failure_degenerated);
191 for (int c = 0; c < ShenandoahHeap::_DEGENERATED_LIMIT; c++) {
192 if (_degen_points[c] > 0) {
193 const char* desc = ShenandoahHeap::degen_point_to_string((ShenandoahHeap::ShenandoahDegenPoint)c);
194 out->print_cr(" " SIZE_FORMAT_W(5) " happened at %s", _degen_points[c], desc);
195 }
196 }
197 out->print_cr(" " SIZE_FORMAT_W(5) " upgraded to Full GC", _alloc_failure_degenerated_upgrade_to_full);
198 out->cr();
199
200 out->print_cr(SIZE_FORMAT_W(5) " Full GCs", _success_full_gcs + _alloc_failure_degenerated_upgrade_to_full);
201 out->print_cr(" " SIZE_FORMAT_W(5) " invoked explicitly", _explicit_full);
202 out->print_cr(" " SIZE_FORMAT_W(5) " invoked implicitly", _implicit_full);
203 out->print_cr(" " SIZE_FORMAT_W(5) " caused by allocation failure", _alloc_failure_full);
204 out->print_cr(" " SIZE_FORMAT_W(5) " upgraded from Degenerated GC", _alloc_failure_degenerated_upgrade_to_full);
205 }