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.hpp"
30 #include "gc_implementation/shenandoah/shenandoahHeap.inline.hpp"
31 #include "gc_implementation/shenandoah/shenandoahHeuristics.hpp"
32 #include "gc_implementation/shenandoah/shenandoahLogging.hpp"
33
34 ShenandoahCollectorPolicy::ShenandoahCollectorPolicy() :
35 _success_concurrent_gcs(0),
36 _success_degenerated_gcs(0),
37 _success_full_gcs(0),
38 _alloc_failure_degenerated(0),
39 _alloc_failure_full(0),
40 _alloc_failure_degenerated_upgrade_to_full(0),
41 _explicit_concurrent(0),
42 _explicit_full(0),
43 _implicit_concurrent(0),
44 _implicit_full(0),
45 _cycle_counter(0) {
46
47 Copy::zero_to_bytes(_degen_points, sizeof(size_t) * ShenandoahHeap::_DEGENERATED_LIMIT);
48
49 ShenandoahHeapRegion::setup_sizes(initial_heap_byte_size(), max_heap_byte_size());
50
51 initialize_all();
52
53 _tracer = new (ResourceObj::C_HEAP, mtGC) ShenandoahTracer();
54 }
55
56 BarrierSet::Name ShenandoahCollectorPolicy::barrier_set_name() {
57 return BarrierSet::ShenandoahBarrierSet;
58 }
59
60 HeapWord* ShenandoahCollectorPolicy::mem_allocate_work(size_t size,
61 bool is_tlab,
62 bool* gc_overhead_limit_was_exceeded) {
63 guarantee(false, "Not using this policy feature yet.");
64 return NULL;
65 }
66
67 HeapWord* ShenandoahCollectorPolicy::satisfy_failed_allocation(size_t size, bool is_tlab) {
68 guarantee(false, "Not using this policy feature yet.");
69 return NULL;
70 }
71
72 MetaWord* ShenandoahCollectorPolicy::satisfy_failed_metadata_allocation(ClassLoaderData *loader_data,
73 size_t size,
74 Metaspace::MetadataType mdtype) {
75 MetaWord* result;
76
77 ShenandoahHeap* sh = ShenandoahHeap::heap();
78
79 // Inform metaspace OOM to GC heuristics if class unloading is possible.
80 ShenandoahHeuristics* h = sh->heuristics();
81 if (h->can_unload_classes()) {
82 h->record_metaspace_oom();
83 }
84
85 // Expand and retry allocation
86 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
87 if (result != NULL) {
88 return result;
89 }
90
91 // Start full GC
92 sh->collect(GCCause::_shenandoah_metadata_gc_clear_softrefs);
93
94 // Retry allocation
95 result = loader_data->metaspace_non_null()->allocate(size, mdtype);
96 if (result != NULL) {
97 return result;
98 }
99
100 // Expand and retry allocation
101 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
102 if (result != NULL) {
103 return result;
104 }
105
106 // Out of memory
107 return NULL;
108 }
109
110 void ShenandoahCollectorPolicy::initialize_alignments() {
111 // This is expected by our algorithm for ShenandoahHeap::heap_region_containing().
112 size_t align = ShenandoahHeapRegion::region_size_bytes();
113 if (UseLargePages) {
114 align = MAX2(align, os::large_page_size());
115 }
116 _space_alignment = align;
117 _heap_alignment = align;
118 }
119
120 void ShenandoahCollectorPolicy::record_explicit_to_concurrent() {
121 _explicit_concurrent++;
122 }
123
124 void ShenandoahCollectorPolicy::record_explicit_to_full() {
125 _explicit_full++;
126 }
127
128 void ShenandoahCollectorPolicy::record_implicit_to_concurrent() {
129 _implicit_concurrent++;
130 }
131
132 void ShenandoahCollectorPolicy::record_implicit_to_full() {
133 _implicit_full++;
134 }
135
136 void ShenandoahCollectorPolicy::record_alloc_failure_to_full() {
137 _alloc_failure_full++;
138 }
139
140 void ShenandoahCollectorPolicy::record_alloc_failure_to_degenerated(ShenandoahHeap::ShenandoahDegenPoint point) {
141 assert(point < ShenandoahHeap::_DEGENERATED_LIMIT, "sanity");
142 _alloc_failure_degenerated++;
143 _degen_points[point]++;
144 }
145
146 void ShenandoahCollectorPolicy::record_degenerated_upgrade_to_full() {
147 _alloc_failure_degenerated_upgrade_to_full++;
148 }
149
150 void ShenandoahCollectorPolicy::record_success_concurrent() {
151 _success_concurrent_gcs++;
152 }
153
154 void ShenandoahCollectorPolicy::record_success_degenerated() {
155 _success_degenerated_gcs++;
156 }
157
158 void ShenandoahCollectorPolicy::record_success_full() {
159 _success_full_gcs++;
160 }
161
162 size_t ShenandoahCollectorPolicy::cycle_counter() const {
163 return _cycle_counter;
164 }
165
166 void ShenandoahCollectorPolicy::record_cycle_start() {
167 _cycle_counter++;
168 }
169
170 void ShenandoahCollectorPolicy::record_shutdown() {
171 _in_shutdown.set();
172 }
173
174 bool ShenandoahCollectorPolicy::is_at_shutdown() {
175 return _in_shutdown.is_set();
176 }
177
178 void ShenandoahCollectorPolicy::print_gc_stats(outputStream* out) const {
179 out->print_cr("Under allocation pressure, concurrent cycles may cancel, and either continue cycle");
180 out->print_cr("under stop-the-world pause or result in stop-the-world Full GC. Increase heap size,");
181 out->print_cr("tune GC heuristics, set more aggressive pacing delay, or lower allocation rate");
182 out->print_cr("to avoid Degenerated and Full GC cycles.");
183 out->cr();
184
185 out->print_cr(SIZE_FORMAT_W(5) " successful concurrent GCs", _success_concurrent_gcs);
186 out->print_cr(" " SIZE_FORMAT_W(5) " invoked explicitly", _explicit_concurrent);
187 out->print_cr(" " SIZE_FORMAT_W(5) " invoked implicitly", _implicit_concurrent);
188 out->cr();
189
190 out->print_cr(SIZE_FORMAT_W(5) " Degenerated GCs", _success_degenerated_gcs);
191 out->print_cr(" " SIZE_FORMAT_W(5) " caused by allocation failure", _alloc_failure_degenerated);
192 for (int c = 0; c < ShenandoahHeap::_DEGENERATED_LIMIT; c++) {
193 if (_degen_points[c] > 0) {
194 const char* desc = ShenandoahHeap::degen_point_to_string((ShenandoahHeap::ShenandoahDegenPoint)c);
195 out->print_cr(" " SIZE_FORMAT_W(5) " happened at %s", _degen_points[c], desc);
196 }
197 }
198 out->print_cr(" " SIZE_FORMAT_W(5) " upgraded to Full GC", _alloc_failure_degenerated_upgrade_to_full);
199 out->cr();
200
201 out->print_cr(SIZE_FORMAT_W(5) " Full GCs", _success_full_gcs + _alloc_failure_degenerated_upgrade_to_full);
202 out->print_cr(" " SIZE_FORMAT_W(5) " invoked explicitly", _explicit_full);
203 out->print_cr(" " SIZE_FORMAT_W(5) " invoked implicitly", _implicit_full);
204 out->print_cr(" " SIZE_FORMAT_W(5) " caused by allocation failure", _alloc_failure_full);
205 out->print_cr(" " SIZE_FORMAT_W(5) " upgraded from Degenerated GC", _alloc_failure_degenerated_upgrade_to_full);
206 }