1 /*
2 * Copyright (c) 2018, 2020, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2017, Red Hat, Inc. and/or its affiliates.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "precompiled.hpp"
27 #include "gc/parallel/parallelArguments.hpp"
28 #include "gc/parallel/parallelScavengeHeap.hpp"
29 #include "gc/shared/adaptiveSizePolicy.hpp"
30 #include "gc/shared/gcArguments.hpp"
31 #include "gc/shared/genArguments.hpp"
32 #include "gc/shared/workerPolicy.hpp"
33 #include "logging/log.hpp"
34 #include "runtime/globals.hpp"
35 #include "runtime/globals_extension.hpp"
36 #include "runtime/java.hpp"
37 #include "utilities/defaultStream.hpp"
38 #include "utilities/powerOfTwo.hpp"
39
40 static const double MaxRamFractionForYoung = 0.8;
41
42 size_t ParallelArguments::conservative_max_heap_alignment() {
43 return compute_heap_alignment();
44 }
45
46 void ParallelArguments::initialize() {
47 GCArguments::initialize();
48 assert(UseParallelGC, "Error");
49
50 // If no heap maximum was requested explicitly, use some reasonable fraction
51 // of the physical memory, up to a maximum of 1GB.
52 FLAG_SET_DEFAULT(ParallelGCThreads,
53 WorkerPolicy::parallel_worker_threads());
54 if (ParallelGCThreads == 0) {
55 jio_fprintf(defaultStream::error_stream(),
56 "The Parallel GC can not be combined with -XX:ParallelGCThreads=0\n");
57 vm_exit(1);
58 }
59
60 if (UseAdaptiveSizePolicy) {
61 // We don't want to limit adaptive heap sizing's freedom to adjust the heap
62 // unless the user actually sets these flags.
63 if (FLAG_IS_DEFAULT(MinHeapFreeRatio)) {
64 FLAG_SET_DEFAULT(MinHeapFreeRatio, 0);
65 }
66 if (FLAG_IS_DEFAULT(MaxHeapFreeRatio)) {
67 FLAG_SET_DEFAULT(MaxHeapFreeRatio, 100);
68 }
69 }
70
71 // If InitialSurvivorRatio or MinSurvivorRatio were not specified, but the
72 // SurvivorRatio has been set, reset their default values to SurvivorRatio +
73 // 2. By doing this we make SurvivorRatio also work for Parallel Scavenger.
74 // See CR 6362902 for details.
75 if (!FLAG_IS_DEFAULT(SurvivorRatio)) {
76 if (FLAG_IS_DEFAULT(InitialSurvivorRatio)) {
77 FLAG_SET_DEFAULT(InitialSurvivorRatio, SurvivorRatio + 2);
78 }
79 if (FLAG_IS_DEFAULT(MinSurvivorRatio)) {
80 FLAG_SET_DEFAULT(MinSurvivorRatio, SurvivorRatio + 2);
81 }
82 }
83
84 // Par compact uses lower default values since they are treated as
85 // minimums. These are different defaults because of the different
86 // interpretation and are not ergonomically set.
87 if (FLAG_IS_DEFAULT(MarkSweepDeadRatio)) {
88 FLAG_SET_DEFAULT(MarkSweepDeadRatio, 1);
89 }
90 }
91
92 // The alignment used for boundary between young gen and old gen
93 static size_t default_gen_alignment() {
94 return 64 * K * HeapWordSize;
95 }
96
97 void ParallelArguments::initialize_alignments() {
98 SpaceAlignment = GenAlignment = default_gen_alignment();
99 HeapAlignment = compute_heap_alignment();
100 }
101
102 void ParallelArguments::initialize_heap_flags_and_sizes_one_pass() {
103 // Do basic sizing work
104 GenArguments::initialize_heap_flags_and_sizes();
105
106 // The survivor ratio's are calculated "raw", unlike the
107 // default gc, which adds 2 to the ratio value. We need to
108 // make sure the values are valid before using them.
109 if (MinSurvivorRatio < 3) {
110 FLAG_SET_ERGO(MinSurvivorRatio, 3);
111 }
112
113 if (InitialSurvivorRatio < 3) {
114 FLAG_SET_ERGO(InitialSurvivorRatio, 3);
115 }
116 }
117
118 void ParallelArguments::initialize_heap_flags_and_sizes() {
119 if (is_heterogeneous_heap()) {
120 initialize_heterogeneous();
121 }
122
123 initialize_heap_flags_and_sizes_one_pass();
124
125 const size_t max_page_sz = os::page_size_for_region_aligned(MaxHeapSize, 8);
126 const size_t min_pages = 4; // 1 for eden + 1 for each survivor + 1 for old
127 const size_t min_page_sz = os::page_size_for_region_aligned(MinHeapSize, min_pages);
128 const size_t page_sz = MIN2(max_page_sz, min_page_sz);
129
130 // Can a page size be something else than a power of two?
131 assert(is_power_of_2((intptr_t)page_sz), "must be a power of 2");
132 size_t new_alignment = align_up(page_sz, GenAlignment);
133 if (new_alignment != GenAlignment) {
134 GenAlignment = new_alignment;
135 SpaceAlignment = new_alignment;
136 // Redo everything from the start
137 initialize_heap_flags_and_sizes_one_pass();
138 }
139 }
140
141 // Check the available dram memory to limit NewSize and MaxNewSize before
142 // calling base class initialize_flags().
143 void ParallelArguments::initialize_heterogeneous() {
144 FormatBuffer<100> calc_str("");
145
146 julong phys_mem;
147 // If MaxRam is specified, we use that as maximum physical memory available.
148 if (FLAG_IS_DEFAULT(MaxRAM)) {
149 phys_mem = os::physical_memory();
150 calc_str.append("Physical_Memory");
151 } else {
152 phys_mem = (julong)MaxRAM;
153 calc_str.append("MaxRAM");
154 }
155
156 julong reasonable_max = phys_mem;
157
158 // If either MaxRAMFraction or MaxRAMPercentage is specified, we use them to calculate
159 // reasonable max size of young generation.
160 if (!FLAG_IS_DEFAULT(MaxRAMFraction)) {
161 reasonable_max = (julong)(phys_mem / MaxRAMFraction);
162 calc_str.append(" / MaxRAMFraction");
163 } else if (!FLAG_IS_DEFAULT(MaxRAMPercentage)) {
164 reasonable_max = (julong)((phys_mem * MaxRAMPercentage) / 100);
165 calc_str.append(" * MaxRAMPercentage / 100");
166 } else {
167 // We use our own fraction to calculate max size of young generation.
168 reasonable_max = phys_mem * MaxRamFractionForYoung;
169 calc_str.append(" * %0.2f", MaxRamFractionForYoung);
170 }
171 reasonable_max = align_up(reasonable_max, GenAlignment);
172
173 if (MaxNewSize > reasonable_max) {
174 if (FLAG_IS_CMDLINE(MaxNewSize)) {
175 log_warning(gc, ergo)("Setting MaxNewSize to " SIZE_FORMAT " based on dram available (calculation = align(%s))",
176 (size_t)reasonable_max, calc_str.buffer());
177 } else {
178 log_info(gc, ergo)("Setting MaxNewSize to " SIZE_FORMAT " based on dram available (calculation = align(%s)). "
179 "Dram usage can be lowered by setting MaxNewSize to a lower value", (size_t)reasonable_max, calc_str.buffer());
180 }
181 MaxNewSize = reasonable_max;
182 }
183 if (NewSize > reasonable_max) {
184 if (FLAG_IS_CMDLINE(NewSize)) {
185 log_warning(gc, ergo)("Setting NewSize to " SIZE_FORMAT " based on dram available (calculation = align(%s))",
186 (size_t)reasonable_max, calc_str.buffer());
187 }
188 NewSize = reasonable_max;
189 }
190 }
191
192 bool ParallelArguments::is_heterogeneous_heap() {
193 return AllocateOldGenAt != NULL;
194 }
195
196 size_t ParallelArguments::heap_reserved_size_bytes() {
197 if (!is_heterogeneous_heap() || !UseAdaptiveGCBoundary) {
198 return MaxHeapSize;
199 }
200
201 // Heterogeneous heap and adaptive size gc boundary
202
203 // This is the size that young gen can grow to, when UseAdaptiveGCBoundary is true.
204 size_t max_yg_size = MaxHeapSize - MinOldSize;
205 // This is the size that old gen can grow to, when UseAdaptiveGCBoundary is true.
206 size_t max_old_size = MaxHeapSize - MinNewSize;
207
208 return max_yg_size + max_old_size;
209 }
210
211 size_t ParallelArguments::heap_max_size_bytes() {
212 return MaxHeapSize;
213 }
214
215 CollectedHeap* ParallelArguments::create_heap() {
216 return new ParallelScavengeHeap();
217 }