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/java.hpp"
36 #include "utilities/defaultStream.hpp"
37 #include "utilities/powerOfTwo.hpp"
38
39 static const double MaxRamFractionForYoung = 0.8;
40
41 size_t ParallelArguments::conservative_max_heap_alignment() {
42 return compute_heap_alignment();
43 }
44
45 void ParallelArguments::initialize() {
46 GCArguments::initialize();
47 assert(UseParallelGC, "Error");
48
49 // If no heap maximum was requested explicitly, use some reasonable fraction
50 // of the physical memory, up to a maximum of 1GB.
51 FLAG_SET_DEFAULT(ParallelGCThreads,
52 WorkerPolicy::parallel_worker_threads());
53 if (ParallelGCThreads == 0) {
54 jio_fprintf(defaultStream::error_stream(),
55 "The Parallel GC can not be combined with -XX:ParallelGCThreads=0\n");
56 vm_exit(1);
57 }
58
59 if (UseAdaptiveSizePolicy) {
60 // We don't want to limit adaptive heap sizing's freedom to adjust the heap
61 // unless the user actually sets these flags.
62 if (FLAG_IS_DEFAULT(MinHeapFreeRatio)) {
63 FLAG_SET_DEFAULT(MinHeapFreeRatio, 0);
64 }
65 if (FLAG_IS_DEFAULT(MaxHeapFreeRatio)) {
66 FLAG_SET_DEFAULT(MaxHeapFreeRatio, 100);
67 }
68 }
69
70 // If InitialSurvivorRatio or MinSurvivorRatio were not specified, but the
71 // SurvivorRatio has been set, reset their default values to SurvivorRatio +
72 // 2. By doing this we make SurvivorRatio also work for Parallel Scavenger.
73 // See CR 6362902 for details.
74 if (!FLAG_IS_DEFAULT(SurvivorRatio)) {
75 if (FLAG_IS_DEFAULT(InitialSurvivorRatio)) {
76 FLAG_SET_DEFAULT(InitialSurvivorRatio, SurvivorRatio + 2);
77 }
78 if (FLAG_IS_DEFAULT(MinSurvivorRatio)) {
79 FLAG_SET_DEFAULT(MinSurvivorRatio, SurvivorRatio + 2);
80 }
81 }
82
83 // Par compact uses lower default values since they are treated as
84 // minimums. These are different defaults because of the different
85 // interpretation and are not ergonomically set.
86 if (FLAG_IS_DEFAULT(MarkSweepDeadRatio)) {
87 FLAG_SET_DEFAULT(MarkSweepDeadRatio, 1);
88 }
89 }
90
91 // The alignment used for boundary between young gen and old gen
92 static size_t default_gen_alignment() {
93 return 64 * K * HeapWordSize;
94 }
95
96 void ParallelArguments::initialize_alignments() {
97 SpaceAlignment = GenAlignment = default_gen_alignment();
98 HeapAlignment = compute_heap_alignment();
99 }
100
101 void ParallelArguments::initialize_heap_flags_and_sizes_one_pass() {
102 // Do basic sizing work
103 GenArguments::initialize_heap_flags_and_sizes();
104
105 // The survivor ratio's are calculated "raw", unlike the
106 // default gc, which adds 2 to the ratio value. We need to
107 // make sure the values are valid before using them.
108 if (MinSurvivorRatio < 3) {
109 FLAG_SET_ERGO(MinSurvivorRatio, 3);
110 }
111
112 if (InitialSurvivorRatio < 3) {
113 FLAG_SET_ERGO(InitialSurvivorRatio, 3);
114 }
115 }
116
117 void ParallelArguments::initialize_heap_flags_and_sizes() {
118 if (is_heterogeneous_heap()) {
119 initialize_heterogeneous();
120 }
121
122 initialize_heap_flags_and_sizes_one_pass();
123
124 const size_t max_page_sz = os::page_size_for_region_aligned(MaxHeapSize, 8);
125 const size_t min_pages = 4; // 1 for eden + 1 for each survivor + 1 for old
126 const size_t min_page_sz = os::page_size_for_region_aligned(MinHeapSize, min_pages);
127 const size_t page_sz = MIN2(max_page_sz, min_page_sz);
128
129 // Can a page size be something else than a power of two?
130 assert(is_power_of_2((intptr_t)page_sz), "must be a power of 2");
131 size_t new_alignment = align_up(page_sz, GenAlignment);
132 if (new_alignment != GenAlignment) {
133 GenAlignment = new_alignment;
134 SpaceAlignment = new_alignment;
135 // Redo everything from the start
136 initialize_heap_flags_and_sizes_one_pass();
137 }
138 }
139
140 // Check the available dram memory to limit NewSize and MaxNewSize before
141 // calling base class initialize_flags().
142 void ParallelArguments::initialize_heterogeneous() {
143 FormatBuffer<100> calc_str("");
144
145 julong phys_mem;
146 // If MaxRam is specified, we use that as maximum physical memory available.
147 if (FLAG_IS_DEFAULT(MaxRAM)) {
148 phys_mem = os::physical_memory();
149 calc_str.append("Physical_Memory");
150 } else {
151 phys_mem = (julong)MaxRAM;
152 calc_str.append("MaxRAM");
153 }
154
155 julong reasonable_max = phys_mem;
156
157 // If either MaxRAMFraction or MaxRAMPercentage is specified, we use them to calculate
158 // reasonable max size of young generation.
159 if (!FLAG_IS_DEFAULT(MaxRAMFraction)) {
160 reasonable_max = (julong)(phys_mem / MaxRAMFraction);
161 calc_str.append(" / MaxRAMFraction");
162 } else if (!FLAG_IS_DEFAULT(MaxRAMPercentage)) {
163 reasonable_max = (julong)((phys_mem * MaxRAMPercentage) / 100);
164 calc_str.append(" * MaxRAMPercentage / 100");
165 } else {
166 // We use our own fraction to calculate max size of young generation.
167 reasonable_max = phys_mem * MaxRamFractionForYoung;
168 calc_str.append(" * %0.2f", MaxRamFractionForYoung);
169 }
170 reasonable_max = align_up(reasonable_max, GenAlignment);
171
172 if (MaxNewSize > reasonable_max) {
173 if (FLAG_IS_CMDLINE(MaxNewSize)) {
174 log_warning(gc, ergo)("Setting MaxNewSize to " SIZE_FORMAT " based on dram available (calculation = align(%s))",
175 (size_t)reasonable_max, calc_str.buffer());
176 } else {
177 log_info(gc, ergo)("Setting MaxNewSize to " SIZE_FORMAT " based on dram available (calculation = align(%s)). "
178 "Dram usage can be lowered by setting MaxNewSize to a lower value", (size_t)reasonable_max, calc_str.buffer());
179 }
180 MaxNewSize = reasonable_max;
181 }
182 if (NewSize > reasonable_max) {
183 if (FLAG_IS_CMDLINE(NewSize)) {
184 log_warning(gc, ergo)("Setting NewSize to " SIZE_FORMAT " based on dram available (calculation = align(%s))",
185 (size_t)reasonable_max, calc_str.buffer());
186 }
187 NewSize = reasonable_max;
188 }
189 }
190
191 bool ParallelArguments::is_heterogeneous_heap() {
192 return AllocateOldGenAt != NULL;
193 }
194
195 size_t ParallelArguments::heap_reserved_size_bytes() {
196 if (!is_heterogeneous_heap() || !UseAdaptiveGCBoundary) {
197 return MaxHeapSize;
198 }
199
200 // Heterogeneous heap and adaptive size gc boundary
201
202 // This is the size that young gen can grow to, when UseAdaptiveGCBoundary is true.
203 size_t max_yg_size = MaxHeapSize - MinOldSize;
204 // This is the size that old gen can grow to, when UseAdaptiveGCBoundary is true.
205 size_t max_old_size = MaxHeapSize - MinNewSize;
206
207 return max_yg_size + max_old_size;
208 }
209
210 size_t ParallelArguments::heap_max_size_bytes() {
211 return MaxHeapSize;
212 }
213
214 CollectedHeap* ParallelArguments::create_heap() {
215 return new ParallelScavengeHeap();
216 }