1 /*
2 * Copyright (c) 2018, 2025, 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 "gc/parallel/parallelArguments.hpp"
27 #include "gc/parallel/parallelScavengeHeap.hpp"
28 #include "gc/shared/adaptiveSizePolicy.hpp"
29 #include "gc/shared/gcArguments.hpp"
30 #include "gc/shared/genArguments.hpp"
31 #include "gc/shared/workerPolicy.hpp"
32 #include "logging/log.hpp"
33 #include "runtime/globals.hpp"
34 #include "runtime/globals_extension.hpp"
35 #include "runtime/java.hpp"
36 #include "utilities/defaultStream.hpp"
37 #include "utilities/powerOfTwo.hpp"
38
39 size_t ParallelArguments::conservative_max_heap_alignment() {
40 return compute_heap_alignment();
41 }
42
43 void ParallelArguments::initialize() {
44 GCArguments::initialize();
45 assert(UseParallelGC, "Error");
46
47 // If no heap maximum was requested explicitly, use some reasonable fraction
48 // of the physical memory, up to a maximum of 1GB.
49 FLAG_SET_DEFAULT(ParallelGCThreads,
50 WorkerPolicy::parallel_worker_threads());
51 if (ParallelGCThreads == 0) {
52 jio_fprintf(defaultStream::error_stream(),
53 "The Parallel GC can not be combined with -XX:ParallelGCThreads=0\n");
54 vm_exit(1);
55 }
56
57 if (UseAdaptiveSizePolicy) {
58 // We don't want to limit adaptive heap sizing's freedom to adjust the heap
59 // unless the user actually sets these flags.
60 if (FLAG_IS_DEFAULT(MinHeapFreeRatio)) {
61 FLAG_SET_DEFAULT(MinHeapFreeRatio, 0);
62 }
63 if (FLAG_IS_DEFAULT(MaxHeapFreeRatio)) {
64 FLAG_SET_DEFAULT(MaxHeapFreeRatio, 100);
65 }
66 }
67
68 if (InitialSurvivorRatio < MinSurvivorRatio) {
69 if (FLAG_IS_CMDLINE(InitialSurvivorRatio)) {
70 if (FLAG_IS_CMDLINE(MinSurvivorRatio)) {
71 jio_fprintf(defaultStream::error_stream(),
72 "Inconsistent MinSurvivorRatio vs InitialSurvivorRatio: %zu vs %zu\n", MinSurvivorRatio, InitialSurvivorRatio);
73 }
74 FLAG_SET_DEFAULT(MinSurvivorRatio, InitialSurvivorRatio);
75 } else {
76 FLAG_SET_DEFAULT(InitialSurvivorRatio, MinSurvivorRatio);
77 }
78 }
79
80 // If InitialSurvivorRatio or MinSurvivorRatio were not specified, but the
81 // SurvivorRatio has been set, reset their default values to SurvivorRatio +
82 // 2. By doing this we make SurvivorRatio also work for Parallel Scavenger.
83 // See CR 6362902 for details.
84 if (!FLAG_IS_DEFAULT(SurvivorRatio)) {
85 if (FLAG_IS_DEFAULT(InitialSurvivorRatio)) {
86 FLAG_SET_DEFAULT(InitialSurvivorRatio, SurvivorRatio + 2);
87 }
88 if (FLAG_IS_DEFAULT(MinSurvivorRatio)) {
89 FLAG_SET_DEFAULT(MinSurvivorRatio, SurvivorRatio + 2);
90 }
91 }
92
93 if (FLAG_IS_DEFAULT(ParallelRefProcEnabled) && ParallelGCThreads > 1) {
94 FLAG_SET_DEFAULT(ParallelRefProcEnabled, true);
95 }
96 }
97
98 void ParallelArguments::initialize_alignments() {
99 // Initialize card size before initializing alignments
100 CardTable::initialize_card_size();
101 SpaceAlignment = ParallelScavengeHeap::default_space_alignment();
102 HeapAlignment = compute_heap_alignment();
103 }
104
105 void ParallelArguments::initialize_heap_flags_and_sizes_one_pass() {
106 // Do basic sizing work
107 GenArguments::initialize_heap_flags_and_sizes();
108 }
109
110 void ParallelArguments::initialize_heap_flags_and_sizes() {
111 initialize_heap_flags_and_sizes_one_pass();
112
113 if (!UseLargePages) {
114 ParallelScavengeHeap::set_desired_page_size(os::vm_page_size());
115 return;
116 }
117
118 // If using large-page, need to update SpaceAlignment so that spaces are page-size aligned.
119 const size_t min_pages = 4; // 1 for eden + 1 for each survivor + 1 for old
120 const size_t page_sz = os::page_size_for_region_aligned(MinHeapSize, min_pages);
121 ParallelScavengeHeap::set_desired_page_size(page_sz);
122
123 if (page_sz == os::vm_page_size()) {
124 log_warning(gc, heap)("MinHeapSize (%zu) must be large enough for 4 * page-size; Disabling UseLargePages for heap", MinHeapSize);
125 return;
126 }
127
128 // Space is largepage-aligned.
129 size_t new_alignment = page_sz;
130 if (new_alignment != SpaceAlignment) {
131 SpaceAlignment = new_alignment;
132 // Redo everything from the start
133 initialize_heap_flags_and_sizes_one_pass();
134 }
135 }
136
137 size_t ParallelArguments::heap_reserved_size_bytes() {
138 return MaxHeapSize;
139 }
140
141 CollectedHeap* ParallelArguments::create_heap() {
142 return new ParallelScavengeHeap();
143 }