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/fullGCForwarding.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 size_t ParallelArguments::conservative_max_heap_alignment() {
 41   return compute_heap_alignment();
 42 }
 43 
 44 void ParallelArguments::initialize() {
 45   GCArguments::initialize();
 46   assert(UseParallelGC, "Error");
 47 
 48   // If no heap maximum was requested explicitly, use some reasonable fraction
 49   // of the physical memory, up to a maximum of 1GB.
 50   FLAG_SET_DEFAULT(ParallelGCThreads,
 51                    WorkerPolicy::parallel_worker_threads());
 52   if (ParallelGCThreads == 0) {
 53     jio_fprintf(defaultStream::error_stream(),
 54         "The Parallel GC can not be combined with -XX:ParallelGCThreads=0\n");
 55     vm_exit(1);
 56   }
 57 
 58   if (UseAdaptiveSizePolicy) {
 59     // We don't want to limit adaptive heap sizing's freedom to adjust the heap
 60     // unless the user actually sets these flags.
 61     if (FLAG_IS_DEFAULT(MinHeapFreeRatio)) {
 62       FLAG_SET_DEFAULT(MinHeapFreeRatio, 0);
 63     }
 64     if (FLAG_IS_DEFAULT(MaxHeapFreeRatio)) {
 65       FLAG_SET_DEFAULT(MaxHeapFreeRatio, 100);
 66     }
 67   }
 68 
 69   if (InitialSurvivorRatio < MinSurvivorRatio) {
 70     if (FLAG_IS_CMDLINE(InitialSurvivorRatio)) {
 71       if (FLAG_IS_CMDLINE(MinSurvivorRatio)) {
 72         jio_fprintf(defaultStream::error_stream(),
 73           "Inconsistent MinSurvivorRatio vs InitialSurvivorRatio: %d vs %d\n", MinSurvivorRatio, InitialSurvivorRatio);
 74       }
 75       FLAG_SET_DEFAULT(MinSurvivorRatio, InitialSurvivorRatio);
 76     } else {
 77       FLAG_SET_DEFAULT(InitialSurvivorRatio, MinSurvivorRatio);
 78     }
 79   }
 80 
 81   // If InitialSurvivorRatio or MinSurvivorRatio were not specified, but the
 82   // SurvivorRatio has been set, reset their default values to SurvivorRatio +
 83   // 2.  By doing this we make SurvivorRatio also work for Parallel Scavenger.
 84   // See CR 6362902 for details.
 85   if (!FLAG_IS_DEFAULT(SurvivorRatio)) {
 86     if (FLAG_IS_DEFAULT(InitialSurvivorRatio)) {
 87        FLAG_SET_DEFAULT(InitialSurvivorRatio, SurvivorRatio + 2);
 88     }
 89     if (FLAG_IS_DEFAULT(MinSurvivorRatio)) {
 90       FLAG_SET_DEFAULT(MinSurvivorRatio, SurvivorRatio + 2);
 91     }
 92   }
 93 
 94   if (FLAG_IS_DEFAULT(ParallelRefProcEnabled) && ParallelGCThreads > 1) {
 95     FLAG_SET_DEFAULT(ParallelRefProcEnabled, true);
 96   }
 97 
 98   FullGCForwarding::initialize_flags(heap_reserved_size_bytes());
 99 }
100 
101 // The alignment used for boundary between young gen and old gen
102 static size_t default_gen_alignment() {
103   return 64 * K * HeapWordSize;
104 }
105 
106 void ParallelArguments::initialize_alignments() {
107   // Initialize card size before initializing alignments
108   CardTable::initialize_card_size();
109   SpaceAlignment = GenAlignment = default_gen_alignment();
110   HeapAlignment = compute_heap_alignment();
111 }
112 
113 void ParallelArguments::initialize_heap_flags_and_sizes_one_pass() {
114   // Do basic sizing work
115   GenArguments::initialize_heap_flags_and_sizes();
116 }
117 
118 void ParallelArguments::initialize_heap_flags_and_sizes() {
119   initialize_heap_flags_and_sizes_one_pass();
120 
121   const size_t min_pages = 4; // 1 for eden + 1 for each survivor + 1 for old
122   const size_t page_sz = os::page_size_for_region_aligned(MinHeapSize, min_pages);
123 
124   // Can a page size be something else than a power of two?
125   assert(is_power_of_2((intptr_t)page_sz), "must be a power of 2");
126   size_t new_alignment = align_up(page_sz, GenAlignment);
127   if (new_alignment != GenAlignment) {
128     GenAlignment = new_alignment;
129     SpaceAlignment = new_alignment;
130     // Redo everything from the start
131     initialize_heap_flags_and_sizes_one_pass();
132   }
133 }
134 
135 size_t ParallelArguments::heap_reserved_size_bytes() {
136   return MaxHeapSize;
137 }
138 
139 CollectedHeap* ParallelArguments::create_heap() {
140   return new ParallelScavengeHeap();
141 }