1 /*
2 * Copyright (c) 2018, 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/g1/g1Arguments.hpp"
28 #include "gc/g1/g1CollectedHeap.inline.hpp"
29 #include "gc/g1/g1CollectorPolicy.hpp"
30 #include "gc/g1/g1HeapVerifier.hpp"
31 #include "gc/g1/heapRegion.hpp"
32 #include "gc/shared/gcArguments.inline.hpp"
33 #include "runtime/globals.hpp"
34 #include "runtime/globals_extension.hpp"
35 #include "runtime/vm_version.hpp"
36
37 size_t G1Arguments::conservative_max_heap_alignment() {
38 return HeapRegion::max_region_size();
39 }
40
41 void G1Arguments::initialize_verification_types() {
42 if (strlen(VerifyGCType) > 0) {
43 const char delimiter[] = " ,\n";
44 size_t length = strlen(VerifyGCType);
45 char* type_list = NEW_C_HEAP_ARRAY(char, length + 1, mtInternal);
46 strncpy(type_list, VerifyGCType, length + 1);
47 char* token = strtok(type_list, delimiter);
48 while (token != NULL) {
49 parse_verification_type(token);
50 token = strtok(NULL, delimiter);
51 }
52 FREE_C_HEAP_ARRAY(char, type_list);
53 }
54 }
55
56 void G1Arguments::parse_verification_type(const char* type) {
57 if (strcmp(type, "young-only") == 0) {
58 G1HeapVerifier::enable_verification_type(G1HeapVerifier::G1VerifyYoungOnly);
59 } else if (strcmp(type, "initial-mark") == 0) {
60 G1HeapVerifier::enable_verification_type(G1HeapVerifier::G1VerifyInitialMark);
61 } else if (strcmp(type, "mixed") == 0) {
62 G1HeapVerifier::enable_verification_type(G1HeapVerifier::G1VerifyMixed);
63 } else if (strcmp(type, "remark") == 0) {
64 G1HeapVerifier::enable_verification_type(G1HeapVerifier::G1VerifyRemark);
65 } else if (strcmp(type, "cleanup") == 0) {
66 G1HeapVerifier::enable_verification_type(G1HeapVerifier::G1VerifyCleanup);
67 } else if (strcmp(type, "full") == 0) {
68 G1HeapVerifier::enable_verification_type(G1HeapVerifier::G1VerifyFull);
69 } else {
70 log_warning(gc, verify)("VerifyGCType: '%s' is unknown. Available types are: "
71 "young-only, initial-mark, mixed, remark, cleanup and full", type);
72 }
73 }
74
75 void G1Arguments::initialize() {
76 GCArguments::initialize();
77 assert(UseG1GC, "Error");
78 FLAG_SET_DEFAULT(ParallelGCThreads, Abstract_VM_Version::parallel_worker_threads());
79 if (ParallelGCThreads == 0) {
80 assert(!FLAG_IS_DEFAULT(ParallelGCThreads), "The default value for ParallelGCThreads should not be 0.");
81 vm_exit_during_initialization("The flag -XX:+UseG1GC can not be combined with -XX:ParallelGCThreads=0", NULL);
82 }
83
84 #if INCLUDE_ALL_GCS
85 if (FLAG_IS_DEFAULT(G1ConcRefinementThreads)) {
86 FLAG_SET_ERGO(uint, G1ConcRefinementThreads, ParallelGCThreads);
87 }
88 #endif
89
90 // MarkStackSize will be set (if it hasn't been set by the user)
91 // when concurrent marking is initialized.
92 // Its value will be based upon the number of parallel marking threads.
93 // But we do set the maximum mark stack size here.
94 if (FLAG_IS_DEFAULT(MarkStackSizeMax)) {
95 FLAG_SET_DEFAULT(MarkStackSizeMax, 128 * TASKQUEUE_SIZE);
96 }
97
98 if (FLAG_IS_DEFAULT(GCTimeRatio) || GCTimeRatio == 0) {
99 // In G1, we want the default GC overhead goal to be higher than
100 // it is for PS, or the heap might be expanded too aggressively.
101 // We set it here to ~8%.
102 FLAG_SET_DEFAULT(GCTimeRatio, 12);
103 }
104
105 // Below, we might need to calculate the pause time interval based on
106 // the pause target. When we do so we are going to give G1 maximum
107 // flexibility and allow it to do pauses when it needs to. So, we'll
108 // arrange that the pause interval to be pause time target + 1 to
109 // ensure that a) the pause time target is maximized with respect to
110 // the pause interval and b) we maintain the invariant that pause
111 // time target < pause interval. If the user does not want this
112 // maximum flexibility, they will have to set the pause interval
113 // explicitly.
114
115 if (FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
116 // The default pause time target in G1 is 200ms
117 FLAG_SET_DEFAULT(MaxGCPauseMillis, 200);
118 }
119
120 // Then, if the interval parameter was not set, set it according to
121 // the pause time target (this will also deal with the case when the
122 // pause time target is the default value).
123 if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
124 FLAG_SET_DEFAULT(GCPauseIntervalMillis, MaxGCPauseMillis + 1);
125 }
126
127 log_trace(gc)("MarkStackSize: %uk MarkStackSizeMax: %uk", (unsigned int) (MarkStackSize / K), (uint) (MarkStackSizeMax / K));
128
129 #ifdef COMPILER2
130 // Enable loop strip mining to offer better pause time guarantees
131 if (FLAG_IS_DEFAULT(UseCountedLoopSafepoints)) {
132 FLAG_SET_DEFAULT(UseCountedLoopSafepoints, true);
133 if (FLAG_IS_DEFAULT(LoopStripMiningIter)) {
134 FLAG_SET_DEFAULT(LoopStripMiningIter, 1000);
135 }
136 }
137 #endif
138
139 initialize_verification_types();
140 }
141
142 CollectedHeap* G1Arguments::create_heap() {
143 return create_heap_with_policy<G1CollectedHeap, G1CollectorPolicy>();
144 }