1 /*
2 * Copyright (c) 2015, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "gc/cms/jvmFlagConstraintsCMS.hpp"
27 #include "gc/cms/concurrentMarkSweepGeneration.inline.hpp"
28 #include "gc/shared/cardTableRS.hpp"
29 #include "gc/shared/collectedHeap.hpp"
30 #include "gc/shared/genCollectedHeap.hpp"
31 #include "gc/shared/jvmFlagConstraintsGC.hpp"
32 #include "memory/universe.hpp"
33 #include "runtime/globals_extension.hpp"
34 #include "utilities/globalDefinitions.hpp"
35
36 static JVMFlag::Error ParallelGCThreadsAndCMSWorkQueueDrainThreshold(uint threads, uintx threshold, bool verbose) {
37 // CMSWorkQueueDrainThreshold is verified to be less than max_juint
38 if (UseConcMarkSweepGC && (threads > (uint)(max_jint / (uint)threshold))) {
39 JVMFlag::printError(verbose,
40 "ParallelGCThreads (" UINT32_FORMAT ") or CMSWorkQueueDrainThreshold ("
41 UINTX_FORMAT ") is too large\n",
42 threads, threshold);
43 return JVMFlag::VIOLATES_CONSTRAINT;
44 }
45 return JVMFlag::SUCCESS;
46 }
47
48 JVMFlag::Error ParallelGCThreadsConstraintFuncCMS(uint value, bool verbose) {
49 // To avoid overflow at ParScanClosure::do_oop_work.
50 if (UseConcMarkSweepGC && (value > (max_jint / 10))) {
51 JVMFlag::printError(verbose,
52 "ParallelGCThreads (" UINT32_FORMAT ") must be "
53 "less than or equal to " UINT32_FORMAT " for CMS GC\n",
54 value, (max_jint / 10));
55 return JVMFlag::VIOLATES_CONSTRAINT;
56 }
57 return ParallelGCThreadsAndCMSWorkQueueDrainThreshold(value, CMSWorkQueueDrainThreshold, verbose);
58 }
59 JVMFlag::Error ParGCStridesPerThreadConstraintFunc(uintx value, bool verbose) {
60 if (UseConcMarkSweepGC && (value > ((uintx)max_jint / (uintx)ParallelGCThreads))) {
61 JVMFlag::printError(verbose,
62 "ParGCStridesPerThread (" UINTX_FORMAT ") must be "
63 "less than or equal to ergonomic maximum (" UINTX_FORMAT ")\n",
64 value, ((uintx)max_jint / (uintx)ParallelGCThreads));
65 return JVMFlag::VIOLATES_CONSTRAINT;
66 }
67 return JVMFlag::SUCCESS;
68 }
69
70 JVMFlag::Error ParGCCardsPerStrideChunkConstraintFunc(intx value, bool verbose) {
71 if (UseConcMarkSweepGC) {
72 // ParGCCardsPerStrideChunk should be compared with card table size.
73 size_t heap_size = Universe::heap()->reserved_region().word_size();
74 CardTableRS* ct = GenCollectedHeap::heap()->rem_set();
75 size_t card_table_size = ct->cards_required(heap_size) - 1; // Valid card table size
76
77 if ((size_t)value > card_table_size) {
78 JVMFlag::printError(verbose,
79 "ParGCCardsPerStrideChunk (" INTX_FORMAT ") is too large for the heap size and "
80 "must be less than or equal to card table size (" SIZE_FORMAT ")\n",
81 value, card_table_size);
82 return JVMFlag::VIOLATES_CONSTRAINT;
83 }
84
85 // ParGCCardsPerStrideChunk is used with n_strides(ParallelGCThreads*ParGCStridesPerThread)
86 // from CardTableRS::process_stride(). Note that ParGCStridesPerThread is already checked
87 // not to make an overflow with ParallelGCThreads from its constraint function.
88 uintx n_strides = ParallelGCThreads * ParGCStridesPerThread;
89 uintx ergo_max = max_uintx / n_strides;
90 if ((uintx)value > ergo_max) {
91 JVMFlag::printError(verbose,
92 "ParGCCardsPerStrideChunk (" INTX_FORMAT ") must be "
93 "less than or equal to ergonomic maximum (" UINTX_FORMAT ")\n",
94 value, ergo_max);
95 return JVMFlag::VIOLATES_CONSTRAINT;
96 }
97 }
98 return JVMFlag::SUCCESS;
99 }
100
101 JVMFlag::Error CMSOldPLABMinConstraintFunc(size_t value, bool verbose) {
102 JVMFlag::Error status = JVMFlag::SUCCESS;
103
104 if (UseConcMarkSweepGC) {
105 if (value > CMSOldPLABMax) {
106 JVMFlag::printError(verbose,
107 "CMSOldPLABMin (" SIZE_FORMAT ") must be "
108 "less than or equal to CMSOldPLABMax (" SIZE_FORMAT ")\n",
109 value, CMSOldPLABMax);
110 return JVMFlag::VIOLATES_CONSTRAINT;
111 }
112 status = MaxPLABSizeBounds("CMSOldPLABMin", value, verbose);
113 }
114 return status;
115 }
116
117 JVMFlag::Error CMSOldPLABMaxConstraintFunc(size_t value, bool verbose) {
118 JVMFlag::Error status = JVMFlag::SUCCESS;
119
120 if (UseConcMarkSweepGC) {
121 status = MaxPLABSizeBounds("CMSOldPLABMax", value, verbose);
122 }
123 return status;
124 }
125
126 static JVMFlag::Error CMSReservedAreaConstraintFunc(const char* name, size_t value, bool verbose) {
127 if (UseConcMarkSweepGC) {
128 ConcurrentMarkSweepGeneration* cms = CMSHeap::heap()->old_gen();
129 const size_t ergo_max = cms->cmsSpace()->max_flag_size_for_task_size();
130 if (value > ergo_max) {
131 JVMFlag::printError(verbose,
132 "%s (" SIZE_FORMAT ") must be "
133 "less than or equal to ergonomic maximum (" SIZE_FORMAT ") "
134 "which is based on the maximum size of the old generation of the Java heap\n",
135 name, value, ergo_max);
136 return JVMFlag::VIOLATES_CONSTRAINT;
137 }
138 }
139 return JVMFlag::SUCCESS;
140 }
141
142 JVMFlag::Error CMSRescanMultipleConstraintFunc(size_t value, bool verbose) {
143 JVMFlag::Error status = CMSReservedAreaConstraintFunc("CMSRescanMultiple", value, verbose);
144
145 if (status == JVMFlag::SUCCESS && UseConcMarkSweepGC) {
146 // CMSParRemarkTask::do_dirty_card_rescan_tasks requires CompactibleFreeListSpace::rescan_task_size()
147 // to be aligned to CardTable::card_size * BitsPerWord.
148 // Note that rescan_task_size() will be aligned if CMSRescanMultiple is a multiple of 'HeapWordSize'
149 // because rescan_task_size() is CardTable::card_size / HeapWordSize * BitsPerWord.
150 if (value % HeapWordSize != 0) {
151 JVMFlag::printError(verbose,
152 "CMSRescanMultiple (" SIZE_FORMAT ") must be "
153 "a multiple of " INT32_FORMAT "\n",
154 value, HeapWordSize);
155 status = JVMFlag::VIOLATES_CONSTRAINT;
156 }
157 }
158 return status;
159 }
160
161 JVMFlag::Error CMSConcMarkMultipleConstraintFunc(size_t value, bool verbose) {
162 return CMSReservedAreaConstraintFunc("CMSConcMarkMultiple", value, verbose);
163 }
164
165 JVMFlag::Error CMSPrecleanDenominatorConstraintFunc(uintx value, bool verbose) {
166 if (UseConcMarkSweepGC && (value <= CMSPrecleanNumerator)) {
167 JVMFlag::printError(verbose,
168 "CMSPrecleanDenominator (" UINTX_FORMAT ") must be "
169 "strickly greater than CMSPrecleanNumerator (" UINTX_FORMAT ")\n",
170 value, CMSPrecleanNumerator);
171 return JVMFlag::VIOLATES_CONSTRAINT;
172 }
173 return JVMFlag::SUCCESS;
174 }
175
176 JVMFlag::Error CMSPrecleanNumeratorConstraintFunc(uintx value, bool verbose) {
177 if (UseConcMarkSweepGC && (value >= CMSPrecleanDenominator)) {
178 JVMFlag::printError(verbose,
179 "CMSPrecleanNumerator (" UINTX_FORMAT ") must be "
180 "less than CMSPrecleanDenominator (" UINTX_FORMAT ")\n",
181 value, CMSPrecleanDenominator);
182 return JVMFlag::VIOLATES_CONSTRAINT;
183 }
184 return JVMFlag::SUCCESS;
185 }
186
187 JVMFlag::Error CMSSamplingGrainConstraintFunc(uintx value, bool verbose) {
188 if (UseConcMarkSweepGC) {
189 size_t max_capacity = CMSHeap::heap()->young_gen()->max_capacity();
190 if (value > max_uintx - max_capacity) {
191 JVMFlag::printError(verbose,
192 "CMSSamplingGrain (" UINTX_FORMAT ") must be "
193 "less than or equal to ergonomic maximum (" SIZE_FORMAT ")\n",
194 value, max_uintx - max_capacity);
195 return JVMFlag::VIOLATES_CONSTRAINT;
196 }
197 }
198 return JVMFlag::SUCCESS;
199 }
200
201 JVMFlag::Error CMSWorkQueueDrainThresholdConstraintFunc(uintx value, bool verbose) {
202 if (UseConcMarkSweepGC) {
203 return ParallelGCThreadsAndCMSWorkQueueDrainThreshold(ParallelGCThreads, value, verbose);
204 }
205 return JVMFlag::SUCCESS;
206 }
207
208 JVMFlag::Error CMSBitMapYieldQuantumConstraintFunc(size_t value, bool verbose) {
209 // Skip for current default value.
210 if (UseConcMarkSweepGC && FLAG_IS_CMDLINE(CMSBitMapYieldQuantum)) {
211 // CMSBitMapYieldQuantum should be compared with mark bitmap size.
212 ConcurrentMarkSweepGeneration* cms = CMSHeap::heap()->old_gen();
213 size_t bitmap_size = cms->collector()->markBitMap()->sizeInWords();
214
215 if (value > bitmap_size) {
216 JVMFlag::printError(verbose,
217 "CMSBitMapYieldQuantum (" SIZE_FORMAT ") must "
218 "be less than or equal to bitmap size (" SIZE_FORMAT ") "
219 "whose size corresponds to the size of old generation of the Java heap\n",
220 value, bitmap_size);
221 return JVMFlag::VIOLATES_CONSTRAINT;
222 }
223 }
224 return JVMFlag::SUCCESS;
225 }
226
227 JVMFlag::Error OldPLABSizeConstraintFuncCMS(size_t value, bool verbose) {
228 if (value == 0) {
229 JVMFlag::printError(verbose,
230 "OldPLABSize (" SIZE_FORMAT ") must be greater than 0",
231 value);
232 return JVMFlag::VIOLATES_CONSTRAINT;
233 }
234 // For CMS, OldPLABSize is the number of free blocks of a given size that are used when
235 // replenishing the local per-worker free list caches.
236 // For more details, please refer to Arguments::set_cms_and_parnew_gc_flags().
237 return MaxPLABSizeBounds("OldPLABSize", value, verbose);
238 }