1 /*
2 * Copyright (c) 1997, 2021, 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 #ifndef SHARE_GC_SHARED_GC_GLOBALS_HPP
26 #define SHARE_GC_SHARED_GC_GLOBALS_HPP
27
28 #include "runtime/globals_shared.hpp"
29 #include "utilities/macros.hpp"
30 #if INCLUDE_EPSILONGC
31 #include "gc/epsilon/epsilon_globals.hpp"
32 #endif
33 #if INCLUDE_G1GC
34 #include "gc/g1/g1_globals.hpp"
35 #endif
36 #if INCLUDE_PARALLELGC
37 #include "gc/parallel/parallel_globals.hpp"
38 #endif
39 #if INCLUDE_SERIALGC
40 #include "gc/serial/serial_globals.hpp"
41 #endif
42 #if INCLUDE_SHENANDOAHGC
43 #include "gc/shenandoah/shenandoah_globals.hpp"
44 #endif
45 #if INCLUDE_ZGC
46 #include "gc/z/z_globals.hpp"
47 #endif
48
49 #define GC_FLAGS(develop, \
50 develop_pd, \
51 product, \
52 product_pd, \
53 notproduct, \
54 range, \
55 constraint) \
56 \
57 EPSILONGC_ONLY(GC_EPSILON_FLAGS( \
58 develop, \
59 develop_pd, \
60 product, \
61 product_pd, \
62 notproduct, \
63 range, \
64 constraint)) \
65 \
66 G1GC_ONLY(GC_G1_FLAGS( \
67 develop, \
68 develop_pd, \
69 product, \
70 product_pd, \
71 notproduct, \
72 range, \
73 constraint)) \
74 \
75 PARALLELGC_ONLY(GC_PARALLEL_FLAGS( \
76 develop, \
77 develop_pd, \
78 product, \
79 product_pd, \
80 notproduct, \
81 range, \
82 constraint)) \
83 \
84 SERIALGC_ONLY(GC_SERIAL_FLAGS( \
85 develop, \
86 develop_pd, \
87 product, \
88 product_pd, \
89 notproduct, \
90 range, \
91 constraint)) \
92 \
93 SHENANDOAHGC_ONLY(GC_SHENANDOAH_FLAGS( \
94 develop, \
95 develop_pd, \
96 product, \
97 product_pd, \
98 notproduct, \
99 range, \
100 constraint)) \
101 \
102 ZGC_ONLY(GC_Z_FLAGS( \
103 develop, \
104 develop_pd, \
105 product, \
106 product_pd, \
107 notproduct, \
108 range, \
109 constraint)) \
110 \
111 /* gc */ \
112 \
113 product(bool, UseSerialGC, false, \
114 "Use the Serial garbage collector") \
115 \
116 product(bool, UseG1GC, false, \
117 "Use the Garbage-First garbage collector") \
118 \
119 product(bool, UseParallelGC, false, \
120 "Use the Parallel garbage collector.") \
121 \
122 product(bool, UseEpsilonGC, false, EXPERIMENTAL, \
123 "Use the Epsilon (no-op) garbage collector") \
124 \
125 product(bool, UseZGC, false, \
126 "Use the Z garbage collector") \
127 \
128 product(bool, UseShenandoahGC, false, \
129 "Use the Shenandoah garbage collector") \
130 \
131 product(uint, ParallelGCThreads, 0, \
132 "Number of parallel threads parallel gc will use") \
133 constraint(ParallelGCThreadsConstraintFunc,AfterErgo) \
134 \
135 product(bool, UseDynamicNumberOfGCThreads, true, \
136 "Dynamically choose the number of threads up to a maximum of " \
137 "ParallelGCThreads parallel collectors will use for garbage " \
138 "collection work") \
139 \
140 product(bool, InjectGCWorkerCreationFailure, false, DIAGNOSTIC, \
141 "Inject thread creation failures for " \
142 "UseDynamicNumberOfGCThreads") \
143 \
144 product(size_t, HeapSizePerGCThread, ScaleForWordSize(32*M), \
145 "Size of heap (bytes) per GC thread used in calculating the " \
146 "number of GC threads") \
147 constraint(VMPageSizeConstraintFunc, AtParse) \
148 \
149 product(uint, ConcGCThreads, 0, \
150 "Number of threads concurrent gc will use") \
151 constraint(ConcGCThreadsConstraintFunc,AfterErgo) \
152 \
153 product(bool, AlwaysTenure, false, \
154 "Always tenure objects in eden (ParallelGC only)") \
155 \
156 product(bool, NeverTenure, false, \
157 "Never tenure objects in eden, may tenure on overflow " \
158 "(ParallelGC only)") \
159 \
160 product(bool, ScavengeBeforeFullGC, true, \
161 "Scavenge youngest generation before each full GC.") \
162 \
163 product(bool, ExplicitGCInvokesConcurrent, false, \
164 "A System.gc() request invokes a concurrent collection; " \
165 "(effective only when using concurrent collectors)") \
166 \
167 product(uintx, GCLockerEdenExpansionPercent, 5, \
168 "How much the GC can expand the eden by while the GC locker " \
169 "is active (as a percentage)") \
170 range(0, 100) \
171 \
172 product(uintx, GCLockerRetryAllocationCount, 2, DIAGNOSTIC, \
173 "Number of times to retry allocations when " \
174 "blocked by the GC locker") \
175 range(0, max_uintx) \
176 \
177 product(uintx, ParallelGCBufferWastePct, 10, \
178 "Wasted fraction of parallel allocation buffer") \
179 range(0, 100) \
180 \
181 product(uintx, TargetPLABWastePct, 10, \
182 "Target wasted space in last buffer as percent of overall " \
183 "allocation") \
184 range(1, 100) \
185 \
186 product(uintx, PLABWeight, 75, \
187 "Percentage (0-100) used to weight the current sample when " \
188 "computing exponentially decaying average for ResizePLAB") \
189 range(0, 100) \
190 \
191 product(bool, ResizePLAB, true, \
192 "Dynamically resize (survivor space) promotion LAB's") \
193 \
194 product(int, ParGCArrayScanChunk, 50, \
195 "Scan a subset of object array and push remainder, if array is " \
196 "bigger than this") \
197 range(1, max_jint/3) \
198 \
199 \
200 product(bool, AlwaysPreTouch, false, \
201 "Force all freshly committed pages to be pre-touched") \
202 \
203 product_pd(size_t, PreTouchParallelChunkSize, \
204 "Per-thread chunk size for parallel memory pre-touch.") \
205 range(4*K, SIZE_MAX / 2) \
206 \
207 /* where does the range max value of (max_jint - 1) come from? */ \
208 product(size_t, MarkStackSizeMax, NOT_LP64(4*M) LP64_ONLY(512*M), \
209 "Maximum size of marking stack") \
210 range(1, (max_jint - 1)) \
211 \
212 product(size_t, MarkStackSize, NOT_LP64(32*K) LP64_ONLY(4*M), \
213 "Size of marking stack") \
214 constraint(MarkStackSizeConstraintFunc,AfterErgo) \
215 range(1, (max_jint - 1)) \
216 \
217 product(intx, RefDiscoveryPolicy, 0, \
218 "Select type of reference discovery policy: " \
219 "reference-based(0) or referent-based(1)") \
220 range(ReferenceProcessor::DiscoveryPolicyMin, \
221 ReferenceProcessor::DiscoveryPolicyMax) \
222 \
223 product(bool, ParallelRefProcEnabled, false, \
224 "Enable parallel reference processing whenever possible") \
225 \
226 product(bool, ParallelRefProcBalancingEnabled, true, \
227 "Enable balancing of reference processing queues") \
228 \
229 product(size_t, ReferencesPerThread, 1000, EXPERIMENTAL, \
230 "Ergonomically start one thread for this amount of " \
231 "references for reference processing if " \
232 "ParallelRefProcEnabled is true. Specify 0 to disable and " \
233 "use all threads.") \
234 \
235 product(uintx, InitiatingHeapOccupancyPercent, 45, \
236 "The percent occupancy (IHOP) of the current old generation " \
237 "capacity above which a concurrent mark cycle will be initiated " \
238 "Its value may change over time if adaptive IHOP is enabled, " \
239 "otherwise the value remains constant. " \
240 "In the latter case a value of 0 will result as frequent as " \
241 "possible concurrent marking cycles. A value of 100 disables " \
242 "concurrent marking. " \
243 "Fragmentation waste in the old generation is not considered " \
244 "free space in this calculation. (G1 collector only)") \
245 range(0, 100) \
246 \
247 notproduct(bool, ScavengeALot, false, \
248 "Force scavenge at every Nth exit from the runtime system " \
249 "(N=ScavengeALotInterval)") \
250 \
251 develop(bool, FullGCALot, false, \
252 "Force full gc at every Nth exit from the runtime system " \
253 "(N=FullGCALotInterval)") \
254 \
255 notproduct(bool, GCALotAtAllSafepoints, false, \
256 "Enforce ScavengeALot/GCALot at all potential safepoints") \
257 \
258 notproduct(bool, PromotionFailureALot, false, \
259 "Use promotion failure handling on every youngest generation " \
260 "collection") \
261 \
262 develop(uintx, PromotionFailureALotCount, 1000, \
263 "Number of promotion failures occurring at PLAB promotion " \
264 "attempts at young collectors") \
265 \
266 develop(uintx, PromotionFailureALotInterval, 5, \
267 "Total collections between promotion failures a lot") \
268 \
269 product(uintx, WorkStealingSleepMillis, 1, EXPERIMENTAL, \
270 "Sleep time when sleep is used for yields") \
271 \
272 product(uintx, WorkStealingYieldsBeforeSleep, 5000, EXPERIMENTAL, \
273 "Number of yields before a sleep is done during work stealing") \
274 \
275 product(uintx, WorkStealingHardSpins, 4096, EXPERIMENTAL, \
276 "Number of iterations in a spin loop between checks on " \
277 "time out of hard spin") \
278 \
279 product(uintx, WorkStealingSpinToYieldRatio, 10, EXPERIMENTAL, \
280 "Ratio of hard spins to calls to yield") \
281 \
282 develop(uintx, ObjArrayMarkingStride, 2048, \
283 "Number of object array elements to push onto the marking stack " \
284 "before pushing a continuation entry") \
285 \
286 develop(bool, MetadataAllocationFailALot, false, \
287 "Fail metadata allocations at intervals controlled by " \
288 "MetadataAllocationFailALotInterval") \
289 \
290 develop(uintx, MetadataAllocationFailALotInterval, 1000, \
291 "Metadata allocation failure a lot interval") \
292 \
293 product_pd(bool, NeverActAsServerClassMachine, \
294 "Never act like a server-class machine") \
295 \
296 product(bool, AlwaysActAsServerClassMachine, false, \
297 "Always act like a server-class machine") \
298 \
299 product_pd(uint64_t, MaxRAM, \
300 "Real memory size (in bytes) used to set maximum heap size") \
301 range(0, 0XFFFFFFFFFFFFFFFF) \
302 \
303 product(bool, AggressiveHeap, false, \
304 "Optimize heap options for long-running memory intensive apps") \
305 \
306 product(size_t, ErgoHeapSizeLimit, 0, \
307 "Maximum ergonomically set heap size (in bytes); zero means use " \
308 "MaxRAM * MaxRAMPercentage / 100") \
309 range(0, max_uintx) \
310 \
311 product(uintx, MaxRAMFraction, 4, \
312 "Maximum fraction (1/n) of real memory used for maximum heap " \
313 "size. " \
314 "Deprecated, use MaxRAMPercentage instead") \
315 range(1, max_uintx) \
316 \
317 product(uintx, MinRAMFraction, 2, \
318 "Minimum fraction (1/n) of real memory used for maximum heap " \
319 "size on systems with small physical memory size. " \
320 "Deprecated, use MinRAMPercentage instead") \
321 range(1, max_uintx) \
322 \
323 product(uintx, InitialRAMFraction, 64, \
324 "Fraction (1/n) of real memory used for initial heap size. " \
325 "Deprecated, use InitialRAMPercentage instead") \
326 range(1, max_uintx) \
327 \
328 product(double, MaxRAMPercentage, 25.0, \
329 "Maximum percentage of real memory used for maximum heap size") \
330 range(0.0, 100.0) \
331 \
332 product(double, MinRAMPercentage, 50.0, \
333 "Minimum percentage of real memory used for maximum heap" \
334 "size on systems with small physical memory size") \
335 range(0.0, 100.0) \
336 \
337 product(double, InitialRAMPercentage, 1.5625, \
338 "Percentage of real memory used for initial heap size") \
339 range(0.0, 100.0) \
340 \
341 product(int, ActiveProcessorCount, -1, \
342 "Specify the CPU count the VM should use and report as active") \
343 \
344 develop(uintx, MaxVirtMemFraction, 2, \
345 "Maximum fraction (1/n) of virtual memory used for ergonomically "\
346 "determining maximum heap size") \
347 range(1, max_uintx) \
348 \
349 product(bool, UseAdaptiveSizePolicy, true, \
350 "Use adaptive generation sizing policies") \
351 \
352 product(bool, UsePSAdaptiveSurvivorSizePolicy, true, \
353 "Use adaptive survivor sizing policies") \
354 \
355 product(bool, UseAdaptiveGenerationSizePolicyAtMinorCollection, true, \
356 "Use adaptive young-old sizing policies at minor collections") \
357 \
358 product(bool, UseAdaptiveGenerationSizePolicyAtMajorCollection, true, \
359 "Use adaptive young-old sizing policies at major collections") \
360 \
361 product(bool, UseAdaptiveSizePolicyWithSystemGC, false, \
362 "Include statistics from System.gc() for adaptive size policy") \
363 \
364 develop(intx, PSAdaptiveSizePolicyResizeVirtualSpaceAlot, -1, \
365 "Resize the virtual spaces of the young or old generations") \
366 range(-1, 1) \
367 \
368 product(uintx, AdaptiveSizeThroughPutPolicy, 0, \
369 "Policy for changing generation size for throughput goals") \
370 range(0, 1) \
371 \
372 product(uintx, AdaptiveSizePolicyInitializingSteps, 20, \
373 "Number of steps where heuristics is used before data is used") \
374 range(0, max_uintx) \
375 \
376 develop(uintx, AdaptiveSizePolicyReadyThreshold, 5, \
377 "Number of collections before the adaptive sizing is started") \
378 \
379 product(uintx, AdaptiveSizePolicyOutputInterval, 0, \
380 "Collection interval for printing information; zero means never") \
381 range(0, max_uintx) \
382 \
383 product(bool, UseAdaptiveSizePolicyFootprintGoal, true, \
384 "Use adaptive minimum footprint as a goal") \
385 \
386 product(uintx, AdaptiveSizePolicyWeight, 10, \
387 "Weight given to exponential resizing, between 0 and 100") \
388 range(0, 100) \
389 \
390 product(uintx, AdaptiveTimeWeight, 25, \
391 "Weight given to time in adaptive policy, between 0 and 100") \
392 range(0, 100) \
393 \
394 product(uintx, PausePadding, 1, \
395 "How much buffer to keep for pause time") \
396 range(0, max_juint) \
397 \
398 product(uintx, PromotedPadding, 3, \
399 "How much buffer to keep for promotion failure") \
400 range(0, max_juint) \
401 \
402 product(uintx, SurvivorPadding, 3, \
403 "How much buffer to keep for survivor overflow") \
404 range(0, max_juint) \
405 \
406 product(uintx, ThresholdTolerance, 10, \
407 "Allowed collection cost difference between generations") \
408 range(0, 100) \
409 \
410 product(uintx, AdaptiveSizePolicyCollectionCostMargin, 50, \
411 "If collection costs are within margin, reduce both by full " \
412 "delta") \
413 range(0, 100) \
414 \
415 product(uintx, YoungGenerationSizeIncrement, 20, \
416 "Adaptive size percentage change in young generation") \
417 range(0, 100) \
418 \
419 product(uintx, YoungGenerationSizeSupplement, 80, \
420 "Supplement to YoungedGenerationSizeIncrement used at startup") \
421 range(0, 100) \
422 \
423 product(uintx, YoungGenerationSizeSupplementDecay, 8, \
424 "Decay factor to YoungedGenerationSizeSupplement") \
425 range(1, max_uintx) \
426 \
427 product(uintx, TenuredGenerationSizeIncrement, 20, \
428 "Adaptive size percentage change in tenured generation") \
429 range(0, 100) \
430 \
431 product(uintx, TenuredGenerationSizeSupplement, 80, \
432 "Supplement to TenuredGenerationSizeIncrement used at startup") \
433 range(0, 100) \
434 \
435 product(uintx, TenuredGenerationSizeSupplementDecay, 2, \
436 "Decay factor to TenuredGenerationSizeIncrement") \
437 range(1, max_uintx) \
438 \
439 product(uintx, MaxGCPauseMillis, max_uintx - 1, \
440 "Adaptive size policy maximum GC pause time goal in millisecond, "\
441 "or (G1 Only) the maximum GC time per MMU time slice") \
442 range(1, max_uintx - 1) \
443 constraint(MaxGCPauseMillisConstraintFunc,AfterErgo) \
444 \
445 product(uintx, GCPauseIntervalMillis, 0, \
446 "Time slice for MMU specification") \
447 constraint(GCPauseIntervalMillisConstraintFunc,AfterErgo) \
448 \
449 product(uintx, MaxGCMinorPauseMillis, max_uintx, \
450 "Adaptive size policy maximum GC minor pause time goal " \
451 "in millisecond") \
452 range(0, max_uintx) \
453 \
454 product(uintx, GCTimeRatio, 99, \
455 "Adaptive size policy application time to GC time ratio") \
456 range(0, max_juint) \
457 \
458 product(uintx, AdaptiveSizeDecrementScaleFactor, 4, \
459 "Adaptive size scale down factor for shrinking") \
460 range(1, max_uintx) \
461 \
462 product(bool, UseAdaptiveSizeDecayMajorGCCost, true, \
463 "Adaptive size decays the major cost for long major intervals") \
464 \
465 product(uintx, AdaptiveSizeMajorGCDecayTimeScale, 10, \
466 "Time scale over which major costs decay") \
467 range(0, max_uintx) \
468 \
469 product(uintx, MinSurvivorRatio, 3, \
470 "Minimum ratio of young generation/survivor space size") \
471 range(3, max_uintx) \
472 \
473 product(uintx, InitialSurvivorRatio, 8, \
474 "Initial ratio of young generation/survivor space size") \
475 range(0, max_uintx) \
476 \
477 product(size_t, BaseFootPrintEstimate, 256*M, \
478 "Estimate of footprint other than Java Heap") \
479 range(0, max_uintx) \
480 \
481 product(bool, UseGCOverheadLimit, true, \
482 "Use policy to limit of proportion of time spent in GC " \
483 "before an OutOfMemory error is thrown") \
484 \
485 product(uintx, GCTimeLimit, 98, \
486 "Limit of the proportion of time spent in GC before " \
487 "an OutOfMemoryError is thrown (used with GCHeapFreeLimit)") \
488 range(0, 100) \
489 \
490 product(uintx, GCHeapFreeLimit, 2, \
491 "Minimum percentage of free space after a full GC before an " \
492 "OutOfMemoryError is thrown (used with GCTimeLimit)") \
493 range(0, 100) \
494 \
495 develop(uintx, GCOverheadLimitThreshold, 5, \
496 "Number of consecutive collections before gc time limit fires") \
497 range(1, max_uintx) \
498 \
499 product(intx, PrefetchCopyIntervalInBytes, -1, \
500 "How far ahead to prefetch destination area (<= 0 means off)") \
501 range(-1, max_jint) \
502 \
503 product(intx, PrefetchScanIntervalInBytes, -1, \
504 "How far ahead to prefetch scan area (<= 0 means off)") \
505 range(-1, max_jint) \
506 \
507 product(intx, PrefetchFieldsAhead, -1, \
508 "How many fields ahead to prefetch in oop scan (<= 0 means off)") \
509 range(-1, max_jint) \
510 \
511 product(bool, VerifyDuringStartup, false, DIAGNOSTIC, \
512 "Verify memory system before executing any Java code " \
513 "during VM initialization") \
514 \
515 product(bool, VerifyBeforeExit, trueInDebug, DIAGNOSTIC, \
516 "Verify system before exiting") \
517 \
518 product(bool, VerifyBeforeGC, false, DIAGNOSTIC, \
519 "Verify memory system before GC") \
520 \
521 product(bool, VerifyAfterGC, false, DIAGNOSTIC, \
522 "Verify memory system after GC") \
523 \
524 product(bool, VerifyDuringGC, false, DIAGNOSTIC, \
525 "Verify memory system during GC (between phases)") \
526 \
527 product(bool, VerifyArchivedFields, trueInDebug, DIAGNOSTIC, \
528 "Verify memory when archived oop fields are loaded from CDS)") \
529 \
530 product(ccstrlist, VerifyGCType, "", DIAGNOSTIC, \
531 "GC type(s) to verify when Verify*GC is enabled." \
532 "Available types are collector specific.") \
533 \
534 product(ccstrlist, VerifySubSet, "", DIAGNOSTIC, \
535 "Memory sub-systems to verify when Verify*GC flag(s) " \
536 "are enabled. One or more sub-systems can be specified " \
537 "in a comma separated string. Sub-systems are: " \
538 "threads, heap, symbol_table, string_table, codecache, " \
539 "dictionary, classloader_data_graph, metaspace, jni_handles, " \
540 "codecache_oops, resolved_method_table, stringdedup") \
541 \
542 product(bool, GCParallelVerificationEnabled, true, DIAGNOSTIC, \
543 "Enable parallel memory system verification") \
544 \
545 product(bool, DeferInitialCardMark, false, DIAGNOSTIC, \
546 "When +ReduceInitialCardMarks, explicitly defer any that " \
547 "may arise from new_pre_store_barrier") \
548 \
549 product(bool, UseCondCardMark, false, \
550 "Check for already marked card before updating card table") \
551 \
552 product(bool, VerifyRememberedSets, false, DIAGNOSTIC, \
553 "Verify GC remembered sets") \
554 \
555 product(bool, VerifyObjectStartArray, true, DIAGNOSTIC, \
556 "Verify GC object start array if verify before/after") \
557 \
558 product(bool, DisableExplicitGC, false, \
559 "Ignore calls to System.gc()") \
560 \
561 product(bool, PrintGC, false, \
562 "Print message at garbage collection. " \
563 "Deprecated, use -Xlog:gc instead.") \
564 \
565 product(bool, PrintGCDetails, false, \
566 "Print more details at garbage collection. " \
567 "Deprecated, use -Xlog:gc* instead.") \
568 \
569 develop(intx, ConcGCYieldTimeout, 0, \
570 "If non-zero, assert that GC threads yield within this " \
571 "number of milliseconds") \
572 range(0, max_intx) \
573 \
574 notproduct(intx, ScavengeALotInterval, 1, \
575 "Interval between which scavenge will occur with +ScavengeALot") \
576 \
577 notproduct(intx, FullGCALotInterval, 1, \
578 "Interval between which full gc will occur with +FullGCALot") \
579 \
580 notproduct(intx, FullGCALotStart, 0, \
581 "For which invocation to start FullGCAlot") \
582 \
583 notproduct(intx, FullGCALotDummies, 32*K, \
584 "Dummy object allocated with +FullGCALot, forcing all objects " \
585 "to move") \
586 \
587 /* gc parameters */ \
588 product(size_t, MinHeapSize, 0, \
589 "Minimum heap size (in bytes); zero means use ergonomics") \
590 constraint(MinHeapSizeConstraintFunc,AfterErgo) \
591 \
592 product(size_t, InitialHeapSize, 0, \
593 "Initial heap size (in bytes); zero means use ergonomics") \
594 constraint(InitialHeapSizeConstraintFunc,AfterErgo) \
595 \
596 product(size_t, MaxHeapSize, ScaleForWordSize(96*M), \
597 "Maximum heap size (in bytes)") \
598 constraint(MaxHeapSizeConstraintFunc,AfterErgo) \
599 \
600 product(size_t, SoftMaxHeapSize, 0, MANAGEABLE, \
601 "Soft limit for maximum heap size (in bytes)") \
602 constraint(SoftMaxHeapSizeConstraintFunc,AfterMemoryInit) \
603 \
604 product(size_t, OldSize, ScaleForWordSize(4*M), \
605 "Initial tenured generation size (in bytes)") \
606 range(0, max_uintx) \
607 \
608 product(size_t, NewSize, ScaleForWordSize(1*M), \
609 "Initial new generation size (in bytes)") \
610 constraint(NewSizeConstraintFunc,AfterErgo) \
611 \
612 product(size_t, MaxNewSize, max_uintx, \
613 "Maximum new generation size (in bytes), max_uintx means set " \
614 "ergonomically") \
615 range(0, max_uintx) \
616 \
617 product_pd(size_t, HeapBaseMinAddress, \
618 "OS specific low limit for heap base address") \
619 constraint(HeapBaseMinAddressConstraintFunc,AfterErgo) \
620 \
621 product(size_t, PretenureSizeThreshold, 0, \
622 "Maximum size in bytes of objects allocated in DefNew " \
623 "generation; zero means no maximum") \
624 range(0, max_uintx) \
625 \
626 product(uintx, SurvivorRatio, 8, \
627 "Ratio of eden/survivor space size") \
628 range(1, max_uintx-2) \
629 constraint(SurvivorRatioConstraintFunc,AfterMemoryInit) \
630 \
631 product(uintx, NewRatio, 2, \
632 "Ratio of old/new generation sizes") \
633 range(0, max_uintx-1) \
634 \
635 product_pd(size_t, NewSizeThreadIncrease, \
636 "Additional size added to desired new generation size per " \
637 "non-daemon thread (in bytes)") \
638 range(0, max_uintx) \
639 \
640 product(uintx, QueuedAllocationWarningCount, 0, \
641 "Number of times an allocation that queues behind a GC " \
642 "will retry before printing a warning") \
643 range(0, max_uintx) \
644 \
645 product(uintx, VerifyGCStartAt, 0, DIAGNOSTIC, \
646 "GC invoke count where +VerifyBefore/AfterGC kicks in") \
647 range(0, max_uintx) \
648 \
649 product(intx, VerifyGCLevel, 0, DIAGNOSTIC, \
650 "Generation level at which to start +VerifyBefore/AfterGC") \
651 range(0, 1) \
652 \
653 product(uintx, MaxTenuringThreshold, 15, \
654 "Maximum value for tenuring threshold") \
655 range(0, markWord::max_age + 1) \
656 constraint(MaxTenuringThresholdConstraintFunc,AfterErgo) \
657 \
658 product(uintx, InitialTenuringThreshold, 7, \
659 "Initial value for tenuring threshold") \
660 range(0, markWord::max_age + 1) \
661 constraint(InitialTenuringThresholdConstraintFunc,AfterErgo) \
662 \
663 product(uintx, TargetSurvivorRatio, 50, \
664 "Desired percentage of survivor space used after scavenge") \
665 range(0, 100) \
666 \
667 product(uintx, MarkSweepDeadRatio, 5, \
668 "Percentage (0-100) of the old gen allowed as dead wood. " \
669 "Serial mark sweep treats this as both the minimum and maximum " \
670 "value. " \
671 "Par compact uses a variable scale based on the density of the " \
672 "generation and treats this as the maximum value when the heap " \
673 "is either completely full or completely empty. Par compact " \
674 "also has a smaller default value; see arguments.cpp. " \
675 "G1 full gc treats this as an allowed garbage threshold to skip " \
676 "compaction of heap regions, i.e. if a heap region has less " \
677 "garbage than this value, then the region will not be compacted" \
678 "during G1 full GC.") \
679 range(0, 100) \
680 \
681 product(uint, MarkSweepAlwaysCompactCount, 4, \
682 "How often should we fully compact the heap (ignoring the dead " \
683 "space parameters)") \
684 range(1, max_juint) \
685 \
686 develop(uintx, GCExpandToAllocateDelayMillis, 0, \
687 "Delay between expansion and allocation (in milliseconds)") \
688 \
689 product(uintx, GCDrainStackTargetSize, 64, \
690 "Number of entries we will try to leave on the stack " \
691 "during parallel gc") \
692 range(0, max_juint)
693
694 // end of GC_FLAGS
695
696 DECLARE_FLAGS(GC_FLAGS)
697
698 #endif // SHARE_GC_SHARED_GC_GLOBALS_HPP