1 /*
2 * Copyright (c) 1997, 2023, 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/shared/z_shared_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_SHARED_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, ZGenerational, false, \
129 "Use the generational version of ZGC") \
130 \
131 product(bool, UseShenandoahGC, false, \
132 "Use the Shenandoah garbage collector") \
133 \
134 product(uint, ParallelGCThreads, 0, \
135 "Number of parallel threads parallel gc will use") \
136 constraint(ParallelGCThreadsConstraintFunc,AfterErgo) \
137 \
138 product(bool, UseDynamicNumberOfGCThreads, true, \
139 "Dynamically choose the number of threads up to a maximum of " \
140 "ParallelGCThreads parallel collectors will use for garbage " \
141 "collection work") \
142 \
143 product(bool, InjectGCWorkerCreationFailure, false, DIAGNOSTIC, \
144 "Inject thread creation failures for " \
145 "UseDynamicNumberOfGCThreads") \
146 \
147 product(size_t, HeapSizePerGCThread, ScaleForWordSize(32*M), \
148 "Size of heap (bytes) per GC thread used in calculating the " \
149 "number of GC threads") \
150 constraint(VMPageSizeConstraintFunc, AtParse) \
151 \
152 product(uint, ConcGCThreads, 0, \
153 "Number of threads concurrent gc will use") \
154 \
155 product(bool, AlwaysTenure, false, \
156 "Always tenure objects in eden (ParallelGC only)") \
157 \
158 product(bool, NeverTenure, false, \
159 "Never tenure objects in eden, may tenure on overflow " \
160 "(ParallelGC only)") \
161 \
162 product(bool, ScavengeBeforeFullGC, true, \
163 "Scavenge youngest generation before each full GC.") \
164 \
165 product(bool, ExplicitGCInvokesConcurrent, false, \
166 "A System.gc() request invokes a concurrent collection; " \
167 "(effective only when using concurrent collectors)") \
168 \
169 product(uintx, GCLockerEdenExpansionPercent, 5, \
170 "How much the GC can expand the eden by while the GC locker " \
171 "is active (as a percentage)") \
172 range(0, 100) \
173 \
174 product(uintx, GCLockerRetryAllocationCount, 2, DIAGNOSTIC, \
175 "Number of times to retry allocations when " \
176 "blocked by the GC locker") \
177 range(0, max_uintx) \
178 \
179 product(uintx, ParallelGCBufferWastePct, 10, \
180 "Wasted fraction of parallel allocation buffer") \
181 range(0, 100) \
182 \
183 product(uintx, TargetPLABWastePct, 10, \
184 "Target wasted space in last buffer as percent of overall " \
185 "allocation") \
186 range(1, 100) \
187 \
188 product(uintx, PLABWeight, 75, \
189 "Percentage (0-100) used to weight the current sample when " \
190 "computing exponentially decaying average for ResizePLAB") \
191 range(0, 100) \
192 \
193 product(bool, ResizePLAB, true, \
194 "Dynamically resize (survivor space) promotion LAB's") \
195 \
196 product(int, ParGCArrayScanChunk, 50, \
197 "Scan a subset of object array and push remainder, if array is " \
198 "bigger than this") \
199 range(1, max_jint/3) \
200 \
201 \
202 product(bool, AlwaysPreTouch, false, \
203 "Force all freshly committed pages to be pre-touched") \
204 \
205 product(bool, AlwaysPreTouchStacks, false, DIAGNOSTIC, \
206 "Force java thread stacks to be fully pre-touched") \
207 \
208 product_pd(size_t, PreTouchParallelChunkSize, \
209 "Per-thread chunk size for parallel memory pre-touch.") \
210 range(4*K, SIZE_MAX / 2) \
211 \
212 /* where does the range max value of (max_jint - 1) come from? */ \
213 product(size_t, MarkStackSizeMax, NOT_LP64(4*M) LP64_ONLY(512*M), \
214 "Maximum size of marking stack") \
215 range(1, (max_jint - 1)) \
216 \
217 product(size_t, MarkStackSize, NOT_LP64(64*K) LP64_ONLY(4*M), \
218 "Size of marking stack") \
219 constraint(MarkStackSizeConstraintFunc,AfterErgo) \
220 range(1, (max_jint - 1)) \
221 \
222 product(bool, ParallelRefProcEnabled, false, \
223 "Enable parallel reference processing whenever possible") \
224 \
225 product(bool, ParallelRefProcBalancingEnabled, true, \
226 "Enable balancing of reference processing queues") \
227 \
228 product(size_t, ReferencesPerThread, 1000, EXPERIMENTAL, \
229 "Ergonomically start one thread for this amount of " \
230 "references for reference processing if " \
231 "ParallelRefProcEnabled is true. Specify 0 to disable and " \
232 "use all threads.") \
233 \
234 product(uintx, InitiatingHeapOccupancyPercent, 45, \
235 "The percent occupancy (IHOP) of the current old generation " \
236 "capacity above which a concurrent mark cycle will be initiated " \
237 "Its value may change over time if adaptive IHOP is enabled, " \
238 "otherwise the value remains constant. " \
239 "In the latter case a value of 0 will result as frequent as " \
240 "possible concurrent marking cycles. A value of 100 disables " \
241 "concurrent marking. " \
242 "Fragmentation waste in the old generation is not considered " \
243 "free space in this calculation. (G1 collector only)") \
244 range(0, 100) \
245 \
246 notproduct(bool, ScavengeALot, false, \
247 "Force scavenge at every Nth exit from the runtime system " \
248 "(N=ScavengeALotInterval)") \
249 \
250 develop(bool, FullGCALot, false, \
251 "Force full gc at every Nth exit from the runtime system " \
252 "(N=FullGCALotInterval)") \
253 \
254 notproduct(bool, GCALotAtAllSafepoints, false, \
255 "Enforce ScavengeALot/GCALot at all potential safepoints") \
256 \
257 notproduct(bool, PromotionFailureALot, false, \
258 "Use promotion failure handling on every youngest generation " \
259 "collection") \
260 \
261 develop(uintx, PromotionFailureALotCount, 1000, \
262 "Number of promotion failures occurring at PLAB promotion " \
263 "attempts at young collectors") \
264 \
265 develop(uintx, PromotionFailureALotInterval, 5, \
266 "Total collections between promotion failures a lot") \
267 \
268 product(uintx, WorkStealingSleepMillis, 1, EXPERIMENTAL, \
269 "Sleep time when sleep is used for yields") \
270 \
271 product(uintx, WorkStealingYieldsBeforeSleep, 5000, EXPERIMENTAL, \
272 "Number of yields before a sleep is done during work stealing") \
273 \
274 product(uintx, WorkStealingHardSpins, 4096, EXPERIMENTAL, \
275 "Number of iterations in a spin loop between checks on " \
276 "time out of hard spin") \
277 \
278 product(uintx, WorkStealingSpinToYieldRatio, 10, EXPERIMENTAL, \
279 "Ratio of hard spins to calls to yield") \
280 \
281 develop(uintx, ObjArrayMarkingStride, 2048, \
282 "Number of object array elements to push onto the marking stack " \
283 "before pushing a continuation entry") \
284 \
285 develop(bool, MetadataAllocationFailALot, false, \
286 "Fail metadata allocations at intervals controlled by " \
287 "MetadataAllocationFailALotInterval") \
288 \
289 develop(uintx, MetadataAllocationFailALotInterval, 1000, \
290 "Metadata allocation failure a lot interval") \
291 \
292 product_pd(bool, NeverActAsServerClassMachine, \
293 "Never act like a server-class machine") \
294 \
295 product(bool, AlwaysActAsServerClassMachine, false, \
296 "Always act like a server-class machine") \
297 \
298 product_pd(uint64_t, MaxRAM, \
299 "Real memory size (in bytes) used to set maximum heap size") \
300 range(0, 0XFFFFFFFFFFFFFFFF) \
301 \
302 product(bool, AggressiveHeap, false, \
303 "Optimize heap options for long-running memory intensive apps") \
304 \
305 product(size_t, ErgoHeapSizeLimit, 0, \
306 "Maximum ergonomically set heap size (in bytes); zero means use " \
307 "MaxRAM * MaxRAMPercentage / 100") \
308 range(0, max_uintx) \
309 \
310 product(uintx, MaxRAMFraction, 4, \
311 "Maximum fraction (1/n) of real memory used for maximum heap " \
312 "size. " \
313 "Deprecated, use MaxRAMPercentage instead") \
314 range(1, max_uintx) \
315 \
316 product(uintx, MinRAMFraction, 2, \
317 "Minimum fraction (1/n) of real memory used for maximum heap " \
318 "size on systems with small physical memory size. " \
319 "Deprecated, use MinRAMPercentage instead") \
320 range(1, max_uintx) \
321 \
322 product(uintx, InitialRAMFraction, 64, \
323 "Fraction (1/n) of real memory used for initial heap size. " \
324 "Deprecated, use InitialRAMPercentage instead") \
325 range(1, max_uintx) \
326 \
327 product(double, MaxRAMPercentage, 25.0, \
328 "Maximum percentage of real memory used for maximum heap size") \
329 range(0.0, 100.0) \
330 \
331 product(double, MinRAMPercentage, 50.0, \
332 "Minimum percentage of real memory used for maximum heap" \
333 "size on systems with small physical memory size") \
334 range(0.0, 100.0) \
335 \
336 product(double, InitialRAMPercentage, 1.5625, \
337 "Percentage of real memory used for initial heap size") \
338 range(0.0, 100.0) \
339 \
340 product(int, ActiveProcessorCount, -1, \
341 "Specify the CPU count the VM should use and report as active") \
342 \
343 develop(uintx, MaxVirtMemFraction, 2, \
344 "Maximum fraction (1/n) of virtual memory used for ergonomically "\
345 "determining maximum heap size") \
346 range(1, max_uintx) \
347 \
348 product(bool, UseAdaptiveSizePolicy, true, \
349 "Use adaptive generation sizing policies") \
350 \
351 product(bool, UsePSAdaptiveSurvivorSizePolicy, true, \
352 "Use adaptive survivor sizing policies") \
353 \
354 product(bool, UseAdaptiveGenerationSizePolicyAtMinorCollection, true, \
355 "Use adaptive young-old sizing policies at minor collections") \
356 \
357 product(bool, UseAdaptiveGenerationSizePolicyAtMajorCollection, true, \
358 "Use adaptive young-old sizing policies at major collections") \
359 \
360 product(bool, UseAdaptiveSizePolicyWithSystemGC, false, \
361 "Include statistics from System.gc() for adaptive size policy") \
362 \
363 develop(intx, PSAdaptiveSizePolicyResizeVirtualSpaceAlot, -1, \
364 "Resize the virtual spaces of the young or old generations") \
365 range(-1, 1) \
366 \
367 product(uintx, AdaptiveSizeThroughPutPolicy, 0, \
368 "Policy for changing generation size for throughput goals") \
369 range(0, 1) \
370 \
371 product(uintx, AdaptiveSizePolicyInitializingSteps, 20, \
372 "Number of steps where heuristics is used before data is used") \
373 range(0, max_uintx) \
374 \
375 develop(uintx, AdaptiveSizePolicyReadyThreshold, 5, \
376 "Number of collections before the adaptive sizing is started") \
377 \
378 product(uintx, AdaptiveSizePolicyOutputInterval, 0, \
379 "Collection interval for printing information; zero means never") \
380 range(0, max_uintx) \
381 \
382 product(bool, UseAdaptiveSizePolicyFootprintGoal, true, \
383 "Use adaptive minimum footprint as a goal") \
384 \
385 product(uintx, AdaptiveSizePolicyWeight, 10, \
386 "Weight given to exponential resizing, between 0 and 100") \
387 range(0, 100) \
388 \
389 product(uintx, AdaptiveTimeWeight, 25, \
390 "Weight given to time in adaptive policy, between 0 and 100") \
391 range(0, 100) \
392 \
393 product(uintx, PausePadding, 1, \
394 "How much buffer to keep for pause time") \
395 range(0, max_juint) \
396 \
397 product(uintx, PromotedPadding, 3, \
398 "How much buffer to keep for promotion failure") \
399 range(0, max_juint) \
400 \
401 product(uintx, SurvivorPadding, 3, \
402 "How much buffer to keep for survivor overflow") \
403 range(0, max_juint) \
404 \
405 product(uintx, ThresholdTolerance, 10, \
406 "Allowed collection cost difference between generations") \
407 range(0, 100) \
408 \
409 product(uintx, AdaptiveSizePolicyCollectionCostMargin, 50, \
410 "If collection costs are within margin, reduce both by full " \
411 "delta") \
412 range(0, 100) \
413 \
414 product(uintx, YoungGenerationSizeIncrement, 20, \
415 "Adaptive size percentage change in young generation") \
416 range(0, 100) \
417 \
418 product(uintx, YoungGenerationSizeSupplement, 80, \
419 "Supplement to YoungedGenerationSizeIncrement used at startup") \
420 range(0, 100) \
421 \
422 product(uintx, YoungGenerationSizeSupplementDecay, 8, \
423 "Decay factor to YoungedGenerationSizeSupplement") \
424 range(1, max_uintx) \
425 \
426 product(uintx, TenuredGenerationSizeIncrement, 20, \
427 "Adaptive size percentage change in tenured generation") \
428 range(0, 100) \
429 \
430 product(uintx, TenuredGenerationSizeSupplement, 80, \
431 "Supplement to TenuredGenerationSizeIncrement used at startup") \
432 range(0, 100) \
433 \
434 product(uintx, TenuredGenerationSizeSupplementDecay, 2, \
435 "Decay factor to TenuredGenerationSizeIncrement") \
436 range(1, max_uintx) \
437 \
438 product(uintx, MaxGCPauseMillis, max_uintx - 1, \
439 "Adaptive size policy maximum GC pause time goal in millisecond, "\
440 "or (G1 Only) the maximum GC time per MMU time slice") \
441 range(1, max_uintx - 1) \
442 constraint(MaxGCPauseMillisConstraintFunc,AfterErgo) \
443 \
444 product(uintx, GCPauseIntervalMillis, 0, \
445 "Time slice for MMU specification") \
446 constraint(GCPauseIntervalMillisConstraintFunc,AfterErgo) \
447 \
448 product(uintx, MaxGCMinorPauseMillis, max_uintx, \
449 "Adaptive size policy maximum GC minor pause time goal " \
450 "in millisecond") \
451 range(0, max_uintx) \
452 \
453 product(uintx, GCTimeRatio, 99, \
454 "Adaptive size policy application time to GC time ratio") \
455 range(0, max_juint) \
456 \
457 product(uintx, AdaptiveSizeDecrementScaleFactor, 4, \
458 "Adaptive size scale down factor for shrinking") \
459 range(1, max_uintx) \
460 \
461 product(bool, UseAdaptiveSizeDecayMajorGCCost, true, \
462 "Adaptive size decays the major cost for long major intervals") \
463 \
464 product(uintx, AdaptiveSizeMajorGCDecayTimeScale, 10, \
465 "Time scale over which major costs decay") \
466 range(0, max_uintx) \
467 \
468 product(uintx, MinSurvivorRatio, 3, \
469 "Minimum ratio of young generation/survivor space size") \
470 range(3, max_uintx) \
471 \
472 product(uintx, InitialSurvivorRatio, 8, \
473 "Initial ratio of young generation/survivor space size") \
474 range(0, max_uintx) \
475 \
476 product(size_t, BaseFootPrintEstimate, 256*M, \
477 "Estimate of footprint other than Java Heap") \
478 range(0, max_uintx) \
479 \
480 product(bool, UseGCOverheadLimit, true, \
481 "Use policy to limit of proportion of time spent in GC " \
482 "before an OutOfMemory error is thrown") \
483 \
484 product(uintx, GCTimeLimit, 98, \
485 "Limit of the proportion of time spent in GC before " \
486 "an OutOfMemoryError is thrown (used with GCHeapFreeLimit)") \
487 range(0, 100) \
488 \
489 product(uintx, GCHeapFreeLimit, 2, \
490 "Minimum percentage of free space after a full GC before an " \
491 "OutOfMemoryError is thrown (used with GCTimeLimit)") \
492 range(0, 100) \
493 \
494 develop(uintx, GCOverheadLimitThreshold, 5, \
495 "Number of consecutive collections before gc time limit fires") \
496 range(1, max_uintx) \
497 \
498 product(intx, PrefetchCopyIntervalInBytes, -1, \
499 "How far ahead to prefetch destination area (<= 0 means off)") \
500 range(-1, max_jint) \
501 \
502 product(intx, PrefetchScanIntervalInBytes, -1, \
503 "How far ahead to prefetch scan area (<= 0 means off)") \
504 range(-1, max_jint) \
505 \
506 product(bool, VerifyDuringStartup, false, DIAGNOSTIC, \
507 "Verify memory system before executing any Java code " \
508 "during VM initialization") \
509 \
510 product(bool, VerifyBeforeExit, trueInDebug, DIAGNOSTIC, \
511 "Verify system before exiting") \
512 \
513 product(bool, VerifyBeforeGC, false, DIAGNOSTIC, \
514 "Verify memory system before GC") \
515 \
516 product(bool, VerifyAfterGC, false, DIAGNOSTIC, \
517 "Verify memory system after GC") \
518 \
519 product(bool, VerifyDuringGC, false, DIAGNOSTIC, \
520 "Verify memory system during GC (between phases)") \
521 \
522 product(int, VerifyArchivedFields, 0, DIAGNOSTIC, \
523 "Verify memory when archived oop fields are loaded from CDS; " \
524 "0: No check; " \
525 "1: Basic verification with VM_Verify (no side effects); " \
526 "2: Detailed verification by forcing a GC (with side effects)") \
527 range(0, 2) \
528 \
529 product(ccstrlist, VerifyGCType, "", DIAGNOSTIC, \
530 "GC type(s) to verify when Verify*GC is enabled." \
531 "Available types are collector specific.") \
532 \
533 product(ccstrlist, VerifySubSet, "", DIAGNOSTIC, \
534 "Memory sub-systems to verify when Verify*GC flag(s) " \
535 "are enabled. One or more sub-systems can be specified " \
536 "in a comma separated string. Sub-systems are: " \
537 "threads, heap, symbol_table, string_table, codecache, " \
538 "dictionary, classloader_data_graph, metaspace, jni_handles, " \
539 "codecache_oops, resolved_method_table, stringdedup") \
540 \
541 product(bool, DeferInitialCardMark, false, DIAGNOSTIC, \
542 "When +ReduceInitialCardMarks, explicitly defer any that " \
543 "may arise from new_pre_store_barrier") \
544 \
545 product(bool, UseCondCardMark, false, \
546 "Check for already marked card before updating card table") \
547 \
548 product(bool, VerifyRememberedSets, false, DIAGNOSTIC, \
549 "Verify GC remembered sets") \
550 \
551 product(bool, VerifyObjectStartArray, true, DIAGNOSTIC, \
552 "Verify GC object start array if verify before/after") \
553 \
554 product(bool, DisableExplicitGC, false, \
555 "Ignore calls to System.gc()") \
556 \
557 product(bool, PrintGC, false, \
558 "Print message at garbage collection. " \
559 "Deprecated, use -Xlog:gc instead.") \
560 \
561 product(bool, PrintGCDetails, false, \
562 "Print more details at garbage collection. " \
563 "Deprecated, use -Xlog:gc* instead.") \
564 \
565 develop(intx, ConcGCYieldTimeout, 0, \
566 "If non-zero, assert that GC threads yield within this " \
567 "number of milliseconds") \
568 range(0, max_intx) \
569 \
570 notproduct(intx, ScavengeALotInterval, 1, \
571 "Interval between which scavenge will occur with +ScavengeALot") \
572 \
573 notproduct(intx, FullGCALotInterval, 1, \
574 "Interval between which full gc will occur with +FullGCALot") \
575 \
576 notproduct(intx, FullGCALotStart, 0, \
577 "For which invocation to start FullGCAlot") \
578 \
579 notproduct(intx, FullGCALotDummies, 32*K, \
580 "Dummy object allocated with +FullGCALot, forcing all objects " \
581 "to move") \
582 \
583 /* gc parameters */ \
584 product(size_t, MinHeapSize, 0, \
585 "Minimum heap size (in bytes); zero means use ergonomics") \
586 constraint(MinHeapSizeConstraintFunc,AfterErgo) \
587 \
588 product(size_t, InitialHeapSize, 0, \
589 "Initial heap size (in bytes); zero means use ergonomics") \
590 constraint(InitialHeapSizeConstraintFunc,AfterErgo) \
591 \
592 product(size_t, MaxHeapSize, ScaleForWordSize(96*M), \
593 "Maximum heap size (in bytes)") \
594 constraint(MaxHeapSizeConstraintFunc,AfterErgo) \
595 \
596 product(size_t, SoftMaxHeapSize, 0, MANAGEABLE, \
597 "Soft limit for maximum heap size (in bytes)") \
598 constraint(SoftMaxHeapSizeConstraintFunc,AfterMemoryInit) \
599 \
600 product(size_t, OldSize, ScaleForWordSize(4*M), \
601 "Initial tenured generation size (in bytes)") \
602 range(0, max_uintx) \
603 \
604 product(size_t, NewSize, ScaleForWordSize(1*M), \
605 "Initial new generation size (in bytes)") \
606 constraint(NewSizeConstraintFunc,AfterErgo) \
607 \
608 product(size_t, MaxNewSize, max_uintx, \
609 "Maximum new generation size (in bytes), max_uintx means set " \
610 "ergonomically") \
611 range(0, max_uintx) \
612 \
613 product_pd(size_t, HeapBaseMinAddress, \
614 "OS specific low limit for heap base address") \
615 constraint(HeapBaseMinAddressConstraintFunc,AfterErgo) \
616 \
617 product(size_t, PretenureSizeThreshold, 0, \
618 "Maximum size in bytes of objects allocated in DefNew " \
619 "generation; zero means no maximum") \
620 range(0, max_uintx) \
621 \
622 product(uintx, SurvivorRatio, 8, \
623 "Ratio of eden/survivor space size") \
624 range(1, max_uintx-2) \
625 constraint(SurvivorRatioConstraintFunc,AfterMemoryInit) \
626 \
627 product(uintx, NewRatio, 2, \
628 "Ratio of old/new generation sizes") \
629 range(0, max_uintx-1) \
630 \
631 product_pd(size_t, NewSizeThreadIncrease, \
632 "Additional size added to desired new generation size per " \
633 "non-daemon thread (in bytes)") \
634 range(0, max_uintx) \
635 \
636 product(uintx, QueuedAllocationWarningCount, 0, \
637 "Number of times an allocation that queues behind a GC " \
638 "will retry before printing a warning") \
639 range(0, max_uintx) \
640 \
641 product(uintx, VerifyGCStartAt, 0, DIAGNOSTIC, \
642 "GC invoke count where +VerifyBefore/AfterGC kicks in") \
643 range(0, max_uintx) \
644 \
645 product(intx, VerifyGCLevel, 0, DIAGNOSTIC, \
646 "Generation level at which to start +VerifyBefore/AfterGC") \
647 range(0, 1) \
648 \
649 product(uintx, MaxTenuringThreshold, 15, \
650 "Maximum value for tenuring threshold") \
651 range(0, markWord::max_age + 1) \
652 constraint(MaxTenuringThresholdConstraintFunc,AfterErgo) \
653 \
654 product(uintx, InitialTenuringThreshold, 7, \
655 "Initial value for tenuring threshold") \
656 range(0, markWord::max_age + 1) \
657 constraint(InitialTenuringThresholdConstraintFunc,AfterErgo) \
658 \
659 product(uintx, TargetSurvivorRatio, 50, \
660 "Desired percentage of survivor space used after scavenge") \
661 range(0, 100) \
662 \
663 product(uintx, MarkSweepDeadRatio, 5, \
664 "Percentage (0-100) of the old gen allowed as dead wood. " \
665 "Serial mark sweep treats this as both the minimum and maximum " \
666 "value. " \
667 "Par compact uses a variable scale based on the density of the " \
668 "generation and treats this as the maximum value when the heap " \
669 "is either completely full or completely empty. Par compact " \
670 "also has a smaller default value; see arguments.cpp. " \
671 "G1 full gc treats this as an allowed garbage threshold to skip " \
672 "compaction of heap regions, i.e. if a heap region has less " \
673 "garbage than this value, then the region will not be compacted" \
674 "during G1 full GC.") \
675 range(0, 100) \
676 \
677 product(uint, MarkSweepAlwaysCompactCount, 4, \
678 "How often should we fully compact the heap (ignoring the dead " \
679 "space parameters)") \
680 range(1, max_juint) \
681 \
682 develop(uintx, GCExpandToAllocateDelayMillis, 0, \
683 "Delay between expansion and allocation (in milliseconds)") \
684 \
685 product(uintx, GCDrainStackTargetSize, 64, \
686 "Number of entries we will try to leave on the stack " \
687 "during parallel gc") \
688 range(0, max_juint) \
689 \
690 product(uint, GCCardSizeInBytes, 512, \
691 "Card table entry size (in bytes) for card based collectors") \
692 range(128, NOT_LP64(512) LP64_ONLY(1024)) \
693 constraint(GCCardSizeInBytesConstraintFunc,AtParse) \
694 \
695 product(bool, UseAltGCForwarding, false, EXPERIMENTAL, \
696 "Use alternative GC forwarding that preserves object headers") \
697
698 // end of GC_FLAGS
699
700 DECLARE_FLAGS(GC_FLAGS)
701
702 #endif // SHARE_GC_SHARED_GC_GLOBALS_HPP