30 #include "memory/collectorPolicy.hpp"
31 #include "memory/gcLocker.inline.hpp"
32 #include "memory/genCollectedHeap.hpp"
33 #include "memory/generationSpec.hpp"
34 #include "memory/space.hpp"
35 #include "memory/universe.hpp"
36 #include "runtime/arguments.hpp"
37 #include "runtime/globals_extension.hpp"
38 #include "runtime/handles.inline.hpp"
39 #include "runtime/java.hpp"
40 #include "runtime/thread.inline.hpp"
41 #include "runtime/vmThread.hpp"
42 #include "utilities/macros.hpp"
43 #if INCLUDE_ALL_GCS
44 #include "gc_implementation/concurrentMarkSweep/cmsAdaptiveSizePolicy.hpp"
45 #include "gc_implementation/concurrentMarkSweep/cmsGCAdaptivePolicyCounters.hpp"
46 #endif // INCLUDE_ALL_GCS
47
48 // CollectorPolicy methods.
49
50 void CollectorPolicy::initialize_flags() {
51 assert(_max_alignment >= _min_alignment,
52 err_msg("max_alignment: " SIZE_FORMAT " less than min_alignment: " SIZE_FORMAT,
53 _max_alignment, _min_alignment));
54 assert(_max_alignment % _min_alignment == 0,
55 err_msg("max_alignment: " SIZE_FORMAT " not aligned by min_alignment: " SIZE_FORMAT,
56 _max_alignment, _min_alignment));
57
58 if (MaxHeapSize < InitialHeapSize) {
59 vm_exit_during_initialization("Incompatible initial and maximum heap sizes specified");
60 }
61
62 MinHeapDeltaBytes = align_size_up(MinHeapDeltaBytes, _min_alignment);
63 }
64
65 void CollectorPolicy::initialize_size_info() {
66 // User inputs from -mx and ms must be aligned
67 _min_heap_byte_size = align_size_up(Arguments::min_heap_size(), _min_alignment);
68 _initial_heap_byte_size = align_size_up(InitialHeapSize, _min_alignment);
69 _max_heap_byte_size = align_size_up(MaxHeapSize, _max_alignment);
70
71 // Check heap parameter properties
72 if (_initial_heap_byte_size < M) {
73 vm_exit_during_initialization("Too small initial heap");
74 }
75 // Check heap parameter properties
76 if (_min_heap_byte_size < M) {
77 vm_exit_during_initialization("Too small minimum heap");
78 }
79 if (_initial_heap_byte_size <= NewSize) {
80 // make sure there is at least some room in old space
81 vm_exit_during_initialization("Too small initial heap for new size specified");
82 }
83 if (_max_heap_byte_size < _min_heap_byte_size) {
84 vm_exit_during_initialization("Incompatible minimum and maximum heap sizes specified");
85 }
86 if (_initial_heap_byte_size < _min_heap_byte_size) {
87 vm_exit_during_initialization("Incompatible minimum and initial heap sizes specified");
88 }
89 if (_max_heap_byte_size < _initial_heap_byte_size) {
90 vm_exit_during_initialization("Incompatible initial and maximum heap sizes specified");
91 }
92
93 if (PrintGCDetails && Verbose) {
94 gclog_or_tty->print_cr("Minimum heap " SIZE_FORMAT " Initial heap "
95 SIZE_FORMAT " Maximum heap " SIZE_FORMAT,
96 _min_heap_byte_size, _initial_heap_byte_size, _max_heap_byte_size);
97 }
98 }
99
100 bool CollectorPolicy::use_should_clear_all_soft_refs(bool v) {
101 bool result = _should_clear_all_soft_refs;
102 set_should_clear_all_soft_refs(false);
103 return result;
104 }
105
106 GenRemSet* CollectorPolicy::create_rem_set(MemRegion whole_heap,
107 int max_covered_regions) {
108 return new CardTableRS(whole_heap, max_covered_regions);
109 }
110
111 void CollectorPolicy::cleared_all_soft_refs() {
112 // If near gc overhear limit, continue to clear SoftRefs. SoftRefs may
113 // have been cleared in the last collection but if the gc overhear
114 // limit continues to be near, SoftRefs should still be cleared.
115 if (size_policy() != NULL) {
116 _should_clear_all_soft_refs = size_policy()->gc_overhead_limit_near();
117 }
118 _all_soft_refs_clear = true;
119 }
120
121 size_t CollectorPolicy::compute_max_alignment() {
122 // The card marking array and the offset arrays for old generations are
123 // committed in os pages as well. Make sure they are entirely full (to
124 // avoid partial page problems), e.g. if 512 bytes heap corresponds to 1
125 // byte entry and the os page size is 4096, the maximum heap size should
126 // be 512*4096 = 2MB aligned.
127
128 // There is only the GenRemSet in Hotspot and only the GenRemSet::CardTable
129 // is supported.
130 // Requirements of any new remembered set implementations must be added here.
131 size_t alignment = GenRemSet::max_alignment_constraint(GenRemSet::CardTable);
132
133 // Parallel GC does its own alignment of the generations to avoid requiring a
134 // large page (256M on some platforms) for the permanent generation. The
135 // other collectors should also be updated to do their own alignment and then
136 // this use of lcm() should be removed.
137 if (UseLargePages && !UseParallelGC) {
138 // in presence of large pages we have to make sure that our
139 // alignment is large page aware
140 alignment = lcm(os::large_page_size(), alignment);
141 }
142
143 return alignment;
144 }
145
146 // GenCollectorPolicy methods.
147
148 size_t GenCollectorPolicy::scale_by_NewRatio_aligned(size_t base_size) {
149 return align_size_down_bounded(base_size / (NewRatio + 1), _min_alignment);
150 }
151
152 size_t GenCollectorPolicy::bound_minus_alignment(size_t desired_size,
153 size_t maximum_size) {
154 size_t alignment = _min_alignment;
155 size_t max_minus = maximum_size - alignment;
156 return desired_size < max_minus ? desired_size : max_minus;
157 }
158
159
160 void GenCollectorPolicy::initialize_size_policy(size_t init_eden_size,
161 size_t init_promo_size,
162 size_t init_survivor_size) {
163 const double max_gc_pause_sec = ((double) MaxGCPauseMillis) / 1000.0;
164 _size_policy = new AdaptiveSizePolicy(init_eden_size,
165 init_promo_size,
166 init_survivor_size,
167 max_gc_pause_sec,
168 GCTimeRatio);
169 }
170
171 void GenCollectorPolicy::initialize_flags() {
172 // All sizes must be multiples of the generation granularity.
173 _min_alignment = (uintx) Generation::GenGrain;
174 _max_alignment = compute_max_alignment();
175
176 CollectorPolicy::initialize_flags();
177
178 // All generational heaps have a youngest gen; handle those flags here.
179
180 // Adjust max size parameters
181 if (NewSize > MaxNewSize) {
182 MaxNewSize = NewSize;
183 }
184 NewSize = align_size_down(NewSize, _min_alignment);
185 MaxNewSize = align_size_down(MaxNewSize, _min_alignment);
186
187 // Check validity of heap flags
188 assert(NewSize % _min_alignment == 0, "eden space alignment");
189 assert(MaxNewSize % _min_alignment == 0, "survivor space alignment");
190
191 if (NewSize < 3 * _min_alignment) {
192 // make sure there room for eden and two survivor spaces
193 vm_exit_during_initialization("Too small new size specified");
194 }
195
196 if (SurvivorRatio < 1 || NewRatio < 1) {
197 vm_exit_during_initialization("Invalid young gen ratio specified");
198 }
199 }
200
201 void TwoGenerationCollectorPolicy::initialize_flags() {
202 GenCollectorPolicy::initialize_flags();
203
204 OldSize = align_size_down(OldSize, _min_alignment);
205
206 if (FLAG_IS_CMDLINE(OldSize) && FLAG_IS_DEFAULT(NewSize)) {
207 // NewRatio will be used later to set the young generation size so we use
208 // it to calculate how big the heap should be based on the requested OldSize
209 // and NewRatio.
210 assert(NewRatio > 0, "NewRatio should have been set up earlier");
211 size_t calculated_heapsize = (OldSize / NewRatio) * (NewRatio + 1);
212
213 calculated_heapsize = align_size_up(calculated_heapsize, _max_alignment);
214 MaxHeapSize = calculated_heapsize;
215 InitialHeapSize = calculated_heapsize;
216 }
217 MaxHeapSize = align_size_up(MaxHeapSize, _max_alignment);
218
219 // adjust max heap size if necessary
220 if (NewSize + OldSize > MaxHeapSize) {
221 if (FLAG_IS_CMDLINE(MaxHeapSize)) {
222 // somebody set a maximum heap size with the intention that we should not
223 // exceed it. Adjust New/OldSize as necessary.
224 uintx calculated_size = NewSize + OldSize;
225 double shrink_factor = (double) MaxHeapSize / calculated_size;
226 // align
227 NewSize = align_size_down((uintx) (NewSize * shrink_factor), _min_alignment);
228 // OldSize is already aligned because above we aligned MaxHeapSize to
229 // _max_alignment, and we just made sure that NewSize is aligned to
230 // _min_alignment. In initialize_flags() we verified that _max_alignment
231 // is a multiple of _min_alignment.
232 OldSize = MaxHeapSize - NewSize;
233 } else {
234 MaxHeapSize = NewSize + OldSize;
235 }
236 }
237 // need to do this again
238 MaxHeapSize = align_size_up(MaxHeapSize, _max_alignment);
239
240 // adjust max heap size if necessary
241 if (NewSize + OldSize > MaxHeapSize) {
242 if (FLAG_IS_CMDLINE(MaxHeapSize)) {
243 // somebody set a maximum heap size with the intention that we should not
244 // exceed it. Adjust New/OldSize as necessary.
245 uintx calculated_size = NewSize + OldSize;
246 double shrink_factor = (double) MaxHeapSize / calculated_size;
247 // align
248 NewSize = align_size_down((uintx) (NewSize * shrink_factor), _min_alignment);
249 // OldSize is already aligned because above we aligned MaxHeapSize to
250 // _max_alignment, and we just made sure that NewSize is aligned to
251 // _min_alignment. In initialize_flags() we verified that _max_alignment
252 // is a multiple of _min_alignment.
253 OldSize = MaxHeapSize - NewSize;
254 } else {
255 MaxHeapSize = NewSize + OldSize;
256 }
257 }
258 // need to do this again
259 MaxHeapSize = align_size_up(MaxHeapSize, _max_alignment);
260
261 always_do_update_barrier = UseConcMarkSweepGC;
262
263 // Check validity of heap flags
264 assert(OldSize % _min_alignment == 0, "old space alignment");
265 assert(MaxHeapSize % _max_alignment == 0, "maximum heap alignment");
266 }
267
268 // Values set on the command line win over any ergonomically
269 // set command line parameters.
270 // Ergonomic choice of parameters are done before this
271 // method is called. Values for command line parameters such as NewSize
272 // and MaxNewSize feed those ergonomic choices into this method.
273 // This method makes the final generation sizings consistent with
274 // themselves and with overall heap sizings.
275 // In the absence of explicitly set command line flags, policies
276 // such as the use of NewRatio are used to size the generation.
277 void GenCollectorPolicy::initialize_size_info() {
278 CollectorPolicy::initialize_size_info();
279
280 // _min_alignment is used for alignment within a generation.
281 // There is additional alignment done down stream for some
282 // collectors that sometimes causes unwanted rounding up of
283 // generations sizes.
284
285 // Determine maximum size of gen0
286
287 size_t max_new_size = 0;
288 if (FLAG_IS_CMDLINE(MaxNewSize) || FLAG_IS_ERGO(MaxNewSize)) {
289 if (MaxNewSize < _min_alignment) {
290 max_new_size = _min_alignment;
291 }
292 if (MaxNewSize >= _max_heap_byte_size) {
293 max_new_size = align_size_down(_max_heap_byte_size - _min_alignment,
294 _min_alignment);
295 warning("MaxNewSize (" SIZE_FORMAT "k) is equal to or "
296 "greater than the entire heap (" SIZE_FORMAT "k). A "
297 "new generation size of " SIZE_FORMAT "k will be used.",
298 MaxNewSize/K, _max_heap_byte_size/K, max_new_size/K);
299 } else {
300 max_new_size = align_size_down(MaxNewSize, _min_alignment);
301 }
302
303 // The case for FLAG_IS_ERGO(MaxNewSize) could be treated
304 // specially at this point to just use an ergonomically set
305 // MaxNewSize to set max_new_size. For cases with small
306 // heaps such a policy often did not work because the MaxNewSize
307 // was larger than the entire heap. The interpretation given
308 // to ergonomically set flags is that the flags are set
309 // by different collectors for their own special needs but
310 // are not allowed to badly shape the heap. This allows the
311 // different collectors to decide what's best for themselves
312 // without having to factor in the overall heap shape. It
313 // can be the case in the future that the collectors would
314 // only make "wise" ergonomics choices and this policy could
315 // just accept those choices. The choices currently made are
316 // not always "wise".
317 } else {
318 max_new_size = scale_by_NewRatio_aligned(_max_heap_byte_size);
319 // Bound the maximum size by NewSize below (since it historically
320 // would have been NewSize and because the NewRatio calculation could
321 // yield a size that is too small) and bound it by MaxNewSize above.
322 // Ergonomics plays here by previously calculating the desired
323 // NewSize and MaxNewSize.
324 max_new_size = MIN2(MAX2(max_new_size, NewSize), MaxNewSize);
325 }
326 assert(max_new_size > 0, "All paths should set max_new_size");
327
328 // Given the maximum gen0 size, determine the initial and
329 // minimum gen0 sizes.
330
331 if (_max_heap_byte_size == _min_heap_byte_size) {
332 // The maximum and minimum heap sizes are the same so
333 // the generations minimum and initial must be the
334 // same as its maximum.
335 _min_gen0_size = max_new_size;
336 _initial_gen0_size = max_new_size;
365 _max_gen0_size = max_new_size;
366
367 // At this point the desirable initial and minimum sizes have been
368 // determined without regard to the maximum sizes.
369
370 // Bound the sizes by the corresponding overall heap sizes.
371 _min_gen0_size = bound_minus_alignment(_min_gen0_size, _min_heap_byte_size);
372 _initial_gen0_size = bound_minus_alignment(_initial_gen0_size, _initial_heap_byte_size);
373 _max_gen0_size = bound_minus_alignment(_max_gen0_size, _max_heap_byte_size);
374
375 // At this point all three sizes have been checked against the
376 // maximum sizes but have not been checked for consistency
377 // among the three.
378
379 // Final check min <= initial <= max
380 _min_gen0_size = MIN2(_min_gen0_size, _max_gen0_size);
381 _initial_gen0_size = MAX2(MIN2(_initial_gen0_size, _max_gen0_size), _min_gen0_size);
382 _min_gen0_size = MIN2(_min_gen0_size, _initial_gen0_size);
383 }
384
385 if (PrintGCDetails && Verbose) {
386 gclog_or_tty->print_cr("1: Minimum gen0 " SIZE_FORMAT " Initial gen0 "
387 SIZE_FORMAT " Maximum gen0 " SIZE_FORMAT,
388 _min_gen0_size, _initial_gen0_size, _max_gen0_size);
389 }
390 }
391
392 // Call this method during the sizing of the gen1 to make
393 // adjustments to gen0 because of gen1 sizing policy. gen0 initially has
394 // the most freedom in sizing because it is done before the
395 // policy for gen1 is applied. Once gen1 policies have been applied,
396 // there may be conflicts in the shape of the heap and this method
397 // is used to make the needed adjustments. The application of the
398 // policies could be more sophisticated (iterative for example) but
399 // keeping it simple also seems a worthwhile goal.
400 bool TwoGenerationCollectorPolicy::adjust_gen0_sizes(size_t* gen0_size_ptr,
401 size_t* gen1_size_ptr,
402 const size_t heap_size,
403 const size_t min_gen1_size) {
404 bool result = false;
405
406 if ((*gen1_size_ptr + *gen0_size_ptr) > heap_size) {
407 if ((heap_size < (*gen0_size_ptr + min_gen1_size)) &&
408 (heap_size >= min_gen1_size + _min_alignment)) {
409 // Adjust gen0 down to accommodate min_gen1_size
410 *gen0_size_ptr = align_size_down_bounded(heap_size - min_gen1_size, _min_alignment);
411 assert(*gen0_size_ptr > 0, "Min gen0 is too large");
412 result = true;
413 } else {
414 *gen1_size_ptr = align_size_down_bounded(heap_size - *gen0_size_ptr, _min_alignment);
415 }
416 }
417 return result;
418 }
419
420 // Minimum sizes of the generations may be different than
421 // the initial sizes. An inconsistently is permitted here
422 // in the total size that can be specified explicitly by
423 // command line specification of OldSize and NewSize and
424 // also a command line specification of -Xms. Issue a warning
425 // but allow the values to pass.
426
427 void TwoGenerationCollectorPolicy::initialize_size_info() {
428 GenCollectorPolicy::initialize_size_info();
429
430 // At this point the minimum, initial and maximum sizes
431 // of the overall heap and of gen0 have been determined.
432 // The maximum gen1 size can be determined from the maximum gen0
433 // and maximum heap size since no explicit flags exits
434 // for setting the gen1 maximum.
435 _max_gen1_size = _max_heap_byte_size - _max_gen0_size;
436 _max_gen1_size =
437 MAX2((uintx)align_size_down(_max_gen1_size, _min_alignment), _min_alignment);
438 // If no explicit command line flag has been set for the
439 // gen1 size, use what is left for gen1.
440 if (FLAG_IS_DEFAULT(OldSize) || FLAG_IS_ERGO(OldSize)) {
441 // The user has not specified any value or ergonomics
442 // has chosen a value (which may or may not be consistent
443 // with the overall heap size). In either case make
444 // the minimum, maximum and initial sizes consistent
445 // with the gen0 sizes and the overall heap sizes.
446 assert(_min_heap_byte_size > _min_gen0_size,
447 "gen0 has an unexpected minimum size");
448 _min_gen1_size = _min_heap_byte_size - _min_gen0_size;
449 _min_gen1_size =
450 MAX2((uintx)align_size_down(_min_gen1_size, _min_alignment), _min_alignment);
451 _initial_gen1_size = _initial_heap_byte_size - _initial_gen0_size;
452 _initial_gen1_size =
453 MAX2((uintx)align_size_down(_initial_gen1_size, _min_alignment), _min_alignment);
454 } else {
455 // It's been explicitly set on the command line. Use the
456 // OldSize and then determine the consequences.
457 _min_gen1_size = OldSize;
458 _initial_gen1_size = OldSize;
459
460 // If the user has explicitly set an OldSize that is inconsistent
461 // with other command line flags, issue a warning.
462 // The generation minimums and the overall heap mimimum should
463 // be within one heap alignment.
464 if ((_min_gen1_size + _min_gen0_size + _min_alignment) < _min_heap_byte_size) {
465 warning("Inconsistency between minimum heap size and minimum "
466 "generation sizes: using minimum heap = " SIZE_FORMAT,
467 _min_heap_byte_size);
468 }
469 if (OldSize > _max_gen1_size) {
470 warning("Inconsistency between maximum heap size and maximum "
471 "generation sizes: using maximum heap = " SIZE_FORMAT
472 " -XX:OldSize flag is being ignored",
473 _max_heap_byte_size);
474 }
475 // If there is an inconsistency between the OldSize and the minimum and/or
476 // initial size of gen0, since OldSize was explicitly set, OldSize wins.
477 if (adjust_gen0_sizes(&_min_gen0_size, &_min_gen1_size,
478 _min_heap_byte_size, OldSize)) {
479 if (PrintGCDetails && Verbose) {
480 gclog_or_tty->print_cr("2: Minimum gen0 " SIZE_FORMAT " Initial gen0 "
481 SIZE_FORMAT " Maximum gen0 " SIZE_FORMAT,
482 _min_gen0_size, _initial_gen0_size, _max_gen0_size);
483 }
484 }
485 // Initial size
486 if (adjust_gen0_sizes(&_initial_gen0_size, &_initial_gen1_size,
487 _initial_heap_byte_size, OldSize)) {
488 if (PrintGCDetails && Verbose) {
489 gclog_or_tty->print_cr("3: Minimum gen0 " SIZE_FORMAT " Initial gen0 "
490 SIZE_FORMAT " Maximum gen0 " SIZE_FORMAT,
491 _min_gen0_size, _initial_gen0_size, _max_gen0_size);
492 }
493 }
494 }
495 // Enforce the maximum gen1 size.
496 _min_gen1_size = MIN2(_min_gen1_size, _max_gen1_size);
497
498 // Check that min gen1 <= initial gen1 <= max gen1
499 _initial_gen1_size = MAX2(_initial_gen1_size, _min_gen1_size);
500 _initial_gen1_size = MIN2(_initial_gen1_size, _max_gen1_size);
501
502 if (PrintGCDetails && Verbose) {
503 gclog_or_tty->print_cr("Minimum gen1 " SIZE_FORMAT " Initial gen1 "
504 SIZE_FORMAT " Maximum gen1 " SIZE_FORMAT,
505 _min_gen1_size, _initial_gen1_size, _max_gen1_size);
506 }
507 }
508
509 HeapWord* GenCollectorPolicy::mem_allocate_work(size_t size,
510 bool is_tlab,
511 bool* gc_overhead_limit_was_exceeded) {
512 GenCollectedHeap *gch = GenCollectedHeap::heap();
513
514 debug_only(gch->check_for_valid_allocation_state());
515 assert(gch->no_gc_in_progress(), "Allocation during gc not allowed");
516
517 // In general gc_overhead_limit_was_exceeded should be false so
518 // set it so here and reset it to true only if the gc time
519 // limit is being exceeded as checked below.
520 *gc_overhead_limit_was_exceeded = false;
521
522 HeapWord* result = NULL;
523
524 // Loop until the allocation is satisified,
525 // or unsatisfied after GC.
526 for (int try_count = 1, gclocker_stalled_count = 0; /* return or throw */; try_count += 1) {
809 // Return true if any of the following is true:
810 // . the allocation won't fit into the current young gen heap
811 // . gc locker is occupied (jni critical section)
812 // . heap memory is tight -- the most recent previous collection
813 // was a full collection because a partial collection (would
814 // have) failed and is likely to fail again
815 bool GenCollectorPolicy::should_try_older_generation_allocation(
816 size_t word_size) const {
817 GenCollectedHeap* gch = GenCollectedHeap::heap();
818 size_t gen0_capacity = gch->get_gen(0)->capacity_before_gc();
819 return (word_size > heap_word_size(gen0_capacity))
820 || GC_locker::is_active_and_needs_gc()
821 || gch->incremental_collection_failed();
822 }
823
824
825 //
826 // MarkSweepPolicy methods
827 //
828
829 MarkSweepPolicy::MarkSweepPolicy() {
830 initialize_all();
831 }
832
833 void MarkSweepPolicy::initialize_generations() {
834 _generations = NEW_C_HEAP_ARRAY3(GenerationSpecPtr, number_of_generations(), mtGC, 0, AllocFailStrategy::RETURN_NULL);
835 if (_generations == NULL) {
836 vm_exit_during_initialization("Unable to allocate gen spec");
837 }
838
839 if (UseParNewGC) {
840 _generations[0] = new GenerationSpec(Generation::ParNew, _initial_gen0_size, _max_gen0_size);
841 } else {
842 _generations[0] = new GenerationSpec(Generation::DefNew, _initial_gen0_size, _max_gen0_size);
843 }
844 _generations[1] = new GenerationSpec(Generation::MarkSweepCompact, _initial_gen1_size, _max_gen1_size);
845
846 if (_generations[0] == NULL || _generations[1] == NULL) {
847 vm_exit_during_initialization("Unable to allocate gen spec");
848 }
849 }
850
851 void MarkSweepPolicy::initialize_gc_policy_counters() {
852 // initialize the policy counters - 2 collectors, 3 generations
|
30 #include "memory/collectorPolicy.hpp"
31 #include "memory/gcLocker.inline.hpp"
32 #include "memory/genCollectedHeap.hpp"
33 #include "memory/generationSpec.hpp"
34 #include "memory/space.hpp"
35 #include "memory/universe.hpp"
36 #include "runtime/arguments.hpp"
37 #include "runtime/globals_extension.hpp"
38 #include "runtime/handles.inline.hpp"
39 #include "runtime/java.hpp"
40 #include "runtime/thread.inline.hpp"
41 #include "runtime/vmThread.hpp"
42 #include "utilities/macros.hpp"
43 #if INCLUDE_ALL_GCS
44 #include "gc_implementation/concurrentMarkSweep/cmsAdaptiveSizePolicy.hpp"
45 #include "gc_implementation/concurrentMarkSweep/cmsGCAdaptivePolicyCounters.hpp"
46 #endif // INCLUDE_ALL_GCS
47
48 // CollectorPolicy methods.
49
50 CollectorPolicy::CollectorPolicy() :
51 _space_alignment(0),
52 _heap_alignment(0),
53 _initial_heap_byte_size(InitialHeapSize),
54 _max_heap_byte_size(MaxHeapSize),
55 _min_heap_byte_size(Arguments::min_heap_size()),
56 _max_heap_size_cmdline(false),
57 _size_policy(NULL),
58 _should_clear_all_soft_refs(false),
59 _all_soft_refs_clear(false)
60 {}
61
62 void CollectorPolicy::assert_flags() {
63 assert(InitialHeapSize <= MaxHeapSize, "Ergonomics decided on incompatible initial and maximum heap sizes");
64 assert(InitialHeapSize % _heap_alignment == 0, "InitialHeapSize alignment");
65 assert(MaxHeapSize % _heap_alignment == 0, "MaxHeapSize alignment");
66 }
67
68 void CollectorPolicy::assert_size_info() {
69 assert(InitialHeapSize == _initial_heap_byte_size, "Discrepancy between InitialHeapSize flag and local storage");
70 assert(MaxHeapSize == _max_heap_byte_size, "Discrepancy between MaxHeapSize flag and local storage");
71 assert(_max_heap_byte_size >= _min_heap_byte_size, "Ergonomics decided on incompatible minimum and maximum heap sizes");
72 assert(_initial_heap_byte_size >= _min_heap_byte_size, "Ergonomics decided on incompatible initial and minimum heap sizes");
73 assert(_max_heap_byte_size >= _initial_heap_byte_size, "Ergonomics decided on incompatible initial and maximum heap sizes");
74 assert(_min_heap_byte_size % _heap_alignment == 0, "min_heap_byte_size alignment");
75 assert(_initial_heap_byte_size % _heap_alignment == 0, "initial_heap_byte_size alignment");
76 assert(_max_heap_byte_size % _heap_alignment == 0, "max_heap_byte_size alignment");
77 }
78
79 void CollectorPolicy::initialize_alignments() {
80 _space_alignment = (uintx) Generation::GenGrain;
81 _heap_alignment = compute_heap_alignment();
82 }
83
84 void CollectorPolicy::initialize_flags() {
85 assert(_space_alignment != 0, "Space alignment not set up properly");
86 assert(_heap_alignment != 0, "Heap alignment not set up properly");
87 assert(_heap_alignment >= _space_alignment,
88 err_msg("heap_alignment: " SIZE_FORMAT " less than space_alignment: " SIZE_FORMAT,
89 _heap_alignment, _space_alignment));
90 assert(_heap_alignment % _space_alignment == 0,
91 err_msg("heap_alignment: " SIZE_FORMAT " not aligned by space_alignment: " SIZE_FORMAT,
92 _heap_alignment, _space_alignment));
93
94 if (FLAG_IS_CMDLINE(MaxHeapSize)) {
95 if (FLAG_IS_CMDLINE(InitialHeapSize) && InitialHeapSize > MaxHeapSize) {
96 vm_exit_during_initialization("Initial heap size set to a larger value than the maximum heap size");
97 }
98 if (_min_heap_byte_size != 0 && MaxHeapSize < _min_heap_byte_size) {
99 vm_exit_during_initialization("Incompatible minimum and maximum heap sizes specified");
100 }
101 _max_heap_size_cmdline = true;
102 }
103
104 // Check heap parameter properties
105 if (InitialHeapSize < M) {
106 vm_exit_during_initialization("Too small initial heap");
107 }
108 if (_min_heap_byte_size < M) {
109 vm_exit_during_initialization("Too small minimum heap");
110 }
111
112 // User inputs from -Xmx and -Xms must be aligned
113 _min_heap_byte_size = align_size_up(_min_heap_byte_size, _heap_alignment);
114 uintx alignedInitialHeapSize = align_size_up(InitialHeapSize, _heap_alignment);
115 uintx alignedMaxHeapSize = align_size_up(MaxHeapSize, _heap_alignment);
116
117 // Write back to flags if the values changed
118 if (alignedInitialHeapSize != InitialHeapSize) {
119 FLAG_SET_ERGO(uintx, InitialHeapSize, alignedInitialHeapSize);
120 }
121 if (alignedMaxHeapSize != MaxHeapSize) {
122 FLAG_SET_ERGO(uintx, MaxHeapSize, alignedMaxHeapSize);
123 }
124
125 if (FLAG_IS_CMDLINE(InitialHeapSize) && _min_heap_byte_size != 0 &&
126 InitialHeapSize < _min_heap_byte_size) {
127 vm_exit_during_initialization("Incompatible minimum and initial heap sizes specified");
128 }
129 if (!FLAG_IS_DEFAULT(InitialHeapSize) && InitialHeapSize > MaxHeapSize) {
130 FLAG_SET_ERGO(uintx, MaxHeapSize, InitialHeapSize);
131 } else if (!FLAG_IS_DEFAULT(MaxHeapSize) && InitialHeapSize > MaxHeapSize) {
132 FLAG_SET_ERGO(uintx, InitialHeapSize, MaxHeapSize);
133 if (InitialHeapSize < _min_heap_byte_size) {
134 _min_heap_byte_size = InitialHeapSize;
135 }
136 }
137
138 _initial_heap_byte_size = InitialHeapSize;
139 _max_heap_byte_size = MaxHeapSize;
140
141 FLAG_SET_ERGO(uintx, MinHeapDeltaBytes, align_size_up(MinHeapDeltaBytes, _space_alignment));
142
143 CollectorPolicy::assert_flags();
144 }
145
146 void CollectorPolicy::initialize_size_info() {
147 if (PrintGCDetails && Verbose) {
148 gclog_or_tty->print_cr("Minimum heap " SIZE_FORMAT " Initial heap "
149 SIZE_FORMAT " Maximum heap " SIZE_FORMAT,
150 _min_heap_byte_size, _initial_heap_byte_size, _max_heap_byte_size);
151 }
152
153 CollectorPolicy::assert_size_info();
154 }
155
156 bool CollectorPolicy::use_should_clear_all_soft_refs(bool v) {
157 bool result = _should_clear_all_soft_refs;
158 set_should_clear_all_soft_refs(false);
159 return result;
160 }
161
162 GenRemSet* CollectorPolicy::create_rem_set(MemRegion whole_heap,
163 int max_covered_regions) {
164 return new CardTableRS(whole_heap, max_covered_regions);
165 }
166
167 void CollectorPolicy::cleared_all_soft_refs() {
168 // If near gc overhear limit, continue to clear SoftRefs. SoftRefs may
169 // have been cleared in the last collection but if the gc overhear
170 // limit continues to be near, SoftRefs should still be cleared.
171 if (size_policy() != NULL) {
172 _should_clear_all_soft_refs = size_policy()->gc_overhead_limit_near();
173 }
174 _all_soft_refs_clear = true;
175 }
176
177 size_t CollectorPolicy::compute_heap_alignment() {
178 // The card marking array and the offset arrays for old generations are
179 // committed in os pages as well. Make sure they are entirely full (to
180 // avoid partial page problems), e.g. if 512 bytes heap corresponds to 1
181 // byte entry and the os page size is 4096, the maximum heap size should
182 // be 512*4096 = 2MB aligned.
183
184 // There is only the GenRemSet in Hotspot and only the GenRemSet::CardTable
185 // is supported.
186 // Requirements of any new remembered set implementations must be added here.
187 size_t alignment = GenRemSet::max_alignment_constraint(GenRemSet::CardTable);
188
189 // Parallel GC does its own alignment of the generations to avoid requiring a
190 // large page (256M on some platforms) for the permanent generation. The
191 // other collectors should also be updated to do their own alignment and then
192 // this use of lcm() should be removed.
193 if (UseLargePages && !UseParallelGC) {
194 // in presence of large pages we have to make sure that our
195 // alignment is large page aware
196 alignment = lcm(os::large_page_size(), alignment);
197 }
198
199 return alignment;
200 }
201
202 // GenCollectorPolicy methods.
203
204 size_t GenCollectorPolicy::scale_by_NewRatio_aligned(size_t base_size) {
205 return align_size_down_bounded(base_size / (NewRatio + 1), _gen_alignment);
206 }
207
208 size_t GenCollectorPolicy::bound_minus_alignment(size_t desired_size,
209 size_t maximum_size) {
210 size_t max_minus = maximum_size - _gen_alignment;
211 return desired_size < max_minus ? desired_size : max_minus;
212 }
213
214
215 void GenCollectorPolicy::initialize_size_policy(size_t init_eden_size,
216 size_t init_promo_size,
217 size_t init_survivor_size) {
218 const double max_gc_pause_sec = ((double) MaxGCPauseMillis) / 1000.0;
219 _size_policy = new AdaptiveSizePolicy(init_eden_size,
220 init_promo_size,
221 init_survivor_size,
222 max_gc_pause_sec,
223 GCTimeRatio);
224 }
225
226 size_t GenCollectorPolicy::young_gen_size_lower_bound() {
227 // The young generation must be aligned and have room for eden + two survivors
228 return align_size_up(3 * _space_alignment, _gen_alignment);
229 }
230
231 void GenCollectorPolicy::assert_flags() {
232 CollectorPolicy::assert_flags();
233 assert(NewSize >= _min_gen0_size, "Ergonomics decided on a too small young gen size");
234 assert(NewSize <= MaxNewSize, "Ergonomics decided on incompatible initial and maximum young gen sizes");
235 assert(FLAG_IS_DEFAULT(MaxNewSize) || MaxNewSize < MaxHeapSize, "Ergonomics decided on incompatible maximum young gen and heap sizes");
236 assert(NewSize % _gen_alignment == 0, "NewSize alignment");
237 assert(FLAG_IS_DEFAULT(MaxNewSize) || MaxNewSize % _gen_alignment == 0, "MaxNewSize alignment");
238 }
239
240 void TwoGenerationCollectorPolicy::assert_flags() {
241 GenCollectorPolicy::assert_flags();
242 assert(OldSize + NewSize <= MaxHeapSize, "Ergonomics decided on incompatible generation and heap sizes");
243 assert(OldSize % _gen_alignment == 0, "OldSize alignment");
244 }
245
246 void GenCollectorPolicy::assert_size_info() {
247 CollectorPolicy::assert_size_info();
248 // GenCollectorPolicy::initialize_size_info may update the MaxNewSize
249 assert(MaxNewSize < MaxHeapSize, "Ergonomics decided on incompatible maximum young and heap sizes");
250 assert(NewSize == _initial_gen0_size, "Discrepancy between NewSize flag and local storage");
251 assert(MaxNewSize == _max_gen0_size, "Discrepancy between MaxNewSize flag and local storage");
252 assert(_min_gen0_size <= _initial_gen0_size, "Ergonomics decided on incompatible minimum and initial young gen sizes");
253 assert(_initial_gen0_size <= _max_gen0_size, "Ergonomics decided on incompatible initial and maximum young gen sizes");
254 assert(_min_gen0_size % _gen_alignment == 0, "_min_gen0_size alignment");
255 assert(_initial_gen0_size % _gen_alignment == 0, "_initial_gen0_size alignment");
256 assert(_max_gen0_size % _gen_alignment == 0, "_max_gen0_size alignment");
257 }
258
259 void TwoGenerationCollectorPolicy::assert_size_info() {
260 GenCollectorPolicy::assert_size_info();
261 assert(OldSize == _initial_gen1_size, "Discrepancy between OldSize flag and local storage");
262 assert(_min_gen1_size <= _initial_gen1_size, "Ergonomics decided on incompatible minimum and initial old gen sizes");
263 assert(_initial_gen1_size <= _max_gen1_size, "Ergonomics decided on incompatible initial and maximum old gen sizes");
264 assert(_max_gen1_size % _gen_alignment == 0, "_max_gen1_size alignment");
265 assert(_initial_gen1_size % _gen_alignment == 0, "_initial_gen1_size alignment");
266 assert(_max_heap_byte_size <= (_max_gen0_size + _max_gen1_size), "Total maximum heap sizes must be sum of generation maximum sizes");
267 }
268
269 void GenCollectorPolicy::initialize_alignments() {
270 CollectorPolicy::initialize_alignments();
271 _gen_alignment = default_gen_alignment();
272 }
273
274 void GenCollectorPolicy::initialize_flags() {
275 CollectorPolicy::initialize_flags();
276
277 assert(_gen_alignment != 0, "Generation alignment not set up properly");
278 assert(_heap_alignment >= _gen_alignment,
279 err_msg("heap_alignment: " SIZE_FORMAT " less than gen_alignment: " SIZE_FORMAT,
280 _heap_alignment, _gen_alignment));
281 assert(_gen_alignment % _space_alignment == 0,
282 err_msg("gen_alignment: " SIZE_FORMAT " not aligned by space_alignment: " SIZE_FORMAT,
283 _gen_alignment, _space_alignment));
284
285 // All generational heaps have a youngest gen; handle those flags here
286 if (FLAG_IS_CMDLINE(NewSize) && FLAG_IS_CMDLINE(MaxNewSize) && NewSize > MaxNewSize) {
287 vm_exit_during_initialization("Initial young gen size set larger than the maximum young gen size");
288 }
289
290 // Make sure the heap is large enough for two generations
291 uintx smallestNewSize = young_gen_size_lower_bound();
292 uintx smallestHeapSize = align_size_up(smallestNewSize + align_size_up(_space_alignment, _gen_alignment),
293 _heap_alignment);
294 if (MaxHeapSize < smallestHeapSize) {
295 FLAG_SET_ERGO(uintx, MaxHeapSize, smallestHeapSize);
296 _max_heap_byte_size = MaxHeapSize;
297 }
298 // If needed, synchronize _min_heap_byte size and _initial_heap_byte_size
299 if (_min_heap_byte_size < smallestHeapSize) {
300 _min_heap_byte_size = smallestHeapSize;
301 if (InitialHeapSize < _min_heap_byte_size) {
302 FLAG_SET_ERGO(uintx, InitialHeapSize, smallestHeapSize);
303 _initial_heap_byte_size = smallestHeapSize;
304 }
305 }
306
307 // Now take the actual NewSize into account. We will silently increase NewSize
308 // if the user specified a smaller value.
309 smallestNewSize = MAX2(smallestNewSize, (uintx)align_size_down(NewSize, _gen_alignment));
310 if (smallestNewSize != NewSize) {
311 FLAG_SET_ERGO(uintx, NewSize, smallestNewSize);
312 }
313 _initial_gen0_size = NewSize;
314
315 if (!FLAG_IS_DEFAULT(MaxNewSize)) {
316 uintx minNewSize = MAX2(_gen_alignment, _min_gen0_size);
317
318 if (MaxNewSize >= MaxHeapSize) {
319 // Make sure there is room for an old generation
320 uintx smallerMaxNewSize = MaxHeapSize - _gen_alignment;
321 if (FLAG_IS_CMDLINE(MaxNewSize)) {
322 warning("MaxNewSize (" SIZE_FORMAT "k) is equal to or greater than the entire "
323 "heap (" SIZE_FORMAT "k). A new max generation size of " SIZE_FORMAT "k will be used.",
324 MaxNewSize/K, MaxHeapSize/K, smallerMaxNewSize/K);
325 }
326 FLAG_SET_ERGO(uintx, MaxNewSize, smallerMaxNewSize);
327 if (NewSize > MaxNewSize) {
328 FLAG_SET_ERGO(uintx, NewSize, MaxNewSize);
329 _initial_gen0_size = NewSize;
330 }
331 } else if (MaxNewSize < minNewSize) {
332 FLAG_SET_ERGO(uintx, MaxNewSize, minNewSize);
333 } else if (!is_size_aligned(MaxNewSize, _gen_alignment)) {
334 FLAG_SET_ERGO(uintx, MaxNewSize, align_size_down(MaxNewSize, _gen_alignment));
335 }
336 _max_gen0_size = MaxNewSize;
337 }
338
339 if (NewSize > MaxNewSize) {
340 // At this point this should only happen if the user specifies a large NewSize or
341 // a small (but not too small) MaxNewSize.
342 if (FLAG_IS_CMDLINE(NewSize)) {
343 warning("NewSize (" SIZE_FORMAT "k) is greater than the MaxNewSize (" SIZE_FORMAT "k). "
344 "A new generation size of " SIZE_FORMAT "k will be used.",
345 NewSize/K, MaxNewSize/K, MaxNewSize/K);
346 }
347 FLAG_SET_ERGO(uintx, NewSize, MaxNewSize);
348 _initial_gen0_size = NewSize;
349 }
350
351 if (SurvivorRatio < 1 || NewRatio < 1) {
352 vm_exit_during_initialization("Invalid young gen ratio specified");
353 }
354
355 GenCollectorPolicy::assert_flags();
356 }
357
358 void TwoGenerationCollectorPolicy::initialize_flags() {
359 GenCollectorPolicy::initialize_flags();
360
361 if (!is_size_aligned(OldSize, _gen_alignment)) {
362 FLAG_SET_ERGO(uintx, OldSize, align_size_down(OldSize, _gen_alignment));
363 }
364
365 if (FLAG_IS_CMDLINE(OldSize) && FLAG_IS_DEFAULT(MaxHeapSize)) {
366 // NewRatio will be used later to set the young generation size so we use
367 // it to calculate how big the heap should be based on the requested OldSize
368 // and NewRatio.
369 assert(NewRatio > 0, "NewRatio should have been set up earlier");
370 size_t calculated_heapsize = (OldSize / NewRatio) * (NewRatio + 1);
371
372 calculated_heapsize = align_size_up(calculated_heapsize, _heap_alignment);
373 FLAG_SET_ERGO(uintx, MaxHeapSize, calculated_heapsize);
374 _max_heap_byte_size = MaxHeapSize;
375 FLAG_SET_ERGO(uintx, InitialHeapSize, calculated_heapsize);
376 _initial_heap_byte_size = InitialHeapSize;
377 }
378
379 // adjust max heap size if necessary
380 if (NewSize + OldSize > MaxHeapSize) {
381 if (_max_heap_size_cmdline) {
382 // somebody set a maximum heap size with the intention that we should not
383 // exceed it. Adjust New/OldSize as necessary.
384 uintx calculated_size = NewSize + OldSize;
385 double shrink_factor = (double) MaxHeapSize / calculated_size;
386 uintx smallerNewSize = align_size_down((uintx)(NewSize * shrink_factor), _gen_alignment);
387 FLAG_SET_ERGO(uintx, NewSize, MAX2(young_gen_size_lower_bound(), smallerNewSize));
388 _initial_gen0_size = NewSize;
389
390 // OldSize is already aligned because above we aligned MaxHeapSize to
391 // _heap_alignment, and we just made sure that NewSize is aligned to
392 // _gen_alignment. In initialize_flags() we verified that _heap_alignment
393 // is a multiple of _gen_alignment.
394 FLAG_SET_ERGO(uintx, OldSize, MaxHeapSize - NewSize);
395 } else {
396 FLAG_SET_ERGO(uintx, MaxHeapSize, align_size_up(NewSize + OldSize, _heap_alignment));
397 _max_heap_byte_size = MaxHeapSize;
398 }
399 }
400
401 always_do_update_barrier = UseConcMarkSweepGC;
402 TwoGenerationCollectorPolicy::assert_flags();
403 }
404
405 // Values set on the command line win over any ergonomically
406 // set command line parameters.
407 // Ergonomic choice of parameters are done before this
408 // method is called. Values for command line parameters such as NewSize
409 // and MaxNewSize feed those ergonomic choices into this method.
410 // This method makes the final generation sizings consistent with
411 // themselves and with overall heap sizings.
412 // In the absence of explicitly set command line flags, policies
413 // such as the use of NewRatio are used to size the generation.
414 void GenCollectorPolicy::initialize_size_info() {
415 CollectorPolicy::initialize_size_info();
416
417 // _space_alignment is used for alignment within a generation.
418 // There is additional alignment done down stream for some
419 // collectors that sometimes causes unwanted rounding up of
420 // generations sizes.
421
422 // Determine maximum size of gen0
423
424 size_t max_new_size = 0;
425 if (!FLAG_IS_DEFAULT(MaxNewSize)) {
426 max_new_size = MaxNewSize;
427 } else {
428 max_new_size = scale_by_NewRatio_aligned(_max_heap_byte_size);
429 // Bound the maximum size by NewSize below (since it historically
430 // would have been NewSize and because the NewRatio calculation could
431 // yield a size that is too small) and bound it by MaxNewSize above.
432 // Ergonomics plays here by previously calculating the desired
433 // NewSize and MaxNewSize.
434 max_new_size = MIN2(MAX2(max_new_size, NewSize), MaxNewSize);
435 }
436 assert(max_new_size > 0, "All paths should set max_new_size");
437
438 // Given the maximum gen0 size, determine the initial and
439 // minimum gen0 sizes.
440
441 if (_max_heap_byte_size == _min_heap_byte_size) {
442 // The maximum and minimum heap sizes are the same so
443 // the generations minimum and initial must be the
444 // same as its maximum.
445 _min_gen0_size = max_new_size;
446 _initial_gen0_size = max_new_size;
475 _max_gen0_size = max_new_size;
476
477 // At this point the desirable initial and minimum sizes have been
478 // determined without regard to the maximum sizes.
479
480 // Bound the sizes by the corresponding overall heap sizes.
481 _min_gen0_size = bound_minus_alignment(_min_gen0_size, _min_heap_byte_size);
482 _initial_gen0_size = bound_minus_alignment(_initial_gen0_size, _initial_heap_byte_size);
483 _max_gen0_size = bound_minus_alignment(_max_gen0_size, _max_heap_byte_size);
484
485 // At this point all three sizes have been checked against the
486 // maximum sizes but have not been checked for consistency
487 // among the three.
488
489 // Final check min <= initial <= max
490 _min_gen0_size = MIN2(_min_gen0_size, _max_gen0_size);
491 _initial_gen0_size = MAX2(MIN2(_initial_gen0_size, _max_gen0_size), _min_gen0_size);
492 _min_gen0_size = MIN2(_min_gen0_size, _initial_gen0_size);
493 }
494
495 // Write back to flags if necessary
496 if (NewSize != _initial_gen0_size) {
497 FLAG_SET_ERGO(uintx, NewSize, _initial_gen0_size);
498 }
499
500 if (MaxNewSize != _max_gen0_size) {
501 FLAG_SET_ERGO(uintx, MaxNewSize, _max_gen0_size);
502 }
503
504 if (PrintGCDetails && Verbose) {
505 gclog_or_tty->print_cr("1: Minimum gen0 " SIZE_FORMAT " Initial gen0 "
506 SIZE_FORMAT " Maximum gen0 " SIZE_FORMAT,
507 _min_gen0_size, _initial_gen0_size, _max_gen0_size);
508 }
509
510 GenCollectorPolicy::assert_size_info();
511 }
512
513 // Call this method during the sizing of the gen1 to make
514 // adjustments to gen0 because of gen1 sizing policy. gen0 initially has
515 // the most freedom in sizing because it is done before the
516 // policy for gen1 is applied. Once gen1 policies have been applied,
517 // there may be conflicts in the shape of the heap and this method
518 // is used to make the needed adjustments. The application of the
519 // policies could be more sophisticated (iterative for example) but
520 // keeping it simple also seems a worthwhile goal.
521 bool TwoGenerationCollectorPolicy::adjust_gen0_sizes(size_t* gen0_size_ptr,
522 size_t* gen1_size_ptr,
523 const size_t heap_size,
524 const size_t min_gen1_size) {
525 bool result = false;
526
527 if ((*gen1_size_ptr + *gen0_size_ptr) > heap_size) {
528 uintx smallestNewSize = young_gen_size_lower_bound();
529 if ((heap_size < (*gen0_size_ptr + min_gen1_size)) &&
530 (heap_size >= min_gen1_size + smallestNewSize)) {
531 // Adjust gen0 down to accommodate min_gen1_size
532 *gen0_size_ptr = align_size_down_bounded(heap_size - min_gen1_size, _gen_alignment);
533 assert(*gen0_size_ptr > 0, "Min gen0 is too large");
534 result = true;
535 } else {
536 *gen1_size_ptr = align_size_down_bounded(heap_size - *gen0_size_ptr, _gen_alignment);
537 }
538 }
539 return result;
540 }
541
542 // Minimum sizes of the generations may be different than
543 // the initial sizes. An inconsistently is permitted here
544 // in the total size that can be specified explicitly by
545 // command line specification of OldSize and NewSize and
546 // also a command line specification of -Xms. Issue a warning
547 // but allow the values to pass.
548
549 void TwoGenerationCollectorPolicy::initialize_size_info() {
550 GenCollectorPolicy::initialize_size_info();
551
552 // At this point the minimum, initial and maximum sizes
553 // of the overall heap and of gen0 have been determined.
554 // The maximum gen1 size can be determined from the maximum gen0
555 // and maximum heap size since no explicit flags exits
556 // for setting the gen1 maximum.
557 _max_gen1_size = MAX2(_max_heap_byte_size - _max_gen0_size, _gen_alignment);
558
559 // If no explicit command line flag has been set for the
560 // gen1 size, use what is left for gen1.
561 if (!FLAG_IS_CMDLINE(OldSize)) {
562 // The user has not specified any value but the ergonomics
563 // may have chosen a value (which may or may not be consistent
564 // with the overall heap size). In either case make
565 // the minimum, maximum and initial sizes consistent
566 // with the gen0 sizes and the overall heap sizes.
567 _min_gen1_size = MAX2(_min_heap_byte_size - _min_gen0_size, _gen_alignment);
568 _initial_gen1_size = MAX2(_initial_heap_byte_size - _initial_gen0_size, _gen_alignment);
569 // _max_gen1_size has already been made consistent above
570 FLAG_SET_ERGO(uintx, OldSize, _initial_gen1_size);
571 } else {
572 // It's been explicitly set on the command line. Use the
573 // OldSize and then determine the consequences.
574 _min_gen1_size = MIN2(OldSize, _min_heap_byte_size - _min_gen0_size);
575 _initial_gen1_size = OldSize;
576
577 // If the user has explicitly set an OldSize that is inconsistent
578 // with other command line flags, issue a warning.
579 // The generation minimums and the overall heap mimimum should
580 // be within one generation alignment.
581 if ((_min_gen1_size + _min_gen0_size + _gen_alignment) < _min_heap_byte_size) {
582 warning("Inconsistency between minimum heap size and minimum "
583 "generation sizes: using minimum heap = " SIZE_FORMAT,
584 _min_heap_byte_size);
585 }
586 if (OldSize > _max_gen1_size) {
587 warning("Inconsistency between maximum heap size and maximum "
588 "generation sizes: using maximum heap = " SIZE_FORMAT
589 " -XX:OldSize flag is being ignored",
590 _max_heap_byte_size);
591 }
592 // If there is an inconsistency between the OldSize and the minimum and/or
593 // initial size of gen0, since OldSize was explicitly set, OldSize wins.
594 if (adjust_gen0_sizes(&_min_gen0_size, &_min_gen1_size,
595 _min_heap_byte_size, _min_gen1_size)) {
596 if (PrintGCDetails && Verbose) {
597 gclog_or_tty->print_cr("2: Minimum gen0 " SIZE_FORMAT " Initial gen0 "
598 SIZE_FORMAT " Maximum gen0 " SIZE_FORMAT,
599 _min_gen0_size, _initial_gen0_size, _max_gen0_size);
600 }
601 }
602 // Initial size
603 if (adjust_gen0_sizes(&_initial_gen0_size, &_initial_gen1_size,
604 _initial_heap_byte_size, _initial_gen1_size)) {
605 if (PrintGCDetails && Verbose) {
606 gclog_or_tty->print_cr("3: Minimum gen0 " SIZE_FORMAT " Initial gen0 "
607 SIZE_FORMAT " Maximum gen0 " SIZE_FORMAT,
608 _min_gen0_size, _initial_gen0_size, _max_gen0_size);
609 }
610 }
611 }
612 // Enforce the maximum gen1 size.
613 _min_gen1_size = MIN2(_min_gen1_size, _max_gen1_size);
614
615 // Check that min gen1 <= initial gen1 <= max gen1
616 _initial_gen1_size = MAX2(_initial_gen1_size, _min_gen1_size);
617 _initial_gen1_size = MIN2(_initial_gen1_size, _max_gen1_size);
618
619 // Write back to flags if necessary
620 if (NewSize != _initial_gen0_size) {
621 FLAG_SET_ERGO(uintx, NewSize, _max_gen0_size);
622 }
623
624 if (MaxNewSize != _max_gen0_size) {
625 FLAG_SET_ERGO(uintx, MaxNewSize, _max_gen0_size);
626 }
627
628 if (OldSize != _initial_gen1_size) {
629 FLAG_SET_ERGO(uintx, OldSize, _initial_gen1_size);
630 }
631
632 if (PrintGCDetails && Verbose) {
633 gclog_or_tty->print_cr("Minimum gen1 " SIZE_FORMAT " Initial gen1 "
634 SIZE_FORMAT " Maximum gen1 " SIZE_FORMAT,
635 _min_gen1_size, _initial_gen1_size, _max_gen1_size);
636 }
637
638 TwoGenerationCollectorPolicy::assert_size_info();
639 }
640
641 HeapWord* GenCollectorPolicy::mem_allocate_work(size_t size,
642 bool is_tlab,
643 bool* gc_overhead_limit_was_exceeded) {
644 GenCollectedHeap *gch = GenCollectedHeap::heap();
645
646 debug_only(gch->check_for_valid_allocation_state());
647 assert(gch->no_gc_in_progress(), "Allocation during gc not allowed");
648
649 // In general gc_overhead_limit_was_exceeded should be false so
650 // set it so here and reset it to true only if the gc time
651 // limit is being exceeded as checked below.
652 *gc_overhead_limit_was_exceeded = false;
653
654 HeapWord* result = NULL;
655
656 // Loop until the allocation is satisified,
657 // or unsatisfied after GC.
658 for (int try_count = 1, gclocker_stalled_count = 0; /* return or throw */; try_count += 1) {
941 // Return true if any of the following is true:
942 // . the allocation won't fit into the current young gen heap
943 // . gc locker is occupied (jni critical section)
944 // . heap memory is tight -- the most recent previous collection
945 // was a full collection because a partial collection (would
946 // have) failed and is likely to fail again
947 bool GenCollectorPolicy::should_try_older_generation_allocation(
948 size_t word_size) const {
949 GenCollectedHeap* gch = GenCollectedHeap::heap();
950 size_t gen0_capacity = gch->get_gen(0)->capacity_before_gc();
951 return (word_size > heap_word_size(gen0_capacity))
952 || GC_locker::is_active_and_needs_gc()
953 || gch->incremental_collection_failed();
954 }
955
956
957 //
958 // MarkSweepPolicy methods
959 //
960
961 void MarkSweepPolicy::initialize_generations() {
962 _generations = NEW_C_HEAP_ARRAY3(GenerationSpecPtr, number_of_generations(), mtGC, 0, AllocFailStrategy::RETURN_NULL);
963 if (_generations == NULL) {
964 vm_exit_during_initialization("Unable to allocate gen spec");
965 }
966
967 if (UseParNewGC) {
968 _generations[0] = new GenerationSpec(Generation::ParNew, _initial_gen0_size, _max_gen0_size);
969 } else {
970 _generations[0] = new GenerationSpec(Generation::DefNew, _initial_gen0_size, _max_gen0_size);
971 }
972 _generations[1] = new GenerationSpec(Generation::MarkSweepCompact, _initial_gen1_size, _max_gen1_size);
973
974 if (_generations[0] == NULL || _generations[1] == NULL) {
975 vm_exit_during_initialization("Unable to allocate gen spec");
976 }
977 }
978
979 void MarkSweepPolicy::initialize_gc_policy_counters() {
980 // initialize the policy counters - 2 collectors, 3 generations
|