1 #ifdef USE_PRAGMA_IDENT_SRC
2 #pragma ident "@(#)parallelScavengeHeap.cpp 1.95 07/10/04 10:49:31 JVM"
3 #endif
4 /*
5 * Copyright 2001-2007 Sun Microsystems, Inc. All Rights Reserved.
6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
7 *
8 * This code is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 only, as
10 * published by the Free Software Foundation.
11 *
12 * This code is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 * version 2 for more details (a copy is included in the LICENSE file that
16 * accompanied this code).
17 *
18 * You should have received a copy of the GNU General Public License version
19 * 2 along with this work; if not, write to the Free Software Foundation,
20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
21 *
22 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
23 * CA 95054 USA or visit www.sun.com if you need additional information or
24 * have any questions.
25 *
26 */
27
28 # include "incls/_precompiled.incl"
29 # include "incls/_parallelScavengeHeap.cpp.incl"
30
31 PSYoungGen* ParallelScavengeHeap::_young_gen = NULL;
32 PSOldGen* ParallelScavengeHeap::_old_gen = NULL;
33 PSPermGen* ParallelScavengeHeap::_perm_gen = NULL;
34 PSAdaptiveSizePolicy* ParallelScavengeHeap::_size_policy = NULL;
35 PSGCAdaptivePolicyCounters* ParallelScavengeHeap::_gc_policy_counters = NULL;
36 ParallelScavengeHeap* ParallelScavengeHeap::_psh = NULL;
37 GCTaskManager* ParallelScavengeHeap::_gc_task_manager = NULL;
38
39 static void trace_gen_sizes(const char* const str,
40 size_t pg_min, size_t pg_max,
41 size_t og_min, size_t og_max,
42 size_t yg_min, size_t yg_max)
43 {
44 if (TracePageSizes) {
45 tty->print_cr("%s: " SIZE_FORMAT "," SIZE_FORMAT " "
46 SIZE_FORMAT "," SIZE_FORMAT " "
47 SIZE_FORMAT "," SIZE_FORMAT " "
48 SIZE_FORMAT,
49 str, pg_min / K, pg_max / K,
50 og_min / K, og_max / K,
51 yg_min / K, yg_max / K,
52 (pg_max + og_max + yg_max) / K);
53 }
54 }
55
56 jint ParallelScavengeHeap::initialize() {
57 // Cannot be initialized until after the flags are parsed
58 GenerationSizer flag_parser;
59
60 size_t yg_min_size = flag_parser.min_young_gen_size();
61 size_t yg_max_size = flag_parser.max_young_gen_size();
62 size_t og_min_size = flag_parser.min_old_gen_size();
63 size_t og_max_size = flag_parser.max_old_gen_size();
64 // Why isn't there a min_perm_gen_size()?
65 size_t pg_min_size = flag_parser.perm_gen_size();
66 size_t pg_max_size = flag_parser.max_perm_gen_size();
67
68 trace_gen_sizes("ps heap raw",
69 pg_min_size, pg_max_size,
70 og_min_size, og_max_size,
71 yg_min_size, yg_max_size);
72
73 // The ReservedSpace ctor used below requires that the page size for the perm
74 // gen is <= the page size for the rest of the heap (young + old gens).
75 const size_t og_page_sz = os::page_size_for_region(yg_min_size + og_min_size,
76 yg_max_size + og_max_size,
77 8);
78 const size_t pg_page_sz = MIN2(os::page_size_for_region(pg_min_size,
79 pg_max_size, 16),
80 og_page_sz);
81
82 const size_t pg_align = set_alignment(_perm_gen_alignment, pg_page_sz);
83 const size_t og_align = set_alignment(_old_gen_alignment, og_page_sz);
84 const size_t yg_align = set_alignment(_young_gen_alignment, og_page_sz);
85
86 // Update sizes to reflect the selected page size(s).
87 //
88 // NEEDS_CLEANUP. The default TwoGenerationCollectorPolicy uses NewRatio; it
89 // should check UseAdaptiveSizePolicy. Changes from generationSizer could
90 // move to the common code.
91 yg_min_size = align_size_up(yg_min_size, yg_align);
92 yg_max_size = align_size_up(yg_max_size, yg_align);
93 size_t yg_cur_size = align_size_up(flag_parser.young_gen_size(), yg_align);
94 yg_cur_size = MAX2(yg_cur_size, yg_min_size);
95
96 og_min_size = align_size_up(og_min_size, og_align);
97 og_max_size = align_size_up(og_max_size, og_align);
98 size_t og_cur_size = align_size_up(flag_parser.old_gen_size(), og_align);
99 og_cur_size = MAX2(og_cur_size, og_min_size);
100
101 pg_min_size = align_size_up(pg_min_size, pg_align);
102 pg_max_size = align_size_up(pg_max_size, pg_align);
103 size_t pg_cur_size = pg_min_size;
104
105 trace_gen_sizes("ps heap rnd",
106 pg_min_size, pg_max_size,
107 og_min_size, og_max_size,
108 yg_min_size, yg_max_size);
109
110 // The main part of the heap (old gen + young gen) can often use a larger page
111 // size than is needed or wanted for the perm gen. Use the "compound
112 // alignment" ReservedSpace ctor to avoid having to use the same page size for
113 // all gens.
114 ReservedSpace heap_rs(pg_max_size, pg_align, og_max_size + yg_max_size,
115 og_align);
116 os::trace_page_sizes("ps perm", pg_min_size, pg_max_size, pg_page_sz,
117 heap_rs.base(), pg_max_size);
118 os::trace_page_sizes("ps main", og_min_size + yg_min_size,
119 og_max_size + yg_max_size, og_page_sz,
120 heap_rs.base() + pg_max_size,
121 heap_rs.size() - pg_max_size);
122 if (!heap_rs.is_reserved()) {
123 vm_shutdown_during_initialization(
124 "Could not reserve enough space for object heap");
125 return JNI_ENOMEM;
126 }
127
128 _reserved = MemRegion((HeapWord*)heap_rs.base(),
129 (HeapWord*)(heap_rs.base() + heap_rs.size()));
130
131 CardTableExtension* const barrier_set = new CardTableExtension(_reserved, 3);
132 _barrier_set = barrier_set;
133 oopDesc::set_bs(_barrier_set);
134 if (_barrier_set == NULL) {
135 vm_shutdown_during_initialization(
136 "Could not reserve enough space for barrier set");
137 return JNI_ENOMEM;
138 }
139
140 // Initial young gen size is 4 Mb
141 //
142 // XXX - what about flag_parser.young_gen_size()?
143 const size_t init_young_size = align_size_up(4 * M, yg_align);
144 yg_cur_size = MAX2(MIN2(init_young_size, yg_max_size), yg_cur_size);
145
146 // Split the reserved space into perm gen and the main heap (everything else).
147 // The main heap uses a different alignment.
148 ReservedSpace perm_rs = heap_rs.first_part(pg_max_size);
149 ReservedSpace main_rs = heap_rs.last_part(pg_max_size, og_align);
150
151 // Make up the generations
152 // Calculate the maximum size that a generation can grow. This
153 // includes growth into the other generation. Note that the
154 // parameter _max_gen_size is kept as the maximum
155 // size of the generation as the boundaries currently stand.
156 // _max_gen_size is still used as that value.
157 double max_gc_pause_sec = ((double) MaxGCPauseMillis)/1000.0;
158 double max_gc_minor_pause_sec = ((double) MaxGCMinorPauseMillis)/1000.0;
159
160 _gens = new AdjoiningGenerations(main_rs,
161 og_cur_size,
162 og_min_size,
163 og_max_size,
164 yg_cur_size,
165 yg_min_size,
166 yg_max_size,
167 yg_align);
168
169 _old_gen = _gens->old_gen();
170 _young_gen = _gens->young_gen();
171
172 const size_t eden_capacity = _young_gen->eden_space()->capacity_in_bytes();
173 const size_t old_capacity = _old_gen->capacity_in_bytes();
174 const size_t initial_promo_size = MIN2(eden_capacity, old_capacity);
175 _size_policy =
176 new PSAdaptiveSizePolicy(eden_capacity,
177 initial_promo_size,
178 young_gen()->to_space()->capacity_in_bytes(),
179 intra_generation_alignment(),
180 max_gc_pause_sec,
181 max_gc_minor_pause_sec,
182 GCTimeRatio
183 );
184
185 _perm_gen = new PSPermGen(perm_rs,
186 pg_align,
187 pg_cur_size,
188 pg_cur_size,
189 pg_max_size,
190 "perm", 2);
191
192 assert(!UseAdaptiveGCBoundary ||
193 (old_gen()->virtual_space()->high_boundary() ==
194 young_gen()->virtual_space()->low_boundary()),
195 "Boundaries must meet");
196 // initialize the policy counters - 2 collectors, 3 generations
197 _gc_policy_counters =
198 new PSGCAdaptivePolicyCounters("ParScav:MSC", 2, 3, _size_policy);
199 _psh = this;
200
201 // Set up the GCTaskManager
202 _gc_task_manager = GCTaskManager::create(ParallelGCThreads);
203
204 if (UseParallelOldGC && !PSParallelCompact::initialize()) {
205 return JNI_ENOMEM;
206 }
207
208 return JNI_OK;
209 }
210
211 void ParallelScavengeHeap::post_initialize() {
212 // Need to init the tenuring threshold
213 PSScavenge::initialize();
214 if (UseParallelOldGC) {
215 PSParallelCompact::post_initialize();
216 if (VerifyParallelOldWithMarkSweep) {
217 // Will be used for verification of par old.
218 PSMarkSweep::initialize();
219 }
220 } else {
221 PSMarkSweep::initialize();
222 }
223 PSPromotionManager::initialize();
224 }
225
226 void ParallelScavengeHeap::update_counters() {
227 young_gen()->update_counters();
228 old_gen()->update_counters();
229 perm_gen()->update_counters();
230 }
231
232 size_t ParallelScavengeHeap::capacity() const {
233 size_t value = young_gen()->capacity_in_bytes() + old_gen()->capacity_in_bytes();
234 return value;
235 }
236
237 size_t ParallelScavengeHeap::used() const {
238 size_t value = young_gen()->used_in_bytes() + old_gen()->used_in_bytes();
239 return value;
240 }
241
242 bool ParallelScavengeHeap::is_maximal_no_gc() const {
243 return old_gen()->is_maximal_no_gc() && young_gen()->is_maximal_no_gc();
244 }
245
246
247 size_t ParallelScavengeHeap::permanent_capacity() const {
248 return perm_gen()->capacity_in_bytes();
249 }
250
251 size_t ParallelScavengeHeap::permanent_used() const {
252 return perm_gen()->used_in_bytes();
253 }
254
255 size_t ParallelScavengeHeap::max_capacity() const {
256 size_t estimated = reserved_region().byte_size();
257 estimated -= perm_gen()->reserved().byte_size();
258 if (UseAdaptiveSizePolicy) {
259 estimated -= _size_policy->max_survivor_size(young_gen()->max_size());
260 } else {
261 estimated -= young_gen()->to_space()->capacity_in_bytes();
262 }
263 return MAX2(estimated, capacity());
264 }
265
266 bool ParallelScavengeHeap::is_in(const void* p) const {
267 if (young_gen()->is_in(p)) {
268 return true;
269 }
270
271 if (old_gen()->is_in(p)) {
272 return true;
273 }
274
275 if (perm_gen()->is_in(p)) {
276 return true;
277 }
278
279 return false;
280 }
281
282 bool ParallelScavengeHeap::is_in_reserved(const void* p) const {
283 if (young_gen()->is_in_reserved(p)) {
284 return true;
285 }
286
287 if (old_gen()->is_in_reserved(p)) {
288 return true;
289 }
290
291 if (perm_gen()->is_in_reserved(p)) {
292 return true;
293 }
294
295 return false;
296 }
297
298 // Static method
299 bool ParallelScavengeHeap::is_in_young(oop* p) {
300 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
301 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap,
302 "Must be ParallelScavengeHeap");
303
304 PSYoungGen* young_gen = heap->young_gen();
305
306 if (young_gen->is_in_reserved(p)) {
307 return true;
308 }
309
310 return false;
311 }
312
313 // Static method
314 bool ParallelScavengeHeap::is_in_old_or_perm(oop* p) {
315 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
316 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap,
317 "Must be ParallelScavengeHeap");
318
319 PSOldGen* old_gen = heap->old_gen();
320 PSPermGen* perm_gen = heap->perm_gen();
321
322 if (old_gen->is_in_reserved(p)) {
323 return true;
324 }
325
326 if (perm_gen->is_in_reserved(p)) {
327 return true;
328 }
329
330 return false;
331 }
332
333 // There are two levels of allocation policy here.
334 //
335 // When an allocation request fails, the requesting thread must invoke a VM
336 // operation, transfer control to the VM thread, and await the results of a
337 // garbage collection. That is quite expensive, and we should avoid doing it
338 // multiple times if possible.
339 //
340 // To accomplish this, we have a basic allocation policy, and also a
341 // failed allocation policy.
342 //
343 // The basic allocation policy controls how you allocate memory without
344 // attempting garbage collection. It is okay to grab locks and
345 // expand the heap, if that can be done without coming to a safepoint.
346 // It is likely that the basic allocation policy will not be very
347 // aggressive.
348 //
349 // The failed allocation policy is invoked from the VM thread after
350 // the basic allocation policy is unable to satisfy a mem_allocate
351 // request. This policy needs to cover the entire range of collection,
352 // heap expansion, and out-of-memory conditions. It should make every
353 // attempt to allocate the requested memory.
354
355 // Basic allocation policy. Should never be called at a safepoint, or
356 // from the VM thread.
357 //
358 // This method must handle cases where many mem_allocate requests fail
359 // simultaneously. When that happens, only one VM operation will succeed,
360 // and the rest will not be executed. For that reason, this method loops
361 // during failed allocation attempts. If the java heap becomes exhausted,
362 // we rely on the size_policy object to force a bail out.
363 HeapWord* ParallelScavengeHeap::mem_allocate(
364 size_t size,
365 bool is_noref,
366 bool is_tlab,
367 bool* gc_overhead_limit_was_exceeded) {
368 assert(!SafepointSynchronize::is_at_safepoint(), "should not be at safepoint");
369 assert(Thread::current() != (Thread*)VMThread::vm_thread(), "should not be in vm thread");
370 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
371
372 HeapWord* result = young_gen()->allocate(size, is_tlab);
373
374 uint loop_count = 0;
375 uint gc_count = 0;
376
377 while (result == NULL) {
378 // We don't want to have multiple collections for a single filled generation.
379 // To prevent this, each thread tracks the total_collections() value, and if
380 // the count has changed, does not do a new collection.
381 //
382 // The collection count must be read only while holding the heap lock. VM
383 // operations also hold the heap lock during collections. There is a lock
384 // contention case where thread A blocks waiting on the Heap_lock, while
385 // thread B is holding it doing a collection. When thread A gets the lock,
386 // the collection count has already changed. To prevent duplicate collections,
387 // The policy MUST attempt allocations during the same period it reads the
388 // total_collections() value!
389 {
390 MutexLocker ml(Heap_lock);
391 gc_count = Universe::heap()->total_collections();
392
393 result = young_gen()->allocate(size, is_tlab);
394
395 // (1) If the requested object is too large to easily fit in the
396 // young_gen, or
397 // (2) If GC is locked out via GCLocker, young gen is full and
398 // the need for a GC already signalled to GCLocker (done
399 // at a safepoint),
400 // ... then, rather than force a safepoint and (a potentially futile)
401 // collection (attempt) for each allocation, try allocation directly
402 // in old_gen. For case (2) above, we may in the future allow
403 // TLAB allocation directly in the old gen.
404 if (result != NULL) {
405 return result;
406 }
407 if (!is_tlab &&
408 size >= (young_gen()->eden_space()->capacity_in_words() / 2)) {
409 result = old_gen()->allocate(size, is_tlab);
410 if (result != NULL) {
411 return result;
412 }
413 }
414 if (GC_locker::is_active_and_needs_gc()) {
415 // GC is locked out. If this is a TLAB allocation,
416 // return NULL; the requestor will retry allocation
417 // of an idividual object at a time.
418 if (is_tlab) {
419 return NULL;
420 }
421
422 // If this thread is not in a jni critical section, we stall
423 // the requestor until the critical section has cleared and
424 // GC allowed. When the critical section clears, a GC is
425 // initiated by the last thread exiting the critical section; so
426 // we retry the allocation sequence from the beginning of the loop,
427 // rather than causing more, now probably unnecessary, GC attempts.
428 JavaThread* jthr = JavaThread::current();
429 if (!jthr->in_critical()) {
430 MutexUnlocker mul(Heap_lock);
431 GC_locker::stall_until_clear();
432 continue;
433 } else {
434 if (CheckJNICalls) {
435 fatal("Possible deadlock due to allocating while"
436 " in jni critical section");
437 }
438 return NULL;
439 }
440 }
441 }
442
443 if (result == NULL) {
444
445 // Exit the loop if if the gc time limit has been exceeded.
446 // The allocation must have failed above (result must be NULL),
447 // and the most recent collection must have exceeded the
448 // gc time limit. Exit the loop so that an out-of-memory
449 // will be thrown (returning a NULL will do that), but
450 // clear gc_time_limit_exceeded so that the next collection
451 // will succeeded if the applications decides to handle the
452 // out-of-memory and tries to go on.
453 *gc_overhead_limit_was_exceeded = size_policy()->gc_time_limit_exceeded();
454 if (size_policy()->gc_time_limit_exceeded()) {
455 size_policy()->set_gc_time_limit_exceeded(false);
456 if (PrintGCDetails && Verbose) {
457 gclog_or_tty->print_cr("ParallelScavengeHeap::mem_allocate: "
458 "return NULL because gc_time_limit_exceeded is set");
459 }
460 return NULL;
461 }
462
463 // Generate a VM operation
464 VM_ParallelGCFailedAllocation op(size, is_tlab, gc_count);
465 VMThread::execute(&op);
466
467 // Did the VM operation execute? If so, return the result directly.
468 // This prevents us from looping until time out on requests that can
469 // not be satisfied.
470 if (op.prologue_succeeded()) {
471 assert(Universe::heap()->is_in_or_null(op.result()),
472 "result not in heap");
473
474 // If GC was locked out during VM operation then retry allocation
475 // and/or stall as necessary.
476 if (op.gc_locked()) {
477 assert(op.result() == NULL, "must be NULL if gc_locked() is true");
478 continue; // retry and/or stall as necessary
479 }
480 // If a NULL result is being returned, an out-of-memory
481 // will be thrown now. Clear the gc_time_limit_exceeded
482 // flag to avoid the following situation.
483 // gc_time_limit_exceeded is set during a collection
484 // the collection fails to return enough space and an OOM is thrown
485 // the next GC is skipped because the gc_time_limit_exceeded
486 // flag is set and another OOM is thrown
487 if (op.result() == NULL) {
488 size_policy()->set_gc_time_limit_exceeded(false);
489 }
490 return op.result();
491 }
492 }
493
494 // The policy object will prevent us from looping forever. If the
495 // time spent in gc crosses a threshold, we will bail out.
496 loop_count++;
497 if ((result == NULL) && (QueuedAllocationWarningCount > 0) &&
498 (loop_count % QueuedAllocationWarningCount == 0)) {
499 warning("ParallelScavengeHeap::mem_allocate retries %d times \n\t"
500 " size=%d %s", loop_count, size, is_tlab ? "(TLAB)" : "");
501 }
502 }
503
504 return result;
505 }
506
507 // Failed allocation policy. Must be called from the VM thread, and
508 // only at a safepoint! Note that this method has policy for allocation
509 // flow, and NOT collection policy. So we do not check for gc collection
510 // time over limit here, that is the responsibility of the heap specific
511 // collection methods. This method decides where to attempt allocations,
512 // and when to attempt collections, but no collection specific policy.
513 HeapWord* ParallelScavengeHeap::failed_mem_allocate(size_t size, bool is_tlab) {
514 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
515 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
516 assert(!Universe::heap()->is_gc_active(), "not reentrant");
517 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
518
519 size_t mark_sweep_invocation_count = total_invocations();
520
521 // We assume (and assert!) that an allocation at this point will fail
522 // unless we collect.
523
524 // First level allocation failure, scavenge and allocate in young gen.
525 GCCauseSetter gccs(this, GCCause::_allocation_failure);
526 PSScavenge::invoke();
527 HeapWord* result = young_gen()->allocate(size, is_tlab);
528
529 // Second level allocation failure.
530 // Mark sweep and allocate in young generation.
531 if (result == NULL) {
532 // There is some chance the scavenge method decided to invoke mark_sweep.
533 // Don't mark sweep twice if so.
534 if (mark_sweep_invocation_count == total_invocations()) {
535 invoke_full_gc(false);
536 result = young_gen()->allocate(size, is_tlab);
537 }
538 }
539
540 // Third level allocation failure.
541 // After mark sweep and young generation allocation failure,
542 // allocate in old generation.
543 if (result == NULL && !is_tlab) {
544 result = old_gen()->allocate(size, is_tlab);
545 }
546
547 // Fourth level allocation failure. We're running out of memory.
548 // More complete mark sweep and allocate in young generation.
549 if (result == NULL) {
550 invoke_full_gc(true);
551 result = young_gen()->allocate(size, is_tlab);
552 }
553
554 // Fifth level allocation failure.
555 // After more complete mark sweep, allocate in old generation.
556 if (result == NULL && !is_tlab) {
557 result = old_gen()->allocate(size, is_tlab);
558 }
559
560 return result;
561 }
562
563 //
564 // This is the policy loop for allocating in the permanent generation.
565 // If the initial allocation fails, we create a vm operation which will
566 // cause a collection.
567 HeapWord* ParallelScavengeHeap::permanent_mem_allocate(size_t size) {
568 assert(!SafepointSynchronize::is_at_safepoint(), "should not be at safepoint");
569 assert(Thread::current() != (Thread*)VMThread::vm_thread(), "should not be in vm thread");
570 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
571
572 HeapWord* result;
573
574 uint loop_count = 0;
575 uint gc_count = 0;
576 uint full_gc_count = 0;
577
578 do {
579 // We don't want to have multiple collections for a single filled generation.
580 // To prevent this, each thread tracks the total_collections() value, and if
581 // the count has changed, does not do a new collection.
582 //
583 // The collection count must be read only while holding the heap lock. VM
584 // operations also hold the heap lock during collections. There is a lock
585 // contention case where thread A blocks waiting on the Heap_lock, while
586 // thread B is holding it doing a collection. When thread A gets the lock,
587 // the collection count has already changed. To prevent duplicate collections,
588 // The policy MUST attempt allocations during the same period it reads the
589 // total_collections() value!
590 {
591 MutexLocker ml(Heap_lock);
592 gc_count = Universe::heap()->total_collections();
593 full_gc_count = Universe::heap()->total_full_collections();
594
595 result = perm_gen()->allocate_permanent(size);
596 }
597
598 if (result == NULL) {
599
600 // Exit the loop if the gc time limit has been exceeded.
601 // The allocation must have failed above (result must be NULL),
602 // and the most recent collection must have exceeded the
603 // gc time limit. Exit the loop so that an out-of-memory
604 // will be thrown (returning a NULL will do that), but
605 // clear gc_time_limit_exceeded so that the next collection
606 // will succeeded if the applications decides to handle the
607 // out-of-memory and tries to go on.
608 if (size_policy()->gc_time_limit_exceeded()) {
609 size_policy()->set_gc_time_limit_exceeded(false);
610 if (PrintGCDetails && Verbose) {
611 gclog_or_tty->print_cr("ParallelScavengeHeap::permanent_mem_allocate: "
612 "return NULL because gc_time_limit_exceeded is set");
613 }
614 assert(result == NULL, "Allocation did not fail");
615 return NULL;
616 }
617
618 // Generate a VM operation
619 VM_ParallelGCFailedPermanentAllocation op(size, gc_count, full_gc_count);
620 VMThread::execute(&op);
621
622 // Did the VM operation execute? If so, return the result directly.
623 // This prevents us from looping until time out on requests that can
624 // not be satisfied.
625 if (op.prologue_succeeded()) {
626 assert(Universe::heap()->is_in_permanent_or_null(op.result()),
627 "result not in heap");
628 // If a NULL results is being returned, an out-of-memory
629 // will be thrown now. Clear the gc_time_limit_exceeded
630 // flag to avoid the following situation.
631 // gc_time_limit_exceeded is set during a collection
632 // the collection fails to return enough space and an OOM is thrown
633 // the next GC is skipped because the gc_time_limit_exceeded
634 // flag is set and another OOM is thrown
635 if (op.result() == NULL) {
636 size_policy()->set_gc_time_limit_exceeded(false);
637 }
638 return op.result();
639 }
640 }
641
642 // The policy object will prevent us from looping forever. If the
643 // time spent in gc crosses a threshold, we will bail out.
644 loop_count++;
645 if ((QueuedAllocationWarningCount > 0) &&
646 (loop_count % QueuedAllocationWarningCount == 0)) {
647 warning("ParallelScavengeHeap::permanent_mem_allocate retries %d times \n\t"
648 " size=%d", loop_count, size);
649 }
650 } while (result == NULL);
651
652 return result;
653 }
654
655 //
656 // This is the policy code for permanent allocations which have failed
657 // and require a collection. Note that just as in failed_mem_allocate,
658 // we do not set collection policy, only where & when to allocate and
659 // collect.
660 HeapWord* ParallelScavengeHeap::failed_permanent_mem_allocate(size_t size) {
661 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
662 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
663 assert(!Universe::heap()->is_gc_active(), "not reentrant");
664 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
665 assert(size > perm_gen()->free_in_words(), "Allocation should fail");
666
667 // We assume (and assert!) that an allocation at this point will fail
668 // unless we collect.
669
670 // First level allocation failure. Mark-sweep and allocate in perm gen.
671 GCCauseSetter gccs(this, GCCause::_allocation_failure);
672 invoke_full_gc(false);
673 HeapWord* result = perm_gen()->allocate_permanent(size);
674
675 // Second level allocation failure. We're running out of memory.
676 if (result == NULL) {
677 invoke_full_gc(true);
678 result = perm_gen()->allocate_permanent(size);
679 }
680
681 return result;
682 }
683
684 void ParallelScavengeHeap::ensure_parsability(bool retire_tlabs) {
685 CollectedHeap::ensure_parsability(retire_tlabs);
686 young_gen()->eden_space()->ensure_parsability();
687 }
688
689 size_t ParallelScavengeHeap::unsafe_max_alloc() {
690 return young_gen()->eden_space()->free_in_bytes();
691 }
692
693 size_t ParallelScavengeHeap::tlab_capacity(Thread* thr) const {
694 return young_gen()->eden_space()->tlab_capacity(thr);
695 }
696
697 size_t ParallelScavengeHeap::unsafe_max_tlab_alloc(Thread* thr) const {
698 return young_gen()->eden_space()->unsafe_max_tlab_alloc(thr);
699 }
700
701 HeapWord* ParallelScavengeHeap::allocate_new_tlab(size_t size) {
702 return young_gen()->allocate(size, true);
703 }
704
705 void ParallelScavengeHeap::fill_all_tlabs(bool retire) {
706 CollectedHeap::fill_all_tlabs(retire);
707 }
708
709 void ParallelScavengeHeap::accumulate_statistics_all_tlabs() {
710 CollectedHeap::accumulate_statistics_all_tlabs();
711 }
712
713 void ParallelScavengeHeap::resize_all_tlabs() {
714 CollectedHeap::resize_all_tlabs();
715 }
716
717 // This method is used by System.gc() and JVMTI.
718 void ParallelScavengeHeap::collect(GCCause::Cause cause) {
719 assert(!Heap_lock->owned_by_self(),
720 "this thread should not own the Heap_lock");
721
722 unsigned int gc_count = 0;
723 unsigned int full_gc_count = 0;
724 {
725 MutexLocker ml(Heap_lock);
726 // This value is guarded by the Heap_lock
727 gc_count = Universe::heap()->total_collections();
728 full_gc_count = Universe::heap()->total_full_collections();
729 }
730
731 VM_ParallelGCSystemGC op(gc_count, full_gc_count, cause);
732 VMThread::execute(&op);
733 }
734
735 // This interface assumes that it's being called by the
736 // vm thread. It collects the heap assuming that the
737 // heap lock is already held and that we are executing in
738 // the context of the vm thread.
739 void ParallelScavengeHeap::collect_as_vm_thread(GCCause::Cause cause) {
740 assert(Thread::current()->is_VM_thread(), "Precondition#1");
741 assert(Heap_lock->is_locked(), "Precondition#2");
742 GCCauseSetter gcs(this, cause);
743 switch (cause) {
744 case GCCause::_heap_inspection:
745 case GCCause::_heap_dump: {
746 HandleMark hm;
747 invoke_full_gc(false);
748 break;
749 }
750 default: // XXX FIX ME
751 ShouldNotReachHere();
752 }
753 }
754
755
756 void ParallelScavengeHeap::oop_iterate(OopClosure* cl) {
757 Unimplemented();
758 }
759
760 void ParallelScavengeHeap::object_iterate(ObjectClosure* cl) {
761 young_gen()->object_iterate(cl);
762 old_gen()->object_iterate(cl);
763 perm_gen()->object_iterate(cl);
764 }
765
766 void ParallelScavengeHeap::permanent_oop_iterate(OopClosure* cl) {
767 Unimplemented();
768 }
769
770 void ParallelScavengeHeap::permanent_object_iterate(ObjectClosure* cl) {
771 perm_gen()->object_iterate(cl);
772 }
773
774 HeapWord* ParallelScavengeHeap::block_start(const void* addr) const {
775 if (young_gen()->is_in_reserved(addr)) {
776 assert(young_gen()->is_in(addr),
777 "addr should be in allocated part of young gen");
778 Unimplemented();
779 } else if (old_gen()->is_in_reserved(addr)) {
780 assert(old_gen()->is_in(addr),
781 "addr should be in allocated part of old gen");
782 return old_gen()->start_array()->object_start((HeapWord*)addr);
783 } else if (perm_gen()->is_in_reserved(addr)) {
784 assert(perm_gen()->is_in(addr),
785 "addr should be in allocated part of perm gen");
786 return perm_gen()->start_array()->object_start((HeapWord*)addr);
787 }
788 return 0;
789 }
790
791 size_t ParallelScavengeHeap::block_size(const HeapWord* addr) const {
792 return oop(addr)->size();
793 }
794
795 bool ParallelScavengeHeap::block_is_obj(const HeapWord* addr) const {
796 return block_start(addr) == addr;
797 }
798
799 jlong ParallelScavengeHeap::millis_since_last_gc() {
800 return UseParallelOldGC ?
801 PSParallelCompact::millis_since_last_gc() :
802 PSMarkSweep::millis_since_last_gc();
803 }
804
805 void ParallelScavengeHeap::prepare_for_verify() {
806 ensure_parsability(false); // no need to retire TLABs for verification
807 }
808
809 void ParallelScavengeHeap::print() const { print_on(tty); }
810
811 void ParallelScavengeHeap::print_on(outputStream* st) const {
812 young_gen()->print_on(st);
813 old_gen()->print_on(st);
814 perm_gen()->print_on(st);
815 }
816
817 void ParallelScavengeHeap::gc_threads_do(ThreadClosure* tc) const {
818 PSScavenge::gc_task_manager()->threads_do(tc);
819 }
820
821 void ParallelScavengeHeap::print_gc_threads_on(outputStream* st) const {
822 PSScavenge::gc_task_manager()->print_threads_on(st);
823 }
824
825 void ParallelScavengeHeap::print_tracing_info() const {
826 if (TraceGen0Time) {
827 double time = PSScavenge::accumulated_time()->seconds();
828 tty->print_cr("[Accumulated GC generation 0 time %3.7f secs]", time);
829 }
830 if (TraceGen1Time) {
831 double time = PSMarkSweep::accumulated_time()->seconds();
832 tty->print_cr("[Accumulated GC generation 1 time %3.7f secs]", time);
833 }
834 }
835
836
837 void ParallelScavengeHeap::verify(bool allow_dirty, bool silent) {
838 // Why do we need the total_collections()-filter below?
839 if (total_collections() > 0) {
840 if (!silent) {
841 gclog_or_tty->print("permanent ");
842 }
843 perm_gen()->verify(allow_dirty);
844
845 if (!silent) {
846 gclog_or_tty->print("tenured ");
847 }
848 old_gen()->verify(allow_dirty);
849
850 if (!silent) {
851 gclog_or_tty->print("eden ");
852 }
853 young_gen()->verify(allow_dirty);
854 }
855 if (!silent) {
856 gclog_or_tty->print("ref_proc ");
857 }
858 ReferenceProcessor::verify();
859 }
860
861 void ParallelScavengeHeap::print_heap_change(size_t prev_used) {
862 if (PrintGCDetails && Verbose) {
863 gclog_or_tty->print(" " SIZE_FORMAT
864 "->" SIZE_FORMAT
865 "(" SIZE_FORMAT ")",
866 prev_used, used(), capacity());
867 } else {
868 gclog_or_tty->print(" " SIZE_FORMAT "K"
869 "->" SIZE_FORMAT "K"
870 "(" SIZE_FORMAT "K)",
871 prev_used / K, used() / K, capacity() / K);
872 }
873 }
874
875 ParallelScavengeHeap* ParallelScavengeHeap::heap() {
876 assert(_psh != NULL, "Uninitialized access to ParallelScavengeHeap::heap()");
877 assert(_psh->kind() == CollectedHeap::ParallelScavengeHeap, "not a parallel scavenge heap");
878 return _psh;
879 }
880
881 // Before delegating the resize to the young generation,
882 // the reserved space for the young and old generations
883 // may be changed to accomodate the desired resize.
884 void ParallelScavengeHeap::resize_young_gen(size_t eden_size,
885 size_t survivor_size) {
886 if (UseAdaptiveGCBoundary) {
887 if (size_policy()->bytes_absorbed_from_eden() != 0) {
888 size_policy()->reset_bytes_absorbed_from_eden();
889 return; // The generation changed size already.
890 }
891 gens()->adjust_boundary_for_young_gen_needs(eden_size, survivor_size);
892 }
893
894 // Delegate the resize to the generation.
895 _young_gen->resize(eden_size, survivor_size);
896 }
897
898 // Before delegating the resize to the old generation,
899 // the reserved space for the young and old generations
900 // may be changed to accomodate the desired resize.
901 void ParallelScavengeHeap::resize_old_gen(size_t desired_free_space) {
902 if (UseAdaptiveGCBoundary) {
903 if (size_policy()->bytes_absorbed_from_eden() != 0) {
904 size_policy()->reset_bytes_absorbed_from_eden();
905 return; // The generation changed size already.
906 }
907 gens()->adjust_boundary_for_old_gen_needs(desired_free_space);
908 }
909
910 // Delegate the resize to the generation.
911 _old_gen->resize(desired_free_space);
912 }