1 /*
2 * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
27 #include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp"
28 #include "gc_implementation/parallelScavenge/psMarkSweepDecorator.hpp"
29 #include "gc_implementation/parallelScavenge/psOldGen.hpp"
30 #include "gc_implementation/shared/spaceDecorator.hpp"
31 #include "memory/cardTableModRefBS.hpp"
32 #include "memory/gcLocker.inline.hpp"
33 #include "oops/oop.inline.hpp"
34 #include "runtime/java.hpp"
35
36 inline const char* PSOldGen::select_name() {
37 return UseParallelOldGC ? "ParOldGen" : "PSOldGen";
38 }
39
40 PSOldGen::PSOldGen(ReservedSpace rs, size_t alignment,
41 size_t initial_size, size_t min_size, size_t max_size,
42 const char* perf_data_name, int level):
43 _name(select_name()), _init_gen_size(initial_size), _min_gen_size(min_size),
44 _max_gen_size(max_size)
45 {
46 initialize(rs, alignment, perf_data_name, level);
47 }
48
49 PSOldGen::PSOldGen(size_t initial_size,
50 size_t min_size, size_t max_size,
51 const char* perf_data_name, int level):
52 _name(select_name()), _init_gen_size(initial_size), _min_gen_size(min_size),
53 _max_gen_size(max_size)
54 {}
55
56 void PSOldGen::initialize(ReservedSpace rs, size_t alignment,
57 const char* perf_data_name, int level) {
58 initialize_virtual_space(rs, alignment);
59 initialize_work(perf_data_name, level);
60 // The old gen can grow to gen_size_limit(). _reserve reflects only
61 // the current maximum that can be committed.
62 assert(_reserved.byte_size() <= gen_size_limit(), "Consistency check");
63 }
64
65 void PSOldGen::initialize_virtual_space(ReservedSpace rs, size_t alignment) {
66
67 _virtual_space = new PSVirtualSpace(rs, alignment);
68 if (!_virtual_space->expand_by(_init_gen_size)) {
69 vm_exit_during_initialization("Could not reserve enough space for "
70 "object heap");
71 }
72 }
73
74 void PSOldGen::initialize_work(const char* perf_data_name, int level) {
75 //
76 // Basic memory initialization
77 //
78
79 MemRegion limit_reserved((HeapWord*)virtual_space()->low_boundary(),
80 heap_word_size(_max_gen_size));
81 assert(limit_reserved.byte_size() == _max_gen_size,
82 "word vs bytes confusion");
83 //
84 // Object start stuff
85 //
86
87 start_array()->initialize(limit_reserved);
88
89 _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
90 (HeapWord*)virtual_space()->high_boundary());
91
92 //
93 // Card table stuff
94 //
95
96 MemRegion cmr((HeapWord*)virtual_space()->low(),
97 (HeapWord*)virtual_space()->high());
98 if (ZapUnusedHeapArea) {
99 // Mangle newly committed space immediately rather than
100 // waiting for the initialization of the space even though
101 // mangling is related to spaces. Doing it here eliminates
102 // the need to carry along information that a complete mangling
103 // (bottom to end) needs to be done.
104 SpaceMangler::mangle_region(cmr);
105 }
106
107 Universe::heap()->barrier_set()->resize_covered_region(cmr);
108
109 CardTableModRefBS* _ct = (CardTableModRefBS*)Universe::heap()->barrier_set();
110 assert (_ct->kind() == BarrierSet::CardTableModRef, "Sanity");
111
112 // Verify that the start and end of this generation is the start of a card.
113 // If this wasn't true, a single card could span more than one generation,
114 // which would cause problems when we commit/uncommit memory, and when we
115 // clear and dirty cards.
116 guarantee(_ct->is_card_aligned(_reserved.start()), "generation must be card aligned");
117 if (_reserved.end() != Universe::heap()->reserved_region().end()) {
118 // Don't check at the very end of the heap as we'll assert that we're probing off
119 // the end if we try.
120 guarantee(_ct->is_card_aligned(_reserved.end()), "generation must be card aligned");
121 }
122
123 //
124 // ObjectSpace stuff
125 //
126
127 _object_space = new MutableSpace(virtual_space()->alignment());
128
129 if (_object_space == NULL)
130 vm_exit_during_initialization("Could not allocate an old gen space");
131
132 object_space()->initialize(cmr,
133 SpaceDecorator::Clear,
134 SpaceDecorator::Mangle);
135
136 _object_mark_sweep = new PSMarkSweepDecorator(_object_space, start_array(), MarkSweepDeadRatio);
137
138 if (_object_mark_sweep == NULL)
139 vm_exit_during_initialization("Could not complete allocation of old generation");
140
141 // Update the start_array
142 start_array()->set_covered_region(cmr);
143
144 // Generation Counters, generation 'level', 1 subspace
145 _gen_counters = new PSGenerationCounters(perf_data_name, level, 1,
146 virtual_space());
147 _space_counters = new SpaceCounters(perf_data_name, 0,
148 virtual_space()->reserved_size(),
149 _object_space, _gen_counters);
150 }
151
152 // Assume that the generation has been allocated if its
153 // reserved size is not 0.
154 bool PSOldGen::is_allocated() {
155 return virtual_space()->reserved_size() != 0;
156 }
157
158 void PSOldGen::precompact() {
159 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
160 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
161
162 // Reset start array first.
163 start_array()->reset();
164
165 object_mark_sweep()->precompact();
166
167 // Now compact the young gen
168 heap->young_gen()->precompact();
169 }
170
171 void PSOldGen::adjust_pointers() {
172 object_mark_sweep()->adjust_pointers();
173 }
174
175 void PSOldGen::compact() {
176 object_mark_sweep()->compact(ZapUnusedHeapArea);
177 }
178
179 void PSOldGen::move_and_update(ParCompactionManager* cm) {
180 PSParallelCompact::move_and_update(cm, PSParallelCompact::old_space_id);
181 }
182
183 size_t PSOldGen::contiguous_available() const {
184 return object_space()->free_in_bytes() + virtual_space()->uncommitted_size();
185 }
186
187 // Allocation. We report all successful allocations to the size policy
188 // Note that the perm gen does not use this method, and should not!
189 HeapWord* PSOldGen::allocate(size_t word_size, bool is_tlab) {
190 assert_locked_or_safepoint(Heap_lock);
191 HeapWord* res = allocate_noexpand(word_size, is_tlab);
192
193 if (res == NULL) {
194 res = expand_and_allocate(word_size, is_tlab);
195 }
196
197 // Allocations in the old generation need to be reported
198 if (res != NULL) {
199 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
200 heap->size_policy()->tenured_allocation(word_size);
201 }
202
203 return res;
204 }
205
206 HeapWord* PSOldGen::expand_and_allocate(size_t word_size, bool is_tlab) {
207 assert(!is_tlab, "TLAB's are not supported in PSOldGen");
208 expand(word_size*HeapWordSize);
209 if (GCExpandToAllocateDelayMillis > 0) {
210 os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false);
211 }
212 return allocate_noexpand(word_size, is_tlab);
213 }
214
215 HeapWord* PSOldGen::expand_and_cas_allocate(size_t word_size) {
216 expand(word_size*HeapWordSize);
217 if (GCExpandToAllocateDelayMillis > 0) {
218 os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false);
219 }
220 return cas_allocate_noexpand(word_size);
221 }
222
223 void PSOldGen::expand(size_t bytes) {
224 if (bytes == 0) {
225 return;
226 }
227 MutexLocker x(ExpandHeap_lock);
228 const size_t alignment = virtual_space()->alignment();
229 size_t aligned_bytes = align_size_up(bytes, alignment);
230 size_t aligned_expand_bytes = align_size_up(MinHeapDeltaBytes, alignment);
231 if (aligned_bytes == 0){
232 // The alignment caused the number of bytes to wrap. An expand_by(0) will
233 // return true with the implication that and expansion was done when it
234 // was not. A call to expand implies a best effort to expand by "bytes"
235 // but not a guarantee. Align down to give a best effort. This is likely
236 // the most that the generation can expand since it has some capacity to
237 // start with.
238 aligned_bytes = align_size_down(bytes, alignment);
239 }
240
241 bool success = false;
242 if (aligned_expand_bytes > aligned_bytes) {
243 success = expand_by(aligned_expand_bytes);
244 }
245 if (!success) {
246 success = expand_by(aligned_bytes);
247 }
248 if (!success) {
249 success = expand_to_reserved();
250 }
251
252 if (PrintGC && Verbose) {
253 if (success && GC_locker::is_active()) {
254 gclog_or_tty->print_cr("Garbage collection disabled, expanded heap instead");
255 }
256 }
257 }
258
259 bool PSOldGen::expand_by(size_t bytes) {
260 assert_lock_strong(ExpandHeap_lock);
261 assert_locked_or_safepoint(Heap_lock);
262 if (bytes == 0) {
263 return true; // That's what virtual_space()->expand_by(0) would return
264 }
265 bool result = virtual_space()->expand_by(bytes);
266 if (result) {
267 if (ZapUnusedHeapArea) {
268 // We need to mangle the newly expanded area. The memregion spans
269 // end -> new_end, we assume that top -> end is already mangled.
270 // Do the mangling before post_resize() is called because
271 // the space is available for allocation after post_resize();
272 HeapWord* const virtual_space_high = (HeapWord*) virtual_space()->high();
273 assert(object_space()->end() < virtual_space_high,
274 "Should be true before post_resize()");
275 MemRegion mangle_region(object_space()->end(), virtual_space_high);
276 // Note that the object space has not yet been updated to
277 // coincede with the new underlying virtual space.
278 SpaceMangler::mangle_region(mangle_region);
279 }
280 post_resize();
281 if (UsePerfData) {
282 _space_counters->update_capacity();
283 _gen_counters->update_all();
284 }
285 }
286
287 if (result && Verbose && PrintGC) {
288 size_t new_mem_size = virtual_space()->committed_size();
289 size_t old_mem_size = new_mem_size - bytes;
290 gclog_or_tty->print_cr("Expanding %s from " SIZE_FORMAT "K by "
291 SIZE_FORMAT "K to "
292 SIZE_FORMAT "K",
293 name(), old_mem_size/K, bytes/K, new_mem_size/K);
294 }
295
296 return result;
297 }
298
299 bool PSOldGen::expand_to_reserved() {
300 assert_lock_strong(ExpandHeap_lock);
301 assert_locked_or_safepoint(Heap_lock);
302
303 bool result = true;
304 const size_t remaining_bytes = virtual_space()->uncommitted_size();
305 if (remaining_bytes > 0) {
306 result = expand_by(remaining_bytes);
307 DEBUG_ONLY(if (!result) warning("grow to reserve failed"));
308 }
309 return result;
310 }
311
312 void PSOldGen::shrink(size_t bytes) {
313 assert_lock_strong(ExpandHeap_lock);
314 assert_locked_or_safepoint(Heap_lock);
315
316 size_t size = align_size_down(bytes, virtual_space()->alignment());
317 if (size > 0) {
318 assert_lock_strong(ExpandHeap_lock);
319 virtual_space()->shrink_by(bytes);
320 post_resize();
321
322 if (Verbose && PrintGC) {
323 size_t new_mem_size = virtual_space()->committed_size();
324 size_t old_mem_size = new_mem_size + bytes;
325 gclog_or_tty->print_cr("Shrinking %s from " SIZE_FORMAT "K by "
326 SIZE_FORMAT "K to "
327 SIZE_FORMAT "K",
328 name(), old_mem_size/K, bytes/K, new_mem_size/K);
329 }
330 }
331 }
332
333 void PSOldGen::resize(size_t desired_free_space) {
334 const size_t alignment = virtual_space()->alignment();
335 const size_t size_before = virtual_space()->committed_size();
336 size_t new_size = used_in_bytes() + desired_free_space;
337 if (new_size < used_in_bytes()) {
338 // Overflowed the addition.
339 new_size = gen_size_limit();
340 }
341 // Adjust according to our min and max
342 new_size = MAX2(MIN2(new_size, gen_size_limit()), min_gen_size());
343
344 assert(gen_size_limit() >= reserved().byte_size(), "max new size problem?");
345 new_size = align_size_up(new_size, alignment);
346
347 const size_t current_size = capacity_in_bytes();
348
349 if (PrintAdaptiveSizePolicy && Verbose) {
350 gclog_or_tty->print_cr("AdaptiveSizePolicy::old generation size: "
351 "desired free: " SIZE_FORMAT " used: " SIZE_FORMAT
352 " new size: " SIZE_FORMAT " current size " SIZE_FORMAT
353 " gen limits: " SIZE_FORMAT " / " SIZE_FORMAT,
354 desired_free_space, used_in_bytes(), new_size, current_size,
355 gen_size_limit(), min_gen_size());
356 }
357
358 if (new_size == current_size) {
359 // No change requested
360 return;
361 }
362 if (new_size > current_size) {
363 size_t change_bytes = new_size - current_size;
364 expand(change_bytes);
365 } else {
366 size_t change_bytes = current_size - new_size;
367 // shrink doesn't grab this lock, expand does. Is that right?
368 MutexLocker x(ExpandHeap_lock);
369 shrink(change_bytes);
370 }
371
372 if (PrintAdaptiveSizePolicy) {
373 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
374 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
375 gclog_or_tty->print_cr("AdaptiveSizePolicy::old generation size: "
376 "collection: %d "
377 "(" SIZE_FORMAT ") -> (" SIZE_FORMAT ") ",
378 heap->total_collections(),
379 size_before, virtual_space()->committed_size());
380 }
381 }
382
383 // NOTE! We need to be careful about resizing. During a GC, multiple
384 // allocators may be active during heap expansion. If we allow the
385 // heap resizing to become visible before we have correctly resized
386 // all heap related data structures, we may cause program failures.
387 void PSOldGen::post_resize() {
388 // First construct a memregion representing the new size
389 MemRegion new_memregion((HeapWord*)virtual_space()->low(),
390 (HeapWord*)virtual_space()->high());
391 size_t new_word_size = new_memregion.word_size();
392
393 start_array()->set_covered_region(new_memregion);
394 Universe::heap()->barrier_set()->resize_covered_region(new_memregion);
395
396 // ALWAYS do this last!!
397 object_space()->initialize(new_memregion,
398 SpaceDecorator::DontClear,
399 SpaceDecorator::DontMangle);
400
401 assert(new_word_size == heap_word_size(object_space()->capacity_in_bytes()),
402 "Sanity");
403 }
404
405 size_t PSOldGen::gen_size_limit() {
406 return _max_gen_size;
407 }
408
409 void PSOldGen::reset_after_change() {
410 ShouldNotReachHere();
411 return;
412 }
413
414 size_t PSOldGen::available_for_expansion() {
415 ShouldNotReachHere();
416 return 0;
417 }
418
419 size_t PSOldGen::available_for_contraction() {
420 ShouldNotReachHere();
421 return 0;
422 }
423
424 void PSOldGen::print() const { print_on(tty);}
425 void PSOldGen::print_on(outputStream* st) const {
426 st->print(" %-15s", name());
427 if (PrintGCDetails && Verbose) {
428 st->print(" total " SIZE_FORMAT ", used " SIZE_FORMAT,
429 capacity_in_bytes(), used_in_bytes());
430 } else {
431 st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K",
432 capacity_in_bytes()/K, used_in_bytes()/K);
433 }
434 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")",
435 virtual_space()->low_boundary(),
436 virtual_space()->high(),
437 virtual_space()->high_boundary());
438
439 st->print(" object"); object_space()->print_on(st);
440 }
441
442 void PSOldGen::print_used_change(size_t prev_used) const {
443 gclog_or_tty->print(" [%s:", name());
444 gclog_or_tty->print(" " SIZE_FORMAT "K"
445 "->" SIZE_FORMAT "K"
446 "(" SIZE_FORMAT "K)",
447 prev_used / K, used_in_bytes() / K,
448 capacity_in_bytes() / K);
449 gclog_or_tty->print("]");
450 }
451
452 void PSOldGen::update_counters() {
453 if (UsePerfData) {
454 _space_counters->update_all();
455 _gen_counters->update_all();
456 }
457 }
458
459 #ifndef PRODUCT
460
461 void PSOldGen::space_invariants() {
462 assert(object_space()->end() == (HeapWord*) virtual_space()->high(),
463 "Space invariant");
464 assert(object_space()->bottom() == (HeapWord*) virtual_space()->low(),
465 "Space invariant");
466 assert(virtual_space()->low_boundary() <= virtual_space()->low(),
467 "Space invariant");
468 assert(virtual_space()->high_boundary() >= virtual_space()->high(),
469 "Space invariant");
470 assert(virtual_space()->low_boundary() == (char*) _reserved.start(),
471 "Space invariant");
472 assert(virtual_space()->high_boundary() == (char*) _reserved.end(),
473 "Space invariant");
474 assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(),
475 "Space invariant");
476 }
477 #endif
478
479 void PSOldGen::verify(bool allow_dirty) {
480 object_space()->verify(allow_dirty);
481 }
482 class VerifyObjectStartArrayClosure : public ObjectClosure {
483 PSOldGen* _gen;
484 ObjectStartArray* _start_array;
485
486 public:
487 VerifyObjectStartArrayClosure(PSOldGen* gen, ObjectStartArray* start_array) :
488 _gen(gen), _start_array(start_array) { }
489
490 virtual void do_object(oop obj) {
491 HeapWord* test_addr = (HeapWord*)obj + 1;
492 guarantee(_start_array->object_start(test_addr) == (HeapWord*)obj, "ObjectStartArray cannot find start of object");
493 guarantee(_start_array->is_block_allocated((HeapWord*)obj), "ObjectStartArray missing block allocation");
494 }
495 };
496
497 void PSOldGen::verify_object_start_array() {
498 VerifyObjectStartArrayClosure check( this, &_start_array );
499 object_iterate(&check);
500 }
501
502 #ifndef PRODUCT
503 void PSOldGen::record_spaces_top() {
504 assert(ZapUnusedHeapArea, "Not mangling unused space");
505 object_space()->set_top_for_allocations();
506 }
507 #endif