1/*
2 * Copyright (c) 2001, 2018, 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.
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23 */
24
25#include "precompiled.hpp"
26#include "gc/parallel/objectStartArray.inline.hpp"
27#include "gc/parallel/parallelArguments.hpp"
28#include "gc/parallel/parallelScavengeHeap.hpp"
29#include "gc/parallel/psAdaptiveSizePolicy.hpp"
30#include "gc/parallel/psCardTable.hpp"
31#include "gc/parallel/psFileBackedVirtualspace.hpp"
32#include "gc/parallel/psMarkSweepDecorator.hpp"
33#include "gc/parallel/psOldGen.hpp"
34#include "gc/shared/cardTableBarrierSet.hpp"
35#include "gc/shared/gcLocker.hpp"
36#include "gc/shared/spaceDecorator.hpp"
37#include "logging/log.hpp"
38#include "oops/oop.inline.hpp"
39#include "runtime/java.hpp"
40#include "utilities/align.hpp"
41
42inline const char* PSOldGen::select_name() {
43 return UseParallelOldGC ? "ParOldGen" : "PSOldGen";
44}
45
46PSOldGen::PSOldGen(ReservedSpace rs, size_t alignment,
47 size_t initial_size, size_t min_size, size_t max_size,
48 const char* perf_data_name, int level):
49 _name(select_name()), _init_gen_size(initial_size), _min_gen_size(min_size),
50 _max_gen_size(max_size)
51{
52 initialize(rs, alignment, perf_data_name, level);
53}
54
55PSOldGen::PSOldGen(size_t initial_size,
56 size_t min_size, size_t max_size,
57 const char* perf_data_name, int level):
58 _name(select_name()), _init_gen_size(initial_size), _min_gen_size(min_size),
59 _max_gen_size(max_size)
60{}
61
62void PSOldGen::initialize(ReservedSpace rs, size_t alignment,
63 const char* perf_data_name, int level) {
64 initialize_virtual_space(rs, alignment);
65 initialize_work(perf_data_name, level);
66
67 // The old gen can grow to gen_size_limit(). _reserve reflects only
68 // the current maximum that can be committed.
69 assert(_reserved.byte_size() <= gen_size_limit(), "Consistency check");
70
71 initialize_performance_counters(perf_data_name, level);
72}
73
74void PSOldGen::initialize_virtual_space(ReservedSpace rs, size_t alignment) {
75
76 if(ParallelArguments::is_heterogeneous_heap()) {
77 _virtual_space = new PSFileBackedVirtualSpace(rs, alignment, AllocateOldGenAt);
78 if (!(static_cast <PSFileBackedVirtualSpace*>(_virtual_space))->initialize()) {
79 vm_exit_during_initialization("Could not map space for PSOldGen at given AllocateOldGenAt path");
80 }
81 } else {
82 _virtual_space = new PSVirtualSpace(rs, alignment);
83 }
84 if (!_virtual_space->expand_by(_init_gen_size)) {
85 vm_exit_during_initialization("Could not reserve enough space for "
86 "object heap");
87 }
88}
89
90void PSOldGen::initialize_work(const char* perf_data_name, int level) {
91 //
92 // Basic memory initialization
93 //
94
95 MemRegion limit_reserved((HeapWord*)virtual_space()->low_boundary(),
96 heap_word_size(_max_gen_size));
97 assert(limit_reserved.byte_size() == _max_gen_size,
98 "word vs bytes confusion");
99 //
100 // Object start stuff
101 //
102
103 start_array()->initialize(limit_reserved);
104
105 _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
106 (HeapWord*)virtual_space()->high_boundary());
107
108 //
109 // Card table stuff
110 //
111
112 MemRegion cmr((HeapWord*)virtual_space()->low(),
113 (HeapWord*)virtual_space()->high());
114 if (ZapUnusedHeapArea) {
115 // Mangle newly committed space immediately rather than
116 // waiting for the initialization of the space even though
117 // mangling is related to spaces. Doing it here eliminates
118 // the need to carry along information that a complete mangling
119 // (bottom to end) needs to be done.
120 SpaceMangler::mangle_region(cmr);
121 }
122
123 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
124 PSCardTable* ct = heap->card_table();
125 ct->resize_covered_region(cmr);
126
127 // Verify that the start and end of this generation is the start of a card.
128 // If this wasn't true, a single card could span more than one generation,
129 // which would cause problems when we commit/uncommit memory, and when we
130 // clear and dirty cards.
131 guarantee(ct->is_card_aligned(_reserved.start()), "generation must be card aligned");
132 if (_reserved.end() != heap->reserved_region().end()) {
133 // Don't check at the very end of the heap as we'll assert that we're probing off
134 // the end if we try.
135 guarantee(ct->is_card_aligned(_reserved.end()), "generation must be card aligned");
136 }
137
138 //
139 // ObjectSpace stuff
140 //
141
142 _object_space = new MutableSpace(virtual_space()->alignment());
143
144 if (_object_space == NULL)
145 vm_exit_during_initialization("Could not allocate an old gen space");
146
147 object_space()->initialize(cmr,
148 SpaceDecorator::Clear,
149 SpaceDecorator::Mangle);
150
151#if INCLUDE_SERIALGC
152 _object_mark_sweep = new PSMarkSweepDecorator(_object_space, start_array(), MarkSweepDeadRatio);
153
154 if (_object_mark_sweep == NULL) {
155 vm_exit_during_initialization("Could not complete allocation of old generation");
156 }
157#endif // INCLUDE_SERIALGC
158
159 // Update the start_array
160 start_array()->set_covered_region(cmr);
161}
162
163void PSOldGen::initialize_performance_counters(const char* perf_data_name, int level) {
164 // Generation Counters, generation 'level', 1 subspace
165 _gen_counters = new PSGenerationCounters(perf_data_name, level, 1, _min_gen_size,
166 _max_gen_size, virtual_space());
167 _space_counters = new SpaceCounters(perf_data_name, 0,
168 virtual_space()->reserved_size(),
169 _object_space, _gen_counters);
170}
171
172// Assume that the generation has been allocated if its
173// reserved size is not 0.
174bool PSOldGen::is_allocated() {
175 return virtual_space()->reserved_size() != 0;
176}
177
178#if INCLUDE_SERIALGC
179
180void PSOldGen::precompact() {
181 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
182
183 // Reset start array first.
184 start_array()->reset();
185
186 object_mark_sweep()->precompact();
187
188 // Now compact the young gen
189 heap->young_gen()->precompact();
190}
191
192void PSOldGen::adjust_pointers() {
193 object_mark_sweep()->adjust_pointers();
194}
195
196void PSOldGen::compact() {
197 object_mark_sweep()->compact(ZapUnusedHeapArea);
198}
199
200#endif // INCLUDE_SERIALGC
201
202size_t PSOldGen::contiguous_available() const {
203 return object_space()->free_in_bytes() + virtual_space()->uncommitted_size();
204}
205
206// Allocation. We report all successful allocations to the size policy
207// Note that the perm gen does not use this method, and should not!
208HeapWord* PSOldGen::allocate(size_t word_size) {
209 assert_locked_or_safepoint(Heap_lock);
210 HeapWord* res = allocate_noexpand(word_size);
211
212 if (res == NULL) {
213 res = expand_and_allocate(word_size);
214 }
215
216 // Allocations in the old generation need to be reported
217 if (res != NULL) {
218 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
219 heap->size_policy()->tenured_allocation(word_size * HeapWordSize);
220 }
221
222 return res;
223}
224
225HeapWord* PSOldGen::expand_and_allocate(size_t word_size) {
226 expand(word_size*HeapWordSize);
227 if (GCExpandToAllocateDelayMillis > 0) {
228 os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false);
229 }
230 return allocate_noexpand(word_size);
231}
232
233HeapWord* PSOldGen::expand_and_cas_allocate(size_t word_size) {
234 expand(word_size*HeapWordSize);
235 if (GCExpandToAllocateDelayMillis > 0) {
236 os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false);
237 }
238 return cas_allocate_noexpand(word_size);
239}
240
241void PSOldGen::expand(size_t bytes) {
242 if (bytes == 0) {
243 return;
244 }
245 MutexLocker x(ExpandHeap_lock);
246 const size_t alignment = virtual_space()->alignment();
247 size_t aligned_bytes = align_up(bytes, alignment);
248 size_t aligned_expand_bytes = align_up(MinHeapDeltaBytes, alignment);
249
250 if (UseNUMA) {
251 // With NUMA we use round-robin page allocation for the old gen. Expand by at least
252 // providing a page per lgroup. Alignment is larger or equal to the page size.
253 aligned_expand_bytes = MAX2(aligned_expand_bytes, alignment * os::numa_get_groups_num());
254 }
255 if (aligned_bytes == 0){
256 // The alignment caused the number of bytes to wrap. An expand_by(0) will
257 // return true with the implication that and expansion was done when it
258 // was not. A call to expand implies a best effort to expand by "bytes"
259 // but not a guarantee. Align down to give a best effort. This is likely
260 // the most that the generation can expand since it has some capacity to
261 // start with.
262 aligned_bytes = align_down(bytes, alignment);
263 }
264
265 bool success = false;
266 if (aligned_expand_bytes > aligned_bytes) {
267 success = expand_by(aligned_expand_bytes);
268 }
269 if (!success) {
270 success = expand_by(aligned_bytes);
271 }
272 if (!success) {
273 success = expand_to_reserved();
274 }
275
276 if (success && GCLocker::is_active_and_needs_gc()) {
277 log_debug(gc)("Garbage collection disabled, expanded heap instead");
278 }
279}
280
281bool PSOldGen::expand_by(size_t bytes) {
282 assert_lock_strong(ExpandHeap_lock);
283 assert_locked_or_safepoint(Heap_lock);
284 if (bytes == 0) {
285 return true; // That's what virtual_space()->expand_by(0) would return
286 }
287 bool result = virtual_space()->expand_by(bytes);
288 if (result) {
289 if (ZapUnusedHeapArea) {
290 // We need to mangle the newly expanded area. The memregion spans
291 // end -> new_end, we assume that top -> end is already mangled.
292 // Do the mangling before post_resize() is called because
293 // the space is available for allocation after post_resize();
294 HeapWord* const virtual_space_high = (HeapWord*) virtual_space()->high();
295 assert(object_space()->end() < virtual_space_high,
296 "Should be true before post_resize()");
297 MemRegion mangle_region(object_space()->end(), virtual_space_high);
298 // Note that the object space has not yet been updated to
299 // coincide with the new underlying virtual space.
300 SpaceMangler::mangle_region(mangle_region);
301 }
302 post_resize();
303 if (UsePerfData) {
304 _space_counters->update_capacity();
305 _gen_counters->update_all();
306 }
307 }
308
309 if (result) {
310 size_t new_mem_size = virtual_space()->committed_size();
311 size_t old_mem_size = new_mem_size - bytes;
312 log_debug(gc)("Expanding %s from " SIZE_FORMAT "K by " SIZE_FORMAT "K to " SIZE_FORMAT "K",
313 name(), old_mem_size/K, bytes/K, new_mem_size/K);
314 }
315
316 return result;
317}
318
319bool PSOldGen::expand_to_reserved() {
320 assert_lock_strong(ExpandHeap_lock);
321 assert_locked_or_safepoint(Heap_lock);
322
323 bool result = true;
324 const size_t remaining_bytes = virtual_space()->uncommitted_size();
325 if (remaining_bytes > 0) {
326 result = expand_by(remaining_bytes);
327 DEBUG_ONLY(if (!result) log_warning(gc)("grow to reserve failed"));
328 }
329 return result;
330}
331
332void PSOldGen::shrink(size_t bytes) {
333 assert_lock_strong(ExpandHeap_lock);
334 assert_locked_or_safepoint(Heap_lock);
335
336 size_t size = align_down(bytes, virtual_space()->alignment());
337 if (size > 0) {
338 assert_lock_strong(ExpandHeap_lock);
339 virtual_space()->shrink_by(bytes);
340 post_resize();
341
342 size_t new_mem_size = virtual_space()->committed_size();
343 size_t old_mem_size = new_mem_size + bytes;
344 log_debug(gc)("Shrinking %s from " SIZE_FORMAT "K by " SIZE_FORMAT "K to " SIZE_FORMAT "K",
345 name(), old_mem_size/K, bytes/K, new_mem_size/K);
346 }
347}
348
349void PSOldGen::resize(size_t desired_free_space) {
350 const size_t alignment = virtual_space()->alignment();
351 const size_t size_before = virtual_space()->committed_size();
352 size_t new_size = used_in_bytes() + desired_free_space;
353 if (new_size < used_in_bytes()) {
354 // Overflowed the addition.
355 new_size = gen_size_limit();
356 }
357 // Adjust according to our min and max
358 new_size = MAX2(MIN2(new_size, gen_size_limit()), min_gen_size());
359
360 assert(gen_size_limit() >= reserved().byte_size(), "max new size problem?");
361 new_size = align_up(new_size, alignment);
362
363 const size_t current_size = capacity_in_bytes();
364
365 log_trace(gc, ergo)("AdaptiveSizePolicy::old generation size: "
366 "desired free: " SIZE_FORMAT " used: " SIZE_FORMAT
367 " new size: " SIZE_FORMAT " current size " SIZE_FORMAT
368 " gen limits: " SIZE_FORMAT " / " SIZE_FORMAT,
369 desired_free_space, used_in_bytes(), new_size, current_size,
370 gen_size_limit(), min_gen_size());
371
372 if (new_size == current_size) {
373 // No change requested
374 return;
375 }
376 if (new_size > current_size) {
377 size_t change_bytes = new_size - current_size;
378 expand(change_bytes);
379 } else {
380 size_t change_bytes = current_size - new_size;
381 // shrink doesn't grab this lock, expand does. Is that right?
382 MutexLocker x(ExpandHeap_lock);
383 shrink(change_bytes);
384 }
385
386 log_trace(gc, ergo)("AdaptiveSizePolicy::old generation size: collection: %d (" SIZE_FORMAT ") -> (" SIZE_FORMAT ") ",
387 ParallelScavengeHeap::heap()->total_collections(),
388 size_before,
389 virtual_space()->committed_size());
390}
391
392// NOTE! We need to be careful about resizing. During a GC, multiple
393// allocators may be active during heap expansion. If we allow the
394// heap resizing to become visible before we have correctly resized
395// all heap related data structures, we may cause program failures.
396void PSOldGen::post_resize() {
397 // First construct a memregion representing the new size
398 MemRegion new_memregion((HeapWord*)virtual_space()->low(),
399 (HeapWord*)virtual_space()->high());
400 size_t new_word_size = new_memregion.word_size();
401
402 start_array()->set_covered_region(new_memregion);
403 ParallelScavengeHeap::heap()->card_table()->resize_covered_region(new_memregion);
404
405 // ALWAYS do this last!!
406 object_space()->initialize(new_memregion,
407 SpaceDecorator::DontClear,
408 SpaceDecorator::DontMangle);
409
410 assert(new_word_size == heap_word_size(object_space()->capacity_in_bytes()),
411 "Sanity");
412}
413
414size_t PSOldGen::gen_size_limit() {
415 return _max_gen_size;
416}
417
418void PSOldGen::reset_after_change() {
419 ShouldNotReachHere();
420 return;
421}
422
423size_t PSOldGen::available_for_expansion() {
424 ShouldNotReachHere();
425 return 0;
426}
427
428size_t PSOldGen::available_for_contraction() {
429 ShouldNotReachHere();
430 return 0;
431}
432
433void PSOldGen::print() const { print_on(tty);}
434void PSOldGen::print_on(outputStream* st) const {
435 st->print(" %-15s", name());
436 st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K",
437 capacity_in_bytes()/K, used_in_bytes()/K);
438 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")",
439 p2i(virtual_space()->low_boundary()),
440 p2i(virtual_space()->high()),
441 p2i(virtual_space()->high_boundary()));
442
443 st->print(" object"); object_space()->print_on(st);
444}
445
446void PSOldGen::print_used_change(size_t prev_used) const {
447 log_info(gc, heap)("%s: " SIZE_FORMAT "K->" SIZE_FORMAT "K(" SIZE_FORMAT "K)",
448 name(), prev_used / K, used_in_bytes() / K, capacity_in_bytes() / K);
449}
450
451void PSOldGen::update_counters() {
452 if (UsePerfData) {
453 _space_counters->update_all();
454 _gen_counters->update_all();
455 }
456}
457
458#ifndef PRODUCT
459
460void PSOldGen::space_invariants() {
461 assert(object_space()->end() == (HeapWord*) virtual_space()->high(),
462 "Space invariant");
463 assert(object_space()->bottom() == (HeapWord*) virtual_space()->low(),
464 "Space invariant");
465 assert(virtual_space()->low_boundary() <= virtual_space()->low(),
466 "Space invariant");
467 assert(virtual_space()->high_boundary() >= virtual_space()->high(),
468 "Space invariant");
469 assert(virtual_space()->low_boundary() == (char*) _reserved.start(),
470 "Space invariant");
471 assert(virtual_space()->high_boundary() == (char*) _reserved.end(),
472 "Space invariant");
473 assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(),
474 "Space invariant");
475}
476#endif
477
478void PSOldGen::verify() {
479 object_space()->verify();
480}
481class VerifyObjectStartArrayClosure : public ObjectClosure {
482 PSOldGen* _old_gen;
483 ObjectStartArray* _start_array;
484
485 public:
486 VerifyObjectStartArrayClosure(PSOldGen* old_gen, ObjectStartArray* start_array) :
487 _old_gen(old_gen), _start_array(start_array) { }
488
489 virtual void do_object(oop obj) {
490 HeapWord* test_addr = (HeapWord*)obj + 1;
491 guarantee(_start_array->object_start(test_addr) == (HeapWord*)obj, "ObjectStartArray cannot find start of object");
492 guarantee(_start_array->is_block_allocated((HeapWord*)obj), "ObjectStartArray missing block allocation");
493 }
494};
495
496void PSOldGen::verify_object_start_array() {
497 VerifyObjectStartArrayClosure check( this, &_start_array );
498 object_iterate(&check);
499}
500
501#ifndef PRODUCT
502void PSOldGen::record_spaces_top() {
503 assert(ZapUnusedHeapArea, "Not mangling unused space");
504 object_space()->set_top_for_allocations();
505}
506#endif
507