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.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "gc/parallel/objectStartArray.inline.hpp"
27 #include "gc/parallel/parallelScavengeHeap.hpp"
28 #include "gc/parallel/psAdaptiveSizePolicy.hpp"
29 #include "gc/parallel/psCardTable.hpp"
30 #include "gc/parallel/psMarkSweepDecorator.hpp"
31 #include "gc/parallel/psOldGen.hpp"
32 #include "gc/shared/cardTableBarrierSet.hpp"
33 #include "gc/shared/gcLocker.hpp"
34 #include "gc/shared/spaceDecorator.hpp"
35 #include "logging/log.hpp"
36 #include "oops/oop.inline.hpp"
37 #include "runtime/java.hpp"
38 #include "utilities/align.hpp"
39
40 inline const char* PSOldGen::select_name() {
41 return UseParallelOldGC ? "ParOldGen" : "PSOldGen";
42 }
43
44 PSOldGen::PSOldGen(ReservedSpace rs, size_t alignment,
45 size_t initial_size, size_t min_size, size_t max_size,
46 const char* perf_data_name, int level):
47 _name(select_name()), _init_gen_size(initial_size), _min_gen_size(min_size),
48 _max_gen_size(max_size)
49 {
50 initialize(rs, alignment, perf_data_name, level);
51 }
52
53 PSOldGen::PSOldGen(size_t initial_size,
54 size_t min_size, size_t max_size,
55 const char* perf_data_name, int level):
56 _name(select_name()), _init_gen_size(initial_size), _min_gen_size(min_size),
57 _max_gen_size(max_size)
58 {}
59
60 void PSOldGen::initialize(ReservedSpace rs, size_t alignment,
61 const char* perf_data_name, int level) {
62 initialize_virtual_space(rs, alignment);
63 initialize_work(perf_data_name, level);
64
65 // The old gen can grow to gen_size_limit(). _reserve reflects only
66 // the current maximum that can be committed.
67 assert(_reserved.byte_size() <= gen_size_limit(), "Consistency check");
68
69 initialize_performance_counters(perf_data_name, level);
70 }
71
72 void PSOldGen::initialize_virtual_space(ReservedSpace rs, size_t alignment) {
73
74 _virtual_space = new PSVirtualSpace(rs, alignment);
75 if (os::has_nvdimm() && UseParallelOldGC) {
76 if (!_virtual_space->expand_by(_init_gen_size, _nvdimm_fd)) {
77 vm_exit_during_initialization("Could not reserve enough space for "
78 "object heap");
79 }
80 #if defined (_WINDOWS)
81 // Windows OS does not support incremental mapping for DAX (NVDIMM) File System
82 if (os::has_nvdimm()) {
83 os::close(os::nvdimm_fd());
84 }
85 #endif
86 os::set_nvdimm_heapbase((address)(_virtual_space->reserved_low_addr()));
87 os::set_dram_heapbase((address)((char*)_virtual_space->reserved_low_addr() + _max_gen_size));
88 } else {
89 if (!_virtual_space->expand_by(_init_gen_size)) {
90 vm_exit_during_initialization("Could not reserve enough space for "
91 "object heap");
92 }
93 }
94 }
95
96 void PSOldGen::initialize_work(const char* perf_data_name, int level) {
97 //
98 // Basic memory initialization
99 //
100
101 MemRegion limit_reserved((HeapWord*)virtual_space()->low_boundary(),
102 heap_word_size(_max_gen_size));
103 assert(limit_reserved.byte_size() == _max_gen_size,
104 "word vs bytes confusion");
105 //
106 // Object start stuff
107 //
108
109 start_array()->initialize(limit_reserved);
110
111 _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
112 (HeapWord*)virtual_space()->high_boundary());
113
114 //
115 // Card table stuff
116 //
117
118 MemRegion cmr((HeapWord*)virtual_space()->low(),
119 (HeapWord*)virtual_space()->high());
120 if (ZapUnusedHeapArea) {
121 // Mangle newly committed space immediately rather than
122 // waiting for the initialization of the space even though
123 // mangling is related to spaces. Doing it here eliminates
124 // the need to carry along information that a complete mangling
125 // (bottom to end) needs to be done.
126 SpaceMangler::mangle_region(cmr);
127 }
128
129 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
130 PSCardTable* ct = heap->card_table();
131 ct->resize_covered_region(cmr);
132
133 // Verify that the start and end of this generation is the start of a card.
134 // If this wasn't true, a single card could span more than one generation,
135 // which would cause problems when we commit/uncommit memory, and when we
136 // clear and dirty cards.
137 guarantee(ct->is_card_aligned(_reserved.start()), "generation must be card aligned");
138 if (_reserved.end() != heap->reserved_region().end()) {
139 // Don't check at the very end of the heap as we'll assert that we're probing off
140 // the end if we try.
141 guarantee(ct->is_card_aligned(_reserved.end()), "generation must be card aligned");
142 }
143
144 //
145 // ObjectSpace stuff
146 //
147
148 _object_space = new MutableSpace(virtual_space()->alignment());
149
150 if (_object_space == NULL)
151 vm_exit_during_initialization("Could not allocate an old gen space");
152
153 object_space()->initialize(cmr,
154 SpaceDecorator::Clear,
155 SpaceDecorator::Mangle);
156
157 #if INCLUDE_SERIALGC
158 _object_mark_sweep = new PSMarkSweepDecorator(_object_space, start_array(), MarkSweepDeadRatio);
159
160 if (_object_mark_sweep == NULL) {
161 vm_exit_during_initialization("Could not complete allocation of old generation");
162 }
163 #endif // INCLUDE_SERIALGC
164
165 // Update the start_array
166 start_array()->set_covered_region(cmr);
167 }
168
169 void PSOldGen::initialize_performance_counters(const char* perf_data_name, int level) {
170 // Generation Counters, generation 'level', 1 subspace
171 _gen_counters = new PSGenerationCounters(perf_data_name, level, 1, _min_gen_size,
172 _max_gen_size, virtual_space());
173 _space_counters = new SpaceCounters(perf_data_name, 0,
174 virtual_space()->reserved_size(),
175 _object_space, _gen_counters);
176 }
177
178 // Assume that the generation has been allocated if its
179 // reserved size is not 0.
180 bool PSOldGen::is_allocated() {
181 return virtual_space()->reserved_size() != 0;
182 }
183
184 #if INCLUDE_SERIALGC
185
186 void PSOldGen::precompact() {
187 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
188
189 // Reset start array first.
190 start_array()->reset();
191
192 object_mark_sweep()->precompact();
193
194 // Now compact the young gen
195 heap->young_gen()->precompact();
196 }
197
198 void PSOldGen::adjust_pointers() {
199 object_mark_sweep()->adjust_pointers();
200 }
201
202 void PSOldGen::compact() {
203 object_mark_sweep()->compact(ZapUnusedHeapArea);
204 }
205
206 #endif // INCLUDE_SERIALGC
207
208 size_t PSOldGen::contiguous_available() const {
209 return object_space()->free_in_bytes() + virtual_space()->uncommitted_size();
210 }
211
212 // Allocation. We report all successful allocations to the size policy
213 // Note that the perm gen does not use this method, and should not!
214 HeapWord* PSOldGen::allocate(size_t word_size) {
215 assert_locked_or_safepoint(Heap_lock);
216 HeapWord* res = allocate_noexpand(word_size);
217
218 if (res == NULL) {
219 res = expand_and_allocate(word_size);
220 }
221
222 // Allocations in the old generation need to be reported
223 if (res != NULL) {
224 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
225 heap->size_policy()->tenured_allocation(word_size * HeapWordSize);
226 }
227
228 return res;
229 }
230
231 HeapWord* PSOldGen::expand_and_allocate(size_t word_size) {
232 expand(word_size*HeapWordSize);
233 if (GCExpandToAllocateDelayMillis > 0) {
234 os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false);
235 }
236 return allocate_noexpand(word_size);
237 }
238
239 HeapWord* PSOldGen::expand_and_cas_allocate(size_t word_size) {
240 expand(word_size*HeapWordSize);
241 if (GCExpandToAllocateDelayMillis > 0) {
242 os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false);
243 }
244 return cas_allocate_noexpand(word_size);
245 }
246
247 void PSOldGen::expand(size_t bytes) {
248 if (bytes == 0) {
249 return;
250 }
251 MutexLocker x(ExpandHeap_lock);
252 const size_t alignment = virtual_space()->alignment();
253 size_t aligned_bytes = align_up(bytes, alignment);
254 size_t aligned_expand_bytes = align_up(MinHeapDeltaBytes, alignment);
255
256 if (UseNUMA) {
257 // With NUMA we use round-robin page allocation for the old gen. Expand by at least
258 // providing a page per lgroup. Alignment is larger or equal to the page size.
259 aligned_expand_bytes = MAX2(aligned_expand_bytes, alignment * os::numa_get_groups_num());
260 }
261 if (aligned_bytes == 0){
262 // The alignment caused the number of bytes to wrap. An expand_by(0) will
263 // return true with the implication that and expansion was done when it
264 // was not. A call to expand implies a best effort to expand by "bytes"
265 // but not a guarantee. Align down to give a best effort. This is likely
266 // the most that the generation can expand since it has some capacity to
267 // start with.
268 aligned_bytes = align_down(bytes, alignment);
269 }
270
271 bool success = false;
272 if (aligned_expand_bytes > aligned_bytes) {
273 success = expand_by(aligned_expand_bytes);
274 }
275 if (!success) {
276 success = expand_by(aligned_bytes);
277 }
278 if (!success) {
279 success = expand_to_reserved();
280 }
281
282 if (success && GCLocker::is_active_and_needs_gc()) {
283 log_debug(gc)("Garbage collection disabled, expanded heap instead");
284 }
285 }
286
287 bool PSOldGen::expand_by(size_t bytes) {
288 assert_lock_strong(ExpandHeap_lock);
289 assert_locked_or_safepoint(Heap_lock);
290 if (bytes == 0) {
291 return true; // That's what virtual_space()->expand_by(0) would return
292 }
293 bool result = false;
294 if (os::has_nvdimm() && UseParallelOldGC) {
295 result = virtual_space()->expand_by(bytes, nvdimm_fd());
296 } else {
297 result = virtual_space()->expand_by(bytes);
298 }
299 if (result) {
300 if (ZapUnusedHeapArea) {
301 // We need to mangle the newly expanded area. The memregion spans
302 // end -> new_end, we assume that top -> end is already mangled.
303 // Do the mangling before post_resize() is called because
304 // the space is available for allocation after post_resize();
305 HeapWord* const virtual_space_high = (HeapWord*) virtual_space()->high();
306 assert(object_space()->end() < virtual_space_high,
307 "Should be true before post_resize()");
308 MemRegion mangle_region(object_space()->end(), virtual_space_high);
309 // Note that the object space has not yet been updated to
310 // coincide with the new underlying virtual space.
311 SpaceMangler::mangle_region(mangle_region);
312 }
313 post_resize();
314 if (UsePerfData) {
315 _space_counters->update_capacity();
316 _gen_counters->update_all();
317 }
318 }
319
320 if (result) {
321 size_t new_mem_size = virtual_space()->committed_size();
322 size_t old_mem_size = new_mem_size - bytes;
323 log_debug(gc)("Expanding %s from " SIZE_FORMAT "K by " SIZE_FORMAT "K to " SIZE_FORMAT "K",
324 name(), old_mem_size/K, bytes/K, new_mem_size/K);
325 }
326
327 return result;
328 }
329
330 bool PSOldGen::expand_to_reserved() {
331 assert_lock_strong(ExpandHeap_lock);
332 assert_locked_or_safepoint(Heap_lock);
333
334 bool result = true;
335 const size_t remaining_bytes = virtual_space()->uncommitted_size();
336 if (remaining_bytes > 0) {
337 result = expand_by(remaining_bytes);
338 DEBUG_ONLY(if (!result) log_warning(gc)("grow to reserve failed"));
339 }
340 return result;
341 }
342
343 void PSOldGen::shrink(size_t bytes) {
344 assert_lock_strong(ExpandHeap_lock);
345 assert_locked_or_safepoint(Heap_lock);
346
347 size_t size = align_down(bytes, virtual_space()->alignment());
348 if (size > 0) {
349 assert_lock_strong(ExpandHeap_lock);
350 virtual_space()->shrink_by(bytes);
351 post_resize();
352
353 size_t new_mem_size = virtual_space()->committed_size();
354 size_t old_mem_size = new_mem_size + bytes;
355 log_debug(gc)("Shrinking %s from " SIZE_FORMAT "K by " SIZE_FORMAT "K to " SIZE_FORMAT "K",
356 name(), old_mem_size/K, bytes/K, new_mem_size/K);
357 }
358 }
359
360 void PSOldGen::resize(size_t desired_free_space) {
361 const size_t alignment = virtual_space()->alignment();
362 const size_t size_before = virtual_space()->committed_size();
363 size_t new_size = used_in_bytes() + desired_free_space;
364 if (new_size < used_in_bytes()) {
365 // Overflowed the addition.
366 new_size = gen_size_limit();
367 }
368 // Adjust according to our min and max
369 new_size = MAX2(MIN2(new_size, gen_size_limit()), min_gen_size());
370
371 assert(gen_size_limit() >= reserved().byte_size(), "max new size problem?");
372 new_size = align_up(new_size, alignment);
373
374 const size_t current_size = capacity_in_bytes();
375
376 log_trace(gc, ergo)("AdaptiveSizePolicy::old generation size: "
377 "desired free: " SIZE_FORMAT " used: " SIZE_FORMAT
378 " new size: " SIZE_FORMAT " current size " SIZE_FORMAT
379 " gen limits: " SIZE_FORMAT " / " SIZE_FORMAT,
380 desired_free_space, used_in_bytes(), new_size, current_size,
381 gen_size_limit(), min_gen_size());
382
383 if (new_size == current_size) {
384 // No change requested
385 return;
386 }
387 if (new_size > current_size) {
388 size_t change_bytes = new_size - current_size;
389 expand(change_bytes);
390 } else {
391 size_t change_bytes = current_size - new_size;
392 // shrink doesn't grab this lock, expand does. Is that right?
393 MutexLocker x(ExpandHeap_lock);
394 shrink(change_bytes);
395 }
396
397 log_trace(gc, ergo)("AdaptiveSizePolicy::old generation size: collection: %d (" SIZE_FORMAT ") -> (" SIZE_FORMAT ") ",
398 ParallelScavengeHeap::heap()->total_collections(),
399 size_before,
400 virtual_space()->committed_size());
401 }
402
403 // NOTE! We need to be careful about resizing. During a GC, multiple
404 // allocators may be active during heap expansion. If we allow the
405 // heap resizing to become visible before we have correctly resized
406 // all heap related data structures, we may cause program failures.
407 void PSOldGen::post_resize() {
408 // First construct a memregion representing the new size
409 MemRegion new_memregion((HeapWord*)virtual_space()->low(),
410 (HeapWord*)virtual_space()->high());
411 size_t new_word_size = new_memregion.word_size();
412
413 start_array()->set_covered_region(new_memregion);
414 ParallelScavengeHeap::heap()->card_table()->resize_covered_region(new_memregion);
415
416 // ALWAYS do this last!!
417 object_space()->initialize(new_memregion,
418 SpaceDecorator::DontClear,
419 SpaceDecorator::DontMangle);
420
421 assert(new_word_size == heap_word_size(object_space()->capacity_in_bytes()),
422 "Sanity");
423 }
424
425 size_t PSOldGen::gen_size_limit() {
426 return _max_gen_size;
427 }
428
429 void PSOldGen::reset_after_change() {
430 ShouldNotReachHere();
431 return;
432 }
433
434 size_t PSOldGen::available_for_expansion() {
435 ShouldNotReachHere();
436 return 0;
437 }
438
439 size_t PSOldGen::available_for_contraction() {
440 ShouldNotReachHere();
441 return 0;
442 }
443
444 void PSOldGen::print() const { print_on(tty);}
445 void PSOldGen::print_on(outputStream* st) const {
446 st->print(" %-15s", name());
447 st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K",
448 capacity_in_bytes()/K, used_in_bytes()/K);
449 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")",
450 p2i(virtual_space()->low_boundary()),
451 p2i(virtual_space()->high()),
452 p2i(virtual_space()->high_boundary()));
453
454 st->print(" object"); object_space()->print_on(st);
455 }
456
457 void PSOldGen::print_used_change(size_t prev_used) const {
458 log_info(gc, heap)("%s: " SIZE_FORMAT "K->" SIZE_FORMAT "K(" SIZE_FORMAT "K)",
459 name(), prev_used / K, used_in_bytes() / K, capacity_in_bytes() / K);
460 }
461
462 void PSOldGen::update_counters() {
463 if (UsePerfData) {
464 _space_counters->update_all();
465 _gen_counters->update_all();
466 }
467 }
468
469 #ifndef PRODUCT
470
471 void PSOldGen::space_invariants() {
472 assert(object_space()->end() == (HeapWord*) virtual_space()->high(),
473 "Space invariant");
474 assert(object_space()->bottom() == (HeapWord*) virtual_space()->low(),
475 "Space invariant");
476 assert(virtual_space()->low_boundary() <= virtual_space()->low(),
477 "Space invariant");
478 assert(virtual_space()->high_boundary() >= virtual_space()->high(),
479 "Space invariant");
480 assert(virtual_space()->low_boundary() == (char*) _reserved.start(),
481 "Space invariant");
482 assert(virtual_space()->high_boundary() == (char*) _reserved.end(),
483 "Space invariant");
484 assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(),
485 "Space invariant");
486 }
487 #endif
488
489 void PSOldGen::verify() {
490 object_space()->verify();
491 }
492 class VerifyObjectStartArrayClosure : public ObjectClosure {
493 PSOldGen* _old_gen;
494 ObjectStartArray* _start_array;
495
496 public:
497 VerifyObjectStartArrayClosure(PSOldGen* old_gen, ObjectStartArray* start_array) :
498 _old_gen(old_gen), _start_array(start_array) { }
499
500 virtual void do_object(oop obj) {
501 HeapWord* test_addr = (HeapWord*)obj + 1;
502 guarantee(_start_array->object_start(test_addr) == (HeapWord*)obj, "ObjectStartArray cannot find start of object");
503 guarantee(_start_array->is_block_allocated((HeapWord*)obj), "ObjectStartArray missing block allocation");
504 }
505 };
506
507 void PSOldGen::verify_object_start_array() {
508 VerifyObjectStartArrayClosure check( this, &_start_array );
509 object_iterate(&check);
510 }
511
512 #ifndef PRODUCT
513 void PSOldGen::record_spaces_top() {
514 assert(ZapUnusedHeapArea, "Not mangling unused space");
515 object_space()->set_top_for_allocations();
516 }
517 #endif