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 (!_virtual_space->expand_by(_init_gen_size)) {
76 vm_exit_during_initialization("Could not reserve enough space for "
77 "object heap");
78 }
79 }
80
81 void PSOldGen::initialize_work(const char* perf_data_name, int level) {
82 //
83 // Basic memory initialization
84 //
85
86 MemRegion limit_reserved((HeapWord*)virtual_space()->low_boundary(),
87 heap_word_size(_max_gen_size));
88 assert(limit_reserved.byte_size() == _max_gen_size,
89 "word vs bytes confusion");
90 //
91 // Object start stuff
92 //
93
94 start_array()->initialize(limit_reserved);
95
96 _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
97 (HeapWord*)virtual_space()->high_boundary());
98
99 //
100 // Card table stuff
101 //
102
103 MemRegion cmr((HeapWord*)virtual_space()->low(),
104 (HeapWord*)virtual_space()->high());
105 if (ZapUnusedHeapArea) {
106 // Mangle newly committed space immediately rather than
107 // waiting for the initialization of the space even though
108 // mangling is related to spaces. Doing it here eliminates
109 // the need to carry along information that a complete mangling
110 // (bottom to end) needs to be done.
111 SpaceMangler::mangle_region(cmr);
112 }
113
114 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
115 PSCardTable* ct = heap->card_table();
116 ct->resize_covered_region(cmr);
117
118 // Verify that the start and end of this generation is the start of a card.
119 // If this wasn't true, a single card could span more than one generation,
120 // which would cause problems when we commit/uncommit memory, and when we
121 // clear and dirty cards.
122 guarantee(ct->is_card_aligned(_reserved.start()), "generation must be card aligned");
123 if (_reserved.end() != heap->reserved_region().end()) {
124 // Don't check at the very end of the heap as we'll assert that we're probing off
125 // the end if we try.
126 guarantee(ct->is_card_aligned(_reserved.end()), "generation must be card aligned");
127 }
128
129 //
130 // ObjectSpace stuff
131 //
132
133 _object_space = new MutableSpace(virtual_space()->alignment());
134
135 if (_object_space == NULL)
136 vm_exit_during_initialization("Could not allocate an old gen space");
137
138 object_space()->initialize(cmr,
139 SpaceDecorator::Clear,
140 SpaceDecorator::Mangle);
141
142 #if INCLUDE_SERIALGC
143 _object_mark_sweep = new PSMarkSweepDecorator(_object_space, start_array(), MarkSweepDeadRatio);
144
145 if (_object_mark_sweep == NULL) {
146 vm_exit_during_initialization("Could not complete allocation of old generation");
147 }
148 #endif // INCLUDE_SERIALGC
149
150 // Update the start_array
151 start_array()->set_covered_region(cmr);
152 }
153
154 void PSOldGen::initialize_performance_counters(const char* perf_data_name, int level) {
155 // Generation Counters, generation 'level', 1 subspace
156 _gen_counters = new PSGenerationCounters(perf_data_name, level, 1, _min_gen_size,
157 _max_gen_size, virtual_space());
158 _space_counters = new SpaceCounters(perf_data_name, 0,
159 virtual_space()->reserved_size(),
160 _object_space, _gen_counters);
161 }
162
163 // Assume that the generation has been allocated if its
164 // reserved size is not 0.
165 bool PSOldGen::is_allocated() {
166 return virtual_space()->reserved_size() != 0;
167 }
168
169 #if INCLUDE_SERIALGC
170
171 void PSOldGen::precompact() {
172 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
173
174 // Reset start array first.
175 start_array()->reset();
176
177 object_mark_sweep()->precompact();
178
179 // Now compact the young gen
180 heap->young_gen()->precompact();
181 }
182
183 void PSOldGen::adjust_pointers() {
184 object_mark_sweep()->adjust_pointers();
185 }
186
187 void PSOldGen::compact() {
188 object_mark_sweep()->compact(ZapUnusedHeapArea);
189 }
190
191 #endif // INCLUDE_SERIALGC
192
193 size_t PSOldGen::contiguous_available() const {
194 return object_space()->free_in_bytes() + virtual_space()->uncommitted_size();
195 }
196
197 // Allocation. We report all successful allocations to the size policy
198 // Note that the perm gen does not use this method, and should not!
199 HeapWord* PSOldGen::allocate(size_t word_size) {
200 assert_locked_or_safepoint(Heap_lock);
201 HeapWord* res = allocate_noexpand(word_size);
202
203 if (res == NULL) {
204 res = expand_and_allocate(word_size);
205 }
206
207 // Allocations in the old generation need to be reported
208 if (res != NULL) {
209 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
210 heap->size_policy()->tenured_allocation(word_size * HeapWordSize);
211 }
212
213 return res;
214 }
215
216 HeapWord* PSOldGen::expand_and_allocate(size_t word_size) {
217 expand(word_size*HeapWordSize);
218 if (GCExpandToAllocateDelayMillis > 0) {
219 os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false);
220 }
221 return allocate_noexpand(word_size);
222 }
223
224 HeapWord* PSOldGen::expand_and_cas_allocate(size_t word_size) {
225 expand(word_size*HeapWordSize);
226 if (GCExpandToAllocateDelayMillis > 0) {
227 os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false);
228 }
229 return cas_allocate_noexpand(word_size);
230 }
231
232 void PSOldGen::expand(size_t bytes) {
233 if (bytes == 0) {
234 return;
235 }
236 MutexLocker x(ExpandHeap_lock);
237 const size_t alignment = virtual_space()->alignment();
238 size_t aligned_bytes = align_up(bytes, alignment);
239 size_t aligned_expand_bytes = align_up(MinHeapDeltaBytes, alignment);
240
241 if (UseNUMA) {
242 // With NUMA we use round-robin page allocation for the old gen. Expand by at least
243 // providing a page per lgroup. Alignment is larger or equal to the page size.
244 aligned_expand_bytes = MAX2(aligned_expand_bytes, alignment * os::numa_get_groups_num());
245 }
246 if (aligned_bytes == 0){
247 // The alignment caused the number of bytes to wrap. An expand_by(0) will
248 // return true with the implication that and expansion was done when it
249 // was not. A call to expand implies a best effort to expand by "bytes"
250 // but not a guarantee. Align down to give a best effort. This is likely
251 // the most that the generation can expand since it has some capacity to
252 // start with.
253 aligned_bytes = align_down(bytes, alignment);
254 }
255
256 bool success = false;
257 if (aligned_expand_bytes > aligned_bytes) {
258 success = expand_by(aligned_expand_bytes);
259 }
260 if (!success) {
261 success = expand_by(aligned_bytes);
262 }
263 if (!success) {
264 success = expand_to_reserved();
265 }
266
267 if (success && GCLocker::is_active_and_needs_gc()) {
268 log_debug(gc)("Garbage collection disabled, expanded heap instead");
269 }
270 }
271
272 bool PSOldGen::expand_by(size_t bytes) {
273 assert_lock_strong(ExpandHeap_lock);
274 assert_locked_or_safepoint(Heap_lock);
275 if (bytes == 0) {
276 return true; // That's what virtual_space()->expand_by(0) would return
277 }
278 bool result = virtual_space()->expand_by(bytes);
279 if (result) {
280 if (ZapUnusedHeapArea) {
281 // We need to mangle the newly expanded area. The memregion spans
282 // end -> new_end, we assume that top -> end is already mangled.
283 // Do the mangling before post_resize() is called because
284 // the space is available for allocation after post_resize();
285 HeapWord* const virtual_space_high = (HeapWord*) virtual_space()->high();
286 assert(object_space()->end() < virtual_space_high,
287 "Should be true before post_resize()");
288 MemRegion mangle_region(object_space()->end(), virtual_space_high);
289 // Note that the object space has not yet been updated to
290 // coincide with the new underlying virtual space.
291 SpaceMangler::mangle_region(mangle_region);
292 }
293 post_resize();
294 if (UsePerfData) {
295 _space_counters->update_capacity();
296 _gen_counters->update_all();
297 }
298 }
299
300 if (result) {
301 size_t new_mem_size = virtual_space()->committed_size();
302 size_t old_mem_size = new_mem_size - bytes;
303 log_debug(gc)("Expanding %s from " SIZE_FORMAT "K by " SIZE_FORMAT "K to " SIZE_FORMAT "K",
304 name(), old_mem_size/K, bytes/K, new_mem_size/K);
305 }
306
307 return result;
308 }
309
310 bool PSOldGen::expand_to_reserved() {
311 assert_lock_strong(ExpandHeap_lock);
312 assert_locked_or_safepoint(Heap_lock);
313
314 bool result = true;
315 const size_t remaining_bytes = virtual_space()->uncommitted_size();
316 if (remaining_bytes > 0) {
317 result = expand_by(remaining_bytes);
318 DEBUG_ONLY(if (!result) log_warning(gc)("grow to reserve failed"));
319 }
320 return result;
321 }
322
323 void PSOldGen::shrink(size_t bytes) {
324 assert_lock_strong(ExpandHeap_lock);
325 assert_locked_or_safepoint(Heap_lock);
326
327 size_t size = align_down(bytes, virtual_space()->alignment());
328 if (size > 0) {
329 assert_lock_strong(ExpandHeap_lock);
330 virtual_space()->shrink_by(bytes);
331 post_resize();
332
333 size_t new_mem_size = virtual_space()->committed_size();
334 size_t old_mem_size = new_mem_size + bytes;
335 log_debug(gc)("Shrinking %s from " SIZE_FORMAT "K by " SIZE_FORMAT "K to " SIZE_FORMAT "K",
336 name(), old_mem_size/K, bytes/K, new_mem_size/K);
337 }
338 }
339
340 void PSOldGen::resize(size_t desired_free_space) {
341 const size_t alignment = virtual_space()->alignment();
342 const size_t size_before = virtual_space()->committed_size();
343 size_t new_size = used_in_bytes() + desired_free_space;
344 if (new_size < used_in_bytes()) {
345 // Overflowed the addition.
346 new_size = gen_size_limit();
347 }
348 // Adjust according to our min and max
349 new_size = MAX2(MIN2(new_size, gen_size_limit()), min_gen_size());
350
351 assert(gen_size_limit() >= reserved().byte_size(), "max new size problem?");
352 new_size = align_up(new_size, alignment);
353
354 const size_t current_size = capacity_in_bytes();
355
356 log_trace(gc, ergo)("AdaptiveSizePolicy::old generation size: "
357 "desired free: " SIZE_FORMAT " used: " SIZE_FORMAT
358 " new size: " SIZE_FORMAT " current size " SIZE_FORMAT
359 " gen limits: " SIZE_FORMAT " / " SIZE_FORMAT,
360 desired_free_space, used_in_bytes(), new_size, current_size,
361 gen_size_limit(), min_gen_size());
362
363 if (new_size == current_size) {
364 // No change requested
365 return;
366 }
367 if (new_size > current_size) {
368 size_t change_bytes = new_size - current_size;
369 expand(change_bytes);
370 } else {
371 size_t change_bytes = current_size - new_size;
372 // shrink doesn't grab this lock, expand does. Is that right?
373 MutexLocker x(ExpandHeap_lock);
374 shrink(change_bytes);
375 }
376
377 log_trace(gc, ergo)("AdaptiveSizePolicy::old generation size: collection: %d (" SIZE_FORMAT ") -> (" SIZE_FORMAT ") ",
378 ParallelScavengeHeap::heap()->total_collections(),
379 size_before,
380 virtual_space()->committed_size());
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 ParallelScavengeHeap::heap()->card_table()->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 st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K",
428 capacity_in_bytes()/K, used_in_bytes()/K);
429 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")",
430 p2i(virtual_space()->low_boundary()),
431 p2i(virtual_space()->high()),
432 p2i(virtual_space()->high_boundary()));
433
434 st->print(" object"); object_space()->print_on(st);
435 }
436
437 void PSOldGen::print_used_change(size_t prev_used) const {
438 log_info(gc, heap)("%s: " SIZE_FORMAT "K->" SIZE_FORMAT "K(" SIZE_FORMAT "K)",
439 name(), prev_used / K, used_in_bytes() / K, capacity_in_bytes() / K);
440 }
441
442 void PSOldGen::update_counters() {
443 if (UsePerfData) {
444 _space_counters->update_all();
445 _gen_counters->update_all();
446 }
447 }
448
449 #ifndef PRODUCT
450
451 void PSOldGen::space_invariants() {
452 assert(object_space()->end() == (HeapWord*) virtual_space()->high(),
453 "Space invariant");
454 assert(object_space()->bottom() == (HeapWord*) virtual_space()->low(),
455 "Space invariant");
456 assert(virtual_space()->low_boundary() <= virtual_space()->low(),
457 "Space invariant");
458 assert(virtual_space()->high_boundary() >= virtual_space()->high(),
459 "Space invariant");
460 assert(virtual_space()->low_boundary() == (char*) _reserved.start(),
461 "Space invariant");
462 assert(virtual_space()->high_boundary() == (char*) _reserved.end(),
463 "Space invariant");
464 assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(),
465 "Space invariant");
466 }
467 #endif
468
469 void PSOldGen::verify() {
470 object_space()->verify();
471 }
472 class VerifyObjectStartArrayClosure : public ObjectClosure {
473 PSOldGen* _old_gen;
474 ObjectStartArray* _start_array;
475
476 public:
477 VerifyObjectStartArrayClosure(PSOldGen* old_gen, ObjectStartArray* start_array) :
478 _old_gen(old_gen), _start_array(start_array) { }
479
480 virtual void do_object(oop obj) {
481 HeapWord* test_addr = (HeapWord*)obj + 1;
482 guarantee(_start_array->object_start(test_addr) == (HeapWord*)obj, "ObjectStartArray cannot find start of object");
483 guarantee(_start_array->is_block_allocated((HeapWord*)obj), "ObjectStartArray missing block allocation");
484 }
485 };
486
487 void PSOldGen::verify_object_start_array() {
488 VerifyObjectStartArrayClosure check( this, &_start_array );
489 object_iterate(&check);
490 }
491
492 #ifndef PRODUCT
493 void PSOldGen::record_spaces_top() {
494 assert(ZapUnusedHeapArea, "Not mangling unused space");
495 object_space()->set_top_for_allocations();
496 }
497 #endif