1 /*
2 * Copyright (c) 2001, 2020, 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/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/psOldGen.hpp"
33 #include "gc/shared/cardTableBarrierSet.hpp"
34 #include "gc/shared/gcLocker.hpp"
35 #include "gc/shared/spaceDecorator.inline.hpp"
36 #include "logging/log.hpp"
37 #include "oops/oop.inline.hpp"
38 #include "runtime/java.hpp"
39 #include "utilities/align.hpp"
40
41 PSOldGen::PSOldGen(ReservedSpace rs, size_t alignment,
42 size_t initial_size, size_t min_size, size_t max_size,
43 const char* perf_data_name, int level):
44 _init_gen_size(initial_size), _min_gen_size(min_size),
45 _max_gen_size(max_size)
46 {
47 initialize(rs, alignment, perf_data_name, level);
48 }
49
50 PSOldGen::PSOldGen(size_t initial_size,
51 size_t min_size, size_t max_size,
52 const char* perf_data_name, int level):
53 _init_gen_size(initial_size), _min_gen_size(min_size),
54 _max_gen_size(max_size)
55 {}
56
57 void PSOldGen::initialize(ReservedSpace rs, size_t alignment,
58 const char* perf_data_name, int level) {
59 initialize_virtual_space(rs, alignment);
60 initialize_work(perf_data_name, level);
61
62 // The old gen can grow to gen_size_limit(). _reserve reflects only
63 // the current maximum that can be committed.
64 assert(_reserved.byte_size() <= gen_size_limit(), "Consistency check");
65
66 initialize_performance_counters(perf_data_name, level);
67 }
68
69 void PSOldGen::initialize_virtual_space(ReservedSpace rs, size_t alignment) {
70
71 if(ParallelArguments::is_heterogeneous_heap()) {
72 _virtual_space = new PSFileBackedVirtualSpace(rs, alignment, AllocateOldGenAt);
73 if (!(static_cast <PSFileBackedVirtualSpace*>(_virtual_space))->initialize()) {
74 vm_exit_during_initialization("Could not map space for PSOldGen at given AllocateOldGenAt path");
75 }
76 } else {
77 _virtual_space = new PSVirtualSpace(rs, alignment);
78 }
79 if (!_virtual_space->expand_by(_init_gen_size)) {
80 vm_exit_during_initialization("Could not reserve enough space for "
81 "object heap");
82 }
83 }
84
85 void PSOldGen::initialize_work(const char* perf_data_name, int level) {
86 //
87 // Basic memory initialization
88 //
89
90 MemRegion limit_reserved((HeapWord*)virtual_space()->low_boundary(),
91 heap_word_size(_max_gen_size));
92 assert(limit_reserved.byte_size() == _max_gen_size,
93 "word vs bytes confusion");
94 //
95 // Object start stuff
96 //
97
98 start_array()->initialize(limit_reserved);
99
100 _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
101 (HeapWord*)virtual_space()->high_boundary());
102
103 //
104 // Card table stuff
105 //
106
107 MemRegion cmr((HeapWord*)virtual_space()->low(),
108 (HeapWord*)virtual_space()->high());
109 if (ZapUnusedHeapArea) {
110 // Mangle newly committed space immediately rather than
111 // waiting for the initialization of the space even though
112 // mangling is related to spaces. Doing it here eliminates
113 // the need to carry along information that a complete mangling
114 // (bottom to end) needs to be done.
115 SpaceMangler::mangle_region(cmr);
116 }
117
118 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
119 PSCardTable* ct = heap->card_table();
120 ct->resize_covered_region(cmr);
121
122 // Verify that the start and end of this generation is the start of a card.
123 // If this wasn't true, a single card could span more than one generation,
124 // which would cause problems when we commit/uncommit memory, and when we
125 // clear and dirty cards.
126 guarantee(ct->is_card_aligned(_reserved.start()), "generation must be card aligned");
127 if (_reserved.end() != heap->reserved_region().end()) {
128 // Don't check at the very end of the heap as we'll assert that we're probing off
129 // the end if we try.
130 guarantee(ct->is_card_aligned(_reserved.end()), "generation must be card aligned");
131 }
132
133 //
134 // ObjectSpace stuff
135 //
136
137 _object_space = new MutableSpace(virtual_space()->alignment());
138 object_space()->initialize(cmr,
139 SpaceDecorator::Clear,
140 SpaceDecorator::Mangle);
141
142 // Update the start_array
143 start_array()->set_covered_region(cmr);
144 }
145
146 void PSOldGen::initialize_performance_counters(const char* perf_data_name, int level) {
147 // Generation Counters, generation 'level', 1 subspace
148 _gen_counters = new PSGenerationCounters(perf_data_name, level, 1, _min_gen_size,
149 _max_gen_size, virtual_space());
150 _space_counters = new SpaceCounters(perf_data_name, 0,
151 virtual_space()->reserved_size(),
152 _object_space, _gen_counters);
153 }
154
155 // Assume that the generation has been allocated if its
156 // reserved size is not 0.
157 bool PSOldGen::is_allocated() {
158 return virtual_space()->reserved_size() != 0;
159 }
160
161 size_t PSOldGen::contiguous_available() const {
162 return object_space()->free_in_bytes() + virtual_space()->uncommitted_size();
163 }
164
165 // Allocation. We report all successful allocations to the size policy
166 // Note that the perm gen does not use this method, and should not!
167 HeapWord* PSOldGen::allocate(size_t word_size) {
168 assert_locked_or_safepoint(Heap_lock);
169 HeapWord* res = allocate_noexpand(word_size);
170
171 if (res == NULL) {
172 res = expand_and_allocate(word_size);
173 }
174
175 // Allocations in the old generation need to be reported
176 if (res != NULL) {
177 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
178 heap->size_policy()->tenured_allocation(word_size * HeapWordSize);
179 }
180
181 return res;
182 }
183
184 HeapWord* PSOldGen::expand_and_allocate(size_t word_size) {
185 expand(word_size*HeapWordSize);
186 if (GCExpandToAllocateDelayMillis > 0) {
187 os::naked_sleep(GCExpandToAllocateDelayMillis);
188 }
189 return allocate_noexpand(word_size);
190 }
191
192 HeapWord* PSOldGen::expand_and_cas_allocate(size_t word_size) {
193 expand(word_size*HeapWordSize);
194 if (GCExpandToAllocateDelayMillis > 0) {
195 os::naked_sleep(GCExpandToAllocateDelayMillis);
196 }
197 return cas_allocate_noexpand(word_size);
198 }
199
200 void PSOldGen::expand(size_t bytes) {
201 if (bytes == 0) {
202 return;
203 }
204 MutexLocker x(ExpandHeap_lock);
205 const size_t alignment = virtual_space()->alignment();
206 size_t aligned_bytes = align_up(bytes, alignment);
207 size_t aligned_expand_bytes = align_up(MinHeapDeltaBytes, alignment);
208
209 if (UseNUMA) {
210 // With NUMA we use round-robin page allocation for the old gen. Expand by at least
211 // providing a page per lgroup. Alignment is larger or equal to the page size.
212 aligned_expand_bytes = MAX2(aligned_expand_bytes, alignment * os::numa_get_groups_num());
213 }
214 if (aligned_bytes == 0){
215 // The alignment caused the number of bytes to wrap. An expand_by(0) will
216 // return true with the implication that and expansion was done when it
217 // was not. A call to expand implies a best effort to expand by "bytes"
218 // but not a guarantee. Align down to give a best effort. This is likely
219 // the most that the generation can expand since it has some capacity to
220 // start with.
221 aligned_bytes = align_down(bytes, alignment);
222 }
223
224 bool success = false;
225 if (aligned_expand_bytes > aligned_bytes) {
226 success = expand_by(aligned_expand_bytes);
227 }
228 if (!success) {
229 success = expand_by(aligned_bytes);
230 }
231 if (!success) {
232 success = expand_to_reserved();
233 }
234
235 if (success && GCLocker::is_active_and_needs_gc()) {
236 log_debug(gc)("Garbage collection disabled, expanded heap instead");
237 }
238 }
239
240 bool PSOldGen::expand_by(size_t bytes) {
241 assert_lock_strong(ExpandHeap_lock);
242 assert_locked_or_safepoint(Heap_lock);
243 if (bytes == 0) {
244 return true; // That's what virtual_space()->expand_by(0) would return
245 }
246 bool result = virtual_space()->expand_by(bytes);
247 if (result) {
248 if (ZapUnusedHeapArea) {
249 // We need to mangle the newly expanded area. The memregion spans
250 // end -> new_end, we assume that top -> end is already mangled.
251 // Do the mangling before post_resize() is called because
252 // the space is available for allocation after post_resize();
253 HeapWord* const virtual_space_high = (HeapWord*) virtual_space()->high();
254 assert(object_space()->end() < virtual_space_high,
255 "Should be true before post_resize()");
256 MemRegion mangle_region(object_space()->end(), virtual_space_high);
257 // Note that the object space has not yet been updated to
258 // coincide with the new underlying virtual space.
259 SpaceMangler::mangle_region(mangle_region);
260 }
261 post_resize();
262 if (UsePerfData) {
263 _space_counters->update_capacity();
264 _gen_counters->update_all();
265 }
266 }
267
268 if (result) {
269 size_t new_mem_size = virtual_space()->committed_size();
270 size_t old_mem_size = new_mem_size - bytes;
271 log_debug(gc)("Expanding %s from " SIZE_FORMAT "K by " SIZE_FORMAT "K to " SIZE_FORMAT "K",
272 name(), old_mem_size/K, bytes/K, new_mem_size/K);
273 }
274
275 return result;
276 }
277
278 bool PSOldGen::expand_to_reserved() {
279 assert_lock_strong(ExpandHeap_lock);
280 assert_locked_or_safepoint(Heap_lock);
281
282 bool result = true;
283 const size_t remaining_bytes = virtual_space()->uncommitted_size();
284 if (remaining_bytes > 0) {
285 result = expand_by(remaining_bytes);
286 DEBUG_ONLY(if (!result) log_warning(gc)("grow to reserve failed"));
287 }
288 return result;
289 }
290
291 void PSOldGen::shrink(size_t bytes) {
292 assert_lock_strong(ExpandHeap_lock);
293 assert_locked_or_safepoint(Heap_lock);
294
295 size_t size = align_down(bytes, virtual_space()->alignment());
296 if (size > 0) {
297 assert_lock_strong(ExpandHeap_lock);
298 virtual_space()->shrink_by(bytes);
299 post_resize();
300
301 size_t new_mem_size = virtual_space()->committed_size();
302 size_t old_mem_size = new_mem_size + bytes;
303 log_debug(gc)("Shrinking %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
308 void PSOldGen::resize(size_t desired_free_space) {
309 const size_t alignment = virtual_space()->alignment();
310 const size_t size_before = virtual_space()->committed_size();
311 size_t new_size = used_in_bytes() + desired_free_space;
312 if (new_size < used_in_bytes()) {
313 // Overflowed the addition.
314 new_size = gen_size_limit();
315 }
316 // Adjust according to our min and max
317 new_size = clamp(new_size, min_gen_size(), gen_size_limit());
318
319 assert(gen_size_limit() >= reserved().byte_size(), "max new size problem?");
320 new_size = align_up(new_size, alignment);
321
322 const size_t current_size = capacity_in_bytes();
323
324 log_trace(gc, ergo)("AdaptiveSizePolicy::old generation size: "
325 "desired free: " SIZE_FORMAT " used: " SIZE_FORMAT
326 " new size: " SIZE_FORMAT " current size " SIZE_FORMAT
327 " gen limits: " SIZE_FORMAT " / " SIZE_FORMAT,
328 desired_free_space, used_in_bytes(), new_size, current_size,
329 gen_size_limit(), min_gen_size());
330
331 if (new_size == current_size) {
332 // No change requested
333 return;
334 }
335 if (new_size > current_size) {
336 size_t change_bytes = new_size - current_size;
337 expand(change_bytes);
338 } else {
339 size_t change_bytes = current_size - new_size;
340 // shrink doesn't grab this lock, expand does. Is that right?
341 MutexLocker x(ExpandHeap_lock);
342 shrink(change_bytes);
343 }
344
345 log_trace(gc, ergo)("AdaptiveSizePolicy::old generation size: collection: %d (" SIZE_FORMAT ") -> (" SIZE_FORMAT ") ",
346 ParallelScavengeHeap::heap()->total_collections(),
347 size_before,
348 virtual_space()->committed_size());
349 }
350
351 // NOTE! We need to be careful about resizing. During a GC, multiple
352 // allocators may be active during heap expansion. If we allow the
353 // heap resizing to become visible before we have correctly resized
354 // all heap related data structures, we may cause program failures.
355 void PSOldGen::post_resize() {
356 // First construct a memregion representing the new size
357 MemRegion new_memregion((HeapWord*)virtual_space()->low(),
358 (HeapWord*)virtual_space()->high());
359 size_t new_word_size = new_memregion.word_size();
360
361 start_array()->set_covered_region(new_memregion);
362 ParallelScavengeHeap::heap()->card_table()->resize_covered_region(new_memregion);
363
364 // ALWAYS do this last!!
365 object_space()->initialize(new_memregion,
366 SpaceDecorator::DontClear,
367 SpaceDecorator::DontMangle);
368
369 assert(new_word_size == heap_word_size(object_space()->capacity_in_bytes()),
370 "Sanity");
371 }
372
373 size_t PSOldGen::gen_size_limit() {
374 return _max_gen_size;
375 }
376
377 void PSOldGen::reset_after_change() {
378 ShouldNotReachHere();
379 return;
380 }
381
382 size_t PSOldGen::available_for_expansion() {
383 ShouldNotReachHere();
384 return 0;
385 }
386
387 size_t PSOldGen::available_for_contraction() {
388 ShouldNotReachHere();
389 return 0;
390 }
391
392 void PSOldGen::print() const { print_on(tty);}
393 void PSOldGen::print_on(outputStream* st) const {
394 st->print(" %-15s", name());
395 st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K",
396 capacity_in_bytes()/K, used_in_bytes()/K);
397 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")",
398 p2i(virtual_space()->low_boundary()),
399 p2i(virtual_space()->high()),
400 p2i(virtual_space()->high_boundary()));
401
402 st->print(" object"); object_space()->print_on(st);
403 }
404
405 void PSOldGen::update_counters() {
406 if (UsePerfData) {
407 _space_counters->update_all();
408 _gen_counters->update_all();
409 }
410 }
411
412 #ifndef PRODUCT
413
414 void PSOldGen::space_invariants() {
415 assert(object_space()->end() == (HeapWord*) virtual_space()->high(),
416 "Space invariant");
417 assert(object_space()->bottom() == (HeapWord*) virtual_space()->low(),
418 "Space invariant");
419 assert(virtual_space()->low_boundary() <= virtual_space()->low(),
420 "Space invariant");
421 assert(virtual_space()->high_boundary() >= virtual_space()->high(),
422 "Space invariant");
423 assert(virtual_space()->low_boundary() == (char*) _reserved.start(),
424 "Space invariant");
425 assert(virtual_space()->high_boundary() == (char*) _reserved.end(),
426 "Space invariant");
427 assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(),
428 "Space invariant");
429 }
430 #endif
431
432 void PSOldGen::verify() {
433 object_space()->verify();
434 }
435 class VerifyObjectStartArrayClosure : public ObjectClosure {
436 PSOldGen* _old_gen;
437 ObjectStartArray* _start_array;
438
439 public:
440 VerifyObjectStartArrayClosure(PSOldGen* old_gen, ObjectStartArray* start_array) :
441 _old_gen(old_gen), _start_array(start_array) { }
442
443 virtual void do_object(oop obj) {
444 HeapWord* test_addr = cast_from_oop<HeapWord*>(obj) + 1;
445 guarantee(_start_array->object_start(test_addr) == cast_from_oop<HeapWord*>(obj), "ObjectStartArray cannot find start of object");
446 guarantee(_start_array->is_block_allocated(cast_from_oop<HeapWord*>(obj)), "ObjectStartArray missing block allocation");
447 }
448 };
449
450 void PSOldGen::verify_object_start_array() {
451 VerifyObjectStartArrayClosure check( this, &_start_array );
452 object_iterate(&check);
453 }
454
455 #ifndef PRODUCT
456 void PSOldGen::record_spaces_top() {
457 assert(ZapUnusedHeapArea, "Not mangling unused space");
458 object_space()->set_top_for_allocations();
459 }
460 #endif