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
139 if (_object_space == NULL)
140 vm_exit_during_initialization("Could not allocate an old gen space");
141
142 object_space()->initialize(cmr,
143 SpaceDecorator::Clear,
144 SpaceDecorator::Mangle);
145
146 // Update the start_array
147 start_array()->set_covered_region(cmr);
148 }
149
150 void PSOldGen::initialize_performance_counters(const char* perf_data_name, int level) {
151 // Generation Counters, generation 'level', 1 subspace
152 _gen_counters = new PSGenerationCounters(perf_data_name, level, 1, _min_gen_size,
153 _max_gen_size, virtual_space());
154 _space_counters = new SpaceCounters(perf_data_name, 0,
155 virtual_space()->reserved_size(),
156 _object_space, _gen_counters);
157 }
158
159 // Assume that the generation has been allocated if its
160 // reserved size is not 0.
161 bool PSOldGen::is_allocated() {
162 return virtual_space()->reserved_size() != 0;
163 }
164
165 size_t PSOldGen::contiguous_available() const {
166 return object_space()->free_in_bytes() + virtual_space()->uncommitted_size();
167 }
168
169 // Allocation. We report all successful allocations to the size policy
170 // Note that the perm gen does not use this method, and should not!
171 HeapWord* PSOldGen::allocate(size_t word_size) {
172 assert_locked_or_safepoint(Heap_lock);
173 HeapWord* res = allocate_noexpand(word_size);
174
175 if (res == NULL) {
176 res = expand_and_allocate(word_size);
177 }
178
179 // Allocations in the old generation need to be reported
180 if (res != NULL) {
181 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
182 heap->size_policy()->tenured_allocation(word_size * HeapWordSize);
183 }
184
185 return res;
186 }
187
188 HeapWord* PSOldGen::expand_and_allocate(size_t word_size) {
189 expand(word_size*HeapWordSize);
190 if (GCExpandToAllocateDelayMillis > 0) {
191 os::naked_sleep(GCExpandToAllocateDelayMillis);
192 }
193 return allocate_noexpand(word_size);
194 }
195
196 HeapWord* PSOldGen::expand_and_cas_allocate(size_t word_size) {
197 expand(word_size*HeapWordSize);
198 if (GCExpandToAllocateDelayMillis > 0) {
199 os::naked_sleep(GCExpandToAllocateDelayMillis);
200 }
201 return cas_allocate_noexpand(word_size);
202 }
203
204 void PSOldGen::expand(size_t bytes) {
205 if (bytes == 0) {
206 return;
207 }
208 MutexLocker x(ExpandHeap_lock);
209 const size_t alignment = virtual_space()->alignment();
210 size_t aligned_bytes = align_up(bytes, alignment);
211 size_t aligned_expand_bytes = align_up(MinHeapDeltaBytes, alignment);
212
213 if (UseNUMA) {
214 // With NUMA we use round-robin page allocation for the old gen. Expand by at least
215 // providing a page per lgroup. Alignment is larger or equal to the page size.
216 aligned_expand_bytes = MAX2(aligned_expand_bytes, alignment * os::numa_get_groups_num());
217 }
218 if (aligned_bytes == 0){
219 // The alignment caused the number of bytes to wrap. An expand_by(0) will
220 // return true with the implication that and expansion was done when it
221 // was not. A call to expand implies a best effort to expand by "bytes"
222 // but not a guarantee. Align down to give a best effort. This is likely
223 // the most that the generation can expand since it has some capacity to
224 // start with.
225 aligned_bytes = align_down(bytes, alignment);
226 }
227
228 bool success = false;
229 if (aligned_expand_bytes > aligned_bytes) {
230 success = expand_by(aligned_expand_bytes);
231 }
232 if (!success) {
233 success = expand_by(aligned_bytes);
234 }
235 if (!success) {
236 success = expand_to_reserved();
237 }
238
239 if (success && GCLocker::is_active_and_needs_gc()) {
240 log_debug(gc)("Garbage collection disabled, expanded heap instead");
241 }
242 }
243
244 bool PSOldGen::expand_by(size_t bytes) {
245 assert_lock_strong(ExpandHeap_lock);
246 assert_locked_or_safepoint(Heap_lock);
247 if (bytes == 0) {
248 return true; // That's what virtual_space()->expand_by(0) would return
249 }
250 bool result = virtual_space()->expand_by(bytes);
251 if (result) {
252 if (ZapUnusedHeapArea) {
253 // We need to mangle the newly expanded area. The memregion spans
254 // end -> new_end, we assume that top -> end is already mangled.
255 // Do the mangling before post_resize() is called because
256 // the space is available for allocation after post_resize();
257 HeapWord* const virtual_space_high = (HeapWord*) virtual_space()->high();
258 assert(object_space()->end() < virtual_space_high,
259 "Should be true before post_resize()");
260 MemRegion mangle_region(object_space()->end(), virtual_space_high);
261 // Note that the object space has not yet been updated to
262 // coincide with the new underlying virtual space.
263 SpaceMangler::mangle_region(mangle_region);
264 }
265 post_resize();
266 if (UsePerfData) {
267 _space_counters->update_capacity();
268 _gen_counters->update_all();
269 }
270 }
271
272 if (result) {
273 size_t new_mem_size = virtual_space()->committed_size();
274 size_t old_mem_size = new_mem_size - bytes;
275 log_debug(gc)("Expanding %s from " SIZE_FORMAT "K by " SIZE_FORMAT "K to " SIZE_FORMAT "K",
276 name(), old_mem_size/K, bytes/K, new_mem_size/K);
277 }
278
279 return result;
280 }
281
282 bool PSOldGen::expand_to_reserved() {
283 assert_lock_strong(ExpandHeap_lock);
284 assert_locked_or_safepoint(Heap_lock);
285
286 bool result = true;
287 const size_t remaining_bytes = virtual_space()->uncommitted_size();
288 if (remaining_bytes > 0) {
289 result = expand_by(remaining_bytes);
290 DEBUG_ONLY(if (!result) log_warning(gc)("grow to reserve failed"));
291 }
292 return result;
293 }
294
295 void PSOldGen::shrink(size_t bytes) {
296 assert_lock_strong(ExpandHeap_lock);
297 assert_locked_or_safepoint(Heap_lock);
298
299 size_t size = align_down(bytes, virtual_space()->alignment());
300 if (size > 0) {
301 assert_lock_strong(ExpandHeap_lock);
302 virtual_space()->shrink_by(bytes);
303 post_resize();
304
305 size_t new_mem_size = virtual_space()->committed_size();
306 size_t old_mem_size = new_mem_size + bytes;
307 log_debug(gc)("Shrinking %s from " SIZE_FORMAT "K by " SIZE_FORMAT "K to " SIZE_FORMAT "K",
308 name(), old_mem_size/K, bytes/K, new_mem_size/K);
309 }
310 }
311
312 void PSOldGen::resize(size_t desired_free_space) {
313 const size_t alignment = virtual_space()->alignment();
314 const size_t size_before = virtual_space()->committed_size();
315 size_t new_size = used_in_bytes() + desired_free_space;
316 if (new_size < used_in_bytes()) {
317 // Overflowed the addition.
318 new_size = gen_size_limit();
319 }
320 // Adjust according to our min and max
321 new_size = clamp(new_size, min_gen_size(), gen_size_limit());
322
323 assert(gen_size_limit() >= reserved().byte_size(), "max new size problem?");
324 new_size = align_up(new_size, alignment);
325
326 const size_t current_size = capacity_in_bytes();
327
328 log_trace(gc, ergo)("AdaptiveSizePolicy::old generation size: "
329 "desired free: " SIZE_FORMAT " used: " SIZE_FORMAT
330 " new size: " SIZE_FORMAT " current size " SIZE_FORMAT
331 " gen limits: " SIZE_FORMAT " / " SIZE_FORMAT,
332 desired_free_space, used_in_bytes(), new_size, current_size,
333 gen_size_limit(), min_gen_size());
334
335 if (new_size == current_size) {
336 // No change requested
337 return;
338 }
339 if (new_size > current_size) {
340 size_t change_bytes = new_size - current_size;
341 expand(change_bytes);
342 } else {
343 size_t change_bytes = current_size - new_size;
344 // shrink doesn't grab this lock, expand does. Is that right?
345 MutexLocker x(ExpandHeap_lock);
346 shrink(change_bytes);
347 }
348
349 log_trace(gc, ergo)("AdaptiveSizePolicy::old generation size: collection: %d (" SIZE_FORMAT ") -> (" SIZE_FORMAT ") ",
350 ParallelScavengeHeap::heap()->total_collections(),
351 size_before,
352 virtual_space()->committed_size());
353 }
354
355 // NOTE! We need to be careful about resizing. During a GC, multiple
356 // allocators may be active during heap expansion. If we allow the
357 // heap resizing to become visible before we have correctly resized
358 // all heap related data structures, we may cause program failures.
359 void PSOldGen::post_resize() {
360 // First construct a memregion representing the new size
361 MemRegion new_memregion((HeapWord*)virtual_space()->low(),
362 (HeapWord*)virtual_space()->high());
363 size_t new_word_size = new_memregion.word_size();
364
365 start_array()->set_covered_region(new_memregion);
366 ParallelScavengeHeap::heap()->card_table()->resize_covered_region(new_memregion);
367
368 // ALWAYS do this last!!
369 object_space()->initialize(new_memregion,
370 SpaceDecorator::DontClear,
371 SpaceDecorator::DontMangle);
372
373 assert(new_word_size == heap_word_size(object_space()->capacity_in_bytes()),
374 "Sanity");
375 }
376
377 size_t PSOldGen::gen_size_limit() {
378 return _max_gen_size;
379 }
380
381 void PSOldGen::reset_after_change() {
382 ShouldNotReachHere();
383 return;
384 }
385
386 size_t PSOldGen::available_for_expansion() {
387 ShouldNotReachHere();
388 return 0;
389 }
390
391 size_t PSOldGen::available_for_contraction() {
392 ShouldNotReachHere();
393 return 0;
394 }
395
396 void PSOldGen::print() const { print_on(tty);}
397 void PSOldGen::print_on(outputStream* st) const {
398 st->print(" %-15s", name());
399 st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K",
400 capacity_in_bytes()/K, used_in_bytes()/K);
401 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")",
402 p2i(virtual_space()->low_boundary()),
403 p2i(virtual_space()->high()),
404 p2i(virtual_space()->high_boundary()));
405
406 st->print(" object"); object_space()->print_on(st);
407 }
408
409 void PSOldGen::update_counters() {
410 if (UsePerfData) {
411 _space_counters->update_all();
412 _gen_counters->update_all();
413 }
414 }
415
416 #ifndef PRODUCT
417
418 void PSOldGen::space_invariants() {
419 assert(object_space()->end() == (HeapWord*) virtual_space()->high(),
420 "Space invariant");
421 assert(object_space()->bottom() == (HeapWord*) virtual_space()->low(),
422 "Space invariant");
423 assert(virtual_space()->low_boundary() <= virtual_space()->low(),
424 "Space invariant");
425 assert(virtual_space()->high_boundary() >= virtual_space()->high(),
426 "Space invariant");
427 assert(virtual_space()->low_boundary() == (char*) _reserved.start(),
428 "Space invariant");
429 assert(virtual_space()->high_boundary() == (char*) _reserved.end(),
430 "Space invariant");
431 assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(),
432 "Space invariant");
433 }
434 #endif
435
436 void PSOldGen::verify() {
437 object_space()->verify();
438 }
439 class VerifyObjectStartArrayClosure : public ObjectClosure {
440 PSOldGen* _old_gen;
441 ObjectStartArray* _start_array;
442
443 public:
444 VerifyObjectStartArrayClosure(PSOldGen* old_gen, ObjectStartArray* start_array) :
445 _old_gen(old_gen), _start_array(start_array) { }
446
447 virtual void do_object(oop obj) {
448 HeapWord* test_addr = cast_from_oop<HeapWord*>(obj) + 1;
449 guarantee(_start_array->object_start(test_addr) == cast_from_oop<HeapWord*>(obj), "ObjectStartArray cannot find start of object");
450 guarantee(_start_array->is_block_allocated(cast_from_oop<HeapWord*>(obj)), "ObjectStartArray missing block allocation");
451 }
452 };
453
454 void PSOldGen::verify_object_start_array() {
455 VerifyObjectStartArrayClosure check( this, &_start_array );
456 object_iterate(&check);
457 }
458
459 #ifndef PRODUCT
460 void PSOldGen::record_spaces_top() {
461 assert(ZapUnusedHeapArea, "Not mangling unused space");
462 object_space()->set_top_for_allocations();
463 }
464 #endif