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