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