1 /*
2 * Copyright (c) 2001, 2016, 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/psMarkSweepDecorator.hpp"
30 #include "gc/parallel/psOldGen.hpp"
31 #include "gc/shared/cardTableModRefBS.hpp"
32 #include "gc/shared/gcLocker.inline.hpp"
33 #include "gc/shared/spaceDecorator.hpp"
34 #include "logging/log.hpp"
35 #include "oops/oop.inline.hpp"
36 #include "runtime/java.hpp"
37
38 inline const char* PSOldGen::select_name() {
39 return UseParallelOldGC ? "ParOldGen" : "PSOldGen";
40 }
41
42 PSOldGen::PSOldGen(ReservedSpace rs, size_t alignment,
43 size_t initial_size, size_t min_size, size_t max_size,
44 const char* perf_data_name, int level):
45 _name(select_name()), _init_gen_size(initial_size), _min_gen_size(min_size),
46 _max_gen_size(max_size)
47 {
48 initialize(rs, alignment, perf_data_name, level);
49 }
50
51 PSOldGen::PSOldGen(size_t initial_size,
52 size_t min_size, size_t max_size,
53 const char* perf_data_name, int level):
54 _name(select_name()), _init_gen_size(initial_size), _min_gen_size(min_size),
55 _max_gen_size(max_size)
56 {}
57
58 void PSOldGen::initialize(ReservedSpace rs, size_t alignment,
59 const char* perf_data_name, int level) {
60 initialize_virtual_space(rs, alignment);
61 initialize_work(perf_data_name, level);
62
63 // The old gen can grow to gen_size_limit(). _reserve reflects only
64 // the current maximum that can be committed.
65 assert(_reserved.byte_size() <= gen_size_limit(), "Consistency check");
66
67 initialize_performance_counters(perf_data_name, level);
68 }
69
70 void PSOldGen::initialize_virtual_space(ReservedSpace rs, size_t alignment) {
71
72 _virtual_space = new PSVirtualSpace(rs, alignment);
73 if (!_virtual_space->expand_by(_init_gen_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
115 ct->resize_covered_region(cmr);
116
117 // Verify that the start and end of this generation is the start of a card.
118 // If this wasn't true, a single card could span more than one generation,
119 // which would cause problems when we commit/uncommit memory, and when we
120 // clear and dirty cards.
121 guarantee(ct->is_card_aligned(_reserved.start()), "generation must be card aligned");
122 if (_reserved.end() != heap->reserved_region().end()) {
123 // Don't check at the very end of the heap as we'll assert that we're probing off
124 // the end if we try.
125 guarantee(ct->is_card_aligned(_reserved.end()), "generation must be card aligned");
126 }
127
128 //
129 // ObjectSpace stuff
130 //
131
132 _object_space = new MutableSpace(virtual_space()->alignment());
133
134 if (_object_space == NULL)
135 vm_exit_during_initialization("Could not allocate an old gen space");
136
137 object_space()->initialize(cmr,
138 SpaceDecorator::Clear,
139 SpaceDecorator::Mangle);
140
141 _object_mark_sweep = new PSMarkSweepDecorator(_object_space, start_array(), MarkSweepDeadRatio);
142
143 if (_object_mark_sweep == NULL)
144 vm_exit_during_initialization("Could not complete allocation of old generation");
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 void PSOldGen::precompact() {
166 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
167
168 // Reset start array first.
169 start_array()->reset();
170
171 object_mark_sweep()->precompact();
172
173 // Now compact the young gen
174 heap->young_gen()->precompact();
175 }
176
177 void PSOldGen::adjust_pointers() {
178 object_mark_sweep()->adjust_pointers();
179 }
180
181 void PSOldGen::compact() {
182 object_mark_sweep()->compact(ZapUnusedHeapArea);
183 }
184
185 size_t PSOldGen::contiguous_available() const {
186 return object_space()->free_in_bytes() + virtual_space()->uncommitted_size();
187 }
188
189 // Allocation. We report all successful allocations to the size policy
190 // Note that the perm gen does not use this method, and should not!
191 HeapWord* PSOldGen::allocate(size_t word_size) {
192 assert_locked_or_safepoint(Heap_lock);
193 HeapWord* res = allocate_noexpand(word_size);
194
195 if (res == NULL) {
196 res = expand_and_allocate(word_size);
197 }
198
199 // Allocations in the old generation need to be reported
200 if (res != NULL) {
201 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
202 heap->size_policy()->tenured_allocation(word_size * HeapWordSize);
203 }
204
205 return res;
206 }
207
208 HeapWord* PSOldGen::expand_and_allocate(size_t word_size) {
209 expand(word_size*HeapWordSize);
210 if (GCExpandToAllocateDelayMillis > 0) {
211 os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false);
212 }
213 return allocate_noexpand(word_size);
214 }
215
216 HeapWord* PSOldGen::expand_and_cas_allocate(size_t word_size) {
217 expand(word_size*HeapWordSize);
218 if (GCExpandToAllocateDelayMillis > 0) {
219 os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false);
220 }
221 return cas_allocate_noexpand(word_size);
222 }
223
224 void PSOldGen::expand(size_t bytes) {
225 if (bytes == 0) {
226 return;
227 }
228 MutexLocker x(ExpandHeap_lock);
229 const size_t alignment = virtual_space()->alignment();
230 size_t aligned_bytes = align_size_up(bytes, alignment);
231 size_t aligned_expand_bytes = align_size_up(MinHeapDeltaBytes, alignment);
232
233 if (UseNUMA) {
234 // With NUMA we use round-robin page allocation for the old gen. Expand by at least
235 // providing a page per lgroup. Alignment is larger or equal to the page size.
236 aligned_expand_bytes = MAX2(aligned_expand_bytes, alignment * os::numa_get_groups_num());
237 }
238 if (aligned_bytes == 0){
239 // The alignment caused the number of bytes to wrap. An expand_by(0) will
240 // return true with the implication that and expansion was done when it
241 // was not. A call to expand implies a best effort to expand by "bytes"
242 // but not a guarantee. Align down to give a best effort. This is likely
243 // the most that the generation can expand since it has some capacity to
244 // start with.
245 aligned_bytes = align_size_down(bytes, alignment);
246 }
247
248 bool success = false;
249 if (aligned_expand_bytes > aligned_bytes) {
250 success = expand_by(aligned_expand_bytes);
251 }
252 if (!success) {
253 success = expand_by(aligned_bytes);
254 }
255 if (!success) {
256 success = expand_to_reserved();
257 }
258
259 if (success && GCLocker::is_active_and_needs_gc()) {
260 log_debug(gc)("Garbage collection disabled, expanded heap instead");
261 }
262 }
263
264 bool PSOldGen::expand_by(size_t bytes) {
265 assert_lock_strong(ExpandHeap_lock);
266 assert_locked_or_safepoint(Heap_lock);
267 if (bytes == 0) {
268 return true; // That's what virtual_space()->expand_by(0) would return
269 }
270 bool result = virtual_space()->expand_by(bytes);
271 if (result) {
272 if (ZapUnusedHeapArea) {
273 // We need to mangle the newly expanded area. The memregion spans
274 // end -> new_end, we assume that top -> end is already mangled.
275 // Do the mangling before post_resize() is called because
276 // the space is available for allocation after post_resize();
277 HeapWord* const virtual_space_high = (HeapWord*) virtual_space()->high();
278 assert(object_space()->end() < virtual_space_high,
279 "Should be true before post_resize()");
280 MemRegion mangle_region(object_space()->end(), virtual_space_high);
281 // Note that the object space has not yet been updated to
282 // coincide with the new underlying virtual space.
283 SpaceMangler::mangle_region(mangle_region);
284 }
285 post_resize();
286 if (UsePerfData) {
287 _space_counters->update_capacity();
288 _gen_counters->update_all();
289 }
290 }
291
292 if (result) {
293 size_t new_mem_size = virtual_space()->committed_size();
294 size_t old_mem_size = new_mem_size - bytes;
295 log_debug(gc)("Expanding %s from " SIZE_FORMAT "K by " SIZE_FORMAT "K to " SIZE_FORMAT "K",
296 name(), old_mem_size/K, bytes/K, new_mem_size/K);
297 }
298
299 return result;
300 }
301
302 bool PSOldGen::expand_to_reserved() {
303 assert_lock_strong(ExpandHeap_lock);
304 assert_locked_or_safepoint(Heap_lock);
305
306 bool result = true;
307 const size_t remaining_bytes = virtual_space()->uncommitted_size();
308 if (remaining_bytes > 0) {
309 result = expand_by(remaining_bytes);
310 DEBUG_ONLY(if (!result) log_warning(gc)("grow to reserve failed"));
311 }
312 return result;
313 }
314
315 void PSOldGen::shrink(size_t bytes) {
316 assert_lock_strong(ExpandHeap_lock);
317 assert_locked_or_safepoint(Heap_lock);
318
319 size_t size = align_size_down(bytes, virtual_space()->alignment());
320 if (size > 0) {
321 assert_lock_strong(ExpandHeap_lock);
322 virtual_space()->shrink_by(bytes);
323 post_resize();
324
325 size_t new_mem_size = virtual_space()->committed_size();
326 size_t old_mem_size = new_mem_size + bytes;
327 log_debug(gc)("Shrinking %s from " SIZE_FORMAT "K by " SIZE_FORMAT "K to " SIZE_FORMAT "K",
328 name(), old_mem_size/K, bytes/K, new_mem_size/K);
329 }
330 }
331
332 void PSOldGen::resize(size_t desired_free_space) {
333 const size_t alignment = virtual_space()->alignment();
334 const size_t size_before = virtual_space()->committed_size();
335 size_t new_size = used_in_bytes() + desired_free_space;
336 if (new_size < used_in_bytes()) {
337 // Overflowed the addition.
338 new_size = gen_size_limit();
339 }
340 // Adjust according to our min and max
341 new_size = MAX2(MIN2(new_size, gen_size_limit()), min_gen_size());
342
343 assert(gen_size_limit() >= reserved().byte_size(), "max new size problem?");
344 new_size = align_size_up(new_size, alignment);
345
346 const size_t current_size = capacity_in_bytes();
347
348 log_trace(gc, ergo)("AdaptiveSizePolicy::old generation size: "
349 "desired free: " SIZE_FORMAT " used: " SIZE_FORMAT
350 " new size: " SIZE_FORMAT " current size " SIZE_FORMAT
351 " gen limits: " SIZE_FORMAT " / " SIZE_FORMAT,
352 desired_free_space, used_in_bytes(), new_size, current_size,
353 gen_size_limit(), min_gen_size());
354
355 if (new_size == current_size) {
356 // No change requested
357 return;
358 }
359 if (new_size > current_size) {
360 size_t change_bytes = new_size - current_size;
361 expand(change_bytes);
362 } else {
363 size_t change_bytes = current_size - new_size;
364 // shrink doesn't grab this lock, expand does. Is that right?
365 MutexLocker x(ExpandHeap_lock);
366 shrink(change_bytes);
367 }
368
369 log_trace(gc, ergo)("AdaptiveSizePolicy::old generation size: collection: %d (" SIZE_FORMAT ") -> (" SIZE_FORMAT ") ",
370 ParallelScavengeHeap::heap()->total_collections(),
371 size_before,
372 virtual_space()->committed_size());
373 }
374
375 // NOTE! We need to be careful about resizing. During a GC, multiple
376 // allocators may be active during heap expansion. If we allow the
377 // heap resizing to become visible before we have correctly resized
378 // all heap related data structures, we may cause program failures.
379 void PSOldGen::post_resize() {
380 // First construct a memregion representing the new size
381 MemRegion new_memregion((HeapWord*)virtual_space()->low(),
382 (HeapWord*)virtual_space()->high());
383 size_t new_word_size = new_memregion.word_size();
384
385 start_array()->set_covered_region(new_memregion);
386 ParallelScavengeHeap::heap()->card_table()->resize_covered_region(new_memregion);
387
388 // ALWAYS do this last!!
389 object_space()->initialize(new_memregion,
390 SpaceDecorator::DontClear,
391 SpaceDecorator::DontMangle);
392
393 assert(new_word_size == heap_word_size(object_space()->capacity_in_bytes()),
394 "Sanity");
395 }
396
397 size_t PSOldGen::gen_size_limit() {
398 return _max_gen_size;
399 }
400
401 void PSOldGen::reset_after_change() {
402 ShouldNotReachHere();
403 return;
404 }
405
406 size_t PSOldGen::available_for_expansion() {
407 ShouldNotReachHere();
408 return 0;
409 }
410
411 size_t PSOldGen::available_for_contraction() {
412 ShouldNotReachHere();
413 return 0;
414 }
415
416 void PSOldGen::print() const { print_on(tty);}
417 void PSOldGen::print_on(outputStream* st) const {
418 st->print(" %-15s", name());
419 st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K",
420 capacity_in_bytes()/K, used_in_bytes()/K);
421 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")",
422 p2i(virtual_space()->low_boundary()),
423 p2i(virtual_space()->high()),
424 p2i(virtual_space()->high_boundary()));
425
426 st->print(" object"); object_space()->print_on(st);
427 }
428
429 void PSOldGen::print_used_change(size_t prev_used) const {
430 log_info(gc, heap)("%s: " SIZE_FORMAT "K->" SIZE_FORMAT "K(" SIZE_FORMAT "K)",
431 name(), prev_used / K, used_in_bytes() / K, capacity_in_bytes() / K);
432 }
433
434 void PSOldGen::update_counters() {
435 if (UsePerfData) {
436 _space_counters->update_all();
437 _gen_counters->update_all();
438 }
439 }
440
441 #ifndef PRODUCT
442
443 void PSOldGen::space_invariants() {
444 assert(object_space()->end() == (HeapWord*) virtual_space()->high(),
445 "Space invariant");
446 assert(object_space()->bottom() == (HeapWord*) virtual_space()->low(),
447 "Space invariant");
448 assert(virtual_space()->low_boundary() <= virtual_space()->low(),
449 "Space invariant");
450 assert(virtual_space()->high_boundary() >= virtual_space()->high(),
451 "Space invariant");
452 assert(virtual_space()->low_boundary() == (char*) _reserved.start(),
453 "Space invariant");
454 assert(virtual_space()->high_boundary() == (char*) _reserved.end(),
455 "Space invariant");
456 assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(),
457 "Space invariant");
458 }
459 #endif
460
461 void PSOldGen::verify() {
462 object_space()->verify();
463 }
464 class VerifyObjectStartArrayClosure : public ObjectClosure {
465 PSOldGen* _old_gen;
466 ObjectStartArray* _start_array;
467
468 public:
469 VerifyObjectStartArrayClosure(PSOldGen* old_gen, ObjectStartArray* start_array) :
470 _old_gen(old_gen), _start_array(start_array) { }
471
472 virtual void do_object(oop obj) {
473 HeapWord* test_addr = (HeapWord*)obj + 1;
474 guarantee(_start_array->object_start(test_addr) == (HeapWord*)obj, "ObjectStartArray cannot find start of object");
475 guarantee(_start_array->is_block_allocated((HeapWord*)obj), "ObjectStartArray missing block allocation");
476 }
477 };
478
479 void PSOldGen::verify_object_start_array() {
480 VerifyObjectStartArrayClosure check( this, &_start_array );
481 object_iterate(&check);
482 }
483
484 #ifndef PRODUCT
485 void PSOldGen::record_spaces_top() {
486 assert(ZapUnusedHeapArea, "Not mangling unused space");
487 object_space()->set_top_for_allocations();
488 }
489 #endif