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 #include "utilities/align.hpp"
38
39 inline const char* PSOldGen::select_name() {
40 return UseParallelOldGC ? "ParOldGen" : "PSOldGen";
41 }
42
43 PSOldGen::PSOldGen(ReservedSpace rs, size_t alignment,
44 size_t initial_size, size_t min_size, size_t max_size,
45 const char* perf_data_name, int level):
46 _name(select_name()), _init_gen_size(initial_size), _min_gen_size(min_size),
47 _max_gen_size(max_size)
48 {
49 initialize(rs, alignment, perf_data_name, level);
50 }
51
52 PSOldGen::PSOldGen(size_t initial_size,
53 size_t min_size, size_t max_size,
54 const char* perf_data_name, int level):
55 _name(select_name()), _init_gen_size(initial_size), _min_gen_size(min_size),
56 _max_gen_size(max_size)
57 {}
58
59 void PSOldGen::initialize(ReservedSpace rs, size_t alignment,
60 const char* perf_data_name, int level) {
61 initialize_virtual_space(rs, alignment);
62 initialize_work(perf_data_name, level);
63
64 // The old gen can grow to gen_size_limit(). _reserve reflects only
65 // the current maximum that can be committed.
66 assert(_reserved.byte_size() <= gen_size_limit(), "Consistency check");
67
68 initialize_performance_counters(perf_data_name, level);
69 }
70
71 void PSOldGen::initialize_virtual_space(ReservedSpace rs, size_t alignment) {
72
73 _virtual_space = new PSVirtualSpace(rs, alignment);
74 if (!_virtual_space->expand_by(_init_gen_size)) {
75 vm_exit_during_initialization("Could not reserve enough space for "
76 "object heap");
77 }
78 }
79
80 void PSOldGen::initialize_work(const char* perf_data_name, int level) {
81 //
82 // Basic memory initialization
83 //
84
85 MemRegion limit_reserved((HeapWord*)virtual_space()->low_boundary(),
86 heap_word_size(_max_gen_size));
87 assert(limit_reserved.byte_size() == _max_gen_size,
88 "word vs bytes confusion");
89 //
90 // Object start stuff
91 //
92
93 start_array()->initialize(limit_reserved);
94
95 _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
96 (HeapWord*)virtual_space()->high_boundary());
97
98 //
99 // Card table stuff
100 //
101
102 MemRegion cmr((HeapWord*)virtual_space()->low(),
103 (HeapWord*)virtual_space()->high());
104 if (ZapUnusedHeapArea) {
105 // Mangle newly committed space immediately rather than
106 // waiting for the initialization of the space even though
107 // mangling is related to spaces. Doing it here eliminates
108 // the need to carry along information that a complete mangling
109 // (bottom to end) needs to be done.
110 SpaceMangler::mangle_region(cmr);
111 }
112
113 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
114 BarrierSet* bs = heap->barrier_set();
115
116 bs->resize_covered_region(cmr);
117
118 CardTableModRefBS* ct = barrier_set_cast<CardTableModRefBS>(bs);
119
120 // Verify that the start and end of this generation is the start of a card.
121 // If this wasn't true, a single card could span more than one generation,
122 // which would cause problems when we commit/uncommit memory, and when we
123 // clear and dirty cards.
124 guarantee(ct->is_card_aligned(_reserved.start()), "generation must be card aligned");
125 if (_reserved.end() != heap->reserved_region().end()) {
126 // Don't check at the very end of the heap as we'll assert that we're probing off
127 // the end if we try.
128 guarantee(ct->is_card_aligned(_reserved.end()), "generation must be card aligned");
129 }
130
131 //
132 // ObjectSpace stuff
133 //
134
135 _object_space = new MutableSpace(virtual_space()->alignment());
136
137 if (_object_space == NULL)
138 vm_exit_during_initialization("Could not allocate an old gen space");
139
140 object_space()->initialize(cmr,
141 SpaceDecorator::Clear,
142 SpaceDecorator::Mangle);
143
144 _object_mark_sweep = new PSMarkSweepDecorator(_object_space, start_array(), MarkSweepDeadRatio);
145
146 if (_object_mark_sweep == NULL)
147 vm_exit_during_initialization("Could not complete allocation of old generation");
148
149 // Update the start_array
150 start_array()->set_covered_region(cmr);
151 }
152
153 void PSOldGen::initialize_performance_counters(const char* perf_data_name, int level) {
154 // Generation Counters, generation 'level', 1 subspace
155 _gen_counters = new PSGenerationCounters(perf_data_name, level, 1, _min_gen_size,
156 _max_gen_size, virtual_space());
157 _space_counters = new SpaceCounters(perf_data_name, 0,
158 virtual_space()->reserved_size(),
159 _object_space, _gen_counters);
160 }
161
162 // Assume that the generation has been allocated if its
163 // reserved size is not 0.
164 bool PSOldGen::is_allocated() {
165 return virtual_space()->reserved_size() != 0;
166 }
167
168 void PSOldGen::precompact() {
169 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
170
171 // Reset start array first.
172 start_array()->reset();
173
174 object_mark_sweep()->precompact();
175
176 // Now compact the young gen
177 heap->young_gen()->precompact();
178 }
179
180 void PSOldGen::adjust_pointers() {
181 object_mark_sweep()->adjust_pointers();
182 }
183
184 void PSOldGen::compact() {
185 object_mark_sweep()->compact(ZapUnusedHeapArea);
186 }
187
188 size_t PSOldGen::contiguous_available() const {
189 return object_space()->free_in_bytes() + virtual_space()->uncommitted_size();
190 }
191
192 // Allocation. We report all successful allocations to the size policy
193 // Note that the perm gen does not use this method, and should not!
194 HeapWord* PSOldGen::allocate(size_t word_size) {
195 assert_locked_or_safepoint(Heap_lock);
196 HeapWord* res = allocate_noexpand(word_size);
197
198 if (res == NULL) {
199 res = expand_and_allocate(word_size);
200 }
201
202 // Allocations in the old generation need to be reported
203 if (res != NULL) {
204 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
205 heap->size_policy()->tenured_allocation(word_size * HeapWordSize);
206 }
207
208 return res;
209 }
210
211 HeapWord* PSOldGen::expand_and_allocate(size_t word_size) {
212 expand(word_size*HeapWordSize);
213 if (GCExpandToAllocateDelayMillis > 0) {
214 os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false);
215 }
216 return allocate_noexpand(word_size);
217 }
218
219 HeapWord* PSOldGen::expand_and_cas_allocate(size_t word_size) {
220 expand(word_size*HeapWordSize);
221 if (GCExpandToAllocateDelayMillis > 0) {
222 os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false);
223 }
224 return cas_allocate_noexpand(word_size);
225 }
226
227 void PSOldGen::expand(size_t bytes) {
228 if (bytes == 0) {
229 return;
230 }
231 MutexLocker x(ExpandHeap_lock);
232 const size_t alignment = virtual_space()->alignment();
233 size_t aligned_bytes = align_up(bytes, alignment);
234 size_t aligned_expand_bytes = align_up(MinHeapDeltaBytes, alignment);
235
236 if (UseNUMA) {
237 // With NUMA we use round-robin page allocation for the old gen. Expand by at least
238 // providing a page per lgroup. Alignment is larger or equal to the page size.
239 aligned_expand_bytes = MAX2(aligned_expand_bytes, alignment * os::numa_get_groups_num());
240 }
241 if (aligned_bytes == 0){
242 // The alignment caused the number of bytes to wrap. An expand_by(0) will
243 // return true with the implication that and expansion was done when it
244 // was not. A call to expand implies a best effort to expand by "bytes"
245 // but not a guarantee. Align down to give a best effort. This is likely
246 // the most that the generation can expand since it has some capacity to
247 // start with.
248 aligned_bytes = align_down(bytes, alignment);
249 }
250
251 bool success = false;
252 if (aligned_expand_bytes > aligned_bytes) {
253 success = expand_by(aligned_expand_bytes);
254 }
255 if (!success) {
256 success = expand_by(aligned_bytes);
257 }
258 if (!success) {
259 success = expand_to_reserved();
260 }
261
262 if (success && GCLocker::is_active_and_needs_gc()) {
263 log_debug(gc)("Garbage collection disabled, expanded heap instead");
264 }
265 }
266
267 bool PSOldGen::expand_by(size_t bytes) {
268 assert_lock_strong(ExpandHeap_lock);
269 assert_locked_or_safepoint(Heap_lock);
270 if (bytes == 0) {
271 return true; // That's what virtual_space()->expand_by(0) would return
272 }
273 bool result = virtual_space()->expand_by(bytes);
274 if (result) {
275 if (ZapUnusedHeapArea) {
276 // We need to mangle the newly expanded area. The memregion spans
277 // end -> new_end, we assume that top -> end is already mangled.
278 // Do the mangling before post_resize() is called because
279 // the space is available for allocation after post_resize();
280 HeapWord* const virtual_space_high = (HeapWord*) virtual_space()->high();
281 assert(object_space()->end() < virtual_space_high,
282 "Should be true before post_resize()");
283 MemRegion mangle_region(object_space()->end(), virtual_space_high);
284 // Note that the object space has not yet been updated to
285 // coincide with the new underlying virtual space.
286 SpaceMangler::mangle_region(mangle_region);
287 }
288 post_resize();
289 if (UsePerfData) {
290 _space_counters->update_capacity();
291 _gen_counters->update_all();
292 }
293 }
294
295 if (result) {
296 size_t new_mem_size = virtual_space()->committed_size();
297 size_t old_mem_size = new_mem_size - bytes;
298 log_debug(gc)("Expanding %s from " SIZE_FORMAT "K by " SIZE_FORMAT "K to " SIZE_FORMAT "K",
299 name(), old_mem_size/K, bytes/K, new_mem_size/K);
300 }
301
302 return result;
303 }
304
305 bool PSOldGen::expand_to_reserved() {
306 assert_lock_strong(ExpandHeap_lock);
307 assert_locked_or_safepoint(Heap_lock);
308
309 bool result = true;
310 const size_t remaining_bytes = virtual_space()->uncommitted_size();
311 if (remaining_bytes > 0) {
312 result = expand_by(remaining_bytes);
313 DEBUG_ONLY(if (!result) log_warning(gc)("grow to reserve failed"));
314 }
315 return result;
316 }
317
318 void PSOldGen::shrink(size_t bytes) {
319 assert_lock_strong(ExpandHeap_lock);
320 assert_locked_or_safepoint(Heap_lock);
321
322 size_t size = align_down(bytes, virtual_space()->alignment());
323 if (size > 0) {
324 assert_lock_strong(ExpandHeap_lock);
325 virtual_space()->shrink_by(bytes);
326 post_resize();
327
328 size_t new_mem_size = virtual_space()->committed_size();
329 size_t old_mem_size = new_mem_size + bytes;
330 log_debug(gc)("Shrinking %s from " SIZE_FORMAT "K by " SIZE_FORMAT "K to " SIZE_FORMAT "K",
331 name(), old_mem_size/K, bytes/K, new_mem_size/K);
332 }
333 }
334
335 void PSOldGen::resize(size_t desired_free_space) {
336 const size_t alignment = virtual_space()->alignment();
337 const size_t size_before = virtual_space()->committed_size();
338 size_t new_size = used_in_bytes() + desired_free_space;
339 if (new_size < used_in_bytes()) {
340 // Overflowed the addition.
341 new_size = gen_size_limit();
342 }
343 // Adjust according to our min and max
344 new_size = MAX2(MIN2(new_size, gen_size_limit()), min_gen_size());
345
346 assert(gen_size_limit() >= reserved().byte_size(), "max new size problem?");
347 new_size = align_up(new_size, alignment);
348
349 const size_t current_size = capacity_in_bytes();
350
351 log_trace(gc, ergo)("AdaptiveSizePolicy::old generation size: "
352 "desired free: " SIZE_FORMAT " used: " SIZE_FORMAT
353 " new size: " SIZE_FORMAT " current size " SIZE_FORMAT
354 " gen limits: " SIZE_FORMAT " / " SIZE_FORMAT,
355 desired_free_space, used_in_bytes(), new_size, current_size,
356 gen_size_limit(), min_gen_size());
357
358 if (new_size == current_size) {
359 // No change requested
360 return;
361 }
362 if (new_size > current_size) {
363 size_t change_bytes = new_size - current_size;
364 expand(change_bytes);
365 } else {
366 size_t change_bytes = current_size - new_size;
367 // shrink doesn't grab this lock, expand does. Is that right?
368 MutexLocker x(ExpandHeap_lock);
369 shrink(change_bytes);
370 }
371
372 log_trace(gc, ergo)("AdaptiveSizePolicy::old generation size: collection: %d (" SIZE_FORMAT ") -> (" SIZE_FORMAT ") ",
373 ParallelScavengeHeap::heap()->total_collections(),
374 size_before,
375 virtual_space()->committed_size());
376 }
377
378 // NOTE! We need to be careful about resizing. During a GC, multiple
379 // allocators may be active during heap expansion. If we allow the
380 // heap resizing to become visible before we have correctly resized
381 // all heap related data structures, we may cause program failures.
382 void PSOldGen::post_resize() {
383 // First construct a memregion representing the new size
384 MemRegion new_memregion((HeapWord*)virtual_space()->low(),
385 (HeapWord*)virtual_space()->high());
386 size_t new_word_size = new_memregion.word_size();
387
388 start_array()->set_covered_region(new_memregion);
389 ParallelScavengeHeap::heap()->barrier_set()->resize_covered_region(new_memregion);
390
391 // ALWAYS do this last!!
392 object_space()->initialize(new_memregion,
393 SpaceDecorator::DontClear,
394 SpaceDecorator::DontMangle);
395
396 assert(new_word_size == heap_word_size(object_space()->capacity_in_bytes()),
397 "Sanity");
398 }
399
400 size_t PSOldGen::gen_size_limit() {
401 return _max_gen_size;
402 }
403
404 void PSOldGen::reset_after_change() {
405 ShouldNotReachHere();
406 return;
407 }
408
409 size_t PSOldGen::available_for_expansion() {
410 ShouldNotReachHere();
411 return 0;
412 }
413
414 size_t PSOldGen::available_for_contraction() {
415 ShouldNotReachHere();
416 return 0;
417 }
418
419 void PSOldGen::print() const { print_on(tty);}
420 void PSOldGen::print_on(outputStream* st) const {
421 st->print(" %-15s", name());
422 st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K",
423 capacity_in_bytes()/K, used_in_bytes()/K);
424 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")",
425 p2i(virtual_space()->low_boundary()),
426 p2i(virtual_space()->high()),
427 p2i(virtual_space()->high_boundary()));
428
429 st->print(" object"); object_space()->print_on(st);
430 }
431
432 void PSOldGen::print_used_change(size_t prev_used) const {
433 log_info(gc, heap)("%s: " SIZE_FORMAT "K->" SIZE_FORMAT "K(" SIZE_FORMAT "K)",
434 name(), prev_used / K, used_in_bytes() / K, capacity_in_bytes() / K);
435 }
436
437 void PSOldGen::update_counters() {
438 if (UsePerfData) {
439 _space_counters->update_all();
440 _gen_counters->update_all();
441 }
442 }
443
444 #ifndef PRODUCT
445
446 void PSOldGen::space_invariants() {
447 assert(object_space()->end() == (HeapWord*) virtual_space()->high(),
448 "Space invariant");
449 assert(object_space()->bottom() == (HeapWord*) virtual_space()->low(),
450 "Space invariant");
451 assert(virtual_space()->low_boundary() <= virtual_space()->low(),
452 "Space invariant");
453 assert(virtual_space()->high_boundary() >= virtual_space()->high(),
454 "Space invariant");
455 assert(virtual_space()->low_boundary() == (char*) _reserved.start(),
456 "Space invariant");
457 assert(virtual_space()->high_boundary() == (char*) _reserved.end(),
458 "Space invariant");
459 assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(),
460 "Space invariant");
461 }
462 #endif
463
464 void PSOldGen::verify() {
465 object_space()->verify();
466 }
467 class VerifyObjectStartArrayClosure : public ObjectClosure {
468 PSOldGen* _old_gen;
469 ObjectStartArray* _start_array;
470
471 public:
472 VerifyObjectStartArrayClosure(PSOldGen* old_gen, ObjectStartArray* start_array) :
473 _old_gen(old_gen), _start_array(start_array) { }
474
475 virtual void do_object(oop obj) {
476 HeapWord* test_addr = (HeapWord*)obj + 1;
477 guarantee(_start_array->object_start(test_addr) == (HeapWord*)obj, "ObjectStartArray cannot find start of object");
478 guarantee(_start_array->is_block_allocated((HeapWord*)obj), "ObjectStartArray missing block allocation");
479 }
480 };
481
482 void PSOldGen::verify_object_start_array() {
483 VerifyObjectStartArrayClosure check( this, &_start_array );
484 object_iterate(&check);
485 }
486
487 #ifndef PRODUCT
488 void PSOldGen::record_spaces_top() {
489 assert(ZapUnusedHeapArea, "Not mangling unused space");
490 object_space()->set_top_for_allocations();
491 }
492 #endif