Fri, 07 Sep 2012 12:04:16 -0400
7195833: NPG: Rename instanceClassLoaderKlass, instanceRefKlass and instanceMirrorKlass
Summary: Simple renaming to be consistent with instanceKlass->InstanceKlass renaming
Reviewed-by: stefank, jmasa
1 /*
2 * Copyright (c) 2005, 2012, 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 */
25 #include "precompiled.hpp"
26 #include "classfile/symbolTable.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "code/codeCache.hpp"
29 #include "gc_implementation/parallelScavenge/gcTaskManager.hpp"
30 #include "gc_implementation/parallelScavenge/generationSizer.hpp"
31 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.inline.hpp"
32 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
33 #include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp"
34 #include "gc_implementation/parallelScavenge/psCompactionManager.inline.hpp"
35 #include "gc_implementation/parallelScavenge/psMarkSweep.hpp"
36 #include "gc_implementation/parallelScavenge/psMarkSweepDecorator.hpp"
37 #include "gc_implementation/parallelScavenge/psOldGen.hpp"
38 #include "gc_implementation/parallelScavenge/psParallelCompact.hpp"
39 #include "gc_implementation/parallelScavenge/psPromotionManager.inline.hpp"
40 #include "gc_implementation/parallelScavenge/psScavenge.hpp"
41 #include "gc_implementation/parallelScavenge/psYoungGen.hpp"
42 #include "gc_implementation/shared/isGCActiveMark.hpp"
43 #include "gc_interface/gcCause.hpp"
44 #include "memory/gcLocker.inline.hpp"
45 #include "memory/referencePolicy.hpp"
46 #include "memory/referenceProcessor.hpp"
47 #include "oops/methodData.hpp"
48 #include "oops/oop.inline.hpp"
49 #include "oops/oop.pcgc.inline.hpp"
50 #include "runtime/fprofiler.hpp"
51 #include "runtime/safepoint.hpp"
52 #include "runtime/vmThread.hpp"
53 #include "services/management.hpp"
54 #include "services/memoryService.hpp"
55 #include "services/memTracker.hpp"
56 #include "utilities/events.hpp"
57 #include "utilities/stack.inline.hpp"
59 #include <math.h>
61 // All sizes are in HeapWords.
62 const size_t ParallelCompactData::Log2RegionSize = 9; // 512 words
63 const size_t ParallelCompactData::RegionSize = (size_t)1 << Log2RegionSize;
64 const size_t ParallelCompactData::RegionSizeBytes =
65 RegionSize << LogHeapWordSize;
66 const size_t ParallelCompactData::RegionSizeOffsetMask = RegionSize - 1;
67 const size_t ParallelCompactData::RegionAddrOffsetMask = RegionSizeBytes - 1;
68 const size_t ParallelCompactData::RegionAddrMask = ~RegionAddrOffsetMask;
70 const ParallelCompactData::RegionData::region_sz_t
71 ParallelCompactData::RegionData::dc_shift = 27;
73 const ParallelCompactData::RegionData::region_sz_t
74 ParallelCompactData::RegionData::dc_mask = ~0U << dc_shift;
76 const ParallelCompactData::RegionData::region_sz_t
77 ParallelCompactData::RegionData::dc_one = 0x1U << dc_shift;
79 const ParallelCompactData::RegionData::region_sz_t
80 ParallelCompactData::RegionData::los_mask = ~dc_mask;
82 const ParallelCompactData::RegionData::region_sz_t
83 ParallelCompactData::RegionData::dc_claimed = 0x8U << dc_shift;
85 const ParallelCompactData::RegionData::region_sz_t
86 ParallelCompactData::RegionData::dc_completed = 0xcU << dc_shift;
88 SpaceInfo PSParallelCompact::_space_info[PSParallelCompact::last_space_id];
89 bool PSParallelCompact::_print_phases = false;
91 ReferenceProcessor* PSParallelCompact::_ref_processor = NULL;
92 Klass* PSParallelCompact::_updated_int_array_klass_obj = NULL;
94 double PSParallelCompact::_dwl_mean;
95 double PSParallelCompact::_dwl_std_dev;
96 double PSParallelCompact::_dwl_first_term;
97 double PSParallelCompact::_dwl_adjustment;
98 #ifdef ASSERT
99 bool PSParallelCompact::_dwl_initialized = false;
100 #endif // #ifdef ASSERT
102 #ifdef VALIDATE_MARK_SWEEP
103 GrowableArray<void*>* PSParallelCompact::_root_refs_stack = NULL;
104 GrowableArray<oop> * PSParallelCompact::_live_oops = NULL;
105 GrowableArray<oop> * PSParallelCompact::_live_oops_moved_to = NULL;
106 GrowableArray<size_t>* PSParallelCompact::_live_oops_size = NULL;
107 size_t PSParallelCompact::_live_oops_index = 0;
108 GrowableArray<void*>* PSParallelCompact::_other_refs_stack = NULL;
109 GrowableArray<void*>* PSParallelCompact::_adjusted_pointers = NULL;
110 bool PSParallelCompact::_pointer_tracking = false;
111 bool PSParallelCompact::_root_tracking = true;
113 GrowableArray<HeapWord*>* PSParallelCompact::_cur_gc_live_oops = NULL;
114 GrowableArray<HeapWord*>* PSParallelCompact::_cur_gc_live_oops_moved_to = NULL;
115 GrowableArray<size_t> * PSParallelCompact::_cur_gc_live_oops_size = NULL;
116 GrowableArray<HeapWord*>* PSParallelCompact::_last_gc_live_oops = NULL;
117 GrowableArray<HeapWord*>* PSParallelCompact::_last_gc_live_oops_moved_to = NULL;
118 GrowableArray<size_t> * PSParallelCompact::_last_gc_live_oops_size = NULL;
119 #endif
121 void SplitInfo::record(size_t src_region_idx, size_t partial_obj_size,
122 HeapWord* destination)
123 {
124 assert(src_region_idx != 0, "invalid src_region_idx");
125 assert(partial_obj_size != 0, "invalid partial_obj_size argument");
126 assert(destination != NULL, "invalid destination argument");
128 _src_region_idx = src_region_idx;
129 _partial_obj_size = partial_obj_size;
130 _destination = destination;
132 // These fields may not be updated below, so make sure they're clear.
133 assert(_dest_region_addr == NULL, "should have been cleared");
134 assert(_first_src_addr == NULL, "should have been cleared");
136 // Determine the number of destination regions for the partial object.
137 HeapWord* const last_word = destination + partial_obj_size - 1;
138 const ParallelCompactData& sd = PSParallelCompact::summary_data();
139 HeapWord* const beg_region_addr = sd.region_align_down(destination);
140 HeapWord* const end_region_addr = sd.region_align_down(last_word);
142 if (beg_region_addr == end_region_addr) {
143 // One destination region.
144 _destination_count = 1;
145 if (end_region_addr == destination) {
146 // The destination falls on a region boundary, thus the first word of the
147 // partial object will be the first word copied to the destination region.
148 _dest_region_addr = end_region_addr;
149 _first_src_addr = sd.region_to_addr(src_region_idx);
150 }
151 } else {
152 // Two destination regions. When copied, the partial object will cross a
153 // destination region boundary, so a word somewhere within the partial
154 // object will be the first word copied to the second destination region.
155 _destination_count = 2;
156 _dest_region_addr = end_region_addr;
157 const size_t ofs = pointer_delta(end_region_addr, destination);
158 assert(ofs < _partial_obj_size, "sanity");
159 _first_src_addr = sd.region_to_addr(src_region_idx) + ofs;
160 }
161 }
163 void SplitInfo::clear()
164 {
165 _src_region_idx = 0;
166 _partial_obj_size = 0;
167 _destination = NULL;
168 _destination_count = 0;
169 _dest_region_addr = NULL;
170 _first_src_addr = NULL;
171 assert(!is_valid(), "sanity");
172 }
174 #ifdef ASSERT
175 void SplitInfo::verify_clear()
176 {
177 assert(_src_region_idx == 0, "not clear");
178 assert(_partial_obj_size == 0, "not clear");
179 assert(_destination == NULL, "not clear");
180 assert(_destination_count == 0, "not clear");
181 assert(_dest_region_addr == NULL, "not clear");
182 assert(_first_src_addr == NULL, "not clear");
183 }
184 #endif // #ifdef ASSERT
187 #ifndef PRODUCT
188 const char* PSParallelCompact::space_names[] = {
189 "old ", "eden", "from", "to "
190 };
192 void PSParallelCompact::print_region_ranges()
193 {
194 tty->print_cr("space bottom top end new_top");
195 tty->print_cr("------ ---------- ---------- ---------- ----------");
197 for (unsigned int id = 0; id < last_space_id; ++id) {
198 const MutableSpace* space = _space_info[id].space();
199 tty->print_cr("%u %s "
200 SIZE_FORMAT_W(10) " " SIZE_FORMAT_W(10) " "
201 SIZE_FORMAT_W(10) " " SIZE_FORMAT_W(10) " ",
202 id, space_names[id],
203 summary_data().addr_to_region_idx(space->bottom()),
204 summary_data().addr_to_region_idx(space->top()),
205 summary_data().addr_to_region_idx(space->end()),
206 summary_data().addr_to_region_idx(_space_info[id].new_top()));
207 }
208 }
210 void
211 print_generic_summary_region(size_t i, const ParallelCompactData::RegionData* c)
212 {
213 #define REGION_IDX_FORMAT SIZE_FORMAT_W(7)
214 #define REGION_DATA_FORMAT SIZE_FORMAT_W(5)
216 ParallelCompactData& sd = PSParallelCompact::summary_data();
217 size_t dci = c->destination() ? sd.addr_to_region_idx(c->destination()) : 0;
218 tty->print_cr(REGION_IDX_FORMAT " " PTR_FORMAT " "
219 REGION_IDX_FORMAT " " PTR_FORMAT " "
220 REGION_DATA_FORMAT " " REGION_DATA_FORMAT " "
221 REGION_DATA_FORMAT " " REGION_IDX_FORMAT " %d",
222 i, c->data_location(), dci, c->destination(),
223 c->partial_obj_size(), c->live_obj_size(),
224 c->data_size(), c->source_region(), c->destination_count());
226 #undef REGION_IDX_FORMAT
227 #undef REGION_DATA_FORMAT
228 }
230 void
231 print_generic_summary_data(ParallelCompactData& summary_data,
232 HeapWord* const beg_addr,
233 HeapWord* const end_addr)
234 {
235 size_t total_words = 0;
236 size_t i = summary_data.addr_to_region_idx(beg_addr);
237 const size_t last = summary_data.addr_to_region_idx(end_addr);
238 HeapWord* pdest = 0;
240 while (i <= last) {
241 ParallelCompactData::RegionData* c = summary_data.region(i);
242 if (c->data_size() != 0 || c->destination() != pdest) {
243 print_generic_summary_region(i, c);
244 total_words += c->data_size();
245 pdest = c->destination();
246 }
247 ++i;
248 }
250 tty->print_cr("summary_data_bytes=" SIZE_FORMAT, total_words * HeapWordSize);
251 }
253 void
254 print_generic_summary_data(ParallelCompactData& summary_data,
255 SpaceInfo* space_info)
256 {
257 for (unsigned int id = 0; id < PSParallelCompact::last_space_id; ++id) {
258 const MutableSpace* space = space_info[id].space();
259 print_generic_summary_data(summary_data, space->bottom(),
260 MAX2(space->top(), space_info[id].new_top()));
261 }
262 }
264 void
265 print_initial_summary_region(size_t i,
266 const ParallelCompactData::RegionData* c,
267 bool newline = true)
268 {
269 tty->print(SIZE_FORMAT_W(5) " " PTR_FORMAT " "
270 SIZE_FORMAT_W(5) " " SIZE_FORMAT_W(5) " "
271 SIZE_FORMAT_W(5) " " SIZE_FORMAT_W(5) " %d",
272 i, c->destination(),
273 c->partial_obj_size(), c->live_obj_size(),
274 c->data_size(), c->source_region(), c->destination_count());
275 if (newline) tty->cr();
276 }
278 void
279 print_initial_summary_data(ParallelCompactData& summary_data,
280 const MutableSpace* space) {
281 if (space->top() == space->bottom()) {
282 return;
283 }
285 const size_t region_size = ParallelCompactData::RegionSize;
286 typedef ParallelCompactData::RegionData RegionData;
287 HeapWord* const top_aligned_up = summary_data.region_align_up(space->top());
288 const size_t end_region = summary_data.addr_to_region_idx(top_aligned_up);
289 const RegionData* c = summary_data.region(end_region - 1);
290 HeapWord* end_addr = c->destination() + c->data_size();
291 const size_t live_in_space = pointer_delta(end_addr, space->bottom());
293 // Print (and count) the full regions at the beginning of the space.
294 size_t full_region_count = 0;
295 size_t i = summary_data.addr_to_region_idx(space->bottom());
296 while (i < end_region && summary_data.region(i)->data_size() == region_size) {
297 print_initial_summary_region(i, summary_data.region(i));
298 ++full_region_count;
299 ++i;
300 }
302 size_t live_to_right = live_in_space - full_region_count * region_size;
304 double max_reclaimed_ratio = 0.0;
305 size_t max_reclaimed_ratio_region = 0;
306 size_t max_dead_to_right = 0;
307 size_t max_live_to_right = 0;
309 // Print the 'reclaimed ratio' for regions while there is something live in
310 // the region or to the right of it. The remaining regions are empty (and
311 // uninteresting), and computing the ratio will result in division by 0.
312 while (i < end_region && live_to_right > 0) {
313 c = summary_data.region(i);
314 HeapWord* const region_addr = summary_data.region_to_addr(i);
315 const size_t used_to_right = pointer_delta(space->top(), region_addr);
316 const size_t dead_to_right = used_to_right - live_to_right;
317 const double reclaimed_ratio = double(dead_to_right) / live_to_right;
319 if (reclaimed_ratio > max_reclaimed_ratio) {
320 max_reclaimed_ratio = reclaimed_ratio;
321 max_reclaimed_ratio_region = i;
322 max_dead_to_right = dead_to_right;
323 max_live_to_right = live_to_right;
324 }
326 print_initial_summary_region(i, c, false);
327 tty->print_cr(" %12.10f " SIZE_FORMAT_W(10) " " SIZE_FORMAT_W(10),
328 reclaimed_ratio, dead_to_right, live_to_right);
330 live_to_right -= c->data_size();
331 ++i;
332 }
334 // Any remaining regions are empty. Print one more if there is one.
335 if (i < end_region) {
336 print_initial_summary_region(i, summary_data.region(i));
337 }
339 tty->print_cr("max: " SIZE_FORMAT_W(4) " d2r=" SIZE_FORMAT_W(10) " "
340 "l2r=" SIZE_FORMAT_W(10) " max_ratio=%14.12f",
341 max_reclaimed_ratio_region, max_dead_to_right,
342 max_live_to_right, max_reclaimed_ratio);
343 }
345 void
346 print_initial_summary_data(ParallelCompactData& summary_data,
347 SpaceInfo* space_info) {
348 unsigned int id = PSParallelCompact::old_space_id;
349 const MutableSpace* space;
350 do {
351 space = space_info[id].space();
352 print_initial_summary_data(summary_data, space);
353 } while (++id < PSParallelCompact::eden_space_id);
355 do {
356 space = space_info[id].space();
357 print_generic_summary_data(summary_data, space->bottom(), space->top());
358 } while (++id < PSParallelCompact::last_space_id);
359 }
360 #endif // #ifndef PRODUCT
362 #ifdef ASSERT
363 size_t add_obj_count;
364 size_t add_obj_size;
365 size_t mark_bitmap_count;
366 size_t mark_bitmap_size;
367 #endif // #ifdef ASSERT
369 ParallelCompactData::ParallelCompactData()
370 {
371 _region_start = 0;
373 _region_vspace = 0;
374 _region_data = 0;
375 _region_count = 0;
376 }
378 bool ParallelCompactData::initialize(MemRegion covered_region)
379 {
380 _region_start = covered_region.start();
381 const size_t region_size = covered_region.word_size();
382 DEBUG_ONLY(_region_end = _region_start + region_size;)
384 assert(region_align_down(_region_start) == _region_start,
385 "region start not aligned");
386 assert((region_size & RegionSizeOffsetMask) == 0,
387 "region size not a multiple of RegionSize");
389 bool result = initialize_region_data(region_size);
391 return result;
392 }
394 PSVirtualSpace*
395 ParallelCompactData::create_vspace(size_t count, size_t element_size)
396 {
397 const size_t raw_bytes = count * element_size;
398 const size_t page_sz = os::page_size_for_region(raw_bytes, raw_bytes, 10);
399 const size_t granularity = os::vm_allocation_granularity();
400 const size_t bytes = align_size_up(raw_bytes, MAX2(page_sz, granularity));
402 const size_t rs_align = page_sz == (size_t) os::vm_page_size() ? 0 :
403 MAX2(page_sz, granularity);
404 ReservedSpace rs(bytes, rs_align, rs_align > 0);
405 os::trace_page_sizes("par compact", raw_bytes, raw_bytes, page_sz, rs.base(),
406 rs.size());
408 MemTracker::record_virtual_memory_type((address)rs.base(), mtGC);
410 PSVirtualSpace* vspace = new PSVirtualSpace(rs, page_sz);
411 if (vspace != 0) {
412 if (vspace->expand_by(bytes)) {
413 return vspace;
414 }
415 delete vspace;
416 // Release memory reserved in the space.
417 rs.release();
418 }
420 return 0;
421 }
423 bool ParallelCompactData::initialize_region_data(size_t region_size)
424 {
425 const size_t count = (region_size + RegionSizeOffsetMask) >> Log2RegionSize;
426 _region_vspace = create_vspace(count, sizeof(RegionData));
427 if (_region_vspace != 0) {
428 _region_data = (RegionData*)_region_vspace->reserved_low_addr();
429 _region_count = count;
430 return true;
431 }
432 return false;
433 }
435 void ParallelCompactData::clear()
436 {
437 memset(_region_data, 0, _region_vspace->committed_size());
438 }
440 void ParallelCompactData::clear_range(size_t beg_region, size_t end_region) {
441 assert(beg_region <= _region_count, "beg_region out of range");
442 assert(end_region <= _region_count, "end_region out of range");
444 const size_t region_cnt = end_region - beg_region;
445 memset(_region_data + beg_region, 0, region_cnt * sizeof(RegionData));
446 }
448 HeapWord* ParallelCompactData::partial_obj_end(size_t region_idx) const
449 {
450 const RegionData* cur_cp = region(region_idx);
451 const RegionData* const end_cp = region(region_count() - 1);
453 HeapWord* result = region_to_addr(region_idx);
454 if (cur_cp < end_cp) {
455 do {
456 result += cur_cp->partial_obj_size();
457 } while (cur_cp->partial_obj_size() == RegionSize && ++cur_cp < end_cp);
458 }
459 return result;
460 }
462 void ParallelCompactData::add_obj(HeapWord* addr, size_t len)
463 {
464 const size_t obj_ofs = pointer_delta(addr, _region_start);
465 const size_t beg_region = obj_ofs >> Log2RegionSize;
466 const size_t end_region = (obj_ofs + len - 1) >> Log2RegionSize;
468 DEBUG_ONLY(Atomic::inc_ptr(&add_obj_count);)
469 DEBUG_ONLY(Atomic::add_ptr(len, &add_obj_size);)
471 if (beg_region == end_region) {
472 // All in one region.
473 _region_data[beg_region].add_live_obj(len);
474 return;
475 }
477 // First region.
478 const size_t beg_ofs = region_offset(addr);
479 _region_data[beg_region].add_live_obj(RegionSize - beg_ofs);
481 Klass* klass = ((oop)addr)->klass();
482 // Middle regions--completely spanned by this object.
483 for (size_t region = beg_region + 1; region < end_region; ++region) {
484 _region_data[region].set_partial_obj_size(RegionSize);
485 _region_data[region].set_partial_obj_addr(addr);
486 }
488 // Last region.
489 const size_t end_ofs = region_offset(addr + len - 1);
490 _region_data[end_region].set_partial_obj_size(end_ofs + 1);
491 _region_data[end_region].set_partial_obj_addr(addr);
492 }
494 void
495 ParallelCompactData::summarize_dense_prefix(HeapWord* beg, HeapWord* end)
496 {
497 assert(region_offset(beg) == 0, "not RegionSize aligned");
498 assert(region_offset(end) == 0, "not RegionSize aligned");
500 size_t cur_region = addr_to_region_idx(beg);
501 const size_t end_region = addr_to_region_idx(end);
502 HeapWord* addr = beg;
503 while (cur_region < end_region) {
504 _region_data[cur_region].set_destination(addr);
505 _region_data[cur_region].set_destination_count(0);
506 _region_data[cur_region].set_source_region(cur_region);
507 _region_data[cur_region].set_data_location(addr);
509 // Update live_obj_size so the region appears completely full.
510 size_t live_size = RegionSize - _region_data[cur_region].partial_obj_size();
511 _region_data[cur_region].set_live_obj_size(live_size);
513 ++cur_region;
514 addr += RegionSize;
515 }
516 }
518 // Find the point at which a space can be split and, if necessary, record the
519 // split point.
520 //
521 // If the current src region (which overflowed the destination space) doesn't
522 // have a partial object, the split point is at the beginning of the current src
523 // region (an "easy" split, no extra bookkeeping required).
524 //
525 // If the current src region has a partial object, the split point is in the
526 // region where that partial object starts (call it the split_region). If
527 // split_region has a partial object, then the split point is just after that
528 // partial object (a "hard" split where we have to record the split data and
529 // zero the partial_obj_size field). With a "hard" split, we know that the
530 // partial_obj ends within split_region because the partial object that caused
531 // the overflow starts in split_region. If split_region doesn't have a partial
532 // obj, then the split is at the beginning of split_region (another "easy"
533 // split).
534 HeapWord*
535 ParallelCompactData::summarize_split_space(size_t src_region,
536 SplitInfo& split_info,
537 HeapWord* destination,
538 HeapWord* target_end,
539 HeapWord** target_next)
540 {
541 assert(destination <= target_end, "sanity");
542 assert(destination + _region_data[src_region].data_size() > target_end,
543 "region should not fit into target space");
544 assert(is_region_aligned(target_end), "sanity");
546 size_t split_region = src_region;
547 HeapWord* split_destination = destination;
548 size_t partial_obj_size = _region_data[src_region].partial_obj_size();
550 if (destination + partial_obj_size > target_end) {
551 // The split point is just after the partial object (if any) in the
552 // src_region that contains the start of the object that overflowed the
553 // destination space.
554 //
555 // Find the start of the "overflow" object and set split_region to the
556 // region containing it.
557 HeapWord* const overflow_obj = _region_data[src_region].partial_obj_addr();
558 split_region = addr_to_region_idx(overflow_obj);
560 // Clear the source_region field of all destination regions whose first word
561 // came from data after the split point (a non-null source_region field
562 // implies a region must be filled).
563 //
564 // An alternative to the simple loop below: clear during post_compact(),
565 // which uses memcpy instead of individual stores, and is easy to
566 // parallelize. (The downside is that it clears the entire RegionData
567 // object as opposed to just one field.)
568 //
569 // post_compact() would have to clear the summary data up to the highest
570 // address that was written during the summary phase, which would be
571 //
572 // max(top, max(new_top, clear_top))
573 //
574 // where clear_top is a new field in SpaceInfo. Would have to set clear_top
575 // to target_end.
576 const RegionData* const sr = region(split_region);
577 const size_t beg_idx =
578 addr_to_region_idx(region_align_up(sr->destination() +
579 sr->partial_obj_size()));
580 const size_t end_idx = addr_to_region_idx(target_end);
582 if (TraceParallelOldGCSummaryPhase) {
583 gclog_or_tty->print_cr("split: clearing source_region field in ["
584 SIZE_FORMAT ", " SIZE_FORMAT ")",
585 beg_idx, end_idx);
586 }
587 for (size_t idx = beg_idx; idx < end_idx; ++idx) {
588 _region_data[idx].set_source_region(0);
589 }
591 // Set split_destination and partial_obj_size to reflect the split region.
592 split_destination = sr->destination();
593 partial_obj_size = sr->partial_obj_size();
594 }
596 // The split is recorded only if a partial object extends onto the region.
597 if (partial_obj_size != 0) {
598 _region_data[split_region].set_partial_obj_size(0);
599 split_info.record(split_region, partial_obj_size, split_destination);
600 }
602 // Setup the continuation addresses.
603 *target_next = split_destination + partial_obj_size;
604 HeapWord* const source_next = region_to_addr(split_region) + partial_obj_size;
606 if (TraceParallelOldGCSummaryPhase) {
607 const char * split_type = partial_obj_size == 0 ? "easy" : "hard";
608 gclog_or_tty->print_cr("%s split: src=" PTR_FORMAT " src_c=" SIZE_FORMAT
609 " pos=" SIZE_FORMAT,
610 split_type, source_next, split_region,
611 partial_obj_size);
612 gclog_or_tty->print_cr("%s split: dst=" PTR_FORMAT " dst_c=" SIZE_FORMAT
613 " tn=" PTR_FORMAT,
614 split_type, split_destination,
615 addr_to_region_idx(split_destination),
616 *target_next);
618 if (partial_obj_size != 0) {
619 HeapWord* const po_beg = split_info.destination();
620 HeapWord* const po_end = po_beg + split_info.partial_obj_size();
621 gclog_or_tty->print_cr("%s split: "
622 "po_beg=" PTR_FORMAT " " SIZE_FORMAT " "
623 "po_end=" PTR_FORMAT " " SIZE_FORMAT,
624 split_type,
625 po_beg, addr_to_region_idx(po_beg),
626 po_end, addr_to_region_idx(po_end));
627 }
628 }
630 return source_next;
631 }
633 bool ParallelCompactData::summarize(SplitInfo& split_info,
634 HeapWord* source_beg, HeapWord* source_end,
635 HeapWord** source_next,
636 HeapWord* target_beg, HeapWord* target_end,
637 HeapWord** target_next)
638 {
639 if (TraceParallelOldGCSummaryPhase) {
640 HeapWord* const source_next_val = source_next == NULL ? NULL : *source_next;
641 tty->print_cr("sb=" PTR_FORMAT " se=" PTR_FORMAT " sn=" PTR_FORMAT
642 "tb=" PTR_FORMAT " te=" PTR_FORMAT " tn=" PTR_FORMAT,
643 source_beg, source_end, source_next_val,
644 target_beg, target_end, *target_next);
645 }
647 size_t cur_region = addr_to_region_idx(source_beg);
648 const size_t end_region = addr_to_region_idx(region_align_up(source_end));
650 HeapWord *dest_addr = target_beg;
651 while (cur_region < end_region) {
652 // The destination must be set even if the region has no data.
653 _region_data[cur_region].set_destination(dest_addr);
655 size_t words = _region_data[cur_region].data_size();
656 if (words > 0) {
657 // If cur_region does not fit entirely into the target space, find a point
658 // at which the source space can be 'split' so that part is copied to the
659 // target space and the rest is copied elsewhere.
660 if (dest_addr + words > target_end) {
661 assert(source_next != NULL, "source_next is NULL when splitting");
662 *source_next = summarize_split_space(cur_region, split_info, dest_addr,
663 target_end, target_next);
664 return false;
665 }
667 // Compute the destination_count for cur_region, and if necessary, update
668 // source_region for a destination region. The source_region field is
669 // updated if cur_region is the first (left-most) region to be copied to a
670 // destination region.
671 //
672 // The destination_count calculation is a bit subtle. A region that has
673 // data that compacts into itself does not count itself as a destination.
674 // This maintains the invariant that a zero count means the region is
675 // available and can be claimed and then filled.
676 uint destination_count = 0;
677 if (split_info.is_split(cur_region)) {
678 // The current region has been split: the partial object will be copied
679 // to one destination space and the remaining data will be copied to
680 // another destination space. Adjust the initial destination_count and,
681 // if necessary, set the source_region field if the partial object will
682 // cross a destination region boundary.
683 destination_count = split_info.destination_count();
684 if (destination_count == 2) {
685 size_t dest_idx = addr_to_region_idx(split_info.dest_region_addr());
686 _region_data[dest_idx].set_source_region(cur_region);
687 }
688 }
690 HeapWord* const last_addr = dest_addr + words - 1;
691 const size_t dest_region_1 = addr_to_region_idx(dest_addr);
692 const size_t dest_region_2 = addr_to_region_idx(last_addr);
694 // Initially assume that the destination regions will be the same and
695 // adjust the value below if necessary. Under this assumption, if
696 // cur_region == dest_region_2, then cur_region will be compacted
697 // completely into itself.
698 destination_count += cur_region == dest_region_2 ? 0 : 1;
699 if (dest_region_1 != dest_region_2) {
700 // Destination regions differ; adjust destination_count.
701 destination_count += 1;
702 // Data from cur_region will be copied to the start of dest_region_2.
703 _region_data[dest_region_2].set_source_region(cur_region);
704 } else if (region_offset(dest_addr) == 0) {
705 // Data from cur_region will be copied to the start of the destination
706 // region.
707 _region_data[dest_region_1].set_source_region(cur_region);
708 }
710 _region_data[cur_region].set_destination_count(destination_count);
711 _region_data[cur_region].set_data_location(region_to_addr(cur_region));
712 dest_addr += words;
713 }
715 ++cur_region;
716 }
718 *target_next = dest_addr;
719 return true;
720 }
722 HeapWord* ParallelCompactData::calc_new_pointer(HeapWord* addr) {
723 assert(addr != NULL, "Should detect NULL oop earlier");
724 assert(PSParallelCompact::gc_heap()->is_in(addr), "addr not in heap");
725 #ifdef ASSERT
726 if (PSParallelCompact::mark_bitmap()->is_unmarked(addr)) {
727 gclog_or_tty->print_cr("calc_new_pointer:: addr " PTR_FORMAT, addr);
728 }
729 #endif
730 assert(PSParallelCompact::mark_bitmap()->is_marked(addr), "obj not marked");
732 // Region covering the object.
733 size_t region_index = addr_to_region_idx(addr);
734 const RegionData* const region_ptr = region(region_index);
735 HeapWord* const region_addr = region_align_down(addr);
737 assert(addr < region_addr + RegionSize, "Region does not cover object");
738 assert(addr_to_region_ptr(region_addr) == region_ptr, "sanity check");
740 HeapWord* result = region_ptr->destination();
742 // If all the data in the region is live, then the new location of the object
743 // can be calculated from the destination of the region plus the offset of the
744 // object in the region.
745 if (region_ptr->data_size() == RegionSize) {
746 result += pointer_delta(addr, region_addr);
747 DEBUG_ONLY(PSParallelCompact::check_new_location(addr, result);)
748 return result;
749 }
751 // The new location of the object is
752 // region destination +
753 // size of the partial object extending onto the region +
754 // sizes of the live objects in the Region that are to the left of addr
755 const size_t partial_obj_size = region_ptr->partial_obj_size();
756 HeapWord* const search_start = region_addr + partial_obj_size;
758 const ParMarkBitMap* bitmap = PSParallelCompact::mark_bitmap();
759 size_t live_to_left = bitmap->live_words_in_range(search_start, oop(addr));
761 result += partial_obj_size + live_to_left;
762 DEBUG_ONLY(PSParallelCompact::check_new_location(addr, result);)
763 return result;
764 }
766 #ifdef ASSERT
767 void ParallelCompactData::verify_clear(const PSVirtualSpace* vspace)
768 {
769 const size_t* const beg = (const size_t*)vspace->committed_low_addr();
770 const size_t* const end = (const size_t*)vspace->committed_high_addr();
771 for (const size_t* p = beg; p < end; ++p) {
772 assert(*p == 0, "not zero");
773 }
774 }
776 void ParallelCompactData::verify_clear()
777 {
778 verify_clear(_region_vspace);
779 }
780 #endif // #ifdef ASSERT
782 #ifdef NOT_PRODUCT
783 ParallelCompactData::RegionData* debug_region(size_t region_index) {
784 ParallelCompactData& sd = PSParallelCompact::summary_data();
785 return sd.region(region_index);
786 }
787 #endif
789 elapsedTimer PSParallelCompact::_accumulated_time;
790 unsigned int PSParallelCompact::_total_invocations = 0;
791 unsigned int PSParallelCompact::_maximum_compaction_gc_num = 0;
792 jlong PSParallelCompact::_time_of_last_gc = 0;
793 CollectorCounters* PSParallelCompact::_counters = NULL;
794 ParMarkBitMap PSParallelCompact::_mark_bitmap;
795 ParallelCompactData PSParallelCompact::_summary_data;
797 PSParallelCompact::IsAliveClosure PSParallelCompact::_is_alive_closure;
799 void PSParallelCompact::IsAliveClosure::do_object(oop p) { ShouldNotReachHere(); }
800 bool PSParallelCompact::IsAliveClosure::do_object_b(oop p) { return mark_bitmap()->is_marked(p); }
802 void PSParallelCompact::KeepAliveClosure::do_oop(oop* p) { PSParallelCompact::KeepAliveClosure::do_oop_work(p); }
803 void PSParallelCompact::KeepAliveClosure::do_oop(narrowOop* p) { PSParallelCompact::KeepAliveClosure::do_oop_work(p); }
805 PSParallelCompact::AdjustPointerClosure PSParallelCompact::_adjust_root_pointer_closure(true);
806 PSParallelCompact::AdjustPointerClosure PSParallelCompact::_adjust_pointer_closure(false);
807 PSParallelCompact::AdjustKlassClosure PSParallelCompact::_adjust_klass_closure;
809 void PSParallelCompact::AdjustPointerClosure::do_oop(oop* p) { adjust_pointer(p, _is_root); }
810 void PSParallelCompact::AdjustPointerClosure::do_oop(narrowOop* p) { adjust_pointer(p, _is_root); }
812 void PSParallelCompact::FollowStackClosure::do_void() { _compaction_manager->follow_marking_stacks(); }
814 void PSParallelCompact::MarkAndPushClosure::do_oop(oop* p) {
815 mark_and_push(_compaction_manager, p);
816 }
817 void PSParallelCompact::MarkAndPushClosure::do_oop(narrowOop* p) { mark_and_push(_compaction_manager, p); }
819 void PSParallelCompact::FollowKlassClosure::do_klass(Klass* klass) {
820 klass->oops_do(_mark_and_push_closure);
821 }
822 void PSParallelCompact::AdjustKlassClosure::do_klass(Klass* klass) {
823 klass->oops_do(&PSParallelCompact::_adjust_root_pointer_closure);
824 }
826 void PSParallelCompact::post_initialize() {
827 ParallelScavengeHeap* heap = gc_heap();
828 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
830 MemRegion mr = heap->reserved_region();
831 _ref_processor =
832 new ReferenceProcessor(mr, // span
833 ParallelRefProcEnabled && (ParallelGCThreads > 1), // mt processing
834 (int) ParallelGCThreads, // mt processing degree
835 true, // mt discovery
836 (int) ParallelGCThreads, // mt discovery degree
837 true, // atomic_discovery
838 &_is_alive_closure, // non-header is alive closure
839 false); // write barrier for next field updates
840 _counters = new CollectorCounters("PSParallelCompact", 1);
842 // Initialize static fields in ParCompactionManager.
843 ParCompactionManager::initialize(mark_bitmap());
844 }
846 bool PSParallelCompact::initialize() {
847 ParallelScavengeHeap* heap = gc_heap();
848 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
849 MemRegion mr = heap->reserved_region();
851 // Was the old gen get allocated successfully?
852 if (!heap->old_gen()->is_allocated()) {
853 return false;
854 }
856 initialize_space_info();
857 initialize_dead_wood_limiter();
859 if (!_mark_bitmap.initialize(mr)) {
860 vm_shutdown_during_initialization("Unable to allocate bit map for "
861 "parallel garbage collection for the requested heap size.");
862 return false;
863 }
865 if (!_summary_data.initialize(mr)) {
866 vm_shutdown_during_initialization("Unable to allocate tables for "
867 "parallel garbage collection for the requested heap size.");
868 return false;
869 }
871 return true;
872 }
874 void PSParallelCompact::initialize_space_info()
875 {
876 memset(&_space_info, 0, sizeof(_space_info));
878 ParallelScavengeHeap* heap = gc_heap();
879 PSYoungGen* young_gen = heap->young_gen();
881 _space_info[old_space_id].set_space(heap->old_gen()->object_space());
882 _space_info[eden_space_id].set_space(young_gen->eden_space());
883 _space_info[from_space_id].set_space(young_gen->from_space());
884 _space_info[to_space_id].set_space(young_gen->to_space());
886 _space_info[old_space_id].set_start_array(heap->old_gen()->start_array());
887 }
889 void PSParallelCompact::initialize_dead_wood_limiter()
890 {
891 const size_t max = 100;
892 _dwl_mean = double(MIN2(ParallelOldDeadWoodLimiterMean, max)) / 100.0;
893 _dwl_std_dev = double(MIN2(ParallelOldDeadWoodLimiterStdDev, max)) / 100.0;
894 _dwl_first_term = 1.0 / (sqrt(2.0 * M_PI) * _dwl_std_dev);
895 DEBUG_ONLY(_dwl_initialized = true;)
896 _dwl_adjustment = normal_distribution(1.0);
897 }
899 // Simple class for storing info about the heap at the start of GC, to be used
900 // after GC for comparison/printing.
901 class PreGCValues {
902 public:
903 PreGCValues() { }
904 PreGCValues(ParallelScavengeHeap* heap) { fill(heap); }
906 void fill(ParallelScavengeHeap* heap) {
907 _heap_used = heap->used();
908 _young_gen_used = heap->young_gen()->used_in_bytes();
909 _old_gen_used = heap->old_gen()->used_in_bytes();
910 _metadata_used = MetaspaceAux::used_in_bytes();
911 };
913 size_t heap_used() const { return _heap_used; }
914 size_t young_gen_used() const { return _young_gen_used; }
915 size_t old_gen_used() const { return _old_gen_used; }
916 size_t metadata_used() const { return _metadata_used; }
918 private:
919 size_t _heap_used;
920 size_t _young_gen_used;
921 size_t _old_gen_used;
922 size_t _metadata_used;
923 };
925 void
926 PSParallelCompact::clear_data_covering_space(SpaceId id)
927 {
928 // At this point, top is the value before GC, new_top() is the value that will
929 // be set at the end of GC. The marking bitmap is cleared to top; nothing
930 // should be marked above top. The summary data is cleared to the larger of
931 // top & new_top.
932 MutableSpace* const space = _space_info[id].space();
933 HeapWord* const bot = space->bottom();
934 HeapWord* const top = space->top();
935 HeapWord* const max_top = MAX2(top, _space_info[id].new_top());
937 const idx_t beg_bit = _mark_bitmap.addr_to_bit(bot);
938 const idx_t end_bit = BitMap::word_align_up(_mark_bitmap.addr_to_bit(top));
939 _mark_bitmap.clear_range(beg_bit, end_bit);
941 const size_t beg_region = _summary_data.addr_to_region_idx(bot);
942 const size_t end_region =
943 _summary_data.addr_to_region_idx(_summary_data.region_align_up(max_top));
944 _summary_data.clear_range(beg_region, end_region);
946 // Clear the data used to 'split' regions.
947 SplitInfo& split_info = _space_info[id].split_info();
948 if (split_info.is_valid()) {
949 split_info.clear();
950 }
951 DEBUG_ONLY(split_info.verify_clear();)
952 }
954 void PSParallelCompact::pre_compact(PreGCValues* pre_gc_values)
955 {
956 // Update the from & to space pointers in space_info, since they are swapped
957 // at each young gen gc. Do the update unconditionally (even though a
958 // promotion failure does not swap spaces) because an unknown number of minor
959 // collections will have swapped the spaces an unknown number of times.
960 TraceTime tm("pre compact", print_phases(), true, gclog_or_tty);
961 ParallelScavengeHeap* heap = gc_heap();
962 _space_info[from_space_id].set_space(heap->young_gen()->from_space());
963 _space_info[to_space_id].set_space(heap->young_gen()->to_space());
965 pre_gc_values->fill(heap);
967 NOT_PRODUCT(_mark_bitmap.reset_counters());
968 DEBUG_ONLY(add_obj_count = add_obj_size = 0;)
969 DEBUG_ONLY(mark_bitmap_count = mark_bitmap_size = 0;)
971 // Increment the invocation count
972 heap->increment_total_collections(true);
974 // We need to track unique mark sweep invocations as well.
975 _total_invocations++;
977 heap->print_heap_before_gc();
979 // Fill in TLABs
980 heap->accumulate_statistics_all_tlabs();
981 heap->ensure_parsability(true); // retire TLABs
983 if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) {
984 HandleMark hm; // Discard invalid handles created during verification
985 gclog_or_tty->print(" VerifyBeforeGC:");
986 Universe::verify(true);
987 }
989 // Verify object start arrays
990 if (VerifyObjectStartArray &&
991 VerifyBeforeGC) {
992 heap->old_gen()->verify_object_start_array();
993 }
995 DEBUG_ONLY(mark_bitmap()->verify_clear();)
996 DEBUG_ONLY(summary_data().verify_clear();)
998 // Have worker threads release resources the next time they run a task.
999 gc_task_manager()->release_all_resources();
1000 }
1002 void PSParallelCompact::post_compact()
1003 {
1004 TraceTime tm("post compact", print_phases(), true, gclog_or_tty);
1006 for (unsigned int id = old_space_id; id < last_space_id; ++id) {
1007 // Clear the marking bitmap, summary data and split info.
1008 clear_data_covering_space(SpaceId(id));
1009 // Update top(). Must be done after clearing the bitmap and summary data.
1010 _space_info[id].publish_new_top();
1011 }
1013 MutableSpace* const eden_space = _space_info[eden_space_id].space();
1014 MutableSpace* const from_space = _space_info[from_space_id].space();
1015 MutableSpace* const to_space = _space_info[to_space_id].space();
1017 ParallelScavengeHeap* heap = gc_heap();
1018 bool eden_empty = eden_space->is_empty();
1019 if (!eden_empty) {
1020 eden_empty = absorb_live_data_from_eden(heap->size_policy(),
1021 heap->young_gen(), heap->old_gen());
1022 }
1024 // Update heap occupancy information which is used as input to the soft ref
1025 // clearing policy at the next gc.
1026 Universe::update_heap_info_at_gc();
1028 bool young_gen_empty = eden_empty && from_space->is_empty() &&
1029 to_space->is_empty();
1031 BarrierSet* bs = heap->barrier_set();
1032 if (bs->is_a(BarrierSet::ModRef)) {
1033 ModRefBarrierSet* modBS = (ModRefBarrierSet*)bs;
1034 MemRegion old_mr = heap->old_gen()->reserved();
1036 if (young_gen_empty) {
1037 modBS->clear(MemRegion(old_mr.start(), old_mr.end()));
1038 } else {
1039 modBS->invalidate(MemRegion(old_mr.start(), old_mr.end()));
1040 }
1041 }
1043 // Delete metaspaces for unloaded class loaders and clean up loader_data graph
1044 ClassLoaderDataGraph::purge();
1046 Threads::gc_epilogue();
1047 CodeCache::gc_epilogue();
1048 JvmtiExport::gc_epilogue();
1050 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
1052 ref_processor()->enqueue_discovered_references(NULL);
1054 if (ZapUnusedHeapArea) {
1055 heap->gen_mangle_unused_area();
1056 }
1058 // Update time of last GC
1059 reset_millis_since_last_gc();
1060 }
1062 HeapWord*
1063 PSParallelCompact::compute_dense_prefix_via_density(const SpaceId id,
1064 bool maximum_compaction)
1065 {
1066 const size_t region_size = ParallelCompactData::RegionSize;
1067 const ParallelCompactData& sd = summary_data();
1069 const MutableSpace* const space = _space_info[id].space();
1070 HeapWord* const top_aligned_up = sd.region_align_up(space->top());
1071 const RegionData* const beg_cp = sd.addr_to_region_ptr(space->bottom());
1072 const RegionData* const end_cp = sd.addr_to_region_ptr(top_aligned_up);
1074 // Skip full regions at the beginning of the space--they are necessarily part
1075 // of the dense prefix.
1076 size_t full_count = 0;
1077 const RegionData* cp;
1078 for (cp = beg_cp; cp < end_cp && cp->data_size() == region_size; ++cp) {
1079 ++full_count;
1080 }
1082 assert(total_invocations() >= _maximum_compaction_gc_num, "sanity");
1083 const size_t gcs_since_max = total_invocations() - _maximum_compaction_gc_num;
1084 const bool interval_ended = gcs_since_max > HeapMaximumCompactionInterval;
1085 if (maximum_compaction || cp == end_cp || interval_ended) {
1086 _maximum_compaction_gc_num = total_invocations();
1087 return sd.region_to_addr(cp);
1088 }
1090 HeapWord* const new_top = _space_info[id].new_top();
1091 const size_t space_live = pointer_delta(new_top, space->bottom());
1092 const size_t space_used = space->used_in_words();
1093 const size_t space_capacity = space->capacity_in_words();
1095 const double cur_density = double(space_live) / space_capacity;
1096 const double deadwood_density =
1097 (1.0 - cur_density) * (1.0 - cur_density) * cur_density * cur_density;
1098 const size_t deadwood_goal = size_t(space_capacity * deadwood_density);
1100 if (TraceParallelOldGCDensePrefix) {
1101 tty->print_cr("cur_dens=%5.3f dw_dens=%5.3f dw_goal=" SIZE_FORMAT,
1102 cur_density, deadwood_density, deadwood_goal);
1103 tty->print_cr("space_live=" SIZE_FORMAT " " "space_used=" SIZE_FORMAT " "
1104 "space_cap=" SIZE_FORMAT,
1105 space_live, space_used,
1106 space_capacity);
1107 }
1109 // XXX - Use binary search?
1110 HeapWord* dense_prefix = sd.region_to_addr(cp);
1111 const RegionData* full_cp = cp;
1112 const RegionData* const top_cp = sd.addr_to_region_ptr(space->top() - 1);
1113 while (cp < end_cp) {
1114 HeapWord* region_destination = cp->destination();
1115 const size_t cur_deadwood = pointer_delta(dense_prefix, region_destination);
1116 if (TraceParallelOldGCDensePrefix && Verbose) {
1117 tty->print_cr("c#=" SIZE_FORMAT_W(4) " dst=" PTR_FORMAT " "
1118 "dp=" SIZE_FORMAT_W(8) " " "cdw=" SIZE_FORMAT_W(8),
1119 sd.region(cp), region_destination,
1120 dense_prefix, cur_deadwood);
1121 }
1123 if (cur_deadwood >= deadwood_goal) {
1124 // Found the region that has the correct amount of deadwood to the left.
1125 // This typically occurs after crossing a fairly sparse set of regions, so
1126 // iterate backwards over those sparse regions, looking for the region
1127 // that has the lowest density of live objects 'to the right.'
1128 size_t space_to_left = sd.region(cp) * region_size;
1129 size_t live_to_left = space_to_left - cur_deadwood;
1130 size_t space_to_right = space_capacity - space_to_left;
1131 size_t live_to_right = space_live - live_to_left;
1132 double density_to_right = double(live_to_right) / space_to_right;
1133 while (cp > full_cp) {
1134 --cp;
1135 const size_t prev_region_live_to_right = live_to_right -
1136 cp->data_size();
1137 const size_t prev_region_space_to_right = space_to_right + region_size;
1138 double prev_region_density_to_right =
1139 double(prev_region_live_to_right) / prev_region_space_to_right;
1140 if (density_to_right <= prev_region_density_to_right) {
1141 return dense_prefix;
1142 }
1143 if (TraceParallelOldGCDensePrefix && Verbose) {
1144 tty->print_cr("backing up from c=" SIZE_FORMAT_W(4) " d2r=%10.8f "
1145 "pc_d2r=%10.8f", sd.region(cp), density_to_right,
1146 prev_region_density_to_right);
1147 }
1148 dense_prefix -= region_size;
1149 live_to_right = prev_region_live_to_right;
1150 space_to_right = prev_region_space_to_right;
1151 density_to_right = prev_region_density_to_right;
1152 }
1153 return dense_prefix;
1154 }
1156 dense_prefix += region_size;
1157 ++cp;
1158 }
1160 return dense_prefix;
1161 }
1163 #ifndef PRODUCT
1164 void PSParallelCompact::print_dense_prefix_stats(const char* const algorithm,
1165 const SpaceId id,
1166 const bool maximum_compaction,
1167 HeapWord* const addr)
1168 {
1169 const size_t region_idx = summary_data().addr_to_region_idx(addr);
1170 RegionData* const cp = summary_data().region(region_idx);
1171 const MutableSpace* const space = _space_info[id].space();
1172 HeapWord* const new_top = _space_info[id].new_top();
1174 const size_t space_live = pointer_delta(new_top, space->bottom());
1175 const size_t dead_to_left = pointer_delta(addr, cp->destination());
1176 const size_t space_cap = space->capacity_in_words();
1177 const double dead_to_left_pct = double(dead_to_left) / space_cap;
1178 const size_t live_to_right = new_top - cp->destination();
1179 const size_t dead_to_right = space->top() - addr - live_to_right;
1181 tty->print_cr("%s=" PTR_FORMAT " dpc=" SIZE_FORMAT_W(5) " "
1182 "spl=" SIZE_FORMAT " "
1183 "d2l=" SIZE_FORMAT " d2l%%=%6.4f "
1184 "d2r=" SIZE_FORMAT " l2r=" SIZE_FORMAT
1185 " ratio=%10.8f",
1186 algorithm, addr, region_idx,
1187 space_live,
1188 dead_to_left, dead_to_left_pct,
1189 dead_to_right, live_to_right,
1190 double(dead_to_right) / live_to_right);
1191 }
1192 #endif // #ifndef PRODUCT
1194 // Return a fraction indicating how much of the generation can be treated as
1195 // "dead wood" (i.e., not reclaimed). The function uses a normal distribution
1196 // based on the density of live objects in the generation to determine a limit,
1197 // which is then adjusted so the return value is min_percent when the density is
1198 // 1.
1199 //
1200 // The following table shows some return values for a different values of the
1201 // standard deviation (ParallelOldDeadWoodLimiterStdDev); the mean is 0.5 and
1202 // min_percent is 1.
1203 //
1204 // fraction allowed as dead wood
1205 // -----------------------------------------------------------------
1206 // density std_dev=70 std_dev=75 std_dev=80 std_dev=85 std_dev=90 std_dev=95
1207 // ------- ---------- ---------- ---------- ---------- ---------- ----------
1208 // 0.00000 0.01000000 0.01000000 0.01000000 0.01000000 0.01000000 0.01000000
1209 // 0.05000 0.03193096 0.02836880 0.02550828 0.02319280 0.02130337 0.01974941
1210 // 0.10000 0.05247504 0.04547452 0.03988045 0.03537016 0.03170171 0.02869272
1211 // 0.15000 0.07135702 0.06111390 0.05296419 0.04641639 0.04110601 0.03676066
1212 // 0.20000 0.08831616 0.07509618 0.06461766 0.05622444 0.04943437 0.04388975
1213 // 0.25000 0.10311208 0.08724696 0.07471205 0.06469760 0.05661313 0.05002313
1214 // 0.30000 0.11553050 0.09741183 0.08313394 0.07175114 0.06257797 0.05511132
1215 // 0.35000 0.12538832 0.10545958 0.08978741 0.07731366 0.06727491 0.05911289
1216 // 0.40000 0.13253818 0.11128511 0.09459590 0.08132834 0.07066107 0.06199500
1217 // 0.45000 0.13687208 0.11481163 0.09750361 0.08375387 0.07270534 0.06373386
1218 // 0.50000 0.13832410 0.11599237 0.09847664 0.08456518 0.07338887 0.06431510
1219 // 0.55000 0.13687208 0.11481163 0.09750361 0.08375387 0.07270534 0.06373386
1220 // 0.60000 0.13253818 0.11128511 0.09459590 0.08132834 0.07066107 0.06199500
1221 // 0.65000 0.12538832 0.10545958 0.08978741 0.07731366 0.06727491 0.05911289
1222 // 0.70000 0.11553050 0.09741183 0.08313394 0.07175114 0.06257797 0.05511132
1223 // 0.75000 0.10311208 0.08724696 0.07471205 0.06469760 0.05661313 0.05002313
1224 // 0.80000 0.08831616 0.07509618 0.06461766 0.05622444 0.04943437 0.04388975
1225 // 0.85000 0.07135702 0.06111390 0.05296419 0.04641639 0.04110601 0.03676066
1226 // 0.90000 0.05247504 0.04547452 0.03988045 0.03537016 0.03170171 0.02869272
1227 // 0.95000 0.03193096 0.02836880 0.02550828 0.02319280 0.02130337 0.01974941
1228 // 1.00000 0.01000000 0.01000000 0.01000000 0.01000000 0.01000000 0.01000000
1230 double PSParallelCompact::dead_wood_limiter(double density, size_t min_percent)
1231 {
1232 assert(_dwl_initialized, "uninitialized");
1234 // The raw limit is the value of the normal distribution at x = density.
1235 const double raw_limit = normal_distribution(density);
1237 // Adjust the raw limit so it becomes the minimum when the density is 1.
1238 //
1239 // First subtract the adjustment value (which is simply the precomputed value
1240 // normal_distribution(1.0)); this yields a value of 0 when the density is 1.
1241 // Then add the minimum value, so the minimum is returned when the density is
1242 // 1. Finally, prevent negative values, which occur when the mean is not 0.5.
1243 const double min = double(min_percent) / 100.0;
1244 const double limit = raw_limit - _dwl_adjustment + min;
1245 return MAX2(limit, 0.0);
1246 }
1248 ParallelCompactData::RegionData*
1249 PSParallelCompact::first_dead_space_region(const RegionData* beg,
1250 const RegionData* end)
1251 {
1252 const size_t region_size = ParallelCompactData::RegionSize;
1253 ParallelCompactData& sd = summary_data();
1254 size_t left = sd.region(beg);
1255 size_t right = end > beg ? sd.region(end) - 1 : left;
1257 // Binary search.
1258 while (left < right) {
1259 // Equivalent to (left + right) / 2, but does not overflow.
1260 const size_t middle = left + (right - left) / 2;
1261 RegionData* const middle_ptr = sd.region(middle);
1262 HeapWord* const dest = middle_ptr->destination();
1263 HeapWord* const addr = sd.region_to_addr(middle);
1264 assert(dest != NULL, "sanity");
1265 assert(dest <= addr, "must move left");
1267 if (middle > left && dest < addr) {
1268 right = middle - 1;
1269 } else if (middle < right && middle_ptr->data_size() == region_size) {
1270 left = middle + 1;
1271 } else {
1272 return middle_ptr;
1273 }
1274 }
1275 return sd.region(left);
1276 }
1278 ParallelCompactData::RegionData*
1279 PSParallelCompact::dead_wood_limit_region(const RegionData* beg,
1280 const RegionData* end,
1281 size_t dead_words)
1282 {
1283 ParallelCompactData& sd = summary_data();
1284 size_t left = sd.region(beg);
1285 size_t right = end > beg ? sd.region(end) - 1 : left;
1287 // Binary search.
1288 while (left < right) {
1289 // Equivalent to (left + right) / 2, but does not overflow.
1290 const size_t middle = left + (right - left) / 2;
1291 RegionData* const middle_ptr = sd.region(middle);
1292 HeapWord* const dest = middle_ptr->destination();
1293 HeapWord* const addr = sd.region_to_addr(middle);
1294 assert(dest != NULL, "sanity");
1295 assert(dest <= addr, "must move left");
1297 const size_t dead_to_left = pointer_delta(addr, dest);
1298 if (middle > left && dead_to_left > dead_words) {
1299 right = middle - 1;
1300 } else if (middle < right && dead_to_left < dead_words) {
1301 left = middle + 1;
1302 } else {
1303 return middle_ptr;
1304 }
1305 }
1306 return sd.region(left);
1307 }
1309 // The result is valid during the summary phase, after the initial summarization
1310 // of each space into itself, and before final summarization.
1311 inline double
1312 PSParallelCompact::reclaimed_ratio(const RegionData* const cp,
1313 HeapWord* const bottom,
1314 HeapWord* const top,
1315 HeapWord* const new_top)
1316 {
1317 ParallelCompactData& sd = summary_data();
1319 assert(cp != NULL, "sanity");
1320 assert(bottom != NULL, "sanity");
1321 assert(top != NULL, "sanity");
1322 assert(new_top != NULL, "sanity");
1323 assert(top >= new_top, "summary data problem?");
1324 assert(new_top > bottom, "space is empty; should not be here");
1325 assert(new_top >= cp->destination(), "sanity");
1326 assert(top >= sd.region_to_addr(cp), "sanity");
1328 HeapWord* const destination = cp->destination();
1329 const size_t dense_prefix_live = pointer_delta(destination, bottom);
1330 const size_t compacted_region_live = pointer_delta(new_top, destination);
1331 const size_t compacted_region_used = pointer_delta(top,
1332 sd.region_to_addr(cp));
1333 const size_t reclaimable = compacted_region_used - compacted_region_live;
1335 const double divisor = dense_prefix_live + 1.25 * compacted_region_live;
1336 return double(reclaimable) / divisor;
1337 }
1339 // Return the address of the end of the dense prefix, a.k.a. the start of the
1340 // compacted region. The address is always on a region boundary.
1341 //
1342 // Completely full regions at the left are skipped, since no compaction can
1343 // occur in those regions. Then the maximum amount of dead wood to allow is
1344 // computed, based on the density (amount live / capacity) of the generation;
1345 // the region with approximately that amount of dead space to the left is
1346 // identified as the limit region. Regions between the last completely full
1347 // region and the limit region are scanned and the one that has the best
1348 // (maximum) reclaimed_ratio() is selected.
1349 HeapWord*
1350 PSParallelCompact::compute_dense_prefix(const SpaceId id,
1351 bool maximum_compaction)
1352 {
1353 if (ParallelOldGCSplitALot) {
1354 if (_space_info[id].dense_prefix() != _space_info[id].space()->bottom()) {
1355 // The value was chosen to provoke splitting a young gen space; use it.
1356 return _space_info[id].dense_prefix();
1357 }
1358 }
1360 const size_t region_size = ParallelCompactData::RegionSize;
1361 const ParallelCompactData& sd = summary_data();
1363 const MutableSpace* const space = _space_info[id].space();
1364 HeapWord* const top = space->top();
1365 HeapWord* const top_aligned_up = sd.region_align_up(top);
1366 HeapWord* const new_top = _space_info[id].new_top();
1367 HeapWord* const new_top_aligned_up = sd.region_align_up(new_top);
1368 HeapWord* const bottom = space->bottom();
1369 const RegionData* const beg_cp = sd.addr_to_region_ptr(bottom);
1370 const RegionData* const top_cp = sd.addr_to_region_ptr(top_aligned_up);
1371 const RegionData* const new_top_cp =
1372 sd.addr_to_region_ptr(new_top_aligned_up);
1374 // Skip full regions at the beginning of the space--they are necessarily part
1375 // of the dense prefix.
1376 const RegionData* const full_cp = first_dead_space_region(beg_cp, new_top_cp);
1377 assert(full_cp->destination() == sd.region_to_addr(full_cp) ||
1378 space->is_empty(), "no dead space allowed to the left");
1379 assert(full_cp->data_size() < region_size || full_cp == new_top_cp - 1,
1380 "region must have dead space");
1382 // The gc number is saved whenever a maximum compaction is done, and used to
1383 // determine when the maximum compaction interval has expired. This avoids
1384 // successive max compactions for different reasons.
1385 assert(total_invocations() >= _maximum_compaction_gc_num, "sanity");
1386 const size_t gcs_since_max = total_invocations() - _maximum_compaction_gc_num;
1387 const bool interval_ended = gcs_since_max > HeapMaximumCompactionInterval ||
1388 total_invocations() == HeapFirstMaximumCompactionCount;
1389 if (maximum_compaction || full_cp == top_cp || interval_ended) {
1390 _maximum_compaction_gc_num = total_invocations();
1391 return sd.region_to_addr(full_cp);
1392 }
1394 const size_t space_live = pointer_delta(new_top, bottom);
1395 const size_t space_used = space->used_in_words();
1396 const size_t space_capacity = space->capacity_in_words();
1398 const double density = double(space_live) / double(space_capacity);
1399 const size_t min_percent_free = MarkSweepDeadRatio;
1400 const double limiter = dead_wood_limiter(density, min_percent_free);
1401 const size_t dead_wood_max = space_used - space_live;
1402 const size_t dead_wood_limit = MIN2(size_t(space_capacity * limiter),
1403 dead_wood_max);
1405 if (TraceParallelOldGCDensePrefix) {
1406 tty->print_cr("space_live=" SIZE_FORMAT " " "space_used=" SIZE_FORMAT " "
1407 "space_cap=" SIZE_FORMAT,
1408 space_live, space_used,
1409 space_capacity);
1410 tty->print_cr("dead_wood_limiter(%6.4f, %d)=%6.4f "
1411 "dead_wood_max=" SIZE_FORMAT " dead_wood_limit=" SIZE_FORMAT,
1412 density, min_percent_free, limiter,
1413 dead_wood_max, dead_wood_limit);
1414 }
1416 // Locate the region with the desired amount of dead space to the left.
1417 const RegionData* const limit_cp =
1418 dead_wood_limit_region(full_cp, top_cp, dead_wood_limit);
1420 // Scan from the first region with dead space to the limit region and find the
1421 // one with the best (largest) reclaimed ratio.
1422 double best_ratio = 0.0;
1423 const RegionData* best_cp = full_cp;
1424 for (const RegionData* cp = full_cp; cp < limit_cp; ++cp) {
1425 double tmp_ratio = reclaimed_ratio(cp, bottom, top, new_top);
1426 if (tmp_ratio > best_ratio) {
1427 best_cp = cp;
1428 best_ratio = tmp_ratio;
1429 }
1430 }
1432 #if 0
1433 // Something to consider: if the region with the best ratio is 'close to' the
1434 // first region w/free space, choose the first region with free space
1435 // ("first-free"). The first-free region is usually near the start of the
1436 // heap, which means we are copying most of the heap already, so copy a bit
1437 // more to get complete compaction.
1438 if (pointer_delta(best_cp, full_cp, sizeof(RegionData)) < 4) {
1439 _maximum_compaction_gc_num = total_invocations();
1440 best_cp = full_cp;
1441 }
1442 #endif // #if 0
1444 return sd.region_to_addr(best_cp);
1445 }
1447 #ifndef PRODUCT
1448 void
1449 PSParallelCompact::fill_with_live_objects(SpaceId id, HeapWord* const start,
1450 size_t words)
1451 {
1452 if (TraceParallelOldGCSummaryPhase) {
1453 tty->print_cr("fill_with_live_objects [" PTR_FORMAT " " PTR_FORMAT ") "
1454 SIZE_FORMAT, start, start + words, words);
1455 }
1457 ObjectStartArray* const start_array = _space_info[id].start_array();
1458 CollectedHeap::fill_with_objects(start, words);
1459 for (HeapWord* p = start; p < start + words; p += oop(p)->size()) {
1460 _mark_bitmap.mark_obj(p, words);
1461 _summary_data.add_obj(p, words);
1462 start_array->allocate_block(p);
1463 }
1464 }
1466 void
1467 PSParallelCompact::summarize_new_objects(SpaceId id, HeapWord* start)
1468 {
1469 ParallelCompactData& sd = summary_data();
1470 MutableSpace* space = _space_info[id].space();
1472 // Find the source and destination start addresses.
1473 HeapWord* const src_addr = sd.region_align_down(start);
1474 HeapWord* dst_addr;
1475 if (src_addr < start) {
1476 dst_addr = sd.addr_to_region_ptr(src_addr)->destination();
1477 } else if (src_addr > space->bottom()) {
1478 // The start (the original top() value) is aligned to a region boundary so
1479 // the associated region does not have a destination. Compute the
1480 // destination from the previous region.
1481 RegionData* const cp = sd.addr_to_region_ptr(src_addr) - 1;
1482 dst_addr = cp->destination() + cp->data_size();
1483 } else {
1484 // Filling the entire space.
1485 dst_addr = space->bottom();
1486 }
1487 assert(dst_addr != NULL, "sanity");
1489 // Update the summary data.
1490 bool result = _summary_data.summarize(_space_info[id].split_info(),
1491 src_addr, space->top(), NULL,
1492 dst_addr, space->end(),
1493 _space_info[id].new_top_addr());
1494 assert(result, "should not fail: bad filler object size");
1495 }
1497 void
1498 PSParallelCompact::provoke_split_fill_survivor(SpaceId id)
1499 {
1500 if (total_invocations() % (ParallelOldGCSplitInterval * 3) != 0) {
1501 return;
1502 }
1504 MutableSpace* const space = _space_info[id].space();
1505 if (space->is_empty()) {
1506 HeapWord* b = space->bottom();
1507 HeapWord* t = b + space->capacity_in_words() / 2;
1508 space->set_top(t);
1509 if (ZapUnusedHeapArea) {
1510 space->set_top_for_allocations();
1511 }
1513 size_t min_size = CollectedHeap::min_fill_size();
1514 size_t obj_len = min_size;
1515 while (b + obj_len <= t) {
1516 CollectedHeap::fill_with_object(b, obj_len);
1517 mark_bitmap()->mark_obj(b, obj_len);
1518 summary_data().add_obj(b, obj_len);
1519 b += obj_len;
1520 obj_len = (obj_len & (min_size*3)) + min_size; // 8 16 24 32 8 16 24 32 ...
1521 }
1522 if (b < t) {
1523 // The loop didn't completely fill to t (top); adjust top downward.
1524 space->set_top(b);
1525 if (ZapUnusedHeapArea) {
1526 space->set_top_for_allocations();
1527 }
1528 }
1530 HeapWord** nta = _space_info[id].new_top_addr();
1531 bool result = summary_data().summarize(_space_info[id].split_info(),
1532 space->bottom(), space->top(), NULL,
1533 space->bottom(), space->end(), nta);
1534 assert(result, "space must fit into itself");
1535 }
1536 }
1538 void
1539 PSParallelCompact::provoke_split(bool & max_compaction)
1540 {
1541 if (total_invocations() % ParallelOldGCSplitInterval != 0) {
1542 return;
1543 }
1545 const size_t region_size = ParallelCompactData::RegionSize;
1546 ParallelCompactData& sd = summary_data();
1548 MutableSpace* const eden_space = _space_info[eden_space_id].space();
1549 MutableSpace* const from_space = _space_info[from_space_id].space();
1550 const size_t eden_live = pointer_delta(eden_space->top(),
1551 _space_info[eden_space_id].new_top());
1552 const size_t from_live = pointer_delta(from_space->top(),
1553 _space_info[from_space_id].new_top());
1555 const size_t min_fill_size = CollectedHeap::min_fill_size();
1556 const size_t eden_free = pointer_delta(eden_space->end(), eden_space->top());
1557 const size_t eden_fillable = eden_free >= min_fill_size ? eden_free : 0;
1558 const size_t from_free = pointer_delta(from_space->end(), from_space->top());
1559 const size_t from_fillable = from_free >= min_fill_size ? from_free : 0;
1561 // Choose the space to split; need at least 2 regions live (or fillable).
1562 SpaceId id;
1563 MutableSpace* space;
1564 size_t live_words;
1565 size_t fill_words;
1566 if (eden_live + eden_fillable >= region_size * 2) {
1567 id = eden_space_id;
1568 space = eden_space;
1569 live_words = eden_live;
1570 fill_words = eden_fillable;
1571 } else if (from_live + from_fillable >= region_size * 2) {
1572 id = from_space_id;
1573 space = from_space;
1574 live_words = from_live;
1575 fill_words = from_fillable;
1576 } else {
1577 return; // Give up.
1578 }
1579 assert(fill_words == 0 || fill_words >= min_fill_size, "sanity");
1581 if (live_words < region_size * 2) {
1582 // Fill from top() to end() w/live objects of mixed sizes.
1583 HeapWord* const fill_start = space->top();
1584 live_words += fill_words;
1586 space->set_top(fill_start + fill_words);
1587 if (ZapUnusedHeapArea) {
1588 space->set_top_for_allocations();
1589 }
1591 HeapWord* cur_addr = fill_start;
1592 while (fill_words > 0) {
1593 const size_t r = (size_t)os::random() % (region_size / 2) + min_fill_size;
1594 size_t cur_size = MIN2(align_object_size_(r), fill_words);
1595 if (fill_words - cur_size < min_fill_size) {
1596 cur_size = fill_words; // Avoid leaving a fragment too small to fill.
1597 }
1599 CollectedHeap::fill_with_object(cur_addr, cur_size);
1600 mark_bitmap()->mark_obj(cur_addr, cur_size);
1601 sd.add_obj(cur_addr, cur_size);
1603 cur_addr += cur_size;
1604 fill_words -= cur_size;
1605 }
1607 summarize_new_objects(id, fill_start);
1608 }
1610 max_compaction = false;
1612 // Manipulate the old gen so that it has room for about half of the live data
1613 // in the target young gen space (live_words / 2).
1614 id = old_space_id;
1615 space = _space_info[id].space();
1616 const size_t free_at_end = space->free_in_words();
1617 const size_t free_target = align_object_size(live_words / 2);
1618 const size_t dead = pointer_delta(space->top(), _space_info[id].new_top());
1620 if (free_at_end >= free_target + min_fill_size) {
1621 // Fill space above top() and set the dense prefix so everything survives.
1622 HeapWord* const fill_start = space->top();
1623 const size_t fill_size = free_at_end - free_target;
1624 space->set_top(space->top() + fill_size);
1625 if (ZapUnusedHeapArea) {
1626 space->set_top_for_allocations();
1627 }
1628 fill_with_live_objects(id, fill_start, fill_size);
1629 summarize_new_objects(id, fill_start);
1630 _space_info[id].set_dense_prefix(sd.region_align_down(space->top()));
1631 } else if (dead + free_at_end > free_target) {
1632 // Find a dense prefix that makes the right amount of space available.
1633 HeapWord* cur = sd.region_align_down(space->top());
1634 HeapWord* cur_destination = sd.addr_to_region_ptr(cur)->destination();
1635 size_t dead_to_right = pointer_delta(space->end(), cur_destination);
1636 while (dead_to_right < free_target) {
1637 cur -= region_size;
1638 cur_destination = sd.addr_to_region_ptr(cur)->destination();
1639 dead_to_right = pointer_delta(space->end(), cur_destination);
1640 }
1641 _space_info[id].set_dense_prefix(cur);
1642 }
1643 }
1644 #endif // #ifndef PRODUCT
1646 void PSParallelCompact::summarize_spaces_quick()
1647 {
1648 for (unsigned int i = 0; i < last_space_id; ++i) {
1649 const MutableSpace* space = _space_info[i].space();
1650 HeapWord** nta = _space_info[i].new_top_addr();
1651 bool result = _summary_data.summarize(_space_info[i].split_info(),
1652 space->bottom(), space->top(), NULL,
1653 space->bottom(), space->end(), nta);
1654 assert(result, "space must fit into itself");
1655 _space_info[i].set_dense_prefix(space->bottom());
1656 }
1658 #ifndef PRODUCT
1659 if (ParallelOldGCSplitALot) {
1660 provoke_split_fill_survivor(to_space_id);
1661 }
1662 #endif // #ifndef PRODUCT
1663 }
1665 void PSParallelCompact::fill_dense_prefix_end(SpaceId id)
1666 {
1667 HeapWord* const dense_prefix_end = dense_prefix(id);
1668 const RegionData* region = _summary_data.addr_to_region_ptr(dense_prefix_end);
1669 const idx_t dense_prefix_bit = _mark_bitmap.addr_to_bit(dense_prefix_end);
1670 if (dead_space_crosses_boundary(region, dense_prefix_bit)) {
1671 // Only enough dead space is filled so that any remaining dead space to the
1672 // left is larger than the minimum filler object. (The remainder is filled
1673 // during the copy/update phase.)
1674 //
1675 // The size of the dead space to the right of the boundary is not a
1676 // concern, since compaction will be able to use whatever space is
1677 // available.
1678 //
1679 // Here '||' is the boundary, 'x' represents a don't care bit and a box
1680 // surrounds the space to be filled with an object.
1681 //
1682 // In the 32-bit VM, each bit represents two 32-bit words:
1683 // +---+
1684 // a) beg_bits: ... x x x | 0 | || 0 x x ...
1685 // end_bits: ... x x x | 0 | || 0 x x ...
1686 // +---+
1687 //
1688 // In the 64-bit VM, each bit represents one 64-bit word:
1689 // +------------+
1690 // b) beg_bits: ... x x x | 0 || 0 | x x ...
1691 // end_bits: ... x x 1 | 0 || 0 | x x ...
1692 // +------------+
1693 // +-------+
1694 // c) beg_bits: ... x x | 0 0 | || 0 x x ...
1695 // end_bits: ... x 1 | 0 0 | || 0 x x ...
1696 // +-------+
1697 // +-----------+
1698 // d) beg_bits: ... x | 0 0 0 | || 0 x x ...
1699 // end_bits: ... 1 | 0 0 0 | || 0 x x ...
1700 // +-----------+
1701 // +-------+
1702 // e) beg_bits: ... 0 0 | 0 0 | || 0 x x ...
1703 // end_bits: ... 0 0 | 0 0 | || 0 x x ...
1704 // +-------+
1706 // Initially assume case a, c or e will apply.
1707 size_t obj_len = CollectedHeap::min_fill_size();
1708 HeapWord* obj_beg = dense_prefix_end - obj_len;
1710 #ifdef _LP64
1711 if (MinObjAlignment > 1) { // object alignment > heap word size
1712 // Cases a, c or e.
1713 } else if (_mark_bitmap.is_obj_end(dense_prefix_bit - 2)) {
1714 // Case b above.
1715 obj_beg = dense_prefix_end - 1;
1716 } else if (!_mark_bitmap.is_obj_end(dense_prefix_bit - 3) &&
1717 _mark_bitmap.is_obj_end(dense_prefix_bit - 4)) {
1718 // Case d above.
1719 obj_beg = dense_prefix_end - 3;
1720 obj_len = 3;
1721 }
1722 #endif // #ifdef _LP64
1724 CollectedHeap::fill_with_object(obj_beg, obj_len);
1725 _mark_bitmap.mark_obj(obj_beg, obj_len);
1726 _summary_data.add_obj(obj_beg, obj_len);
1727 assert(start_array(id) != NULL, "sanity");
1728 start_array(id)->allocate_block(obj_beg);
1729 }
1730 }
1732 void
1733 PSParallelCompact::clear_source_region(HeapWord* beg_addr, HeapWord* end_addr)
1734 {
1735 RegionData* const beg_ptr = _summary_data.addr_to_region_ptr(beg_addr);
1736 HeapWord* const end_aligned_up = _summary_data.region_align_up(end_addr);
1737 RegionData* const end_ptr = _summary_data.addr_to_region_ptr(end_aligned_up);
1738 for (RegionData* cur = beg_ptr; cur < end_ptr; ++cur) {
1739 cur->set_source_region(0);
1740 }
1741 }
1743 void
1744 PSParallelCompact::summarize_space(SpaceId id, bool maximum_compaction)
1745 {
1746 assert(id < last_space_id, "id out of range");
1747 assert(_space_info[id].dense_prefix() == _space_info[id].space()->bottom() ||
1748 ParallelOldGCSplitALot && id == old_space_id,
1749 "should have been reset in summarize_spaces_quick()");
1751 const MutableSpace* space = _space_info[id].space();
1752 if (_space_info[id].new_top() != space->bottom()) {
1753 HeapWord* dense_prefix_end = compute_dense_prefix(id, maximum_compaction);
1754 _space_info[id].set_dense_prefix(dense_prefix_end);
1756 #ifndef PRODUCT
1757 if (TraceParallelOldGCDensePrefix) {
1758 print_dense_prefix_stats("ratio", id, maximum_compaction,
1759 dense_prefix_end);
1760 HeapWord* addr = compute_dense_prefix_via_density(id, maximum_compaction);
1761 print_dense_prefix_stats("density", id, maximum_compaction, addr);
1762 }
1763 #endif // #ifndef PRODUCT
1765 // Recompute the summary data, taking into account the dense prefix. If
1766 // every last byte will be reclaimed, then the existing summary data which
1767 // compacts everything can be left in place.
1768 if (!maximum_compaction && dense_prefix_end != space->bottom()) {
1769 // If dead space crosses the dense prefix boundary, it is (at least
1770 // partially) filled with a dummy object, marked live and added to the
1771 // summary data. This simplifies the copy/update phase and must be done
1772 // before the final locations of objects are determined, to prevent
1773 // leaving a fragment of dead space that is too small to fill.
1774 fill_dense_prefix_end(id);
1776 // Compute the destination of each Region, and thus each object.
1777 _summary_data.summarize_dense_prefix(space->bottom(), dense_prefix_end);
1778 _summary_data.summarize(_space_info[id].split_info(),
1779 dense_prefix_end, space->top(), NULL,
1780 dense_prefix_end, space->end(),
1781 _space_info[id].new_top_addr());
1782 }
1783 }
1785 if (TraceParallelOldGCSummaryPhase) {
1786 const size_t region_size = ParallelCompactData::RegionSize;
1787 HeapWord* const dense_prefix_end = _space_info[id].dense_prefix();
1788 const size_t dp_region = _summary_data.addr_to_region_idx(dense_prefix_end);
1789 const size_t dp_words = pointer_delta(dense_prefix_end, space->bottom());
1790 HeapWord* const new_top = _space_info[id].new_top();
1791 const HeapWord* nt_aligned_up = _summary_data.region_align_up(new_top);
1792 const size_t cr_words = pointer_delta(nt_aligned_up, dense_prefix_end);
1793 tty->print_cr("id=%d cap=" SIZE_FORMAT " dp=" PTR_FORMAT " "
1794 "dp_region=" SIZE_FORMAT " " "dp_count=" SIZE_FORMAT " "
1795 "cr_count=" SIZE_FORMAT " " "nt=" PTR_FORMAT,
1796 id, space->capacity_in_words(), dense_prefix_end,
1797 dp_region, dp_words / region_size,
1798 cr_words / region_size, new_top);
1799 }
1800 }
1802 #ifndef PRODUCT
1803 void PSParallelCompact::summary_phase_msg(SpaceId dst_space_id,
1804 HeapWord* dst_beg, HeapWord* dst_end,
1805 SpaceId src_space_id,
1806 HeapWord* src_beg, HeapWord* src_end)
1807 {
1808 if (TraceParallelOldGCSummaryPhase) {
1809 tty->print_cr("summarizing %d [%s] into %d [%s]: "
1810 "src=" PTR_FORMAT "-" PTR_FORMAT " "
1811 SIZE_FORMAT "-" SIZE_FORMAT " "
1812 "dst=" PTR_FORMAT "-" PTR_FORMAT " "
1813 SIZE_FORMAT "-" SIZE_FORMAT,
1814 src_space_id, space_names[src_space_id],
1815 dst_space_id, space_names[dst_space_id],
1816 src_beg, src_end,
1817 _summary_data.addr_to_region_idx(src_beg),
1818 _summary_data.addr_to_region_idx(src_end),
1819 dst_beg, dst_end,
1820 _summary_data.addr_to_region_idx(dst_beg),
1821 _summary_data.addr_to_region_idx(dst_end));
1822 }
1823 }
1824 #endif // #ifndef PRODUCT
1826 void PSParallelCompact::summary_phase(ParCompactionManager* cm,
1827 bool maximum_compaction)
1828 {
1829 TraceTime tm("summary phase", print_phases(), true, gclog_or_tty);
1830 // trace("2");
1832 #ifdef ASSERT
1833 if (TraceParallelOldGCMarkingPhase) {
1834 tty->print_cr("add_obj_count=" SIZE_FORMAT " "
1835 "add_obj_bytes=" SIZE_FORMAT,
1836 add_obj_count, add_obj_size * HeapWordSize);
1837 tty->print_cr("mark_bitmap_count=" SIZE_FORMAT " "
1838 "mark_bitmap_bytes=" SIZE_FORMAT,
1839 mark_bitmap_count, mark_bitmap_size * HeapWordSize);
1840 }
1841 #endif // #ifdef ASSERT
1843 // Quick summarization of each space into itself, to see how much is live.
1844 summarize_spaces_quick();
1846 if (TraceParallelOldGCSummaryPhase) {
1847 tty->print_cr("summary_phase: after summarizing each space to self");
1848 Universe::print();
1849 NOT_PRODUCT(print_region_ranges());
1850 if (Verbose) {
1851 NOT_PRODUCT(print_initial_summary_data(_summary_data, _space_info));
1852 }
1853 }
1855 // The amount of live data that will end up in old space (assuming it fits).
1856 size_t old_space_total_live = 0;
1857 for (unsigned int id = old_space_id; id < last_space_id; ++id) {
1858 old_space_total_live += pointer_delta(_space_info[id].new_top(),
1859 _space_info[id].space()->bottom());
1860 }
1862 MutableSpace* const old_space = _space_info[old_space_id].space();
1863 const size_t old_capacity = old_space->capacity_in_words();
1864 if (old_space_total_live > old_capacity) {
1865 // XXX - should also try to expand
1866 maximum_compaction = true;
1867 }
1868 #ifndef PRODUCT
1869 if (ParallelOldGCSplitALot && old_space_total_live < old_capacity) {
1870 provoke_split(maximum_compaction);
1871 }
1872 #endif // #ifndef PRODUCT
1874 // Old generations.
1875 summarize_space(old_space_id, maximum_compaction);
1877 // Summarize the remaining spaces in the young gen. The initial target space
1878 // is the old gen. If a space does not fit entirely into the target, then the
1879 // remainder is compacted into the space itself and that space becomes the new
1880 // target.
1881 SpaceId dst_space_id = old_space_id;
1882 HeapWord* dst_space_end = old_space->end();
1883 HeapWord** new_top_addr = _space_info[dst_space_id].new_top_addr();
1884 for (unsigned int id = eden_space_id; id < last_space_id; ++id) {
1885 const MutableSpace* space = _space_info[id].space();
1886 const size_t live = pointer_delta(_space_info[id].new_top(),
1887 space->bottom());
1888 const size_t available = pointer_delta(dst_space_end, *new_top_addr);
1890 NOT_PRODUCT(summary_phase_msg(dst_space_id, *new_top_addr, dst_space_end,
1891 SpaceId(id), space->bottom(), space->top());)
1892 if (live > 0 && live <= available) {
1893 // All the live data will fit.
1894 bool done = _summary_data.summarize(_space_info[id].split_info(),
1895 space->bottom(), space->top(),
1896 NULL,
1897 *new_top_addr, dst_space_end,
1898 new_top_addr);
1899 assert(done, "space must fit into old gen");
1901 // Reset the new_top value for the space.
1902 _space_info[id].set_new_top(space->bottom());
1903 } else if (live > 0) {
1904 // Attempt to fit part of the source space into the target space.
1905 HeapWord* next_src_addr = NULL;
1906 bool done = _summary_data.summarize(_space_info[id].split_info(),
1907 space->bottom(), space->top(),
1908 &next_src_addr,
1909 *new_top_addr, dst_space_end,
1910 new_top_addr);
1911 assert(!done, "space should not fit into old gen");
1912 assert(next_src_addr != NULL, "sanity");
1914 // The source space becomes the new target, so the remainder is compacted
1915 // within the space itself.
1916 dst_space_id = SpaceId(id);
1917 dst_space_end = space->end();
1918 new_top_addr = _space_info[id].new_top_addr();
1919 NOT_PRODUCT(summary_phase_msg(dst_space_id,
1920 space->bottom(), dst_space_end,
1921 SpaceId(id), next_src_addr, space->top());)
1922 done = _summary_data.summarize(_space_info[id].split_info(),
1923 next_src_addr, space->top(),
1924 NULL,
1925 space->bottom(), dst_space_end,
1926 new_top_addr);
1927 assert(done, "space must fit when compacted into itself");
1928 assert(*new_top_addr <= space->top(), "usage should not grow");
1929 }
1930 }
1932 if (TraceParallelOldGCSummaryPhase) {
1933 tty->print_cr("summary_phase: after final summarization");
1934 Universe::print();
1935 NOT_PRODUCT(print_region_ranges());
1936 if (Verbose) {
1937 NOT_PRODUCT(print_generic_summary_data(_summary_data, _space_info));
1938 }
1939 }
1940 }
1942 // This method should contain all heap-specific policy for invoking a full
1943 // collection. invoke_no_policy() will only attempt to compact the heap; it
1944 // will do nothing further. If we need to bail out for policy reasons, scavenge
1945 // before full gc, or any other specialized behavior, it needs to be added here.
1946 //
1947 // Note that this method should only be called from the vm_thread while at a
1948 // safepoint.
1949 //
1950 // Note that the all_soft_refs_clear flag in the collector policy
1951 // may be true because this method can be called without intervening
1952 // activity. For example when the heap space is tight and full measure
1953 // are being taken to free space.
1954 void PSParallelCompact::invoke(bool maximum_heap_compaction) {
1955 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
1956 assert(Thread::current() == (Thread*)VMThread::vm_thread(),
1957 "should be in vm thread");
1959 ParallelScavengeHeap* heap = gc_heap();
1960 GCCause::Cause gc_cause = heap->gc_cause();
1961 assert(!heap->is_gc_active(), "not reentrant");
1963 PSAdaptiveSizePolicy* policy = heap->size_policy();
1964 IsGCActiveMark mark;
1966 if (ScavengeBeforeFullGC) {
1967 PSScavenge::invoke_no_policy();
1968 }
1970 const bool clear_all_soft_refs =
1971 heap->collector_policy()->should_clear_all_soft_refs();
1973 PSParallelCompact::invoke_no_policy(clear_all_soft_refs ||
1974 maximum_heap_compaction);
1975 }
1977 bool ParallelCompactData::region_contains(size_t region_index, HeapWord* addr) {
1978 size_t addr_region_index = addr_to_region_idx(addr);
1979 return region_index == addr_region_index;
1980 }
1982 // This method contains no policy. You should probably
1983 // be calling invoke() instead.
1984 bool PSParallelCompact::invoke_no_policy(bool maximum_heap_compaction) {
1985 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
1986 assert(ref_processor() != NULL, "Sanity");
1988 if (GC_locker::check_active_before_gc()) {
1989 return false;
1990 }
1992 TimeStamp marking_start;
1993 TimeStamp compaction_start;
1994 TimeStamp collection_exit;
1996 ParallelScavengeHeap* heap = gc_heap();
1997 GCCause::Cause gc_cause = heap->gc_cause();
1998 PSYoungGen* young_gen = heap->young_gen();
1999 PSOldGen* old_gen = heap->old_gen();
2000 PSAdaptiveSizePolicy* size_policy = heap->size_policy();
2002 // The scope of casr should end after code that can change
2003 // CollectorPolicy::_should_clear_all_soft_refs.
2004 ClearedAllSoftRefs casr(maximum_heap_compaction,
2005 heap->collector_policy());
2007 if (ZapUnusedHeapArea) {
2008 // Save information needed to minimize mangling
2009 heap->record_gen_tops_before_GC();
2010 }
2012 heap->pre_full_gc_dump();
2014 _print_phases = PrintGCDetails && PrintParallelOldGCPhaseTimes;
2016 // Make sure data structures are sane, make the heap parsable, and do other
2017 // miscellaneous bookkeeping.
2018 PreGCValues pre_gc_values;
2019 pre_compact(&pre_gc_values);
2021 // Get the compaction manager reserved for the VM thread.
2022 ParCompactionManager* const vmthread_cm =
2023 ParCompactionManager::manager_array(gc_task_manager()->workers());
2025 // Place after pre_compact() where the number of invocations is incremented.
2026 AdaptiveSizePolicyOutput(size_policy, heap->total_collections());
2028 {
2029 ResourceMark rm;
2030 HandleMark hm;
2032 // Set the number of GC threads to be used in this collection
2033 gc_task_manager()->set_active_gang();
2034 gc_task_manager()->task_idle_workers();
2035 heap->set_par_threads(gc_task_manager()->active_workers());
2037 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
2038 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
2039 TraceTime t1(GCCauseString("Full GC", gc_cause), PrintGC, !PrintGCDetails, gclog_or_tty);
2040 TraceCollectorStats tcs(counters());
2041 TraceMemoryManagerStats tms(true /* Full GC */,gc_cause);
2043 if (TraceGen1Time) accumulated_time()->start();
2045 // Let the size policy know we're starting
2046 size_policy->major_collection_begin();
2048 CodeCache::gc_prologue();
2049 Threads::gc_prologue();
2051 COMPILER2_PRESENT(DerivedPointerTable::clear());
2053 ref_processor()->enable_discovery(true /*verify_disabled*/, true /*verify_no_refs*/);
2054 ref_processor()->setup_policy(maximum_heap_compaction);
2056 bool marked_for_unloading = false;
2058 marking_start.update();
2059 marking_phase(vmthread_cm, maximum_heap_compaction);
2061 #ifndef PRODUCT
2062 if (TraceParallelOldGCMarkingPhase) {
2063 gclog_or_tty->print_cr("marking_phase: cas_tries %d cas_retries %d "
2064 "cas_by_another %d",
2065 mark_bitmap()->cas_tries(), mark_bitmap()->cas_retries(),
2066 mark_bitmap()->cas_by_another());
2067 }
2068 #endif // #ifndef PRODUCT
2070 bool max_on_system_gc = UseMaximumCompactionOnSystemGC
2071 && gc_cause == GCCause::_java_lang_system_gc;
2072 summary_phase(vmthread_cm, maximum_heap_compaction || max_on_system_gc);
2074 COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity"));
2075 COMPILER2_PRESENT(DerivedPointerTable::set_active(false));
2077 // adjust_roots() updates Universe::_intArrayKlassObj which is
2078 // needed by the compaction for filling holes in the dense prefix.
2079 adjust_roots();
2081 compaction_start.update();
2082 compact();
2084 // Reset the mark bitmap, summary data, and do other bookkeeping. Must be
2085 // done before resizing.
2086 post_compact();
2088 // Let the size policy know we're done
2089 size_policy->major_collection_end(old_gen->used_in_bytes(), gc_cause);
2091 if (UseAdaptiveSizePolicy) {
2092 if (PrintAdaptiveSizePolicy) {
2093 gclog_or_tty->print("AdaptiveSizeStart: ");
2094 gclog_or_tty->stamp();
2095 gclog_or_tty->print_cr(" collection: %d ",
2096 heap->total_collections());
2097 if (Verbose) {
2098 gclog_or_tty->print("old_gen_capacity: %d young_gen_capacity: %d",
2099 old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes());
2100 }
2101 }
2103 // Don't check if the size_policy is ready here. Let
2104 // the size_policy check that internally.
2105 if (UseAdaptiveGenerationSizePolicyAtMajorCollection &&
2106 ((gc_cause != GCCause::_java_lang_system_gc) ||
2107 UseAdaptiveSizePolicyWithSystemGC)) {
2108 // Calculate optimal free space amounts
2109 assert(young_gen->max_size() >
2110 young_gen->from_space()->capacity_in_bytes() +
2111 young_gen->to_space()->capacity_in_bytes(),
2112 "Sizes of space in young gen are out-of-bounds");
2113 size_t max_eden_size = young_gen->max_size() -
2114 young_gen->from_space()->capacity_in_bytes() -
2115 young_gen->to_space()->capacity_in_bytes();
2116 size_policy->compute_generation_free_space(
2117 young_gen->used_in_bytes(),
2118 young_gen->eden_space()->used_in_bytes(),
2119 old_gen->used_in_bytes(),
2120 young_gen->eden_space()->capacity_in_bytes(),
2121 old_gen->max_gen_size(),
2122 max_eden_size,
2123 true /* full gc*/,
2124 gc_cause,
2125 heap->collector_policy());
2127 heap->resize_old_gen(
2128 size_policy->calculated_old_free_size_in_bytes());
2130 // Don't resize the young generation at an major collection. A
2131 // desired young generation size may have been calculated but
2132 // resizing the young generation complicates the code because the
2133 // resizing of the old generation may have moved the boundary
2134 // between the young generation and the old generation. Let the
2135 // young generation resizing happen at the minor collections.
2136 }
2137 if (PrintAdaptiveSizePolicy) {
2138 gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ",
2139 heap->total_collections());
2140 }
2141 }
2143 if (UsePerfData) {
2144 PSGCAdaptivePolicyCounters* const counters = heap->gc_policy_counters();
2145 counters->update_counters();
2146 counters->update_old_capacity(old_gen->capacity_in_bytes());
2147 counters->update_young_capacity(young_gen->capacity_in_bytes());
2148 }
2150 heap->resize_all_tlabs();
2152 // Resize the metaspace capactiy after a collection
2153 MetaspaceGC::compute_new_size();
2155 if (TraceGen1Time) accumulated_time()->stop();
2157 if (PrintGC) {
2158 if (PrintGCDetails) {
2159 // No GC timestamp here. This is after GC so it would be confusing.
2160 young_gen->print_used_change(pre_gc_values.young_gen_used());
2161 old_gen->print_used_change(pre_gc_values.old_gen_used());
2162 heap->print_heap_change(pre_gc_values.heap_used());
2163 MetaspaceAux::print_metaspace_change(pre_gc_values.metadata_used());
2164 } else {
2165 heap->print_heap_change(pre_gc_values.heap_used());
2166 }
2167 }
2169 // Track memory usage and detect low memory
2170 MemoryService::track_memory_usage();
2171 heap->update_counters();
2172 gc_task_manager()->release_idle_workers();
2173 }
2175 #ifdef ASSERT
2176 for (size_t i = 0; i < ParallelGCThreads + 1; ++i) {
2177 ParCompactionManager* const cm =
2178 ParCompactionManager::manager_array(int(i));
2179 assert(cm->marking_stack()->is_empty(), "should be empty");
2180 assert(ParCompactionManager::region_list(int(i))->is_empty(), "should be empty");
2181 }
2182 #endif // ASSERT
2184 if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) {
2185 HandleMark hm; // Discard invalid handles created during verification
2186 gclog_or_tty->print(" VerifyAfterGC:");
2187 Universe::verify(false);
2188 }
2190 // Re-verify object start arrays
2191 if (VerifyObjectStartArray &&
2192 VerifyAfterGC) {
2193 old_gen->verify_object_start_array();
2194 }
2196 if (ZapUnusedHeapArea) {
2197 old_gen->object_space()->check_mangled_unused_area_complete();
2198 }
2200 NOT_PRODUCT(ref_processor()->verify_no_references_recorded());
2202 collection_exit.update();
2204 heap->print_heap_after_gc();
2205 if (PrintGCTaskTimeStamps) {
2206 gclog_or_tty->print_cr("VM-Thread " INT64_FORMAT " " INT64_FORMAT " "
2207 INT64_FORMAT,
2208 marking_start.ticks(), compaction_start.ticks(),
2209 collection_exit.ticks());
2210 gc_task_manager()->print_task_time_stamps();
2211 }
2213 heap->post_full_gc_dump();
2215 #ifdef TRACESPINNING
2216 ParallelTaskTerminator::print_termination_counts();
2217 #endif
2219 return true;
2220 }
2222 bool PSParallelCompact::absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy,
2223 PSYoungGen* young_gen,
2224 PSOldGen* old_gen) {
2225 MutableSpace* const eden_space = young_gen->eden_space();
2226 assert(!eden_space->is_empty(), "eden must be non-empty");
2227 assert(young_gen->virtual_space()->alignment() ==
2228 old_gen->virtual_space()->alignment(), "alignments do not match");
2230 if (!(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary)) {
2231 return false;
2232 }
2234 // Both generations must be completely committed.
2235 if (young_gen->virtual_space()->uncommitted_size() != 0) {
2236 return false;
2237 }
2238 if (old_gen->virtual_space()->uncommitted_size() != 0) {
2239 return false;
2240 }
2242 // Figure out how much to take from eden. Include the average amount promoted
2243 // in the total; otherwise the next young gen GC will simply bail out to a
2244 // full GC.
2245 const size_t alignment = old_gen->virtual_space()->alignment();
2246 const size_t eden_used = eden_space->used_in_bytes();
2247 const size_t promoted = (size_t)size_policy->avg_promoted()->padded_average();
2248 const size_t absorb_size = align_size_up(eden_used + promoted, alignment);
2249 const size_t eden_capacity = eden_space->capacity_in_bytes();
2251 if (absorb_size >= eden_capacity) {
2252 return false; // Must leave some space in eden.
2253 }
2255 const size_t new_young_size = young_gen->capacity_in_bytes() - absorb_size;
2256 if (new_young_size < young_gen->min_gen_size()) {
2257 return false; // Respect young gen minimum size.
2258 }
2260 if (TraceAdaptiveGCBoundary && Verbose) {
2261 gclog_or_tty->print(" absorbing " SIZE_FORMAT "K: "
2262 "eden " SIZE_FORMAT "K->" SIZE_FORMAT "K "
2263 "from " SIZE_FORMAT "K, to " SIZE_FORMAT "K "
2264 "young_gen " SIZE_FORMAT "K->" SIZE_FORMAT "K ",
2265 absorb_size / K,
2266 eden_capacity / K, (eden_capacity - absorb_size) / K,
2267 young_gen->from_space()->used_in_bytes() / K,
2268 young_gen->to_space()->used_in_bytes() / K,
2269 young_gen->capacity_in_bytes() / K, new_young_size / K);
2270 }
2272 // Fill the unused part of the old gen.
2273 MutableSpace* const old_space = old_gen->object_space();
2274 HeapWord* const unused_start = old_space->top();
2275 size_t const unused_words = pointer_delta(old_space->end(), unused_start);
2277 if (unused_words > 0) {
2278 if (unused_words < CollectedHeap::min_fill_size()) {
2279 return false; // If the old gen cannot be filled, must give up.
2280 }
2281 CollectedHeap::fill_with_objects(unused_start, unused_words);
2282 }
2284 // Take the live data from eden and set both top and end in the old gen to
2285 // eden top. (Need to set end because reset_after_change() mangles the region
2286 // from end to virtual_space->high() in debug builds).
2287 HeapWord* const new_top = eden_space->top();
2288 old_gen->virtual_space()->expand_into(young_gen->virtual_space(),
2289 absorb_size);
2290 young_gen->reset_after_change();
2291 old_space->set_top(new_top);
2292 old_space->set_end(new_top);
2293 old_gen->reset_after_change();
2295 // Update the object start array for the filler object and the data from eden.
2296 ObjectStartArray* const start_array = old_gen->start_array();
2297 for (HeapWord* p = unused_start; p < new_top; p += oop(p)->size()) {
2298 start_array->allocate_block(p);
2299 }
2301 // Could update the promoted average here, but it is not typically updated at
2302 // full GCs and the value to use is unclear. Something like
2303 //
2304 // cur_promoted_avg + absorb_size / number_of_scavenges_since_last_full_gc.
2306 size_policy->set_bytes_absorbed_from_eden(absorb_size);
2307 return true;
2308 }
2310 GCTaskManager* const PSParallelCompact::gc_task_manager() {
2311 assert(ParallelScavengeHeap::gc_task_manager() != NULL,
2312 "shouldn't return NULL");
2313 return ParallelScavengeHeap::gc_task_manager();
2314 }
2316 void PSParallelCompact::marking_phase(ParCompactionManager* cm,
2317 bool maximum_heap_compaction) {
2318 // Recursively traverse all live objects and mark them
2319 TraceTime tm("marking phase", print_phases(), true, gclog_or_tty);
2321 ParallelScavengeHeap* heap = gc_heap();
2322 uint parallel_gc_threads = heap->gc_task_manager()->workers();
2323 uint active_gc_threads = heap->gc_task_manager()->active_workers();
2324 TaskQueueSetSuper* qset = ParCompactionManager::region_array();
2325 ParallelTaskTerminator terminator(active_gc_threads, qset);
2327 PSParallelCompact::MarkAndPushClosure mark_and_push_closure(cm);
2328 PSParallelCompact::FollowStackClosure follow_stack_closure(cm);
2330 // Need new claim bits before marking starts.
2331 ClassLoaderDataGraph::clear_claimed_marks();
2333 {
2334 TraceTime tm_m("par mark", print_phases(), true, gclog_or_tty);
2335 ParallelScavengeHeap::ParStrongRootsScope psrs;
2337 GCTaskQueue* q = GCTaskQueue::create();
2339 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::universe));
2340 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::jni_handles));
2341 // We scan the thread roots in parallel
2342 Threads::create_thread_roots_marking_tasks(q);
2343 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::object_synchronizer));
2344 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::flat_profiler));
2345 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::management));
2346 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::system_dictionary));
2347 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::jvmti));
2348 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::code_cache));
2350 if (active_gc_threads > 1) {
2351 for (uint j = 0; j < active_gc_threads; j++) {
2352 q->enqueue(new StealMarkingTask(&terminator));
2353 }
2354 }
2356 gc_task_manager()->execute_and_wait(q);
2357 }
2359 // Process reference objects found during marking
2360 {
2361 TraceTime tm_r("reference processing", print_phases(), true, gclog_or_tty);
2362 if (ref_processor()->processing_is_mt()) {
2363 RefProcTaskExecutor task_executor;
2364 ref_processor()->process_discovered_references(
2365 is_alive_closure(), &mark_and_push_closure, &follow_stack_closure,
2366 &task_executor);
2367 } else {
2368 ref_processor()->process_discovered_references(
2369 is_alive_closure(), &mark_and_push_closure, &follow_stack_closure, NULL);
2370 }
2371 }
2373 TraceTime tm_c("class unloading", print_phases(), true, gclog_or_tty);
2374 // Follow system dictionary roots and unload classes.
2375 bool purged_class = SystemDictionary::do_unloading(is_alive_closure());
2377 // Follow code cache roots.
2378 CodeCache::do_unloading(is_alive_closure(), &mark_and_push_closure,
2379 purged_class);
2380 cm->follow_marking_stacks(); // Flush marking stack.
2382 // Update subklass/sibling/implementor links of live klasses
2383 Klass::clean_weak_klass_links(is_alive_closure());
2385 // Visit interned string tables and delete unmarked oops
2386 StringTable::unlink(is_alive_closure());
2387 // Clean up unreferenced symbols in symbol table.
2388 SymbolTable::unlink();
2390 assert(cm->marking_stacks_empty(), "marking stacks should be empty");
2391 }
2393 void PSParallelCompact::follow_klass(ParCompactionManager* cm, Klass* klass) {
2394 ClassLoaderData* cld = klass->class_loader_data();
2395 assert(cld->has_defined(klass), "inconsistency!");
2397 // The actual processing of the klass is done when we
2398 // traverse the list of Klasses in the class loader data.
2399 PSParallelCompact::follow_class_loader(cm, cld);
2400 }
2402 void PSParallelCompact::adjust_klass(ParCompactionManager* cm, Klass* klass) {
2403 ClassLoaderData* cld = klass->class_loader_data();
2404 assert(cld->has_defined(klass), "inconsistency!");
2406 // The actual processing of the klass is done when we
2407 // traverse the list of Klasses in the class loader data.
2408 PSParallelCompact::adjust_class_loader(cm, cld);
2409 }
2411 void PSParallelCompact::follow_class_loader(ParCompactionManager* cm,
2412 ClassLoaderData* cld) {
2413 PSParallelCompact::MarkAndPushClosure mark_and_push_closure(cm);
2414 PSParallelCompact::FollowKlassClosure follow_klass_closure(&mark_and_push_closure);
2416 cld->oops_do(&mark_and_push_closure, &follow_klass_closure, true);
2417 }
2419 void PSParallelCompact::adjust_class_loader(ParCompactionManager* cm,
2420 ClassLoaderData* cld) {
2421 cld->oops_do(PSParallelCompact::adjust_root_pointer_closure(),
2422 PSParallelCompact::adjust_klass_closure(),
2423 true);
2424 }
2426 // This should be moved to the shared markSweep code!
2427 class PSAlwaysTrueClosure: public BoolObjectClosure {
2428 public:
2429 void do_object(oop p) { ShouldNotReachHere(); }
2430 bool do_object_b(oop p) { return true; }
2431 };
2432 static PSAlwaysTrueClosure always_true;
2434 void PSParallelCompact::adjust_roots() {
2435 // Adjust the pointers to reflect the new locations
2436 TraceTime tm("adjust roots", print_phases(), true, gclog_or_tty);
2438 // Need new claim bits when tracing through and adjusting pointers.
2439 ClassLoaderDataGraph::clear_claimed_marks();
2441 // General strong roots.
2442 Universe::oops_do(adjust_root_pointer_closure());
2443 JNIHandles::oops_do(adjust_root_pointer_closure()); // Global (strong) JNI handles
2444 Threads::oops_do(adjust_root_pointer_closure(), NULL);
2445 ObjectSynchronizer::oops_do(adjust_root_pointer_closure());
2446 FlatProfiler::oops_do(adjust_root_pointer_closure());
2447 Management::oops_do(adjust_root_pointer_closure());
2448 JvmtiExport::oops_do(adjust_root_pointer_closure());
2449 // SO_AllClasses
2450 SystemDictionary::oops_do(adjust_root_pointer_closure());
2451 ClassLoaderDataGraph::oops_do(adjust_root_pointer_closure(), adjust_klass_closure(), true);
2453 // Now adjust pointers in remaining weak roots. (All of which should
2454 // have been cleared if they pointed to non-surviving objects.)
2455 // Global (weak) JNI handles
2456 JNIHandles::weak_oops_do(&always_true, adjust_root_pointer_closure());
2458 CodeCache::oops_do(adjust_pointer_closure());
2459 StringTable::oops_do(adjust_root_pointer_closure());
2460 ref_processor()->weak_oops_do(adjust_root_pointer_closure());
2461 // Roots were visited so references into the young gen in roots
2462 // may have been scanned. Process them also.
2463 // Should the reference processor have a span that excludes
2464 // young gen objects?
2465 PSScavenge::reference_processor()->weak_oops_do(
2466 adjust_root_pointer_closure());
2467 }
2469 void PSParallelCompact::enqueue_region_draining_tasks(GCTaskQueue* q,
2470 uint parallel_gc_threads)
2471 {
2472 TraceTime tm("drain task setup", print_phases(), true, gclog_or_tty);
2474 // Find the threads that are active
2475 unsigned int which = 0;
2477 const uint task_count = MAX2(parallel_gc_threads, 1U);
2478 for (uint j = 0; j < task_count; j++) {
2479 q->enqueue(new DrainStacksCompactionTask(j));
2480 ParCompactionManager::verify_region_list_empty(j);
2481 // Set the region stacks variables to "no" region stack values
2482 // so that they will be recognized and needing a region stack
2483 // in the stealing tasks if they do not get one by executing
2484 // a draining stack.
2485 ParCompactionManager* cm = ParCompactionManager::manager_array(j);
2486 cm->set_region_stack(NULL);
2487 cm->set_region_stack_index((uint)max_uintx);
2488 }
2489 ParCompactionManager::reset_recycled_stack_index();
2491 // Find all regions that are available (can be filled immediately) and
2492 // distribute them to the thread stacks. The iteration is done in reverse
2493 // order (high to low) so the regions will be removed in ascending order.
2495 const ParallelCompactData& sd = PSParallelCompact::summary_data();
2497 size_t fillable_regions = 0; // A count for diagnostic purposes.
2498 // A region index which corresponds to the tasks created above.
2499 // "which" must be 0 <= which < task_count
2501 which = 0;
2502 // id + 1 is used to test termination so unsigned can
2503 // be used with an old_space_id == 0.
2504 for (unsigned int id = to_space_id; id + 1 > old_space_id; --id) {
2505 SpaceInfo* const space_info = _space_info + id;
2506 MutableSpace* const space = space_info->space();
2507 HeapWord* const new_top = space_info->new_top();
2509 const size_t beg_region = sd.addr_to_region_idx(space_info->dense_prefix());
2510 const size_t end_region =
2511 sd.addr_to_region_idx(sd.region_align_up(new_top));
2513 for (size_t cur = end_region - 1; cur + 1 > beg_region; --cur) {
2514 if (sd.region(cur)->claim_unsafe()) {
2515 ParCompactionManager::region_list_push(which, cur);
2517 if (TraceParallelOldGCCompactionPhase && Verbose) {
2518 const size_t count_mod_8 = fillable_regions & 7;
2519 if (count_mod_8 == 0) gclog_or_tty->print("fillable: ");
2520 gclog_or_tty->print(" " SIZE_FORMAT_W(7), cur);
2521 if (count_mod_8 == 7) gclog_or_tty->cr();
2522 }
2524 NOT_PRODUCT(++fillable_regions;)
2526 // Assign regions to tasks in round-robin fashion.
2527 if (++which == task_count) {
2528 assert(which <= parallel_gc_threads,
2529 "Inconsistent number of workers");
2530 which = 0;
2531 }
2532 }
2533 }
2534 }
2536 if (TraceParallelOldGCCompactionPhase) {
2537 if (Verbose && (fillable_regions & 7) != 0) gclog_or_tty->cr();
2538 gclog_or_tty->print_cr("%u initially fillable regions", fillable_regions);
2539 }
2540 }
2542 #define PAR_OLD_DENSE_PREFIX_OVER_PARTITIONING 4
2544 void PSParallelCompact::enqueue_dense_prefix_tasks(GCTaskQueue* q,
2545 uint parallel_gc_threads) {
2546 TraceTime tm("dense prefix task setup", print_phases(), true, gclog_or_tty);
2548 ParallelCompactData& sd = PSParallelCompact::summary_data();
2550 // Iterate over all the spaces adding tasks for updating
2551 // regions in the dense prefix. Assume that 1 gc thread
2552 // will work on opening the gaps and the remaining gc threads
2553 // will work on the dense prefix.
2554 unsigned int space_id;
2555 for (space_id = old_space_id; space_id < last_space_id; ++ space_id) {
2556 HeapWord* const dense_prefix_end = _space_info[space_id].dense_prefix();
2557 const MutableSpace* const space = _space_info[space_id].space();
2559 if (dense_prefix_end == space->bottom()) {
2560 // There is no dense prefix for this space.
2561 continue;
2562 }
2564 // The dense prefix is before this region.
2565 size_t region_index_end_dense_prefix =
2566 sd.addr_to_region_idx(dense_prefix_end);
2567 RegionData* const dense_prefix_cp =
2568 sd.region(region_index_end_dense_prefix);
2569 assert(dense_prefix_end == space->end() ||
2570 dense_prefix_cp->available() ||
2571 dense_prefix_cp->claimed(),
2572 "The region after the dense prefix should always be ready to fill");
2574 size_t region_index_start = sd.addr_to_region_idx(space->bottom());
2576 // Is there dense prefix work?
2577 size_t total_dense_prefix_regions =
2578 region_index_end_dense_prefix - region_index_start;
2579 // How many regions of the dense prefix should be given to
2580 // each thread?
2581 if (total_dense_prefix_regions > 0) {
2582 uint tasks_for_dense_prefix = 1;
2583 if (total_dense_prefix_regions <=
2584 (parallel_gc_threads * PAR_OLD_DENSE_PREFIX_OVER_PARTITIONING)) {
2585 // Don't over partition. This assumes that
2586 // PAR_OLD_DENSE_PREFIX_OVER_PARTITIONING is a small integer value
2587 // so there are not many regions to process.
2588 tasks_for_dense_prefix = parallel_gc_threads;
2589 } else {
2590 // Over partition
2591 tasks_for_dense_prefix = parallel_gc_threads *
2592 PAR_OLD_DENSE_PREFIX_OVER_PARTITIONING;
2593 }
2594 size_t regions_per_thread = total_dense_prefix_regions /
2595 tasks_for_dense_prefix;
2596 // Give each thread at least 1 region.
2597 if (regions_per_thread == 0) {
2598 regions_per_thread = 1;
2599 }
2601 for (uint k = 0; k < tasks_for_dense_prefix; k++) {
2602 if (region_index_start >= region_index_end_dense_prefix) {
2603 break;
2604 }
2605 // region_index_end is not processed
2606 size_t region_index_end = MIN2(region_index_start + regions_per_thread,
2607 region_index_end_dense_prefix);
2608 q->enqueue(new UpdateDensePrefixTask(SpaceId(space_id),
2609 region_index_start,
2610 region_index_end));
2611 region_index_start = region_index_end;
2612 }
2613 }
2614 // This gets any part of the dense prefix that did not
2615 // fit evenly.
2616 if (region_index_start < region_index_end_dense_prefix) {
2617 q->enqueue(new UpdateDensePrefixTask(SpaceId(space_id),
2618 region_index_start,
2619 region_index_end_dense_prefix));
2620 }
2621 }
2622 }
2624 void PSParallelCompact::enqueue_region_stealing_tasks(
2625 GCTaskQueue* q,
2626 ParallelTaskTerminator* terminator_ptr,
2627 uint parallel_gc_threads) {
2628 TraceTime tm("steal task setup", print_phases(), true, gclog_or_tty);
2630 // Once a thread has drained it's stack, it should try to steal regions from
2631 // other threads.
2632 if (parallel_gc_threads > 1) {
2633 for (uint j = 0; j < parallel_gc_threads; j++) {
2634 q->enqueue(new StealRegionCompactionTask(terminator_ptr));
2635 }
2636 }
2637 }
2639 void PSParallelCompact::compact() {
2640 // trace("5");
2641 TraceTime tm("compaction phase", print_phases(), true, gclog_or_tty);
2643 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
2644 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
2645 PSOldGen* old_gen = heap->old_gen();
2646 old_gen->start_array()->reset();
2647 uint parallel_gc_threads = heap->gc_task_manager()->workers();
2648 uint active_gc_threads = heap->gc_task_manager()->active_workers();
2649 TaskQueueSetSuper* qset = ParCompactionManager::region_array();
2650 ParallelTaskTerminator terminator(active_gc_threads, qset);
2652 GCTaskQueue* q = GCTaskQueue::create();
2653 enqueue_region_draining_tasks(q, active_gc_threads);
2654 enqueue_dense_prefix_tasks(q, active_gc_threads);
2655 enqueue_region_stealing_tasks(q, &terminator, active_gc_threads);
2657 {
2658 TraceTime tm_pc("par compact", print_phases(), true, gclog_or_tty);
2660 gc_task_manager()->execute_and_wait(q);
2662 #ifdef ASSERT
2663 // Verify that all regions have been processed before the deferred updates.
2664 for (unsigned int id = old_space_id; id < last_space_id; ++id) {
2665 verify_complete(SpaceId(id));
2666 }
2667 #endif
2668 }
2670 {
2671 // Update the deferred objects, if any. Any compaction manager can be used.
2672 TraceTime tm_du("deferred updates", print_phases(), true, gclog_or_tty);
2673 ParCompactionManager* cm = ParCompactionManager::manager_array(0);
2674 for (unsigned int id = old_space_id; id < last_space_id; ++id) {
2675 update_deferred_objects(cm, SpaceId(id));
2676 }
2677 }
2678 }
2680 #ifdef ASSERT
2681 void PSParallelCompact::verify_complete(SpaceId space_id) {
2682 // All Regions between space bottom() to new_top() should be marked as filled
2683 // and all Regions between new_top() and top() should be available (i.e.,
2684 // should have been emptied).
2685 ParallelCompactData& sd = summary_data();
2686 SpaceInfo si = _space_info[space_id];
2687 HeapWord* new_top_addr = sd.region_align_up(si.new_top());
2688 HeapWord* old_top_addr = sd.region_align_up(si.space()->top());
2689 const size_t beg_region = sd.addr_to_region_idx(si.space()->bottom());
2690 const size_t new_top_region = sd.addr_to_region_idx(new_top_addr);
2691 const size_t old_top_region = sd.addr_to_region_idx(old_top_addr);
2693 bool issued_a_warning = false;
2695 size_t cur_region;
2696 for (cur_region = beg_region; cur_region < new_top_region; ++cur_region) {
2697 const RegionData* const c = sd.region(cur_region);
2698 if (!c->completed()) {
2699 warning("region " SIZE_FORMAT " not filled: "
2700 "destination_count=" SIZE_FORMAT,
2701 cur_region, c->destination_count());
2702 issued_a_warning = true;
2703 }
2704 }
2706 for (cur_region = new_top_region; cur_region < old_top_region; ++cur_region) {
2707 const RegionData* const c = sd.region(cur_region);
2708 if (!c->available()) {
2709 warning("region " SIZE_FORMAT " not empty: "
2710 "destination_count=" SIZE_FORMAT,
2711 cur_region, c->destination_count());
2712 issued_a_warning = true;
2713 }
2714 }
2716 if (issued_a_warning) {
2717 print_region_ranges();
2718 }
2719 }
2720 #endif // #ifdef ASSERT
2723 #ifdef VALIDATE_MARK_SWEEP
2725 void PSParallelCompact::track_adjusted_pointer(void* p, bool isroot) {
2726 if (!ValidateMarkSweep)
2727 return;
2729 if (!isroot) {
2730 if (_pointer_tracking) {
2731 guarantee(_adjusted_pointers->contains(p), "should have seen this pointer");
2732 _adjusted_pointers->remove(p);
2733 }
2734 } else {
2735 ptrdiff_t index = _root_refs_stack->find(p);
2736 if (index != -1) {
2737 int l = _root_refs_stack->length();
2738 if (l > 0 && l - 1 != index) {
2739 void* last = _root_refs_stack->pop();
2740 assert(last != p, "should be different");
2741 _root_refs_stack->at_put(index, last);
2742 } else {
2743 _root_refs_stack->remove(p);
2744 }
2745 }
2746 }
2747 }
2750 void PSParallelCompact::check_adjust_pointer(void* p) {
2751 _adjusted_pointers->push(p);
2752 }
2755 class AdjusterTracker: public OopClosure {
2756 public:
2757 AdjusterTracker() {};
2758 void do_oop(oop* o) { PSParallelCompact::check_adjust_pointer(o); }
2759 void do_oop(narrowOop* o) { PSParallelCompact::check_adjust_pointer(o); }
2760 };
2763 void PSParallelCompact::track_interior_pointers(oop obj) {
2764 if (ValidateMarkSweep) {
2765 _adjusted_pointers->clear();
2766 _pointer_tracking = true;
2768 AdjusterTracker checker;
2769 obj->oop_iterate_no_header(&checker);
2770 }
2771 }
2774 void PSParallelCompact::check_interior_pointers() {
2775 if (ValidateMarkSweep) {
2776 _pointer_tracking = false;
2777 guarantee(_adjusted_pointers->length() == 0, "should have processed the same pointers");
2778 }
2779 }
2782 void PSParallelCompact::reset_live_oop_tracking() {
2783 if (ValidateMarkSweep) {
2784 guarantee((size_t)_live_oops->length() == _live_oops_index, "should be at end of live oops");
2785 _live_oops_index = 0;
2786 }
2787 }
2790 void PSParallelCompact::register_live_oop(oop p, size_t size) {
2791 if (ValidateMarkSweep) {
2792 _live_oops->push(p);
2793 _live_oops_size->push(size);
2794 _live_oops_index++;
2795 }
2796 }
2798 void PSParallelCompact::validate_live_oop(oop p, size_t size) {
2799 if (ValidateMarkSweep) {
2800 oop obj = _live_oops->at((int)_live_oops_index);
2801 guarantee(obj == p, "should be the same object");
2802 guarantee(_live_oops_size->at((int)_live_oops_index) == size, "should be the same size");
2803 _live_oops_index++;
2804 }
2805 }
2807 void PSParallelCompact::live_oop_moved_to(HeapWord* q, size_t size,
2808 HeapWord* compaction_top) {
2809 assert(oop(q)->forwardee() == NULL || oop(q)->forwardee() == oop(compaction_top),
2810 "should be moved to forwarded location");
2811 if (ValidateMarkSweep) {
2812 PSParallelCompact::validate_live_oop(oop(q), size);
2813 _live_oops_moved_to->push(oop(compaction_top));
2814 }
2815 if (RecordMarkSweepCompaction) {
2816 _cur_gc_live_oops->push(q);
2817 _cur_gc_live_oops_moved_to->push(compaction_top);
2818 _cur_gc_live_oops_size->push(size);
2819 }
2820 }
2823 void PSParallelCompact::compaction_complete() {
2824 if (RecordMarkSweepCompaction) {
2825 GrowableArray<HeapWord*>* _tmp_live_oops = _cur_gc_live_oops;
2826 GrowableArray<HeapWord*>* _tmp_live_oops_moved_to = _cur_gc_live_oops_moved_to;
2827 GrowableArray<size_t> * _tmp_live_oops_size = _cur_gc_live_oops_size;
2829 _cur_gc_live_oops = _last_gc_live_oops;
2830 _cur_gc_live_oops_moved_to = _last_gc_live_oops_moved_to;
2831 _cur_gc_live_oops_size = _last_gc_live_oops_size;
2832 _last_gc_live_oops = _tmp_live_oops;
2833 _last_gc_live_oops_moved_to = _tmp_live_oops_moved_to;
2834 _last_gc_live_oops_size = _tmp_live_oops_size;
2835 }
2836 }
2839 void PSParallelCompact::print_new_location_of_heap_address(HeapWord* q) {
2840 if (!RecordMarkSweepCompaction) {
2841 tty->print_cr("Requires RecordMarkSweepCompaction to be enabled");
2842 return;
2843 }
2845 if (_last_gc_live_oops == NULL) {
2846 tty->print_cr("No compaction information gathered yet");
2847 return;
2848 }
2850 for (int i = 0; i < _last_gc_live_oops->length(); i++) {
2851 HeapWord* old_oop = _last_gc_live_oops->at(i);
2852 size_t sz = _last_gc_live_oops_size->at(i);
2853 if (old_oop <= q && q < (old_oop + sz)) {
2854 HeapWord* new_oop = _last_gc_live_oops_moved_to->at(i);
2855 size_t offset = (q - old_oop);
2856 tty->print_cr("Address " PTR_FORMAT, q);
2857 tty->print_cr(" Was in oop " PTR_FORMAT ", size %d, at offset %d", old_oop, sz, offset);
2858 tty->print_cr(" Now in oop " PTR_FORMAT ", actual address " PTR_FORMAT, new_oop, new_oop + offset);
2859 return;
2860 }
2861 }
2863 tty->print_cr("Address " PTR_FORMAT " not found in live oop information from last GC", q);
2864 }
2865 #endif //VALIDATE_MARK_SWEEP
2867 // Update interior oops in the ranges of regions [beg_region, end_region).
2868 void
2869 PSParallelCompact::update_and_deadwood_in_dense_prefix(ParCompactionManager* cm,
2870 SpaceId space_id,
2871 size_t beg_region,
2872 size_t end_region) {
2873 ParallelCompactData& sd = summary_data();
2874 ParMarkBitMap* const mbm = mark_bitmap();
2876 HeapWord* beg_addr = sd.region_to_addr(beg_region);
2877 HeapWord* const end_addr = sd.region_to_addr(end_region);
2878 assert(beg_region <= end_region, "bad region range");
2879 assert(end_addr <= dense_prefix(space_id), "not in the dense prefix");
2881 #ifdef ASSERT
2882 // Claim the regions to avoid triggering an assert when they are marked as
2883 // filled.
2884 for (size_t claim_region = beg_region; claim_region < end_region; ++claim_region) {
2885 assert(sd.region(claim_region)->claim_unsafe(), "claim() failed");
2886 }
2887 #endif // #ifdef ASSERT
2889 if (beg_addr != space(space_id)->bottom()) {
2890 // Find the first live object or block of dead space that *starts* in this
2891 // range of regions. If a partial object crosses onto the region, skip it;
2892 // it will be marked for 'deferred update' when the object head is
2893 // processed. If dead space crosses onto the region, it is also skipped; it
2894 // will be filled when the prior region is processed. If neither of those
2895 // apply, the first word in the region is the start of a live object or dead
2896 // space.
2897 assert(beg_addr > space(space_id)->bottom(), "sanity");
2898 const RegionData* const cp = sd.region(beg_region);
2899 if (cp->partial_obj_size() != 0) {
2900 beg_addr = sd.partial_obj_end(beg_region);
2901 } else if (dead_space_crosses_boundary(cp, mbm->addr_to_bit(beg_addr))) {
2902 beg_addr = mbm->find_obj_beg(beg_addr, end_addr);
2903 }
2904 }
2906 if (beg_addr < end_addr) {
2907 // A live object or block of dead space starts in this range of Regions.
2908 HeapWord* const dense_prefix_end = dense_prefix(space_id);
2910 // Create closures and iterate.
2911 UpdateOnlyClosure update_closure(mbm, cm, space_id);
2912 FillClosure fill_closure(cm, space_id);
2913 ParMarkBitMap::IterationStatus status;
2914 status = mbm->iterate(&update_closure, &fill_closure, beg_addr, end_addr,
2915 dense_prefix_end);
2916 if (status == ParMarkBitMap::incomplete) {
2917 update_closure.do_addr(update_closure.source());
2918 }
2919 }
2921 // Mark the regions as filled.
2922 RegionData* const beg_cp = sd.region(beg_region);
2923 RegionData* const end_cp = sd.region(end_region);
2924 for (RegionData* cp = beg_cp; cp < end_cp; ++cp) {
2925 cp->set_completed();
2926 }
2927 }
2929 // Return the SpaceId for the space containing addr. If addr is not in the
2930 // heap, last_space_id is returned. In debug mode it expects the address to be
2931 // in the heap and asserts such.
2932 PSParallelCompact::SpaceId PSParallelCompact::space_id(HeapWord* addr) {
2933 assert(Universe::heap()->is_in_reserved(addr), "addr not in the heap");
2935 for (unsigned int id = old_space_id; id < last_space_id; ++id) {
2936 if (_space_info[id].space()->contains(addr)) {
2937 return SpaceId(id);
2938 }
2939 }
2941 assert(false, "no space contains the addr");
2942 return last_space_id;
2943 }
2945 void PSParallelCompact::update_deferred_objects(ParCompactionManager* cm,
2946 SpaceId id) {
2947 assert(id < last_space_id, "bad space id");
2949 ParallelCompactData& sd = summary_data();
2950 const SpaceInfo* const space_info = _space_info + id;
2951 ObjectStartArray* const start_array = space_info->start_array();
2953 const MutableSpace* const space = space_info->space();
2954 assert(space_info->dense_prefix() >= space->bottom(), "dense_prefix not set");
2955 HeapWord* const beg_addr = space_info->dense_prefix();
2956 HeapWord* const end_addr = sd.region_align_up(space_info->new_top());
2958 const RegionData* const beg_region = sd.addr_to_region_ptr(beg_addr);
2959 const RegionData* const end_region = sd.addr_to_region_ptr(end_addr);
2960 const RegionData* cur_region;
2961 for (cur_region = beg_region; cur_region < end_region; ++cur_region) {
2962 HeapWord* const addr = cur_region->deferred_obj_addr();
2963 if (addr != NULL) {
2964 if (start_array != NULL) {
2965 start_array->allocate_block(addr);
2966 }
2967 oop(addr)->update_contents(cm);
2968 assert(oop(addr)->is_oop_or_null(), "should be an oop now");
2969 }
2970 }
2971 }
2973 // Skip over count live words starting from beg, and return the address of the
2974 // next live word. Unless marked, the word corresponding to beg is assumed to
2975 // be dead. Callers must either ensure beg does not correspond to the middle of
2976 // an object, or account for those live words in some other way. Callers must
2977 // also ensure that there are enough live words in the range [beg, end) to skip.
2978 HeapWord*
2979 PSParallelCompact::skip_live_words(HeapWord* beg, HeapWord* end, size_t count)
2980 {
2981 assert(count > 0, "sanity");
2983 ParMarkBitMap* m = mark_bitmap();
2984 idx_t bits_to_skip = m->words_to_bits(count);
2985 idx_t cur_beg = m->addr_to_bit(beg);
2986 const idx_t search_end = BitMap::word_align_up(m->addr_to_bit(end));
2988 do {
2989 cur_beg = m->find_obj_beg(cur_beg, search_end);
2990 idx_t cur_end = m->find_obj_end(cur_beg, search_end);
2991 const size_t obj_bits = cur_end - cur_beg + 1;
2992 if (obj_bits > bits_to_skip) {
2993 return m->bit_to_addr(cur_beg + bits_to_skip);
2994 }
2995 bits_to_skip -= obj_bits;
2996 cur_beg = cur_end + 1;
2997 } while (bits_to_skip > 0);
2999 // Skipping the desired number of words landed just past the end of an object.
3000 // Find the start of the next object.
3001 cur_beg = m->find_obj_beg(cur_beg, search_end);
3002 assert(cur_beg < m->addr_to_bit(end), "not enough live words to skip");
3003 return m->bit_to_addr(cur_beg);
3004 }
3006 HeapWord* PSParallelCompact::first_src_addr(HeapWord* const dest_addr,
3007 SpaceId src_space_id,
3008 size_t src_region_idx)
3009 {
3010 assert(summary_data().is_region_aligned(dest_addr), "not aligned");
3012 const SplitInfo& split_info = _space_info[src_space_id].split_info();
3013 if (split_info.dest_region_addr() == dest_addr) {
3014 // The partial object ending at the split point contains the first word to
3015 // be copied to dest_addr.
3016 return split_info.first_src_addr();
3017 }
3019 const ParallelCompactData& sd = summary_data();
3020 ParMarkBitMap* const bitmap = mark_bitmap();
3021 const size_t RegionSize = ParallelCompactData::RegionSize;
3023 assert(sd.is_region_aligned(dest_addr), "not aligned");
3024 const RegionData* const src_region_ptr = sd.region(src_region_idx);
3025 const size_t partial_obj_size = src_region_ptr->partial_obj_size();
3026 HeapWord* const src_region_destination = src_region_ptr->destination();
3028 assert(dest_addr >= src_region_destination, "wrong src region");
3029 assert(src_region_ptr->data_size() > 0, "src region cannot be empty");
3031 HeapWord* const src_region_beg = sd.region_to_addr(src_region_idx);
3032 HeapWord* const src_region_end = src_region_beg + RegionSize;
3034 HeapWord* addr = src_region_beg;
3035 if (dest_addr == src_region_destination) {
3036 // Return the first live word in the source region.
3037 if (partial_obj_size == 0) {
3038 addr = bitmap->find_obj_beg(addr, src_region_end);
3039 assert(addr < src_region_end, "no objects start in src region");
3040 }
3041 return addr;
3042 }
3044 // Must skip some live data.
3045 size_t words_to_skip = dest_addr - src_region_destination;
3046 assert(src_region_ptr->data_size() > words_to_skip, "wrong src region");
3048 if (partial_obj_size >= words_to_skip) {
3049 // All the live words to skip are part of the partial object.
3050 addr += words_to_skip;
3051 if (partial_obj_size == words_to_skip) {
3052 // Find the first live word past the partial object.
3053 addr = bitmap->find_obj_beg(addr, src_region_end);
3054 assert(addr < src_region_end, "wrong src region");
3055 }
3056 return addr;
3057 }
3059 // Skip over the partial object (if any).
3060 if (partial_obj_size != 0) {
3061 words_to_skip -= partial_obj_size;
3062 addr += partial_obj_size;
3063 }
3065 // Skip over live words due to objects that start in the region.
3066 addr = skip_live_words(addr, src_region_end, words_to_skip);
3067 assert(addr < src_region_end, "wrong src region");
3068 return addr;
3069 }
3071 void PSParallelCompact::decrement_destination_counts(ParCompactionManager* cm,
3072 SpaceId src_space_id,
3073 size_t beg_region,
3074 HeapWord* end_addr)
3075 {
3076 ParallelCompactData& sd = summary_data();
3078 #ifdef ASSERT
3079 MutableSpace* const src_space = _space_info[src_space_id].space();
3080 HeapWord* const beg_addr = sd.region_to_addr(beg_region);
3081 assert(src_space->contains(beg_addr) || beg_addr == src_space->end(),
3082 "src_space_id does not match beg_addr");
3083 assert(src_space->contains(end_addr) || end_addr == src_space->end(),
3084 "src_space_id does not match end_addr");
3085 #endif // #ifdef ASSERT
3087 RegionData* const beg = sd.region(beg_region);
3088 RegionData* const end = sd.addr_to_region_ptr(sd.region_align_up(end_addr));
3090 // Regions up to new_top() are enqueued if they become available.
3091 HeapWord* const new_top = _space_info[src_space_id].new_top();
3092 RegionData* const enqueue_end =
3093 sd.addr_to_region_ptr(sd.region_align_up(new_top));
3095 for (RegionData* cur = beg; cur < end; ++cur) {
3096 assert(cur->data_size() > 0, "region must have live data");
3097 cur->decrement_destination_count();
3098 if (cur < enqueue_end && cur->available() && cur->claim()) {
3099 cm->push_region(sd.region(cur));
3100 }
3101 }
3102 }
3104 size_t PSParallelCompact::next_src_region(MoveAndUpdateClosure& closure,
3105 SpaceId& src_space_id,
3106 HeapWord*& src_space_top,
3107 HeapWord* end_addr)
3108 {
3109 typedef ParallelCompactData::RegionData RegionData;
3111 ParallelCompactData& sd = PSParallelCompact::summary_data();
3112 const size_t region_size = ParallelCompactData::RegionSize;
3114 size_t src_region_idx = 0;
3116 // Skip empty regions (if any) up to the top of the space.
3117 HeapWord* const src_aligned_up = sd.region_align_up(end_addr);
3118 RegionData* src_region_ptr = sd.addr_to_region_ptr(src_aligned_up);
3119 HeapWord* const top_aligned_up = sd.region_align_up(src_space_top);
3120 const RegionData* const top_region_ptr =
3121 sd.addr_to_region_ptr(top_aligned_up);
3122 while (src_region_ptr < top_region_ptr && src_region_ptr->data_size() == 0) {
3123 ++src_region_ptr;
3124 }
3126 if (src_region_ptr < top_region_ptr) {
3127 // The next source region is in the current space. Update src_region_idx
3128 // and the source address to match src_region_ptr.
3129 src_region_idx = sd.region(src_region_ptr);
3130 HeapWord* const src_region_addr = sd.region_to_addr(src_region_idx);
3131 if (src_region_addr > closure.source()) {
3132 closure.set_source(src_region_addr);
3133 }
3134 return src_region_idx;
3135 }
3137 // Switch to a new source space and find the first non-empty region.
3138 unsigned int space_id = src_space_id + 1;
3139 assert(space_id < last_space_id, "not enough spaces");
3141 HeapWord* const destination = closure.destination();
3143 do {
3144 MutableSpace* space = _space_info[space_id].space();
3145 HeapWord* const bottom = space->bottom();
3146 const RegionData* const bottom_cp = sd.addr_to_region_ptr(bottom);
3148 // Iterate over the spaces that do not compact into themselves.
3149 if (bottom_cp->destination() != bottom) {
3150 HeapWord* const top_aligned_up = sd.region_align_up(space->top());
3151 const RegionData* const top_cp = sd.addr_to_region_ptr(top_aligned_up);
3153 for (const RegionData* src_cp = bottom_cp; src_cp < top_cp; ++src_cp) {
3154 if (src_cp->live_obj_size() > 0) {
3155 // Found it.
3156 assert(src_cp->destination() == destination,
3157 "first live obj in the space must match the destination");
3158 assert(src_cp->partial_obj_size() == 0,
3159 "a space cannot begin with a partial obj");
3161 src_space_id = SpaceId(space_id);
3162 src_space_top = space->top();
3163 const size_t src_region_idx = sd.region(src_cp);
3164 closure.set_source(sd.region_to_addr(src_region_idx));
3165 return src_region_idx;
3166 } else {
3167 assert(src_cp->data_size() == 0, "sanity");
3168 }
3169 }
3170 }
3171 } while (++space_id < last_space_id);
3173 assert(false, "no source region was found");
3174 return 0;
3175 }
3177 void PSParallelCompact::fill_region(ParCompactionManager* cm, size_t region_idx)
3178 {
3179 typedef ParMarkBitMap::IterationStatus IterationStatus;
3180 const size_t RegionSize = ParallelCompactData::RegionSize;
3181 ParMarkBitMap* const bitmap = mark_bitmap();
3182 ParallelCompactData& sd = summary_data();
3183 RegionData* const region_ptr = sd.region(region_idx);
3185 // Get the items needed to construct the closure.
3186 HeapWord* dest_addr = sd.region_to_addr(region_idx);
3187 SpaceId dest_space_id = space_id(dest_addr);
3188 ObjectStartArray* start_array = _space_info[dest_space_id].start_array();
3189 HeapWord* new_top = _space_info[dest_space_id].new_top();
3190 assert(dest_addr < new_top, "sanity");
3191 const size_t words = MIN2(pointer_delta(new_top, dest_addr), RegionSize);
3193 // Get the source region and related info.
3194 size_t src_region_idx = region_ptr->source_region();
3195 SpaceId src_space_id = space_id(sd.region_to_addr(src_region_idx));
3196 HeapWord* src_space_top = _space_info[src_space_id].space()->top();
3198 MoveAndUpdateClosure closure(bitmap, cm, start_array, dest_addr, words);
3199 closure.set_source(first_src_addr(dest_addr, src_space_id, src_region_idx));
3201 // Adjust src_region_idx to prepare for decrementing destination counts (the
3202 // destination count is not decremented when a region is copied to itself).
3203 if (src_region_idx == region_idx) {
3204 src_region_idx += 1;
3205 }
3207 if (bitmap->is_unmarked(closure.source())) {
3208 // The first source word is in the middle of an object; copy the remainder
3209 // of the object or as much as will fit. The fact that pointer updates were
3210 // deferred will be noted when the object header is processed.
3211 HeapWord* const old_src_addr = closure.source();
3212 closure.copy_partial_obj();
3213 if (closure.is_full()) {
3214 decrement_destination_counts(cm, src_space_id, src_region_idx,
3215 closure.source());
3216 region_ptr->set_deferred_obj_addr(NULL);
3217 region_ptr->set_completed();
3218 return;
3219 }
3221 HeapWord* const end_addr = sd.region_align_down(closure.source());
3222 if (sd.region_align_down(old_src_addr) != end_addr) {
3223 // The partial object was copied from more than one source region.
3224 decrement_destination_counts(cm, src_space_id, src_region_idx, end_addr);
3226 // Move to the next source region, possibly switching spaces as well. All
3227 // args except end_addr may be modified.
3228 src_region_idx = next_src_region(closure, src_space_id, src_space_top,
3229 end_addr);
3230 }
3231 }
3233 do {
3234 HeapWord* const cur_addr = closure.source();
3235 HeapWord* const end_addr = MIN2(sd.region_align_up(cur_addr + 1),
3236 src_space_top);
3237 IterationStatus status = bitmap->iterate(&closure, cur_addr, end_addr);
3239 if (status == ParMarkBitMap::incomplete) {
3240 // The last obj that starts in the source region does not end in the
3241 // region.
3242 assert(closure.source() < end_addr, "sanity");
3243 HeapWord* const obj_beg = closure.source();
3244 HeapWord* const range_end = MIN2(obj_beg + closure.words_remaining(),
3245 src_space_top);
3246 HeapWord* const obj_end = bitmap->find_obj_end(obj_beg, range_end);
3247 if (obj_end < range_end) {
3248 // The end was found; the entire object will fit.
3249 status = closure.do_addr(obj_beg, bitmap->obj_size(obj_beg, obj_end));
3250 assert(status != ParMarkBitMap::would_overflow, "sanity");
3251 } else {
3252 // The end was not found; the object will not fit.
3253 assert(range_end < src_space_top, "obj cannot cross space boundary");
3254 status = ParMarkBitMap::would_overflow;
3255 }
3256 }
3258 if (status == ParMarkBitMap::would_overflow) {
3259 // The last object did not fit. Note that interior oop updates were
3260 // deferred, then copy enough of the object to fill the region.
3261 region_ptr->set_deferred_obj_addr(closure.destination());
3262 status = closure.copy_until_full(); // copies from closure.source()
3264 decrement_destination_counts(cm, src_space_id, src_region_idx,
3265 closure.source());
3266 region_ptr->set_completed();
3267 return;
3268 }
3270 if (status == ParMarkBitMap::full) {
3271 decrement_destination_counts(cm, src_space_id, src_region_idx,
3272 closure.source());
3273 region_ptr->set_deferred_obj_addr(NULL);
3274 region_ptr->set_completed();
3275 return;
3276 }
3278 decrement_destination_counts(cm, src_space_id, src_region_idx, end_addr);
3280 // Move to the next source region, possibly switching spaces as well. All
3281 // args except end_addr may be modified.
3282 src_region_idx = next_src_region(closure, src_space_id, src_space_top,
3283 end_addr);
3284 } while (true);
3285 }
3287 void
3288 PSParallelCompact::move_and_update(ParCompactionManager* cm, SpaceId space_id) {
3289 const MutableSpace* sp = space(space_id);
3290 if (sp->is_empty()) {
3291 return;
3292 }
3294 ParallelCompactData& sd = PSParallelCompact::summary_data();
3295 ParMarkBitMap* const bitmap = mark_bitmap();
3296 HeapWord* const dp_addr = dense_prefix(space_id);
3297 HeapWord* beg_addr = sp->bottom();
3298 HeapWord* end_addr = sp->top();
3300 assert(beg_addr <= dp_addr && dp_addr <= end_addr, "bad dense prefix");
3302 const size_t beg_region = sd.addr_to_region_idx(beg_addr);
3303 const size_t dp_region = sd.addr_to_region_idx(dp_addr);
3304 if (beg_region < dp_region) {
3305 update_and_deadwood_in_dense_prefix(cm, space_id, beg_region, dp_region);
3306 }
3308 // The destination of the first live object that starts in the region is one
3309 // past the end of the partial object entering the region (if any).
3310 HeapWord* const dest_addr = sd.partial_obj_end(dp_region);
3311 HeapWord* const new_top = _space_info[space_id].new_top();
3312 assert(new_top >= dest_addr, "bad new_top value");
3313 const size_t words = pointer_delta(new_top, dest_addr);
3315 if (words > 0) {
3316 ObjectStartArray* start_array = _space_info[space_id].start_array();
3317 MoveAndUpdateClosure closure(bitmap, cm, start_array, dest_addr, words);
3319 ParMarkBitMap::IterationStatus status;
3320 status = bitmap->iterate(&closure, dest_addr, end_addr);
3321 assert(status == ParMarkBitMap::full, "iteration not complete");
3322 assert(bitmap->find_obj_beg(closure.source(), end_addr) == end_addr,
3323 "live objects skipped because closure is full");
3324 }
3325 }
3327 jlong PSParallelCompact::millis_since_last_gc() {
3328 // We need a monotonically non-deccreasing time in ms but
3329 // os::javaTimeMillis() does not guarantee monotonicity.
3330 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
3331 jlong ret_val = now - _time_of_last_gc;
3332 // XXX See note in genCollectedHeap::millis_since_last_gc().
3333 if (ret_val < 0) {
3334 NOT_PRODUCT(warning("time warp: "INT64_FORMAT, ret_val);)
3335 return 0;
3336 }
3337 return ret_val;
3338 }
3340 void PSParallelCompact::reset_millis_since_last_gc() {
3341 // We need a monotonically non-deccreasing time in ms but
3342 // os::javaTimeMillis() does not guarantee monotonicity.
3343 _time_of_last_gc = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
3344 }
3346 ParMarkBitMap::IterationStatus MoveAndUpdateClosure::copy_until_full()
3347 {
3348 if (source() != destination()) {
3349 DEBUG_ONLY(PSParallelCompact::check_new_location(source(), destination());)
3350 Copy::aligned_conjoint_words(source(), destination(), words_remaining());
3351 }
3352 update_state(words_remaining());
3353 assert(is_full(), "sanity");
3354 return ParMarkBitMap::full;
3355 }
3357 void MoveAndUpdateClosure::copy_partial_obj()
3358 {
3359 size_t words = words_remaining();
3361 HeapWord* const range_end = MIN2(source() + words, bitmap()->region_end());
3362 HeapWord* const end_addr = bitmap()->find_obj_end(source(), range_end);
3363 if (end_addr < range_end) {
3364 words = bitmap()->obj_size(source(), end_addr);
3365 }
3367 // This test is necessary; if omitted, the pointer updates to a partial object
3368 // that crosses the dense prefix boundary could be overwritten.
3369 if (source() != destination()) {
3370 DEBUG_ONLY(PSParallelCompact::check_new_location(source(), destination());)
3371 Copy::aligned_conjoint_words(source(), destination(), words);
3372 }
3373 update_state(words);
3374 }
3376 ParMarkBitMapClosure::IterationStatus
3377 MoveAndUpdateClosure::do_addr(HeapWord* addr, size_t words) {
3378 assert(destination() != NULL, "sanity");
3379 assert(bitmap()->obj_size(addr) == words, "bad size");
3381 _source = addr;
3382 assert(PSParallelCompact::summary_data().calc_new_pointer(source()) ==
3383 destination(), "wrong destination");
3385 if (words > words_remaining()) {
3386 return ParMarkBitMap::would_overflow;
3387 }
3389 // The start_array must be updated even if the object is not moving.
3390 if (_start_array != NULL) {
3391 _start_array->allocate_block(destination());
3392 }
3394 if (destination() != source()) {
3395 DEBUG_ONLY(PSParallelCompact::check_new_location(source(), destination());)
3396 Copy::aligned_conjoint_words(source(), destination(), words);
3397 }
3399 oop moved_oop = (oop) destination();
3400 moved_oop->update_contents(compaction_manager());
3401 assert(moved_oop->is_oop_or_null(), "Object should be whole at this point");
3403 update_state(words);
3404 assert(destination() == (HeapWord*)moved_oop + moved_oop->size(), "sanity");
3405 return is_full() ? ParMarkBitMap::full : ParMarkBitMap::incomplete;
3406 }
3408 UpdateOnlyClosure::UpdateOnlyClosure(ParMarkBitMap* mbm,
3409 ParCompactionManager* cm,
3410 PSParallelCompact::SpaceId space_id) :
3411 ParMarkBitMapClosure(mbm, cm),
3412 _space_id(space_id),
3413 _start_array(PSParallelCompact::start_array(space_id))
3414 {
3415 }
3417 // Updates the references in the object to their new values.
3418 ParMarkBitMapClosure::IterationStatus
3419 UpdateOnlyClosure::do_addr(HeapWord* addr, size_t words) {
3420 do_addr(addr);
3421 return ParMarkBitMap::incomplete;
3422 }