1 /*
2 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "incls/_precompiled.incl"
26 #include "incls/_psParallelCompact.cpp.incl"
27
28 #include <math.h>
29
30 // All sizes are in HeapWords.
31 const size_t ParallelCompactData::Log2RegionSize = 9; // 512 words
32 const size_t ParallelCompactData::RegionSize = (size_t)1 << Log2RegionSize;
33 const size_t ParallelCompactData::RegionSizeBytes =
34 RegionSize << LogHeapWordSize;
35 const size_t ParallelCompactData::RegionSizeOffsetMask = RegionSize - 1;
36 const size_t ParallelCompactData::RegionAddrOffsetMask = RegionSizeBytes - 1;
37 const size_t ParallelCompactData::RegionAddrMask = ~RegionAddrOffsetMask;
38
39 const ParallelCompactData::RegionData::region_sz_t
40 ParallelCompactData::RegionData::dc_shift = 27;
41
42 const ParallelCompactData::RegionData::region_sz_t
43 ParallelCompactData::RegionData::dc_mask = ~0U << dc_shift;
44
45 const ParallelCompactData::RegionData::region_sz_t
46 ParallelCompactData::RegionData::dc_one = 0x1U << dc_shift;
47
48 const ParallelCompactData::RegionData::region_sz_t
49 ParallelCompactData::RegionData::los_mask = ~dc_mask;
50
51 const ParallelCompactData::RegionData::region_sz_t
52 ParallelCompactData::RegionData::dc_claimed = 0x8U << dc_shift;
53
54 const ParallelCompactData::RegionData::region_sz_t
55 ParallelCompactData::RegionData::dc_completed = 0xcU << dc_shift;
56
57 SpaceInfo PSParallelCompact::_space_info[PSParallelCompact::last_space_id];
58 bool PSParallelCompact::_print_phases = false;
59
60 ReferenceProcessor* PSParallelCompact::_ref_processor = NULL;
61 klassOop PSParallelCompact::_updated_int_array_klass_obj = NULL;
62
63 double PSParallelCompact::_dwl_mean;
64 double PSParallelCompact::_dwl_std_dev;
65 double PSParallelCompact::_dwl_first_term;
66 double PSParallelCompact::_dwl_adjustment;
67 #ifdef ASSERT
68 bool PSParallelCompact::_dwl_initialized = false;
69 #endif // #ifdef ASSERT
70
71 #ifdef VALIDATE_MARK_SWEEP
72 GrowableArray<void*>* PSParallelCompact::_root_refs_stack = NULL;
73 GrowableArray<oop> * PSParallelCompact::_live_oops = NULL;
74 GrowableArray<oop> * PSParallelCompact::_live_oops_moved_to = NULL;
75 GrowableArray<size_t>* PSParallelCompact::_live_oops_size = NULL;
76 size_t PSParallelCompact::_live_oops_index = 0;
77 size_t PSParallelCompact::_live_oops_index_at_perm = 0;
78 GrowableArray<void*>* PSParallelCompact::_other_refs_stack = NULL;
79 GrowableArray<void*>* PSParallelCompact::_adjusted_pointers = NULL;
80 bool PSParallelCompact::_pointer_tracking = false;
81 bool PSParallelCompact::_root_tracking = true;
82
83 GrowableArray<HeapWord*>* PSParallelCompact::_cur_gc_live_oops = NULL;
84 GrowableArray<HeapWord*>* PSParallelCompact::_cur_gc_live_oops_moved_to = NULL;
85 GrowableArray<size_t> * PSParallelCompact::_cur_gc_live_oops_size = NULL;
86 GrowableArray<HeapWord*>* PSParallelCompact::_last_gc_live_oops = NULL;
87 GrowableArray<HeapWord*>* PSParallelCompact::_last_gc_live_oops_moved_to = NULL;
88 GrowableArray<size_t> * PSParallelCompact::_last_gc_live_oops_size = NULL;
89 #endif
90
91 void SplitInfo::record(size_t src_region_idx, size_t partial_obj_size,
92 HeapWord* destination)
93 {
94 assert(src_region_idx != 0, "invalid src_region_idx");
95 assert(partial_obj_size != 0, "invalid partial_obj_size argument");
96 assert(destination != NULL, "invalid destination argument");
97
98 _src_region_idx = src_region_idx;
99 _partial_obj_size = partial_obj_size;
100 _destination = destination;
101
102 // These fields may not be updated below, so make sure they're clear.
103 assert(_dest_region_addr == NULL, "should have been cleared");
104 assert(_first_src_addr == NULL, "should have been cleared");
105
106 // Determine the number of destination regions for the partial object.
107 HeapWord* const last_word = destination + partial_obj_size - 1;
108 const ParallelCompactData& sd = PSParallelCompact::summary_data();
109 HeapWord* const beg_region_addr = sd.region_align_down(destination);
110 HeapWord* const end_region_addr = sd.region_align_down(last_word);
111
112 if (beg_region_addr == end_region_addr) {
113 // One destination region.
114 _destination_count = 1;
115 if (end_region_addr == destination) {
116 // The destination falls on a region boundary, thus the first word of the
117 // partial object will be the first word copied to the destination region.
118 _dest_region_addr = end_region_addr;
119 _first_src_addr = sd.region_to_addr(src_region_idx);
120 }
121 } else {
122 // Two destination regions. When copied, the partial object will cross a
123 // destination region boundary, so a word somewhere within the partial
124 // object will be the first word copied to the second destination region.
125 _destination_count = 2;
126 _dest_region_addr = end_region_addr;
127 const size_t ofs = pointer_delta(end_region_addr, destination);
128 assert(ofs < _partial_obj_size, "sanity");
129 _first_src_addr = sd.region_to_addr(src_region_idx) + ofs;
130 }
131 }
132
133 void SplitInfo::clear()
134 {
135 _src_region_idx = 0;
136 _partial_obj_size = 0;
137 _destination = NULL;
138 _destination_count = 0;
139 _dest_region_addr = NULL;
140 _first_src_addr = NULL;
141 assert(!is_valid(), "sanity");
142 }
143
144 #ifdef ASSERT
145 void SplitInfo::verify_clear()
146 {
147 assert(_src_region_idx == 0, "not clear");
148 assert(_partial_obj_size == 0, "not clear");
149 assert(_destination == NULL, "not clear");
150 assert(_destination_count == 0, "not clear");
151 assert(_dest_region_addr == NULL, "not clear");
152 assert(_first_src_addr == NULL, "not clear");
153 }
154 #endif // #ifdef ASSERT
155
156
157 #ifndef PRODUCT
158 const char* PSParallelCompact::space_names[] = {
159 "perm", "old ", "eden", "from", "to "
160 };
161
162 void PSParallelCompact::print_region_ranges()
163 {
164 tty->print_cr("space bottom top end new_top");
165 tty->print_cr("------ ---------- ---------- ---------- ----------");
166
167 for (unsigned int id = 0; id < last_space_id; ++id) {
168 const MutableSpace* space = _space_info[id].space();
169 tty->print_cr("%u %s "
170 SIZE_FORMAT_W(10) " " SIZE_FORMAT_W(10) " "
171 SIZE_FORMAT_W(10) " " SIZE_FORMAT_W(10) " ",
172 id, space_names[id],
173 summary_data().addr_to_region_idx(space->bottom()),
174 summary_data().addr_to_region_idx(space->top()),
175 summary_data().addr_to_region_idx(space->end()),
176 summary_data().addr_to_region_idx(_space_info[id].new_top()));
177 }
178 }
179
180 void
181 print_generic_summary_region(size_t i, const ParallelCompactData::RegionData* c)
182 {
183 #define REGION_IDX_FORMAT SIZE_FORMAT_W(7)
184 #define REGION_DATA_FORMAT SIZE_FORMAT_W(5)
185
186 ParallelCompactData& sd = PSParallelCompact::summary_data();
187 size_t dci = c->destination() ? sd.addr_to_region_idx(c->destination()) : 0;
188 tty->print_cr(REGION_IDX_FORMAT " " PTR_FORMAT " "
189 REGION_IDX_FORMAT " " PTR_FORMAT " "
190 REGION_DATA_FORMAT " " REGION_DATA_FORMAT " "
191 REGION_DATA_FORMAT " " REGION_IDX_FORMAT " %d",
192 i, c->data_location(), dci, c->destination(),
193 c->partial_obj_size(), c->live_obj_size(),
194 c->data_size(), c->source_region(), c->destination_count());
195
196 #undef REGION_IDX_FORMAT
197 #undef REGION_DATA_FORMAT
198 }
199
200 void
201 print_generic_summary_data(ParallelCompactData& summary_data,
202 HeapWord* const beg_addr,
203 HeapWord* const end_addr)
204 {
205 size_t total_words = 0;
206 size_t i = summary_data.addr_to_region_idx(beg_addr);
207 const size_t last = summary_data.addr_to_region_idx(end_addr);
208 HeapWord* pdest = 0;
209
210 while (i <= last) {
211 ParallelCompactData::RegionData* c = summary_data.region(i);
212 if (c->data_size() != 0 || c->destination() != pdest) {
213 print_generic_summary_region(i, c);
214 total_words += c->data_size();
215 pdest = c->destination();
216 }
217 ++i;
218 }
219
220 tty->print_cr("summary_data_bytes=" SIZE_FORMAT, total_words * HeapWordSize);
221 }
222
223 void
224 print_generic_summary_data(ParallelCompactData& summary_data,
225 SpaceInfo* space_info)
226 {
227 for (unsigned int id = 0; id < PSParallelCompact::last_space_id; ++id) {
228 const MutableSpace* space = space_info[id].space();
229 print_generic_summary_data(summary_data, space->bottom(),
230 MAX2(space->top(), space_info[id].new_top()));
231 }
232 }
233
234 void
235 print_initial_summary_region(size_t i,
236 const ParallelCompactData::RegionData* c,
237 bool newline = true)
238 {
239 tty->print(SIZE_FORMAT_W(5) " " PTR_FORMAT " "
240 SIZE_FORMAT_W(5) " " SIZE_FORMAT_W(5) " "
241 SIZE_FORMAT_W(5) " " SIZE_FORMAT_W(5) " %d",
242 i, c->destination(),
243 c->partial_obj_size(), c->live_obj_size(),
244 c->data_size(), c->source_region(), c->destination_count());
245 if (newline) tty->cr();
246 }
247
248 void
249 print_initial_summary_data(ParallelCompactData& summary_data,
250 const MutableSpace* space) {
251 if (space->top() == space->bottom()) {
252 return;
253 }
254
255 const size_t region_size = ParallelCompactData::RegionSize;
256 typedef ParallelCompactData::RegionData RegionData;
257 HeapWord* const top_aligned_up = summary_data.region_align_up(space->top());
258 const size_t end_region = summary_data.addr_to_region_idx(top_aligned_up);
259 const RegionData* c = summary_data.region(end_region - 1);
260 HeapWord* end_addr = c->destination() + c->data_size();
261 const size_t live_in_space = pointer_delta(end_addr, space->bottom());
262
263 // Print (and count) the full regions at the beginning of the space.
264 size_t full_region_count = 0;
265 size_t i = summary_data.addr_to_region_idx(space->bottom());
266 while (i < end_region && summary_data.region(i)->data_size() == region_size) {
267 print_initial_summary_region(i, summary_data.region(i));
268 ++full_region_count;
269 ++i;
270 }
271
272 size_t live_to_right = live_in_space - full_region_count * region_size;
273
274 double max_reclaimed_ratio = 0.0;
275 size_t max_reclaimed_ratio_region = 0;
276 size_t max_dead_to_right = 0;
277 size_t max_live_to_right = 0;
278
279 // Print the 'reclaimed ratio' for regions while there is something live in
280 // the region or to the right of it. The remaining regions are empty (and
281 // uninteresting), and computing the ratio will result in division by 0.
282 while (i < end_region && live_to_right > 0) {
283 c = summary_data.region(i);
284 HeapWord* const region_addr = summary_data.region_to_addr(i);
285 const size_t used_to_right = pointer_delta(space->top(), region_addr);
286 const size_t dead_to_right = used_to_right - live_to_right;
287 const double reclaimed_ratio = double(dead_to_right) / live_to_right;
288
289 if (reclaimed_ratio > max_reclaimed_ratio) {
290 max_reclaimed_ratio = reclaimed_ratio;
291 max_reclaimed_ratio_region = i;
292 max_dead_to_right = dead_to_right;
293 max_live_to_right = live_to_right;
294 }
295
296 print_initial_summary_region(i, c, false);
297 tty->print_cr(" %12.10f " SIZE_FORMAT_W(10) " " SIZE_FORMAT_W(10),
298 reclaimed_ratio, dead_to_right, live_to_right);
299
300 live_to_right -= c->data_size();
301 ++i;
302 }
303
304 // Any remaining regions are empty. Print one more if there is one.
305 if (i < end_region) {
306 print_initial_summary_region(i, summary_data.region(i));
307 }
308
309 tty->print_cr("max: " SIZE_FORMAT_W(4) " d2r=" SIZE_FORMAT_W(10) " "
310 "l2r=" SIZE_FORMAT_W(10) " max_ratio=%14.12f",
311 max_reclaimed_ratio_region, max_dead_to_right,
312 max_live_to_right, max_reclaimed_ratio);
313 }
314
315 void
316 print_initial_summary_data(ParallelCompactData& summary_data,
317 SpaceInfo* space_info) {
318 unsigned int id = PSParallelCompact::perm_space_id;
319 const MutableSpace* space;
320 do {
321 space = space_info[id].space();
322 print_initial_summary_data(summary_data, space);
323 } while (++id < PSParallelCompact::eden_space_id);
324
325 do {
326 space = space_info[id].space();
327 print_generic_summary_data(summary_data, space->bottom(), space->top());
328 } while (++id < PSParallelCompact::last_space_id);
329 }
330 #endif // #ifndef PRODUCT
331
332 #ifdef ASSERT
333 size_t add_obj_count;
334 size_t add_obj_size;
335 size_t mark_bitmap_count;
336 size_t mark_bitmap_size;
337 #endif // #ifdef ASSERT
338
339 ParallelCompactData::ParallelCompactData()
340 {
341 _region_start = 0;
342
343 _region_vspace = 0;
344 _region_data = 0;
345 _region_count = 0;
346 }
347
348 bool ParallelCompactData::initialize(MemRegion covered_region)
349 {
350 _region_start = covered_region.start();
351 const size_t region_size = covered_region.word_size();
352 DEBUG_ONLY(_region_end = _region_start + region_size;)
353
354 assert(region_align_down(_region_start) == _region_start,
355 "region start not aligned");
356 assert((region_size & RegionSizeOffsetMask) == 0,
357 "region size not a multiple of RegionSize");
358
359 bool result = initialize_region_data(region_size);
360
361 return result;
362 }
363
364 PSVirtualSpace*
365 ParallelCompactData::create_vspace(size_t count, size_t element_size)
366 {
367 const size_t raw_bytes = count * element_size;
368 const size_t page_sz = os::page_size_for_region(raw_bytes, raw_bytes, 10);
369 const size_t granularity = os::vm_allocation_granularity();
370 const size_t bytes = align_size_up(raw_bytes, MAX2(page_sz, granularity));
371
372 const size_t rs_align = page_sz == (size_t) os::vm_page_size() ? 0 :
373 MAX2(page_sz, granularity);
374 ReservedSpace rs(bytes, rs_align, rs_align > 0);
375 os::trace_page_sizes("par compact", raw_bytes, raw_bytes, page_sz, rs.base(),
376 rs.size());
377 PSVirtualSpace* vspace = new PSVirtualSpace(rs, page_sz);
378 if (vspace != 0) {
379 if (vspace->expand_by(bytes)) {
380 return vspace;
381 }
382 delete vspace;
383 // Release memory reserved in the space.
384 rs.release();
385 }
386
387 return 0;
388 }
389
390 bool ParallelCompactData::initialize_region_data(size_t region_size)
391 {
392 const size_t count = (region_size + RegionSizeOffsetMask) >> Log2RegionSize;
393 _region_vspace = create_vspace(count, sizeof(RegionData));
394 if (_region_vspace != 0) {
395 _region_data = (RegionData*)_region_vspace->reserved_low_addr();
396 _region_count = count;
397 return true;
398 }
399 return false;
400 }
401
402 void ParallelCompactData::clear()
403 {
404 memset(_region_data, 0, _region_vspace->committed_size());
405 }
406
407 void ParallelCompactData::clear_range(size_t beg_region, size_t end_region) {
408 assert(beg_region <= _region_count, "beg_region out of range");
409 assert(end_region <= _region_count, "end_region out of range");
410
411 const size_t region_cnt = end_region - beg_region;
412 memset(_region_data + beg_region, 0, region_cnt * sizeof(RegionData));
413 }
414
415 HeapWord* ParallelCompactData::partial_obj_end(size_t region_idx) const
416 {
417 const RegionData* cur_cp = region(region_idx);
418 const RegionData* const end_cp = region(region_count() - 1);
419
420 HeapWord* result = region_to_addr(region_idx);
421 if (cur_cp < end_cp) {
422 do {
423 result += cur_cp->partial_obj_size();
424 } while (cur_cp->partial_obj_size() == RegionSize && ++cur_cp < end_cp);
425 }
426 return result;
427 }
428
429 void ParallelCompactData::add_obj(HeapWord* addr, size_t len)
430 {
431 const size_t obj_ofs = pointer_delta(addr, _region_start);
432 const size_t beg_region = obj_ofs >> Log2RegionSize;
433 const size_t end_region = (obj_ofs + len - 1) >> Log2RegionSize;
434
435 DEBUG_ONLY(Atomic::inc_ptr(&add_obj_count);)
436 DEBUG_ONLY(Atomic::add_ptr(len, &add_obj_size);)
437
438 if (beg_region == end_region) {
439 // All in one region.
440 _region_data[beg_region].add_live_obj(len);
441 return;
442 }
443
444 // First region.
445 const size_t beg_ofs = region_offset(addr);
446 _region_data[beg_region].add_live_obj(RegionSize - beg_ofs);
447
448 klassOop klass = ((oop)addr)->klass();
449 // Middle regions--completely spanned by this object.
450 for (size_t region = beg_region + 1; region < end_region; ++region) {
451 _region_data[region].set_partial_obj_size(RegionSize);
452 _region_data[region].set_partial_obj_addr(addr);
453 }
454
455 // Last region.
456 const size_t end_ofs = region_offset(addr + len - 1);
457 _region_data[end_region].set_partial_obj_size(end_ofs + 1);
458 _region_data[end_region].set_partial_obj_addr(addr);
459 }
460
461 void
462 ParallelCompactData::summarize_dense_prefix(HeapWord* beg, HeapWord* end)
463 {
464 assert(region_offset(beg) == 0, "not RegionSize aligned");
465 assert(region_offset(end) == 0, "not RegionSize aligned");
466
467 size_t cur_region = addr_to_region_idx(beg);
468 const size_t end_region = addr_to_region_idx(end);
469 HeapWord* addr = beg;
470 while (cur_region < end_region) {
471 _region_data[cur_region].set_destination(addr);
472 _region_data[cur_region].set_destination_count(0);
473 _region_data[cur_region].set_source_region(cur_region);
474 _region_data[cur_region].set_data_location(addr);
475
476 // Update live_obj_size so the region appears completely full.
477 size_t live_size = RegionSize - _region_data[cur_region].partial_obj_size();
478 _region_data[cur_region].set_live_obj_size(live_size);
479
480 ++cur_region;
481 addr += RegionSize;
482 }
483 }
484
485 // Find the point at which a space can be split and, if necessary, record the
486 // split point.
487 //
488 // If the current src region (which overflowed the destination space) doesn't
489 // have a partial object, the split point is at the beginning of the current src
490 // region (an "easy" split, no extra bookkeeping required).
491 //
492 // If the current src region has a partial object, the split point is in the
493 // region where that partial object starts (call it the split_region). If
494 // split_region has a partial object, then the split point is just after that
495 // partial object (a "hard" split where we have to record the split data and
496 // zero the partial_obj_size field). With a "hard" split, we know that the
497 // partial_obj ends within split_region because the partial object that caused
498 // the overflow starts in split_region. If split_region doesn't have a partial
499 // obj, then the split is at the beginning of split_region (another "easy"
500 // split).
501 HeapWord*
502 ParallelCompactData::summarize_split_space(size_t src_region,
503 SplitInfo& split_info,
504 HeapWord* destination,
505 HeapWord* target_end,
506 HeapWord** target_next)
507 {
508 assert(destination <= target_end, "sanity");
509 assert(destination + _region_data[src_region].data_size() > target_end,
510 "region should not fit into target space");
511 assert(is_region_aligned(target_end), "sanity");
512
513 size_t split_region = src_region;
514 HeapWord* split_destination = destination;
515 size_t partial_obj_size = _region_data[src_region].partial_obj_size();
516
517 if (destination + partial_obj_size > target_end) {
518 // The split point is just after the partial object (if any) in the
519 // src_region that contains the start of the object that overflowed the
520 // destination space.
521 //
522 // Find the start of the "overflow" object and set split_region to the
523 // region containing it.
524 HeapWord* const overflow_obj = _region_data[src_region].partial_obj_addr();
525 split_region = addr_to_region_idx(overflow_obj);
526
527 // Clear the source_region field of all destination regions whose first word
528 // came from data after the split point (a non-null source_region field
529 // implies a region must be filled).
530 //
531 // An alternative to the simple loop below: clear during post_compact(),
532 // which uses memcpy instead of individual stores, and is easy to
533 // parallelize. (The downside is that it clears the entire RegionData
534 // object as opposed to just one field.)
535 //
536 // post_compact() would have to clear the summary data up to the highest
537 // address that was written during the summary phase, which would be
538 //
539 // max(top, max(new_top, clear_top))
540 //
541 // where clear_top is a new field in SpaceInfo. Would have to set clear_top
542 // to target_end.
543 const RegionData* const sr = region(split_region);
544 const size_t beg_idx =
545 addr_to_region_idx(region_align_up(sr->destination() +
546 sr->partial_obj_size()));
547 const size_t end_idx = addr_to_region_idx(target_end);
548
549 if (TraceParallelOldGCSummaryPhase) {
550 gclog_or_tty->print_cr("split: clearing source_region field in ["
551 SIZE_FORMAT ", " SIZE_FORMAT ")",
552 beg_idx, end_idx);
553 }
554 for (size_t idx = beg_idx; idx < end_idx; ++idx) {
555 _region_data[idx].set_source_region(0);
556 }
557
558 // Set split_destination and partial_obj_size to reflect the split region.
559 split_destination = sr->destination();
560 partial_obj_size = sr->partial_obj_size();
561 }
562
563 // The split is recorded only if a partial object extends onto the region.
564 if (partial_obj_size != 0) {
565 _region_data[split_region].set_partial_obj_size(0);
566 split_info.record(split_region, partial_obj_size, split_destination);
567 }
568
569 // Setup the continuation addresses.
570 *target_next = split_destination + partial_obj_size;
571 HeapWord* const source_next = region_to_addr(split_region) + partial_obj_size;
572
573 if (TraceParallelOldGCSummaryPhase) {
574 const char * split_type = partial_obj_size == 0 ? "easy" : "hard";
575 gclog_or_tty->print_cr("%s split: src=" PTR_FORMAT " src_c=" SIZE_FORMAT
576 " pos=" SIZE_FORMAT,
577 split_type, source_next, split_region,
578 partial_obj_size);
579 gclog_or_tty->print_cr("%s split: dst=" PTR_FORMAT " dst_c=" SIZE_FORMAT
580 " tn=" PTR_FORMAT,
581 split_type, split_destination,
582 addr_to_region_idx(split_destination),
583 *target_next);
584
585 if (partial_obj_size != 0) {
586 HeapWord* const po_beg = split_info.destination();
587 HeapWord* const po_end = po_beg + split_info.partial_obj_size();
588 gclog_or_tty->print_cr("%s split: "
589 "po_beg=" PTR_FORMAT " " SIZE_FORMAT " "
590 "po_end=" PTR_FORMAT " " SIZE_FORMAT,
591 split_type,
592 po_beg, addr_to_region_idx(po_beg),
593 po_end, addr_to_region_idx(po_end));
594 }
595 }
596
597 return source_next;
598 }
599
600 bool ParallelCompactData::summarize(SplitInfo& split_info,
601 HeapWord* source_beg, HeapWord* source_end,
602 HeapWord** source_next,
603 HeapWord* target_beg, HeapWord* target_end,
604 HeapWord** target_next)
605 {
606 if (TraceParallelOldGCSummaryPhase) {
607 HeapWord* const source_next_val = source_next == NULL ? NULL : *source_next;
608 tty->print_cr("sb=" PTR_FORMAT " se=" PTR_FORMAT " sn=" PTR_FORMAT
609 "tb=" PTR_FORMAT " te=" PTR_FORMAT " tn=" PTR_FORMAT,
610 source_beg, source_end, source_next_val,
611 target_beg, target_end, *target_next);
612 }
613
614 size_t cur_region = addr_to_region_idx(source_beg);
615 const size_t end_region = addr_to_region_idx(region_align_up(source_end));
616
617 HeapWord *dest_addr = target_beg;
618 while (cur_region < end_region) {
619 // The destination must be set even if the region has no data.
620 _region_data[cur_region].set_destination(dest_addr);
621
622 size_t words = _region_data[cur_region].data_size();
623 if (words > 0) {
624 // If cur_region does not fit entirely into the target space, find a point
625 // at which the source space can be 'split' so that part is copied to the
626 // target space and the rest is copied elsewhere.
627 if (dest_addr + words > target_end) {
628 assert(source_next != NULL, "source_next is NULL when splitting");
629 *source_next = summarize_split_space(cur_region, split_info, dest_addr,
630 target_end, target_next);
631 return false;
632 }
633
634 // Compute the destination_count for cur_region, and if necessary, update
635 // source_region for a destination region. The source_region field is
636 // updated if cur_region is the first (left-most) region to be copied to a
637 // destination region.
638 //
639 // The destination_count calculation is a bit subtle. A region that has
640 // data that compacts into itself does not count itself as a destination.
641 // This maintains the invariant that a zero count means the region is
642 // available and can be claimed and then filled.
643 uint destination_count = 0;
644 if (split_info.is_split(cur_region)) {
645 // The current region has been split: the partial object will be copied
646 // to one destination space and the remaining data will be copied to
647 // another destination space. Adjust the initial destination_count and,
648 // if necessary, set the source_region field if the partial object will
649 // cross a destination region boundary.
650 destination_count = split_info.destination_count();
651 if (destination_count == 2) {
652 size_t dest_idx = addr_to_region_idx(split_info.dest_region_addr());
653 _region_data[dest_idx].set_source_region(cur_region);
654 }
655 }
656
657 HeapWord* const last_addr = dest_addr + words - 1;
658 const size_t dest_region_1 = addr_to_region_idx(dest_addr);
659 const size_t dest_region_2 = addr_to_region_idx(last_addr);
660
661 // Initially assume that the destination regions will be the same and
662 // adjust the value below if necessary. Under this assumption, if
663 // cur_region == dest_region_2, then cur_region will be compacted
664 // completely into itself.
665 destination_count += cur_region == dest_region_2 ? 0 : 1;
666 if (dest_region_1 != dest_region_2) {
667 // Destination regions differ; adjust destination_count.
668 destination_count += 1;
669 // Data from cur_region will be copied to the start of dest_region_2.
670 _region_data[dest_region_2].set_source_region(cur_region);
671 } else if (region_offset(dest_addr) == 0) {
672 // Data from cur_region will be copied to the start of the destination
673 // region.
674 _region_data[dest_region_1].set_source_region(cur_region);
675 }
676
677 _region_data[cur_region].set_destination_count(destination_count);
678 _region_data[cur_region].set_data_location(region_to_addr(cur_region));
679 dest_addr += words;
680 }
681
682 ++cur_region;
683 }
684
685 *target_next = dest_addr;
686 return true;
687 }
688
689 HeapWord* ParallelCompactData::calc_new_pointer(HeapWord* addr) {
690 assert(addr != NULL, "Should detect NULL oop earlier");
691 assert(PSParallelCompact::gc_heap()->is_in(addr), "addr not in heap");
692 #ifdef ASSERT
693 if (PSParallelCompact::mark_bitmap()->is_unmarked(addr)) {
694 gclog_or_tty->print_cr("calc_new_pointer:: addr " PTR_FORMAT, addr);
695 }
696 #endif
697 assert(PSParallelCompact::mark_bitmap()->is_marked(addr), "obj not marked");
698
699 // Region covering the object.
700 size_t region_index = addr_to_region_idx(addr);
701 const RegionData* const region_ptr = region(region_index);
702 HeapWord* const region_addr = region_align_down(addr);
703
704 assert(addr < region_addr + RegionSize, "Region does not cover object");
705 assert(addr_to_region_ptr(region_addr) == region_ptr, "sanity check");
706
707 HeapWord* result = region_ptr->destination();
708
709 // If all the data in the region is live, then the new location of the object
710 // can be calculated from the destination of the region plus the offset of the
711 // object in the region.
712 if (region_ptr->data_size() == RegionSize) {
713 result += pointer_delta(addr, region_addr);
714 DEBUG_ONLY(PSParallelCompact::check_new_location(addr, result);)
715 return result;
716 }
717
718 // The new location of the object is
719 // region destination +
720 // size of the partial object extending onto the region +
721 // sizes of the live objects in the Region that are to the left of addr
722 const size_t partial_obj_size = region_ptr->partial_obj_size();
723 HeapWord* const search_start = region_addr + partial_obj_size;
724
725 const ParMarkBitMap* bitmap = PSParallelCompact::mark_bitmap();
726 size_t live_to_left = bitmap->live_words_in_range(search_start, oop(addr));
727
728 result += partial_obj_size + live_to_left;
729 DEBUG_ONLY(PSParallelCompact::check_new_location(addr, result);)
730 return result;
731 }
732
733 klassOop ParallelCompactData::calc_new_klass(klassOop old_klass) {
734 klassOop updated_klass;
735 if (PSParallelCompact::should_update_klass(old_klass)) {
736 updated_klass = (klassOop) calc_new_pointer(old_klass);
737 } else {
738 updated_klass = old_klass;
739 }
740
741 return updated_klass;
742 }
743
744 #ifdef ASSERT
745 void ParallelCompactData::verify_clear(const PSVirtualSpace* vspace)
746 {
747 const size_t* const beg = (const size_t*)vspace->committed_low_addr();
748 const size_t* const end = (const size_t*)vspace->committed_high_addr();
749 for (const size_t* p = beg; p < end; ++p) {
750 assert(*p == 0, "not zero");
751 }
752 }
753
754 void ParallelCompactData::verify_clear()
755 {
756 verify_clear(_region_vspace);
757 }
758 #endif // #ifdef ASSERT
759
760 #ifdef NOT_PRODUCT
761 ParallelCompactData::RegionData* debug_region(size_t region_index) {
762 ParallelCompactData& sd = PSParallelCompact::summary_data();
763 return sd.region(region_index);
764 }
765 #endif
766
767 elapsedTimer PSParallelCompact::_accumulated_time;
768 unsigned int PSParallelCompact::_total_invocations = 0;
769 unsigned int PSParallelCompact::_maximum_compaction_gc_num = 0;
770 jlong PSParallelCompact::_time_of_last_gc = 0;
771 CollectorCounters* PSParallelCompact::_counters = NULL;
772 ParMarkBitMap PSParallelCompact::_mark_bitmap;
773 ParallelCompactData PSParallelCompact::_summary_data;
774
775 PSParallelCompact::IsAliveClosure PSParallelCompact::_is_alive_closure;
776
777 void PSParallelCompact::IsAliveClosure::do_object(oop p) { ShouldNotReachHere(); }
778 bool PSParallelCompact::IsAliveClosure::do_object_b(oop p) { return mark_bitmap()->is_marked(p); }
779
780 void PSParallelCompact::KeepAliveClosure::do_oop(oop* p) { PSParallelCompact::KeepAliveClosure::do_oop_work(p); }
781 void PSParallelCompact::KeepAliveClosure::do_oop(narrowOop* p) { PSParallelCompact::KeepAliveClosure::do_oop_work(p); }
782
783 PSParallelCompact::AdjustPointerClosure PSParallelCompact::_adjust_root_pointer_closure(true);
784 PSParallelCompact::AdjustPointerClosure PSParallelCompact::_adjust_pointer_closure(false);
785
786 void PSParallelCompact::AdjustPointerClosure::do_oop(oop* p) { adjust_pointer(p, _is_root); }
787 void PSParallelCompact::AdjustPointerClosure::do_oop(narrowOop* p) { adjust_pointer(p, _is_root); }
788
789 void PSParallelCompact::FollowStackClosure::do_void() { _compaction_manager->follow_marking_stacks(); }
790
791 void PSParallelCompact::MarkAndPushClosure::do_oop(oop* p) { mark_and_push(_compaction_manager, p); }
792 void PSParallelCompact::MarkAndPushClosure::do_oop(narrowOop* p) { mark_and_push(_compaction_manager, p); }
793
794 void PSParallelCompact::post_initialize() {
795 ParallelScavengeHeap* heap = gc_heap();
796 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
797
798 MemRegion mr = heap->reserved_region();
799 _ref_processor = ReferenceProcessor::create_ref_processor(
800 mr, // span
801 true, // atomic_discovery
802 true, // mt_discovery
803 &_is_alive_closure,
804 ParallelGCThreads,
805 ParallelRefProcEnabled);
806 _counters = new CollectorCounters("PSParallelCompact", 1);
807
808 // Initialize static fields in ParCompactionManager.
809 ParCompactionManager::initialize(mark_bitmap());
810 }
811
812 bool PSParallelCompact::initialize() {
813 ParallelScavengeHeap* heap = gc_heap();
814 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
815 MemRegion mr = heap->reserved_region();
816
817 // Was the old gen get allocated successfully?
818 if (!heap->old_gen()->is_allocated()) {
819 return false;
820 }
821
822 initialize_space_info();
823 initialize_dead_wood_limiter();
824
825 if (!_mark_bitmap.initialize(mr)) {
826 vm_shutdown_during_initialization("Unable to allocate bit map for "
827 "parallel garbage collection for the requested heap size.");
828 return false;
829 }
830
831 if (!_summary_data.initialize(mr)) {
832 vm_shutdown_during_initialization("Unable to allocate tables for "
833 "parallel garbage collection for the requested heap size.");
834 return false;
835 }
836
837 return true;
838 }
839
840 void PSParallelCompact::initialize_space_info()
841 {
842 memset(&_space_info, 0, sizeof(_space_info));
843
844 ParallelScavengeHeap* heap = gc_heap();
845 PSYoungGen* young_gen = heap->young_gen();
846 MutableSpace* perm_space = heap->perm_gen()->object_space();
847
848 _space_info[perm_space_id].set_space(perm_space);
849 _space_info[old_space_id].set_space(heap->old_gen()->object_space());
850 _space_info[eden_space_id].set_space(young_gen->eden_space());
851 _space_info[from_space_id].set_space(young_gen->from_space());
852 _space_info[to_space_id].set_space(young_gen->to_space());
853
854 _space_info[perm_space_id].set_start_array(heap->perm_gen()->start_array());
855 _space_info[old_space_id].set_start_array(heap->old_gen()->start_array());
856
857 _space_info[perm_space_id].set_min_dense_prefix(perm_space->top());
858 if (TraceParallelOldGCDensePrefix) {
859 tty->print_cr("perm min_dense_prefix=" PTR_FORMAT,
860 _space_info[perm_space_id].min_dense_prefix());
861 }
862 }
863
864 void PSParallelCompact::initialize_dead_wood_limiter()
865 {
866 const size_t max = 100;
867 _dwl_mean = double(MIN2(ParallelOldDeadWoodLimiterMean, max)) / 100.0;
868 _dwl_std_dev = double(MIN2(ParallelOldDeadWoodLimiterStdDev, max)) / 100.0;
869 _dwl_first_term = 1.0 / (sqrt(2.0 * M_PI) * _dwl_std_dev);
870 DEBUG_ONLY(_dwl_initialized = true;)
871 _dwl_adjustment = normal_distribution(1.0);
872 }
873
874 // Simple class for storing info about the heap at the start of GC, to be used
875 // after GC for comparison/printing.
876 class PreGCValues {
877 public:
878 PreGCValues() { }
879 PreGCValues(ParallelScavengeHeap* heap) { fill(heap); }
880
881 void fill(ParallelScavengeHeap* heap) {
882 _heap_used = heap->used();
883 _young_gen_used = heap->young_gen()->used_in_bytes();
884 _old_gen_used = heap->old_gen()->used_in_bytes();
885 _perm_gen_used = heap->perm_gen()->used_in_bytes();
886 };
887
888 size_t heap_used() const { return _heap_used; }
889 size_t young_gen_used() const { return _young_gen_used; }
890 size_t old_gen_used() const { return _old_gen_used; }
891 size_t perm_gen_used() const { return _perm_gen_used; }
892
893 private:
894 size_t _heap_used;
895 size_t _young_gen_used;
896 size_t _old_gen_used;
897 size_t _perm_gen_used;
898 };
899
900 void
901 PSParallelCompact::clear_data_covering_space(SpaceId id)
902 {
903 // At this point, top is the value before GC, new_top() is the value that will
904 // be set at the end of GC. The marking bitmap is cleared to top; nothing
905 // should be marked above top. The summary data is cleared to the larger of
906 // top & new_top.
907 MutableSpace* const space = _space_info[id].space();
908 HeapWord* const bot = space->bottom();
909 HeapWord* const top = space->top();
910 HeapWord* const max_top = MAX2(top, _space_info[id].new_top());
911
912 const idx_t beg_bit = _mark_bitmap.addr_to_bit(bot);
913 const idx_t end_bit = BitMap::word_align_up(_mark_bitmap.addr_to_bit(top));
914 _mark_bitmap.clear_range(beg_bit, end_bit);
915
916 const size_t beg_region = _summary_data.addr_to_region_idx(bot);
917 const size_t end_region =
918 _summary_data.addr_to_region_idx(_summary_data.region_align_up(max_top));
919 _summary_data.clear_range(beg_region, end_region);
920
921 // Clear the data used to 'split' regions.
922 SplitInfo& split_info = _space_info[id].split_info();
923 if (split_info.is_valid()) {
924 split_info.clear();
925 }
926 DEBUG_ONLY(split_info.verify_clear();)
927 }
928
929 void PSParallelCompact::pre_compact(PreGCValues* pre_gc_values)
930 {
931 // Update the from & to space pointers in space_info, since they are swapped
932 // at each young gen gc. Do the update unconditionally (even though a
933 // promotion failure does not swap spaces) because an unknown number of minor
934 // collections will have swapped the spaces an unknown number of times.
935 TraceTime tm("pre compact", print_phases(), true, gclog_or_tty);
936 ParallelScavengeHeap* heap = gc_heap();
937 _space_info[from_space_id].set_space(heap->young_gen()->from_space());
938 _space_info[to_space_id].set_space(heap->young_gen()->to_space());
939
940 pre_gc_values->fill(heap);
941
942 ParCompactionManager::reset();
943 NOT_PRODUCT(_mark_bitmap.reset_counters());
944 DEBUG_ONLY(add_obj_count = add_obj_size = 0;)
945 DEBUG_ONLY(mark_bitmap_count = mark_bitmap_size = 0;)
946
947 // Increment the invocation count
948 heap->increment_total_collections(true);
949
950 // We need to track unique mark sweep invocations as well.
951 _total_invocations++;
952
953 if (PrintHeapAtGC) {
954 Universe::print_heap_before_gc();
955 }
956
957 // Fill in TLABs
958 heap->accumulate_statistics_all_tlabs();
959 heap->ensure_parsability(true); // retire TLABs
960
961 if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) {
962 HandleMark hm; // Discard invalid handles created during verification
963 gclog_or_tty->print(" VerifyBeforeGC:");
964 Universe::verify(true);
965 }
966
967 // Verify object start arrays
968 if (VerifyObjectStartArray &&
969 VerifyBeforeGC) {
970 heap->old_gen()->verify_object_start_array();
971 heap->perm_gen()->verify_object_start_array();
972 }
973
974 DEBUG_ONLY(mark_bitmap()->verify_clear();)
975 DEBUG_ONLY(summary_data().verify_clear();)
976
977 // Have worker threads release resources the next time they run a task.
978 gc_task_manager()->release_all_resources();
979 }
980
981 void PSParallelCompact::post_compact()
982 {
983 TraceTime tm("post compact", print_phases(), true, gclog_or_tty);
984
985 for (unsigned int id = perm_space_id; id < last_space_id; ++id) {
986 // Clear the marking bitmap, summary data and split info.
987 clear_data_covering_space(SpaceId(id));
988 // Update top(). Must be done after clearing the bitmap and summary data.
989 _space_info[id].publish_new_top();
990 }
991
992 MutableSpace* const eden_space = _space_info[eden_space_id].space();
993 MutableSpace* const from_space = _space_info[from_space_id].space();
994 MutableSpace* const to_space = _space_info[to_space_id].space();
995
996 ParallelScavengeHeap* heap = gc_heap();
997 bool eden_empty = eden_space->is_empty();
998 if (!eden_empty) {
999 eden_empty = absorb_live_data_from_eden(heap->size_policy(),
1000 heap->young_gen(), heap->old_gen());
1001 }
1002
1003 // Update heap occupancy information which is used as input to the soft ref
1004 // clearing policy at the next gc.
1005 Universe::update_heap_info_at_gc();
1006
1007 bool young_gen_empty = eden_empty && from_space->is_empty() &&
1008 to_space->is_empty();
1009
1010 BarrierSet* bs = heap->barrier_set();
1011 if (bs->is_a(BarrierSet::ModRef)) {
1012 ModRefBarrierSet* modBS = (ModRefBarrierSet*)bs;
1013 MemRegion old_mr = heap->old_gen()->reserved();
1014 MemRegion perm_mr = heap->perm_gen()->reserved();
1015 assert(perm_mr.end() <= old_mr.start(), "Generations out of order");
1016
1017 if (young_gen_empty) {
1018 modBS->clear(MemRegion(perm_mr.start(), old_mr.end()));
1019 } else {
1020 modBS->invalidate(MemRegion(perm_mr.start(), old_mr.end()));
1021 }
1022 }
1023
1024 Threads::gc_epilogue();
1025 CodeCache::gc_epilogue();
1026
1027 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
1028
1029 ref_processor()->enqueue_discovered_references(NULL);
1030
1031 if (ZapUnusedHeapArea) {
1032 heap->gen_mangle_unused_area();
1033 }
1034
1035 // Update time of last GC
1036 reset_millis_since_last_gc();
1037 }
1038
1039 HeapWord*
1040 PSParallelCompact::compute_dense_prefix_via_density(const SpaceId id,
1041 bool maximum_compaction)
1042 {
1043 const size_t region_size = ParallelCompactData::RegionSize;
1044 const ParallelCompactData& sd = summary_data();
1045
1046 const MutableSpace* const space = _space_info[id].space();
1047 HeapWord* const top_aligned_up = sd.region_align_up(space->top());
1048 const RegionData* const beg_cp = sd.addr_to_region_ptr(space->bottom());
1049 const RegionData* const end_cp = sd.addr_to_region_ptr(top_aligned_up);
1050
1051 // Skip full regions at the beginning of the space--they are necessarily part
1052 // of the dense prefix.
1053 size_t full_count = 0;
1054 const RegionData* cp;
1055 for (cp = beg_cp; cp < end_cp && cp->data_size() == region_size; ++cp) {
1056 ++full_count;
1057 }
1058
1059 assert(total_invocations() >= _maximum_compaction_gc_num, "sanity");
1060 const size_t gcs_since_max = total_invocations() - _maximum_compaction_gc_num;
1061 const bool interval_ended = gcs_since_max > HeapMaximumCompactionInterval;
1062 if (maximum_compaction || cp == end_cp || interval_ended) {
1063 _maximum_compaction_gc_num = total_invocations();
1064 return sd.region_to_addr(cp);
1065 }
1066
1067 HeapWord* const new_top = _space_info[id].new_top();
1068 const size_t space_live = pointer_delta(new_top, space->bottom());
1069 const size_t space_used = space->used_in_words();
1070 const size_t space_capacity = space->capacity_in_words();
1071
1072 const double cur_density = double(space_live) / space_capacity;
1073 const double deadwood_density =
1074 (1.0 - cur_density) * (1.0 - cur_density) * cur_density * cur_density;
1075 const size_t deadwood_goal = size_t(space_capacity * deadwood_density);
1076
1077 if (TraceParallelOldGCDensePrefix) {
1078 tty->print_cr("cur_dens=%5.3f dw_dens=%5.3f dw_goal=" SIZE_FORMAT,
1079 cur_density, deadwood_density, deadwood_goal);
1080 tty->print_cr("space_live=" SIZE_FORMAT " " "space_used=" SIZE_FORMAT " "
1081 "space_cap=" SIZE_FORMAT,
1082 space_live, space_used,
1083 space_capacity);
1084 }
1085
1086 // XXX - Use binary search?
1087 HeapWord* dense_prefix = sd.region_to_addr(cp);
1088 const RegionData* full_cp = cp;
1089 const RegionData* const top_cp = sd.addr_to_region_ptr(space->top() - 1);
1090 while (cp < end_cp) {
1091 HeapWord* region_destination = cp->destination();
1092 const size_t cur_deadwood = pointer_delta(dense_prefix, region_destination);
1093 if (TraceParallelOldGCDensePrefix && Verbose) {
1094 tty->print_cr("c#=" SIZE_FORMAT_W(4) " dst=" PTR_FORMAT " "
1095 "dp=" SIZE_FORMAT_W(8) " " "cdw=" SIZE_FORMAT_W(8),
1096 sd.region(cp), region_destination,
1097 dense_prefix, cur_deadwood);
1098 }
1099
1100 if (cur_deadwood >= deadwood_goal) {
1101 // Found the region that has the correct amount of deadwood to the left.
1102 // This typically occurs after crossing a fairly sparse set of regions, so
1103 // iterate backwards over those sparse regions, looking for the region
1104 // that has the lowest density of live objects 'to the right.'
1105 size_t space_to_left = sd.region(cp) * region_size;
1106 size_t live_to_left = space_to_left - cur_deadwood;
1107 size_t space_to_right = space_capacity - space_to_left;
1108 size_t live_to_right = space_live - live_to_left;
1109 double density_to_right = double(live_to_right) / space_to_right;
1110 while (cp > full_cp) {
1111 --cp;
1112 const size_t prev_region_live_to_right = live_to_right -
1113 cp->data_size();
1114 const size_t prev_region_space_to_right = space_to_right + region_size;
1115 double prev_region_density_to_right =
1116 double(prev_region_live_to_right) / prev_region_space_to_right;
1117 if (density_to_right <= prev_region_density_to_right) {
1118 return dense_prefix;
1119 }
1120 if (TraceParallelOldGCDensePrefix && Verbose) {
1121 tty->print_cr("backing up from c=" SIZE_FORMAT_W(4) " d2r=%10.8f "
1122 "pc_d2r=%10.8f", sd.region(cp), density_to_right,
1123 prev_region_density_to_right);
1124 }
1125 dense_prefix -= region_size;
1126 live_to_right = prev_region_live_to_right;
1127 space_to_right = prev_region_space_to_right;
1128 density_to_right = prev_region_density_to_right;
1129 }
1130 return dense_prefix;
1131 }
1132
1133 dense_prefix += region_size;
1134 ++cp;
1135 }
1136
1137 return dense_prefix;
1138 }
1139
1140 #ifndef PRODUCT
1141 void PSParallelCompact::print_dense_prefix_stats(const char* const algorithm,
1142 const SpaceId id,
1143 const bool maximum_compaction,
1144 HeapWord* const addr)
1145 {
1146 const size_t region_idx = summary_data().addr_to_region_idx(addr);
1147 RegionData* const cp = summary_data().region(region_idx);
1148 const MutableSpace* const space = _space_info[id].space();
1149 HeapWord* const new_top = _space_info[id].new_top();
1150
1151 const size_t space_live = pointer_delta(new_top, space->bottom());
1152 const size_t dead_to_left = pointer_delta(addr, cp->destination());
1153 const size_t space_cap = space->capacity_in_words();
1154 const double dead_to_left_pct = double(dead_to_left) / space_cap;
1155 const size_t live_to_right = new_top - cp->destination();
1156 const size_t dead_to_right = space->top() - addr - live_to_right;
1157
1158 tty->print_cr("%s=" PTR_FORMAT " dpc=" SIZE_FORMAT_W(5) " "
1159 "spl=" SIZE_FORMAT " "
1160 "d2l=" SIZE_FORMAT " d2l%%=%6.4f "
1161 "d2r=" SIZE_FORMAT " l2r=" SIZE_FORMAT
1162 " ratio=%10.8f",
1163 algorithm, addr, region_idx,
1164 space_live,
1165 dead_to_left, dead_to_left_pct,
1166 dead_to_right, live_to_right,
1167 double(dead_to_right) / live_to_right);
1168 }
1169 #endif // #ifndef PRODUCT
1170
1171 // Return a fraction indicating how much of the generation can be treated as
1172 // "dead wood" (i.e., not reclaimed). The function uses a normal distribution
1173 // based on the density of live objects in the generation to determine a limit,
1174 // which is then adjusted so the return value is min_percent when the density is
1175 // 1.
1176 //
1177 // The following table shows some return values for a different values of the
1178 // standard deviation (ParallelOldDeadWoodLimiterStdDev); the mean is 0.5 and
1179 // min_percent is 1.
1180 //
1181 // fraction allowed as dead wood
1182 // -----------------------------------------------------------------
1183 // density std_dev=70 std_dev=75 std_dev=80 std_dev=85 std_dev=90 std_dev=95
1184 // ------- ---------- ---------- ---------- ---------- ---------- ----------
1185 // 0.00000 0.01000000 0.01000000 0.01000000 0.01000000 0.01000000 0.01000000
1186 // 0.05000 0.03193096 0.02836880 0.02550828 0.02319280 0.02130337 0.01974941
1187 // 0.10000 0.05247504 0.04547452 0.03988045 0.03537016 0.03170171 0.02869272
1188 // 0.15000 0.07135702 0.06111390 0.05296419 0.04641639 0.04110601 0.03676066
1189 // 0.20000 0.08831616 0.07509618 0.06461766 0.05622444 0.04943437 0.04388975
1190 // 0.25000 0.10311208 0.08724696 0.07471205 0.06469760 0.05661313 0.05002313
1191 // 0.30000 0.11553050 0.09741183 0.08313394 0.07175114 0.06257797 0.05511132
1192 // 0.35000 0.12538832 0.10545958 0.08978741 0.07731366 0.06727491 0.05911289
1193 // 0.40000 0.13253818 0.11128511 0.09459590 0.08132834 0.07066107 0.06199500
1194 // 0.45000 0.13687208 0.11481163 0.09750361 0.08375387 0.07270534 0.06373386
1195 // 0.50000 0.13832410 0.11599237 0.09847664 0.08456518 0.07338887 0.06431510
1196 // 0.55000 0.13687208 0.11481163 0.09750361 0.08375387 0.07270534 0.06373386
1197 // 0.60000 0.13253818 0.11128511 0.09459590 0.08132834 0.07066107 0.06199500
1198 // 0.65000 0.12538832 0.10545958 0.08978741 0.07731366 0.06727491 0.05911289
1199 // 0.70000 0.11553050 0.09741183 0.08313394 0.07175114 0.06257797 0.05511132
1200 // 0.75000 0.10311208 0.08724696 0.07471205 0.06469760 0.05661313 0.05002313
1201 // 0.80000 0.08831616 0.07509618 0.06461766 0.05622444 0.04943437 0.04388975
1202 // 0.85000 0.07135702 0.06111390 0.05296419 0.04641639 0.04110601 0.03676066
1203 // 0.90000 0.05247504 0.04547452 0.03988045 0.03537016 0.03170171 0.02869272
1204 // 0.95000 0.03193096 0.02836880 0.02550828 0.02319280 0.02130337 0.01974941
1205 // 1.00000 0.01000000 0.01000000 0.01000000 0.01000000 0.01000000 0.01000000
1206
1207 double PSParallelCompact::dead_wood_limiter(double density, size_t min_percent)
1208 {
1209 assert(_dwl_initialized, "uninitialized");
1210
1211 // The raw limit is the value of the normal distribution at x = density.
1212 const double raw_limit = normal_distribution(density);
1213
1214 // Adjust the raw limit so it becomes the minimum when the density is 1.
1215 //
1216 // First subtract the adjustment value (which is simply the precomputed value
1217 // normal_distribution(1.0)); this yields a value of 0 when the density is 1.
1218 // Then add the minimum value, so the minimum is returned when the density is
1219 // 1. Finally, prevent negative values, which occur when the mean is not 0.5.
1220 const double min = double(min_percent) / 100.0;
1221 const double limit = raw_limit - _dwl_adjustment + min;
1222 return MAX2(limit, 0.0);
1223 }
1224
1225 ParallelCompactData::RegionData*
1226 PSParallelCompact::first_dead_space_region(const RegionData* beg,
1227 const RegionData* end)
1228 {
1229 const size_t region_size = ParallelCompactData::RegionSize;
1230 ParallelCompactData& sd = summary_data();
1231 size_t left = sd.region(beg);
1232 size_t right = end > beg ? sd.region(end) - 1 : left;
1233
1234 // Binary search.
1235 while (left < right) {
1236 // Equivalent to (left + right) / 2, but does not overflow.
1237 const size_t middle = left + (right - left) / 2;
1238 RegionData* const middle_ptr = sd.region(middle);
1239 HeapWord* const dest = middle_ptr->destination();
1240 HeapWord* const addr = sd.region_to_addr(middle);
1241 assert(dest != NULL, "sanity");
1242 assert(dest <= addr, "must move left");
1243
1244 if (middle > left && dest < addr) {
1245 right = middle - 1;
1246 } else if (middle < right && middle_ptr->data_size() == region_size) {
1247 left = middle + 1;
1248 } else {
1249 return middle_ptr;
1250 }
1251 }
1252 return sd.region(left);
1253 }
1254
1255 ParallelCompactData::RegionData*
1256 PSParallelCompact::dead_wood_limit_region(const RegionData* beg,
1257 const RegionData* end,
1258 size_t dead_words)
1259 {
1260 ParallelCompactData& sd = summary_data();
1261 size_t left = sd.region(beg);
1262 size_t right = end > beg ? sd.region(end) - 1 : left;
1263
1264 // Binary search.
1265 while (left < right) {
1266 // Equivalent to (left + right) / 2, but does not overflow.
1267 const size_t middle = left + (right - left) / 2;
1268 RegionData* const middle_ptr = sd.region(middle);
1269 HeapWord* const dest = middle_ptr->destination();
1270 HeapWord* const addr = sd.region_to_addr(middle);
1271 assert(dest != NULL, "sanity");
1272 assert(dest <= addr, "must move left");
1273
1274 const size_t dead_to_left = pointer_delta(addr, dest);
1275 if (middle > left && dead_to_left > dead_words) {
1276 right = middle - 1;
1277 } else if (middle < right && dead_to_left < dead_words) {
1278 left = middle + 1;
1279 } else {
1280 return middle_ptr;
1281 }
1282 }
1283 return sd.region(left);
1284 }
1285
1286 // The result is valid during the summary phase, after the initial summarization
1287 // of each space into itself, and before final summarization.
1288 inline double
1289 PSParallelCompact::reclaimed_ratio(const RegionData* const cp,
1290 HeapWord* const bottom,
1291 HeapWord* const top,
1292 HeapWord* const new_top)
1293 {
1294 ParallelCompactData& sd = summary_data();
1295
1296 assert(cp != NULL, "sanity");
1297 assert(bottom != NULL, "sanity");
1298 assert(top != NULL, "sanity");
1299 assert(new_top != NULL, "sanity");
1300 assert(top >= new_top, "summary data problem?");
1301 assert(new_top > bottom, "space is empty; should not be here");
1302 assert(new_top >= cp->destination(), "sanity");
1303 assert(top >= sd.region_to_addr(cp), "sanity");
1304
1305 HeapWord* const destination = cp->destination();
1306 const size_t dense_prefix_live = pointer_delta(destination, bottom);
1307 const size_t compacted_region_live = pointer_delta(new_top, destination);
1308 const size_t compacted_region_used = pointer_delta(top,
1309 sd.region_to_addr(cp));
1310 const size_t reclaimable = compacted_region_used - compacted_region_live;
1311
1312 const double divisor = dense_prefix_live + 1.25 * compacted_region_live;
1313 return double(reclaimable) / divisor;
1314 }
1315
1316 // Return the address of the end of the dense prefix, a.k.a. the start of the
1317 // compacted region. The address is always on a region boundary.
1318 //
1319 // Completely full regions at the left are skipped, since no compaction can
1320 // occur in those regions. Then the maximum amount of dead wood to allow is
1321 // computed, based on the density (amount live / capacity) of the generation;
1322 // the region with approximately that amount of dead space to the left is
1323 // identified as the limit region. Regions between the last completely full
1324 // region and the limit region are scanned and the one that has the best
1325 // (maximum) reclaimed_ratio() is selected.
1326 HeapWord*
1327 PSParallelCompact::compute_dense_prefix(const SpaceId id,
1328 bool maximum_compaction)
1329 {
1330 if (ParallelOldGCSplitALot) {
1331 if (_space_info[id].dense_prefix() != _space_info[id].space()->bottom()) {
1332 // The value was chosen to provoke splitting a young gen space; use it.
1333 return _space_info[id].dense_prefix();
1334 }
1335 }
1336
1337 const size_t region_size = ParallelCompactData::RegionSize;
1338 const ParallelCompactData& sd = summary_data();
1339
1340 const MutableSpace* const space = _space_info[id].space();
1341 HeapWord* const top = space->top();
1342 HeapWord* const top_aligned_up = sd.region_align_up(top);
1343 HeapWord* const new_top = _space_info[id].new_top();
1344 HeapWord* const new_top_aligned_up = sd.region_align_up(new_top);
1345 HeapWord* const bottom = space->bottom();
1346 const RegionData* const beg_cp = sd.addr_to_region_ptr(bottom);
1347 const RegionData* const top_cp = sd.addr_to_region_ptr(top_aligned_up);
1348 const RegionData* const new_top_cp =
1349 sd.addr_to_region_ptr(new_top_aligned_up);
1350
1351 // Skip full regions at the beginning of the space--they are necessarily part
1352 // of the dense prefix.
1353 const RegionData* const full_cp = first_dead_space_region(beg_cp, new_top_cp);
1354 assert(full_cp->destination() == sd.region_to_addr(full_cp) ||
1355 space->is_empty(), "no dead space allowed to the left");
1356 assert(full_cp->data_size() < region_size || full_cp == new_top_cp - 1,
1357 "region must have dead space");
1358
1359 // The gc number is saved whenever a maximum compaction is done, and used to
1360 // determine when the maximum compaction interval has expired. This avoids
1361 // successive max compactions for different reasons.
1362 assert(total_invocations() >= _maximum_compaction_gc_num, "sanity");
1363 const size_t gcs_since_max = total_invocations() - _maximum_compaction_gc_num;
1364 const bool interval_ended = gcs_since_max > HeapMaximumCompactionInterval ||
1365 total_invocations() == HeapFirstMaximumCompactionCount;
1366 if (maximum_compaction || full_cp == top_cp || interval_ended) {
1367 _maximum_compaction_gc_num = total_invocations();
1368 return sd.region_to_addr(full_cp);
1369 }
1370
1371 const size_t space_live = pointer_delta(new_top, bottom);
1372 const size_t space_used = space->used_in_words();
1373 const size_t space_capacity = space->capacity_in_words();
1374
1375 const double density = double(space_live) / double(space_capacity);
1376 const size_t min_percent_free =
1377 id == perm_space_id ? PermMarkSweepDeadRatio : MarkSweepDeadRatio;
1378 const double limiter = dead_wood_limiter(density, min_percent_free);
1379 const size_t dead_wood_max = space_used - space_live;
1380 const size_t dead_wood_limit = MIN2(size_t(space_capacity * limiter),
1381 dead_wood_max);
1382
1383 if (TraceParallelOldGCDensePrefix) {
1384 tty->print_cr("space_live=" SIZE_FORMAT " " "space_used=" SIZE_FORMAT " "
1385 "space_cap=" SIZE_FORMAT,
1386 space_live, space_used,
1387 space_capacity);
1388 tty->print_cr("dead_wood_limiter(%6.4f, %d)=%6.4f "
1389 "dead_wood_max=" SIZE_FORMAT " dead_wood_limit=" SIZE_FORMAT,
1390 density, min_percent_free, limiter,
1391 dead_wood_max, dead_wood_limit);
1392 }
1393
1394 // Locate the region with the desired amount of dead space to the left.
1395 const RegionData* const limit_cp =
1396 dead_wood_limit_region(full_cp, top_cp, dead_wood_limit);
1397
1398 // Scan from the first region with dead space to the limit region and find the
1399 // one with the best (largest) reclaimed ratio.
1400 double best_ratio = 0.0;
1401 const RegionData* best_cp = full_cp;
1402 for (const RegionData* cp = full_cp; cp < limit_cp; ++cp) {
1403 double tmp_ratio = reclaimed_ratio(cp, bottom, top, new_top);
1404 if (tmp_ratio > best_ratio) {
1405 best_cp = cp;
1406 best_ratio = tmp_ratio;
1407 }
1408 }
1409
1410 #if 0
1411 // Something to consider: if the region with the best ratio is 'close to' the
1412 // first region w/free space, choose the first region with free space
1413 // ("first-free"). The first-free region is usually near the start of the
1414 // heap, which means we are copying most of the heap already, so copy a bit
1415 // more to get complete compaction.
1416 if (pointer_delta(best_cp, full_cp, sizeof(RegionData)) < 4) {
1417 _maximum_compaction_gc_num = total_invocations();
1418 best_cp = full_cp;
1419 }
1420 #endif // #if 0
1421
1422 return sd.region_to_addr(best_cp);
1423 }
1424
1425 #ifndef PRODUCT
1426 void
1427 PSParallelCompact::fill_with_live_objects(SpaceId id, HeapWord* const start,
1428 size_t words)
1429 {
1430 if (TraceParallelOldGCSummaryPhase) {
1431 tty->print_cr("fill_with_live_objects [" PTR_FORMAT " " PTR_FORMAT ") "
1432 SIZE_FORMAT, start, start + words, words);
1433 }
1434
1435 ObjectStartArray* const start_array = _space_info[id].start_array();
1436 CollectedHeap::fill_with_objects(start, words);
1437 for (HeapWord* p = start; p < start + words; p += oop(p)->size()) {
1438 _mark_bitmap.mark_obj(p, words);
1439 _summary_data.add_obj(p, words);
1440 start_array->allocate_block(p);
1441 }
1442 }
1443
1444 void
1445 PSParallelCompact::summarize_new_objects(SpaceId id, HeapWord* start)
1446 {
1447 ParallelCompactData& sd = summary_data();
1448 MutableSpace* space = _space_info[id].space();
1449
1450 // Find the source and destination start addresses.
1451 HeapWord* const src_addr = sd.region_align_down(start);
1452 HeapWord* dst_addr;
1453 if (src_addr < start) {
1454 dst_addr = sd.addr_to_region_ptr(src_addr)->destination();
1455 } else if (src_addr > space->bottom()) {
1456 // The start (the original top() value) is aligned to a region boundary so
1457 // the associated region does not have a destination. Compute the
1458 // destination from the previous region.
1459 RegionData* const cp = sd.addr_to_region_ptr(src_addr) - 1;
1460 dst_addr = cp->destination() + cp->data_size();
1461 } else {
1462 // Filling the entire space.
1463 dst_addr = space->bottom();
1464 }
1465 assert(dst_addr != NULL, "sanity");
1466
1467 // Update the summary data.
1468 bool result = _summary_data.summarize(_space_info[id].split_info(),
1469 src_addr, space->top(), NULL,
1470 dst_addr, space->end(),
1471 _space_info[id].new_top_addr());
1472 assert(result, "should not fail: bad filler object size");
1473 }
1474
1475 void
1476 PSParallelCompact::provoke_split_fill_survivor(SpaceId id)
1477 {
1478 if (total_invocations() % (ParallelOldGCSplitInterval * 3) != 0) {
1479 return;
1480 }
1481
1482 MutableSpace* const space = _space_info[id].space();
1483 if (space->is_empty()) {
1484 HeapWord* b = space->bottom();
1485 HeapWord* t = b + space->capacity_in_words() / 2;
1486 space->set_top(t);
1487 if (ZapUnusedHeapArea) {
1488 space->set_top_for_allocations();
1489 }
1490
1491 size_t min_size = CollectedHeap::min_fill_size();
1492 size_t obj_len = min_size;
1493 while (b + obj_len <= t) {
1494 CollectedHeap::fill_with_object(b, obj_len);
1495 mark_bitmap()->mark_obj(b, obj_len);
1496 summary_data().add_obj(b, obj_len);
1497 b += obj_len;
1498 obj_len = (obj_len & (min_size*3)) + min_size; // 8 16 24 32 8 16 24 32 ...
1499 }
1500 if (b < t) {
1501 // The loop didn't completely fill to t (top); adjust top downward.
1502 space->set_top(b);
1503 if (ZapUnusedHeapArea) {
1504 space->set_top_for_allocations();
1505 }
1506 }
1507
1508 HeapWord** nta = _space_info[id].new_top_addr();
1509 bool result = summary_data().summarize(_space_info[id].split_info(),
1510 space->bottom(), space->top(), NULL,
1511 space->bottom(), space->end(), nta);
1512 assert(result, "space must fit into itself");
1513 }
1514 }
1515
1516 void
1517 PSParallelCompact::provoke_split(bool & max_compaction)
1518 {
1519 if (total_invocations() % ParallelOldGCSplitInterval != 0) {
1520 return;
1521 }
1522
1523 const size_t region_size = ParallelCompactData::RegionSize;
1524 ParallelCompactData& sd = summary_data();
1525
1526 MutableSpace* const eden_space = _space_info[eden_space_id].space();
1527 MutableSpace* const from_space = _space_info[from_space_id].space();
1528 const size_t eden_live = pointer_delta(eden_space->top(),
1529 _space_info[eden_space_id].new_top());
1530 const size_t from_live = pointer_delta(from_space->top(),
1531 _space_info[from_space_id].new_top());
1532
1533 const size_t min_fill_size = CollectedHeap::min_fill_size();
1534 const size_t eden_free = pointer_delta(eden_space->end(), eden_space->top());
1535 const size_t eden_fillable = eden_free >= min_fill_size ? eden_free : 0;
1536 const size_t from_free = pointer_delta(from_space->end(), from_space->top());
1537 const size_t from_fillable = from_free >= min_fill_size ? from_free : 0;
1538
1539 // Choose the space to split; need at least 2 regions live (or fillable).
1540 SpaceId id;
1541 MutableSpace* space;
1542 size_t live_words;
1543 size_t fill_words;
1544 if (eden_live + eden_fillable >= region_size * 2) {
1545 id = eden_space_id;
1546 space = eden_space;
1547 live_words = eden_live;
1548 fill_words = eden_fillable;
1549 } else if (from_live + from_fillable >= region_size * 2) {
1550 id = from_space_id;
1551 space = from_space;
1552 live_words = from_live;
1553 fill_words = from_fillable;
1554 } else {
1555 return; // Give up.
1556 }
1557 assert(fill_words == 0 || fill_words >= min_fill_size, "sanity");
1558
1559 if (live_words < region_size * 2) {
1560 // Fill from top() to end() w/live objects of mixed sizes.
1561 HeapWord* const fill_start = space->top();
1562 live_words += fill_words;
1563
1564 space->set_top(fill_start + fill_words);
1565 if (ZapUnusedHeapArea) {
1566 space->set_top_for_allocations();
1567 }
1568
1569 HeapWord* cur_addr = fill_start;
1570 while (fill_words > 0) {
1571 const size_t r = (size_t)os::random() % (region_size / 2) + min_fill_size;
1572 size_t cur_size = MIN2(align_object_size_(r), fill_words);
1573 if (fill_words - cur_size < min_fill_size) {
1574 cur_size = fill_words; // Avoid leaving a fragment too small to fill.
1575 }
1576
1577 CollectedHeap::fill_with_object(cur_addr, cur_size);
1578 mark_bitmap()->mark_obj(cur_addr, cur_size);
1579 sd.add_obj(cur_addr, cur_size);
1580
1581 cur_addr += cur_size;
1582 fill_words -= cur_size;
1583 }
1584
1585 summarize_new_objects(id, fill_start);
1586 }
1587
1588 max_compaction = false;
1589
1590 // Manipulate the old gen so that it has room for about half of the live data
1591 // in the target young gen space (live_words / 2).
1592 id = old_space_id;
1593 space = _space_info[id].space();
1594 const size_t free_at_end = space->free_in_words();
1595 const size_t free_target = align_object_size(live_words / 2);
1596 const size_t dead = pointer_delta(space->top(), _space_info[id].new_top());
1597
1598 if (free_at_end >= free_target + min_fill_size) {
1599 // Fill space above top() and set the dense prefix so everything survives.
1600 HeapWord* const fill_start = space->top();
1601 const size_t fill_size = free_at_end - free_target;
1602 space->set_top(space->top() + fill_size);
1603 if (ZapUnusedHeapArea) {
1604 space->set_top_for_allocations();
1605 }
1606 fill_with_live_objects(id, fill_start, fill_size);
1607 summarize_new_objects(id, fill_start);
1608 _space_info[id].set_dense_prefix(sd.region_align_down(space->top()));
1609 } else if (dead + free_at_end > free_target) {
1610 // Find a dense prefix that makes the right amount of space available.
1611 HeapWord* cur = sd.region_align_down(space->top());
1612 HeapWord* cur_destination = sd.addr_to_region_ptr(cur)->destination();
1613 size_t dead_to_right = pointer_delta(space->end(), cur_destination);
1614 while (dead_to_right < free_target) {
1615 cur -= region_size;
1616 cur_destination = sd.addr_to_region_ptr(cur)->destination();
1617 dead_to_right = pointer_delta(space->end(), cur_destination);
1618 }
1619 _space_info[id].set_dense_prefix(cur);
1620 }
1621 }
1622 #endif // #ifndef PRODUCT
1623
1624 void PSParallelCompact::summarize_spaces_quick()
1625 {
1626 for (unsigned int i = 0; i < last_space_id; ++i) {
1627 const MutableSpace* space = _space_info[i].space();
1628 HeapWord** nta = _space_info[i].new_top_addr();
1629 bool result = _summary_data.summarize(_space_info[i].split_info(),
1630 space->bottom(), space->top(), NULL,
1631 space->bottom(), space->end(), nta);
1632 assert(result, "space must fit into itself");
1633 _space_info[i].set_dense_prefix(space->bottom());
1634 }
1635
1636 #ifndef PRODUCT
1637 if (ParallelOldGCSplitALot) {
1638 provoke_split_fill_survivor(to_space_id);
1639 }
1640 #endif // #ifndef PRODUCT
1641 }
1642
1643 void PSParallelCompact::fill_dense_prefix_end(SpaceId id)
1644 {
1645 HeapWord* const dense_prefix_end = dense_prefix(id);
1646 const RegionData* region = _summary_data.addr_to_region_ptr(dense_prefix_end);
1647 const idx_t dense_prefix_bit = _mark_bitmap.addr_to_bit(dense_prefix_end);
1648 if (dead_space_crosses_boundary(region, dense_prefix_bit)) {
1649 // Only enough dead space is filled so that any remaining dead space to the
1650 // left is larger than the minimum filler object. (The remainder is filled
1651 // during the copy/update phase.)
1652 //
1653 // The size of the dead space to the right of the boundary is not a
1654 // concern, since compaction will be able to use whatever space is
1655 // available.
1656 //
1657 // Here '||' is the boundary, 'x' represents a don't care bit and a box
1658 // surrounds the space to be filled with an object.
1659 //
1660 // In the 32-bit VM, each bit represents two 32-bit words:
1661 // +---+
1662 // a) beg_bits: ... x x x | 0 | || 0 x x ...
1663 // end_bits: ... x x x | 0 | || 0 x x ...
1664 // +---+
1665 //
1666 // In the 64-bit VM, each bit represents one 64-bit word:
1667 // +------------+
1668 // b) beg_bits: ... x x x | 0 || 0 | x x ...
1669 // end_bits: ... x x 1 | 0 || 0 | x x ...
1670 // +------------+
1671 // +-------+
1672 // c) beg_bits: ... x x | 0 0 | || 0 x x ...
1673 // end_bits: ... x 1 | 0 0 | || 0 x x ...
1674 // +-------+
1675 // +-----------+
1676 // d) beg_bits: ... x | 0 0 0 | || 0 x x ...
1677 // end_bits: ... 1 | 0 0 0 | || 0 x x ...
1678 // +-----------+
1679 // +-------+
1680 // e) beg_bits: ... 0 0 | 0 0 | || 0 x x ...
1681 // end_bits: ... 0 0 | 0 0 | || 0 x x ...
1682 // +-------+
1683
1684 // Initially assume case a, c or e will apply.
1685 size_t obj_len = CollectedHeap::min_fill_size();
1686 HeapWord* obj_beg = dense_prefix_end - obj_len;
1687
1688 #ifdef _LP64
1689 if (MinObjAlignment > 1) { // object alignment > heap word size
1690 // Cases a, c or e.
1691 } else if (_mark_bitmap.is_obj_end(dense_prefix_bit - 2)) {
1692 // Case b above.
1693 obj_beg = dense_prefix_end - 1;
1694 } else if (!_mark_bitmap.is_obj_end(dense_prefix_bit - 3) &&
1695 _mark_bitmap.is_obj_end(dense_prefix_bit - 4)) {
1696 // Case d above.
1697 obj_beg = dense_prefix_end - 3;
1698 obj_len = 3;
1699 }
1700 #endif // #ifdef _LP64
1701
1702 CollectedHeap::fill_with_object(obj_beg, obj_len);
1703 _mark_bitmap.mark_obj(obj_beg, obj_len);
1704 _summary_data.add_obj(obj_beg, obj_len);
1705 assert(start_array(id) != NULL, "sanity");
1706 start_array(id)->allocate_block(obj_beg);
1707 }
1708 }
1709
1710 void
1711 PSParallelCompact::clear_source_region(HeapWord* beg_addr, HeapWord* end_addr)
1712 {
1713 RegionData* const beg_ptr = _summary_data.addr_to_region_ptr(beg_addr);
1714 HeapWord* const end_aligned_up = _summary_data.region_align_up(end_addr);
1715 RegionData* const end_ptr = _summary_data.addr_to_region_ptr(end_aligned_up);
1716 for (RegionData* cur = beg_ptr; cur < end_ptr; ++cur) {
1717 cur->set_source_region(0);
1718 }
1719 }
1720
1721 void
1722 PSParallelCompact::summarize_space(SpaceId id, bool maximum_compaction)
1723 {
1724 assert(id < last_space_id, "id out of range");
1725 assert(_space_info[id].dense_prefix() == _space_info[id].space()->bottom() ||
1726 ParallelOldGCSplitALot && id == old_space_id,
1727 "should have been reset in summarize_spaces_quick()");
1728
1729 const MutableSpace* space = _space_info[id].space();
1730 if (_space_info[id].new_top() != space->bottom()) {
1731 HeapWord* dense_prefix_end = compute_dense_prefix(id, maximum_compaction);
1732 _space_info[id].set_dense_prefix(dense_prefix_end);
1733
1734 #ifndef PRODUCT
1735 if (TraceParallelOldGCDensePrefix) {
1736 print_dense_prefix_stats("ratio", id, maximum_compaction,
1737 dense_prefix_end);
1738 HeapWord* addr = compute_dense_prefix_via_density(id, maximum_compaction);
1739 print_dense_prefix_stats("density", id, maximum_compaction, addr);
1740 }
1741 #endif // #ifndef PRODUCT
1742
1743 // Recompute the summary data, taking into account the dense prefix. If
1744 // every last byte will be reclaimed, then the existing summary data which
1745 // compacts everything can be left in place.
1746 if (!maximum_compaction && dense_prefix_end != space->bottom()) {
1747 // If dead space crosses the dense prefix boundary, it is (at least
1748 // partially) filled with a dummy object, marked live and added to the
1749 // summary data. This simplifies the copy/update phase and must be done
1750 // before the final locations of objects are determined, to prevent
1751 // leaving a fragment of dead space that is too small to fill.
1752 fill_dense_prefix_end(id);
1753
1754 // Compute the destination of each Region, and thus each object.
1755 _summary_data.summarize_dense_prefix(space->bottom(), dense_prefix_end);
1756 _summary_data.summarize(_space_info[id].split_info(),
1757 dense_prefix_end, space->top(), NULL,
1758 dense_prefix_end, space->end(),
1759 _space_info[id].new_top_addr());
1760 }
1761 }
1762
1763 if (TraceParallelOldGCSummaryPhase) {
1764 const size_t region_size = ParallelCompactData::RegionSize;
1765 HeapWord* const dense_prefix_end = _space_info[id].dense_prefix();
1766 const size_t dp_region = _summary_data.addr_to_region_idx(dense_prefix_end);
1767 const size_t dp_words = pointer_delta(dense_prefix_end, space->bottom());
1768 HeapWord* const new_top = _space_info[id].new_top();
1769 const HeapWord* nt_aligned_up = _summary_data.region_align_up(new_top);
1770 const size_t cr_words = pointer_delta(nt_aligned_up, dense_prefix_end);
1771 tty->print_cr("id=%d cap=" SIZE_FORMAT " dp=" PTR_FORMAT " "
1772 "dp_region=" SIZE_FORMAT " " "dp_count=" SIZE_FORMAT " "
1773 "cr_count=" SIZE_FORMAT " " "nt=" PTR_FORMAT,
1774 id, space->capacity_in_words(), dense_prefix_end,
1775 dp_region, dp_words / region_size,
1776 cr_words / region_size, new_top);
1777 }
1778 }
1779
1780 #ifndef PRODUCT
1781 void PSParallelCompact::summary_phase_msg(SpaceId dst_space_id,
1782 HeapWord* dst_beg, HeapWord* dst_end,
1783 SpaceId src_space_id,
1784 HeapWord* src_beg, HeapWord* src_end)
1785 {
1786 if (TraceParallelOldGCSummaryPhase) {
1787 tty->print_cr("summarizing %d [%s] into %d [%s]: "
1788 "src=" PTR_FORMAT "-" PTR_FORMAT " "
1789 SIZE_FORMAT "-" SIZE_FORMAT " "
1790 "dst=" PTR_FORMAT "-" PTR_FORMAT " "
1791 SIZE_FORMAT "-" SIZE_FORMAT,
1792 src_space_id, space_names[src_space_id],
1793 dst_space_id, space_names[dst_space_id],
1794 src_beg, src_end,
1795 _summary_data.addr_to_region_idx(src_beg),
1796 _summary_data.addr_to_region_idx(src_end),
1797 dst_beg, dst_end,
1798 _summary_data.addr_to_region_idx(dst_beg),
1799 _summary_data.addr_to_region_idx(dst_end));
1800 }
1801 }
1802 #endif // #ifndef PRODUCT
1803
1804 void PSParallelCompact::summary_phase(ParCompactionManager* cm,
1805 bool maximum_compaction)
1806 {
1807 EventMark m("2 summarize");
1808 TraceTime tm("summary phase", print_phases(), true, gclog_or_tty);
1809 // trace("2");
1810
1811 #ifdef ASSERT
1812 if (TraceParallelOldGCMarkingPhase) {
1813 tty->print_cr("add_obj_count=" SIZE_FORMAT " "
1814 "add_obj_bytes=" SIZE_FORMAT,
1815 add_obj_count, add_obj_size * HeapWordSize);
1816 tty->print_cr("mark_bitmap_count=" SIZE_FORMAT " "
1817 "mark_bitmap_bytes=" SIZE_FORMAT,
1818 mark_bitmap_count, mark_bitmap_size * HeapWordSize);
1819 }
1820 #endif // #ifdef ASSERT
1821
1822 // Quick summarization of each space into itself, to see how much is live.
1823 summarize_spaces_quick();
1824
1825 if (TraceParallelOldGCSummaryPhase) {
1826 tty->print_cr("summary_phase: after summarizing each space to self");
1827 Universe::print();
1828 NOT_PRODUCT(print_region_ranges());
1829 if (Verbose) {
1830 NOT_PRODUCT(print_initial_summary_data(_summary_data, _space_info));
1831 }
1832 }
1833
1834 // The amount of live data that will end up in old space (assuming it fits).
1835 size_t old_space_total_live = 0;
1836 assert(perm_space_id < old_space_id, "should not count perm data here");
1837 for (unsigned int id = old_space_id; id < last_space_id; ++id) {
1838 old_space_total_live += pointer_delta(_space_info[id].new_top(),
1839 _space_info[id].space()->bottom());
1840 }
1841
1842 MutableSpace* const old_space = _space_info[old_space_id].space();
1843 const size_t old_capacity = old_space->capacity_in_words();
1844 if (old_space_total_live > old_capacity) {
1845 // XXX - should also try to expand
1846 maximum_compaction = true;
1847 }
1848 #ifndef PRODUCT
1849 if (ParallelOldGCSplitALot && old_space_total_live < old_capacity) {
1850 provoke_split(maximum_compaction);
1851 }
1852 #endif // #ifndef PRODUCT
1853
1854 // Permanent and Old generations.
1855 summarize_space(perm_space_id, maximum_compaction);
1856 summarize_space(old_space_id, maximum_compaction);
1857
1858 // Summarize the remaining spaces in the young gen. The initial target space
1859 // is the old gen. If a space does not fit entirely into the target, then the
1860 // remainder is compacted into the space itself and that space becomes the new
1861 // target.
1862 SpaceId dst_space_id = old_space_id;
1863 HeapWord* dst_space_end = old_space->end();
1864 HeapWord** new_top_addr = _space_info[dst_space_id].new_top_addr();
1865 for (unsigned int id = eden_space_id; id < last_space_id; ++id) {
1866 const MutableSpace* space = _space_info[id].space();
1867 const size_t live = pointer_delta(_space_info[id].new_top(),
1868 space->bottom());
1869 const size_t available = pointer_delta(dst_space_end, *new_top_addr);
1870
1871 NOT_PRODUCT(summary_phase_msg(dst_space_id, *new_top_addr, dst_space_end,
1872 SpaceId(id), space->bottom(), space->top());)
1873 if (live > 0 && live <= available) {
1874 // All the live data will fit.
1875 bool done = _summary_data.summarize(_space_info[id].split_info(),
1876 space->bottom(), space->top(),
1877 NULL,
1878 *new_top_addr, dst_space_end,
1879 new_top_addr);
1880 assert(done, "space must fit into old gen");
1881
1882 // Reset the new_top value for the space.
1883 _space_info[id].set_new_top(space->bottom());
1884 } else if (live > 0) {
1885 // Attempt to fit part of the source space into the target space.
1886 HeapWord* next_src_addr = NULL;
1887 bool done = _summary_data.summarize(_space_info[id].split_info(),
1888 space->bottom(), space->top(),
1889 &next_src_addr,
1890 *new_top_addr, dst_space_end,
1891 new_top_addr);
1892 assert(!done, "space should not fit into old gen");
1893 assert(next_src_addr != NULL, "sanity");
1894
1895 // The source space becomes the new target, so the remainder is compacted
1896 // within the space itself.
1897 dst_space_id = SpaceId(id);
1898 dst_space_end = space->end();
1899 new_top_addr = _space_info[id].new_top_addr();
1900 NOT_PRODUCT(summary_phase_msg(dst_space_id,
1901 space->bottom(), dst_space_end,
1902 SpaceId(id), next_src_addr, space->top());)
1903 done = _summary_data.summarize(_space_info[id].split_info(),
1904 next_src_addr, space->top(),
1905 NULL,
1906 space->bottom(), dst_space_end,
1907 new_top_addr);
1908 assert(done, "space must fit when compacted into itself");
1909 assert(*new_top_addr <= space->top(), "usage should not grow");
1910 }
1911 }
1912
1913 if (TraceParallelOldGCSummaryPhase) {
1914 tty->print_cr("summary_phase: after final summarization");
1915 Universe::print();
1916 NOT_PRODUCT(print_region_ranges());
1917 if (Verbose) {
1918 NOT_PRODUCT(print_generic_summary_data(_summary_data, _space_info));
1919 }
1920 }
1921 }
1922
1923 // This method should contain all heap-specific policy for invoking a full
1924 // collection. invoke_no_policy() will only attempt to compact the heap; it
1925 // will do nothing further. If we need to bail out for policy reasons, scavenge
1926 // before full gc, or any other specialized behavior, it needs to be added here.
1927 //
1928 // Note that this method should only be called from the vm_thread while at a
1929 // safepoint.
1930 //
1931 // Note that the all_soft_refs_clear flag in the collector policy
1932 // may be true because this method can be called without intervening
1933 // activity. For example when the heap space is tight and full measure
1934 // are being taken to free space.
1935 void PSParallelCompact::invoke(bool maximum_heap_compaction) {
1936 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
1937 assert(Thread::current() == (Thread*)VMThread::vm_thread(),
1938 "should be in vm thread");
1939
1940 ParallelScavengeHeap* heap = gc_heap();
1941 GCCause::Cause gc_cause = heap->gc_cause();
1942 assert(!heap->is_gc_active(), "not reentrant");
1943
1944 PSAdaptiveSizePolicy* policy = heap->size_policy();
1945 IsGCActiveMark mark;
1946
1947 if (ScavengeBeforeFullGC) {
1948 PSScavenge::invoke_no_policy();
1949 }
1950
1951 const bool clear_all_soft_refs =
1952 heap->collector_policy()->should_clear_all_soft_refs();
1953
1954 PSParallelCompact::invoke_no_policy(clear_all_soft_refs ||
1955 maximum_heap_compaction);
1956 }
1957
1958 bool ParallelCompactData::region_contains(size_t region_index, HeapWord* addr) {
1959 size_t addr_region_index = addr_to_region_idx(addr);
1960 return region_index == addr_region_index;
1961 }
1962
1963 // This method contains no policy. You should probably
1964 // be calling invoke() instead.
1965 void PSParallelCompact::invoke_no_policy(bool maximum_heap_compaction) {
1966 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
1967 assert(ref_processor() != NULL, "Sanity");
1968
1969 if (GC_locker::check_active_before_gc()) {
1970 return;
1971 }
1972
1973 TimeStamp marking_start;
1974 TimeStamp compaction_start;
1975 TimeStamp collection_exit;
1976
1977 ParallelScavengeHeap* heap = gc_heap();
1978 GCCause::Cause gc_cause = heap->gc_cause();
1979 PSYoungGen* young_gen = heap->young_gen();
1980 PSOldGen* old_gen = heap->old_gen();
1981 PSPermGen* perm_gen = heap->perm_gen();
1982 PSAdaptiveSizePolicy* size_policy = heap->size_policy();
1983
1984 // The scope of casr should end after code that can change
1985 // CollectorPolicy::_should_clear_all_soft_refs.
1986 ClearedAllSoftRefs casr(maximum_heap_compaction,
1987 heap->collector_policy());
1988
1989 if (ZapUnusedHeapArea) {
1990 // Save information needed to minimize mangling
1991 heap->record_gen_tops_before_GC();
1992 }
1993
1994 heap->pre_full_gc_dump();
1995
1996 _print_phases = PrintGCDetails && PrintParallelOldGCPhaseTimes;
1997
1998 // Make sure data structures are sane, make the heap parsable, and do other
1999 // miscellaneous bookkeeping.
2000 PreGCValues pre_gc_values;
2001 pre_compact(&pre_gc_values);
2002
2003 // Get the compaction manager reserved for the VM thread.
2004 ParCompactionManager* const vmthread_cm =
2005 ParCompactionManager::manager_array(gc_task_manager()->workers());
2006
2007 // Place after pre_compact() where the number of invocations is incremented.
2008 AdaptiveSizePolicyOutput(size_policy, heap->total_collections());
2009
2010 {
2011 ResourceMark rm;
2012 HandleMark hm;
2013
2014 const bool is_system_gc = gc_cause == GCCause::_java_lang_system_gc;
2015
2016 // This is useful for debugging but don't change the output the
2017 // the customer sees.
2018 const char* gc_cause_str = "Full GC";
2019 if (is_system_gc && PrintGCDetails) {
2020 gc_cause_str = "Full GC (System)";
2021 }
2022 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
2023 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
2024 TraceTime t1(gc_cause_str, PrintGC, !PrintGCDetails, gclog_or_tty);
2025 TraceCollectorStats tcs(counters());
2026 TraceMemoryManagerStats tms(true /* Full GC */);
2027
2028 if (TraceGen1Time) accumulated_time()->start();
2029
2030 // Let the size policy know we're starting
2031 size_policy->major_collection_begin();
2032
2033 // When collecting the permanent generation methodOops may be moving,
2034 // so we either have to flush all bcp data or convert it into bci.
2035 CodeCache::gc_prologue();
2036 Threads::gc_prologue();
2037
2038 NOT_PRODUCT(ref_processor()->verify_no_references_recorded());
2039 COMPILER2_PRESENT(DerivedPointerTable::clear());
2040
2041 ref_processor()->enable_discovery();
2042 ref_processor()->setup_policy(maximum_heap_compaction);
2043
2044 bool marked_for_unloading = false;
2045
2046 marking_start.update();
2047 marking_phase(vmthread_cm, maximum_heap_compaction);
2048
2049 #ifndef PRODUCT
2050 if (TraceParallelOldGCMarkingPhase) {
2051 gclog_or_tty->print_cr("marking_phase: cas_tries %d cas_retries %d "
2052 "cas_by_another %d",
2053 mark_bitmap()->cas_tries(), mark_bitmap()->cas_retries(),
2054 mark_bitmap()->cas_by_another());
2055 }
2056 #endif // #ifndef PRODUCT
2057
2058 bool max_on_system_gc = UseMaximumCompactionOnSystemGC && is_system_gc;
2059 summary_phase(vmthread_cm, maximum_heap_compaction || max_on_system_gc);
2060
2061 COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity"));
2062 COMPILER2_PRESENT(DerivedPointerTable::set_active(false));
2063
2064 // adjust_roots() updates Universe::_intArrayKlassObj which is
2065 // needed by the compaction for filling holes in the dense prefix.
2066 adjust_roots();
2067
2068 compaction_start.update();
2069 // Does the perm gen always have to be done serially because
2070 // klasses are used in the update of an object?
2071 compact_perm(vmthread_cm);
2072
2073 if (UseParallelOldGCCompacting) {
2074 compact();
2075 } else {
2076 compact_serial(vmthread_cm);
2077 }
2078
2079 // Reset the mark bitmap, summary data, and do other bookkeeping. Must be
2080 // done before resizing.
2081 post_compact();
2082
2083 // Let the size policy know we're done
2084 size_policy->major_collection_end(old_gen->used_in_bytes(), gc_cause);
2085
2086 if (UseAdaptiveSizePolicy) {
2087 if (PrintAdaptiveSizePolicy) {
2088 gclog_or_tty->print("AdaptiveSizeStart: ");
2089 gclog_or_tty->stamp();
2090 gclog_or_tty->print_cr(" collection: %d ",
2091 heap->total_collections());
2092 if (Verbose) {
2093 gclog_or_tty->print("old_gen_capacity: %d young_gen_capacity: %d"
2094 " perm_gen_capacity: %d ",
2095 old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes(),
2096 perm_gen->capacity_in_bytes());
2097 }
2098 }
2099
2100 // Don't check if the size_policy is ready here. Let
2101 // the size_policy check that internally.
2102 if (UseAdaptiveGenerationSizePolicyAtMajorCollection &&
2103 ((gc_cause != GCCause::_java_lang_system_gc) ||
2104 UseAdaptiveSizePolicyWithSystemGC)) {
2105 // Calculate optimal free space amounts
2106 assert(young_gen->max_size() >
2107 young_gen->from_space()->capacity_in_bytes() +
2108 young_gen->to_space()->capacity_in_bytes(),
2109 "Sizes of space in young gen are out-of-bounds");
2110 size_t max_eden_size = young_gen->max_size() -
2111 young_gen->from_space()->capacity_in_bytes() -
2112 young_gen->to_space()->capacity_in_bytes();
2113 size_policy->compute_generation_free_space(
2114 young_gen->used_in_bytes(),
2115 young_gen->eden_space()->used_in_bytes(),
2116 old_gen->used_in_bytes(),
2117 perm_gen->used_in_bytes(),
2118 young_gen->eden_space()->capacity_in_bytes(),
2119 old_gen->max_gen_size(),
2120 max_eden_size,
2121 true /* full gc*/,
2122 gc_cause,
2123 heap->collector_policy());
2124
2125 heap->resize_old_gen(
2126 size_policy->calculated_old_free_size_in_bytes());
2127
2128 // Don't resize the young generation at an major collection. A
2129 // desired young generation size may have been calculated but
2130 // resizing the young generation complicates the code because the
2131 // resizing of the old generation may have moved the boundary
2132 // between the young generation and the old generation. Let the
2133 // young generation resizing happen at the minor collections.
2134 }
2135 if (PrintAdaptiveSizePolicy) {
2136 gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ",
2137 heap->total_collections());
2138 }
2139 }
2140
2141 if (UsePerfData) {
2142 PSGCAdaptivePolicyCounters* const counters = heap->gc_policy_counters();
2143 counters->update_counters();
2144 counters->update_old_capacity(old_gen->capacity_in_bytes());
2145 counters->update_young_capacity(young_gen->capacity_in_bytes());
2146 }
2147
2148 heap->resize_all_tlabs();
2149
2150 // We collected the perm gen, so we'll resize it here.
2151 perm_gen->compute_new_size(pre_gc_values.perm_gen_used());
2152
2153 if (TraceGen1Time) accumulated_time()->stop();
2154
2155 if (PrintGC) {
2156 if (PrintGCDetails) {
2157 // No GC timestamp here. This is after GC so it would be confusing.
2158 young_gen->print_used_change(pre_gc_values.young_gen_used());
2159 old_gen->print_used_change(pre_gc_values.old_gen_used());
2160 heap->print_heap_change(pre_gc_values.heap_used());
2161 // Print perm gen last (print_heap_change() excludes the perm gen).
2162 perm_gen->print_used_change(pre_gc_values.perm_gen_used());
2163 } else {
2164 heap->print_heap_change(pre_gc_values.heap_used());
2165 }
2166 }
2167
2168 // Track memory usage and detect low memory
2169 MemoryService::track_memory_usage();
2170 heap->update_counters();
2171 }
2172
2173 #ifdef ASSERT
2174 for (size_t i = 0; i < ParallelGCThreads + 1; ++i) {
2175 ParCompactionManager* const cm =
2176 ParCompactionManager::manager_array(int(i));
2177 assert(cm->marking_stack()->is_empty(), "should be empty");
2178 assert(cm->region_stack()->is_empty(), "should be empty");
2179 assert(cm->revisit_klass_stack()->is_empty(), "should be empty");
2180 }
2181 #endif // ASSERT
2182
2183 if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) {
2184 HandleMark hm; // Discard invalid handles created during verification
2185 gclog_or_tty->print(" VerifyAfterGC:");
2186 Universe::verify(false);
2187 }
2188
2189 // Re-verify object start arrays
2190 if (VerifyObjectStartArray &&
2191 VerifyAfterGC) {
2192 old_gen->verify_object_start_array();
2193 perm_gen->verify_object_start_array();
2194 }
2195
2196 if (ZapUnusedHeapArea) {
2197 old_gen->object_space()->check_mangled_unused_area_complete();
2198 perm_gen->object_space()->check_mangled_unused_area_complete();
2199 }
2200
2201 NOT_PRODUCT(ref_processor()->verify_no_references_recorded());
2202
2203 collection_exit.update();
2204
2205 if (PrintHeapAtGC) {
2206 Universe::print_heap_after_gc();
2207 }
2208 if (PrintGCTaskTimeStamps) {
2209 gclog_or_tty->print_cr("VM-Thread " INT64_FORMAT " " INT64_FORMAT " "
2210 INT64_FORMAT,
2211 marking_start.ticks(), compaction_start.ticks(),
2212 collection_exit.ticks());
2213 gc_task_manager()->print_task_time_stamps();
2214 }
2215
2216 heap->post_full_gc_dump();
2217
2218 #ifdef TRACESPINNING
2219 ParallelTaskTerminator::print_termination_counts();
2220 #endif
2221 }
2222
2223 bool PSParallelCompact::absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy,
2224 PSYoungGen* young_gen,
2225 PSOldGen* old_gen) {
2226 MutableSpace* const eden_space = young_gen->eden_space();
2227 assert(!eden_space->is_empty(), "eden must be non-empty");
2228 assert(young_gen->virtual_space()->alignment() ==
2229 old_gen->virtual_space()->alignment(), "alignments do not match");
2230
2231 if (!(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary)) {
2232 return false;
2233 }
2234
2235 // Both generations must be completely committed.
2236 if (young_gen->virtual_space()->uncommitted_size() != 0) {
2237 return false;
2238 }
2239 if (old_gen->virtual_space()->uncommitted_size() != 0) {
2240 return false;
2241 }
2242
2243 // Figure out how much to take from eden. Include the average amount promoted
2244 // in the total; otherwise the next young gen GC will simply bail out to a
2245 // full GC.
2246 const size_t alignment = old_gen->virtual_space()->alignment();
2247 const size_t eden_used = eden_space->used_in_bytes();
2248 const size_t promoted = (size_t)size_policy->avg_promoted()->padded_average();
2249 const size_t absorb_size = align_size_up(eden_used + promoted, alignment);
2250 const size_t eden_capacity = eden_space->capacity_in_bytes();
2251
2252 if (absorb_size >= eden_capacity) {
2253 return false; // Must leave some space in eden.
2254 }
2255
2256 const size_t new_young_size = young_gen->capacity_in_bytes() - absorb_size;
2257 if (new_young_size < young_gen->min_gen_size()) {
2258 return false; // Respect young gen minimum size.
2259 }
2260
2261 if (TraceAdaptiveGCBoundary && Verbose) {
2262 gclog_or_tty->print(" absorbing " SIZE_FORMAT "K: "
2263 "eden " SIZE_FORMAT "K->" SIZE_FORMAT "K "
2264 "from " SIZE_FORMAT "K, to " SIZE_FORMAT "K "
2265 "young_gen " SIZE_FORMAT "K->" SIZE_FORMAT "K ",
2266 absorb_size / K,
2267 eden_capacity / K, (eden_capacity - absorb_size) / K,
2268 young_gen->from_space()->used_in_bytes() / K,
2269 young_gen->to_space()->used_in_bytes() / K,
2270 young_gen->capacity_in_bytes() / K, new_young_size / K);
2271 }
2272
2273 // Fill the unused part of the old gen.
2274 MutableSpace* const old_space = old_gen->object_space();
2275 HeapWord* const unused_start = old_space->top();
2276 size_t const unused_words = pointer_delta(old_space->end(), unused_start);
2277
2278 if (unused_words > 0) {
2279 if (unused_words < CollectedHeap::min_fill_size()) {
2280 return false; // If the old gen cannot be filled, must give up.
2281 }
2282 CollectedHeap::fill_with_objects(unused_start, unused_words);
2283 }
2284
2285 // Take the live data from eden and set both top and end in the old gen to
2286 // eden top. (Need to set end because reset_after_change() mangles the region
2287 // from end to virtual_space->high() in debug builds).
2288 HeapWord* const new_top = eden_space->top();
2289 old_gen->virtual_space()->expand_into(young_gen->virtual_space(),
2290 absorb_size);
2291 young_gen->reset_after_change();
2292 old_space->set_top(new_top);
2293 old_space->set_end(new_top);
2294 old_gen->reset_after_change();
2295
2296 // Update the object start array for the filler object and the data from eden.
2297 ObjectStartArray* const start_array = old_gen->start_array();
2298 for (HeapWord* p = unused_start; p < new_top; p += oop(p)->size()) {
2299 start_array->allocate_block(p);
2300 }
2301
2302 // Could update the promoted average here, but it is not typically updated at
2303 // full GCs and the value to use is unclear. Something like
2304 //
2305 // cur_promoted_avg + absorb_size / number_of_scavenges_since_last_full_gc.
2306
2307 size_policy->set_bytes_absorbed_from_eden(absorb_size);
2308 return true;
2309 }
2310
2311 GCTaskManager* const PSParallelCompact::gc_task_manager() {
2312 assert(ParallelScavengeHeap::gc_task_manager() != NULL,
2313 "shouldn't return NULL");
2314 return ParallelScavengeHeap::gc_task_manager();
2315 }
2316
2317 void PSParallelCompact::marking_phase(ParCompactionManager* cm,
2318 bool maximum_heap_compaction) {
2319 // Recursively traverse all live objects and mark them
2320 EventMark m("1 mark object");
2321 TraceTime tm("marking phase", print_phases(), true, gclog_or_tty);
2322
2323 ParallelScavengeHeap* heap = gc_heap();
2324 uint parallel_gc_threads = heap->gc_task_manager()->workers();
2325 TaskQueueSetSuper* qset = ParCompactionManager::region_array();
2326 ParallelTaskTerminator terminator(parallel_gc_threads, qset);
2327
2328 PSParallelCompact::MarkAndPushClosure mark_and_push_closure(cm);
2329 PSParallelCompact::FollowStackClosure follow_stack_closure(cm);
2330
2331 {
2332 TraceTime tm_m("par mark", print_phases(), true, gclog_or_tty);
2333 ParallelScavengeHeap::ParStrongRootsScope psrs;
2334
2335 GCTaskQueue* q = GCTaskQueue::create();
2336
2337 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::universe));
2338 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::jni_handles));
2339 // We scan the thread roots in parallel
2340 Threads::create_thread_roots_marking_tasks(q);
2341 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::object_synchronizer));
2342 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::flat_profiler));
2343 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::management));
2344 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::system_dictionary));
2345 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::jvmti));
2346 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::vm_symbols));
2347 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::code_cache));
2348
2349 if (parallel_gc_threads > 1) {
2350 for (uint j = 0; j < parallel_gc_threads; j++) {
2351 q->enqueue(new StealMarkingTask(&terminator));
2352 }
2353 }
2354
2355 WaitForBarrierGCTask* fin = WaitForBarrierGCTask::create();
2356 q->enqueue(fin);
2357
2358 gc_task_manager()->add_list(q);
2359
2360 fin->wait_for();
2361
2362 // We have to release the barrier tasks!
2363 WaitForBarrierGCTask::destroy(fin);
2364 }
2365
2366 // Process reference objects found during marking
2367 {
2368 TraceTime tm_r("reference processing", print_phases(), true, gclog_or_tty);
2369 if (ref_processor()->processing_is_mt()) {
2370 RefProcTaskExecutor task_executor;
2371 ref_processor()->process_discovered_references(
2372 is_alive_closure(), &mark_and_push_closure, &follow_stack_closure,
2373 &task_executor);
2374 } else {
2375 ref_processor()->process_discovered_references(
2376 is_alive_closure(), &mark_and_push_closure, &follow_stack_closure, NULL);
2377 }
2378 }
2379
2380 TraceTime tm_c("class unloading", print_phases(), true, gclog_or_tty);
2381 // Follow system dictionary roots and unload classes.
2382 bool purged_class = SystemDictionary::do_unloading(is_alive_closure());
2383
2384 // Follow code cache roots.
2385 CodeCache::do_unloading(is_alive_closure(), &mark_and_push_closure,
2386 purged_class);
2387 cm->follow_marking_stacks(); // Flush marking stack.
2388
2389 // Update subklass/sibling/implementor links of live klasses
2390 // revisit_klass_stack is used in follow_weak_klass_links().
2391 follow_weak_klass_links();
2392
2393 // Revisit memoized MDO's and clear any unmarked weak refs
2394 follow_mdo_weak_refs();
2395
2396 // Visit symbol and interned string tables and delete unmarked oops
2397 SymbolTable::unlink(is_alive_closure());
2398 StringTable::unlink(is_alive_closure());
2399
2400 assert(cm->marking_stacks_empty(), "marking stacks should be empty");
2401 }
2402
2403 // This should be moved to the shared markSweep code!
2404 class PSAlwaysTrueClosure: public BoolObjectClosure {
2405 public:
2406 void do_object(oop p) { ShouldNotReachHere(); }
2407 bool do_object_b(oop p) { return true; }
2408 };
2409 static PSAlwaysTrueClosure always_true;
2410
2411 void PSParallelCompact::adjust_roots() {
2412 // Adjust the pointers to reflect the new locations
2413 EventMark m("3 adjust roots");
2414 TraceTime tm("adjust roots", print_phases(), true, gclog_or_tty);
2415
2416 // General strong roots.
2417 Universe::oops_do(adjust_root_pointer_closure());
2418 ReferenceProcessor::oops_do(adjust_root_pointer_closure());
2419 JNIHandles::oops_do(adjust_root_pointer_closure()); // Global (strong) JNI handles
2420 Threads::oops_do(adjust_root_pointer_closure(), NULL);
2421 ObjectSynchronizer::oops_do(adjust_root_pointer_closure());
2422 FlatProfiler::oops_do(adjust_root_pointer_closure());
2423 Management::oops_do(adjust_root_pointer_closure());
2424 JvmtiExport::oops_do(adjust_root_pointer_closure());
2425 // SO_AllClasses
2426 SystemDictionary::oops_do(adjust_root_pointer_closure());
2427 vmSymbols::oops_do(adjust_root_pointer_closure());
2428
2429 // Now adjust pointers in remaining weak roots. (All of which should
2430 // have been cleared if they pointed to non-surviving objects.)
2431 // Global (weak) JNI handles
2432 JNIHandles::weak_oops_do(&always_true, adjust_root_pointer_closure());
2433
2434 CodeCache::oops_do(adjust_pointer_closure());
2435 SymbolTable::oops_do(adjust_root_pointer_closure());
2436 StringTable::oops_do(adjust_root_pointer_closure());
2437 ref_processor()->weak_oops_do(adjust_root_pointer_closure());
2438 // Roots were visited so references into the young gen in roots
2439 // may have been scanned. Process them also.
2440 // Should the reference processor have a span that excludes
2441 // young gen objects?
2442 PSScavenge::reference_processor()->weak_oops_do(
2443 adjust_root_pointer_closure());
2444 }
2445
2446 void PSParallelCompact::compact_perm(ParCompactionManager* cm) {
2447 EventMark m("4 compact perm");
2448 TraceTime tm("compact perm gen", print_phases(), true, gclog_or_tty);
2449 // trace("4");
2450
2451 gc_heap()->perm_gen()->start_array()->reset();
2452 move_and_update(cm, perm_space_id);
2453 }
2454
2455 void PSParallelCompact::enqueue_region_draining_tasks(GCTaskQueue* q,
2456 uint parallel_gc_threads)
2457 {
2458 TraceTime tm("drain task setup", print_phases(), true, gclog_or_tty);
2459
2460 const unsigned int task_count = MAX2(parallel_gc_threads, 1U);
2461 for (unsigned int j = 0; j < task_count; j++) {
2462 q->enqueue(new DrainStacksCompactionTask(j));
2463 }
2464
2465 // Find all regions that are available (can be filled immediately) and
2466 // distribute them to the thread stacks. The iteration is done in reverse
2467 // order (high to low) so the regions will be removed in ascending order.
2468
2469 const ParallelCompactData& sd = PSParallelCompact::summary_data();
2470
2471 size_t fillable_regions = 0; // A count for diagnostic purposes.
2472 unsigned int which = 0; // The worker thread number.
2473
2474 for (unsigned int id = to_space_id; id > perm_space_id; --id) {
2475 SpaceInfo* const space_info = _space_info + id;
2476 MutableSpace* const space = space_info->space();
2477 HeapWord* const new_top = space_info->new_top();
2478
2479 const size_t beg_region = sd.addr_to_region_idx(space_info->dense_prefix());
2480 const size_t end_region =
2481 sd.addr_to_region_idx(sd.region_align_up(new_top));
2482 assert(end_region > 0, "perm gen cannot be empty");
2483
2484 for (size_t cur = end_region - 1; cur >= beg_region; --cur) {
2485 if (sd.region(cur)->claim_unsafe()) {
2486 ParCompactionManager* cm = ParCompactionManager::manager_array(which);
2487 cm->push_region(cur);
2488
2489 if (TraceParallelOldGCCompactionPhase && Verbose) {
2490 const size_t count_mod_8 = fillable_regions & 7;
2491 if (count_mod_8 == 0) gclog_or_tty->print("fillable: ");
2492 gclog_or_tty->print(" " SIZE_FORMAT_W(7), cur);
2493 if (count_mod_8 == 7) gclog_or_tty->cr();
2494 }
2495
2496 NOT_PRODUCT(++fillable_regions;)
2497
2498 // Assign regions to threads in round-robin fashion.
2499 if (++which == task_count) {
2500 which = 0;
2501 }
2502 }
2503 }
2504 }
2505
2506 if (TraceParallelOldGCCompactionPhase) {
2507 if (Verbose && (fillable_regions & 7) != 0) gclog_or_tty->cr();
2508 gclog_or_tty->print_cr("%u initially fillable regions", fillable_regions);
2509 }
2510 }
2511
2512 #define PAR_OLD_DENSE_PREFIX_OVER_PARTITIONING 4
2513
2514 void PSParallelCompact::enqueue_dense_prefix_tasks(GCTaskQueue* q,
2515 uint parallel_gc_threads) {
2516 TraceTime tm("dense prefix task setup", print_phases(), true, gclog_or_tty);
2517
2518 ParallelCompactData& sd = PSParallelCompact::summary_data();
2519
2520 // Iterate over all the spaces adding tasks for updating
2521 // regions in the dense prefix. Assume that 1 gc thread
2522 // will work on opening the gaps and the remaining gc threads
2523 // will work on the dense prefix.
2524 unsigned int space_id;
2525 for (space_id = old_space_id; space_id < last_space_id; ++ space_id) {
2526 HeapWord* const dense_prefix_end = _space_info[space_id].dense_prefix();
2527 const MutableSpace* const space = _space_info[space_id].space();
2528
2529 if (dense_prefix_end == space->bottom()) {
2530 // There is no dense prefix for this space.
2531 continue;
2532 }
2533
2534 // The dense prefix is before this region.
2535 size_t region_index_end_dense_prefix =
2536 sd.addr_to_region_idx(dense_prefix_end);
2537 RegionData* const dense_prefix_cp =
2538 sd.region(region_index_end_dense_prefix);
2539 assert(dense_prefix_end == space->end() ||
2540 dense_prefix_cp->available() ||
2541 dense_prefix_cp->claimed(),
2542 "The region after the dense prefix should always be ready to fill");
2543
2544 size_t region_index_start = sd.addr_to_region_idx(space->bottom());
2545
2546 // Is there dense prefix work?
2547 size_t total_dense_prefix_regions =
2548 region_index_end_dense_prefix - region_index_start;
2549 // How many regions of the dense prefix should be given to
2550 // each thread?
2551 if (total_dense_prefix_regions > 0) {
2552 uint tasks_for_dense_prefix = 1;
2553 if (UseParallelDensePrefixUpdate) {
2554 if (total_dense_prefix_regions <=
2555 (parallel_gc_threads * PAR_OLD_DENSE_PREFIX_OVER_PARTITIONING)) {
2556 // Don't over partition. This assumes that
2557 // PAR_OLD_DENSE_PREFIX_OVER_PARTITIONING is a small integer value
2558 // so there are not many regions to process.
2559 tasks_for_dense_prefix = parallel_gc_threads;
2560 } else {
2561 // Over partition
2562 tasks_for_dense_prefix = parallel_gc_threads *
2563 PAR_OLD_DENSE_PREFIX_OVER_PARTITIONING;
2564 }
2565 }
2566 size_t regions_per_thread = total_dense_prefix_regions /
2567 tasks_for_dense_prefix;
2568 // Give each thread at least 1 region.
2569 if (regions_per_thread == 0) {
2570 regions_per_thread = 1;
2571 }
2572
2573 for (uint k = 0; k < tasks_for_dense_prefix; k++) {
2574 if (region_index_start >= region_index_end_dense_prefix) {
2575 break;
2576 }
2577 // region_index_end is not processed
2578 size_t region_index_end = MIN2(region_index_start + regions_per_thread,
2579 region_index_end_dense_prefix);
2580 q->enqueue(new UpdateDensePrefixTask(SpaceId(space_id),
2581 region_index_start,
2582 region_index_end));
2583 region_index_start = region_index_end;
2584 }
2585 }
2586 // This gets any part of the dense prefix that did not
2587 // fit evenly.
2588 if (region_index_start < region_index_end_dense_prefix) {
2589 q->enqueue(new UpdateDensePrefixTask(SpaceId(space_id),
2590 region_index_start,
2591 region_index_end_dense_prefix));
2592 }
2593 }
2594 }
2595
2596 void PSParallelCompact::enqueue_region_stealing_tasks(
2597 GCTaskQueue* q,
2598 ParallelTaskTerminator* terminator_ptr,
2599 uint parallel_gc_threads) {
2600 TraceTime tm("steal task setup", print_phases(), true, gclog_or_tty);
2601
2602 // Once a thread has drained it's stack, it should try to steal regions from
2603 // other threads.
2604 if (parallel_gc_threads > 1) {
2605 for (uint j = 0; j < parallel_gc_threads; j++) {
2606 q->enqueue(new StealRegionCompactionTask(terminator_ptr));
2607 }
2608 }
2609 }
2610
2611 void PSParallelCompact::compact() {
2612 EventMark m("5 compact");
2613 // trace("5");
2614 TraceTime tm("compaction phase", print_phases(), true, gclog_or_tty);
2615
2616 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
2617 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
2618 PSOldGen* old_gen = heap->old_gen();
2619 old_gen->start_array()->reset();
2620 uint parallel_gc_threads = heap->gc_task_manager()->workers();
2621 TaskQueueSetSuper* qset = ParCompactionManager::region_array();
2622 ParallelTaskTerminator terminator(parallel_gc_threads, qset);
2623
2624 GCTaskQueue* q = GCTaskQueue::create();
2625 enqueue_region_draining_tasks(q, parallel_gc_threads);
2626 enqueue_dense_prefix_tasks(q, parallel_gc_threads);
2627 enqueue_region_stealing_tasks(q, &terminator, parallel_gc_threads);
2628
2629 {
2630 TraceTime tm_pc("par compact", print_phases(), true, gclog_or_tty);
2631
2632 WaitForBarrierGCTask* fin = WaitForBarrierGCTask::create();
2633 q->enqueue(fin);
2634
2635 gc_task_manager()->add_list(q);
2636
2637 fin->wait_for();
2638
2639 // We have to release the barrier tasks!
2640 WaitForBarrierGCTask::destroy(fin);
2641
2642 #ifdef ASSERT
2643 // Verify that all regions have been processed before the deferred updates.
2644 // Note that perm_space_id is skipped; this type of verification is not
2645 // valid until the perm gen is compacted by regions.
2646 for (unsigned int id = old_space_id; id < last_space_id; ++id) {
2647 verify_complete(SpaceId(id));
2648 }
2649 #endif
2650 }
2651
2652 {
2653 // Update the deferred objects, if any. Any compaction manager can be used.
2654 TraceTime tm_du("deferred updates", print_phases(), true, gclog_or_tty);
2655 ParCompactionManager* cm = ParCompactionManager::manager_array(0);
2656 for (unsigned int id = old_space_id; id < last_space_id; ++id) {
2657 update_deferred_objects(cm, SpaceId(id));
2658 }
2659 }
2660 }
2661
2662 #ifdef ASSERT
2663 void PSParallelCompact::verify_complete(SpaceId space_id) {
2664 // All Regions between space bottom() to new_top() should be marked as filled
2665 // and all Regions between new_top() and top() should be available (i.e.,
2666 // should have been emptied).
2667 ParallelCompactData& sd = summary_data();
2668 SpaceInfo si = _space_info[space_id];
2669 HeapWord* new_top_addr = sd.region_align_up(si.new_top());
2670 HeapWord* old_top_addr = sd.region_align_up(si.space()->top());
2671 const size_t beg_region = sd.addr_to_region_idx(si.space()->bottom());
2672 const size_t new_top_region = sd.addr_to_region_idx(new_top_addr);
2673 const size_t old_top_region = sd.addr_to_region_idx(old_top_addr);
2674
2675 bool issued_a_warning = false;
2676
2677 size_t cur_region;
2678 for (cur_region = beg_region; cur_region < new_top_region; ++cur_region) {
2679 const RegionData* const c = sd.region(cur_region);
2680 if (!c->completed()) {
2681 warning("region " SIZE_FORMAT " not filled: "
2682 "destination_count=" SIZE_FORMAT,
2683 cur_region, c->destination_count());
2684 issued_a_warning = true;
2685 }
2686 }
2687
2688 for (cur_region = new_top_region; cur_region < old_top_region; ++cur_region) {
2689 const RegionData* const c = sd.region(cur_region);
2690 if (!c->available()) {
2691 warning("region " SIZE_FORMAT " not empty: "
2692 "destination_count=" SIZE_FORMAT,
2693 cur_region, c->destination_count());
2694 issued_a_warning = true;
2695 }
2696 }
2697
2698 if (issued_a_warning) {
2699 print_region_ranges();
2700 }
2701 }
2702 #endif // #ifdef ASSERT
2703
2704 void PSParallelCompact::compact_serial(ParCompactionManager* cm) {
2705 EventMark m("5 compact serial");
2706 TraceTime tm("compact serial", print_phases(), true, gclog_or_tty);
2707
2708 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
2709 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
2710
2711 PSYoungGen* young_gen = heap->young_gen();
2712 PSOldGen* old_gen = heap->old_gen();
2713
2714 old_gen->start_array()->reset();
2715 old_gen->move_and_update(cm);
2716 young_gen->move_and_update(cm);
2717 }
2718
2719 void
2720 PSParallelCompact::follow_weak_klass_links() {
2721 // All klasses on the revisit stack are marked at this point.
2722 // Update and follow all subklass, sibling and implementor links.
2723 if (PrintRevisitStats) {
2724 gclog_or_tty->print_cr("#classes in system dictionary = %d",
2725 SystemDictionary::number_of_classes());
2726 }
2727 for (uint i = 0; i < ParallelGCThreads + 1; i++) {
2728 ParCompactionManager* cm = ParCompactionManager::manager_array(i);
2729 KeepAliveClosure keep_alive_closure(cm);
2730 Stack<Klass*>* const rks = cm->revisit_klass_stack();
2731 if (PrintRevisitStats) {
2732 gclog_or_tty->print_cr("Revisit klass stack[%u] length = " SIZE_FORMAT,
2733 i, rks->size());
2734 }
2735 while (!rks->is_empty()) {
2736 Klass* const k = rks->pop();
2737 k->follow_weak_klass_links(is_alive_closure(), &keep_alive_closure);
2738 }
2739
2740 cm->follow_marking_stacks();
2741 }
2742 }
2743
2744 void
2745 PSParallelCompact::revisit_weak_klass_link(ParCompactionManager* cm, Klass* k) {
2746 cm->revisit_klass_stack()->push(k);
2747 }
2748
2749 void PSParallelCompact::revisit_mdo(ParCompactionManager* cm, DataLayout* p) {
2750 cm->revisit_mdo_stack()->push(p);
2751 }
2752
2753 void PSParallelCompact::follow_mdo_weak_refs() {
2754 // All strongly reachable oops have been marked at this point;
2755 // we can visit and clear any weak references from MDO's which
2756 // we memoized during the strong marking phase.
2757 if (PrintRevisitStats) {
2758 gclog_or_tty->print_cr("#classes in system dictionary = %d",
2759 SystemDictionary::number_of_classes());
2760 }
2761 for (uint i = 0; i < ParallelGCThreads + 1; i++) {
2762 ParCompactionManager* cm = ParCompactionManager::manager_array(i);
2763 Stack<DataLayout*>* rms = cm->revisit_mdo_stack();
2764 if (PrintRevisitStats) {
2765 gclog_or_tty->print_cr("Revisit MDO stack[%u] size = " SIZE_FORMAT,
2766 i, rms->size());
2767 }
2768 while (!rms->is_empty()) {
2769 rms->pop()->follow_weak_refs(is_alive_closure());
2770 }
2771
2772 cm->follow_marking_stacks();
2773 }
2774 }
2775
2776
2777 #ifdef VALIDATE_MARK_SWEEP
2778
2779 void PSParallelCompact::track_adjusted_pointer(void* p, bool isroot) {
2780 if (!ValidateMarkSweep)
2781 return;
2782
2783 if (!isroot) {
2784 if (_pointer_tracking) {
2785 guarantee(_adjusted_pointers->contains(p), "should have seen this pointer");
2786 _adjusted_pointers->remove(p);
2787 }
2788 } else {
2789 ptrdiff_t index = _root_refs_stack->find(p);
2790 if (index != -1) {
2791 int l = _root_refs_stack->length();
2792 if (l > 0 && l - 1 != index) {
2793 void* last = _root_refs_stack->pop();
2794 assert(last != p, "should be different");
2795 _root_refs_stack->at_put(index, last);
2796 } else {
2797 _root_refs_stack->remove(p);
2798 }
2799 }
2800 }
2801 }
2802
2803
2804 void PSParallelCompact::check_adjust_pointer(void* p) {
2805 _adjusted_pointers->push(p);
2806 }
2807
2808
2809 class AdjusterTracker: public OopClosure {
2810 public:
2811 AdjusterTracker() {};
2812 void do_oop(oop* o) { PSParallelCompact::check_adjust_pointer(o); }
2813 void do_oop(narrowOop* o) { PSParallelCompact::check_adjust_pointer(o); }
2814 };
2815
2816
2817 void PSParallelCompact::track_interior_pointers(oop obj) {
2818 if (ValidateMarkSweep) {
2819 _adjusted_pointers->clear();
2820 _pointer_tracking = true;
2821
2822 AdjusterTracker checker;
2823 obj->oop_iterate(&checker);
2824 }
2825 }
2826
2827
2828 void PSParallelCompact::check_interior_pointers() {
2829 if (ValidateMarkSweep) {
2830 _pointer_tracking = false;
2831 guarantee(_adjusted_pointers->length() == 0, "should have processed the same pointers");
2832 }
2833 }
2834
2835
2836 void PSParallelCompact::reset_live_oop_tracking(bool at_perm) {
2837 if (ValidateMarkSweep) {
2838 guarantee((size_t)_live_oops->length() == _live_oops_index, "should be at end of live oops");
2839 _live_oops_index = at_perm ? _live_oops_index_at_perm : 0;
2840 }
2841 }
2842
2843
2844 void PSParallelCompact::register_live_oop(oop p, size_t size) {
2845 if (ValidateMarkSweep) {
2846 _live_oops->push(p);
2847 _live_oops_size->push(size);
2848 _live_oops_index++;
2849 }
2850 }
2851
2852 void PSParallelCompact::validate_live_oop(oop p, size_t size) {
2853 if (ValidateMarkSweep) {
2854 oop obj = _live_oops->at((int)_live_oops_index);
2855 guarantee(obj == p, "should be the same object");
2856 guarantee(_live_oops_size->at((int)_live_oops_index) == size, "should be the same size");
2857 _live_oops_index++;
2858 }
2859 }
2860
2861 void PSParallelCompact::live_oop_moved_to(HeapWord* q, size_t size,
2862 HeapWord* compaction_top) {
2863 assert(oop(q)->forwardee() == NULL || oop(q)->forwardee() == oop(compaction_top),
2864 "should be moved to forwarded location");
2865 if (ValidateMarkSweep) {
2866 PSParallelCompact::validate_live_oop(oop(q), size);
2867 _live_oops_moved_to->push(oop(compaction_top));
2868 }
2869 if (RecordMarkSweepCompaction) {
2870 _cur_gc_live_oops->push(q);
2871 _cur_gc_live_oops_moved_to->push(compaction_top);
2872 _cur_gc_live_oops_size->push(size);
2873 }
2874 }
2875
2876
2877 void PSParallelCompact::compaction_complete() {
2878 if (RecordMarkSweepCompaction) {
2879 GrowableArray<HeapWord*>* _tmp_live_oops = _cur_gc_live_oops;
2880 GrowableArray<HeapWord*>* _tmp_live_oops_moved_to = _cur_gc_live_oops_moved_to;
2881 GrowableArray<size_t> * _tmp_live_oops_size = _cur_gc_live_oops_size;
2882
2883 _cur_gc_live_oops = _last_gc_live_oops;
2884 _cur_gc_live_oops_moved_to = _last_gc_live_oops_moved_to;
2885 _cur_gc_live_oops_size = _last_gc_live_oops_size;
2886 _last_gc_live_oops = _tmp_live_oops;
2887 _last_gc_live_oops_moved_to = _tmp_live_oops_moved_to;
2888 _last_gc_live_oops_size = _tmp_live_oops_size;
2889 }
2890 }
2891
2892
2893 void PSParallelCompact::print_new_location_of_heap_address(HeapWord* q) {
2894 if (!RecordMarkSweepCompaction) {
2895 tty->print_cr("Requires RecordMarkSweepCompaction to be enabled");
2896 return;
2897 }
2898
2899 if (_last_gc_live_oops == NULL) {
2900 tty->print_cr("No compaction information gathered yet");
2901 return;
2902 }
2903
2904 for (int i = 0; i < _last_gc_live_oops->length(); i++) {
2905 HeapWord* old_oop = _last_gc_live_oops->at(i);
2906 size_t sz = _last_gc_live_oops_size->at(i);
2907 if (old_oop <= q && q < (old_oop + sz)) {
2908 HeapWord* new_oop = _last_gc_live_oops_moved_to->at(i);
2909 size_t offset = (q - old_oop);
2910 tty->print_cr("Address " PTR_FORMAT, q);
2911 tty->print_cr(" Was in oop " PTR_FORMAT ", size %d, at offset %d", old_oop, sz, offset);
2912 tty->print_cr(" Now in oop " PTR_FORMAT ", actual address " PTR_FORMAT, new_oop, new_oop + offset);
2913 return;
2914 }
2915 }
2916
2917 tty->print_cr("Address " PTR_FORMAT " not found in live oop information from last GC", q);
2918 }
2919 #endif //VALIDATE_MARK_SWEEP
2920
2921 // Update interior oops in the ranges of regions [beg_region, end_region).
2922 void
2923 PSParallelCompact::update_and_deadwood_in_dense_prefix(ParCompactionManager* cm,
2924 SpaceId space_id,
2925 size_t beg_region,
2926 size_t end_region) {
2927 ParallelCompactData& sd = summary_data();
2928 ParMarkBitMap* const mbm = mark_bitmap();
2929
2930 HeapWord* beg_addr = sd.region_to_addr(beg_region);
2931 HeapWord* const end_addr = sd.region_to_addr(end_region);
2932 assert(beg_region <= end_region, "bad region range");
2933 assert(end_addr <= dense_prefix(space_id), "not in the dense prefix");
2934
2935 #ifdef ASSERT
2936 // Claim the regions to avoid triggering an assert when they are marked as
2937 // filled.
2938 for (size_t claim_region = beg_region; claim_region < end_region; ++claim_region) {
2939 assert(sd.region(claim_region)->claim_unsafe(), "claim() failed");
2940 }
2941 #endif // #ifdef ASSERT
2942
2943 if (beg_addr != space(space_id)->bottom()) {
2944 // Find the first live object or block of dead space that *starts* in this
2945 // range of regions. If a partial object crosses onto the region, skip it;
2946 // it will be marked for 'deferred update' when the object head is
2947 // processed. If dead space crosses onto the region, it is also skipped; it
2948 // will be filled when the prior region is processed. If neither of those
2949 // apply, the first word in the region is the start of a live object or dead
2950 // space.
2951 assert(beg_addr > space(space_id)->bottom(), "sanity");
2952 const RegionData* const cp = sd.region(beg_region);
2953 if (cp->partial_obj_size() != 0) {
2954 beg_addr = sd.partial_obj_end(beg_region);
2955 } else if (dead_space_crosses_boundary(cp, mbm->addr_to_bit(beg_addr))) {
2956 beg_addr = mbm->find_obj_beg(beg_addr, end_addr);
2957 }
2958 }
2959
2960 if (beg_addr < end_addr) {
2961 // A live object or block of dead space starts in this range of Regions.
2962 HeapWord* const dense_prefix_end = dense_prefix(space_id);
2963
2964 // Create closures and iterate.
2965 UpdateOnlyClosure update_closure(mbm, cm, space_id);
2966 FillClosure fill_closure(cm, space_id);
2967 ParMarkBitMap::IterationStatus status;
2968 status = mbm->iterate(&update_closure, &fill_closure, beg_addr, end_addr,
2969 dense_prefix_end);
2970 if (status == ParMarkBitMap::incomplete) {
2971 update_closure.do_addr(update_closure.source());
2972 }
2973 }
2974
2975 // Mark the regions as filled.
2976 RegionData* const beg_cp = sd.region(beg_region);
2977 RegionData* const end_cp = sd.region(end_region);
2978 for (RegionData* cp = beg_cp; cp < end_cp; ++cp) {
2979 cp->set_completed();
2980 }
2981 }
2982
2983 // Return the SpaceId for the space containing addr. If addr is not in the
2984 // heap, last_space_id is returned. In debug mode it expects the address to be
2985 // in the heap and asserts such.
2986 PSParallelCompact::SpaceId PSParallelCompact::space_id(HeapWord* addr) {
2987 assert(Universe::heap()->is_in_reserved(addr), "addr not in the heap");
2988
2989 for (unsigned int id = perm_space_id; id < last_space_id; ++id) {
2990 if (_space_info[id].space()->contains(addr)) {
2991 return SpaceId(id);
2992 }
2993 }
2994
2995 assert(false, "no space contains the addr");
2996 return last_space_id;
2997 }
2998
2999 void PSParallelCompact::update_deferred_objects(ParCompactionManager* cm,
3000 SpaceId id) {
3001 assert(id < last_space_id, "bad space id");
3002
3003 ParallelCompactData& sd = summary_data();
3004 const SpaceInfo* const space_info = _space_info + id;
3005 ObjectStartArray* const start_array = space_info->start_array();
3006
3007 const MutableSpace* const space = space_info->space();
3008 assert(space_info->dense_prefix() >= space->bottom(), "dense_prefix not set");
3009 HeapWord* const beg_addr = space_info->dense_prefix();
3010 HeapWord* const end_addr = sd.region_align_up(space_info->new_top());
3011
3012 const RegionData* const beg_region = sd.addr_to_region_ptr(beg_addr);
3013 const RegionData* const end_region = sd.addr_to_region_ptr(end_addr);
3014 const RegionData* cur_region;
3015 for (cur_region = beg_region; cur_region < end_region; ++cur_region) {
3016 HeapWord* const addr = cur_region->deferred_obj_addr();
3017 if (addr != NULL) {
3018 if (start_array != NULL) {
3019 start_array->allocate_block(addr);
3020 }
3021 oop(addr)->update_contents(cm);
3022 assert(oop(addr)->is_oop_or_null(), "should be an oop now");
3023 }
3024 }
3025 }
3026
3027 // Skip over count live words starting from beg, and return the address of the
3028 // next live word. Unless marked, the word corresponding to beg is assumed to
3029 // be dead. Callers must either ensure beg does not correspond to the middle of
3030 // an object, or account for those live words in some other way. Callers must
3031 // also ensure that there are enough live words in the range [beg, end) to skip.
3032 HeapWord*
3033 PSParallelCompact::skip_live_words(HeapWord* beg, HeapWord* end, size_t count)
3034 {
3035 assert(count > 0, "sanity");
3036
3037 ParMarkBitMap* m = mark_bitmap();
3038 idx_t bits_to_skip = m->words_to_bits(count);
3039 idx_t cur_beg = m->addr_to_bit(beg);
3040 const idx_t search_end = BitMap::word_align_up(m->addr_to_bit(end));
3041
3042 do {
3043 cur_beg = m->find_obj_beg(cur_beg, search_end);
3044 idx_t cur_end = m->find_obj_end(cur_beg, search_end);
3045 const size_t obj_bits = cur_end - cur_beg + 1;
3046 if (obj_bits > bits_to_skip) {
3047 return m->bit_to_addr(cur_beg + bits_to_skip);
3048 }
3049 bits_to_skip -= obj_bits;
3050 cur_beg = cur_end + 1;
3051 } while (bits_to_skip > 0);
3052
3053 // Skipping the desired number of words landed just past the end of an object.
3054 // Find the start of the next object.
3055 cur_beg = m->find_obj_beg(cur_beg, search_end);
3056 assert(cur_beg < m->addr_to_bit(end), "not enough live words to skip");
3057 return m->bit_to_addr(cur_beg);
3058 }
3059
3060 HeapWord* PSParallelCompact::first_src_addr(HeapWord* const dest_addr,
3061 SpaceId src_space_id,
3062 size_t src_region_idx)
3063 {
3064 assert(summary_data().is_region_aligned(dest_addr), "not aligned");
3065
3066 const SplitInfo& split_info = _space_info[src_space_id].split_info();
3067 if (split_info.dest_region_addr() == dest_addr) {
3068 // The partial object ending at the split point contains the first word to
3069 // be copied to dest_addr.
3070 return split_info.first_src_addr();
3071 }
3072
3073 const ParallelCompactData& sd = summary_data();
3074 ParMarkBitMap* const bitmap = mark_bitmap();
3075 const size_t RegionSize = ParallelCompactData::RegionSize;
3076
3077 assert(sd.is_region_aligned(dest_addr), "not aligned");
3078 const RegionData* const src_region_ptr = sd.region(src_region_idx);
3079 const size_t partial_obj_size = src_region_ptr->partial_obj_size();
3080 HeapWord* const src_region_destination = src_region_ptr->destination();
3081
3082 assert(dest_addr >= src_region_destination, "wrong src region");
3083 assert(src_region_ptr->data_size() > 0, "src region cannot be empty");
3084
3085 HeapWord* const src_region_beg = sd.region_to_addr(src_region_idx);
3086 HeapWord* const src_region_end = src_region_beg + RegionSize;
3087
3088 HeapWord* addr = src_region_beg;
3089 if (dest_addr == src_region_destination) {
3090 // Return the first live word in the source region.
3091 if (partial_obj_size == 0) {
3092 addr = bitmap->find_obj_beg(addr, src_region_end);
3093 assert(addr < src_region_end, "no objects start in src region");
3094 }
3095 return addr;
3096 }
3097
3098 // Must skip some live data.
3099 size_t words_to_skip = dest_addr - src_region_destination;
3100 assert(src_region_ptr->data_size() > words_to_skip, "wrong src region");
3101
3102 if (partial_obj_size >= words_to_skip) {
3103 // All the live words to skip are part of the partial object.
3104 addr += words_to_skip;
3105 if (partial_obj_size == words_to_skip) {
3106 // Find the first live word past the partial object.
3107 addr = bitmap->find_obj_beg(addr, src_region_end);
3108 assert(addr < src_region_end, "wrong src region");
3109 }
3110 return addr;
3111 }
3112
3113 // Skip over the partial object (if any).
3114 if (partial_obj_size != 0) {
3115 words_to_skip -= partial_obj_size;
3116 addr += partial_obj_size;
3117 }
3118
3119 // Skip over live words due to objects that start in the region.
3120 addr = skip_live_words(addr, src_region_end, words_to_skip);
3121 assert(addr < src_region_end, "wrong src region");
3122 return addr;
3123 }
3124
3125 void PSParallelCompact::decrement_destination_counts(ParCompactionManager* cm,
3126 SpaceId src_space_id,
3127 size_t beg_region,
3128 HeapWord* end_addr)
3129 {
3130 ParallelCompactData& sd = summary_data();
3131
3132 #ifdef ASSERT
3133 MutableSpace* const src_space = _space_info[src_space_id].space();
3134 HeapWord* const beg_addr = sd.region_to_addr(beg_region);
3135 assert(src_space->contains(beg_addr) || beg_addr == src_space->end(),
3136 "src_space_id does not match beg_addr");
3137 assert(src_space->contains(end_addr) || end_addr == src_space->end(),
3138 "src_space_id does not match end_addr");
3139 #endif // #ifdef ASSERT
3140
3141 RegionData* const beg = sd.region(beg_region);
3142 RegionData* const end = sd.addr_to_region_ptr(sd.region_align_up(end_addr));
3143
3144 // Regions up to new_top() are enqueued if they become available.
3145 HeapWord* const new_top = _space_info[src_space_id].new_top();
3146 RegionData* const enqueue_end =
3147 sd.addr_to_region_ptr(sd.region_align_up(new_top));
3148
3149 for (RegionData* cur = beg; cur < end; ++cur) {
3150 assert(cur->data_size() > 0, "region must have live data");
3151 cur->decrement_destination_count();
3152 if (cur < enqueue_end && cur->available() && cur->claim()) {
3153 cm->push_region(sd.region(cur));
3154 }
3155 }
3156 }
3157
3158 size_t PSParallelCompact::next_src_region(MoveAndUpdateClosure& closure,
3159 SpaceId& src_space_id,
3160 HeapWord*& src_space_top,
3161 HeapWord* end_addr)
3162 {
3163 typedef ParallelCompactData::RegionData RegionData;
3164
3165 ParallelCompactData& sd = PSParallelCompact::summary_data();
3166 const size_t region_size = ParallelCompactData::RegionSize;
3167
3168 size_t src_region_idx = 0;
3169
3170 // Skip empty regions (if any) up to the top of the space.
3171 HeapWord* const src_aligned_up = sd.region_align_up(end_addr);
3172 RegionData* src_region_ptr = sd.addr_to_region_ptr(src_aligned_up);
3173 HeapWord* const top_aligned_up = sd.region_align_up(src_space_top);
3174 const RegionData* const top_region_ptr =
3175 sd.addr_to_region_ptr(top_aligned_up);
3176 while (src_region_ptr < top_region_ptr && src_region_ptr->data_size() == 0) {
3177 ++src_region_ptr;
3178 }
3179
3180 if (src_region_ptr < top_region_ptr) {
3181 // The next source region is in the current space. Update src_region_idx
3182 // and the source address to match src_region_ptr.
3183 src_region_idx = sd.region(src_region_ptr);
3184 HeapWord* const src_region_addr = sd.region_to_addr(src_region_idx);
3185 if (src_region_addr > closure.source()) {
3186 closure.set_source(src_region_addr);
3187 }
3188 return src_region_idx;
3189 }
3190
3191 // Switch to a new source space and find the first non-empty region.
3192 unsigned int space_id = src_space_id + 1;
3193 assert(space_id < last_space_id, "not enough spaces");
3194
3195 HeapWord* const destination = closure.destination();
3196
3197 do {
3198 MutableSpace* space = _space_info[space_id].space();
3199 HeapWord* const bottom = space->bottom();
3200 const RegionData* const bottom_cp = sd.addr_to_region_ptr(bottom);
3201
3202 // Iterate over the spaces that do not compact into themselves.
3203 if (bottom_cp->destination() != bottom) {
3204 HeapWord* const top_aligned_up = sd.region_align_up(space->top());
3205 const RegionData* const top_cp = sd.addr_to_region_ptr(top_aligned_up);
3206
3207 for (const RegionData* src_cp = bottom_cp; src_cp < top_cp; ++src_cp) {
3208 if (src_cp->live_obj_size() > 0) {
3209 // Found it.
3210 assert(src_cp->destination() == destination,
3211 "first live obj in the space must match the destination");
3212 assert(src_cp->partial_obj_size() == 0,
3213 "a space cannot begin with a partial obj");
3214
3215 src_space_id = SpaceId(space_id);
3216 src_space_top = space->top();
3217 const size_t src_region_idx = sd.region(src_cp);
3218 closure.set_source(sd.region_to_addr(src_region_idx));
3219 return src_region_idx;
3220 } else {
3221 assert(src_cp->data_size() == 0, "sanity");
3222 }
3223 }
3224 }
3225 } while (++space_id < last_space_id);
3226
3227 assert(false, "no source region was found");
3228 return 0;
3229 }
3230
3231 void PSParallelCompact::fill_region(ParCompactionManager* cm, size_t region_idx)
3232 {
3233 typedef ParMarkBitMap::IterationStatus IterationStatus;
3234 const size_t RegionSize = ParallelCompactData::RegionSize;
3235 ParMarkBitMap* const bitmap = mark_bitmap();
3236 ParallelCompactData& sd = summary_data();
3237 RegionData* const region_ptr = sd.region(region_idx);
3238
3239 // Get the items needed to construct the closure.
3240 HeapWord* dest_addr = sd.region_to_addr(region_idx);
3241 SpaceId dest_space_id = space_id(dest_addr);
3242 ObjectStartArray* start_array = _space_info[dest_space_id].start_array();
3243 HeapWord* new_top = _space_info[dest_space_id].new_top();
3244 assert(dest_addr < new_top, "sanity");
3245 const size_t words = MIN2(pointer_delta(new_top, dest_addr), RegionSize);
3246
3247 // Get the source region and related info.
3248 size_t src_region_idx = region_ptr->source_region();
3249 SpaceId src_space_id = space_id(sd.region_to_addr(src_region_idx));
3250 HeapWord* src_space_top = _space_info[src_space_id].space()->top();
3251
3252 MoveAndUpdateClosure closure(bitmap, cm, start_array, dest_addr, words);
3253 closure.set_source(first_src_addr(dest_addr, src_space_id, src_region_idx));
3254
3255 // Adjust src_region_idx to prepare for decrementing destination counts (the
3256 // destination count is not decremented when a region is copied to itself).
3257 if (src_region_idx == region_idx) {
3258 src_region_idx += 1;
3259 }
3260
3261 if (bitmap->is_unmarked(closure.source())) {
3262 // The first source word is in the middle of an object; copy the remainder
3263 // of the object or as much as will fit. The fact that pointer updates were
3264 // deferred will be noted when the object header is processed.
3265 HeapWord* const old_src_addr = closure.source();
3266 closure.copy_partial_obj();
3267 if (closure.is_full()) {
3268 decrement_destination_counts(cm, src_space_id, src_region_idx,
3269 closure.source());
3270 region_ptr->set_deferred_obj_addr(NULL);
3271 region_ptr->set_completed();
3272 return;
3273 }
3274
3275 HeapWord* const end_addr = sd.region_align_down(closure.source());
3276 if (sd.region_align_down(old_src_addr) != end_addr) {
3277 // The partial object was copied from more than one source region.
3278 decrement_destination_counts(cm, src_space_id, src_region_idx, end_addr);
3279
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 }
3285 }
3286
3287 do {
3288 HeapWord* const cur_addr = closure.source();
3289 HeapWord* const end_addr = MIN2(sd.region_align_up(cur_addr + 1),
3290 src_space_top);
3291 IterationStatus status = bitmap->iterate(&closure, cur_addr, end_addr);
3292
3293 if (status == ParMarkBitMap::incomplete) {
3294 // The last obj that starts in the source region does not end in the
3295 // region.
3296 assert(closure.source() < end_addr, "sanity");
3297 HeapWord* const obj_beg = closure.source();
3298 HeapWord* const range_end = MIN2(obj_beg + closure.words_remaining(),
3299 src_space_top);
3300 HeapWord* const obj_end = bitmap->find_obj_end(obj_beg, range_end);
3301 if (obj_end < range_end) {
3302 // The end was found; the entire object will fit.
3303 status = closure.do_addr(obj_beg, bitmap->obj_size(obj_beg, obj_end));
3304 assert(status != ParMarkBitMap::would_overflow, "sanity");
3305 } else {
3306 // The end was not found; the object will not fit.
3307 assert(range_end < src_space_top, "obj cannot cross space boundary");
3308 status = ParMarkBitMap::would_overflow;
3309 }
3310 }
3311
3312 if (status == ParMarkBitMap::would_overflow) {
3313 // The last object did not fit. Note that interior oop updates were
3314 // deferred, then copy enough of the object to fill the region.
3315 region_ptr->set_deferred_obj_addr(closure.destination());
3316 status = closure.copy_until_full(); // copies from closure.source()
3317
3318 decrement_destination_counts(cm, src_space_id, src_region_idx,
3319 closure.source());
3320 region_ptr->set_completed();
3321 return;
3322 }
3323
3324 if (status == ParMarkBitMap::full) {
3325 decrement_destination_counts(cm, src_space_id, src_region_idx,
3326 closure.source());
3327 region_ptr->set_deferred_obj_addr(NULL);
3328 region_ptr->set_completed();
3329 return;
3330 }
3331
3332 decrement_destination_counts(cm, src_space_id, src_region_idx, end_addr);
3333
3334 // Move to the next source region, possibly switching spaces as well. All
3335 // args except end_addr may be modified.
3336 src_region_idx = next_src_region(closure, src_space_id, src_space_top,
3337 end_addr);
3338 } while (true);
3339 }
3340
3341 void
3342 PSParallelCompact::move_and_update(ParCompactionManager* cm, SpaceId space_id) {
3343 const MutableSpace* sp = space(space_id);
3344 if (sp->is_empty()) {
3345 return;
3346 }
3347
3348 ParallelCompactData& sd = PSParallelCompact::summary_data();
3349 ParMarkBitMap* const bitmap = mark_bitmap();
3350 HeapWord* const dp_addr = dense_prefix(space_id);
3351 HeapWord* beg_addr = sp->bottom();
3352 HeapWord* end_addr = sp->top();
3353
3354 #ifdef ASSERT
3355 assert(beg_addr <= dp_addr && dp_addr <= end_addr, "bad dense prefix");
3356 if (cm->should_verify_only()) {
3357 VerifyUpdateClosure verify_update(cm, sp);
3358 bitmap->iterate(&verify_update, beg_addr, end_addr);
3359 return;
3360 }
3361
3362 if (cm->should_reset_only()) {
3363 ResetObjectsClosure reset_objects(cm);
3364 bitmap->iterate(&reset_objects, beg_addr, end_addr);
3365 return;
3366 }
3367 #endif
3368
3369 const size_t beg_region = sd.addr_to_region_idx(beg_addr);
3370 const size_t dp_region = sd.addr_to_region_idx(dp_addr);
3371 if (beg_region < dp_region) {
3372 update_and_deadwood_in_dense_prefix(cm, space_id, beg_region, dp_region);
3373 }
3374
3375 // The destination of the first live object that starts in the region is one
3376 // past the end of the partial object entering the region (if any).
3377 HeapWord* const dest_addr = sd.partial_obj_end(dp_region);
3378 HeapWord* const new_top = _space_info[space_id].new_top();
3379 assert(new_top >= dest_addr, "bad new_top value");
3380 const size_t words = pointer_delta(new_top, dest_addr);
3381
3382 if (words > 0) {
3383 ObjectStartArray* start_array = _space_info[space_id].start_array();
3384 MoveAndUpdateClosure closure(bitmap, cm, start_array, dest_addr, words);
3385
3386 ParMarkBitMap::IterationStatus status;
3387 status = bitmap->iterate(&closure, dest_addr, end_addr);
3388 assert(status == ParMarkBitMap::full, "iteration not complete");
3389 assert(bitmap->find_obj_beg(closure.source(), end_addr) == end_addr,
3390 "live objects skipped because closure is full");
3391 }
3392 }
3393
3394 jlong PSParallelCompact::millis_since_last_gc() {
3395 jlong ret_val = os::javaTimeMillis() - _time_of_last_gc;
3396 // XXX See note in genCollectedHeap::millis_since_last_gc().
3397 if (ret_val < 0) {
3398 NOT_PRODUCT(warning("time warp: %d", ret_val);)
3399 return 0;
3400 }
3401 return ret_val;
3402 }
3403
3404 void PSParallelCompact::reset_millis_since_last_gc() {
3405 _time_of_last_gc = os::javaTimeMillis();
3406 }
3407
3408 ParMarkBitMap::IterationStatus MoveAndUpdateClosure::copy_until_full()
3409 {
3410 if (source() != destination()) {
3411 DEBUG_ONLY(PSParallelCompact::check_new_location(source(), destination());)
3412 Copy::aligned_conjoint_words(source(), destination(), words_remaining());
3413 }
3414 update_state(words_remaining());
3415 assert(is_full(), "sanity");
3416 return ParMarkBitMap::full;
3417 }
3418
3419 void MoveAndUpdateClosure::copy_partial_obj()
3420 {
3421 size_t words = words_remaining();
3422
3423 HeapWord* const range_end = MIN2(source() + words, bitmap()->region_end());
3424 HeapWord* const end_addr = bitmap()->find_obj_end(source(), range_end);
3425 if (end_addr < range_end) {
3426 words = bitmap()->obj_size(source(), end_addr);
3427 }
3428
3429 // This test is necessary; if omitted, the pointer updates to a partial object
3430 // that crosses the dense prefix boundary could be overwritten.
3431 if (source() != destination()) {
3432 DEBUG_ONLY(PSParallelCompact::check_new_location(source(), destination());)
3433 Copy::aligned_conjoint_words(source(), destination(), words);
3434 }
3435 update_state(words);
3436 }
3437
3438 ParMarkBitMapClosure::IterationStatus
3439 MoveAndUpdateClosure::do_addr(HeapWord* addr, size_t words) {
3440 assert(destination() != NULL, "sanity");
3441 assert(bitmap()->obj_size(addr) == words, "bad size");
3442
3443 _source = addr;
3444 assert(PSParallelCompact::summary_data().calc_new_pointer(source()) ==
3445 destination(), "wrong destination");
3446
3447 if (words > words_remaining()) {
3448 return ParMarkBitMap::would_overflow;
3449 }
3450
3451 // The start_array must be updated even if the object is not moving.
3452 if (_start_array != NULL) {
3453 _start_array->allocate_block(destination());
3454 }
3455
3456 if (destination() != source()) {
3457 DEBUG_ONLY(PSParallelCompact::check_new_location(source(), destination());)
3458 Copy::aligned_conjoint_words(source(), destination(), words);
3459 }
3460
3461 oop moved_oop = (oop) destination();
3462 moved_oop->update_contents(compaction_manager());
3463 assert(moved_oop->is_oop_or_null(), "Object should be whole at this point");
3464
3465 update_state(words);
3466 assert(destination() == (HeapWord*)moved_oop + moved_oop->size(), "sanity");
3467 return is_full() ? ParMarkBitMap::full : ParMarkBitMap::incomplete;
3468 }
3469
3470 UpdateOnlyClosure::UpdateOnlyClosure(ParMarkBitMap* mbm,
3471 ParCompactionManager* cm,
3472 PSParallelCompact::SpaceId space_id) :
3473 ParMarkBitMapClosure(mbm, cm),
3474 _space_id(space_id),
3475 _start_array(PSParallelCompact::start_array(space_id))
3476 {
3477 }
3478
3479 // Updates the references in the object to their new values.
3480 ParMarkBitMapClosure::IterationStatus
3481 UpdateOnlyClosure::do_addr(HeapWord* addr, size_t words) {
3482 do_addr(addr);
3483 return ParMarkBitMap::incomplete;
3484 }
3485
3486 // Verify the new location using the forwarding pointer
3487 // from MarkSweep::mark_sweep_phase2(). Set the mark_word
3488 // to the initial value.
3489 ParMarkBitMapClosure::IterationStatus
3490 PSParallelCompact::VerifyUpdateClosure::do_addr(HeapWord* addr, size_t words) {
3491 // The second arg (words) is not used.
3492 oop obj = (oop) addr;
3493 HeapWord* forwarding_ptr = (HeapWord*) obj->mark()->decode_pointer();
3494 HeapWord* new_pointer = summary_data().calc_new_pointer(obj);
3495 if (forwarding_ptr == NULL) {
3496 // The object is dead or not moving.
3497 assert(bitmap()->is_unmarked(obj) || (new_pointer == (HeapWord*) obj),
3498 "Object liveness is wrong.");
3499 return ParMarkBitMap::incomplete;
3500 }
3501 assert(UseParallelOldGCDensePrefix ||
3502 (HeapMaximumCompactionInterval > 1) ||
3503 (MarkSweepAlwaysCompactCount > 1) ||
3504 (forwarding_ptr == new_pointer),
3505 "Calculation of new location is incorrect");
3506 return ParMarkBitMap::incomplete;
3507 }
3508
3509 // Reset objects modified for debug checking.
3510 ParMarkBitMapClosure::IterationStatus
3511 PSParallelCompact::ResetObjectsClosure::do_addr(HeapWord* addr, size_t words) {
3512 // The second arg (words) is not used.
3513 oop obj = (oop) addr;
3514 obj->init_mark();
3515 return ParMarkBitMap::incomplete;
3516 }
3517
3518 // Prepare for compaction. This method is executed once
3519 // (i.e., by a single thread) before compaction.
3520 // Save the updated location of the intArrayKlassObj for
3521 // filling holes in the dense prefix.
3522 void PSParallelCompact::compact_prologue() {
3523 _updated_int_array_klass_obj = (klassOop)
3524 summary_data().calc_new_pointer(Universe::intArrayKlassObj());
3525 }
3526