Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/g1/g1BlockOffsetTable.cpp @ 652:4aaa9f5e02a8
4766230: Hotspot vtable inconsistencies cause core dumps. 6579515. 6582242.
Reviewed-by: kamg, coleenp
author | acorn |
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date | Wed, 18 Mar 2009 17:20:57 -0400 |
parents | ad8c8ca4ab0f |
children | df6caf649ff7 |
rev | line source |
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342 | 1 /* |
470 | 2 * Copyright 2001-2008 Sun Microsystems, Inc. All Rights Reserved. |
342 | 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
21 * have any questions. | |
22 * | |
23 */ | |
24 | |
25 #include "incls/_precompiled.incl" | |
26 #include "incls/_g1BlockOffsetTable.cpp.incl" | |
27 | |
28 ////////////////////////////////////////////////////////////////////// | |
29 // G1BlockOffsetSharedArray | |
30 ////////////////////////////////////////////////////////////////////// | |
31 | |
32 G1BlockOffsetSharedArray::G1BlockOffsetSharedArray(MemRegion reserved, | |
33 size_t init_word_size) : | |
34 _reserved(reserved), _end(NULL) | |
35 { | |
36 size_t size = compute_size(reserved.word_size()); | |
37 ReservedSpace rs(ReservedSpace::allocation_align_size_up(size)); | |
38 if (!rs.is_reserved()) { | |
39 vm_exit_during_initialization("Could not reserve enough space for heap offset array"); | |
40 } | |
41 if (!_vs.initialize(rs, 0)) { | |
42 vm_exit_during_initialization("Could not reserve enough space for heap offset array"); | |
43 } | |
44 _offset_array = (u_char*)_vs.low_boundary(); | |
45 resize(init_word_size); | |
46 if (TraceBlockOffsetTable) { | |
47 gclog_or_tty->print_cr("G1BlockOffsetSharedArray::G1BlockOffsetSharedArray: "); | |
48 gclog_or_tty->print_cr(" " | |
49 " rs.base(): " INTPTR_FORMAT | |
50 " rs.size(): " INTPTR_FORMAT | |
51 " rs end(): " INTPTR_FORMAT, | |
52 rs.base(), rs.size(), rs.base() + rs.size()); | |
53 gclog_or_tty->print_cr(" " | |
54 " _vs.low_boundary(): " INTPTR_FORMAT | |
55 " _vs.high_boundary(): " INTPTR_FORMAT, | |
56 _vs.low_boundary(), | |
57 _vs.high_boundary()); | |
58 } | |
59 } | |
60 | |
61 void G1BlockOffsetSharedArray::resize(size_t new_word_size) { | |
62 assert(new_word_size <= _reserved.word_size(), "Resize larger than reserved"); | |
63 size_t new_size = compute_size(new_word_size); | |
64 size_t old_size = _vs.committed_size(); | |
65 size_t delta; | |
66 char* high = _vs.high(); | |
67 _end = _reserved.start() + new_word_size; | |
68 if (new_size > old_size) { | |
69 delta = ReservedSpace::page_align_size_up(new_size - old_size); | |
70 assert(delta > 0, "just checking"); | |
71 if (!_vs.expand_by(delta)) { | |
72 // Do better than this for Merlin | |
73 vm_exit_out_of_memory(delta, "offset table expansion"); | |
74 } | |
75 assert(_vs.high() == high + delta, "invalid expansion"); | |
76 // Initialization of the contents is left to the | |
77 // G1BlockOffsetArray that uses it. | |
78 } else { | |
79 delta = ReservedSpace::page_align_size_down(old_size - new_size); | |
80 if (delta == 0) return; | |
81 _vs.shrink_by(delta); | |
82 assert(_vs.high() == high - delta, "invalid expansion"); | |
83 } | |
84 } | |
85 | |
86 bool G1BlockOffsetSharedArray::is_card_boundary(HeapWord* p) const { | |
87 assert(p >= _reserved.start(), "just checking"); | |
88 size_t delta = pointer_delta(p, _reserved.start()); | |
89 return (delta & right_n_bits(LogN_words)) == (size_t)NoBits; | |
90 } | |
91 | |
92 | |
93 ////////////////////////////////////////////////////////////////////// | |
94 // G1BlockOffsetArray | |
95 ////////////////////////////////////////////////////////////////////// | |
96 | |
97 G1BlockOffsetArray::G1BlockOffsetArray(G1BlockOffsetSharedArray* array, | |
98 MemRegion mr, bool init_to_zero) : | |
99 G1BlockOffsetTable(mr.start(), mr.end()), | |
100 _unallocated_block(_bottom), | |
101 _array(array), _csp(NULL), | |
102 _init_to_zero(init_to_zero) { | |
103 assert(_bottom <= _end, "arguments out of order"); | |
104 if (!_init_to_zero) { | |
105 // initialize cards to point back to mr.start() | |
106 set_remainder_to_point_to_start(mr.start() + N_words, mr.end()); | |
107 _array->set_offset_array(0, 0); // set first card to 0 | |
108 } | |
109 } | |
110 | |
111 void G1BlockOffsetArray::set_space(Space* sp) { | |
112 _sp = sp; | |
113 _csp = sp->toContiguousSpace(); | |
114 } | |
115 | |
116 // The arguments follow the normal convention of denoting | |
117 // a right-open interval: [start, end) | |
118 void | |
119 G1BlockOffsetArray:: set_remainder_to_point_to_start(HeapWord* start, HeapWord* end) { | |
120 | |
121 if (start >= end) { | |
122 // The start address is equal to the end address (or to | |
123 // the right of the end address) so there are not cards | |
124 // that need to be updated.. | |
125 return; | |
126 } | |
127 | |
128 // Write the backskip value for each region. | |
129 // | |
130 // offset | |
131 // card 2nd 3rd | |
132 // | +- 1st | | | |
133 // v v v v | |
134 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+- | |
135 // |x|0|0|0|0|0|0|0|1|1|1|1|1|1| ... |1|1|1|1|2|2|2|2|2|2| ... | |
136 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+- | |
137 // 11 19 75 | |
138 // 12 | |
139 // | |
140 // offset card is the card that points to the start of an object | |
141 // x - offset value of offset card | |
142 // 1st - start of first logarithmic region | |
143 // 0 corresponds to logarithmic value N_words + 0 and 2**(3 * 0) = 1 | |
144 // 2nd - start of second logarithmic region | |
145 // 1 corresponds to logarithmic value N_words + 1 and 2**(3 * 1) = 8 | |
146 // 3rd - start of third logarithmic region | |
147 // 2 corresponds to logarithmic value N_words + 2 and 2**(3 * 2) = 64 | |
148 // | |
149 // integer below the block offset entry is an example of | |
150 // the index of the entry | |
151 // | |
152 // Given an address, | |
153 // Find the index for the address | |
154 // Find the block offset table entry | |
155 // Convert the entry to a back slide | |
156 // (e.g., with today's, offset = 0x81 => | |
157 // back slip = 2**(3*(0x81 - N_words)) = 2**3) = 8 | |
158 // Move back N (e.g., 8) entries and repeat with the | |
159 // value of the new entry | |
160 // | |
161 size_t start_card = _array->index_for(start); | |
162 size_t end_card = _array->index_for(end-1); | |
163 assert(start ==_array->address_for_index(start_card), "Precondition"); | |
164 assert(end ==_array->address_for_index(end_card)+N_words, "Precondition"); | |
165 set_remainder_to_point_to_start_incl(start_card, end_card); // closed interval | |
166 } | |
167 | |
168 // Unlike the normal convention in this code, the argument here denotes | |
169 // a closed, inclusive interval: [start_card, end_card], cf set_remainder_to_point_to_start() | |
170 // above. | |
171 void | |
172 G1BlockOffsetArray::set_remainder_to_point_to_start_incl(size_t start_card, size_t end_card) { | |
173 if (start_card > end_card) { | |
174 return; | |
175 } | |
176 assert(start_card > _array->index_for(_bottom), "Cannot be first card"); | |
177 assert(_array->offset_array(start_card-1) <= N_words, | |
178 "Offset card has an unexpected value"); | |
179 size_t start_card_for_region = start_card; | |
180 u_char offset = max_jubyte; | |
181 for (int i = 0; i < BlockOffsetArray::N_powers; i++) { | |
182 // -1 so that the the card with the actual offset is counted. Another -1 | |
183 // so that the reach ends in this region and not at the start | |
184 // of the next. | |
185 size_t reach = start_card - 1 + (BlockOffsetArray::power_to_cards_back(i+1) - 1); | |
186 offset = N_words + i; | |
187 if (reach >= end_card) { | |
188 _array->set_offset_array(start_card_for_region, end_card, offset); | |
189 start_card_for_region = reach + 1; | |
190 break; | |
191 } | |
192 _array->set_offset_array(start_card_for_region, reach, offset); | |
193 start_card_for_region = reach + 1; | |
194 } | |
195 assert(start_card_for_region > end_card, "Sanity check"); | |
196 DEBUG_ONLY(check_all_cards(start_card, end_card);) | |
197 } | |
198 | |
199 // The block [blk_start, blk_end) has been allocated; | |
200 // adjust the block offset table to represent this information; | |
201 // right-open interval: [blk_start, blk_end) | |
202 void | |
203 G1BlockOffsetArray::alloc_block(HeapWord* blk_start, HeapWord* blk_end) { | |
204 mark_block(blk_start, blk_end); | |
205 allocated(blk_start, blk_end); | |
206 } | |
207 | |
208 // Adjust BOT to show that a previously whole block has been split | |
209 // into two. | |
210 void G1BlockOffsetArray::split_block(HeapWord* blk, size_t blk_size, | |
211 size_t left_blk_size) { | |
212 // Verify that the BOT shows [blk, blk + blk_size) to be one block. | |
213 verify_single_block(blk, blk_size); | |
214 // Update the BOT to indicate that [blk + left_blk_size, blk + blk_size) | |
215 // is one single block. | |
216 mark_block(blk + left_blk_size, blk + blk_size); | |
217 } | |
218 | |
219 | |
220 // Action_mark - update the BOT for the block [blk_start, blk_end). | |
221 // Current typical use is for splitting a block. | |
222 // Action_single - udpate the BOT for an allocation. | |
223 // Action_verify - BOT verification. | |
224 void G1BlockOffsetArray::do_block_internal(HeapWord* blk_start, | |
225 HeapWord* blk_end, | |
226 Action action) { | |
227 assert(Universe::heap()->is_in_reserved(blk_start), | |
228 "reference must be into the heap"); | |
229 assert(Universe::heap()->is_in_reserved(blk_end-1), | |
230 "limit must be within the heap"); | |
231 // This is optimized to make the test fast, assuming we only rarely | |
232 // cross boundaries. | |
233 uintptr_t end_ui = (uintptr_t)(blk_end - 1); | |
234 uintptr_t start_ui = (uintptr_t)blk_start; | |
235 // Calculate the last card boundary preceding end of blk | |
236 intptr_t boundary_before_end = (intptr_t)end_ui; | |
237 clear_bits(boundary_before_end, right_n_bits(LogN)); | |
238 if (start_ui <= (uintptr_t)boundary_before_end) { | |
239 // blk starts at or crosses a boundary | |
240 // Calculate index of card on which blk begins | |
241 size_t start_index = _array->index_for(blk_start); | |
242 // Index of card on which blk ends | |
243 size_t end_index = _array->index_for(blk_end - 1); | |
244 // Start address of card on which blk begins | |
245 HeapWord* boundary = _array->address_for_index(start_index); | |
246 assert(boundary <= blk_start, "blk should start at or after boundary"); | |
247 if (blk_start != boundary) { | |
248 // blk starts strictly after boundary | |
249 // adjust card boundary and start_index forward to next card | |
250 boundary += N_words; | |
251 start_index++; | |
252 } | |
253 assert(start_index <= end_index, "monotonicity of index_for()"); | |
254 assert(boundary <= (HeapWord*)boundary_before_end, "tautology"); | |
255 switch (action) { | |
256 case Action_mark: { | |
257 if (init_to_zero()) { | |
258 _array->set_offset_array(start_index, boundary, blk_start); | |
259 break; | |
260 } // Else fall through to the next case | |
261 } | |
262 case Action_single: { | |
263 _array->set_offset_array(start_index, boundary, blk_start); | |
264 // We have finished marking the "offset card". We need to now | |
265 // mark the subsequent cards that this blk spans. | |
266 if (start_index < end_index) { | |
267 HeapWord* rem_st = _array->address_for_index(start_index) + N_words; | |
268 HeapWord* rem_end = _array->address_for_index(end_index) + N_words; | |
269 set_remainder_to_point_to_start(rem_st, rem_end); | |
270 } | |
271 break; | |
272 } | |
273 case Action_check: { | |
274 _array->check_offset_array(start_index, boundary, blk_start); | |
275 // We have finished checking the "offset card". We need to now | |
276 // check the subsequent cards that this blk spans. | |
277 check_all_cards(start_index + 1, end_index); | |
278 break; | |
279 } | |
280 default: | |
281 ShouldNotReachHere(); | |
282 } | |
283 } | |
284 } | |
285 | |
286 // The card-interval [start_card, end_card] is a closed interval; this | |
287 // is an expensive check -- use with care and only under protection of | |
288 // suitable flag. | |
289 void G1BlockOffsetArray::check_all_cards(size_t start_card, size_t end_card) const { | |
290 | |
291 if (end_card < start_card) { | |
292 return; | |
293 } | |
294 guarantee(_array->offset_array(start_card) == N_words, "Wrong value in second card"); | |
295 for (size_t c = start_card + 1; c <= end_card; c++ /* yeah! */) { | |
296 u_char entry = _array->offset_array(c); | |
297 if (c - start_card > BlockOffsetArray::power_to_cards_back(1)) { | |
298 guarantee(entry > N_words, "Should be in logarithmic region"); | |
299 } | |
300 size_t backskip = BlockOffsetArray::entry_to_cards_back(entry); | |
301 size_t landing_card = c - backskip; | |
302 guarantee(landing_card >= (start_card - 1), "Inv"); | |
303 if (landing_card >= start_card) { | |
304 guarantee(_array->offset_array(landing_card) <= entry, "monotonicity"); | |
305 } else { | |
306 guarantee(landing_card == start_card - 1, "Tautology"); | |
307 guarantee(_array->offset_array(landing_card) <= N_words, "Offset value"); | |
308 } | |
309 } | |
310 } | |
311 | |
312 // The range [blk_start, blk_end) represents a single contiguous block | |
313 // of storage; modify the block offset table to represent this | |
314 // information; Right-open interval: [blk_start, blk_end) | |
315 // NOTE: this method does _not_ adjust _unallocated_block. | |
316 void | |
317 G1BlockOffsetArray::single_block(HeapWord* blk_start, HeapWord* blk_end) { | |
318 do_block_internal(blk_start, blk_end, Action_single); | |
319 } | |
320 | |
321 // Mark the BOT such that if [blk_start, blk_end) straddles a card | |
322 // boundary, the card following the first such boundary is marked | |
323 // with the appropriate offset. | |
324 // NOTE: this method does _not_ adjust _unallocated_block or | |
325 // any cards subsequent to the first one. | |
326 void | |
327 G1BlockOffsetArray::mark_block(HeapWord* blk_start, HeapWord* blk_end) { | |
328 do_block_internal(blk_start, blk_end, Action_mark); | |
329 } | |
330 | |
331 void G1BlockOffsetArray::join_blocks(HeapWord* blk1, HeapWord* blk2) { | |
332 HeapWord* blk1_start = Universe::heap()->block_start(blk1); | |
333 HeapWord* blk2_start = Universe::heap()->block_start(blk2); | |
334 assert(blk1 == blk1_start && blk2 == blk2_start, | |
335 "Must be block starts."); | |
336 assert(blk1 + _sp->block_size(blk1) == blk2, "Must be contiguous."); | |
337 size_t blk1_start_index = _array->index_for(blk1); | |
338 size_t blk2_start_index = _array->index_for(blk2); | |
339 assert(blk1_start_index <= blk2_start_index, "sanity"); | |
340 HeapWord* blk2_card_start = _array->address_for_index(blk2_start_index); | |
341 if (blk2 == blk2_card_start) { | |
342 // blk2 starts a card. Does blk1 start on the prevous card, or futher | |
343 // back? | |
344 assert(blk1_start_index < blk2_start_index, "must be lower card."); | |
345 if (blk1_start_index + 1 == blk2_start_index) { | |
346 // previous card; new value for blk2 card is size of blk1. | |
347 _array->set_offset_array(blk2_start_index, (u_char) _sp->block_size(blk1)); | |
348 } else { | |
349 // Earlier card; go back a card. | |
350 _array->set_offset_array(blk2_start_index, N_words); | |
351 } | |
352 } else { | |
353 // blk2 does not start a card. Does it cross a card? If not, nothing | |
354 // to do. | |
355 size_t blk2_end_index = | |
356 _array->index_for(blk2 + _sp->block_size(blk2) - 1); | |
357 assert(blk2_end_index >= blk2_start_index, "sanity"); | |
358 if (blk2_end_index > blk2_start_index) { | |
359 // Yes, it crosses a card. The value for the next card must change. | |
360 if (blk1_start_index + 1 == blk2_start_index) { | |
361 // previous card; new value for second blk2 card is size of blk1. | |
362 _array->set_offset_array(blk2_start_index + 1, | |
363 (u_char) _sp->block_size(blk1)); | |
364 } else { | |
365 // Earlier card; go back a card. | |
366 _array->set_offset_array(blk2_start_index + 1, N_words); | |
367 } | |
368 } | |
369 } | |
370 } | |
371 | |
372 HeapWord* G1BlockOffsetArray::block_start_unsafe(const void* addr) { | |
373 assert(_bottom <= addr && addr < _end, | |
374 "addr must be covered by this Array"); | |
375 // Must read this exactly once because it can be modified by parallel | |
376 // allocation. | |
377 HeapWord* ub = _unallocated_block; | |
378 if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) { | |
379 assert(ub < _end, "tautology (see above)"); | |
380 return ub; | |
381 } | |
382 // Otherwise, find the block start using the table. | |
383 HeapWord* q = block_at_or_preceding(addr, false, 0); | |
384 return forward_to_block_containing_addr(q, addr); | |
385 } | |
386 | |
387 // This duplicates a little code from the above: unavoidable. | |
388 HeapWord* | |
389 G1BlockOffsetArray::block_start_unsafe_const(const void* addr) const { | |
390 assert(_bottom <= addr && addr < _end, | |
391 "addr must be covered by this Array"); | |
392 // Must read this exactly once because it can be modified by parallel | |
393 // allocation. | |
394 HeapWord* ub = _unallocated_block; | |
395 if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) { | |
396 assert(ub < _end, "tautology (see above)"); | |
397 return ub; | |
398 } | |
399 // Otherwise, find the block start using the table. | |
400 HeapWord* q = block_at_or_preceding(addr, false, 0); | |
401 HeapWord* n = q + _sp->block_size(q); | |
402 return forward_to_block_containing_addr_const(q, n, addr); | |
403 } | |
404 | |
405 | |
406 HeapWord* | |
407 G1BlockOffsetArray::forward_to_block_containing_addr_slow(HeapWord* q, | |
408 HeapWord* n, | |
409 const void* addr) { | |
410 // We're not in the normal case. We need to handle an important subcase | |
411 // here: LAB allocation. An allocation previously recorded in the | |
412 // offset table was actually a lab allocation, and was divided into | |
413 // several objects subsequently. Fix this situation as we answer the | |
414 // query, by updating entries as we cross them. | |
352
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415 |
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416 // If the fist object's end q is at the card boundary. Start refining |
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417 // with the corresponding card (the value of the entry will be basically |
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418 // set to 0). If the object crosses the boundary -- start from the next card. |
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419 size_t next_index = _array->index_for(n) + !_array->is_card_boundary(n); |
342 | 420 HeapWord* next_boundary = _array->address_for_index(next_index); |
421 if (csp() != NULL) { | |
422 if (addr >= csp()->top()) return csp()->top(); | |
423 while (next_boundary < addr) { | |
424 while (n <= next_boundary) { | |
425 q = n; | |
426 oop obj = oop(q); | |
427 if (obj->klass() == NULL) return q; | |
428 n += obj->size(); | |
429 } | |
430 assert(q <= next_boundary && n > next_boundary, "Consequence of loop"); | |
431 // [q, n) is the block that crosses the boundary. | |
432 alloc_block_work2(&next_boundary, &next_index, q, n); | |
433 } | |
434 } else { | |
435 while (next_boundary < addr) { | |
436 while (n <= next_boundary) { | |
437 q = n; | |
438 oop obj = oop(q); | |
439 if (obj->klass() == NULL) return q; | |
440 n += _sp->block_size(q); | |
441 } | |
442 assert(q <= next_boundary && n > next_boundary, "Consequence of loop"); | |
443 // [q, n) is the block that crosses the boundary. | |
444 alloc_block_work2(&next_boundary, &next_index, q, n); | |
445 } | |
446 } | |
447 return forward_to_block_containing_addr_const(q, n, addr); | |
448 } | |
449 | |
450 HeapWord* G1BlockOffsetArray::block_start_careful(const void* addr) const { | |
451 assert(_array->offset_array(0) == 0, "objects can't cross covered areas"); | |
452 | |
453 assert(_bottom <= addr && addr < _end, | |
454 "addr must be covered by this Array"); | |
455 // Must read this exactly once because it can be modified by parallel | |
456 // allocation. | |
457 HeapWord* ub = _unallocated_block; | |
458 if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) { | |
459 assert(ub < _end, "tautology (see above)"); | |
460 return ub; | |
461 } | |
462 | |
463 // Otherwise, find the block start using the table, but taking | |
464 // care (cf block_start_unsafe() above) not to parse any objects/blocks | |
465 // on the cards themsleves. | |
466 size_t index = _array->index_for(addr); | |
467 assert(_array->address_for_index(index) == addr, | |
468 "arg should be start of card"); | |
469 | |
470 HeapWord* q = (HeapWord*)addr; | |
471 uint offset; | |
472 do { | |
473 offset = _array->offset_array(index--); | |
474 q -= offset; | |
475 } while (offset == N_words); | |
476 assert(q <= addr, "block start should be to left of arg"); | |
477 return q; | |
478 } | |
479 | |
480 // Note that the committed size of the covered space may have changed, | |
481 // so the table size might also wish to change. | |
482 void G1BlockOffsetArray::resize(size_t new_word_size) { | |
483 HeapWord* new_end = _bottom + new_word_size; | |
484 if (_end < new_end && !init_to_zero()) { | |
485 // verify that the old and new boundaries are also card boundaries | |
486 assert(_array->is_card_boundary(_end), | |
487 "_end not a card boundary"); | |
488 assert(_array->is_card_boundary(new_end), | |
489 "new _end would not be a card boundary"); | |
490 // set all the newly added cards | |
491 _array->set_offset_array(_end, new_end, N_words); | |
492 } | |
493 _end = new_end; // update _end | |
494 } | |
495 | |
496 void G1BlockOffsetArray::set_region(MemRegion mr) { | |
497 _bottom = mr.start(); | |
498 _end = mr.end(); | |
499 } | |
500 | |
501 // | |
502 // threshold_ | |
503 // | _index_ | |
504 // v v | |
505 // +-------+-------+-------+-------+-------+ | |
506 // | i-1 | i | i+1 | i+2 | i+3 | | |
507 // +-------+-------+-------+-------+-------+ | |
508 // ( ^ ] | |
509 // block-start | |
510 // | |
511 void G1BlockOffsetArray::alloc_block_work2(HeapWord** threshold_, size_t* index_, | |
512 HeapWord* blk_start, HeapWord* blk_end) { | |
513 // For efficiency, do copy-in/copy-out. | |
514 HeapWord* threshold = *threshold_; | |
515 size_t index = *index_; | |
516 | |
517 assert(blk_start != NULL && blk_end > blk_start, | |
518 "phantom block"); | |
519 assert(blk_end > threshold, "should be past threshold"); | |
520 assert(blk_start <= threshold, "blk_start should be at or before threshold") | |
521 assert(pointer_delta(threshold, blk_start) <= N_words, | |
522 "offset should be <= BlockOffsetSharedArray::N"); | |
523 assert(Universe::heap()->is_in_reserved(blk_start), | |
524 "reference must be into the heap"); | |
525 assert(Universe::heap()->is_in_reserved(blk_end-1), | |
526 "limit must be within the heap"); | |
527 assert(threshold == _array->_reserved.start() + index*N_words, | |
528 "index must agree with threshold"); | |
529 | |
530 DEBUG_ONLY(size_t orig_index = index;) | |
531 | |
532 // Mark the card that holds the offset into the block. Note | |
533 // that _next_offset_index and _next_offset_threshold are not | |
534 // updated until the end of this method. | |
535 _array->set_offset_array(index, threshold, blk_start); | |
536 | |
537 // We need to now mark the subsequent cards that this blk spans. | |
538 | |
539 // Index of card on which blk ends. | |
540 size_t end_index = _array->index_for(blk_end - 1); | |
541 | |
542 // Are there more cards left to be updated? | |
543 if (index + 1 <= end_index) { | |
544 HeapWord* rem_st = _array->address_for_index(index + 1); | |
545 // Calculate rem_end this way because end_index | |
546 // may be the last valid index in the covered region. | |
547 HeapWord* rem_end = _array->address_for_index(end_index) + N_words; | |
548 set_remainder_to_point_to_start(rem_st, rem_end); | |
549 } | |
550 | |
551 index = end_index + 1; | |
552 // Calculate threshold_ this way because end_index | |
553 // may be the last valid index in the covered region. | |
554 threshold = _array->address_for_index(end_index) + N_words; | |
555 assert(threshold >= blk_end, "Incorrect offset threshold"); | |
556 | |
557 // index_ and threshold_ updated here. | |
558 *threshold_ = threshold; | |
559 *index_ = index; | |
560 | |
561 #ifdef ASSERT | |
562 // The offset can be 0 if the block starts on a boundary. That | |
563 // is checked by an assertion above. | |
564 size_t start_index = _array->index_for(blk_start); | |
565 HeapWord* boundary = _array->address_for_index(start_index); | |
566 assert((_array->offset_array(orig_index) == 0 && | |
567 blk_start == boundary) || | |
568 (_array->offset_array(orig_index) > 0 && | |
569 _array->offset_array(orig_index) <= N_words), | |
570 "offset array should have been set"); | |
571 for (size_t j = orig_index + 1; j <= end_index; j++) { | |
572 assert(_array->offset_array(j) > 0 && | |
573 _array->offset_array(j) <= | |
574 (u_char) (N_words+BlockOffsetArray::N_powers-1), | |
575 "offset array should have been set"); | |
576 } | |
577 #endif | |
578 } | |
579 | |
580 ////////////////////////////////////////////////////////////////////// | |
581 // G1BlockOffsetArrayContigSpace | |
582 ////////////////////////////////////////////////////////////////////// | |
583 | |
584 HeapWord* | |
585 G1BlockOffsetArrayContigSpace::block_start_unsafe(const void* addr) { | |
586 assert(_bottom <= addr && addr < _end, | |
587 "addr must be covered by this Array"); | |
588 HeapWord* q = block_at_or_preceding(addr, true, _next_offset_index-1); | |
589 return forward_to_block_containing_addr(q, addr); | |
590 } | |
591 | |
592 HeapWord* | |
593 G1BlockOffsetArrayContigSpace:: | |
594 block_start_unsafe_const(const void* addr) const { | |
595 assert(_bottom <= addr && addr < _end, | |
596 "addr must be covered by this Array"); | |
597 HeapWord* q = block_at_or_preceding(addr, true, _next_offset_index-1); | |
598 HeapWord* n = q + _sp->block_size(q); | |
599 return forward_to_block_containing_addr_const(q, n, addr); | |
600 } | |
601 | |
602 G1BlockOffsetArrayContigSpace:: | |
603 G1BlockOffsetArrayContigSpace(G1BlockOffsetSharedArray* array, | |
604 MemRegion mr) : | |
605 G1BlockOffsetArray(array, mr, true) | |
606 { | |
607 _next_offset_threshold = NULL; | |
608 _next_offset_index = 0; | |
609 } | |
610 | |
611 HeapWord* G1BlockOffsetArrayContigSpace::initialize_threshold() { | |
612 assert(!Universe::heap()->is_in_reserved(_array->_offset_array), | |
613 "just checking"); | |
614 _next_offset_index = _array->index_for(_bottom); | |
615 _next_offset_index++; | |
616 _next_offset_threshold = | |
617 _array->address_for_index(_next_offset_index); | |
618 return _next_offset_threshold; | |
619 } | |
620 | |
621 void G1BlockOffsetArrayContigSpace::zero_bottom_entry() { | |
622 assert(!Universe::heap()->is_in_reserved(_array->_offset_array), | |
623 "just checking"); | |
624 size_t bottom_index = _array->index_for(_bottom); | |
625 assert(_array->address_for_index(bottom_index) == _bottom, | |
626 "Precondition of call"); | |
627 _array->set_offset_array(bottom_index, 0); | |
628 } |