Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/g1/g1BlockOffsetTable.cpp @ 2132:4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
Summary: The recorded _sweep_limit may not necessarily remain a block boundary as the old generation expands during a concurrent cycle. Terminal actions inside the sweep closure need to be aware of this as they cross over the limit.
Reviewed-by: johnc, minqi
author | ysr |
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date | Thu, 06 Jan 2011 23:50:02 -0800 |
parents | f95d63e2154a |
children | 2250ee17e258 |
rev | line source |
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342 | 1 /* |
1972 | 2 * Copyright (c) 2001, 2010, Oracle and/or its affiliates. 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 * | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
342 | 22 * |
23 */ | |
24 | |
1972 | 25 #include "precompiled.hpp" |
26 #include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp" | |
27 #include "memory/space.hpp" | |
28 #include "oops/oop.inline.hpp" | |
29 #include "runtime/java.hpp" | |
342 | 30 |
31 ////////////////////////////////////////////////////////////////////// | |
32 // G1BlockOffsetSharedArray | |
33 ////////////////////////////////////////////////////////////////////// | |
34 | |
35 G1BlockOffsetSharedArray::G1BlockOffsetSharedArray(MemRegion reserved, | |
36 size_t init_word_size) : | |
37 _reserved(reserved), _end(NULL) | |
38 { | |
39 size_t size = compute_size(reserved.word_size()); | |
40 ReservedSpace rs(ReservedSpace::allocation_align_size_up(size)); | |
41 if (!rs.is_reserved()) { | |
42 vm_exit_during_initialization("Could not reserve enough space for heap offset array"); | |
43 } | |
44 if (!_vs.initialize(rs, 0)) { | |
45 vm_exit_during_initialization("Could not reserve enough space for heap offset array"); | |
46 } | |
47 _offset_array = (u_char*)_vs.low_boundary(); | |
48 resize(init_word_size); | |
49 if (TraceBlockOffsetTable) { | |
50 gclog_or_tty->print_cr("G1BlockOffsetSharedArray::G1BlockOffsetSharedArray: "); | |
51 gclog_or_tty->print_cr(" " | |
52 " rs.base(): " INTPTR_FORMAT | |
53 " rs.size(): " INTPTR_FORMAT | |
54 " rs end(): " INTPTR_FORMAT, | |
55 rs.base(), rs.size(), rs.base() + rs.size()); | |
56 gclog_or_tty->print_cr(" " | |
57 " _vs.low_boundary(): " INTPTR_FORMAT | |
58 " _vs.high_boundary(): " INTPTR_FORMAT, | |
59 _vs.low_boundary(), | |
60 _vs.high_boundary()); | |
61 } | |
62 } | |
63 | |
64 void G1BlockOffsetSharedArray::resize(size_t new_word_size) { | |
65 assert(new_word_size <= _reserved.word_size(), "Resize larger than reserved"); | |
66 size_t new_size = compute_size(new_word_size); | |
67 size_t old_size = _vs.committed_size(); | |
68 size_t delta; | |
69 char* high = _vs.high(); | |
70 _end = _reserved.start() + new_word_size; | |
71 if (new_size > old_size) { | |
72 delta = ReservedSpace::page_align_size_up(new_size - old_size); | |
73 assert(delta > 0, "just checking"); | |
74 if (!_vs.expand_by(delta)) { | |
75 // Do better than this for Merlin | |
76 vm_exit_out_of_memory(delta, "offset table expansion"); | |
77 } | |
78 assert(_vs.high() == high + delta, "invalid expansion"); | |
79 // Initialization of the contents is left to the | |
80 // G1BlockOffsetArray that uses it. | |
81 } else { | |
82 delta = ReservedSpace::page_align_size_down(old_size - new_size); | |
83 if (delta == 0) return; | |
84 _vs.shrink_by(delta); | |
85 assert(_vs.high() == high - delta, "invalid expansion"); | |
86 } | |
87 } | |
88 | |
89 bool G1BlockOffsetSharedArray::is_card_boundary(HeapWord* p) const { | |
90 assert(p >= _reserved.start(), "just checking"); | |
91 size_t delta = pointer_delta(p, _reserved.start()); | |
92 return (delta & right_n_bits(LogN_words)) == (size_t)NoBits; | |
93 } | |
94 | |
95 | |
96 ////////////////////////////////////////////////////////////////////// | |
97 // G1BlockOffsetArray | |
98 ////////////////////////////////////////////////////////////////////// | |
99 | |
100 G1BlockOffsetArray::G1BlockOffsetArray(G1BlockOffsetSharedArray* array, | |
101 MemRegion mr, bool init_to_zero) : | |
102 G1BlockOffsetTable(mr.start(), mr.end()), | |
103 _unallocated_block(_bottom), | |
104 _array(array), _csp(NULL), | |
105 _init_to_zero(init_to_zero) { | |
106 assert(_bottom <= _end, "arguments out of order"); | |
107 if (!_init_to_zero) { | |
108 // initialize cards to point back to mr.start() | |
109 set_remainder_to_point_to_start(mr.start() + N_words, mr.end()); | |
110 _array->set_offset_array(0, 0); // set first card to 0 | |
111 } | |
112 } | |
113 | |
114 void G1BlockOffsetArray::set_space(Space* sp) { | |
115 _sp = sp; | |
116 _csp = sp->toContiguousSpace(); | |
117 } | |
118 | |
119 // The arguments follow the normal convention of denoting | |
120 // a right-open interval: [start, end) | |
121 void | |
122 G1BlockOffsetArray:: set_remainder_to_point_to_start(HeapWord* start, HeapWord* end) { | |
123 | |
124 if (start >= end) { | |
125 // The start address is equal to the end address (or to | |
126 // the right of the end address) so there are not cards | |
127 // that need to be updated.. | |
128 return; | |
129 } | |
130 | |
131 // Write the backskip value for each region. | |
132 // | |
133 // offset | |
134 // card 2nd 3rd | |
135 // | +- 1st | | | |
136 // v v v v | |
137 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+- | |
138 // |x|0|0|0|0|0|0|0|1|1|1|1|1|1| ... |1|1|1|1|2|2|2|2|2|2| ... | |
139 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+- | |
140 // 11 19 75 | |
141 // 12 | |
142 // | |
143 // offset card is the card that points to the start of an object | |
144 // x - offset value of offset card | |
145 // 1st - start of first logarithmic region | |
146 // 0 corresponds to logarithmic value N_words + 0 and 2**(3 * 0) = 1 | |
147 // 2nd - start of second logarithmic region | |
148 // 1 corresponds to logarithmic value N_words + 1 and 2**(3 * 1) = 8 | |
149 // 3rd - start of third logarithmic region | |
150 // 2 corresponds to logarithmic value N_words + 2 and 2**(3 * 2) = 64 | |
151 // | |
152 // integer below the block offset entry is an example of | |
153 // the index of the entry | |
154 // | |
155 // Given an address, | |
156 // Find the index for the address | |
157 // Find the block offset table entry | |
158 // Convert the entry to a back slide | |
159 // (e.g., with today's, offset = 0x81 => | |
160 // back slip = 2**(3*(0x81 - N_words)) = 2**3) = 8 | |
161 // Move back N (e.g., 8) entries and repeat with the | |
162 // value of the new entry | |
163 // | |
164 size_t start_card = _array->index_for(start); | |
165 size_t end_card = _array->index_for(end-1); | |
166 assert(start ==_array->address_for_index(start_card), "Precondition"); | |
167 assert(end ==_array->address_for_index(end_card)+N_words, "Precondition"); | |
168 set_remainder_to_point_to_start_incl(start_card, end_card); // closed interval | |
169 } | |
170 | |
171 // Unlike the normal convention in this code, the argument here denotes | |
172 // a closed, inclusive interval: [start_card, end_card], cf set_remainder_to_point_to_start() | |
173 // above. | |
174 void | |
175 G1BlockOffsetArray::set_remainder_to_point_to_start_incl(size_t start_card, size_t end_card) { | |
176 if (start_card > end_card) { | |
177 return; | |
178 } | |
179 assert(start_card > _array->index_for(_bottom), "Cannot be first card"); | |
180 assert(_array->offset_array(start_card-1) <= N_words, | |
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181 "Offset card has an unexpected value"); |
342 | 182 size_t start_card_for_region = start_card; |
183 u_char offset = max_jubyte; | |
184 for (int i = 0; i < BlockOffsetArray::N_powers; i++) { | |
185 // -1 so that the the card with the actual offset is counted. Another -1 | |
186 // so that the reach ends in this region and not at the start | |
187 // of the next. | |
188 size_t reach = start_card - 1 + (BlockOffsetArray::power_to_cards_back(i+1) - 1); | |
189 offset = N_words + i; | |
190 if (reach >= end_card) { | |
191 _array->set_offset_array(start_card_for_region, end_card, offset); | |
192 start_card_for_region = reach + 1; | |
193 break; | |
194 } | |
195 _array->set_offset_array(start_card_for_region, reach, offset); | |
196 start_card_for_region = reach + 1; | |
197 } | |
198 assert(start_card_for_region > end_card, "Sanity check"); | |
199 DEBUG_ONLY(check_all_cards(start_card, end_card);) | |
200 } | |
201 | |
202 // The block [blk_start, blk_end) has been allocated; | |
203 // adjust the block offset table to represent this information; | |
204 // right-open interval: [blk_start, blk_end) | |
205 void | |
206 G1BlockOffsetArray::alloc_block(HeapWord* blk_start, HeapWord* blk_end) { | |
207 mark_block(blk_start, blk_end); | |
208 allocated(blk_start, blk_end); | |
209 } | |
210 | |
211 // Adjust BOT to show that a previously whole block has been split | |
212 // into two. | |
213 void G1BlockOffsetArray::split_block(HeapWord* blk, size_t blk_size, | |
214 size_t left_blk_size) { | |
215 // Verify that the BOT shows [blk, blk + blk_size) to be one block. | |
216 verify_single_block(blk, blk_size); | |
217 // Update the BOT to indicate that [blk + left_blk_size, blk + blk_size) | |
218 // is one single block. | |
219 mark_block(blk + left_blk_size, blk + blk_size); | |
220 } | |
221 | |
222 | |
223 // Action_mark - update the BOT for the block [blk_start, blk_end). | |
224 // Current typical use is for splitting a block. | |
225 // Action_single - udpate the BOT for an allocation. | |
226 // Action_verify - BOT verification. | |
227 void G1BlockOffsetArray::do_block_internal(HeapWord* blk_start, | |
228 HeapWord* blk_end, | |
229 Action action) { | |
230 assert(Universe::heap()->is_in_reserved(blk_start), | |
231 "reference must be into the heap"); | |
232 assert(Universe::heap()->is_in_reserved(blk_end-1), | |
233 "limit must be within the heap"); | |
234 // This is optimized to make the test fast, assuming we only rarely | |
235 // cross boundaries. | |
236 uintptr_t end_ui = (uintptr_t)(blk_end - 1); | |
237 uintptr_t start_ui = (uintptr_t)blk_start; | |
238 // Calculate the last card boundary preceding end of blk | |
239 intptr_t boundary_before_end = (intptr_t)end_ui; | |
240 clear_bits(boundary_before_end, right_n_bits(LogN)); | |
241 if (start_ui <= (uintptr_t)boundary_before_end) { | |
242 // blk starts at or crosses a boundary | |
243 // Calculate index of card on which blk begins | |
244 size_t start_index = _array->index_for(blk_start); | |
245 // Index of card on which blk ends | |
246 size_t end_index = _array->index_for(blk_end - 1); | |
247 // Start address of card on which blk begins | |
248 HeapWord* boundary = _array->address_for_index(start_index); | |
249 assert(boundary <= blk_start, "blk should start at or after boundary"); | |
250 if (blk_start != boundary) { | |
251 // blk starts strictly after boundary | |
252 // adjust card boundary and start_index forward to next card | |
253 boundary += N_words; | |
254 start_index++; | |
255 } | |
256 assert(start_index <= end_index, "monotonicity of index_for()"); | |
257 assert(boundary <= (HeapWord*)boundary_before_end, "tautology"); | |
258 switch (action) { | |
259 case Action_mark: { | |
260 if (init_to_zero()) { | |
261 _array->set_offset_array(start_index, boundary, blk_start); | |
262 break; | |
263 } // Else fall through to the next case | |
264 } | |
265 case Action_single: { | |
266 _array->set_offset_array(start_index, boundary, blk_start); | |
267 // We have finished marking the "offset card". We need to now | |
268 // mark the subsequent cards that this blk spans. | |
269 if (start_index < end_index) { | |
270 HeapWord* rem_st = _array->address_for_index(start_index) + N_words; | |
271 HeapWord* rem_end = _array->address_for_index(end_index) + N_words; | |
272 set_remainder_to_point_to_start(rem_st, rem_end); | |
273 } | |
274 break; | |
275 } | |
276 case Action_check: { | |
277 _array->check_offset_array(start_index, boundary, blk_start); | |
278 // We have finished checking the "offset card". We need to now | |
279 // check the subsequent cards that this blk spans. | |
280 check_all_cards(start_index + 1, end_index); | |
281 break; | |
282 } | |
283 default: | |
284 ShouldNotReachHere(); | |
285 } | |
286 } | |
287 } | |
288 | |
289 // The card-interval [start_card, end_card] is a closed interval; this | |
290 // is an expensive check -- use with care and only under protection of | |
291 // suitable flag. | |
292 void G1BlockOffsetArray::check_all_cards(size_t start_card, size_t end_card) const { | |
293 | |
294 if (end_card < start_card) { | |
295 return; | |
296 } | |
297 guarantee(_array->offset_array(start_card) == N_words, "Wrong value in second card"); | |
298 for (size_t c = start_card + 1; c <= end_card; c++ /* yeah! */) { | |
299 u_char entry = _array->offset_array(c); | |
300 if (c - start_card > BlockOffsetArray::power_to_cards_back(1)) { | |
301 guarantee(entry > N_words, "Should be in logarithmic region"); | |
302 } | |
303 size_t backskip = BlockOffsetArray::entry_to_cards_back(entry); | |
304 size_t landing_card = c - backskip; | |
305 guarantee(landing_card >= (start_card - 1), "Inv"); | |
306 if (landing_card >= start_card) { | |
307 guarantee(_array->offset_array(landing_card) <= entry, "monotonicity"); | |
308 } else { | |
309 guarantee(landing_card == start_card - 1, "Tautology"); | |
310 guarantee(_array->offset_array(landing_card) <= N_words, "Offset value"); | |
311 } | |
312 } | |
313 } | |
314 | |
315 // The range [blk_start, blk_end) represents a single contiguous block | |
316 // of storage; modify the block offset table to represent this | |
317 // information; Right-open interval: [blk_start, blk_end) | |
318 // NOTE: this method does _not_ adjust _unallocated_block. | |
319 void | |
320 G1BlockOffsetArray::single_block(HeapWord* blk_start, HeapWord* blk_end) { | |
321 do_block_internal(blk_start, blk_end, Action_single); | |
322 } | |
323 | |
324 // Mark the BOT such that if [blk_start, blk_end) straddles a card | |
325 // boundary, the card following the first such boundary is marked | |
326 // with the appropriate offset. | |
327 // NOTE: this method does _not_ adjust _unallocated_block or | |
328 // any cards subsequent to the first one. | |
329 void | |
330 G1BlockOffsetArray::mark_block(HeapWord* blk_start, HeapWord* blk_end) { | |
331 do_block_internal(blk_start, blk_end, Action_mark); | |
332 } | |
333 | |
334 void G1BlockOffsetArray::join_blocks(HeapWord* blk1, HeapWord* blk2) { | |
335 HeapWord* blk1_start = Universe::heap()->block_start(blk1); | |
336 HeapWord* blk2_start = Universe::heap()->block_start(blk2); | |
337 assert(blk1 == blk1_start && blk2 == blk2_start, | |
338 "Must be block starts."); | |
339 assert(blk1 + _sp->block_size(blk1) == blk2, "Must be contiguous."); | |
340 size_t blk1_start_index = _array->index_for(blk1); | |
341 size_t blk2_start_index = _array->index_for(blk2); | |
342 assert(blk1_start_index <= blk2_start_index, "sanity"); | |
343 HeapWord* blk2_card_start = _array->address_for_index(blk2_start_index); | |
344 if (blk2 == blk2_card_start) { | |
345 // blk2 starts a card. Does blk1 start on the prevous card, or futher | |
346 // back? | |
347 assert(blk1_start_index < blk2_start_index, "must be lower card."); | |
348 if (blk1_start_index + 1 == blk2_start_index) { | |
349 // previous card; new value for blk2 card is size of blk1. | |
350 _array->set_offset_array(blk2_start_index, (u_char) _sp->block_size(blk1)); | |
351 } else { | |
352 // Earlier card; go back a card. | |
353 _array->set_offset_array(blk2_start_index, N_words); | |
354 } | |
355 } else { | |
356 // blk2 does not start a card. Does it cross a card? If not, nothing | |
357 // to do. | |
358 size_t blk2_end_index = | |
359 _array->index_for(blk2 + _sp->block_size(blk2) - 1); | |
360 assert(blk2_end_index >= blk2_start_index, "sanity"); | |
361 if (blk2_end_index > blk2_start_index) { | |
362 // Yes, it crosses a card. The value for the next card must change. | |
363 if (blk1_start_index + 1 == blk2_start_index) { | |
364 // previous card; new value for second blk2 card is size of blk1. | |
365 _array->set_offset_array(blk2_start_index + 1, | |
366 (u_char) _sp->block_size(blk1)); | |
367 } else { | |
368 // Earlier card; go back a card. | |
369 _array->set_offset_array(blk2_start_index + 1, N_words); | |
370 } | |
371 } | |
372 } | |
373 } | |
374 | |
375 HeapWord* G1BlockOffsetArray::block_start_unsafe(const void* addr) { | |
376 assert(_bottom <= addr && addr < _end, | |
377 "addr must be covered by this Array"); | |
378 // Must read this exactly once because it can be modified by parallel | |
379 // allocation. | |
380 HeapWord* ub = _unallocated_block; | |
381 if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) { | |
382 assert(ub < _end, "tautology (see above)"); | |
383 return ub; | |
384 } | |
385 // Otherwise, find the block start using the table. | |
386 HeapWord* q = block_at_or_preceding(addr, false, 0); | |
387 return forward_to_block_containing_addr(q, addr); | |
388 } | |
389 | |
390 // This duplicates a little code from the above: unavoidable. | |
391 HeapWord* | |
392 G1BlockOffsetArray::block_start_unsafe_const(const void* addr) const { | |
393 assert(_bottom <= addr && addr < _end, | |
394 "addr must be covered by this Array"); | |
395 // Must read this exactly once because it can be modified by parallel | |
396 // allocation. | |
397 HeapWord* ub = _unallocated_block; | |
398 if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) { | |
399 assert(ub < _end, "tautology (see above)"); | |
400 return ub; | |
401 } | |
402 // Otherwise, find the block start using the table. | |
403 HeapWord* q = block_at_or_preceding(addr, false, 0); | |
404 HeapWord* n = q + _sp->block_size(q); | |
405 return forward_to_block_containing_addr_const(q, n, addr); | |
406 } | |
407 | |
408 | |
409 HeapWord* | |
410 G1BlockOffsetArray::forward_to_block_containing_addr_slow(HeapWord* q, | |
411 HeapWord* n, | |
412 const void* addr) { | |
413 // We're not in the normal case. We need to handle an important subcase | |
414 // here: LAB allocation. An allocation previously recorded in the | |
415 // offset table was actually a lab allocation, and was divided into | |
416 // several objects subsequently. Fix this situation as we answer the | |
417 // query, by updating entries as we cross them. | |
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419 // If the fist object's end q is at the card boundary. Start refining |
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420 // with the corresponding card (the value of the entry will be basically |
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421 // set to 0). If the object crosses the boundary -- start from the next card. |
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422 size_t next_index = _array->index_for(n) + !_array->is_card_boundary(n); |
342 | 423 HeapWord* next_boundary = _array->address_for_index(next_index); |
424 if (csp() != NULL) { | |
425 if (addr >= csp()->top()) return csp()->top(); | |
426 while (next_boundary < addr) { | |
427 while (n <= next_boundary) { | |
428 q = n; | |
429 oop obj = oop(q); | |
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430 if (obj->klass_or_null() == NULL) return q; |
342 | 431 n += obj->size(); |
432 } | |
433 assert(q <= next_boundary && n > next_boundary, "Consequence of loop"); | |
434 // [q, n) is the block that crosses the boundary. | |
435 alloc_block_work2(&next_boundary, &next_index, q, n); | |
436 } | |
437 } else { | |
438 while (next_boundary < addr) { | |
439 while (n <= next_boundary) { | |
440 q = n; | |
441 oop obj = oop(q); | |
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442 if (obj->klass_or_null() == NULL) return q; |
342 | 443 n += _sp->block_size(q); |
444 } | |
445 assert(q <= next_boundary && n > next_boundary, "Consequence of loop"); | |
446 // [q, n) is the block that crosses the boundary. | |
447 alloc_block_work2(&next_boundary, &next_index, q, n); | |
448 } | |
449 } | |
450 return forward_to_block_containing_addr_const(q, n, addr); | |
451 } | |
452 | |
453 HeapWord* G1BlockOffsetArray::block_start_careful(const void* addr) const { | |
454 assert(_array->offset_array(0) == 0, "objects can't cross covered areas"); | |
455 | |
456 assert(_bottom <= addr && addr < _end, | |
457 "addr must be covered by this Array"); | |
458 // Must read this exactly once because it can be modified by parallel | |
459 // allocation. | |
460 HeapWord* ub = _unallocated_block; | |
461 if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) { | |
462 assert(ub < _end, "tautology (see above)"); | |
463 return ub; | |
464 } | |
465 | |
466 // Otherwise, find the block start using the table, but taking | |
467 // care (cf block_start_unsafe() above) not to parse any objects/blocks | |
468 // on the cards themsleves. | |
469 size_t index = _array->index_for(addr); | |
470 assert(_array->address_for_index(index) == addr, | |
471 "arg should be start of card"); | |
472 | |
473 HeapWord* q = (HeapWord*)addr; | |
474 uint offset; | |
475 do { | |
476 offset = _array->offset_array(index--); | |
477 q -= offset; | |
478 } while (offset == N_words); | |
479 assert(q <= addr, "block start should be to left of arg"); | |
480 return q; | |
481 } | |
482 | |
483 // Note that the committed size of the covered space may have changed, | |
484 // so the table size might also wish to change. | |
485 void G1BlockOffsetArray::resize(size_t new_word_size) { | |
486 HeapWord* new_end = _bottom + new_word_size; | |
487 if (_end < new_end && !init_to_zero()) { | |
488 // verify that the old and new boundaries are also card boundaries | |
489 assert(_array->is_card_boundary(_end), | |
490 "_end not a card boundary"); | |
491 assert(_array->is_card_boundary(new_end), | |
492 "new _end would not be a card boundary"); | |
493 // set all the newly added cards | |
494 _array->set_offset_array(_end, new_end, N_words); | |
495 } | |
496 _end = new_end; // update _end | |
497 } | |
498 | |
499 void G1BlockOffsetArray::set_region(MemRegion mr) { | |
500 _bottom = mr.start(); | |
501 _end = mr.end(); | |
502 } | |
503 | |
504 // | |
505 // threshold_ | |
506 // | _index_ | |
507 // v v | |
508 // +-------+-------+-------+-------+-------+ | |
509 // | i-1 | i | i+1 | i+2 | i+3 | | |
510 // +-------+-------+-------+-------+-------+ | |
511 // ( ^ ] | |
512 // block-start | |
513 // | |
514 void G1BlockOffsetArray::alloc_block_work2(HeapWord** threshold_, size_t* index_, | |
515 HeapWord* blk_start, HeapWord* blk_end) { | |
516 // For efficiency, do copy-in/copy-out. | |
517 HeapWord* threshold = *threshold_; | |
518 size_t index = *index_; | |
519 | |
520 assert(blk_start != NULL && blk_end > blk_start, | |
521 "phantom block"); | |
522 assert(blk_end > threshold, "should be past threshold"); | |
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523 assert(blk_start <= threshold, "blk_start should be at or before threshold"); |
342 | 524 assert(pointer_delta(threshold, blk_start) <= N_words, |
525 "offset should be <= BlockOffsetSharedArray::N"); | |
526 assert(Universe::heap()->is_in_reserved(blk_start), | |
527 "reference must be into the heap"); | |
528 assert(Universe::heap()->is_in_reserved(blk_end-1), | |
529 "limit must be within the heap"); | |
530 assert(threshold == _array->_reserved.start() + index*N_words, | |
531 "index must agree with threshold"); | |
532 | |
533 DEBUG_ONLY(size_t orig_index = index;) | |
534 | |
535 // Mark the card that holds the offset into the block. Note | |
536 // that _next_offset_index and _next_offset_threshold are not | |
537 // updated until the end of this method. | |
538 _array->set_offset_array(index, threshold, blk_start); | |
539 | |
540 // We need to now mark the subsequent cards that this blk spans. | |
541 | |
542 // Index of card on which blk ends. | |
543 size_t end_index = _array->index_for(blk_end - 1); | |
544 | |
545 // Are there more cards left to be updated? | |
546 if (index + 1 <= end_index) { | |
547 HeapWord* rem_st = _array->address_for_index(index + 1); | |
548 // Calculate rem_end this way because end_index | |
549 // may be the last valid index in the covered region. | |
550 HeapWord* rem_end = _array->address_for_index(end_index) + N_words; | |
551 set_remainder_to_point_to_start(rem_st, rem_end); | |
552 } | |
553 | |
554 index = end_index + 1; | |
555 // Calculate threshold_ this way because end_index | |
556 // may be the last valid index in the covered region. | |
557 threshold = _array->address_for_index(end_index) + N_words; | |
558 assert(threshold >= blk_end, "Incorrect offset threshold"); | |
559 | |
560 // index_ and threshold_ updated here. | |
561 *threshold_ = threshold; | |
562 *index_ = index; | |
563 | |
564 #ifdef ASSERT | |
565 // The offset can be 0 if the block starts on a boundary. That | |
566 // is checked by an assertion above. | |
567 size_t start_index = _array->index_for(blk_start); | |
568 HeapWord* boundary = _array->address_for_index(start_index); | |
569 assert((_array->offset_array(orig_index) == 0 && | |
570 blk_start == boundary) || | |
571 (_array->offset_array(orig_index) > 0 && | |
572 _array->offset_array(orig_index) <= N_words), | |
573 "offset array should have been set"); | |
574 for (size_t j = orig_index + 1; j <= end_index; j++) { | |
575 assert(_array->offset_array(j) > 0 && | |
576 _array->offset_array(j) <= | |
577 (u_char) (N_words+BlockOffsetArray::N_powers-1), | |
578 "offset array should have been set"); | |
579 } | |
580 #endif | |
581 } | |
582 | |
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583 void |
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584 G1BlockOffsetArray::set_for_starts_humongous(HeapWord* new_end) { |
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585 assert(_end == new_end, "_end should have already been updated"); |
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586 |
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587 // The first BOT entry should have offset 0. |
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588 _array->set_offset_array(_array->index_for(_bottom), 0); |
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589 // The rest should point to the first one. |
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590 set_remainder_to_point_to_start(_bottom + N_words, new_end); |
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591 } |
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592 |
342 | 593 ////////////////////////////////////////////////////////////////////// |
594 // G1BlockOffsetArrayContigSpace | |
595 ////////////////////////////////////////////////////////////////////// | |
596 | |
597 HeapWord* | |
598 G1BlockOffsetArrayContigSpace::block_start_unsafe(const void* addr) { | |
599 assert(_bottom <= addr && addr < _end, | |
600 "addr must be covered by this Array"); | |
601 HeapWord* q = block_at_or_preceding(addr, true, _next_offset_index-1); | |
602 return forward_to_block_containing_addr(q, addr); | |
603 } | |
604 | |
605 HeapWord* | |
606 G1BlockOffsetArrayContigSpace:: | |
607 block_start_unsafe_const(const void* addr) const { | |
608 assert(_bottom <= addr && addr < _end, | |
609 "addr must be covered by this Array"); | |
610 HeapWord* q = block_at_or_preceding(addr, true, _next_offset_index-1); | |
611 HeapWord* n = q + _sp->block_size(q); | |
612 return forward_to_block_containing_addr_const(q, n, addr); | |
613 } | |
614 | |
615 G1BlockOffsetArrayContigSpace:: | |
616 G1BlockOffsetArrayContigSpace(G1BlockOffsetSharedArray* array, | |
617 MemRegion mr) : | |
618 G1BlockOffsetArray(array, mr, true) | |
619 { | |
620 _next_offset_threshold = NULL; | |
621 _next_offset_index = 0; | |
622 } | |
623 | |
624 HeapWord* G1BlockOffsetArrayContigSpace::initialize_threshold() { | |
625 assert(!Universe::heap()->is_in_reserved(_array->_offset_array), | |
626 "just checking"); | |
627 _next_offset_index = _array->index_for(_bottom); | |
628 _next_offset_index++; | |
629 _next_offset_threshold = | |
630 _array->address_for_index(_next_offset_index); | |
631 return _next_offset_threshold; | |
632 } | |
633 | |
634 void G1BlockOffsetArrayContigSpace::zero_bottom_entry() { | |
635 assert(!Universe::heap()->is_in_reserved(_array->_offset_array), | |
636 "just checking"); | |
637 size_t bottom_index = _array->index_for(_bottom); | |
638 assert(_array->address_for_index(bottom_index) == _bottom, | |
639 "Precondition of call"); | |
640 _array->set_offset_array(bottom_index, 0); | |
641 } | |
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642 |
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643 void |
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644 G1BlockOffsetArrayContigSpace::set_for_starts_humongous(HeapWord* new_end) { |
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645 G1BlockOffsetArray::set_for_starts_humongous(new_end); |
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646 |
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647 // Make sure _next_offset_threshold and _next_offset_index point to new_end. |
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648 _next_offset_threshold = new_end; |
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649 _next_offset_index = _array->index_for(new_end); |
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650 } |