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annotate src/share/vm/memory/blockOffsetTable.cpp @ 5334:ecc2b68344de
turn off priority compilation queue
author | Lukas Stadler <lukas.stadler@jku.at> |
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date | Wed, 02 May 2012 12:59:59 +0200 |
parents | 8cbcd406c42e |
children | d2a62e0f25eb |
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0 | 1 /* |
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2 * Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved. |
0 | 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. |
0 | 22 * |
23 */ | |
24 | |
1972 | 25 #include "precompiled.hpp" |
26 #include "gc_interface/collectedHeap.inline.hpp" | |
27 #include "memory/blockOffsetTable.inline.hpp" | |
28 #include "memory/iterator.hpp" | |
29 #include "memory/space.inline.hpp" | |
30 #include "memory/universe.hpp" | |
31 #include "oops/oop.inline.hpp" | |
32 #include "runtime/java.hpp" | |
0 | 33 |
34 ////////////////////////////////////////////////////////////////////// | |
35 // BlockOffsetSharedArray | |
36 ////////////////////////////////////////////////////////////////////// | |
37 | |
38 BlockOffsetSharedArray::BlockOffsetSharedArray(MemRegion reserved, | |
39 size_t init_word_size): | |
40 _reserved(reserved), _end(NULL) | |
41 { | |
42 size_t size = compute_size(reserved.word_size()); | |
43 ReservedSpace rs(size); | |
44 if (!rs.is_reserved()) { | |
45 vm_exit_during_initialization("Could not reserve enough space for heap offset array"); | |
46 } | |
47 if (!_vs.initialize(rs, 0)) { | |
48 vm_exit_during_initialization("Could not reserve enough space for heap offset array"); | |
49 } | |
50 _offset_array = (u_char*)_vs.low_boundary(); | |
51 resize(init_word_size); | |
52 if (TraceBlockOffsetTable) { | |
53 gclog_or_tty->print_cr("BlockOffsetSharedArray::BlockOffsetSharedArray: "); | |
54 gclog_or_tty->print_cr(" " | |
55 " rs.base(): " INTPTR_FORMAT | |
56 " rs.size(): " INTPTR_FORMAT | |
57 " rs end(): " INTPTR_FORMAT, | |
58 rs.base(), rs.size(), rs.base() + rs.size()); | |
59 gclog_or_tty->print_cr(" " | |
60 " _vs.low_boundary(): " INTPTR_FORMAT | |
61 " _vs.high_boundary(): " INTPTR_FORMAT, | |
62 _vs.low_boundary(), | |
63 _vs.high_boundary()); | |
64 } | |
65 } | |
66 | |
67 void BlockOffsetSharedArray::resize(size_t new_word_size) { | |
68 assert(new_word_size <= _reserved.word_size(), "Resize larger than reserved"); | |
69 size_t new_size = compute_size(new_word_size); | |
70 size_t old_size = _vs.committed_size(); | |
71 size_t delta; | |
72 char* high = _vs.high(); | |
73 _end = _reserved.start() + new_word_size; | |
74 if (new_size > old_size) { | |
75 delta = ReservedSpace::page_align_size_up(new_size - old_size); | |
76 assert(delta > 0, "just checking"); | |
77 if (!_vs.expand_by(delta)) { | |
78 // Do better than this for Merlin | |
79 vm_exit_out_of_memory(delta, "offset table expansion"); | |
80 } | |
81 assert(_vs.high() == high + delta, "invalid expansion"); | |
82 } else { | |
83 delta = ReservedSpace::page_align_size_down(old_size - new_size); | |
84 if (delta == 0) return; | |
85 _vs.shrink_by(delta); | |
86 assert(_vs.high() == high - delta, "invalid expansion"); | |
87 } | |
88 } | |
89 | |
90 bool BlockOffsetSharedArray::is_card_boundary(HeapWord* p) const { | |
91 assert(p >= _reserved.start(), "just checking"); | |
92 size_t delta = pointer_delta(p, _reserved.start()); | |
93 return (delta & right_n_bits(LogN_words)) == (size_t)NoBits; | |
94 } | |
95 | |
96 | |
97 void BlockOffsetSharedArray::serialize(SerializeOopClosure* soc, | |
98 HeapWord* start, HeapWord* end) { | |
99 assert(_offset_array[0] == 0, "objects can't cross covered areas"); | |
100 assert(start <= end, "bad address range"); | |
101 size_t start_index = index_for(start); | |
102 size_t end_index = index_for(end-1)+1; | |
103 soc->do_region(&_offset_array[start_index], | |
104 (end_index - start_index) * sizeof(_offset_array[0])); | |
105 } | |
106 | |
107 ////////////////////////////////////////////////////////////////////// | |
108 // BlockOffsetArray | |
109 ////////////////////////////////////////////////////////////////////// | |
110 | |
111 BlockOffsetArray::BlockOffsetArray(BlockOffsetSharedArray* array, | |
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112 MemRegion mr, bool init_to_zero_) : |
0 | 113 BlockOffsetTable(mr.start(), mr.end()), |
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114 _array(array) |
0 | 115 { |
116 assert(_bottom <= _end, "arguments out of order"); | |
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117 set_init_to_zero(init_to_zero_); |
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118 if (!init_to_zero_) { |
0 | 119 // initialize cards to point back to mr.start() |
120 set_remainder_to_point_to_start(mr.start() + N_words, mr.end()); | |
121 _array->set_offset_array(0, 0); // set first card to 0 | |
122 } | |
123 } | |
124 | |
125 | |
126 // The arguments follow the normal convention of denoting | |
127 // a right-open interval: [start, end) | |
128 void | |
129 BlockOffsetArray:: | |
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130 set_remainder_to_point_to_start(HeapWord* start, HeapWord* end, bool reducing) { |
0 | 131 |
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132 check_reducing_assertion(reducing); |
0 | 133 if (start >= end) { |
134 // The start address is equal to the end address (or to | |
135 // the right of the end address) so there are not cards | |
136 // that need to be updated.. | |
137 return; | |
138 } | |
139 | |
140 // Write the backskip value for each region. | |
141 // | |
142 // offset | |
143 // card 2nd 3rd | |
144 // | +- 1st | | | |
145 // v v v v | |
146 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+- | |
147 // |x|0|0|0|0|0|0|0|1|1|1|1|1|1| ... |1|1|1|1|2|2|2|2|2|2| ... | |
148 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+- | |
149 // 11 19 75 | |
150 // 12 | |
151 // | |
152 // offset card is the card that points to the start of an object | |
153 // x - offset value of offset card | |
154 // 1st - start of first logarithmic region | |
155 // 0 corresponds to logarithmic value N_words + 0 and 2**(3 * 0) = 1 | |
156 // 2nd - start of second logarithmic region | |
157 // 1 corresponds to logarithmic value N_words + 1 and 2**(3 * 1) = 8 | |
158 // 3rd - start of third logarithmic region | |
159 // 2 corresponds to logarithmic value N_words + 2 and 2**(3 * 2) = 64 | |
160 // | |
161 // integer below the block offset entry is an example of | |
162 // the index of the entry | |
163 // | |
164 // Given an address, | |
165 // Find the index for the address | |
166 // Find the block offset table entry | |
167 // Convert the entry to a back slide | |
168 // (e.g., with today's, offset = 0x81 => | |
169 // back slip = 2**(3*(0x81 - N_words)) = 2**3) = 8 | |
170 // Move back N (e.g., 8) entries and repeat with the | |
171 // value of the new entry | |
172 // | |
173 size_t start_card = _array->index_for(start); | |
174 size_t end_card = _array->index_for(end-1); | |
175 assert(start ==_array->address_for_index(start_card), "Precondition"); | |
176 assert(end ==_array->address_for_index(end_card)+N_words, "Precondition"); | |
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177 set_remainder_to_point_to_start_incl(start_card, end_card, reducing); // closed interval |
0 | 178 } |
179 | |
180 | |
181 // Unlike the normal convention in this code, the argument here denotes | |
182 // a closed, inclusive interval: [start_card, end_card], cf set_remainder_to_point_to_start() | |
183 // above. | |
184 void | |
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185 BlockOffsetArray::set_remainder_to_point_to_start_incl(size_t start_card, size_t end_card, bool reducing) { |
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186 |
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187 check_reducing_assertion(reducing); |
0 | 188 if (start_card > end_card) { |
189 return; | |
190 } | |
191 assert(start_card > _array->index_for(_bottom), "Cannot be first card"); | |
192 assert(_array->offset_array(start_card-1) <= N_words, | |
193 "Offset card has an unexpected value"); | |
194 size_t start_card_for_region = start_card; | |
195 u_char offset = max_jubyte; | |
342 | 196 for (int i = 0; i < N_powers; i++) { |
0 | 197 // -1 so that the the card with the actual offset is counted. Another -1 |
198 // so that the reach ends in this region and not at the start | |
199 // of the next. | |
200 size_t reach = start_card - 1 + (power_to_cards_back(i+1) - 1); | |
201 offset = N_words + i; | |
202 if (reach >= end_card) { | |
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203 _array->set_offset_array(start_card_for_region, end_card, offset, reducing); |
0 | 204 start_card_for_region = reach + 1; |
205 break; | |
206 } | |
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207 _array->set_offset_array(start_card_for_region, reach, offset, reducing); |
0 | 208 start_card_for_region = reach + 1; |
209 } | |
210 assert(start_card_for_region > end_card, "Sanity check"); | |
211 DEBUG_ONLY(check_all_cards(start_card, end_card);) | |
212 } | |
213 | |
214 // The card-interval [start_card, end_card] is a closed interval; this | |
215 // is an expensive check -- use with care and only under protection of | |
216 // suitable flag. | |
217 void BlockOffsetArray::check_all_cards(size_t start_card, size_t end_card) const { | |
218 | |
219 if (end_card < start_card) { | |
220 return; | |
221 } | |
222 guarantee(_array->offset_array(start_card) == N_words, "Wrong value in second card"); | |
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223 u_char last_entry = N_words; |
0 | 224 for (size_t c = start_card + 1; c <= end_card; c++ /* yeah! */) { |
225 u_char entry = _array->offset_array(c); | |
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226 guarantee(entry >= last_entry, "Monotonicity"); |
0 | 227 if (c - start_card > power_to_cards_back(1)) { |
228 guarantee(entry > N_words, "Should be in logarithmic region"); | |
229 } | |
230 size_t backskip = entry_to_cards_back(entry); | |
231 size_t landing_card = c - backskip; | |
232 guarantee(landing_card >= (start_card - 1), "Inv"); | |
233 if (landing_card >= start_card) { | |
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234 guarantee(_array->offset_array(landing_card) <= entry, "Monotonicity"); |
0 | 235 } else { |
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236 guarantee(landing_card == (start_card - 1), "Tautology"); |
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237 // Note that N_words is the maximum offset value |
0 | 238 guarantee(_array->offset_array(landing_card) <= N_words, "Offset value"); |
239 } | |
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240 last_entry = entry; // remember for monotonicity test |
0 | 241 } |
242 } | |
243 | |
244 | |
245 void | |
246 BlockOffsetArray::alloc_block(HeapWord* blk_start, HeapWord* blk_end) { | |
247 assert(blk_start != NULL && blk_end > blk_start, | |
248 "phantom block"); | |
249 single_block(blk_start, blk_end); | |
250 } | |
251 | |
252 // Action_mark - update the BOT for the block [blk_start, blk_end). | |
253 // Current typical use is for splitting a block. | |
254 // Action_single - udpate the BOT for an allocation. | |
255 // Action_verify - BOT verification. | |
256 void | |
257 BlockOffsetArray::do_block_internal(HeapWord* blk_start, | |
258 HeapWord* blk_end, | |
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259 Action action, bool reducing) { |
0 | 260 assert(Universe::heap()->is_in_reserved(blk_start), |
261 "reference must be into the heap"); | |
262 assert(Universe::heap()->is_in_reserved(blk_end-1), | |
263 "limit must be within the heap"); | |
264 // This is optimized to make the test fast, assuming we only rarely | |
265 // cross boundaries. | |
266 uintptr_t end_ui = (uintptr_t)(blk_end - 1); | |
267 uintptr_t start_ui = (uintptr_t)blk_start; | |
268 // Calculate the last card boundary preceding end of blk | |
269 intptr_t boundary_before_end = (intptr_t)end_ui; | |
270 clear_bits(boundary_before_end, right_n_bits(LogN)); | |
271 if (start_ui <= (uintptr_t)boundary_before_end) { | |
272 // blk starts at or crosses a boundary | |
273 // Calculate index of card on which blk begins | |
274 size_t start_index = _array->index_for(blk_start); | |
275 // Index of card on which blk ends | |
276 size_t end_index = _array->index_for(blk_end - 1); | |
277 // Start address of card on which blk begins | |
278 HeapWord* boundary = _array->address_for_index(start_index); | |
279 assert(boundary <= blk_start, "blk should start at or after boundary"); | |
280 if (blk_start != boundary) { | |
281 // blk starts strictly after boundary | |
282 // adjust card boundary and start_index forward to next card | |
283 boundary += N_words; | |
284 start_index++; | |
285 } | |
286 assert(start_index <= end_index, "monotonicity of index_for()"); | |
287 assert(boundary <= (HeapWord*)boundary_before_end, "tautology"); | |
288 switch (action) { | |
289 case Action_mark: { | |
290 if (init_to_zero()) { | |
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291 _array->set_offset_array(start_index, boundary, blk_start, reducing); |
0 | 292 break; |
293 } // Else fall through to the next case | |
294 } | |
295 case Action_single: { | |
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296 _array->set_offset_array(start_index, boundary, blk_start, reducing); |
0 | 297 // We have finished marking the "offset card". We need to now |
298 // mark the subsequent cards that this blk spans. | |
299 if (start_index < end_index) { | |
300 HeapWord* rem_st = _array->address_for_index(start_index) + N_words; | |
301 HeapWord* rem_end = _array->address_for_index(end_index) + N_words; | |
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302 set_remainder_to_point_to_start(rem_st, rem_end, reducing); |
0 | 303 } |
304 break; | |
305 } | |
306 case Action_check: { | |
307 _array->check_offset_array(start_index, boundary, blk_start); | |
308 // We have finished checking the "offset card". We need to now | |
309 // check the subsequent cards that this blk spans. | |
310 check_all_cards(start_index + 1, end_index); | |
311 break; | |
312 } | |
313 default: | |
314 ShouldNotReachHere(); | |
315 } | |
316 } | |
317 } | |
318 | |
319 // The range [blk_start, blk_end) represents a single contiguous block | |
320 // of storage; modify the block offset table to represent this | |
321 // information; Right-open interval: [blk_start, blk_end) | |
322 // NOTE: this method does _not_ adjust _unallocated_block. | |
323 void | |
324 BlockOffsetArray::single_block(HeapWord* blk_start, | |
325 HeapWord* blk_end) { | |
326 do_block_internal(blk_start, blk_end, Action_single); | |
327 } | |
328 | |
329 void BlockOffsetArray::verify() const { | |
330 // For each entry in the block offset table, verify that | |
331 // the entry correctly finds the start of an object at the | |
332 // first address covered by the block or to the left of that | |
333 // first address. | |
334 | |
335 size_t next_index = 1; | |
336 size_t last_index = last_active_index(); | |
337 | |
338 // Use for debugging. Initialize to NULL to distinguish the | |
339 // first iteration through the while loop. | |
340 HeapWord* last_p = NULL; | |
341 HeapWord* last_start = NULL; | |
342 oop last_o = NULL; | |
343 | |
344 while (next_index <= last_index) { | |
345 // Use an address past the start of the address for | |
346 // the entry. | |
347 HeapWord* p = _array->address_for_index(next_index) + 1; | |
348 if (p >= _end) { | |
349 // That's all of the allocated block table. | |
350 return; | |
351 } | |
352 // block_start() asserts that start <= p. | |
353 HeapWord* start = block_start(p); | |
354 // First check if the start is an allocated block and only | |
355 // then if it is a valid object. | |
356 oop o = oop(start); | |
357 assert(!Universe::is_fully_initialized() || | |
358 _sp->is_free_block(start) || | |
359 o->is_oop_or_null(), "Bad object was found"); | |
360 next_index++; | |
361 last_p = p; | |
362 last_start = start; | |
363 last_o = o; | |
364 } | |
365 } | |
366 | |
367 ////////////////////////////////////////////////////////////////////// | |
368 // BlockOffsetArrayNonContigSpace | |
369 ////////////////////////////////////////////////////////////////////// | |
370 | |
371 // The block [blk_start, blk_end) has been allocated; | |
372 // adjust the block offset table to represent this information; | |
373 // NOTE: Clients of BlockOffsetArrayNonContigSpace: consider using | |
374 // the somewhat more lightweight split_block() or | |
375 // (when init_to_zero()) mark_block() wherever possible. | |
376 // right-open interval: [blk_start, blk_end) | |
377 void | |
378 BlockOffsetArrayNonContigSpace::alloc_block(HeapWord* blk_start, | |
379 HeapWord* blk_end) { | |
380 assert(blk_start != NULL && blk_end > blk_start, | |
381 "phantom block"); | |
382 single_block(blk_start, blk_end); | |
383 allocated(blk_start, blk_end); | |
384 } | |
385 | |
386 // Adjust BOT to show that a previously whole block has been split | |
387 // into two. We verify the BOT for the first part (prefix) and | |
388 // update the BOT for the second part (suffix). | |
389 // blk is the start of the block | |
390 // blk_size is the size of the original block | |
391 // left_blk_size is the size of the first part of the split | |
392 void BlockOffsetArrayNonContigSpace::split_block(HeapWord* blk, | |
393 size_t blk_size, | |
394 size_t left_blk_size) { | |
395 // Verify that the BOT shows [blk, blk + blk_size) to be one block. | |
396 verify_single_block(blk, blk_size); | |
397 // Update the BOT to indicate that [blk + left_blk_size, blk + blk_size) | |
398 // is one single block. | |
399 assert(blk_size > 0, "Should be positive"); | |
400 assert(left_blk_size > 0, "Should be positive"); | |
401 assert(left_blk_size < blk_size, "Not a split"); | |
402 | |
403 // Start addresses of prefix block and suffix block. | |
404 HeapWord* pref_addr = blk; | |
405 HeapWord* suff_addr = blk + left_blk_size; | |
406 HeapWord* end_addr = blk + blk_size; | |
407 | |
408 // Indices for starts of prefix block and suffix block. | |
409 size_t pref_index = _array->index_for(pref_addr); | |
410 if (_array->address_for_index(pref_index) != pref_addr) { | |
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411 // pref_addr does not begin pref_index |
0 | 412 pref_index++; |
413 } | |
414 | |
415 size_t suff_index = _array->index_for(suff_addr); | |
416 if (_array->address_for_index(suff_index) != suff_addr) { | |
417 // suff_addr does not begin suff_index | |
418 suff_index++; | |
419 } | |
420 | |
421 // Definition: A block B, denoted [B_start, B_end) __starts__ | |
422 // a card C, denoted [C_start, C_end), where C_start and C_end | |
423 // are the heap addresses that card C covers, iff | |
424 // B_start <= C_start < B_end. | |
425 // | |
426 // We say that a card C "is started by" a block B, iff | |
427 // B "starts" C. | |
428 // | |
429 // Note that the cardinality of the set of cards {C} | |
430 // started by a block B can be 0, 1, or more. | |
431 // | |
432 // Below, pref_index and suff_index are, respectively, the | |
433 // first (least) card indices that the prefix and suffix of | |
434 // the split start; end_index is one more than the index of | |
435 // the last (greatest) card that blk starts. | |
436 size_t end_index = _array->index_for(end_addr - 1) + 1; | |
437 | |
438 // Calculate the # cards that the prefix and suffix affect. | |
439 size_t num_pref_cards = suff_index - pref_index; | |
440 | |
441 size_t num_suff_cards = end_index - suff_index; | |
442 // Change the cards that need changing | |
443 if (num_suff_cards > 0) { | |
444 HeapWord* boundary = _array->address_for_index(suff_index); | |
445 // Set the offset card for suffix block | |
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446 _array->set_offset_array(suff_index, boundary, suff_addr, true /* reducing */); |
0 | 447 // Change any further cards that need changing in the suffix |
448 if (num_pref_cards > 0) { | |
449 if (num_pref_cards >= num_suff_cards) { | |
450 // Unilaterally fix all of the suffix cards: closed card | |
451 // index interval in args below. | |
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452 set_remainder_to_point_to_start_incl(suff_index + 1, end_index - 1, true /* reducing */); |
0 | 453 } else { |
454 // Unilaterally fix the first (num_pref_cards - 1) following | |
455 // the "offset card" in the suffix block. | |
456 set_remainder_to_point_to_start_incl(suff_index + 1, | |
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457 suff_index + num_pref_cards - 1, true /* reducing */); |
0 | 458 // Fix the appropriate cards in the remainder of the |
459 // suffix block -- these are the last num_pref_cards | |
460 // cards in each power block of the "new" range plumbed | |
461 // from suff_addr. | |
462 bool more = true; | |
463 uint i = 1; | |
464 while (more && (i < N_powers)) { | |
465 size_t back_by = power_to_cards_back(i); | |
466 size_t right_index = suff_index + back_by - 1; | |
467 size_t left_index = right_index - num_pref_cards + 1; | |
468 if (right_index >= end_index - 1) { // last iteration | |
469 right_index = end_index - 1; | |
470 more = false; | |
471 } | |
472 if (back_by > num_pref_cards) { | |
473 // Fill in the remainder of this "power block", if it | |
474 // is non-null. | |
475 if (left_index <= right_index) { | |
476 _array->set_offset_array(left_index, right_index, | |
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477 N_words + i - 1, true /* reducing */); |
0 | 478 } else { |
479 more = false; // we are done | |
480 } | |
481 i++; | |
482 break; | |
483 } | |
484 i++; | |
485 } | |
486 while (more && (i < N_powers)) { | |
487 size_t back_by = power_to_cards_back(i); | |
488 size_t right_index = suff_index + back_by - 1; | |
489 size_t left_index = right_index - num_pref_cards + 1; | |
490 if (right_index >= end_index - 1) { // last iteration | |
491 right_index = end_index - 1; | |
492 if (left_index > right_index) { | |
493 break; | |
494 } | |
495 more = false; | |
496 } | |
497 assert(left_index <= right_index, "Error"); | |
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498 _array->set_offset_array(left_index, right_index, N_words + i - 1, true /* reducing */); |
0 | 499 i++; |
500 } | |
501 } | |
502 } // else no more cards to fix in suffix | |
503 } // else nothing needs to be done | |
504 // Verify that we did the right thing | |
505 verify_single_block(pref_addr, left_blk_size); | |
506 verify_single_block(suff_addr, blk_size - left_blk_size); | |
507 } | |
508 | |
509 | |
510 // Mark the BOT such that if [blk_start, blk_end) straddles a card | |
511 // boundary, the card following the first such boundary is marked | |
512 // with the appropriate offset. | |
513 // NOTE: this method does _not_ adjust _unallocated_block or | |
514 // any cards subsequent to the first one. | |
515 void | |
516 BlockOffsetArrayNonContigSpace::mark_block(HeapWord* blk_start, | |
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517 HeapWord* blk_end, bool reducing) { |
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518 do_block_internal(blk_start, blk_end, Action_mark, reducing); |
0 | 519 } |
520 | |
521 HeapWord* BlockOffsetArrayNonContigSpace::block_start_unsafe( | |
522 const void* addr) const { | |
523 assert(_array->offset_array(0) == 0, "objects can't cross covered areas"); | |
524 assert(_bottom <= addr && addr < _end, | |
525 "addr must be covered by this Array"); | |
526 // Must read this exactly once because it can be modified by parallel | |
527 // allocation. | |
528 HeapWord* ub = _unallocated_block; | |
529 if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) { | |
530 assert(ub < _end, "tautology (see above)"); | |
531 return ub; | |
532 } | |
533 | |
534 // Otherwise, find the block start using the table. | |
535 size_t index = _array->index_for(addr); | |
536 HeapWord* q = _array->address_for_index(index); | |
537 | |
538 uint offset = _array->offset_array(index); // Extend u_char to uint. | |
539 while (offset >= N_words) { | |
540 // The excess of the offset from N_words indicates a power of Base | |
541 // to go back by. | |
542 size_t n_cards_back = entry_to_cards_back(offset); | |
543 q -= (N_words * n_cards_back); | |
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544 assert(q >= _sp->bottom(), |
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545 err_msg("q = " PTR_FORMAT " crossed below bottom = " PTR_FORMAT, |
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546 q, _sp->bottom())); |
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547 assert(q < _sp->end(), |
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548 err_msg("q = " PTR_FORMAT " crossed above end = " PTR_FORMAT, |
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549 q, _sp->end())); |
0 | 550 index -= n_cards_back; |
551 offset = _array->offset_array(index); | |
552 } | |
553 assert(offset < N_words, "offset too large"); | |
554 index--; | |
555 q -= offset; | |
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556 assert(q >= _sp->bottom(), |
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557 err_msg("q = " PTR_FORMAT " crossed below bottom = " PTR_FORMAT, |
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558 q, _sp->bottom())); |
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559 assert(q < _sp->end(), |
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560 err_msg("q = " PTR_FORMAT " crossed above end = " PTR_FORMAT, |
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561 q, _sp->end())); |
0 | 562 HeapWord* n = q; |
563 | |
564 while (n <= addr) { | |
565 debug_only(HeapWord* last = q); // for debugging | |
566 q = n; | |
567 n += _sp->block_size(n); | |
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568 assert(n > q, |
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569 err_msg("Looping at n = " PTR_FORMAT " with last = " PTR_FORMAT"," |
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570 " while querying blk_start(" PTR_FORMAT ")" |
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571 " on _sp = [" PTR_FORMAT "," PTR_FORMAT ")", |
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572 n, last, addr, _sp->bottom(), _sp->end())); |
0 | 573 } |
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574 assert(q <= addr, |
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575 err_msg("wrong order for current (" INTPTR_FORMAT ")" " <= arg (" INTPTR_FORMAT ")", |
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576 q, addr)); |
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577 assert(addr <= n, |
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578 err_msg("wrong order for arg (" INTPTR_FORMAT ") <= next (" INTPTR_FORMAT ")", |
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579 addr, n)); |
0 | 580 return q; |
581 } | |
582 | |
583 HeapWord* BlockOffsetArrayNonContigSpace::block_start_careful( | |
584 const void* addr) const { | |
585 assert(_array->offset_array(0) == 0, "objects can't cross covered areas"); | |
586 | |
587 assert(_bottom <= addr && addr < _end, | |
588 "addr must be covered by this Array"); | |
589 // Must read this exactly once because it can be modified by parallel | |
590 // allocation. | |
591 HeapWord* ub = _unallocated_block; | |
592 if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) { | |
593 assert(ub < _end, "tautology (see above)"); | |
594 return ub; | |
595 } | |
596 | |
597 // Otherwise, find the block start using the table, but taking | |
598 // care (cf block_start_unsafe() above) not to parse any objects/blocks | |
599 // on the cards themsleves. | |
600 size_t index = _array->index_for(addr); | |
601 assert(_array->address_for_index(index) == addr, | |
602 "arg should be start of card"); | |
603 | |
604 HeapWord* q = (HeapWord*)addr; | |
605 uint offset; | |
606 do { | |
607 offset = _array->offset_array(index); | |
608 if (offset < N_words) { | |
609 q -= offset; | |
610 } else { | |
611 size_t n_cards_back = entry_to_cards_back(offset); | |
612 q -= (n_cards_back * N_words); | |
613 index -= n_cards_back; | |
614 } | |
615 } while (offset >= N_words); | |
616 assert(q <= addr, "block start should be to left of arg"); | |
617 return q; | |
618 } | |
619 | |
620 #ifndef PRODUCT | |
621 // Verification & debugging - ensure that the offset table reflects the fact | |
622 // that the block [blk_start, blk_end) or [blk, blk + size) is a | |
623 // single block of storage. NOTE: can't const this because of | |
624 // call to non-const do_block_internal() below. | |
625 void BlockOffsetArrayNonContigSpace::verify_single_block( | |
626 HeapWord* blk_start, HeapWord* blk_end) { | |
627 if (VerifyBlockOffsetArray) { | |
628 do_block_internal(blk_start, blk_end, Action_check); | |
629 } | |
630 } | |
631 | |
632 void BlockOffsetArrayNonContigSpace::verify_single_block( | |
633 HeapWord* blk, size_t size) { | |
634 verify_single_block(blk, blk + size); | |
635 } | |
636 | |
637 // Verify that the given block is before _unallocated_block | |
638 void BlockOffsetArrayNonContigSpace::verify_not_unallocated( | |
639 HeapWord* blk_start, HeapWord* blk_end) const { | |
640 if (BlockOffsetArrayUseUnallocatedBlock) { | |
641 assert(blk_start < blk_end, "Block inconsistency?"); | |
642 assert(blk_end <= _unallocated_block, "_unallocated_block problem"); | |
643 } | |
644 } | |
645 | |
646 void BlockOffsetArrayNonContigSpace::verify_not_unallocated( | |
647 HeapWord* blk, size_t size) const { | |
648 verify_not_unallocated(blk, blk + size); | |
649 } | |
650 #endif // PRODUCT | |
651 | |
652 size_t BlockOffsetArrayNonContigSpace::last_active_index() const { | |
653 if (_unallocated_block == _bottom) { | |
654 return 0; | |
655 } else { | |
656 return _array->index_for(_unallocated_block - 1); | |
657 } | |
658 } | |
659 | |
660 ////////////////////////////////////////////////////////////////////// | |
661 // BlockOffsetArrayContigSpace | |
662 ////////////////////////////////////////////////////////////////////// | |
663 | |
664 HeapWord* BlockOffsetArrayContigSpace::block_start_unsafe(const void* addr) const { | |
665 assert(_array->offset_array(0) == 0, "objects can't cross covered areas"); | |
666 | |
667 // Otherwise, find the block start using the table. | |
668 assert(_bottom <= addr && addr < _end, | |
669 "addr must be covered by this Array"); | |
670 size_t index = _array->index_for(addr); | |
671 // We must make sure that the offset table entry we use is valid. If | |
672 // "addr" is past the end, start at the last known one and go forward. | |
673 index = MIN2(index, _next_offset_index-1); | |
674 HeapWord* q = _array->address_for_index(index); | |
675 | |
676 uint offset = _array->offset_array(index); // Extend u_char to uint. | |
677 while (offset > N_words) { | |
678 // The excess of the offset from N_words indicates a power of Base | |
679 // to go back by. | |
680 size_t n_cards_back = entry_to_cards_back(offset); | |
681 q -= (N_words * n_cards_back); | |
682 assert(q >= _sp->bottom(), "Went below bottom!"); | |
683 index -= n_cards_back; | |
684 offset = _array->offset_array(index); | |
685 } | |
686 while (offset == N_words) { | |
687 assert(q >= _sp->bottom(), "Went below bottom!"); | |
688 q -= N_words; | |
689 index--; | |
690 offset = _array->offset_array(index); | |
691 } | |
692 assert(offset < N_words, "offset too large"); | |
693 q -= offset; | |
694 HeapWord* n = q; | |
695 | |
696 while (n <= addr) { | |
697 debug_only(HeapWord* last = q); // for debugging | |
698 q = n; | |
699 n += _sp->block_size(n); | |
700 } | |
701 assert(q <= addr, "wrong order for current and arg"); | |
702 assert(addr <= n, "wrong order for arg and next"); | |
703 return q; | |
704 } | |
705 | |
706 // | |
707 // _next_offset_threshold | |
708 // | _next_offset_index | |
709 // v v | |
710 // +-------+-------+-------+-------+-------+ | |
711 // | i-1 | i | i+1 | i+2 | i+3 | | |
712 // +-------+-------+-------+-------+-------+ | |
713 // ( ^ ] | |
714 // block-start | |
715 // | |
716 | |
717 void BlockOffsetArrayContigSpace::alloc_block_work(HeapWord* blk_start, | |
718 HeapWord* blk_end) { | |
719 assert(blk_start != NULL && blk_end > blk_start, | |
720 "phantom block"); | |
721 assert(blk_end > _next_offset_threshold, | |
722 "should be past threshold"); | |
723 assert(blk_start <= _next_offset_threshold, | |
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724 "blk_start should be at or before threshold"); |
0 | 725 assert(pointer_delta(_next_offset_threshold, blk_start) <= N_words, |
726 "offset should be <= BlockOffsetSharedArray::N"); | |
727 assert(Universe::heap()->is_in_reserved(blk_start), | |
728 "reference must be into the heap"); | |
729 assert(Universe::heap()->is_in_reserved(blk_end-1), | |
730 "limit must be within the heap"); | |
731 assert(_next_offset_threshold == | |
732 _array->_reserved.start() + _next_offset_index*N_words, | |
733 "index must agree with threshold"); | |
734 | |
735 debug_only(size_t orig_next_offset_index = _next_offset_index;) | |
736 | |
737 // Mark the card that holds the offset into the block. Note | |
738 // that _next_offset_index and _next_offset_threshold are not | |
739 // updated until the end of this method. | |
740 _array->set_offset_array(_next_offset_index, | |
741 _next_offset_threshold, | |
742 blk_start); | |
743 | |
744 // We need to now mark the subsequent cards that this blk spans. | |
745 | |
746 // Index of card on which blk ends. | |
747 size_t end_index = _array->index_for(blk_end - 1); | |
748 | |
749 // Are there more cards left to be updated? | |
750 if (_next_offset_index + 1 <= end_index) { | |
751 HeapWord* rem_st = _array->address_for_index(_next_offset_index + 1); | |
752 // Calculate rem_end this way because end_index | |
753 // may be the last valid index in the covered region. | |
754 HeapWord* rem_end = _array->address_for_index(end_index) + N_words; | |
755 set_remainder_to_point_to_start(rem_st, rem_end); | |
756 } | |
757 | |
758 // _next_offset_index and _next_offset_threshold updated here. | |
759 _next_offset_index = end_index + 1; | |
760 // Calculate _next_offset_threshold this way because end_index | |
761 // may be the last valid index in the covered region. | |
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762 _next_offset_threshold = _array->address_for_index(end_index) + N_words; |
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763 assert(_next_offset_threshold >= blk_end, "Incorrect offset threshold"); |
0 | 764 |
765 #ifdef ASSERT | |
766 // The offset can be 0 if the block starts on a boundary. That | |
767 // is checked by an assertion above. | |
768 size_t start_index = _array->index_for(blk_start); | |
769 HeapWord* boundary = _array->address_for_index(start_index); | |
770 assert((_array->offset_array(orig_next_offset_index) == 0 && | |
771 blk_start == boundary) || | |
772 (_array->offset_array(orig_next_offset_index) > 0 && | |
773 _array->offset_array(orig_next_offset_index) <= N_words), | |
774 "offset array should have been set"); | |
775 for (size_t j = orig_next_offset_index + 1; j <= end_index; j++) { | |
776 assert(_array->offset_array(j) > 0 && | |
777 _array->offset_array(j) <= (u_char) (N_words+N_powers-1), | |
778 "offset array should have been set"); | |
779 } | |
780 #endif | |
781 } | |
782 | |
783 HeapWord* BlockOffsetArrayContigSpace::initialize_threshold() { | |
784 assert(!Universe::heap()->is_in_reserved(_array->_offset_array), | |
785 "just checking"); | |
786 _next_offset_index = _array->index_for(_bottom); | |
787 _next_offset_index++; | |
788 _next_offset_threshold = | |
789 _array->address_for_index(_next_offset_index); | |
790 return _next_offset_threshold; | |
791 } | |
792 | |
793 void BlockOffsetArrayContigSpace::zero_bottom_entry() { | |
794 assert(!Universe::heap()->is_in_reserved(_array->_offset_array), | |
795 "just checking"); | |
796 size_t bottom_index = _array->index_for(_bottom); | |
797 _array->set_offset_array(bottom_index, 0); | |
798 } | |
799 | |
800 | |
801 void BlockOffsetArrayContigSpace::serialize(SerializeOopClosure* soc) { | |
802 if (soc->reading()) { | |
803 // Null these values so that the serializer won't object to updating them. | |
804 _next_offset_threshold = NULL; | |
805 _next_offset_index = 0; | |
806 } | |
807 soc->do_ptr(&_next_offset_threshold); | |
808 soc->do_size_t(&_next_offset_index); | |
809 } | |
810 | |
811 size_t BlockOffsetArrayContigSpace::last_active_index() const { | |
812 size_t result = _next_offset_index - 1; | |
813 return result >= 0 ? result : 0; | |
814 } |