Mercurial > hg > graal-compiler
annotate src/share/vm/memory/blockOffsetTable.cpp @ 1711:a6bff45449bc
6973570: OrderAccess::storestore() scales poorly on multi-socket x64 and sparc: cache-line ping-ponging
Summary: volatile store to static variable removed in favour of a volatile store to stack to avoid excessive cache coherency traffic; verified that the volatile store is not elided by any of our current compilers.
Reviewed-by: dholmes, dice, jcoomes, kvn
author | ysr |
---|---|
date | Tue, 10 Aug 2010 14:53:35 -0700 |
parents | c18cbe5936b8 |
children | be3f9c242c9d |
rev | line source |
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0 | 1 /* |
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2 * Copyright (c) 2000, 2006, Oracle and/or its affiliates. All rights reserved. |
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4 * | |
5 * This code is free software; you can redistribute it and/or modify it | |
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7 * published by the Free Software Foundation. | |
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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). | |
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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 | |
25 # include "incls/_precompiled.incl" | |
26 # include "incls/_blockOffsetTable.cpp.incl" | |
27 | |
28 ////////////////////////////////////////////////////////////////////// | |
29 // BlockOffsetSharedArray | |
30 ////////////////////////////////////////////////////////////////////// | |
31 | |
32 BlockOffsetSharedArray::BlockOffsetSharedArray(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(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("BlockOffsetSharedArray::BlockOffsetSharedArray: "); | |
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 BlockOffsetSharedArray::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 } else { | |
77 delta = ReservedSpace::page_align_size_down(old_size - new_size); | |
78 if (delta == 0) return; | |
79 _vs.shrink_by(delta); | |
80 assert(_vs.high() == high - delta, "invalid expansion"); | |
81 } | |
82 } | |
83 | |
84 bool BlockOffsetSharedArray::is_card_boundary(HeapWord* p) const { | |
85 assert(p >= _reserved.start(), "just checking"); | |
86 size_t delta = pointer_delta(p, _reserved.start()); | |
87 return (delta & right_n_bits(LogN_words)) == (size_t)NoBits; | |
88 } | |
89 | |
90 | |
91 void BlockOffsetSharedArray::serialize(SerializeOopClosure* soc, | |
92 HeapWord* start, HeapWord* end) { | |
93 assert(_offset_array[0] == 0, "objects can't cross covered areas"); | |
94 assert(start <= end, "bad address range"); | |
95 size_t start_index = index_for(start); | |
96 size_t end_index = index_for(end-1)+1; | |
97 soc->do_region(&_offset_array[start_index], | |
98 (end_index - start_index) * sizeof(_offset_array[0])); | |
99 } | |
100 | |
101 ////////////////////////////////////////////////////////////////////// | |
102 // BlockOffsetArray | |
103 ////////////////////////////////////////////////////////////////////// | |
104 | |
105 BlockOffsetArray::BlockOffsetArray(BlockOffsetSharedArray* array, | |
106 MemRegion mr, bool init_to_zero) : | |
107 BlockOffsetTable(mr.start(), mr.end()), | |
108 _array(array), | |
109 _init_to_zero(init_to_zero) | |
110 { | |
111 assert(_bottom <= _end, "arguments out of order"); | |
112 if (!_init_to_zero) { | |
113 // initialize cards to point back to mr.start() | |
114 set_remainder_to_point_to_start(mr.start() + N_words, mr.end()); | |
115 _array->set_offset_array(0, 0); // set first card to 0 | |
116 } | |
117 } | |
118 | |
119 | |
120 // The arguments follow the normal convention of denoting | |
121 // a right-open interval: [start, end) | |
122 void | |
123 BlockOffsetArray:: | |
124 set_remainder_to_point_to_start(HeapWord* start, HeapWord* end) { | |
125 | |
126 if (start >= end) { | |
127 // The start address is equal to the end address (or to | |
128 // the right of the end address) so there are not cards | |
129 // that need to be updated.. | |
130 return; | |
131 } | |
132 | |
133 // Write the backskip value for each region. | |
134 // | |
135 // offset | |
136 // card 2nd 3rd | |
137 // | +- 1st | | | |
138 // v v v v | |
139 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+- | |
140 // |x|0|0|0|0|0|0|0|1|1|1|1|1|1| ... |1|1|1|1|2|2|2|2|2|2| ... | |
141 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+- | |
142 // 11 19 75 | |
143 // 12 | |
144 // | |
145 // offset card is the card that points to the start of an object | |
146 // x - offset value of offset card | |
147 // 1st - start of first logarithmic region | |
148 // 0 corresponds to logarithmic value N_words + 0 and 2**(3 * 0) = 1 | |
149 // 2nd - start of second logarithmic region | |
150 // 1 corresponds to logarithmic value N_words + 1 and 2**(3 * 1) = 8 | |
151 // 3rd - start of third logarithmic region | |
152 // 2 corresponds to logarithmic value N_words + 2 and 2**(3 * 2) = 64 | |
153 // | |
154 // integer below the block offset entry is an example of | |
155 // the index of the entry | |
156 // | |
157 // Given an address, | |
158 // Find the index for the address | |
159 // Find the block offset table entry | |
160 // Convert the entry to a back slide | |
161 // (e.g., with today's, offset = 0x81 => | |
162 // back slip = 2**(3*(0x81 - N_words)) = 2**3) = 8 | |
163 // Move back N (e.g., 8) entries and repeat with the | |
164 // value of the new entry | |
165 // | |
166 size_t start_card = _array->index_for(start); | |
167 size_t end_card = _array->index_for(end-1); | |
168 assert(start ==_array->address_for_index(start_card), "Precondition"); | |
169 assert(end ==_array->address_for_index(end_card)+N_words, "Precondition"); | |
170 set_remainder_to_point_to_start_incl(start_card, end_card); // closed interval | |
171 } | |
172 | |
173 | |
174 // Unlike the normal convention in this code, the argument here denotes | |
175 // a closed, inclusive interval: [start_card, end_card], cf set_remainder_to_point_to_start() | |
176 // above. | |
177 void | |
178 BlockOffsetArray::set_remainder_to_point_to_start_incl(size_t start_card, size_t end_card) { | |
179 if (start_card > end_card) { | |
180 return; | |
181 } | |
182 assert(start_card > _array->index_for(_bottom), "Cannot be first card"); | |
183 assert(_array->offset_array(start_card-1) <= N_words, | |
184 "Offset card has an unexpected value"); | |
185 size_t start_card_for_region = start_card; | |
186 u_char offset = max_jubyte; | |
342 | 187 for (int i = 0; i < N_powers; i++) { |
0 | 188 // -1 so that the the card with the actual offset is counted. Another -1 |
189 // so that the reach ends in this region and not at the start | |
190 // of the next. | |
191 size_t reach = start_card - 1 + (power_to_cards_back(i+1) - 1); | |
192 offset = N_words + i; | |
193 if (reach >= end_card) { | |
194 _array->set_offset_array(start_card_for_region, end_card, offset); | |
195 start_card_for_region = reach + 1; | |
196 break; | |
197 } | |
198 _array->set_offset_array(start_card_for_region, reach, offset); | |
199 start_card_for_region = reach + 1; | |
200 } | |
201 assert(start_card_for_region > end_card, "Sanity check"); | |
202 DEBUG_ONLY(check_all_cards(start_card, end_card);) | |
203 } | |
204 | |
205 // The card-interval [start_card, end_card] is a closed interval; this | |
206 // is an expensive check -- use with care and only under protection of | |
207 // suitable flag. | |
208 void BlockOffsetArray::check_all_cards(size_t start_card, size_t end_card) const { | |
209 | |
210 if (end_card < start_card) { | |
211 return; | |
212 } | |
213 guarantee(_array->offset_array(start_card) == N_words, "Wrong value in second card"); | |
214 for (size_t c = start_card + 1; c <= end_card; c++ /* yeah! */) { | |
215 u_char entry = _array->offset_array(c); | |
216 if (c - start_card > power_to_cards_back(1)) { | |
217 guarantee(entry > N_words, "Should be in logarithmic region"); | |
218 } | |
219 size_t backskip = entry_to_cards_back(entry); | |
220 size_t landing_card = c - backskip; | |
221 guarantee(landing_card >= (start_card - 1), "Inv"); | |
222 if (landing_card >= start_card) { | |
223 guarantee(_array->offset_array(landing_card) <= entry, "monotonicity"); | |
224 } else { | |
225 guarantee(landing_card == start_card - 1, "Tautology"); | |
226 guarantee(_array->offset_array(landing_card) <= N_words, "Offset value"); | |
227 } | |
228 } | |
229 } | |
230 | |
231 | |
232 void | |
233 BlockOffsetArray::alloc_block(HeapWord* blk_start, HeapWord* blk_end) { | |
234 assert(blk_start != NULL && blk_end > blk_start, | |
235 "phantom block"); | |
236 single_block(blk_start, blk_end); | |
237 } | |
238 | |
239 // Action_mark - update the BOT for the block [blk_start, blk_end). | |
240 // Current typical use is for splitting a block. | |
241 // Action_single - udpate the BOT for an allocation. | |
242 // Action_verify - BOT verification. | |
243 void | |
244 BlockOffsetArray::do_block_internal(HeapWord* blk_start, | |
245 HeapWord* blk_end, | |
246 Action action) { | |
247 assert(Universe::heap()->is_in_reserved(blk_start), | |
248 "reference must be into the heap"); | |
249 assert(Universe::heap()->is_in_reserved(blk_end-1), | |
250 "limit must be within the heap"); | |
251 // This is optimized to make the test fast, assuming we only rarely | |
252 // cross boundaries. | |
253 uintptr_t end_ui = (uintptr_t)(blk_end - 1); | |
254 uintptr_t start_ui = (uintptr_t)blk_start; | |
255 // Calculate the last card boundary preceding end of blk | |
256 intptr_t boundary_before_end = (intptr_t)end_ui; | |
257 clear_bits(boundary_before_end, right_n_bits(LogN)); | |
258 if (start_ui <= (uintptr_t)boundary_before_end) { | |
259 // blk starts at or crosses a boundary | |
260 // Calculate index of card on which blk begins | |
261 size_t start_index = _array->index_for(blk_start); | |
262 // Index of card on which blk ends | |
263 size_t end_index = _array->index_for(blk_end - 1); | |
264 // Start address of card on which blk begins | |
265 HeapWord* boundary = _array->address_for_index(start_index); | |
266 assert(boundary <= blk_start, "blk should start at or after boundary"); | |
267 if (blk_start != boundary) { | |
268 // blk starts strictly after boundary | |
269 // adjust card boundary and start_index forward to next card | |
270 boundary += N_words; | |
271 start_index++; | |
272 } | |
273 assert(start_index <= end_index, "monotonicity of index_for()"); | |
274 assert(boundary <= (HeapWord*)boundary_before_end, "tautology"); | |
275 switch (action) { | |
276 case Action_mark: { | |
277 if (init_to_zero()) { | |
278 _array->set_offset_array(start_index, boundary, blk_start); | |
279 break; | |
280 } // Else fall through to the next case | |
281 } | |
282 case Action_single: { | |
283 _array->set_offset_array(start_index, boundary, blk_start); | |
284 // We have finished marking the "offset card". We need to now | |
285 // mark the subsequent cards that this blk spans. | |
286 if (start_index < end_index) { | |
287 HeapWord* rem_st = _array->address_for_index(start_index) + N_words; | |
288 HeapWord* rem_end = _array->address_for_index(end_index) + N_words; | |
289 set_remainder_to_point_to_start(rem_st, rem_end); | |
290 } | |
291 break; | |
292 } | |
293 case Action_check: { | |
294 _array->check_offset_array(start_index, boundary, blk_start); | |
295 // We have finished checking the "offset card". We need to now | |
296 // check the subsequent cards that this blk spans. | |
297 check_all_cards(start_index + 1, end_index); | |
298 break; | |
299 } | |
300 default: | |
301 ShouldNotReachHere(); | |
302 } | |
303 } | |
304 } | |
305 | |
306 // The range [blk_start, blk_end) represents a single contiguous block | |
307 // of storage; modify the block offset table to represent this | |
308 // information; Right-open interval: [blk_start, blk_end) | |
309 // NOTE: this method does _not_ adjust _unallocated_block. | |
310 void | |
311 BlockOffsetArray::single_block(HeapWord* blk_start, | |
312 HeapWord* blk_end) { | |
313 do_block_internal(blk_start, blk_end, Action_single); | |
314 } | |
315 | |
316 void BlockOffsetArray::verify() const { | |
317 // For each entry in the block offset table, verify that | |
318 // the entry correctly finds the start of an object at the | |
319 // first address covered by the block or to the left of that | |
320 // first address. | |
321 | |
322 size_t next_index = 1; | |
323 size_t last_index = last_active_index(); | |
324 | |
325 // Use for debugging. Initialize to NULL to distinguish the | |
326 // first iteration through the while loop. | |
327 HeapWord* last_p = NULL; | |
328 HeapWord* last_start = NULL; | |
329 oop last_o = NULL; | |
330 | |
331 while (next_index <= last_index) { | |
332 // Use an address past the start of the address for | |
333 // the entry. | |
334 HeapWord* p = _array->address_for_index(next_index) + 1; | |
335 if (p >= _end) { | |
336 // That's all of the allocated block table. | |
337 return; | |
338 } | |
339 // block_start() asserts that start <= p. | |
340 HeapWord* start = block_start(p); | |
341 // First check if the start is an allocated block and only | |
342 // then if it is a valid object. | |
343 oop o = oop(start); | |
344 assert(!Universe::is_fully_initialized() || | |
345 _sp->is_free_block(start) || | |
346 o->is_oop_or_null(), "Bad object was found"); | |
347 next_index++; | |
348 last_p = p; | |
349 last_start = start; | |
350 last_o = o; | |
351 } | |
352 } | |
353 | |
354 ////////////////////////////////////////////////////////////////////// | |
355 // BlockOffsetArrayNonContigSpace | |
356 ////////////////////////////////////////////////////////////////////// | |
357 | |
358 // The block [blk_start, blk_end) has been allocated; | |
359 // adjust the block offset table to represent this information; | |
360 // NOTE: Clients of BlockOffsetArrayNonContigSpace: consider using | |
361 // the somewhat more lightweight split_block() or | |
362 // (when init_to_zero()) mark_block() wherever possible. | |
363 // right-open interval: [blk_start, blk_end) | |
364 void | |
365 BlockOffsetArrayNonContigSpace::alloc_block(HeapWord* blk_start, | |
366 HeapWord* blk_end) { | |
367 assert(blk_start != NULL && blk_end > blk_start, | |
368 "phantom block"); | |
369 single_block(blk_start, blk_end); | |
370 allocated(blk_start, blk_end); | |
371 } | |
372 | |
373 // Adjust BOT to show that a previously whole block has been split | |
374 // into two. We verify the BOT for the first part (prefix) and | |
375 // update the BOT for the second part (suffix). | |
376 // blk is the start of the block | |
377 // blk_size is the size of the original block | |
378 // left_blk_size is the size of the first part of the split | |
379 void BlockOffsetArrayNonContigSpace::split_block(HeapWord* blk, | |
380 size_t blk_size, | |
381 size_t left_blk_size) { | |
382 // Verify that the BOT shows [blk, blk + blk_size) to be one block. | |
383 verify_single_block(blk, blk_size); | |
384 // Update the BOT to indicate that [blk + left_blk_size, blk + blk_size) | |
385 // is one single block. | |
386 assert(blk_size > 0, "Should be positive"); | |
387 assert(left_blk_size > 0, "Should be positive"); | |
388 assert(left_blk_size < blk_size, "Not a split"); | |
389 | |
390 // Start addresses of prefix block and suffix block. | |
391 HeapWord* pref_addr = blk; | |
392 HeapWord* suff_addr = blk + left_blk_size; | |
393 HeapWord* end_addr = blk + blk_size; | |
394 | |
395 // Indices for starts of prefix block and suffix block. | |
396 size_t pref_index = _array->index_for(pref_addr); | |
397 if (_array->address_for_index(pref_index) != pref_addr) { | |
398 // pref_addr deos not begin pref_index | |
399 pref_index++; | |
400 } | |
401 | |
402 size_t suff_index = _array->index_for(suff_addr); | |
403 if (_array->address_for_index(suff_index) != suff_addr) { | |
404 // suff_addr does not begin suff_index | |
405 suff_index++; | |
406 } | |
407 | |
408 // Definition: A block B, denoted [B_start, B_end) __starts__ | |
409 // a card C, denoted [C_start, C_end), where C_start and C_end | |
410 // are the heap addresses that card C covers, iff | |
411 // B_start <= C_start < B_end. | |
412 // | |
413 // We say that a card C "is started by" a block B, iff | |
414 // B "starts" C. | |
415 // | |
416 // Note that the cardinality of the set of cards {C} | |
417 // started by a block B can be 0, 1, or more. | |
418 // | |
419 // Below, pref_index and suff_index are, respectively, the | |
420 // first (least) card indices that the prefix and suffix of | |
421 // the split start; end_index is one more than the index of | |
422 // the last (greatest) card that blk starts. | |
423 size_t end_index = _array->index_for(end_addr - 1) + 1; | |
424 | |
425 // Calculate the # cards that the prefix and suffix affect. | |
426 size_t num_pref_cards = suff_index - pref_index; | |
427 | |
428 size_t num_suff_cards = end_index - suff_index; | |
429 // Change the cards that need changing | |
430 if (num_suff_cards > 0) { | |
431 HeapWord* boundary = _array->address_for_index(suff_index); | |
432 // Set the offset card for suffix block | |
433 _array->set_offset_array(suff_index, boundary, suff_addr); | |
434 // Change any further cards that need changing in the suffix | |
435 if (num_pref_cards > 0) { | |
436 if (num_pref_cards >= num_suff_cards) { | |
437 // Unilaterally fix all of the suffix cards: closed card | |
438 // index interval in args below. | |
439 set_remainder_to_point_to_start_incl(suff_index + 1, end_index - 1); | |
440 } else { | |
441 // Unilaterally fix the first (num_pref_cards - 1) following | |
442 // the "offset card" in the suffix block. | |
443 set_remainder_to_point_to_start_incl(suff_index + 1, | |
444 suff_index + num_pref_cards - 1); | |
445 // Fix the appropriate cards in the remainder of the | |
446 // suffix block -- these are the last num_pref_cards | |
447 // cards in each power block of the "new" range plumbed | |
448 // from suff_addr. | |
449 bool more = true; | |
450 uint i = 1; | |
451 while (more && (i < N_powers)) { | |
452 size_t back_by = power_to_cards_back(i); | |
453 size_t right_index = suff_index + back_by - 1; | |
454 size_t left_index = right_index - num_pref_cards + 1; | |
455 if (right_index >= end_index - 1) { // last iteration | |
456 right_index = end_index - 1; | |
457 more = false; | |
458 } | |
459 if (back_by > num_pref_cards) { | |
460 // Fill in the remainder of this "power block", if it | |
461 // is non-null. | |
462 if (left_index <= right_index) { | |
463 _array->set_offset_array(left_index, right_index, | |
464 N_words + i - 1); | |
465 } else { | |
466 more = false; // we are done | |
467 } | |
468 i++; | |
469 break; | |
470 } | |
471 i++; | |
472 } | |
473 while (more && (i < N_powers)) { | |
474 size_t back_by = power_to_cards_back(i); | |
475 size_t right_index = suff_index + back_by - 1; | |
476 size_t left_index = right_index - num_pref_cards + 1; | |
477 if (right_index >= end_index - 1) { // last iteration | |
478 right_index = end_index - 1; | |
479 if (left_index > right_index) { | |
480 break; | |
481 } | |
482 more = false; | |
483 } | |
484 assert(left_index <= right_index, "Error"); | |
485 _array->set_offset_array(left_index, right_index, N_words + i - 1); | |
486 i++; | |
487 } | |
488 } | |
489 } // else no more cards to fix in suffix | |
490 } // else nothing needs to be done | |
491 // Verify that we did the right thing | |
492 verify_single_block(pref_addr, left_blk_size); | |
493 verify_single_block(suff_addr, blk_size - left_blk_size); | |
494 } | |
495 | |
496 | |
497 // Mark the BOT such that if [blk_start, blk_end) straddles a card | |
498 // boundary, the card following the first such boundary is marked | |
499 // with the appropriate offset. | |
500 // NOTE: this method does _not_ adjust _unallocated_block or | |
501 // any cards subsequent to the first one. | |
502 void | |
503 BlockOffsetArrayNonContigSpace::mark_block(HeapWord* blk_start, | |
504 HeapWord* blk_end) { | |
505 do_block_internal(blk_start, blk_end, Action_mark); | |
506 } | |
507 | |
508 HeapWord* BlockOffsetArrayNonContigSpace::block_start_unsafe( | |
509 const void* addr) const { | |
510 assert(_array->offset_array(0) == 0, "objects can't cross covered areas"); | |
511 | |
512 assert(_bottom <= addr && addr < _end, | |
513 "addr must be covered by this Array"); | |
514 // Must read this exactly once because it can be modified by parallel | |
515 // allocation. | |
516 HeapWord* ub = _unallocated_block; | |
517 if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) { | |
518 assert(ub < _end, "tautology (see above)"); | |
519 return ub; | |
520 } | |
521 | |
522 // Otherwise, find the block start using the table. | |
523 size_t index = _array->index_for(addr); | |
524 HeapWord* q = _array->address_for_index(index); | |
525 | |
526 uint offset = _array->offset_array(index); // Extend u_char to uint. | |
527 while (offset >= N_words) { | |
528 // The excess of the offset from N_words indicates a power of Base | |
529 // to go back by. | |
530 size_t n_cards_back = entry_to_cards_back(offset); | |
531 q -= (N_words * n_cards_back); | |
532 assert(q >= _sp->bottom(), "Went below bottom!"); | |
533 index -= n_cards_back; | |
534 offset = _array->offset_array(index); | |
535 } | |
536 assert(offset < N_words, "offset too large"); | |
537 index--; | |
538 q -= offset; | |
539 HeapWord* n = q; | |
540 | |
541 while (n <= addr) { | |
542 debug_only(HeapWord* last = q); // for debugging | |
543 q = n; | |
544 n += _sp->block_size(n); | |
545 } | |
546 assert(q <= addr, "wrong order for current and arg"); | |
547 assert(addr <= n, "wrong order for arg and next"); | |
548 return q; | |
549 } | |
550 | |
551 HeapWord* BlockOffsetArrayNonContigSpace::block_start_careful( | |
552 const void* addr) const { | |
553 assert(_array->offset_array(0) == 0, "objects can't cross covered areas"); | |
554 | |
555 assert(_bottom <= addr && addr < _end, | |
556 "addr must be covered by this Array"); | |
557 // Must read this exactly once because it can be modified by parallel | |
558 // allocation. | |
559 HeapWord* ub = _unallocated_block; | |
560 if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) { | |
561 assert(ub < _end, "tautology (see above)"); | |
562 return ub; | |
563 } | |
564 | |
565 // Otherwise, find the block start using the table, but taking | |
566 // care (cf block_start_unsafe() above) not to parse any objects/blocks | |
567 // on the cards themsleves. | |
568 size_t index = _array->index_for(addr); | |
569 assert(_array->address_for_index(index) == addr, | |
570 "arg should be start of card"); | |
571 | |
572 HeapWord* q = (HeapWord*)addr; | |
573 uint offset; | |
574 do { | |
575 offset = _array->offset_array(index); | |
576 if (offset < N_words) { | |
577 q -= offset; | |
578 } else { | |
579 size_t n_cards_back = entry_to_cards_back(offset); | |
580 q -= (n_cards_back * N_words); | |
581 index -= n_cards_back; | |
582 } | |
583 } while (offset >= N_words); | |
584 assert(q <= addr, "block start should be to left of arg"); | |
585 return q; | |
586 } | |
587 | |
588 #ifndef PRODUCT | |
589 // Verification & debugging - ensure that the offset table reflects the fact | |
590 // that the block [blk_start, blk_end) or [blk, blk + size) is a | |
591 // single block of storage. NOTE: can't const this because of | |
592 // call to non-const do_block_internal() below. | |
593 void BlockOffsetArrayNonContigSpace::verify_single_block( | |
594 HeapWord* blk_start, HeapWord* blk_end) { | |
595 if (VerifyBlockOffsetArray) { | |
596 do_block_internal(blk_start, blk_end, Action_check); | |
597 } | |
598 } | |
599 | |
600 void BlockOffsetArrayNonContigSpace::verify_single_block( | |
601 HeapWord* blk, size_t size) { | |
602 verify_single_block(blk, blk + size); | |
603 } | |
604 | |
605 // Verify that the given block is before _unallocated_block | |
606 void BlockOffsetArrayNonContigSpace::verify_not_unallocated( | |
607 HeapWord* blk_start, HeapWord* blk_end) const { | |
608 if (BlockOffsetArrayUseUnallocatedBlock) { | |
609 assert(blk_start < blk_end, "Block inconsistency?"); | |
610 assert(blk_end <= _unallocated_block, "_unallocated_block problem"); | |
611 } | |
612 } | |
613 | |
614 void BlockOffsetArrayNonContigSpace::verify_not_unallocated( | |
615 HeapWord* blk, size_t size) const { | |
616 verify_not_unallocated(blk, blk + size); | |
617 } | |
618 #endif // PRODUCT | |
619 | |
620 size_t BlockOffsetArrayNonContigSpace::last_active_index() const { | |
621 if (_unallocated_block == _bottom) { | |
622 return 0; | |
623 } else { | |
624 return _array->index_for(_unallocated_block - 1); | |
625 } | |
626 } | |
627 | |
628 ////////////////////////////////////////////////////////////////////// | |
629 // BlockOffsetArrayContigSpace | |
630 ////////////////////////////////////////////////////////////////////// | |
631 | |
632 HeapWord* BlockOffsetArrayContigSpace::block_start_unsafe(const void* addr) const { | |
633 assert(_array->offset_array(0) == 0, "objects can't cross covered areas"); | |
634 | |
635 // Otherwise, find the block start using the table. | |
636 assert(_bottom <= addr && addr < _end, | |
637 "addr must be covered by this Array"); | |
638 size_t index = _array->index_for(addr); | |
639 // We must make sure that the offset table entry we use is valid. If | |
640 // "addr" is past the end, start at the last known one and go forward. | |
641 index = MIN2(index, _next_offset_index-1); | |
642 HeapWord* q = _array->address_for_index(index); | |
643 | |
644 uint offset = _array->offset_array(index); // Extend u_char to uint. | |
645 while (offset > N_words) { | |
646 // The excess of the offset from N_words indicates a power of Base | |
647 // to go back by. | |
648 size_t n_cards_back = entry_to_cards_back(offset); | |
649 q -= (N_words * n_cards_back); | |
650 assert(q >= _sp->bottom(), "Went below bottom!"); | |
651 index -= n_cards_back; | |
652 offset = _array->offset_array(index); | |
653 } | |
654 while (offset == N_words) { | |
655 assert(q >= _sp->bottom(), "Went below bottom!"); | |
656 q -= N_words; | |
657 index--; | |
658 offset = _array->offset_array(index); | |
659 } | |
660 assert(offset < N_words, "offset too large"); | |
661 q -= offset; | |
662 HeapWord* n = q; | |
663 | |
664 while (n <= addr) { | |
665 debug_only(HeapWord* last = q); // for debugging | |
666 q = n; | |
667 n += _sp->block_size(n); | |
668 } | |
669 assert(q <= addr, "wrong order for current and arg"); | |
670 assert(addr <= n, "wrong order for arg and next"); | |
671 return q; | |
672 } | |
673 | |
674 // | |
675 // _next_offset_threshold | |
676 // | _next_offset_index | |
677 // v v | |
678 // +-------+-------+-------+-------+-------+ | |
679 // | i-1 | i | i+1 | i+2 | i+3 | | |
680 // +-------+-------+-------+-------+-------+ | |
681 // ( ^ ] | |
682 // block-start | |
683 // | |
684 | |
685 void BlockOffsetArrayContigSpace::alloc_block_work(HeapWord* blk_start, | |
686 HeapWord* blk_end) { | |
687 assert(blk_start != NULL && blk_end > blk_start, | |
688 "phantom block"); | |
689 assert(blk_end > _next_offset_threshold, | |
690 "should be past threshold"); | |
691 assert(blk_start <= _next_offset_threshold, | |
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692 "blk_start should be at or before threshold"); |
0 | 693 assert(pointer_delta(_next_offset_threshold, blk_start) <= N_words, |
694 "offset should be <= BlockOffsetSharedArray::N"); | |
695 assert(Universe::heap()->is_in_reserved(blk_start), | |
696 "reference must be into the heap"); | |
697 assert(Universe::heap()->is_in_reserved(blk_end-1), | |
698 "limit must be within the heap"); | |
699 assert(_next_offset_threshold == | |
700 _array->_reserved.start() + _next_offset_index*N_words, | |
701 "index must agree with threshold"); | |
702 | |
703 debug_only(size_t orig_next_offset_index = _next_offset_index;) | |
704 | |
705 // Mark the card that holds the offset into the block. Note | |
706 // that _next_offset_index and _next_offset_threshold are not | |
707 // updated until the end of this method. | |
708 _array->set_offset_array(_next_offset_index, | |
709 _next_offset_threshold, | |
710 blk_start); | |
711 | |
712 // We need to now mark the subsequent cards that this blk spans. | |
713 | |
714 // Index of card on which blk ends. | |
715 size_t end_index = _array->index_for(blk_end - 1); | |
716 | |
717 // Are there more cards left to be updated? | |
718 if (_next_offset_index + 1 <= end_index) { | |
719 HeapWord* rem_st = _array->address_for_index(_next_offset_index + 1); | |
720 // Calculate rem_end this way because end_index | |
721 // may be the last valid index in the covered region. | |
722 HeapWord* rem_end = _array->address_for_index(end_index) + N_words; | |
723 set_remainder_to_point_to_start(rem_st, rem_end); | |
724 } | |
725 | |
726 // _next_offset_index and _next_offset_threshold updated here. | |
727 _next_offset_index = end_index + 1; | |
728 // Calculate _next_offset_threshold this way because end_index | |
729 // may be the last valid index in the covered region. | |
730 _next_offset_threshold = _array->address_for_index(end_index) + | |
731 N_words; | |
732 assert(_next_offset_threshold >= blk_end, "Incorrent offset threshold"); | |
733 | |
734 #ifdef ASSERT | |
735 // The offset can be 0 if the block starts on a boundary. That | |
736 // is checked by an assertion above. | |
737 size_t start_index = _array->index_for(blk_start); | |
738 HeapWord* boundary = _array->address_for_index(start_index); | |
739 assert((_array->offset_array(orig_next_offset_index) == 0 && | |
740 blk_start == boundary) || | |
741 (_array->offset_array(orig_next_offset_index) > 0 && | |
742 _array->offset_array(orig_next_offset_index) <= N_words), | |
743 "offset array should have been set"); | |
744 for (size_t j = orig_next_offset_index + 1; j <= end_index; j++) { | |
745 assert(_array->offset_array(j) > 0 && | |
746 _array->offset_array(j) <= (u_char) (N_words+N_powers-1), | |
747 "offset array should have been set"); | |
748 } | |
749 #endif | |
750 } | |
751 | |
752 HeapWord* BlockOffsetArrayContigSpace::initialize_threshold() { | |
753 assert(!Universe::heap()->is_in_reserved(_array->_offset_array), | |
754 "just checking"); | |
755 _next_offset_index = _array->index_for(_bottom); | |
756 _next_offset_index++; | |
757 _next_offset_threshold = | |
758 _array->address_for_index(_next_offset_index); | |
759 return _next_offset_threshold; | |
760 } | |
761 | |
762 void BlockOffsetArrayContigSpace::zero_bottom_entry() { | |
763 assert(!Universe::heap()->is_in_reserved(_array->_offset_array), | |
764 "just checking"); | |
765 size_t bottom_index = _array->index_for(_bottom); | |
766 _array->set_offset_array(bottom_index, 0); | |
767 } | |
768 | |
769 | |
770 void BlockOffsetArrayContigSpace::serialize(SerializeOopClosure* soc) { | |
771 if (soc->reading()) { | |
772 // Null these values so that the serializer won't object to updating them. | |
773 _next_offset_threshold = NULL; | |
774 _next_offset_index = 0; | |
775 } | |
776 soc->do_ptr(&_next_offset_threshold); | |
777 soc->do_size_t(&_next_offset_index); | |
778 } | |
779 | |
780 size_t BlockOffsetArrayContigSpace::last_active_index() const { | |
781 size_t result = _next_offset_index - 1; | |
782 return result >= 0 ? result : 0; | |
783 } |