Mercurial > hg > graal-compiler
annotate src/share/vm/memory/blockOffsetTable.cpp @ 1722:effb55808a18
Merge
author | johnc |
---|---|
date | Wed, 18 Aug 2010 17:44:33 -0400 |
parents | be3f9c242c9d |
children | f95d63e2154a |
rev | line source |
---|---|
0 | 1 /* |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
2 * Copyright (c) 2000, 2010, 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 * | |
1552
c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
trims
parents:
1489
diff
changeset
|
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
trims
parents:
1489
diff
changeset
|
20 * or visit www.oracle.com if you need additional information or have any |
c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
trims
parents:
1489
diff
changeset
|
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, | |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
106 MemRegion mr, bool init_to_zero_) : |
0 | 107 BlockOffsetTable(mr.start(), mr.end()), |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
108 _array(array) |
0 | 109 { |
110 assert(_bottom <= _end, "arguments out of order"); | |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
111 set_init_to_zero(init_to_zero_); |
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
112 if (!init_to_zero_) { |
0 | 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:: | |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
124 set_remainder_to_point_to_start(HeapWord* start, HeapWord* end, bool reducing) { |
0 | 125 |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
126 check_reducing_assertion(reducing); |
0 | 127 if (start >= end) { |
128 // The start address is equal to the end address (or to | |
129 // the right of the end address) so there are not cards | |
130 // that need to be updated.. | |
131 return; | |
132 } | |
133 | |
134 // Write the backskip value for each region. | |
135 // | |
136 // offset | |
137 // card 2nd 3rd | |
138 // | +- 1st | | | |
139 // v v v v | |
140 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+- | |
141 // |x|0|0|0|0|0|0|0|1|1|1|1|1|1| ... |1|1|1|1|2|2|2|2|2|2| ... | |
142 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+- | |
143 // 11 19 75 | |
144 // 12 | |
145 // | |
146 // offset card is the card that points to the start of an object | |
147 // x - offset value of offset card | |
148 // 1st - start of first logarithmic region | |
149 // 0 corresponds to logarithmic value N_words + 0 and 2**(3 * 0) = 1 | |
150 // 2nd - start of second logarithmic region | |
151 // 1 corresponds to logarithmic value N_words + 1 and 2**(3 * 1) = 8 | |
152 // 3rd - start of third logarithmic region | |
153 // 2 corresponds to logarithmic value N_words + 2 and 2**(3 * 2) = 64 | |
154 // | |
155 // integer below the block offset entry is an example of | |
156 // the index of the entry | |
157 // | |
158 // Given an address, | |
159 // Find the index for the address | |
160 // Find the block offset table entry | |
161 // Convert the entry to a back slide | |
162 // (e.g., with today's, offset = 0x81 => | |
163 // back slip = 2**(3*(0x81 - N_words)) = 2**3) = 8 | |
164 // Move back N (e.g., 8) entries and repeat with the | |
165 // value of the new entry | |
166 // | |
167 size_t start_card = _array->index_for(start); | |
168 size_t end_card = _array->index_for(end-1); | |
169 assert(start ==_array->address_for_index(start_card), "Precondition"); | |
170 assert(end ==_array->address_for_index(end_card)+N_words, "Precondition"); | |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
171 set_remainder_to_point_to_start_incl(start_card, end_card, reducing); // closed interval |
0 | 172 } |
173 | |
174 | |
175 // Unlike the normal convention in this code, the argument here denotes | |
176 // a closed, inclusive interval: [start_card, end_card], cf set_remainder_to_point_to_start() | |
177 // above. | |
178 void | |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
179 BlockOffsetArray::set_remainder_to_point_to_start_incl(size_t start_card, size_t end_card, bool reducing) { |
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
180 |
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
181 check_reducing_assertion(reducing); |
0 | 182 if (start_card > end_card) { |
183 return; | |
184 } | |
185 assert(start_card > _array->index_for(_bottom), "Cannot be first card"); | |
186 assert(_array->offset_array(start_card-1) <= N_words, | |
187 "Offset card has an unexpected value"); | |
188 size_t start_card_for_region = start_card; | |
189 u_char offset = max_jubyte; | |
342 | 190 for (int i = 0; i < N_powers; i++) { |
0 | 191 // -1 so that the the card with the actual offset is counted. Another -1 |
192 // so that the reach ends in this region and not at the start | |
193 // of the next. | |
194 size_t reach = start_card - 1 + (power_to_cards_back(i+1) - 1); | |
195 offset = N_words + i; | |
196 if (reach >= end_card) { | |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
197 _array->set_offset_array(start_card_for_region, end_card, offset, reducing); |
0 | 198 start_card_for_region = reach + 1; |
199 break; | |
200 } | |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
201 _array->set_offset_array(start_card_for_region, reach, offset, reducing); |
0 | 202 start_card_for_region = reach + 1; |
203 } | |
204 assert(start_card_for_region > end_card, "Sanity check"); | |
205 DEBUG_ONLY(check_all_cards(start_card, end_card);) | |
206 } | |
207 | |
208 // The card-interval [start_card, end_card] is a closed interval; this | |
209 // is an expensive check -- use with care and only under protection of | |
210 // suitable flag. | |
211 void BlockOffsetArray::check_all_cards(size_t start_card, size_t end_card) const { | |
212 | |
213 if (end_card < start_card) { | |
214 return; | |
215 } | |
216 guarantee(_array->offset_array(start_card) == N_words, "Wrong value in second card"); | |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
217 u_char last_entry = N_words; |
0 | 218 for (size_t c = start_card + 1; c <= end_card; c++ /* yeah! */) { |
219 u_char entry = _array->offset_array(c); | |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
220 guarantee(entry >= last_entry, "Monotonicity"); |
0 | 221 if (c - start_card > power_to_cards_back(1)) { |
222 guarantee(entry > N_words, "Should be in logarithmic region"); | |
223 } | |
224 size_t backskip = entry_to_cards_back(entry); | |
225 size_t landing_card = c - backskip; | |
226 guarantee(landing_card >= (start_card - 1), "Inv"); | |
227 if (landing_card >= start_card) { | |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
228 guarantee(_array->offset_array(landing_card) <= entry, "Monotonicity"); |
0 | 229 } else { |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
230 guarantee(landing_card == (start_card - 1), "Tautology"); |
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
231 // Note that N_words is the maximum offset value |
0 | 232 guarantee(_array->offset_array(landing_card) <= N_words, "Offset value"); |
233 } | |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
234 last_entry = entry; // remember for monotonicity test |
0 | 235 } |
236 } | |
237 | |
238 | |
239 void | |
240 BlockOffsetArray::alloc_block(HeapWord* blk_start, HeapWord* blk_end) { | |
241 assert(blk_start != NULL && blk_end > blk_start, | |
242 "phantom block"); | |
243 single_block(blk_start, blk_end); | |
244 } | |
245 | |
246 // Action_mark - update the BOT for the block [blk_start, blk_end). | |
247 // Current typical use is for splitting a block. | |
248 // Action_single - udpate the BOT for an allocation. | |
249 // Action_verify - BOT verification. | |
250 void | |
251 BlockOffsetArray::do_block_internal(HeapWord* blk_start, | |
252 HeapWord* blk_end, | |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
253 Action action, bool reducing) { |
0 | 254 assert(Universe::heap()->is_in_reserved(blk_start), |
255 "reference must be into the heap"); | |
256 assert(Universe::heap()->is_in_reserved(blk_end-1), | |
257 "limit must be within the heap"); | |
258 // This is optimized to make the test fast, assuming we only rarely | |
259 // cross boundaries. | |
260 uintptr_t end_ui = (uintptr_t)(blk_end - 1); | |
261 uintptr_t start_ui = (uintptr_t)blk_start; | |
262 // Calculate the last card boundary preceding end of blk | |
263 intptr_t boundary_before_end = (intptr_t)end_ui; | |
264 clear_bits(boundary_before_end, right_n_bits(LogN)); | |
265 if (start_ui <= (uintptr_t)boundary_before_end) { | |
266 // blk starts at or crosses a boundary | |
267 // Calculate index of card on which blk begins | |
268 size_t start_index = _array->index_for(blk_start); | |
269 // Index of card on which blk ends | |
270 size_t end_index = _array->index_for(blk_end - 1); | |
271 // Start address of card on which blk begins | |
272 HeapWord* boundary = _array->address_for_index(start_index); | |
273 assert(boundary <= blk_start, "blk should start at or after boundary"); | |
274 if (blk_start != boundary) { | |
275 // blk starts strictly after boundary | |
276 // adjust card boundary and start_index forward to next card | |
277 boundary += N_words; | |
278 start_index++; | |
279 } | |
280 assert(start_index <= end_index, "monotonicity of index_for()"); | |
281 assert(boundary <= (HeapWord*)boundary_before_end, "tautology"); | |
282 switch (action) { | |
283 case Action_mark: { | |
284 if (init_to_zero()) { | |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
285 _array->set_offset_array(start_index, boundary, blk_start, reducing); |
0 | 286 break; |
287 } // Else fall through to the next case | |
288 } | |
289 case Action_single: { | |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
290 _array->set_offset_array(start_index, boundary, blk_start, reducing); |
0 | 291 // We have finished marking the "offset card". We need to now |
292 // mark the subsequent cards that this blk spans. | |
293 if (start_index < end_index) { | |
294 HeapWord* rem_st = _array->address_for_index(start_index) + N_words; | |
295 HeapWord* rem_end = _array->address_for_index(end_index) + N_words; | |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
296 set_remainder_to_point_to_start(rem_st, rem_end, reducing); |
0 | 297 } |
298 break; | |
299 } | |
300 case Action_check: { | |
301 _array->check_offset_array(start_index, boundary, blk_start); | |
302 // We have finished checking the "offset card". We need to now | |
303 // check the subsequent cards that this blk spans. | |
304 check_all_cards(start_index + 1, end_index); | |
305 break; | |
306 } | |
307 default: | |
308 ShouldNotReachHere(); | |
309 } | |
310 } | |
311 } | |
312 | |
313 // The range [blk_start, blk_end) represents a single contiguous block | |
314 // of storage; modify the block offset table to represent this | |
315 // information; Right-open interval: [blk_start, blk_end) | |
316 // NOTE: this method does _not_ adjust _unallocated_block. | |
317 void | |
318 BlockOffsetArray::single_block(HeapWord* blk_start, | |
319 HeapWord* blk_end) { | |
320 do_block_internal(blk_start, blk_end, Action_single); | |
321 } | |
322 | |
323 void BlockOffsetArray::verify() const { | |
324 // For each entry in the block offset table, verify that | |
325 // the entry correctly finds the start of an object at the | |
326 // first address covered by the block or to the left of that | |
327 // first address. | |
328 | |
329 size_t next_index = 1; | |
330 size_t last_index = last_active_index(); | |
331 | |
332 // Use for debugging. Initialize to NULL to distinguish the | |
333 // first iteration through the while loop. | |
334 HeapWord* last_p = NULL; | |
335 HeapWord* last_start = NULL; | |
336 oop last_o = NULL; | |
337 | |
338 while (next_index <= last_index) { | |
339 // Use an address past the start of the address for | |
340 // the entry. | |
341 HeapWord* p = _array->address_for_index(next_index) + 1; | |
342 if (p >= _end) { | |
343 // That's all of the allocated block table. | |
344 return; | |
345 } | |
346 // block_start() asserts that start <= p. | |
347 HeapWord* start = block_start(p); | |
348 // First check if the start is an allocated block and only | |
349 // then if it is a valid object. | |
350 oop o = oop(start); | |
351 assert(!Universe::is_fully_initialized() || | |
352 _sp->is_free_block(start) || | |
353 o->is_oop_or_null(), "Bad object was found"); | |
354 next_index++; | |
355 last_p = p; | |
356 last_start = start; | |
357 last_o = o; | |
358 } | |
359 } | |
360 | |
361 ////////////////////////////////////////////////////////////////////// | |
362 // BlockOffsetArrayNonContigSpace | |
363 ////////////////////////////////////////////////////////////////////// | |
364 | |
365 // The block [blk_start, blk_end) has been allocated; | |
366 // adjust the block offset table to represent this information; | |
367 // NOTE: Clients of BlockOffsetArrayNonContigSpace: consider using | |
368 // the somewhat more lightweight split_block() or | |
369 // (when init_to_zero()) mark_block() wherever possible. | |
370 // right-open interval: [blk_start, blk_end) | |
371 void | |
372 BlockOffsetArrayNonContigSpace::alloc_block(HeapWord* blk_start, | |
373 HeapWord* blk_end) { | |
374 assert(blk_start != NULL && blk_end > blk_start, | |
375 "phantom block"); | |
376 single_block(blk_start, blk_end); | |
377 allocated(blk_start, blk_end); | |
378 } | |
379 | |
380 // Adjust BOT to show that a previously whole block has been split | |
381 // into two. We verify the BOT for the first part (prefix) and | |
382 // update the BOT for the second part (suffix). | |
383 // blk is the start of the block | |
384 // blk_size is the size of the original block | |
385 // left_blk_size is the size of the first part of the split | |
386 void BlockOffsetArrayNonContigSpace::split_block(HeapWord* blk, | |
387 size_t blk_size, | |
388 size_t left_blk_size) { | |
389 // Verify that the BOT shows [blk, blk + blk_size) to be one block. | |
390 verify_single_block(blk, blk_size); | |
391 // Update the BOT to indicate that [blk + left_blk_size, blk + blk_size) | |
392 // is one single block. | |
393 assert(blk_size > 0, "Should be positive"); | |
394 assert(left_blk_size > 0, "Should be positive"); | |
395 assert(left_blk_size < blk_size, "Not a split"); | |
396 | |
397 // Start addresses of prefix block and suffix block. | |
398 HeapWord* pref_addr = blk; | |
399 HeapWord* suff_addr = blk + left_blk_size; | |
400 HeapWord* end_addr = blk + blk_size; | |
401 | |
402 // Indices for starts of prefix block and suffix block. | |
403 size_t pref_index = _array->index_for(pref_addr); | |
404 if (_array->address_for_index(pref_index) != pref_addr) { | |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
405 // pref_addr does not begin pref_index |
0 | 406 pref_index++; |
407 } | |
408 | |
409 size_t suff_index = _array->index_for(suff_addr); | |
410 if (_array->address_for_index(suff_index) != suff_addr) { | |
411 // suff_addr does not begin suff_index | |
412 suff_index++; | |
413 } | |
414 | |
415 // Definition: A block B, denoted [B_start, B_end) __starts__ | |
416 // a card C, denoted [C_start, C_end), where C_start and C_end | |
417 // are the heap addresses that card C covers, iff | |
418 // B_start <= C_start < B_end. | |
419 // | |
420 // We say that a card C "is started by" a block B, iff | |
421 // B "starts" C. | |
422 // | |
423 // Note that the cardinality of the set of cards {C} | |
424 // started by a block B can be 0, 1, or more. | |
425 // | |
426 // Below, pref_index and suff_index are, respectively, the | |
427 // first (least) card indices that the prefix and suffix of | |
428 // the split start; end_index is one more than the index of | |
429 // the last (greatest) card that blk starts. | |
430 size_t end_index = _array->index_for(end_addr - 1) + 1; | |
431 | |
432 // Calculate the # cards that the prefix and suffix affect. | |
433 size_t num_pref_cards = suff_index - pref_index; | |
434 | |
435 size_t num_suff_cards = end_index - suff_index; | |
436 // Change the cards that need changing | |
437 if (num_suff_cards > 0) { | |
438 HeapWord* boundary = _array->address_for_index(suff_index); | |
439 // Set the offset card for suffix block | |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
440 _array->set_offset_array(suff_index, boundary, suff_addr, true /* reducing */); |
0 | 441 // Change any further cards that need changing in the suffix |
442 if (num_pref_cards > 0) { | |
443 if (num_pref_cards >= num_suff_cards) { | |
444 // Unilaterally fix all of the suffix cards: closed card | |
445 // index interval in args below. | |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
446 set_remainder_to_point_to_start_incl(suff_index + 1, end_index - 1, true /* reducing */); |
0 | 447 } else { |
448 // Unilaterally fix the first (num_pref_cards - 1) following | |
449 // the "offset card" in the suffix block. | |
450 set_remainder_to_point_to_start_incl(suff_index + 1, | |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
451 suff_index + num_pref_cards - 1, true /* reducing */); |
0 | 452 // Fix the appropriate cards in the remainder of the |
453 // suffix block -- these are the last num_pref_cards | |
454 // cards in each power block of the "new" range plumbed | |
455 // from suff_addr. | |
456 bool more = true; | |
457 uint i = 1; | |
458 while (more && (i < N_powers)) { | |
459 size_t back_by = power_to_cards_back(i); | |
460 size_t right_index = suff_index + back_by - 1; | |
461 size_t left_index = right_index - num_pref_cards + 1; | |
462 if (right_index >= end_index - 1) { // last iteration | |
463 right_index = end_index - 1; | |
464 more = false; | |
465 } | |
466 if (back_by > num_pref_cards) { | |
467 // Fill in the remainder of this "power block", if it | |
468 // is non-null. | |
469 if (left_index <= right_index) { | |
470 _array->set_offset_array(left_index, right_index, | |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
471 N_words + i - 1, true /* reducing */); |
0 | 472 } else { |
473 more = false; // we are done | |
474 } | |
475 i++; | |
476 break; | |
477 } | |
478 i++; | |
479 } | |
480 while (more && (i < N_powers)) { | |
481 size_t back_by = power_to_cards_back(i); | |
482 size_t right_index = suff_index + back_by - 1; | |
483 size_t left_index = right_index - num_pref_cards + 1; | |
484 if (right_index >= end_index - 1) { // last iteration | |
485 right_index = end_index - 1; | |
486 if (left_index > right_index) { | |
487 break; | |
488 } | |
489 more = false; | |
490 } | |
491 assert(left_index <= right_index, "Error"); | |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
492 _array->set_offset_array(left_index, right_index, N_words + i - 1, true /* reducing */); |
0 | 493 i++; |
494 } | |
495 } | |
496 } // else no more cards to fix in suffix | |
497 } // else nothing needs to be done | |
498 // Verify that we did the right thing | |
499 verify_single_block(pref_addr, left_blk_size); | |
500 verify_single_block(suff_addr, blk_size - left_blk_size); | |
501 } | |
502 | |
503 | |
504 // Mark the BOT such that if [blk_start, blk_end) straddles a card | |
505 // boundary, the card following the first such boundary is marked | |
506 // with the appropriate offset. | |
507 // NOTE: this method does _not_ adjust _unallocated_block or | |
508 // any cards subsequent to the first one. | |
509 void | |
510 BlockOffsetArrayNonContigSpace::mark_block(HeapWord* blk_start, | |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
511 HeapWord* blk_end, bool reducing) { |
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
512 do_block_internal(blk_start, blk_end, Action_mark, reducing); |
0 | 513 } |
514 | |
515 HeapWord* BlockOffsetArrayNonContigSpace::block_start_unsafe( | |
516 const void* addr) const { | |
517 assert(_array->offset_array(0) == 0, "objects can't cross covered areas"); | |
518 assert(_bottom <= addr && addr < _end, | |
519 "addr must be covered by this Array"); | |
520 // Must read this exactly once because it can be modified by parallel | |
521 // allocation. | |
522 HeapWord* ub = _unallocated_block; | |
523 if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) { | |
524 assert(ub < _end, "tautology (see above)"); | |
525 return ub; | |
526 } | |
527 | |
528 // Otherwise, find the block start using the table. | |
529 size_t index = _array->index_for(addr); | |
530 HeapWord* q = _array->address_for_index(index); | |
531 | |
532 uint offset = _array->offset_array(index); // Extend u_char to uint. | |
533 while (offset >= N_words) { | |
534 // The excess of the offset from N_words indicates a power of Base | |
535 // to go back by. | |
536 size_t n_cards_back = entry_to_cards_back(offset); | |
537 q -= (N_words * n_cards_back); | |
538 assert(q >= _sp->bottom(), "Went below bottom!"); | |
539 index -= n_cards_back; | |
540 offset = _array->offset_array(index); | |
541 } | |
542 assert(offset < N_words, "offset too large"); | |
543 index--; | |
544 q -= offset; | |
545 HeapWord* n = q; | |
546 | |
547 while (n <= addr) { | |
548 debug_only(HeapWord* last = q); // for debugging | |
549 q = n; | |
550 n += _sp->block_size(n); | |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
551 assert(n > q, err_msg("Looping at: " INTPTR_FORMAT, n)); |
0 | 552 } |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
553 assert(q <= addr, err_msg("wrong order for current (" INTPTR_FORMAT ") <= arg (" INTPTR_FORMAT ")", q, addr)); |
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
554 assert(addr <= n, err_msg("wrong order for arg (" INTPTR_FORMAT ") <= next (" INTPTR_FORMAT ")", addr, n)); |
0 | 555 return q; |
556 } | |
557 | |
558 HeapWord* BlockOffsetArrayNonContigSpace::block_start_careful( | |
559 const void* addr) const { | |
560 assert(_array->offset_array(0) == 0, "objects can't cross covered areas"); | |
561 | |
562 assert(_bottom <= addr && addr < _end, | |
563 "addr must be covered by this Array"); | |
564 // Must read this exactly once because it can be modified by parallel | |
565 // allocation. | |
566 HeapWord* ub = _unallocated_block; | |
567 if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) { | |
568 assert(ub < _end, "tautology (see above)"); | |
569 return ub; | |
570 } | |
571 | |
572 // Otherwise, find the block start using the table, but taking | |
573 // care (cf block_start_unsafe() above) not to parse any objects/blocks | |
574 // on the cards themsleves. | |
575 size_t index = _array->index_for(addr); | |
576 assert(_array->address_for_index(index) == addr, | |
577 "arg should be start of card"); | |
578 | |
579 HeapWord* q = (HeapWord*)addr; | |
580 uint offset; | |
581 do { | |
582 offset = _array->offset_array(index); | |
583 if (offset < N_words) { | |
584 q -= offset; | |
585 } else { | |
586 size_t n_cards_back = entry_to_cards_back(offset); | |
587 q -= (n_cards_back * N_words); | |
588 index -= n_cards_back; | |
589 } | |
590 } while (offset >= N_words); | |
591 assert(q <= addr, "block start should be to left of arg"); | |
592 return q; | |
593 } | |
594 | |
595 #ifndef PRODUCT | |
596 // Verification & debugging - ensure that the offset table reflects the fact | |
597 // that the block [blk_start, blk_end) or [blk, blk + size) is a | |
598 // single block of storage. NOTE: can't const this because of | |
599 // call to non-const do_block_internal() below. | |
600 void BlockOffsetArrayNonContigSpace::verify_single_block( | |
601 HeapWord* blk_start, HeapWord* blk_end) { | |
602 if (VerifyBlockOffsetArray) { | |
603 do_block_internal(blk_start, blk_end, Action_check); | |
604 } | |
605 } | |
606 | |
607 void BlockOffsetArrayNonContigSpace::verify_single_block( | |
608 HeapWord* blk, size_t size) { | |
609 verify_single_block(blk, blk + size); | |
610 } | |
611 | |
612 // Verify that the given block is before _unallocated_block | |
613 void BlockOffsetArrayNonContigSpace::verify_not_unallocated( | |
614 HeapWord* blk_start, HeapWord* blk_end) const { | |
615 if (BlockOffsetArrayUseUnallocatedBlock) { | |
616 assert(blk_start < blk_end, "Block inconsistency?"); | |
617 assert(blk_end <= _unallocated_block, "_unallocated_block problem"); | |
618 } | |
619 } | |
620 | |
621 void BlockOffsetArrayNonContigSpace::verify_not_unallocated( | |
622 HeapWord* blk, size_t size) const { | |
623 verify_not_unallocated(blk, blk + size); | |
624 } | |
625 #endif // PRODUCT | |
626 | |
627 size_t BlockOffsetArrayNonContigSpace::last_active_index() const { | |
628 if (_unallocated_block == _bottom) { | |
629 return 0; | |
630 } else { | |
631 return _array->index_for(_unallocated_block - 1); | |
632 } | |
633 } | |
634 | |
635 ////////////////////////////////////////////////////////////////////// | |
636 // BlockOffsetArrayContigSpace | |
637 ////////////////////////////////////////////////////////////////////// | |
638 | |
639 HeapWord* BlockOffsetArrayContigSpace::block_start_unsafe(const void* addr) const { | |
640 assert(_array->offset_array(0) == 0, "objects can't cross covered areas"); | |
641 | |
642 // Otherwise, find the block start using the table. | |
643 assert(_bottom <= addr && addr < _end, | |
644 "addr must be covered by this Array"); | |
645 size_t index = _array->index_for(addr); | |
646 // We must make sure that the offset table entry we use is valid. If | |
647 // "addr" is past the end, start at the last known one and go forward. | |
648 index = MIN2(index, _next_offset_index-1); | |
649 HeapWord* q = _array->address_for_index(index); | |
650 | |
651 uint offset = _array->offset_array(index); // Extend u_char to uint. | |
652 while (offset > N_words) { | |
653 // The excess of the offset from N_words indicates a power of Base | |
654 // to go back by. | |
655 size_t n_cards_back = entry_to_cards_back(offset); | |
656 q -= (N_words * n_cards_back); | |
657 assert(q >= _sp->bottom(), "Went below bottom!"); | |
658 index -= n_cards_back; | |
659 offset = _array->offset_array(index); | |
660 } | |
661 while (offset == N_words) { | |
662 assert(q >= _sp->bottom(), "Went below bottom!"); | |
663 q -= N_words; | |
664 index--; | |
665 offset = _array->offset_array(index); | |
666 } | |
667 assert(offset < N_words, "offset too large"); | |
668 q -= offset; | |
669 HeapWord* n = q; | |
670 | |
671 while (n <= addr) { | |
672 debug_only(HeapWord* last = q); // for debugging | |
673 q = n; | |
674 n += _sp->block_size(n); | |
675 } | |
676 assert(q <= addr, "wrong order for current and arg"); | |
677 assert(addr <= n, "wrong order for arg and next"); | |
678 return q; | |
679 } | |
680 | |
681 // | |
682 // _next_offset_threshold | |
683 // | _next_offset_index | |
684 // v v | |
685 // +-------+-------+-------+-------+-------+ | |
686 // | i-1 | i | i+1 | i+2 | i+3 | | |
687 // +-------+-------+-------+-------+-------+ | |
688 // ( ^ ] | |
689 // block-start | |
690 // | |
691 | |
692 void BlockOffsetArrayContigSpace::alloc_block_work(HeapWord* blk_start, | |
693 HeapWord* blk_end) { | |
694 assert(blk_start != NULL && blk_end > blk_start, | |
695 "phantom block"); | |
696 assert(blk_end > _next_offset_threshold, | |
697 "should be past threshold"); | |
698 assert(blk_start <= _next_offset_threshold, | |
1489
cff162798819
6888953: some calls to function-like macros are missing semicolons
jcoomes
parents:
342
diff
changeset
|
699 "blk_start should be at or before threshold"); |
0 | 700 assert(pointer_delta(_next_offset_threshold, blk_start) <= N_words, |
701 "offset should be <= BlockOffsetSharedArray::N"); | |
702 assert(Universe::heap()->is_in_reserved(blk_start), | |
703 "reference must be into the heap"); | |
704 assert(Universe::heap()->is_in_reserved(blk_end-1), | |
705 "limit must be within the heap"); | |
706 assert(_next_offset_threshold == | |
707 _array->_reserved.start() + _next_offset_index*N_words, | |
708 "index must agree with threshold"); | |
709 | |
710 debug_only(size_t orig_next_offset_index = _next_offset_index;) | |
711 | |
712 // Mark the card that holds the offset into the block. Note | |
713 // that _next_offset_index and _next_offset_threshold are not | |
714 // updated until the end of this method. | |
715 _array->set_offset_array(_next_offset_index, | |
716 _next_offset_threshold, | |
717 blk_start); | |
718 | |
719 // We need to now mark the subsequent cards that this blk spans. | |
720 | |
721 // Index of card on which blk ends. | |
722 size_t end_index = _array->index_for(blk_end - 1); | |
723 | |
724 // Are there more cards left to be updated? | |
725 if (_next_offset_index + 1 <= end_index) { | |
726 HeapWord* rem_st = _array->address_for_index(_next_offset_index + 1); | |
727 // Calculate rem_end this way because end_index | |
728 // may be the last valid index in the covered region. | |
729 HeapWord* rem_end = _array->address_for_index(end_index) + N_words; | |
730 set_remainder_to_point_to_start(rem_st, rem_end); | |
731 } | |
732 | |
733 // _next_offset_index and _next_offset_threshold updated here. | |
734 _next_offset_index = end_index + 1; | |
735 // Calculate _next_offset_threshold this way because end_index | |
736 // may be the last valid index in the covered region. | |
1716
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
737 _next_offset_threshold = _array->address_for_index(end_index) + N_words; |
be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
ysr
parents:
1552
diff
changeset
|
738 assert(_next_offset_threshold >= blk_end, "Incorrect offset threshold"); |
0 | 739 |
740 #ifdef ASSERT | |
741 // The offset can be 0 if the block starts on a boundary. That | |
742 // is checked by an assertion above. | |
743 size_t start_index = _array->index_for(blk_start); | |
744 HeapWord* boundary = _array->address_for_index(start_index); | |
745 assert((_array->offset_array(orig_next_offset_index) == 0 && | |
746 blk_start == boundary) || | |
747 (_array->offset_array(orig_next_offset_index) > 0 && | |
748 _array->offset_array(orig_next_offset_index) <= N_words), | |
749 "offset array should have been set"); | |
750 for (size_t j = orig_next_offset_index + 1; j <= end_index; j++) { | |
751 assert(_array->offset_array(j) > 0 && | |
752 _array->offset_array(j) <= (u_char) (N_words+N_powers-1), | |
753 "offset array should have been set"); | |
754 } | |
755 #endif | |
756 } | |
757 | |
758 HeapWord* BlockOffsetArrayContigSpace::initialize_threshold() { | |
759 assert(!Universe::heap()->is_in_reserved(_array->_offset_array), | |
760 "just checking"); | |
761 _next_offset_index = _array->index_for(_bottom); | |
762 _next_offset_index++; | |
763 _next_offset_threshold = | |
764 _array->address_for_index(_next_offset_index); | |
765 return _next_offset_threshold; | |
766 } | |
767 | |
768 void BlockOffsetArrayContigSpace::zero_bottom_entry() { | |
769 assert(!Universe::heap()->is_in_reserved(_array->_offset_array), | |
770 "just checking"); | |
771 size_t bottom_index = _array->index_for(_bottom); | |
772 _array->set_offset_array(bottom_index, 0); | |
773 } | |
774 | |
775 | |
776 void BlockOffsetArrayContigSpace::serialize(SerializeOopClosure* soc) { | |
777 if (soc->reading()) { | |
778 // Null these values so that the serializer won't object to updating them. | |
779 _next_offset_threshold = NULL; | |
780 _next_offset_index = 0; | |
781 } | |
782 soc->do_ptr(&_next_offset_threshold); | |
783 soc->do_size_t(&_next_offset_index); | |
784 } | |
785 | |
786 size_t BlockOffsetArrayContigSpace::last_active_index() const { | |
787 size_t result = _next_offset_index - 1; | |
788 return result >= 0 ? result : 0; | |
789 } |