Mercurial > hg > graal-compiler
annotate src/share/vm/gc_implementation/parNew/parGCAllocBuffer.cpp @ 353:9bb2c10ac07b
6723570: G1: assertion failure: p == current_top or oop(p)->is_oop(),"p is not a block start" (revisited!)
Summary: Fixed the incorrect assigment to G1OffsetTableContigSpace::_gc_time_stamp. Also added a little more paranoia to operations on a global timestamp.
Reviewed-by: tonyp
author | iveresov |
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date | Thu, 10 Jul 2008 09:29:54 -0700 |
parents | ba764ed4b6f2 |
children | d1605aabd0a1 |
rev | line source |
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0 | 1 /* |
2 * Copyright 2001-2006 Sun Microsystems, Inc. All Rights Reserved. | |
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |
4 * | |
5 * This code is free software; you can redistribute it and/or modify it | |
6 * under the terms of the GNU General Public License version 2 only, as | |
7 * published by the Free Software Foundation. | |
8 * | |
9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
12 * version 2 for more details (a copy is included in the LICENSE file that | |
13 * accompanied this code). | |
14 * | |
15 * You should have received a copy of the GNU General Public License version | |
16 * 2 along with this work; if not, write to the Free Software Foundation, | |
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
18 * | |
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
21 * have any questions. | |
22 * | |
23 */ | |
24 | |
25 # include "incls/_precompiled.incl" | |
26 # include "incls/_parGCAllocBuffer.cpp.incl" | |
27 | |
28 ParGCAllocBuffer::ParGCAllocBuffer(size_t desired_plab_sz_) : | |
29 _word_sz(desired_plab_sz_), _bottom(NULL), _top(NULL), | |
30 _end(NULL), _hard_end(NULL), | |
31 _retained(false), _retained_filler(), | |
32 _allocated(0), _wasted(0) | |
33 { | |
34 assert (min_size() > AlignmentReserve, "Inconsistency!"); | |
113
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35 // arrayOopDesc::header_size depends on command line initialization. |
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36 FillerHeaderSize = align_object_size(arrayOopDesc::header_size(T_INT)); |
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37 AlignmentReserve = oopDesc::header_size() > MinObjAlignment ? FillerHeaderSize : 0; |
0 | 38 } |
39 | |
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40 size_t ParGCAllocBuffer::FillerHeaderSize; |
0 | 41 |
42 // If the minimum object size is greater than MinObjAlignment, we can | |
43 // end up with a shard at the end of the buffer that's smaller than | |
44 // the smallest object. We can't allow that because the buffer must | |
45 // look like it's full of objects when we retire it, so we make | |
46 // sure we have enough space for a filler int array object. | |
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47 size_t ParGCAllocBuffer::AlignmentReserve; |
0 | 48 |
49 void ParGCAllocBuffer::retire(bool end_of_gc, bool retain) { | |
50 assert(!retain || end_of_gc, "Can only retain at GC end."); | |
51 if (_retained) { | |
52 // If the buffer had been retained shorten the previous filler object. | |
53 assert(_retained_filler.end() <= _top, "INVARIANT"); | |
54 SharedHeap::fill_region_with_object(_retained_filler); | |
55 // Wasted space book-keeping, otherwise (normally) done in invalidate() | |
56 _wasted += _retained_filler.word_size(); | |
57 _retained = false; | |
58 } | |
59 assert(!end_of_gc || !_retained, "At this point, end_of_gc ==> !_retained."); | |
60 if (_top < _hard_end) { | |
61 SharedHeap::fill_region_with_object(MemRegion(_top, _hard_end)); | |
62 if (!retain) { | |
63 invalidate(); | |
64 } else { | |
65 // Is there wasted space we'd like to retain for the next GC? | |
66 if (pointer_delta(_end, _top) > FillerHeaderSize) { | |
67 _retained = true; | |
68 _retained_filler = MemRegion(_top, FillerHeaderSize); | |
69 _top = _top + FillerHeaderSize; | |
70 } else { | |
71 invalidate(); | |
72 } | |
73 } | |
74 } | |
75 } | |
76 | |
77 void ParGCAllocBuffer::flush_stats(PLABStats* stats) { | |
78 assert(ResizePLAB, "Wasted work"); | |
79 stats->add_allocated(_allocated); | |
80 stats->add_wasted(_wasted); | |
81 stats->add_unused(pointer_delta(_end, _top)); | |
82 } | |
83 | |
84 // Compute desired plab size and latch result for later | |
85 // use. This should be called once at the end of parallel | |
86 // scavenge; it clears the sensor accumulators. | |
87 void PLABStats::adjust_desired_plab_sz() { | |
88 assert(ResizePLAB, "Not set"); | |
89 if (_allocated == 0) { | |
90 assert(_unused == 0, "Inconsistency in PLAB stats"); | |
91 _allocated = 1; | |
92 } | |
93 double wasted_frac = (double)_unused/(double)_allocated; | |
94 size_t target_refills = (size_t)((wasted_frac*TargetSurvivorRatio)/ | |
95 TargetPLABWastePct); | |
96 if (target_refills == 0) { | |
97 target_refills = 1; | |
98 } | |
99 _used = _allocated - _wasted - _unused; | |
100 size_t plab_sz = _used/(target_refills*ParallelGCThreads); | |
101 if (PrintPLAB) gclog_or_tty->print(" (plab_sz = %d ", plab_sz); | |
102 // Take historical weighted average | |
103 _filter.sample(plab_sz); | |
104 // Clip from above and below, and align to object boundary | |
105 plab_sz = MAX2(min_size(), (size_t)_filter.average()); | |
106 plab_sz = MIN2(max_size(), plab_sz); | |
107 plab_sz = align_object_size(plab_sz); | |
108 // Latch the result | |
109 if (PrintPLAB) gclog_or_tty->print(" desired_plab_sz = %d) ", plab_sz); | |
110 if (ResizePLAB) { | |
111 _desired_plab_sz = plab_sz; | |
112 } | |
113 // Now clear the accumulators for next round: | |
114 // note this needs to be fixed in the case where we | |
115 // are retaining across scavenges. FIX ME !!! XXX | |
116 _allocated = 0; | |
117 _wasted = 0; | |
118 _unused = 0; | |
119 } | |
120 | |
121 #ifndef PRODUCT | |
122 void ParGCAllocBuffer::print() { | |
123 gclog_or_tty->print("parGCAllocBuffer: _bottom: %p _top: %p _end: %p _hard_end: %p" | |
124 "_retained: %c _retained_filler: [%p,%p)\n", | |
125 _bottom, _top, _end, _hard_end, | |
126 "FT"[_retained], _retained_filler.start(), _retained_filler.end()); | |
127 } | |
128 #endif // !PRODUCT | |
129 | |
130 const size_t ParGCAllocBufferWithBOT::ChunkSizeInWords = | |
131 MIN2(CardTableModRefBS::par_chunk_heapword_alignment(), | |
132 ((size_t)Generation::GenGrain)/HeapWordSize); | |
133 const size_t ParGCAllocBufferWithBOT::ChunkSizeInBytes = | |
134 MIN2(CardTableModRefBS::par_chunk_heapword_alignment() * HeapWordSize, | |
135 (size_t)Generation::GenGrain); | |
136 | |
137 ParGCAllocBufferWithBOT::ParGCAllocBufferWithBOT(size_t word_sz, | |
138 BlockOffsetSharedArray* bsa) : | |
139 ParGCAllocBuffer(word_sz), | |
140 _bsa(bsa), | |
141 _bt(bsa, MemRegion(_bottom, _hard_end)), | |
142 _true_end(_hard_end) | |
143 {} | |
144 | |
145 // The buffer comes with its own BOT, with a shared (obviously) underlying | |
146 // BlockOffsetSharedArray. We manipulate this BOT in the normal way | |
147 // as we would for any contiguous space. However, on accasion we | |
148 // need to do some buffer surgery at the extremities before we | |
149 // start using the body of the buffer for allocations. Such surgery | |
150 // (as explained elsewhere) is to prevent allocation on a card that | |
151 // is in the process of being walked concurrently by another GC thread. | |
152 // When such surgery happens at a point that is far removed (to the | |
153 // right of the current allocation point, top), we use the "contig" | |
154 // parameter below to directly manipulate the shared array without | |
155 // modifying the _next_threshold state in the BOT. | |
156 void ParGCAllocBufferWithBOT::fill_region_with_block(MemRegion mr, | |
157 bool contig) { | |
158 SharedHeap::fill_region_with_object(mr); | |
159 if (contig) { | |
160 _bt.alloc_block(mr.start(), mr.end()); | |
161 } else { | |
162 _bt.BlockOffsetArray::alloc_block(mr.start(), mr.end()); | |
163 } | |
164 } | |
165 | |
166 HeapWord* ParGCAllocBufferWithBOT::allocate_slow(size_t word_sz) { | |
167 HeapWord* res = NULL; | |
168 if (_true_end > _hard_end) { | |
169 assert((HeapWord*)align_size_down(intptr_t(_hard_end), | |
170 ChunkSizeInBytes) == _hard_end, | |
171 "or else _true_end should be equal to _hard_end"); | |
172 assert(_retained, "or else _true_end should be equal to _hard_end"); | |
173 assert(_retained_filler.end() <= _top, "INVARIANT"); | |
174 SharedHeap::fill_region_with_object(_retained_filler); | |
175 if (_top < _hard_end) { | |
176 fill_region_with_block(MemRegion(_top, _hard_end), true); | |
177 } | |
178 HeapWord* next_hard_end = MIN2(_true_end, _hard_end + ChunkSizeInWords); | |
179 _retained_filler = MemRegion(_hard_end, FillerHeaderSize); | |
180 _bt.alloc_block(_retained_filler.start(), _retained_filler.word_size()); | |
181 _top = _retained_filler.end(); | |
182 _hard_end = next_hard_end; | |
183 _end = _hard_end - AlignmentReserve; | |
184 res = ParGCAllocBuffer::allocate(word_sz); | |
185 if (res != NULL) { | |
186 _bt.alloc_block(res, word_sz); | |
187 } | |
188 } | |
189 return res; | |
190 } | |
191 | |
192 void | |
193 ParGCAllocBufferWithBOT::undo_allocation(HeapWord* obj, size_t word_sz) { | |
194 ParGCAllocBuffer::undo_allocation(obj, word_sz); | |
195 // This may back us up beyond the previous threshold, so reset. | |
196 _bt.set_region(MemRegion(_top, _hard_end)); | |
197 _bt.initialize_threshold(); | |
198 } | |
199 | |
200 void ParGCAllocBufferWithBOT::retire(bool end_of_gc, bool retain) { | |
201 assert(!retain || end_of_gc, "Can only retain at GC end."); | |
202 if (_retained) { | |
203 // We're about to make the retained_filler into a block. | |
204 _bt.BlockOffsetArray::alloc_block(_retained_filler.start(), | |
205 _retained_filler.end()); | |
206 } | |
207 // Reset _hard_end to _true_end (and update _end) | |
208 if (retain && _hard_end != NULL) { | |
209 assert(_hard_end <= _true_end, "Invariant."); | |
210 _hard_end = _true_end; | |
211 _end = MAX2(_top, _hard_end - AlignmentReserve); | |
212 assert(_end <= _hard_end, "Invariant."); | |
213 } | |
214 _true_end = _hard_end; | |
215 HeapWord* pre_top = _top; | |
216 | |
217 ParGCAllocBuffer::retire(end_of_gc, retain); | |
218 // Now any old _retained_filler is cut back to size, the free part is | |
219 // filled with a filler object, and top is past the header of that | |
220 // object. | |
221 | |
222 if (retain && _top < _end) { | |
223 assert(end_of_gc && retain, "Or else retain should be false."); | |
224 // If the lab does not start on a card boundary, we don't want to | |
225 // allocate onto that card, since that might lead to concurrent | |
226 // allocation and card scanning, which we don't support. So we fill | |
227 // the first card with a garbage object. | |
228 size_t first_card_index = _bsa->index_for(pre_top); | |
229 HeapWord* first_card_start = _bsa->address_for_index(first_card_index); | |
230 if (first_card_start < pre_top) { | |
231 HeapWord* second_card_start = | |
232 _bsa->address_for_index(first_card_index + 1); | |
233 | |
234 // Ensure enough room to fill with the smallest block | |
235 second_card_start = MAX2(second_card_start, pre_top + AlignmentReserve); | |
236 | |
237 // If the end is already in the first card, don't go beyond it! | |
238 // Or if the remainder is too small for a filler object, gobble it up. | |
239 if (_hard_end < second_card_start || | |
240 pointer_delta(_hard_end, second_card_start) < AlignmentReserve) { | |
241 second_card_start = _hard_end; | |
242 } | |
243 if (pre_top < second_card_start) { | |
244 MemRegion first_card_suffix(pre_top, second_card_start); | |
245 fill_region_with_block(first_card_suffix, true); | |
246 } | |
247 pre_top = second_card_start; | |
248 _top = pre_top; | |
249 _end = MAX2(_top, _hard_end - AlignmentReserve); | |
250 } | |
251 | |
252 // If the lab does not end on a card boundary, we don't want to | |
253 // allocate onto that card, since that might lead to concurrent | |
254 // allocation and card scanning, which we don't support. So we fill | |
255 // the last card with a garbage object. | |
256 size_t last_card_index = _bsa->index_for(_hard_end); | |
257 HeapWord* last_card_start = _bsa->address_for_index(last_card_index); | |
258 if (last_card_start < _hard_end) { | |
259 | |
260 // Ensure enough room to fill with the smallest block | |
261 last_card_start = MIN2(last_card_start, _hard_end - AlignmentReserve); | |
262 | |
263 // If the top is already in the last card, don't go back beyond it! | |
264 // Or if the remainder is too small for a filler object, gobble it up. | |
265 if (_top > last_card_start || | |
266 pointer_delta(last_card_start, _top) < AlignmentReserve) { | |
267 last_card_start = _top; | |
268 } | |
269 if (last_card_start < _hard_end) { | |
270 MemRegion last_card_prefix(last_card_start, _hard_end); | |
271 fill_region_with_block(last_card_prefix, false); | |
272 } | |
273 _hard_end = last_card_start; | |
274 _end = MAX2(_top, _hard_end - AlignmentReserve); | |
275 _true_end = _hard_end; | |
276 assert(_end <= _hard_end, "Invariant."); | |
277 } | |
278 | |
279 // At this point: | |
280 // 1) we had a filler object from the original top to hard_end. | |
281 // 2) We've filled in any partial cards at the front and back. | |
282 if (pre_top < _hard_end) { | |
283 // Now we can reset the _bt to do allocation in the given area. | |
284 MemRegion new_filler(pre_top, _hard_end); | |
285 fill_region_with_block(new_filler, false); | |
286 _top = pre_top + ParGCAllocBuffer::FillerHeaderSize; | |
287 // If there's no space left, don't retain. | |
288 if (_top >= _end) { | |
289 _retained = false; | |
290 invalidate(); | |
291 return; | |
292 } | |
293 _retained_filler = MemRegion(pre_top, _top); | |
294 _bt.set_region(MemRegion(_top, _hard_end)); | |
295 _bt.initialize_threshold(); | |
296 assert(_bt.threshold() > _top, "initialize_threshold failed!"); | |
297 | |
298 // There may be other reasons for queries into the middle of the | |
299 // filler object. When such queries are done in parallel with | |
300 // allocation, bad things can happen, if the query involves object | |
301 // iteration. So we ensure that such queries do not involve object | |
302 // iteration, by putting another filler object on the boundaries of | |
303 // such queries. One such is the object spanning a parallel card | |
304 // chunk boundary. | |
305 | |
306 // "chunk_boundary" is the address of the first chunk boundary less | |
307 // than "hard_end". | |
308 HeapWord* chunk_boundary = | |
309 (HeapWord*)align_size_down(intptr_t(_hard_end-1), ChunkSizeInBytes); | |
310 assert(chunk_boundary < _hard_end, "Or else above did not work."); | |
311 assert(pointer_delta(_true_end, chunk_boundary) >= AlignmentReserve, | |
312 "Consequence of last card handling above."); | |
313 | |
314 if (_top <= chunk_boundary) { | |
315 assert(_true_end == _hard_end, "Invariant."); | |
316 while (_top <= chunk_boundary) { | |
317 assert(pointer_delta(_hard_end, chunk_boundary) >= AlignmentReserve, | |
318 "Consequence of last card handling above."); | |
319 MemRegion chunk_portion(chunk_boundary, _hard_end); | |
320 _bt.BlockOffsetArray::alloc_block(chunk_portion.start(), | |
321 chunk_portion.end()); | |
322 SharedHeap::fill_region_with_object(chunk_portion); | |
323 _hard_end = chunk_portion.start(); | |
324 chunk_boundary -= ChunkSizeInWords; | |
325 } | |
326 _end = _hard_end - AlignmentReserve; | |
327 assert(_top <= _end, "Invariant."); | |
328 // Now reset the initial filler chunk so it doesn't overlap with | |
329 // the one(s) inserted above. | |
330 MemRegion new_filler(pre_top, _hard_end); | |
331 fill_region_with_block(new_filler, false); | |
332 } | |
333 } else { | |
334 _retained = false; | |
335 invalidate(); | |
336 } | |
337 } else { | |
338 assert(!end_of_gc || | |
339 (!_retained && _true_end == _hard_end), "Checking."); | |
340 } | |
341 assert(_end <= _hard_end, "Invariant."); | |
342 assert(_top < _end || _top == _hard_end, "Invariant"); | |
343 } |