Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/parNew/parGCAllocBuffer.cpp @ 4155:394404b2d9bd
Removed strict requirement for GRAAL environment variable. It only needs to be set now if the graal directory is not in the directory hierarchy of GraalVM JDK.
| author | Doug Simon <doug.simon@oracle.com> |
|---|---|
| date | Wed, 21 Dec 2011 11:25:27 +0100 |
| parents | f95d63e2154a |
| children |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 1972 | 2 * Copyright (c) 2001, 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 * | |
|
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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_implementation/parNew/parGCAllocBuffer.hpp" | |
| 27 #include "memory/sharedHeap.hpp" | |
| 28 #include "oops/arrayOop.hpp" | |
| 29 #include "oops/oop.inline.hpp" | |
| 0 | 30 |
| 31 ParGCAllocBuffer::ParGCAllocBuffer(size_t desired_plab_sz_) : | |
| 32 _word_sz(desired_plab_sz_), _bottom(NULL), _top(NULL), | |
| 33 _end(NULL), _hard_end(NULL), | |
| 34 _retained(false), _retained_filler(), | |
| 35 _allocated(0), _wasted(0) | |
| 36 { | |
| 37 assert (min_size() > AlignmentReserve, "Inconsistency!"); | |
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38 // arrayOopDesc::header_size depends on command line initialization. |
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39 FillerHeaderSize = align_object_size(arrayOopDesc::header_size(T_INT)); |
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40 AlignmentReserve = oopDesc::header_size() > MinObjAlignment ? FillerHeaderSize : 0; |
| 0 | 41 } |
| 42 | |
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43 size_t ParGCAllocBuffer::FillerHeaderSize; |
| 0 | 44 |
| 45 // If the minimum object size is greater than MinObjAlignment, we can | |
| 46 // end up with a shard at the end of the buffer that's smaller than | |
| 47 // the smallest object. We can't allow that because the buffer must | |
| 48 // look like it's full of objects when we retire it, so we make | |
| 49 // sure we have enough space for a filler int array object. | |
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50 size_t ParGCAllocBuffer::AlignmentReserve; |
| 0 | 51 |
| 52 void ParGCAllocBuffer::retire(bool end_of_gc, bool retain) { | |
| 53 assert(!retain || end_of_gc, "Can only retain at GC end."); | |
| 54 if (_retained) { | |
| 55 // If the buffer had been retained shorten the previous filler object. | |
| 56 assert(_retained_filler.end() <= _top, "INVARIANT"); | |
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57 CollectedHeap::fill_with_object(_retained_filler); |
| 0 | 58 // Wasted space book-keeping, otherwise (normally) done in invalidate() |
| 59 _wasted += _retained_filler.word_size(); | |
| 60 _retained = false; | |
| 61 } | |
| 62 assert(!end_of_gc || !_retained, "At this point, end_of_gc ==> !_retained."); | |
| 63 if (_top < _hard_end) { | |
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64 CollectedHeap::fill_with_object(_top, _hard_end); |
| 0 | 65 if (!retain) { |
| 66 invalidate(); | |
| 67 } else { | |
| 68 // Is there wasted space we'd like to retain for the next GC? | |
| 69 if (pointer_delta(_end, _top) > FillerHeaderSize) { | |
| 70 _retained = true; | |
| 71 _retained_filler = MemRegion(_top, FillerHeaderSize); | |
| 72 _top = _top + FillerHeaderSize; | |
| 73 } else { | |
| 74 invalidate(); | |
| 75 } | |
| 76 } | |
| 77 } | |
| 78 } | |
| 79 | |
| 80 void ParGCAllocBuffer::flush_stats(PLABStats* stats) { | |
| 81 assert(ResizePLAB, "Wasted work"); | |
| 82 stats->add_allocated(_allocated); | |
| 83 stats->add_wasted(_wasted); | |
| 84 stats->add_unused(pointer_delta(_end, _top)); | |
| 85 } | |
| 86 | |
| 87 // Compute desired plab size and latch result for later | |
| 88 // use. This should be called once at the end of parallel | |
| 89 // scavenge; it clears the sensor accumulators. | |
| 90 void PLABStats::adjust_desired_plab_sz() { | |
| 91 assert(ResizePLAB, "Not set"); | |
| 92 if (_allocated == 0) { | |
| 93 assert(_unused == 0, "Inconsistency in PLAB stats"); | |
| 94 _allocated = 1; | |
| 95 } | |
| 96 double wasted_frac = (double)_unused/(double)_allocated; | |
| 97 size_t target_refills = (size_t)((wasted_frac*TargetSurvivorRatio)/ | |
| 98 TargetPLABWastePct); | |
| 99 if (target_refills == 0) { | |
| 100 target_refills = 1; | |
| 101 } | |
| 102 _used = _allocated - _wasted - _unused; | |
| 103 size_t plab_sz = _used/(target_refills*ParallelGCThreads); | |
| 104 if (PrintPLAB) gclog_or_tty->print(" (plab_sz = %d ", plab_sz); | |
| 105 // Take historical weighted average | |
| 106 _filter.sample(plab_sz); | |
| 107 // Clip from above and below, and align to object boundary | |
| 108 plab_sz = MAX2(min_size(), (size_t)_filter.average()); | |
| 109 plab_sz = MIN2(max_size(), plab_sz); | |
| 110 plab_sz = align_object_size(plab_sz); | |
| 111 // Latch the result | |
| 112 if (PrintPLAB) gclog_or_tty->print(" desired_plab_sz = %d) ", plab_sz); | |
| 113 if (ResizePLAB) { | |
| 114 _desired_plab_sz = plab_sz; | |
| 115 } | |
| 116 // Now clear the accumulators for next round: | |
| 117 // note this needs to be fixed in the case where we | |
| 118 // are retaining across scavenges. FIX ME !!! XXX | |
| 119 _allocated = 0; | |
| 120 _wasted = 0; | |
| 121 _unused = 0; | |
| 122 } | |
| 123 | |
| 124 #ifndef PRODUCT | |
| 125 void ParGCAllocBuffer::print() { | |
| 126 gclog_or_tty->print("parGCAllocBuffer: _bottom: %p _top: %p _end: %p _hard_end: %p" | |
| 127 "_retained: %c _retained_filler: [%p,%p)\n", | |
| 128 _bottom, _top, _end, _hard_end, | |
| 129 "FT"[_retained], _retained_filler.start(), _retained_filler.end()); | |
| 130 } | |
| 131 #endif // !PRODUCT | |
| 132 | |
| 133 const size_t ParGCAllocBufferWithBOT::ChunkSizeInWords = | |
| 134 MIN2(CardTableModRefBS::par_chunk_heapword_alignment(), | |
| 135 ((size_t)Generation::GenGrain)/HeapWordSize); | |
| 136 const size_t ParGCAllocBufferWithBOT::ChunkSizeInBytes = | |
| 137 MIN2(CardTableModRefBS::par_chunk_heapword_alignment() * HeapWordSize, | |
| 138 (size_t)Generation::GenGrain); | |
| 139 | |
| 140 ParGCAllocBufferWithBOT::ParGCAllocBufferWithBOT(size_t word_sz, | |
| 141 BlockOffsetSharedArray* bsa) : | |
| 142 ParGCAllocBuffer(word_sz), | |
| 143 _bsa(bsa), | |
| 144 _bt(bsa, MemRegion(_bottom, _hard_end)), | |
| 145 _true_end(_hard_end) | |
| 146 {} | |
| 147 | |
| 148 // The buffer comes with its own BOT, with a shared (obviously) underlying | |
| 149 // BlockOffsetSharedArray. We manipulate this BOT in the normal way | |
| 150 // as we would for any contiguous space. However, on accasion we | |
| 151 // need to do some buffer surgery at the extremities before we | |
| 152 // start using the body of the buffer for allocations. Such surgery | |
| 153 // (as explained elsewhere) is to prevent allocation on a card that | |
| 154 // is in the process of being walked concurrently by another GC thread. | |
| 155 // When such surgery happens at a point that is far removed (to the | |
| 156 // right of the current allocation point, top), we use the "contig" | |
| 157 // parameter below to directly manipulate the shared array without | |
| 158 // modifying the _next_threshold state in the BOT. | |
| 159 void ParGCAllocBufferWithBOT::fill_region_with_block(MemRegion mr, | |
| 160 bool contig) { | |
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161 CollectedHeap::fill_with_object(mr); |
| 0 | 162 if (contig) { |
| 163 _bt.alloc_block(mr.start(), mr.end()); | |
| 164 } else { | |
| 165 _bt.BlockOffsetArray::alloc_block(mr.start(), mr.end()); | |
| 166 } | |
| 167 } | |
| 168 | |
| 169 HeapWord* ParGCAllocBufferWithBOT::allocate_slow(size_t word_sz) { | |
| 170 HeapWord* res = NULL; | |
| 171 if (_true_end > _hard_end) { | |
| 172 assert((HeapWord*)align_size_down(intptr_t(_hard_end), | |
| 173 ChunkSizeInBytes) == _hard_end, | |
| 174 "or else _true_end should be equal to _hard_end"); | |
| 175 assert(_retained, "or else _true_end should be equal to _hard_end"); | |
| 176 assert(_retained_filler.end() <= _top, "INVARIANT"); | |
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177 CollectedHeap::fill_with_object(_retained_filler); |
| 0 | 178 if (_top < _hard_end) { |
| 179 fill_region_with_block(MemRegion(_top, _hard_end), true); | |
| 180 } | |
| 181 HeapWord* next_hard_end = MIN2(_true_end, _hard_end + ChunkSizeInWords); | |
| 182 _retained_filler = MemRegion(_hard_end, FillerHeaderSize); | |
| 183 _bt.alloc_block(_retained_filler.start(), _retained_filler.word_size()); | |
| 184 _top = _retained_filler.end(); | |
| 185 _hard_end = next_hard_end; | |
| 186 _end = _hard_end - AlignmentReserve; | |
| 187 res = ParGCAllocBuffer::allocate(word_sz); | |
| 188 if (res != NULL) { | |
| 189 _bt.alloc_block(res, word_sz); | |
| 190 } | |
| 191 } | |
| 192 return res; | |
| 193 } | |
| 194 | |
| 195 void | |
| 196 ParGCAllocBufferWithBOT::undo_allocation(HeapWord* obj, size_t word_sz) { | |
| 197 ParGCAllocBuffer::undo_allocation(obj, word_sz); | |
| 198 // This may back us up beyond the previous threshold, so reset. | |
| 199 _bt.set_region(MemRegion(_top, _hard_end)); | |
| 200 _bt.initialize_threshold(); | |
| 201 } | |
| 202 | |
| 203 void ParGCAllocBufferWithBOT::retire(bool end_of_gc, bool retain) { | |
| 204 assert(!retain || end_of_gc, "Can only retain at GC end."); | |
| 205 if (_retained) { | |
| 206 // We're about to make the retained_filler into a block. | |
| 207 _bt.BlockOffsetArray::alloc_block(_retained_filler.start(), | |
| 208 _retained_filler.end()); | |
| 209 } | |
| 210 // Reset _hard_end to _true_end (and update _end) | |
| 211 if (retain && _hard_end != NULL) { | |
| 212 assert(_hard_end <= _true_end, "Invariant."); | |
| 213 _hard_end = _true_end; | |
| 214 _end = MAX2(_top, _hard_end - AlignmentReserve); | |
| 215 assert(_end <= _hard_end, "Invariant."); | |
| 216 } | |
| 217 _true_end = _hard_end; | |
| 218 HeapWord* pre_top = _top; | |
| 219 | |
| 220 ParGCAllocBuffer::retire(end_of_gc, retain); | |
| 221 // Now any old _retained_filler is cut back to size, the free part is | |
| 222 // filled with a filler object, and top is past the header of that | |
| 223 // object. | |
| 224 | |
| 225 if (retain && _top < _end) { | |
| 226 assert(end_of_gc && retain, "Or else retain should be false."); | |
| 227 // If the lab does not start on a card boundary, we don't want to | |
| 228 // allocate onto that card, since that might lead to concurrent | |
| 229 // allocation and card scanning, which we don't support. So we fill | |
| 230 // the first card with a garbage object. | |
| 231 size_t first_card_index = _bsa->index_for(pre_top); | |
| 232 HeapWord* first_card_start = _bsa->address_for_index(first_card_index); | |
| 233 if (first_card_start < pre_top) { | |
| 234 HeapWord* second_card_start = | |
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235 _bsa->inc_by_region_size(first_card_start); |
| 0 | 236 |
| 237 // Ensure enough room to fill with the smallest block | |
| 238 second_card_start = MAX2(second_card_start, pre_top + AlignmentReserve); | |
| 239 | |
| 240 // If the end is already in the first card, don't go beyond it! | |
| 241 // Or if the remainder is too small for a filler object, gobble it up. | |
| 242 if (_hard_end < second_card_start || | |
| 243 pointer_delta(_hard_end, second_card_start) < AlignmentReserve) { | |
| 244 second_card_start = _hard_end; | |
| 245 } | |
| 246 if (pre_top < second_card_start) { | |
| 247 MemRegion first_card_suffix(pre_top, second_card_start); | |
| 248 fill_region_with_block(first_card_suffix, true); | |
| 249 } | |
| 250 pre_top = second_card_start; | |
| 251 _top = pre_top; | |
| 252 _end = MAX2(_top, _hard_end - AlignmentReserve); | |
| 253 } | |
| 254 | |
| 255 // If the lab does not end on a card boundary, we don't want to | |
| 256 // allocate onto that card, since that might lead to concurrent | |
| 257 // allocation and card scanning, which we don't support. So we fill | |
| 258 // the last card with a garbage object. | |
| 259 size_t last_card_index = _bsa->index_for(_hard_end); | |
| 260 HeapWord* last_card_start = _bsa->address_for_index(last_card_index); | |
| 261 if (last_card_start < _hard_end) { | |
| 262 | |
| 263 // Ensure enough room to fill with the smallest block | |
| 264 last_card_start = MIN2(last_card_start, _hard_end - AlignmentReserve); | |
| 265 | |
| 266 // If the top is already in the last card, don't go back beyond it! | |
| 267 // Or if the remainder is too small for a filler object, gobble it up. | |
| 268 if (_top > last_card_start || | |
| 269 pointer_delta(last_card_start, _top) < AlignmentReserve) { | |
| 270 last_card_start = _top; | |
| 271 } | |
| 272 if (last_card_start < _hard_end) { | |
| 273 MemRegion last_card_prefix(last_card_start, _hard_end); | |
| 274 fill_region_with_block(last_card_prefix, false); | |
| 275 } | |
| 276 _hard_end = last_card_start; | |
| 277 _end = MAX2(_top, _hard_end - AlignmentReserve); | |
| 278 _true_end = _hard_end; | |
| 279 assert(_end <= _hard_end, "Invariant."); | |
| 280 } | |
| 281 | |
| 282 // At this point: | |
| 283 // 1) we had a filler object from the original top to hard_end. | |
| 284 // 2) We've filled in any partial cards at the front and back. | |
| 285 if (pre_top < _hard_end) { | |
| 286 // Now we can reset the _bt to do allocation in the given area. | |
| 287 MemRegion new_filler(pre_top, _hard_end); | |
| 288 fill_region_with_block(new_filler, false); | |
| 289 _top = pre_top + ParGCAllocBuffer::FillerHeaderSize; | |
| 290 // If there's no space left, don't retain. | |
| 291 if (_top >= _end) { | |
| 292 _retained = false; | |
| 293 invalidate(); | |
| 294 return; | |
| 295 } | |
| 296 _retained_filler = MemRegion(pre_top, _top); | |
| 297 _bt.set_region(MemRegion(_top, _hard_end)); | |
| 298 _bt.initialize_threshold(); | |
| 299 assert(_bt.threshold() > _top, "initialize_threshold failed!"); | |
| 300 | |
| 301 // There may be other reasons for queries into the middle of the | |
| 302 // filler object. When such queries are done in parallel with | |
| 303 // allocation, bad things can happen, if the query involves object | |
| 304 // iteration. So we ensure that such queries do not involve object | |
| 305 // iteration, by putting another filler object on the boundaries of | |
| 306 // such queries. One such is the object spanning a parallel card | |
| 307 // chunk boundary. | |
| 308 | |
| 309 // "chunk_boundary" is the address of the first chunk boundary less | |
| 310 // than "hard_end". | |
| 311 HeapWord* chunk_boundary = | |
| 312 (HeapWord*)align_size_down(intptr_t(_hard_end-1), ChunkSizeInBytes); | |
| 313 assert(chunk_boundary < _hard_end, "Or else above did not work."); | |
| 314 assert(pointer_delta(_true_end, chunk_boundary) >= AlignmentReserve, | |
| 315 "Consequence of last card handling above."); | |
| 316 | |
| 317 if (_top <= chunk_boundary) { | |
| 318 assert(_true_end == _hard_end, "Invariant."); | |
| 319 while (_top <= chunk_boundary) { | |
| 320 assert(pointer_delta(_hard_end, chunk_boundary) >= AlignmentReserve, | |
| 321 "Consequence of last card handling above."); | |
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322 _bt.BlockOffsetArray::alloc_block(chunk_boundary, _hard_end); |
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323 CollectedHeap::fill_with_object(chunk_boundary, _hard_end); |
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324 _hard_end = chunk_boundary; |
| 0 | 325 chunk_boundary -= ChunkSizeInWords; |
| 326 } | |
| 327 _end = _hard_end - AlignmentReserve; | |
| 328 assert(_top <= _end, "Invariant."); | |
| 329 // Now reset the initial filler chunk so it doesn't overlap with | |
| 330 // the one(s) inserted above. | |
| 331 MemRegion new_filler(pre_top, _hard_end); | |
| 332 fill_region_with_block(new_filler, false); | |
| 333 } | |
| 334 } else { | |
| 335 _retained = false; | |
| 336 invalidate(); | |
| 337 } | |
| 338 } else { | |
| 339 assert(!end_of_gc || | |
| 340 (!_retained && _true_end == _hard_end), "Checking."); | |
| 341 } | |
| 342 assert(_end <= _hard_end, "Invariant."); | |
| 343 assert(_top < _end || _top == _hard_end, "Invariant"); | |
| 344 } |