Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/shared/parGCAllocBuffer.hpp @ 20756:060cdf93040c jdk8u31-b04
8055479: TLAB stability
Reviewed-by: brutisso, stefank, ahgross
author | mgerdin |
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date | Thu, 09 Oct 2014 15:42:23 +0200 |
parents | cfd4aac53239 |
children | c2844108a708 |
rev | line source |
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0 | 1 /* |
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2 * Copyright (c) 2001, 2013, 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 #ifndef SHARE_VM_GC_IMPLEMENTATION_PARNEW_PARGCALLOCBUFFER_HPP |
26 #define SHARE_VM_GC_IMPLEMENTATION_PARNEW_PARGCALLOCBUFFER_HPP | |
27 | |
28 #include "memory/allocation.hpp" | |
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29 #include "memory/blockOffsetTable.hpp" |
1972 | 30 #include "memory/threadLocalAllocBuffer.hpp" |
31 #include "utilities/globalDefinitions.hpp" | |
32 | |
0 | 33 // Forward decl. |
34 | |
35 class PLABStats; | |
36 | |
37 // A per-thread allocation buffer used during GC. | |
6197 | 38 class ParGCAllocBuffer: public CHeapObj<mtGC> { |
0 | 39 protected: |
40 char head[32]; | |
41 size_t _word_sz; // in HeapWord units | |
42 HeapWord* _bottom; | |
43 HeapWord* _top; | |
44 HeapWord* _end; // last allocatable address + 1 | |
45 HeapWord* _hard_end; // _end + AlignmentReserve | |
46 bool _retained; // whether we hold a _retained_filler | |
47 MemRegion _retained_filler; | |
48 // In support of ergonomic sizing of PLAB's | |
49 size_t _allocated; // in HeapWord units | |
50 size_t _wasted; // in HeapWord units | |
51 char tail[32]; | |
113
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52 static size_t FillerHeaderSize; |
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53 static size_t AlignmentReserve; |
0 | 54 |
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55 // Flush the stats supporting ergonomic sizing of PLAB's |
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56 // Should not be called directly |
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57 void flush_stats(PLABStats* stats); |
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58 |
0 | 59 public: |
60 // Initializes the buffer to be empty, but with the given "word_sz". | |
61 // Must get initialized with "set_buf" for an allocation to succeed. | |
62 ParGCAllocBuffer(size_t word_sz); | |
63 | |
64 static const size_t min_size() { | |
20756 | 65 // Make sure that we return something that is larger than AlignmentReserve |
66 return align_object_size(MAX2(MinTLABSize / HeapWordSize, (uintx)oopDesc::header_size())) + AlignmentReserve; | |
0 | 67 } |
68 | |
69 static const size_t max_size() { | |
70 return ThreadLocalAllocBuffer::max_size(); | |
71 } | |
72 | |
73 // If an allocation of the given "word_sz" can be satisfied within the | |
74 // buffer, do the allocation, returning a pointer to the start of the | |
75 // allocated block. If the allocation request cannot be satisfied, | |
76 // return NULL. | |
77 HeapWord* allocate(size_t word_sz) { | |
78 HeapWord* res = _top; | |
634 | 79 if (pointer_delta(_end, _top) >= word_sz) { |
80 _top = _top + word_sz; | |
0 | 81 return res; |
82 } else { | |
83 return NULL; | |
84 } | |
85 } | |
86 | |
87 // Undo the last allocation in the buffer, which is required to be of the | |
88 // "obj" of the given "word_sz". | |
89 void undo_allocation(HeapWord* obj, size_t word_sz) { | |
634 | 90 assert(pointer_delta(_top, _bottom) >= word_sz, "Bad undo"); |
91 assert(pointer_delta(_top, obj) == word_sz, "Bad undo"); | |
92 _top = obj; | |
0 | 93 } |
94 | |
95 // The total (word) size of the buffer, including both allocated and | |
96 // unallocted space. | |
97 size_t word_sz() { return _word_sz; } | |
98 | |
99 // Should only be done if we are about to reset with a new buffer of the | |
100 // given size. | |
101 void set_word_size(size_t new_word_sz) { | |
102 assert(new_word_sz > AlignmentReserve, "Too small"); | |
103 _word_sz = new_word_sz; | |
104 } | |
105 | |
106 // The number of words of unallocated space remaining in the buffer. | |
107 size_t words_remaining() { | |
108 assert(_end >= _top, "Negative buffer"); | |
109 return pointer_delta(_end, _top, HeapWordSize); | |
110 } | |
111 | |
112 bool contains(void* addr) { | |
113 return (void*)_bottom <= addr && addr < (void*)_hard_end; | |
114 } | |
115 | |
116 // Sets the space of the buffer to be [buf, space+word_sz()). | |
117 void set_buf(HeapWord* buf) { | |
118 _bottom = buf; | |
119 _top = _bottom; | |
120 _hard_end = _bottom + word_sz(); | |
121 _end = _hard_end - AlignmentReserve; | |
122 assert(_end >= _top, "Negative buffer"); | |
123 // In support of ergonomic sizing | |
124 _allocated += word_sz(); | |
125 } | |
126 | |
127 // Flush the stats supporting ergonomic sizing of PLAB's | |
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128 // and retire the current buffer. |
6595 | 129 void flush_stats_and_retire(PLABStats* stats, bool end_of_gc, bool retain) { |
0 | 130 // We flush the stats first in order to get a reading of |
131 // unused space in the last buffer. | |
132 if (ResizePLAB) { | |
133 flush_stats(stats); | |
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134 |
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135 // Since we have flushed the stats we need to clear |
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136 // the _allocated and _wasted fields. Not doing so |
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137 // will artifically inflate the values in the stats |
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138 // to which we add them. |
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139 // The next time we flush these values, we will add |
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140 // what we have just flushed in addition to the size |
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141 // of the buffers allocated between now and then. |
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142 _allocated = 0; |
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143 _wasted = 0; |
0 | 144 } |
145 // Retire the last allocation buffer. | |
6595 | 146 retire(end_of_gc, retain); |
0 | 147 } |
148 | |
149 // Force future allocations to fail and queries for contains() | |
150 // to return false | |
151 void invalidate() { | |
152 assert(!_retained, "Shouldn't retain an invalidated buffer."); | |
153 _end = _hard_end; | |
154 _wasted += pointer_delta(_end, _top); // unused space | |
155 _top = _end; // force future allocations to fail | |
156 _bottom = _end; // force future contains() queries to return false | |
157 } | |
158 | |
159 // Fills in the unallocated portion of the buffer with a garbage object. | |
160 // If "end_of_gc" is TRUE, is after the last use in the GC. IF "retain" | |
161 // is true, attempt to re-use the unused portion in the next GC. | |
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162 void retire(bool end_of_gc, bool retain); |
0 | 163 |
164 void print() PRODUCT_RETURN; | |
165 }; | |
166 | |
167 // PLAB stats book-keeping | |
168 class PLABStats VALUE_OBJ_CLASS_SPEC { | |
169 size_t _allocated; // total allocated | |
170 size_t _wasted; // of which wasted (internal fragmentation) | |
171 size_t _unused; // Unused in last buffer | |
172 size_t _used; // derived = allocated - wasted - unused | |
173 size_t _desired_plab_sz;// output of filter (below), suitably trimmed and quantized | |
174 AdaptiveWeightedAverage | |
175 _filter; // integrator with decay | |
176 | |
177 public: | |
178 PLABStats(size_t desired_plab_sz_, unsigned wt) : | |
179 _allocated(0), | |
180 _wasted(0), | |
181 _unused(0), | |
182 _used(0), | |
183 _desired_plab_sz(desired_plab_sz_), | |
184 _filter(wt) | |
17727 | 185 { } |
0 | 186 |
187 static const size_t min_size() { | |
188 return ParGCAllocBuffer::min_size(); | |
189 } | |
190 | |
191 static const size_t max_size() { | |
192 return ParGCAllocBuffer::max_size(); | |
193 } | |
194 | |
195 size_t desired_plab_sz() { | |
196 return _desired_plab_sz; | |
197 } | |
198 | |
6819 | 199 void adjust_desired_plab_sz(uint no_of_gc_workers); |
200 // filter computation, latches output to | |
0 | 201 // _desired_plab_sz, clears sensor accumulators |
202 | |
203 void add_allocated(size_t v) { | |
204 Atomic::add_ptr(v, &_allocated); | |
205 } | |
206 | |
207 void add_unused(size_t v) { | |
208 Atomic::add_ptr(v, &_unused); | |
209 } | |
210 | |
211 void add_wasted(size_t v) { | |
212 Atomic::add_ptr(v, &_wasted); | |
213 } | |
214 }; | |
215 | |
216 class ParGCAllocBufferWithBOT: public ParGCAllocBuffer { | |
217 BlockOffsetArrayContigSpace _bt; | |
218 BlockOffsetSharedArray* _bsa; | |
219 HeapWord* _true_end; // end of the whole ParGCAllocBuffer | |
220 | |
221 static const size_t ChunkSizeInWords; | |
222 static const size_t ChunkSizeInBytes; | |
223 HeapWord* allocate_slow(size_t word_sz); | |
224 | |
225 void fill_region_with_block(MemRegion mr, bool contig); | |
226 | |
227 public: | |
228 ParGCAllocBufferWithBOT(size_t word_sz, BlockOffsetSharedArray* bsa); | |
229 | |
230 HeapWord* allocate(size_t word_sz) { | |
231 HeapWord* res = ParGCAllocBuffer::allocate(word_sz); | |
232 if (res != NULL) { | |
233 _bt.alloc_block(res, word_sz); | |
234 } else { | |
235 res = allocate_slow(word_sz); | |
236 } | |
237 return res; | |
238 } | |
239 | |
240 void undo_allocation(HeapWord* obj, size_t word_sz); | |
241 | |
242 void set_buf(HeapWord* buf_start) { | |
243 ParGCAllocBuffer::set_buf(buf_start); | |
244 _true_end = _hard_end; | |
245 _bt.set_region(MemRegion(buf_start, word_sz())); | |
246 _bt.initialize_threshold(); | |
247 } | |
248 | |
249 void retire(bool end_of_gc, bool retain); | |
250 | |
251 MemRegion range() { | |
252 return MemRegion(_top, _true_end); | |
253 } | |
254 }; | |
1972 | 255 |
256 #endif // SHARE_VM_GC_IMPLEMENTATION_PARNEW_PARGCALLOCBUFFER_HPP |