1 /* 2 * Copyright (c) 2014, 2015, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1ALLOCATOR_HPP 26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1ALLOCATOR_HPP 27 28 #include "gc_implementation/g1/g1AllocationContext.hpp" 29 #include "gc_implementation/g1/g1AllocRegion.hpp" 30 #include "gc_implementation/g1/g1InCSetState.hpp" 31 #include "gc_implementation/shared/parGCAllocBuffer.hpp" 32 #include "gc_interface/collectedHeap.hpp" 33 34 class EvacuationInfo; 35 36 // Base class for G1 allocators. 37 class G1Allocator : public CHeapObj<mtGC> { 38 friend class VMStructs; 39 protected: 40 G1CollectedHeap* _g1h; 41 42 // Outside of GC pauses, the number of bytes used in all regions other 43 // than the current allocation region. 44 size_t _summary_bytes_used; 45 46 public: 47 G1Allocator(G1CollectedHeap* heap) : 48 _g1h(heap), _summary_bytes_used(0) { } 49 50 static G1Allocator* create_allocator(G1CollectedHeap* g1h); 51 52 virtual void init_mutator_alloc_region() = 0; 53 virtual void release_mutator_alloc_region() = 0; 54 55 virtual void init_gc_alloc_regions(EvacuationInfo& evacuation_info) = 0; 56 virtual void release_gc_alloc_regions(uint no_of_gc_workers, EvacuationInfo& evacuation_info) = 0; 57 virtual void abandon_gc_alloc_regions() = 0; 58 59 virtual MutatorAllocRegion* mutator_alloc_region(AllocationContext_t context) = 0; 60 virtual SurvivorGCAllocRegion* survivor_gc_alloc_region(AllocationContext_t context) = 0; 61 virtual OldGCAllocRegion* old_gc_alloc_region(AllocationContext_t context) = 0; 62 virtual size_t used() = 0; 63 virtual bool is_retained_old_region(HeapRegion* hr) = 0; 64 65 void reuse_retained_old_region(EvacuationInfo& evacuation_info, 66 OldGCAllocRegion* old, 67 HeapRegion** retained); 68 69 size_t used_unlocked() const { 70 return _summary_bytes_used; 71 } 72 73 void increase_used(size_t bytes) { 74 _summary_bytes_used += bytes; 75 } 76 77 void decrease_used(size_t bytes) { 78 assert(_summary_bytes_used >= bytes, 79 err_msg("invariant: _summary_bytes_used: "SIZE_FORMAT" should be >= bytes: "SIZE_FORMAT, 80 _summary_bytes_used, bytes)); 81 _summary_bytes_used -= bytes; 82 } 83 84 void set_used(size_t bytes) { 85 _summary_bytes_used = bytes; 86 } 87 88 virtual HeapRegion* new_heap_region(uint hrs_index, 89 G1BlockOffsetSharedArray* sharedOffsetArray, 90 MemRegion mr) { 91 return new HeapRegion(hrs_index, sharedOffsetArray, mr); 92 } 93 }; 94 95 // The default allocator for G1. 96 class G1DefaultAllocator : public G1Allocator { 97 protected: 98 // Alloc region used to satisfy mutator allocation requests. 99 MutatorAllocRegion _mutator_alloc_region; 100 101 // Alloc region used to satisfy allocation requests by the GC for 102 // survivor objects. 103 SurvivorGCAllocRegion _survivor_gc_alloc_region; 104 105 // Alloc region used to satisfy allocation requests by the GC for 106 // old objects. 107 OldGCAllocRegion _old_gc_alloc_region; 108 109 HeapRegion* _retained_old_gc_alloc_region; 110 public: 111 G1DefaultAllocator(G1CollectedHeap* heap) : G1Allocator(heap), _retained_old_gc_alloc_region(NULL) { } 112 113 virtual void init_mutator_alloc_region(); 114 virtual void release_mutator_alloc_region(); 115 116 virtual void init_gc_alloc_regions(EvacuationInfo& evacuation_info); 117 virtual void release_gc_alloc_regions(uint no_of_gc_workers, EvacuationInfo& evacuation_info); 118 virtual void abandon_gc_alloc_regions(); 119 120 virtual bool is_retained_old_region(HeapRegion* hr) { 121 return _retained_old_gc_alloc_region == hr; 122 } 123 124 virtual MutatorAllocRegion* mutator_alloc_region(AllocationContext_t context) { 125 return &_mutator_alloc_region; 126 } 127 128 virtual SurvivorGCAllocRegion* survivor_gc_alloc_region(AllocationContext_t context) { 129 return &_survivor_gc_alloc_region; 130 } 131 132 virtual OldGCAllocRegion* old_gc_alloc_region(AllocationContext_t context) { 133 return &_old_gc_alloc_region; 134 } 135 136 virtual size_t used() { 137 assert(Heap_lock->owner() != NULL, 138 "Should be owned on this thread's behalf."); 139 size_t result = _summary_bytes_used; 140 141 // Read only once in case it is set to NULL concurrently 142 HeapRegion* hr = mutator_alloc_region(AllocationContext::current())->get(); 143 if (hr != NULL) { 144 result += hr->used(); 145 } 146 return result; 147 } 148 }; 149 150 class G1PLABWasteStat VALUE_OBJ_CLASS_SPEC { 151 private: 152 size_t _wasted; 153 size_t _undo_wasted; 154 public: 155 156 G1PLABWasteStat() : _wasted(0), _undo_wasted(0) { 157 } 158 159 void add_wasted(size_t word_sz) { 160 _wasted += word_sz; 161 } 162 163 void add_undo_wasted(size_t word_sz) { 164 _undo_wasted += word_sz; 165 } 166 167 size_t wasted() { 168 return _wasted; 169 } 170 171 size_t undo_wasted() { 172 return _undo_wasted; 173 } 174 }; 175 176 class G1ParGCAllocBuffer: public ParGCAllocBuffer { 177 private: 178 bool _retired; 179 180 public: 181 G1ParGCAllocBuffer(size_t gclab_word_size); 182 virtual ~G1ParGCAllocBuffer() { 183 guarantee(_retired, "Allocation buffer has not been retired"); 184 } 185 186 virtual void set_buf(HeapWord* buf) { 187 ParGCAllocBuffer::set_buf(buf); 188 _retired = false; 189 } 190 191 virtual void retire() { 192 if (_retired) { 193 return; 194 } 195 ParGCAllocBuffer::retire(); 196 _retired = true; 197 } 198 }; 199 200 class G1ParGCAllocator : public CHeapObj<mtGC> { 201 friend class G1ParScanThreadState; 202 protected: 203 G1CollectedHeap* _g1h; 204 205 // The survivor alignment in effect in bytes. 206 // == 0 : don't align survivors 207 // != 0 : align survivors to that alignment 208 // These values were chosen to favor the non-alignment case since some 209 // architectures have a special compare against zero instructions. 210 const uint _survivor_alignment_bytes; 211 212 virtual void retire_alloc_buffers() = 0; 213 virtual G1ParGCAllocBuffer* alloc_buffer(InCSetState dest, AllocationContext_t context) = 0; 214 215 // Calculate the survivor space object alignment in bytes. Returns that or 0 if 216 // there are no restrictions on survivor alignment. 217 static uint calc_survivor_alignment_bytes() { 218 assert(SurvivorAlignmentInBytes >= ObjectAlignmentInBytes, "sanity"); 219 if (SurvivorAlignmentInBytes == ObjectAlignmentInBytes) { 220 // No need to align objects in the survivors differently, return 0 221 // which means "survivor alignment is not used". 222 return 0; 223 } else { 224 assert(SurvivorAlignmentInBytes > 0, "sanity"); 225 return SurvivorAlignmentInBytes; 226 } 227 } 228 229 public: 230 G1ParGCAllocator(G1CollectedHeap* g1h) : 231 _g1h(g1h), _survivor_alignment_bytes(calc_survivor_alignment_bytes()) { 232 } 233 234 static G1ParGCAllocator* create_allocator(G1CollectedHeap* g1h); 235 236 virtual G1PLABWasteStat wasted() = 0; 237 238 // Allocate word_sz words in dest, either directly into the regions or by 239 // allocating a new PLAB. Returns the address of the allocated memory, NULL if 240 // not successful. 241 HeapWord* allocate_direct_or_new_plab(InCSetState dest, 242 size_t word_sz, 243 AllocationContext_t context); 244 245 // Allocate word_sz words in the PLAB of dest. Returns the address of the 246 // allocated memory, NULL if not successful. 247 HeapWord* plab_allocate(InCSetState dest, 248 size_t word_sz, 249 AllocationContext_t context) { 250 G1ParGCAllocBuffer* buffer = alloc_buffer(dest, context); 251 if (_survivor_alignment_bytes == 0) { 252 return buffer->allocate(word_sz); 253 } else { 254 return buffer->allocate_aligned(word_sz, _survivor_alignment_bytes); 255 } 256 } 257 258 HeapWord* allocate(InCSetState dest, size_t word_sz, 259 AllocationContext_t context) { 260 HeapWord* const obj = plab_allocate(dest, word_sz, context); 261 if (obj != NULL) { 262 return obj; 263 } 264 return allocate_direct_or_new_plab(dest, word_sz, context); 265 } 266 267 void undo_allocation(InCSetState dest, HeapWord* obj, size_t word_sz, AllocationContext_t context) { 268 alloc_buffer(dest, context)->undo_allocation(obj, word_sz); 269 } 270 }; 271 272 class G1DefaultParGCAllocator : public G1ParGCAllocator { 273 G1ParGCAllocBuffer _surviving_alloc_buffer; 274 G1ParGCAllocBuffer _tenured_alloc_buffer; 275 G1ParGCAllocBuffer* _alloc_buffers[InCSetState::Num]; 276 277 public: 278 G1DefaultParGCAllocator(G1CollectedHeap* g1h); 279 280 virtual G1ParGCAllocBuffer* alloc_buffer(InCSetState dest, AllocationContext_t context) { 281 assert(dest.is_valid(), 282 err_msg("Allocation buffer index out-of-bounds: " CSETSTATE_FORMAT, dest.value())); 283 assert(_alloc_buffers[dest.value()] != NULL, 284 err_msg("Allocation buffer is NULL: " CSETSTATE_FORMAT, dest.value())); 285 return _alloc_buffers[dest.value()]; 286 } 287 288 virtual void retire_alloc_buffers(); 289 290 virtual G1PLABWasteStat wasted(); 291 }; 292 293 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1ALLOCATOR_HPP