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_G1_G1ALLOCATOR_HPP 26 #define SHARE_VM_GC_G1_G1ALLOCATOR_HPP 27 28 #include "gc/g1/g1AllocRegion.hpp" 29 #include "gc/g1/g1AllocationContext.hpp" 30 #include "gc/g1/g1InCSetState.hpp" 31 #include "gc/shared/collectedHeap.hpp" 32 #include "gc/shared/plab.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(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(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 G1PLAB: public PLAB { 151 private: 152 bool _retired; 153 154 public: 155 G1PLAB(size_t gclab_word_size); 156 virtual ~G1PLAB() { 157 guarantee(_retired, "Allocation buffer has not been retired"); 158 } 159 160 virtual void set_buf(HeapWord* buf) { 161 PLAB::set_buf(buf); 162 _retired = false; 163 } 164 165 virtual void retire() { 166 if (_retired) { 167 return; 168 } 169 PLAB::retire(); 170 _retired = true; 171 } 172 173 virtual void flush_and_retire_stats(PLABStats* stats) { 174 PLAB::flush_and_retire_stats(stats); 175 _retired = true; 176 } 177 }; 178 179 class G1ParGCAllocator : public CHeapObj<mtGC> { 180 friend class G1ParScanThreadState; 181 protected: 182 G1CollectedHeap* _g1h; 183 184 // The survivor alignment in effect in bytes. 185 // == 0 : don't align survivors 186 // != 0 : align survivors to that alignment 187 // These values were chosen to favor the non-alignment case since some 188 // architectures have a special compare against zero instructions. 189 const uint _survivor_alignment_bytes; 190 191 virtual void retire_alloc_buffers() = 0; 192 virtual G1PLAB* alloc_buffer(InCSetState dest, AllocationContext_t context) = 0; 193 194 // Calculate the survivor space object alignment in bytes. Returns that or 0 if 195 // there are no restrictions on survivor alignment. 196 static uint calc_survivor_alignment_bytes() { 197 assert(SurvivorAlignmentInBytes >= ObjectAlignmentInBytes, "sanity"); 198 if (SurvivorAlignmentInBytes == ObjectAlignmentInBytes) { 199 // No need to align objects in the survivors differently, return 0 200 // which means "survivor alignment is not used". 201 return 0; 202 } else { 203 assert(SurvivorAlignmentInBytes > 0, "sanity"); 204 return SurvivorAlignmentInBytes; 205 } 206 } 207 208 public: 209 G1ParGCAllocator(G1CollectedHeap* g1h) : 210 _g1h(g1h), _survivor_alignment_bytes(calc_survivor_alignment_bytes()) { } 211 virtual ~G1ParGCAllocator() { } 212 213 static G1ParGCAllocator* create_allocator(G1CollectedHeap* g1h); 214 215 virtual void waste(size_t& wasted, size_t& undo_wasted) = 0; 216 217 // Allocate word_sz words in dest, either directly into the regions or by 218 // allocating a new PLAB. Returns the address of the allocated memory, NULL if 219 // not successful. 220 HeapWord* allocate_direct_or_new_plab(InCSetState dest, 221 size_t word_sz, 222 AllocationContext_t context); 223 224 // Allocate word_sz words in the PLAB of dest. Returns the address of the 225 // allocated memory, NULL if not successful. 226 HeapWord* plab_allocate(InCSetState dest, 227 size_t word_sz, 228 AllocationContext_t context) { 229 G1PLAB* buffer = alloc_buffer(dest, context); 230 if (_survivor_alignment_bytes == 0 || !dest.is_young()) { 231 return buffer->allocate(word_sz); 232 } else { 233 return buffer->allocate_aligned(word_sz, _survivor_alignment_bytes); 234 } 235 } 236 237 HeapWord* allocate(InCSetState dest, size_t word_sz, 238 AllocationContext_t context) { 239 HeapWord* const obj = plab_allocate(dest, word_sz, context); 240 if (obj != NULL) { 241 return obj; 242 } 243 return allocate_direct_or_new_plab(dest, word_sz, context); 244 } 245 246 void undo_allocation(InCSetState dest, HeapWord* obj, size_t word_sz, AllocationContext_t context) { 247 alloc_buffer(dest, context)->undo_allocation(obj, word_sz); 248 } 249 }; 250 251 class G1DefaultParGCAllocator : public G1ParGCAllocator { 252 G1PLAB _surviving_alloc_buffer; 253 G1PLAB _tenured_alloc_buffer; 254 G1PLAB* _alloc_buffers[InCSetState::Num]; 255 256 public: 257 G1DefaultParGCAllocator(G1CollectedHeap* g1h); 258 259 virtual G1PLAB* alloc_buffer(InCSetState dest, AllocationContext_t context) { 260 assert(dest.is_valid(), 261 err_msg("Allocation buffer index out-of-bounds: " CSETSTATE_FORMAT, dest.value())); 262 assert(_alloc_buffers[dest.value()] != NULL, 263 err_msg("Allocation buffer is NULL: " CSETSTATE_FORMAT, dest.value())); 264 return _alloc_buffers[dest.value()]; 265 } 266 267 virtual void retire_alloc_buffers(); 268 269 virtual void waste(size_t& wasted, size_t& undo_wasted); 270 }; 271 272 // G1ArchiveAllocator is used to allocate memory in archive 273 // regions. Such regions are not modifiable by GC, being neither 274 // scavenged nor compacted, or even marked in the object header. 275 // They can contain no pointers to non-archive heap regions, 276 class G1ArchiveAllocator : public CHeapObj<mtGC> { 277 278 protected: 279 G1CollectedHeap* _g1h; 280 281 // The current allocation region 282 HeapRegion* _allocation_region; 283 284 // Regions allocated for the current archive range. 285 GrowableArray<HeapRegion*> _allocated_regions; 286 287 // The number of bytes used in the current range. 288 size_t _summary_bytes_used; 289 290 // Current allocation window within the current region. 291 HeapWord* _bottom; 292 HeapWord* _top; 293 HeapWord* _max; 294 295 // Allocate a new region for this archive allocator. 296 // Allocation is from the top of the reserved heap downward. 297 bool alloc_new_region(); 298 299 public: 300 G1ArchiveAllocator(G1CollectedHeap* g1h) : 301 _g1h(g1h), 302 _allocation_region(NULL), 303 _allocated_regions((ResourceObj::set_allocation_type((address) &_allocated_regions, 304 ResourceObj::C_HEAP), 305 2), true /* C_Heap */), 306 _summary_bytes_used(0), 307 _bottom(NULL), 308 _top(NULL), 309 _max(NULL) { } 310 311 virtual ~G1ArchiveAllocator() { 312 assert(_allocation_region == NULL, "_allocation_region not NULL"); 313 } 314 315 static G1ArchiveAllocator* create_allocator(G1CollectedHeap* g1h); 316 317 // Allocate memory for an individual object. 318 HeapWord* archive_mem_allocate(size_t word_size); 319 320 // Return the memory ranges used in the current archive, after 321 // aligning to the requested alignment. 322 void complete_archive(GrowableArray<MemRegion>* ranges, 323 size_t end_alignment_in_bytes); 324 325 // The number of bytes allocated by this allocator. 326 size_t used() { 327 return _summary_bytes_used; 328 } 329 330 // Clear the count of bytes allocated in prior G1 regions. This 331 // must be done when recalculate_use is used to reset the counter 332 // for the generic allocator, since it counts bytes in all G1 333 // regions, including those still associated with this allocator. 334 void clear_used() { 335 _summary_bytes_used = 0; 336 } 337 338 }; 339 340 #endif // SHARE_VM_GC_G1_G1ALLOCATOR_HPP