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 // Interface to keep track of which regions G1 is currently allocating into. Provides 37 // some accessors (e.g. allocating into them, or getting their occupancy). 38 // Also keeps track of retained regions across GCs. 39 class G1Allocator : public CHeapObj<mtGC> { 40 friend class VMStructs; 41 private: 42 bool _survivor_is_full; 43 bool _old_is_full; 44 protected: 45 G1CollectedHeap* _g1h; 46 47 virtual MutatorAllocRegion* mutator_alloc_region(AllocationContext_t context) = 0; 48 49 virtual bool survivor_is_full(AllocationContext_t context) const; 50 virtual bool old_is_full(AllocationContext_t context) const; 51 52 virtual void set_survivor_full(AllocationContext_t context); 53 virtual void set_old_full(AllocationContext_t context); 54 55 // Accessors to the allocation regions. 56 virtual SurvivorGCAllocRegion* survivor_gc_alloc_region(AllocationContext_t context) = 0; 57 virtual OldGCAllocRegion* old_gc_alloc_region(AllocationContext_t context) = 0; 58 59 // Allocation attempt during GC for a survivor object / PLAB. 60 inline HeapWord* survivor_attempt_allocation(size_t min_word_size, 61 size_t desired_word_size, 62 size_t* actual_word_size, 63 AllocationContext_t context); 64 // Allocation attempt during GC for an old object / PLAB. 65 inline HeapWord* old_attempt_allocation(size_t min_word_size, 66 size_t desired_word_size, 67 size_t* actual_word_size, 68 AllocationContext_t context); 69 public: 70 G1Allocator(G1CollectedHeap* heap) : _g1h(heap), _survivor_is_full(false), _old_is_full(false) { } 71 virtual ~G1Allocator() { } 72 73 static G1Allocator* create_allocator(G1CollectedHeap* g1h); 74 75 #ifdef ASSERT 76 // Do we currently have an active mutator region to allocate into? 77 bool has_mutator_alloc_region(AllocationContext_t context) { return mutator_alloc_region(context)->get() != NULL; } 78 #endif 79 virtual void init_mutator_alloc_region() = 0; 80 virtual void release_mutator_alloc_region() = 0; 81 82 virtual void init_gc_alloc_regions(EvacuationInfo& evacuation_info); 83 virtual void release_gc_alloc_regions(EvacuationInfo& evacuation_info) = 0; 84 virtual void abandon_gc_alloc_regions() = 0; 85 86 // Management of retained regions. 87 88 virtual bool is_retained_old_region(HeapRegion* hr) = 0; 89 void reuse_retained_old_region(EvacuationInfo& evacuation_info, 90 OldGCAllocRegion* old, 91 HeapRegion** retained); 92 93 // Allocate blocks of memory during mutator time. 94 95 inline HeapWord* attempt_allocation(size_t word_size, AllocationContext_t context); 96 inline HeapWord* attempt_allocation_locked(size_t word_size, AllocationContext_t context); 97 inline HeapWord* attempt_allocation_force(size_t word_size, AllocationContext_t context); 98 99 size_t unsafe_max_tlab_alloc(AllocationContext_t context); 100 101 // Allocate blocks of memory during garbage collection. Will ensure an 102 // allocation region, either by picking one or expanding the 103 // heap, and then allocate a block of the given size. The block 104 // may not be a humongous - it must fit into a single heap region. 105 HeapWord* par_allocate_during_gc(InCSetState dest, 106 size_t word_size, 107 AllocationContext_t context); 108 109 HeapWord* par_allocate_during_gc(InCSetState dest, 110 size_t min_word_size, 111 size_t desired_word_size, 112 size_t* actual_word_size, 113 AllocationContext_t context); 114 115 virtual size_t used_in_alloc_regions() = 0; 116 }; 117 118 // The default allocation region manager for G1. Provides a single mutator, survivor 119 // and old generation allocation region. 120 // Can retain the (single) old generation allocation region across GCs. 121 class G1DefaultAllocator : public G1Allocator { 122 protected: 123 // Alloc region used to satisfy mutator allocation requests. 124 MutatorAllocRegion _mutator_alloc_region; 125 126 // Alloc region used to satisfy allocation requests by the GC for 127 // survivor objects. 128 SurvivorGCAllocRegion _survivor_gc_alloc_region; 129 130 // Alloc region used to satisfy allocation requests by the GC for 131 // old objects. 132 OldGCAllocRegion _old_gc_alloc_region; 133 134 HeapRegion* _retained_old_gc_alloc_region; 135 public: 136 G1DefaultAllocator(G1CollectedHeap* heap); 137 138 virtual void init_mutator_alloc_region(); 139 virtual void release_mutator_alloc_region(); 140 141 virtual void init_gc_alloc_regions(EvacuationInfo& evacuation_info); 142 virtual void release_gc_alloc_regions(EvacuationInfo& evacuation_info); 143 virtual void abandon_gc_alloc_regions(); 144 145 virtual bool is_retained_old_region(HeapRegion* hr) { 146 return _retained_old_gc_alloc_region == hr; 147 } 148 149 virtual MutatorAllocRegion* mutator_alloc_region(AllocationContext_t context) { 150 return &_mutator_alloc_region; 151 } 152 153 virtual SurvivorGCAllocRegion* survivor_gc_alloc_region(AllocationContext_t context) { 154 return &_survivor_gc_alloc_region; 155 } 156 157 virtual OldGCAllocRegion* old_gc_alloc_region(AllocationContext_t context) { 158 return &_old_gc_alloc_region; 159 } 160 161 virtual size_t used_in_alloc_regions() { 162 assert(Heap_lock->owner() != NULL, 163 "Should be owned on this thread's behalf."); 164 size_t result = 0; 165 166 // Read only once in case it is set to NULL concurrently 167 HeapRegion* hr = mutator_alloc_region(AllocationContext::current())->get(); 168 if (hr != NULL) { 169 result += hr->used(); 170 } 171 return result; 172 } 173 }; 174 175 class G1PLAB: public PLAB { 176 private: 177 bool _retired; 178 179 public: 180 G1PLAB(size_t gclab_word_size); 181 virtual ~G1PLAB() { 182 guarantee(_retired, "Allocation buffer has not been retired"); 183 } 184 185 // The amount of space in words wasted within the PLAB including 186 // waste due to refills and alignment. 187 size_t wasted() const { return _wasted; } 188 189 virtual void set_buf(HeapWord* buf, size_t word_size) { 190 PLAB::set_buf(buf, word_size); 191 _retired = false; 192 } 193 194 virtual void retire() { 195 if (_retired) { 196 return; 197 } 198 PLAB::retire(); 199 _retired = true; 200 } 201 202 virtual void flush_and_retire_stats(PLABStats* stats) { 203 PLAB::flush_and_retire_stats(stats); 204 _retired = true; 205 } 206 }; 207 208 // Manages the PLABs used during garbage collection. Interface for allocation from PLABs. 209 // Needs to handle multiple contexts, extra alignment in any "survivor" area and some 210 // statistics. 211 class G1PLABAllocator : public CHeapObj<mtGC> { 212 friend class G1ParScanThreadState; 213 protected: 214 G1CollectedHeap* _g1h; 215 G1Allocator* _allocator; 216 217 // The survivor alignment in effect in bytes. 218 // == 0 : don't align survivors 219 // != 0 : align survivors to that alignment 220 // These values were chosen to favor the non-alignment case since some 221 // architectures have a special compare against zero instructions. 222 const uint _survivor_alignment_bytes; 223 224 // Number of words allocated directly (not counting PLAB allocation). 225 size_t _direct_allocated[InCSetState::Num]; 226 227 virtual void flush_and_retire_stats() = 0; 228 virtual G1PLAB* alloc_buffer(InCSetState dest, AllocationContext_t context) = 0; 229 230 // Calculate the survivor space object alignment in bytes. Returns that or 0 if 231 // there are no restrictions on survivor alignment. 232 static uint calc_survivor_alignment_bytes() { 233 assert(SurvivorAlignmentInBytes >= ObjectAlignmentInBytes, "sanity"); 234 if (SurvivorAlignmentInBytes == ObjectAlignmentInBytes) { 235 // No need to align objects in the survivors differently, return 0 236 // which means "survivor alignment is not used". 237 return 0; 238 } else { 239 assert(SurvivorAlignmentInBytes > 0, "sanity"); 240 return SurvivorAlignmentInBytes; 241 } 242 } 243 244 HeapWord* allocate_new_plab(InCSetState dest, 245 size_t word_sz, 246 AllocationContext_t context); 247 248 bool may_throw_away_buffer(size_t const allocation_word_sz, size_t const buffer_size) const; 249 public: 250 G1PLABAllocator(G1Allocator* allocator); 251 virtual ~G1PLABAllocator() { } 252 253 static G1PLABAllocator* create_allocator(G1Allocator* allocator); 254 255 virtual void waste(size_t& wasted, size_t& undo_wasted) = 0; 256 257 // Allocate word_sz words in dest, either directly into the regions or by 258 // allocating a new PLAB. Returns the address of the allocated memory, NULL if 259 // not successful. Plab_refill_failed indicates whether an attempt to refill the 260 // PLAB failed or not. 261 HeapWord* allocate_direct_or_new_plab(InCSetState dest, 262 size_t word_sz, 263 AllocationContext_t context, 264 bool* plab_refill_failed); 265 266 // Allocate word_sz words in the PLAB of dest. Returns the address of the 267 // allocated memory, NULL if not successful. 268 inline HeapWord* plab_allocate(InCSetState dest, 269 size_t word_sz, 270 AllocationContext_t context); 271 272 HeapWord* allocate(InCSetState dest, 273 size_t word_sz, 274 AllocationContext_t context, 275 bool* refill_failed) { 276 HeapWord* const obj = plab_allocate(dest, word_sz, context); 277 if (obj != NULL) { 278 return obj; 279 } 280 return allocate_direct_or_new_plab(dest, word_sz, context, refill_failed); 281 } 282 283 void undo_allocation(InCSetState dest, HeapWord* obj, size_t word_sz, AllocationContext_t context); 284 }; 285 286 // The default PLAB allocator for G1. Keeps the current (single) PLAB for survivor 287 // and old generation allocation. 288 class G1DefaultPLABAllocator : public G1PLABAllocator { 289 G1PLAB _surviving_alloc_buffer; 290 G1PLAB _tenured_alloc_buffer; 291 G1PLAB* _alloc_buffers[InCSetState::Num]; 292 293 public: 294 G1DefaultPLABAllocator(G1Allocator* _allocator); 295 296 virtual G1PLAB* alloc_buffer(InCSetState dest, AllocationContext_t context) { 297 assert(dest.is_valid(), 298 "Allocation buffer index out-of-bounds: " CSETSTATE_FORMAT, dest.value()); 299 assert(_alloc_buffers[dest.value()] != NULL, 300 "Allocation buffer is NULL: " CSETSTATE_FORMAT, dest.value()); 301 return _alloc_buffers[dest.value()]; 302 } 303 304 virtual void flush_and_retire_stats(); 305 306 virtual void waste(size_t& wasted, size_t& undo_wasted); 307 }; 308 309 // G1ArchiveAllocator is used to allocate memory in archive 310 // regions. Such regions are not modifiable by GC, being neither 311 // scavenged nor compacted, or even marked in the object header. 312 // They can contain no pointers to non-archive heap regions, 313 class G1ArchiveAllocator : public CHeapObj<mtGC> { 314 315 protected: 316 G1CollectedHeap* _g1h; 317 318 // The current allocation region 319 HeapRegion* _allocation_region; 320 321 // Regions allocated for the current archive range. 322 GrowableArray<HeapRegion*> _allocated_regions; 323 324 // The number of bytes used in the current range. 325 size_t _summary_bytes_used; 326 327 // Current allocation window within the current region. 328 HeapWord* _bottom; 329 HeapWord* _top; 330 HeapWord* _max; 331 332 // Allocate a new region for this archive allocator. 333 // Allocation is from the top of the reserved heap downward. 334 bool alloc_new_region(); 335 336 public: 337 G1ArchiveAllocator(G1CollectedHeap* g1h) : 338 _g1h(g1h), 339 _allocation_region(NULL), 340 _allocated_regions((ResourceObj::set_allocation_type((address) &_allocated_regions, 341 ResourceObj::C_HEAP), 342 2), true /* C_Heap */), 343 _summary_bytes_used(0), 344 _bottom(NULL), 345 _top(NULL), 346 _max(NULL) { } 347 348 virtual ~G1ArchiveAllocator() { 349 assert(_allocation_region == NULL, "_allocation_region not NULL"); 350 } 351 352 static G1ArchiveAllocator* create_allocator(G1CollectedHeap* g1h); 353 354 // Allocate memory for an individual object. 355 HeapWord* archive_mem_allocate(size_t word_size); 356 357 // Return the memory ranges used in the current archive, after 358 // aligning to the requested alignment. 359 void complete_archive(GrowableArray<MemRegion>* ranges, 360 size_t end_alignment_in_bytes); 361 362 // The number of bytes allocated by this allocator. 363 size_t used() { 364 return _summary_bytes_used; 365 } 366 367 // Clear the count of bytes allocated in prior G1 regions. This 368 // must be done when recalculate_use is used to reset the counter 369 // for the generic allocator, since it counts bytes in all G1 370 // regions, including those still associated with this allocator. 371 void clear_used() { 372 _summary_bytes_used = 0; 373 } 374 375 }; 376 377 #endif // SHARE_VM_GC_G1_G1ALLOCATOR_HPP