1 /* 2 * Copyright (c) 2014, 2019, 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_GC_G1_G1ALLOCATOR_HPP 26 #define SHARE_GC_G1_G1ALLOCATOR_HPP 27 28 #include "gc/g1/g1AllocRegion.hpp" 29 #include "gc/g1/g1HeapRegionAttr.hpp" 30 #include "gc/shared/collectedHeap.hpp" 31 #include "gc/shared/plab.hpp" 32 33 class G1EvacuationInfo; 34 class G1MemoryNodeManager; 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 42 private: 43 G1CollectedHeap* _g1h; 44 G1MemoryNodeManager* _mnm; 45 46 bool _survivor_is_full; 47 bool _old_is_full; 48 49 // The number of MutatorAllocRegions used, one per memory node. 50 size_t _num_alloc_regions; 51 52 // Alloc region used to satisfy mutator allocation requests. 53 MutatorAllocRegion* _mutator_alloc_regions; 54 55 // Alloc region used to satisfy allocation requests by the GC for 56 // survivor objects. 57 SurvivorGCAllocRegion _survivor_gc_alloc_region; 58 59 // Alloc region used to satisfy allocation requests by the GC for 60 // old objects. 61 OldGCAllocRegion _old_gc_alloc_region; 62 63 HeapRegion* _retained_old_gc_alloc_region; 64 65 bool survivor_is_full() const; 66 bool old_is_full() const; 67 68 void set_survivor_full(); 69 void set_old_full(); 70 71 void reuse_retained_old_region(G1EvacuationInfo& evacuation_info, 72 OldGCAllocRegion* old, 73 HeapRegion** retained); 74 75 // Accessors to the allocation regions. 76 inline MutatorAllocRegion* mutator_alloc_region(uint node_index); 77 inline SurvivorGCAllocRegion* survivor_gc_alloc_region(); 78 inline OldGCAllocRegion* old_gc_alloc_region(); 79 80 // Allocation attempt during GC for a survivor object / PLAB. 81 HeapWord* survivor_attempt_allocation(size_t min_word_size, 82 size_t desired_word_size, 83 size_t* actual_word_size); 84 85 // Allocation attempt during GC for an old object / PLAB. 86 HeapWord* old_attempt_allocation(size_t min_word_size, 87 size_t desired_word_size, 88 size_t* actual_word_size); 89 90 // Node index of current thread. 91 inline uint current_node_index() const; 92 93 public: 94 G1Allocator(G1CollectedHeap* heap); 95 ~G1Allocator(); 96 97 #ifdef ASSERT 98 // Do we currently have an active mutator region to allocate into? 99 bool has_mutator_alloc_region(); 100 #endif 101 102 void init_mutator_alloc_regions(); 103 void release_mutator_alloc_regions(); 104 105 void init_gc_alloc_regions(G1EvacuationInfo& evacuation_info); 106 void release_gc_alloc_regions(G1EvacuationInfo& evacuation_info); 107 void abandon_gc_alloc_regions(); 108 bool is_retained_old_region(HeapRegion* hr); 109 110 // Allocate blocks of memory during mutator time. 111 112 inline HeapWord* attempt_allocation(size_t min_word_size, 113 size_t desired_word_size, 114 size_t* actual_word_size); 115 inline HeapWord* attempt_allocation_locked(size_t word_size); 116 inline HeapWord* attempt_allocation_force(size_t word_size); 117 118 size_t unsafe_max_tlab_alloc(); 119 size_t used_in_alloc_regions(); 120 121 // Allocate blocks of memory during garbage collection. Will ensure an 122 // allocation region, either by picking one or expanding the 123 // heap, and then allocate a block of the given size. The block 124 // may not be a humongous - it must fit into a single heap region. 125 HeapWord* par_allocate_during_gc(G1HeapRegionAttr dest, 126 size_t word_size); 127 128 HeapWord* par_allocate_during_gc(G1HeapRegionAttr dest, 129 size_t min_word_size, 130 size_t desired_word_size, 131 size_t* actual_word_size); 132 }; 133 134 // Manages the PLABs used during garbage collection. Interface for allocation from PLABs. 135 // Needs to handle multiple contexts, extra alignment in any "survivor" area and some 136 // statistics. 137 class G1PLABAllocator : public CHeapObj<mtGC> { 138 friend class G1ParScanThreadState; 139 private: 140 G1CollectedHeap* _g1h; 141 G1Allocator* _allocator; 142 143 PLAB _surviving_alloc_buffer; 144 PLAB _tenured_alloc_buffer; 145 PLAB* _alloc_buffers[G1HeapRegionAttr::Num]; 146 147 // The survivor alignment in effect in bytes. 148 // == 0 : don't align survivors 149 // != 0 : align survivors to that alignment 150 // These values were chosen to favor the non-alignment case since some 151 // architectures have a special compare against zero instructions. 152 const uint _survivor_alignment_bytes; 153 154 // Number of words allocated directly (not counting PLAB allocation). 155 size_t _direct_allocated[G1HeapRegionAttr::Num]; 156 157 void flush_and_retire_stats(); 158 inline PLAB* alloc_buffer(G1HeapRegionAttr dest); 159 160 // Calculate the survivor space object alignment in bytes. Returns that or 0 if 161 // there are no restrictions on survivor alignment. 162 static uint calc_survivor_alignment_bytes(); 163 164 bool may_throw_away_buffer(size_t const allocation_word_sz, size_t const buffer_size) const; 165 public: 166 G1PLABAllocator(G1Allocator* allocator); 167 168 size_t waste() const; 169 size_t undo_waste() const; 170 171 // Allocate word_sz words in dest, either directly into the regions or by 172 // allocating a new PLAB. Returns the address of the allocated memory, NULL if 173 // not successful. Plab_refill_failed indicates whether an attempt to refill the 174 // PLAB failed or not. 175 HeapWord* allocate_direct_or_new_plab(G1HeapRegionAttr dest, 176 size_t word_sz, 177 bool* plab_refill_failed); 178 179 // Allocate word_sz words in the PLAB of dest. Returns the address of the 180 // allocated memory, NULL if not successful. 181 inline HeapWord* plab_allocate(G1HeapRegionAttr dest, 182 size_t word_sz); 183 184 inline HeapWord* allocate(G1HeapRegionAttr dest, 185 size_t word_sz, 186 bool* refill_failed); 187 188 void undo_allocation(G1HeapRegionAttr dest, HeapWord* obj, size_t word_sz); 189 }; 190 191 // G1ArchiveRegionMap is a boolean array used to mark G1 regions as 192 // archive regions. This allows a quick check for whether an object 193 // should not be marked because it is in an archive region. 194 class G1ArchiveRegionMap : public G1BiasedMappedArray<bool> { 195 protected: 196 bool default_value() const { return false; } 197 }; 198 199 // G1ArchiveAllocator is used to allocate memory in archive 200 // regions. Such regions are not scavenged nor compacted by GC. 201 // There are two types of archive regions, which are 202 // differ in the kind of references allowed for the contained objects: 203 // 204 // - 'Closed' archive region contain no references outside of other 205 // closed archive regions. The region is immutable by GC. GC does 206 // not mark object header in 'closed' archive region. 207 // - An 'open' archive region allow references to any other regions, 208 // including closed archive, open archive and other java heap regions. 209 // GC can adjust pointers and mark object header in 'open' archive region. 210 class G1ArchiveAllocator : public CHeapObj<mtGC> { 211 protected: 212 bool _open; // Indicate if the region is 'open' archive. 213 G1CollectedHeap* _g1h; 214 215 // The current allocation region 216 HeapRegion* _allocation_region; 217 218 // Regions allocated for the current archive range. 219 GrowableArray<HeapRegion*> _allocated_regions; 220 221 // The number of bytes used in the current range. 222 size_t _summary_bytes_used; 223 224 // Current allocation window within the current region. 225 HeapWord* _bottom; 226 HeapWord* _top; 227 HeapWord* _max; 228 229 // Allocate a new region for this archive allocator. 230 // Allocation is from the top of the reserved heap downward. 231 bool alloc_new_region(); 232 233 public: 234 G1ArchiveAllocator(G1CollectedHeap* g1h, bool open) : 235 _open(open), 236 _g1h(g1h), 237 _allocation_region(NULL), 238 _allocated_regions((ResourceObj::set_allocation_type((address) &_allocated_regions, 239 ResourceObj::C_HEAP), 240 2), true /* C_Heap */), 241 _summary_bytes_used(0), 242 _bottom(NULL), 243 _top(NULL), 244 _max(NULL) { } 245 246 virtual ~G1ArchiveAllocator() { 247 assert(_allocation_region == NULL, "_allocation_region not NULL"); 248 } 249 250 static G1ArchiveAllocator* create_allocator(G1CollectedHeap* g1h, bool open); 251 252 // Allocate memory for an individual object. 253 HeapWord* archive_mem_allocate(size_t word_size); 254 255 // Return the memory ranges used in the current archive, after 256 // aligning to the requested alignment. 257 void complete_archive(GrowableArray<MemRegion>* ranges, 258 size_t end_alignment_in_bytes); 259 260 // The number of bytes allocated by this allocator. 261 size_t used() { 262 return _summary_bytes_used; 263 } 264 265 // Clear the count of bytes allocated in prior G1 regions. This 266 // must be done when recalculate_use is used to reset the counter 267 // for the generic allocator, since it counts bytes in all G1 268 // regions, including those still associated with this allocator. 269 void clear_used() { 270 _summary_bytes_used = 0; 271 } 272 273 // Create the _archive_region_map which is used to identify archive objects. 274 static inline void enable_archive_object_check(); 275 276 // Mark regions containing the specified address range as archive/non-archive. 277 static inline void set_range_archive(MemRegion range, bool open); 278 static inline void clear_range_archive(MemRegion range, bool open); 279 280 // Check if the object is in closed archive 281 static inline bool is_closed_archive_object(oop object); 282 // Check if the object is in open archive 283 static inline bool is_open_archive_object(oop object); 284 // Check if the object is either in closed archive or open archive 285 static inline bool is_archived_object(oop object); 286 287 private: 288 static bool _archive_check_enabled; 289 static G1ArchiveRegionMap _closed_archive_region_map; 290 static G1ArchiveRegionMap _open_archive_region_map; 291 292 // Check if an object is in a closed archive region using the _closed_archive_region_map. 293 static inline bool in_closed_archive_range(oop object); 294 // Check if an object is in open archive region using the _open_archive_region_map. 295 static inline bool in_open_archive_range(oop object); 296 297 // Check if archive object checking is enabled, to avoid calling in_open/closed_archive_range 298 // unnecessarily. 299 static inline bool archive_check_enabled(); 300 }; 301 302 #endif // SHARE_GC_G1_G1ALLOCATOR_HPP