1 /* 2 * Copyright (c) 2001, 2020, 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_PARALLEL_PSOLDGEN_HPP 26 #define SHARE_GC_PARALLEL_PSOLDGEN_HPP 27 28 #include "gc/parallel/mutableSpace.hpp" 29 #include "gc/parallel/objectStartArray.hpp" 30 #include "gc/parallel/psGenerationCounters.hpp" 31 #include "gc/parallel/psVirtualspace.hpp" 32 #include "gc/parallel/spaceCounters.hpp" 33 #include "runtime/safepoint.hpp" 34 35 class PSOldGen : public CHeapObj<mtGC> { 36 friend class VMStructs; 37 friend class PSPromotionManager; // Uses the cas_allocate methods 38 friend class ParallelScavengeHeap; 39 friend class AdjoiningGenerations; 40 41 private: 42 MemRegion _reserved; // Used for simple containment tests 43 PSVirtualSpace* _virtual_space; // Controls mapping and unmapping of virtual mem 44 ObjectStartArray _start_array; // Keeps track of where objects start in a 512b block 45 MutableSpace* _object_space; // Where all the objects live 46 47 // Performance Counters 48 PSGenerationCounters* _gen_counters; 49 SpaceCounters* _space_counters; 50 51 // Sizing information, in bytes, set in constructor 52 const size_t _init_gen_size; 53 const size_t _min_gen_size; 54 const size_t _max_gen_size; 55 56 #ifdef ASSERT 57 void assert_block_in_covered_region(MemRegion new_memregion) { 58 // Explictly capture current covered_region in a local 59 MemRegion covered_region = this->start_array()->covered_region(); 60 assert(covered_region.contains(new_memregion), 61 "new region is not in covered_region [ " PTR_FORMAT ", " PTR_FORMAT " ], " 62 "new region [ " PTR_FORMAT ", " PTR_FORMAT " ], " 63 "object space [ " PTR_FORMAT ", " PTR_FORMAT " ]", 64 p2i(covered_region.start()), 65 p2i(covered_region.end()), 66 p2i(new_memregion.start()), 67 p2i(new_memregion.end()), 68 p2i(this->object_space()->used_region().start()), 69 p2i(this->object_space()->used_region().end())); 70 } 71 #endif 72 73 HeapWord* allocate_noexpand(size_t word_size) { 74 // We assume the heap lock is held here. 75 assert_locked_or_safepoint(Heap_lock); 76 HeapWord* res = object_space()->allocate(word_size); 77 if (res != NULL) { 78 DEBUG_ONLY(assert_block_in_covered_region(MemRegion(res, word_size))); 79 _start_array.allocate_block(res); 80 } 81 return res; 82 } 83 84 // Support for MT garbage collection. CAS allocation is lower overhead than grabbing 85 // and releasing the heap lock, which is held during gc's anyway. This method is not 86 // safe for use at the same time as allocate_noexpand()! 87 HeapWord* cas_allocate_noexpand(size_t word_size) { 88 assert(SafepointSynchronize::is_at_safepoint(), "Must only be called at safepoint"); 89 HeapWord* res = object_space()->cas_allocate(word_size); 90 if (res != NULL) { 91 DEBUG_ONLY(assert_block_in_covered_region(MemRegion(res, word_size))); 92 _start_array.allocate_block(res); 93 } 94 return res; 95 } 96 97 // Support for MT garbage collection. See above comment. 98 HeapWord* cas_allocate(size_t word_size) { 99 HeapWord* res = cas_allocate_noexpand(word_size); 100 return (res == NULL) ? expand_and_cas_allocate(word_size) : res; 101 } 102 103 HeapWord* expand_and_allocate(size_t word_size); 104 HeapWord* expand_and_cas_allocate(size_t word_size); 105 void expand(size_t bytes); 106 bool expand_by(size_t bytes); 107 bool expand_to_reserved(); 108 109 void shrink(size_t bytes); 110 111 void post_resize(); 112 113 void initialize(ReservedSpace rs, size_t alignment, 114 const char* perf_data_name, int level); 115 void initialize_virtual_space(ReservedSpace rs, size_t alignment); 116 void initialize_work(const char* perf_data_name, int level); 117 void initialize_performance_counters(const char* perf_data_name, int level); 118 119 public: 120 // Initialize the generation. 121 PSOldGen(ReservedSpace rs, size_t initial_size, size_t min_size, 122 size_t max_size, const char* perf_data_name, int level); 123 124 MemRegion reserved() const { return _reserved; } 125 virtual size_t max_gen_size() { return _max_gen_size; } 126 size_t min_gen_size() { return _min_gen_size; } 127 128 // Returns limit on the maximum size of the generation. This 129 // is the same as _max_gen_size for PSOldGen but need not be 130 // for a derived class. 131 virtual size_t gen_size_limit(); 132 133 bool is_in(const void* p) const { 134 return _virtual_space->contains((void *)p); 135 } 136 137 bool is_in_reserved(const void* p) const { 138 return reserved().contains(p); 139 } 140 141 MutableSpace* object_space() const { return _object_space; } 142 ObjectStartArray* start_array() { return &_start_array; } 143 PSVirtualSpace* virtual_space() const { return _virtual_space;} 144 145 // Has the generation been successfully allocated? 146 bool is_allocated(); 147 148 // Size info 149 size_t capacity_in_bytes() const { return object_space()->capacity_in_bytes(); } 150 size_t used_in_bytes() const { return object_space()->used_in_bytes(); } 151 size_t free_in_bytes() const { return object_space()->free_in_bytes(); } 152 153 size_t capacity_in_words() const { return object_space()->capacity_in_words(); } 154 size_t used_in_words() const { return object_space()->used_in_words(); } 155 size_t free_in_words() const { return object_space()->free_in_words(); } 156 157 bool is_maximal_no_gc() const { 158 return virtual_space()->uncommitted_size() == 0; 159 } 160 161 // Calculating new sizes 162 void resize(size_t desired_free_space); 163 164 // Allocation. We report all successful allocations to the size policy 165 // Note that the perm gen does not use this method, and should not! 166 HeapWord* allocate(size_t word_size); 167 168 // Iteration. 169 void oop_iterate(OopIterateClosure* cl) { object_space()->oop_iterate(cl); } 170 void object_iterate(ObjectClosure* cl) { object_space()->object_iterate(cl); } 171 172 // Debugging - do not use for time critical operations 173 void print() const; 174 virtual void print_on(outputStream* st) const; 175 176 void verify(); 177 void verify_object_start_array(); 178 179 // Performance Counter support 180 void update_counters(); 181 182 // Printing support 183 const char* name() const { return "ParOldGen"; } 184 185 // Debugging support 186 // Save the tops of all spaces for later use during mangling. 187 void record_spaces_top() PRODUCT_RETURN; 188 }; 189 190 #endif // SHARE_GC_PARALLEL_PSOLDGEN_HPP