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_PSYOUNGGEN_HPP 26 #define SHARE_GC_PARALLEL_PSYOUNGGEN_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 34 class PSYoungGen : public CHeapObj<mtGC> { 35 friend class VMStructs; 36 friend class ParallelScavengeHeap; 37 friend class AdjoiningGenerations; 38 39 protected: 40 MemRegion _reserved; 41 PSVirtualSpace* _virtual_space; 42 43 // Spaces 44 MutableSpace* _eden_space; 45 MutableSpace* _from_space; 46 MutableSpace* _to_space; 47 48 // Sizing information, in bytes, set in constructor 49 const size_t _init_gen_size; 50 const size_t _min_gen_size; 51 const size_t _max_gen_size; 52 53 // Performance counters 54 PSGenerationCounters* _gen_counters; 55 SpaceCounters* _eden_counters; 56 SpaceCounters* _from_counters; 57 SpaceCounters* _to_counters; 58 59 // Initialize the space boundaries 60 void compute_initial_space_boundaries(); 61 62 // Space boundary helper 63 void set_space_boundaries(size_t eden_size, size_t survivor_size); 64 65 virtual bool resize_generation(size_t eden_size, size_t survivor_size); 66 virtual void resize_spaces(size_t eden_size, size_t survivor_size); 67 68 // Adjust the spaces to be consistent with the virtual space. 69 void post_resize(); 70 71 // Return number of bytes that the generation can change. 72 // These should not be used by PSYoungGen 73 virtual size_t available_for_expansion(); 74 virtual size_t available_for_contraction(); 75 76 // Given a desired shrinkage in the size of the young generation, 77 // return the actual size available for shrinkage. 78 virtual size_t limit_gen_shrink(size_t desired_change); 79 // returns the number of bytes available from the current size 80 // down to the minimum generation size. 81 size_t available_to_min_gen(); 82 // Return the number of bytes available for shrinkage considering 83 // the location the live data in the generation. 84 virtual size_t available_to_live(); 85 86 public: 87 // Initialize the generation. 88 PSYoungGen(size_t initial_byte_size, 89 size_t minimum_byte_size, 90 size_t maximum_byte_size); 91 void initialize_work(); 92 virtual void initialize(ReservedSpace rs, size_t alignment); 93 virtual void initialize_virtual_space(ReservedSpace rs, size_t alignment); 94 95 MemRegion reserved() const { return _reserved; } 96 97 bool is_in(const void* p) const { 98 return _virtual_space->contains((void *)p); 99 } 100 101 bool is_in_reserved(const void* p) const { 102 return reserved().contains((void *)p); 103 } 104 105 MutableSpace* eden_space() const { return _eden_space; } 106 MutableSpace* from_space() const { return _from_space; } 107 MutableSpace* to_space() const { return _to_space; } 108 PSVirtualSpace* virtual_space() const { return _virtual_space; } 109 110 // For Adaptive size policy 111 size_t min_gen_size() { return _min_gen_size; } 112 113 // Called during/after GC 114 void swap_spaces(); 115 116 // Resize generation using suggested free space size and survivor size 117 // NOTE: "eden_size" and "survivor_size" are suggestions only. Current 118 // heap layout (particularly, live objects in from space) might 119 // not allow us to use these values. 120 void resize(size_t eden_size, size_t survivor_size); 121 122 // Size info 123 size_t capacity_in_bytes() const; 124 size_t used_in_bytes() const; 125 size_t free_in_bytes() const; 126 127 size_t capacity_in_words() const; 128 size_t used_in_words() const; 129 size_t free_in_words() const; 130 131 // The max this generation can grow to 132 size_t max_size() const { return _reserved.byte_size(); } 133 134 // The max this generation can grow to if the boundary between 135 // the generations are allowed to move. 136 size_t gen_size_limit() const { return _max_gen_size; } 137 138 bool is_maximal_no_gc() const { 139 return true; // Never expands except at a GC 140 } 141 142 // Allocation 143 HeapWord* allocate(size_t word_size) { 144 HeapWord* result = eden_space()->cas_allocate(word_size); 145 return result; 146 } 147 148 HeapWord* volatile* top_addr() const { return eden_space()->top_addr(); } 149 HeapWord** end_addr() const { return eden_space()->end_addr(); } 150 151 // Iteration. 152 void oop_iterate(OopIterateClosure* cl); 153 void object_iterate(ObjectClosure* cl); 154 155 virtual void reset_after_change(); 156 virtual void reset_survivors_after_shrink(); 157 158 // Performance Counter support 159 void update_counters(); 160 161 // Debugging - do not use for time critical operations 162 void print() const; 163 void print_on(outputStream* st) const; 164 virtual const char* name() const { return "PSYoungGen"; } 165 166 void verify(); 167 168 // Space boundary invariant checker 169 void space_invariants() PRODUCT_RETURN; 170 171 // Helper for mangling survivor spaces. 172 void mangle_survivors(MutableSpace* s1, 173 MemRegion s1MR, 174 MutableSpace* s2, 175 MemRegion s2MR) PRODUCT_RETURN; 176 177 void record_spaces_top() PRODUCT_RETURN; 178 }; 179 180 #endif // SHARE_GC_PARALLEL_PSYOUNGGEN_HPP