1 /* 2 * Copyright (c) 2001, 2016, 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_PARALLEL_PSYOUNGGEN_HPP 26 #define SHARE_VM_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 PSMarkSweepDecorator; 35 36 class PSYoungGen : public CHeapObj<mtGC> { 37 friend class VMStructs; 38 friend class ParallelScavengeHeap; 39 friend class AdjoiningGenerations; 40 41 protected: 42 MemRegion _reserved; 43 PSVirtualSpace* _virtual_space; 44 45 // Spaces 46 MutableSpace* _eden_space; 47 MutableSpace* _from_space; 48 MutableSpace* _to_space; 49 50 51 // MarkSweep Decorators 52 PSMarkSweepDecorator* _eden_mark_sweep; 53 PSMarkSweepDecorator* _from_mark_sweep; 54 PSMarkSweepDecorator* _to_mark_sweep; 55 56 // Sizing information, in bytes, set in constructor 57 const size_t _init_gen_size; 58 const size_t _min_gen_size; 59 const size_t _max_gen_size; 60 61 // Performance counters 62 PSGenerationCounters* _gen_counters; 63 SpaceCounters* _eden_counters; 64 SpaceCounters* _from_counters; 65 SpaceCounters* _to_counters; 66 67 // Initialize the space boundaries 68 void compute_initial_space_boundaries(); 69 70 // Space boundary helper 71 void set_space_boundaries(size_t eden_size, size_t survivor_size); 72 73 virtual bool resize_generation(size_t eden_size, size_t survivor_size); 74 virtual void resize_spaces(size_t eden_size, size_t survivor_size); 75 76 // Adjust the spaces to be consistent with the virtual space. 77 void post_resize(); 78 79 // Return number of bytes that the generation can change. 80 // These should not be used by PSYoungGen 81 virtual size_t available_for_expansion(); 82 virtual size_t available_for_contraction(); 83 84 // Given a desired shrinkage in the size of the young generation, 85 // return the actual size available for shrinkage. 86 virtual size_t limit_gen_shrink(size_t desired_change); 87 // returns the number of bytes available from the current size 88 // down to the minimum generation size. 89 size_t available_to_min_gen(); 90 // Return the number of bytes available for shrinkage considering 91 // the location the live data in the generation. 92 virtual size_t available_to_live(); 93 94 public: 95 // Initialize the generation. 96 PSYoungGen(size_t initial_byte_size, 97 size_t minimum_byte_size, 98 size_t maximum_byte_size); 99 void initialize_work(); 100 virtual void initialize(ReservedSpace rs, size_t alignment); 101 virtual void initialize_virtual_space(ReservedSpace rs, size_t alignment); 102 103 MemRegion reserved() const { return _reserved; } 104 105 bool is_in(const void* p) const { 106 return _virtual_space->contains((void *)p); 107 } 108 109 bool is_in_reserved(const void* p) const { 110 return reserved().contains((void *)p); 111 } 112 113 MutableSpace* eden_space() const { return _eden_space; } 114 MutableSpace* from_space() const { return _from_space; } 115 MutableSpace* to_space() const { return _to_space; } 116 PSVirtualSpace* virtual_space() const { return _virtual_space; } 117 118 // For Adaptive size policy 119 size_t min_gen_size() { return _min_gen_size; } 120 121 // MarkSweep support 122 PSMarkSweepDecorator* eden_mark_sweep() const { return _eden_mark_sweep; } 123 PSMarkSweepDecorator* from_mark_sweep() const { return _from_mark_sweep; } 124 PSMarkSweepDecorator* to_mark_sweep() const { return _to_mark_sweep; } 125 126 void precompact(); 127 void adjust_pointers(); 128 void compact(); 129 130 // Called during/after GC 131 void swap_spaces(); 132 133 // Resize generation using suggested free space size and survivor size 134 // NOTE: "eden_size" and "survivor_size" are suggestions only. Current 135 // heap layout (particularly, live objects in from space) might 136 // not allow us to use these values. 137 void resize(size_t eden_size, size_t survivor_size); 138 139 // Size info 140 size_t capacity_in_bytes() const; 141 size_t used_in_bytes() const; 142 size_t free_in_bytes() const; 143 144 size_t capacity_in_words() const; 145 size_t used_in_words() const; 146 size_t free_in_words() const; 147 148 // The max this generation can grow to 149 size_t max_size() const { return _reserved.byte_size(); } 150 151 // The max this generation can grow to if the boundary between 152 // the generations are allowed to move. 153 size_t gen_size_limit() const { return _max_gen_size; } 154 155 bool is_maximal_no_gc() const { 156 return true; // Never expands except at a GC 157 } 158 159 // Allocation 160 HeapWord* allocate(size_t word_size) { 161 HeapWord* result = eden_space()->cas_allocate(word_size); 162 return result; 163 } 164 165 HeapWord* volatile* top_addr() const { return eden_space()->top_addr(); } 166 HeapWord** end_addr() const { return eden_space()->end_addr(); } 167 168 // Iteration. 169 void oop_iterate(ExtendedOopClosure* cl); 170 void object_iterate(ObjectClosure* cl); 171 172 virtual void reset_after_change(); 173 virtual void reset_survivors_after_shrink(); 174 175 // Performance Counter support 176 void update_counters(); 177 178 // Debugging - do not use for time critical operations 179 void print() const; 180 void print_on(outputStream* st) const; 181 void print_used_change(size_t prev_used) const; 182 virtual const char* name() const { return "PSYoungGen"; } 183 184 void verify(); 185 186 // Space boundary invariant checker 187 void space_invariants() PRODUCT_RETURN; 188 189 // Helper for mangling survivor spaces. 190 void mangle_survivors(MutableSpace* s1, 191 MemRegion s1MR, 192 MutableSpace* s2, 193 MemRegion s2MR) PRODUCT_RETURN; 194 195 void record_spaces_top() PRODUCT_RETURN; 196 }; 197 198 #endif // SHARE_VM_GC_PARALLEL_PSYOUNGGEN_HPP