1 /* 2 * Copyright (c) 2001, 2008, 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 class PSMarkSweepDecorator; 26 27 class PSYoungGen : public CHeapObj { 28 friend class VMStructs; 29 friend class ParallelScavengeHeap; 30 friend class AdjoiningGenerations; 31 32 protected: 33 MemRegion _reserved; 34 PSVirtualSpace* _virtual_space; 35 36 // Spaces 37 MutableSpace* _eden_space; 38 MutableSpace* _from_space; 39 MutableSpace* _to_space; 40 41 42 // MarkSweep Decorators 43 PSMarkSweepDecorator* _eden_mark_sweep; 44 PSMarkSweepDecorator* _from_mark_sweep; 45 PSMarkSweepDecorator* _to_mark_sweep; 46 47 // Sizing information, in bytes, set in constructor 48 const size_t _init_gen_size; 49 const size_t _min_gen_size; 50 const size_t _max_gen_size; 51 52 // Performance counters 53 PSGenerationCounters* _gen_counters; 54 SpaceCounters* _eden_counters; 55 SpaceCounters* _from_counters; 56 SpaceCounters* _to_counters; 57 58 // Initialize the space boundaries 59 void compute_initial_space_boundaries(); 60 61 // Space boundary helper 62 void set_space_boundaries(size_t eden_size, size_t survivor_size); 63 64 virtual bool resize_generation(size_t eden_size, size_t survivor_size); 65 virtual void resize_spaces(size_t eden_size, size_t survivor_size); 66 67 // Adjust the spaces to be consistent with the virtual space. 68 void post_resize(); 69 70 // Return number of bytes that the generation can change. 71 // These should not be used by PSYoungGen 72 virtual size_t available_for_expansion(); 73 virtual size_t available_for_contraction(); 74 75 // Given a desired shrinkage in the size of the young generation, 76 // return the actual size available for shrinkage. 77 virtual size_t limit_gen_shrink(size_t desired_change); 78 // returns the number of bytes available from the current size 79 // down to the minimum generation size. 80 size_t available_to_min_gen(); 81 // Return the number of bytes available for shrinkage considering 82 // the location the live data in the generation. 83 virtual size_t available_to_live(); 84 85 public: 86 // Initialize the generation. 87 PSYoungGen(size_t initial_byte_size, 88 size_t minimum_byte_size, 89 size_t maximum_byte_size); 90 void initialize_work(); 91 virtual void initialize(ReservedSpace rs, size_t alignment); 92 virtual void initialize_virtual_space(ReservedSpace rs, size_t alignment); 93 94 MemRegion reserved() const { return _reserved; } 95 96 bool is_in(const void* p) const { 97 return _virtual_space->contains((void *)p); 98 } 99 100 bool is_in_reserved(const void* p) const { 101 return reserved().contains((void *)p); 102 } 103 104 MutableSpace* eden_space() const { return _eden_space; } 105 MutableSpace* from_space() const { return _from_space; } 106 MutableSpace* to_space() const { return _to_space; } 107 PSVirtualSpace* virtual_space() const { return _virtual_space; } 108 109 // For Adaptive size policy 110 size_t min_gen_size() { return _min_gen_size; } 111 112 // MarkSweep support 113 PSMarkSweepDecorator* eden_mark_sweep() const { return _eden_mark_sweep; } 114 PSMarkSweepDecorator* from_mark_sweep() const { return _from_mark_sweep; } 115 PSMarkSweepDecorator* to_mark_sweep() const { return _to_mark_sweep; } 116 117 void precompact(); 118 void adjust_pointers(); 119 void compact(); 120 121 // Parallel Old 122 void move_and_update(ParCompactionManager* cm); 123 124 // Called during/after gc 125 void swap_spaces(); 126 127 // Resize generation using suggested free space size and survivor size 128 // NOTE: "eden_size" and "survivor_size" are suggestions only. Current 129 // heap layout (particularly, live objects in from space) might 130 // not allow us to use these values. 131 void resize(size_t eden_size, size_t survivor_size); 132 133 // Size info 134 size_t capacity_in_bytes() const; 135 size_t used_in_bytes() const; 136 size_t free_in_bytes() const; 137 138 size_t capacity_in_words() const; 139 size_t used_in_words() const; 140 size_t free_in_words() const; 141 142 // The max this generation can grow to 143 size_t max_size() const { return _reserved.byte_size(); } 144 145 // The max this generation can grow to if the boundary between 146 // the generations are allowed to move. 147 size_t gen_size_limit() const { return _max_gen_size; } 148 149 bool is_maximal_no_gc() const { 150 return true; // never expands except at a GC 151 } 152 153 // Allocation 154 HeapWord* allocate(size_t word_size, bool is_tlab) { 155 HeapWord* result = eden_space()->cas_allocate(word_size); 156 return result; 157 } 158 159 HeapWord** top_addr() const { return eden_space()->top_addr(); } 160 HeapWord** end_addr() const { return eden_space()->end_addr(); } 161 162 // Iteration. 163 void oop_iterate(OopClosure* cl); 164 void object_iterate(ObjectClosure* cl); 165 166 virtual void reset_after_change(); 167 virtual void reset_survivors_after_shrink(); 168 169 // Performance Counter support 170 void update_counters(); 171 172 // Debugging - do not use for time critical operations 173 void print() const; 174 void print_on(outputStream* st) const; 175 void print_used_change(size_t prev_used) const; 176 virtual const char* name() const { return "PSYoungGen"; } 177 178 void verify(bool allow_dirty); 179 180 // Space boundary invariant checker 181 void space_invariants() PRODUCT_RETURN; 182 183 // Helper for mangling survivor spaces. 184 void mangle_survivors(MutableSpace* s1, 185 MemRegion s1MR, 186 MutableSpace* s2, 187 MemRegion s2MR) PRODUCT_RETURN; 188 189 void record_spaces_top() PRODUCT_RETURN; 190 };