1 /* 2 * Copyright (c) 2001, 2013, 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_MEMORY_TENUREDGENERATION_HPP 26 #define SHARE_VM_MEMORY_TENUREDGENERATION_HPP 27 28 #include "gc_implementation/shared/cSpaceCounters.hpp" 29 #include "gc_implementation/shared/gcStats.hpp" 30 #include "gc_implementation/shared/generationCounters.hpp" 31 #include "memory/generation.hpp" 32 #include "utilities/macros.hpp" 33 34 // TenuredGeneration models the heap containing old (promoted/tenured) objects 35 // contained in a single contiguous space. 36 // 37 // Garbage collection is performed using mark-compact. 38 39 class TenuredGeneration: public CardGeneration { 40 friend class VMStructs; 41 // Abstractly, this is a subtype that gets access to protected fields. 42 friend class VM_PopulateDumpSharedSpace; 43 44 protected: 45 ContiguousSpace* _the_space; // actual space holding objects 46 WaterMark _last_gc; // watermark between objects allocated before 47 // and after last GC. 48 49 GenerationCounters* _gen_counters; 50 CSpaceCounters* _space_counters; 51 52 // Grow generation with specified size (returns false if unable to grow) 53 virtual bool grow_by(size_t bytes); 54 // Grow generation to reserved size. 55 virtual bool grow_to_reserved(); 56 // Shrink generation with specified size (returns false if unable to shrink) 57 void shrink_by(size_t bytes); 58 59 // Allocation failure 60 virtual bool expand(size_t bytes, size_t expand_bytes); 61 void shrink(size_t bytes); 62 63 // Accessing spaces 64 ContiguousSpace* the_space() const { return _the_space; } 65 66 public: 67 TenuredGeneration(ReservedSpace rs, size_t initial_byte_size, 68 int level, GenRemSet* remset); 69 70 Generation::Name kind() { return Generation::MarkSweepCompact; } 71 72 // Printing 73 const char* name() const { return "tenured generation"; } 74 const char* short_name() const { return "Tenured"; } 75 76 // Does a "full" (forced) collection invoked on this generation collect 77 // all younger generations as well? Note that this is a 78 // hack to allow the collection of the younger gen first if the flag is 79 // set. 80 virtual bool full_collects_younger_generations() const { 81 return !ScavengeBeforeFullGC; 82 } 83 84 inline bool is_in(const void* p) const; 85 86 // Space enquiries 87 size_t capacity() const; 88 size_t used() const; 89 size_t free() const; 90 91 MemRegion used_region() const; 92 93 size_t unsafe_max_alloc_nogc() const; 94 size_t contiguous_available() const; 95 96 // Iteration 97 void object_iterate(ObjectClosure* blk); 98 void space_iterate(SpaceClosure* blk, bool usedOnly = false); 99 100 void younger_refs_iterate(OopsInGenClosure* blk); 101 102 inline CompactibleSpace* first_compaction_space() const; 103 104 virtual inline HeapWord* allocate(size_t word_size, bool is_tlab); 105 virtual inline HeapWord* par_allocate(size_t word_size, bool is_tlab); 106 107 // Accessing marks 108 inline WaterMark top_mark(); 109 inline WaterMark bottom_mark(); 110 111 #define TenuredGen_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \ 112 void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl); 113 TenuredGen_SINCE_SAVE_MARKS_DECL(OopsInGenClosure,_v) 114 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(TenuredGen_SINCE_SAVE_MARKS_DECL) 115 116 void save_marks(); 117 void reset_saved_marks(); 118 bool no_allocs_since_save_marks(); 119 120 inline size_t block_size(const HeapWord* addr) const; 121 122 inline bool block_is_obj(const HeapWord* addr) const; 123 124 virtual void collect(bool full, 125 bool clear_all_soft_refs, 126 size_t size, 127 bool is_tlab); 128 HeapWord* expand_and_allocate(size_t size, 129 bool is_tlab, 130 bool parallel = false); 131 132 virtual void prepare_for_verify(); 133 134 135 virtual void gc_prologue(bool full); 136 virtual void gc_epilogue(bool full); 137 bool should_collect(bool full, 138 size_t word_size, 139 bool is_tlab); 140 141 virtual void compute_new_size(); 142 143 // Performance Counter support 144 void update_counters(); 145 146 virtual void record_spaces_top(); 147 148 // Statistics 149 150 virtual void update_gc_stats(int level, bool full); 151 152 virtual bool promotion_attempt_is_safe(size_t max_promoted_in_bytes) const; 153 154 virtual void verify(); 155 virtual void print_on(outputStream* st) const; 156 }; 157 158 #endif // SHARE_VM_MEMORY_TENUREDGENERATION_HPP