1 /* 2 * Copyright 2001-2008 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, 20 * CA 95054 USA or visit www.sun.com if you need additional information or 21 * have any questions. 22 * 23 */ 24 25 class PSMarkSweepDecorator; 26 27 class PSOldGen : public CHeapObj { 28 friend class VMStructs; 29 friend class PSPromotionManager; // Uses the cas_allocate methods 30 friend class ParallelScavengeHeap; 31 friend class AdjoiningGenerations; 32 33 protected: 34 MemRegion _reserved; // Used for simple containment tests 35 PSVirtualSpace* _virtual_space; // Controls mapping and unmapping of virtual mem 36 ObjectStartArray _start_array; // Keeps track of where objects start in a 512b block 37 MutableSpace* _object_space; // Where all the objects live 38 PSMarkSweepDecorator* _object_mark_sweep; // The mark sweep view of _object_space 39 const char* const _name; // Name of this generation. 40 41 // Performance Counters 42 PSGenerationCounters* _gen_counters; 43 SpaceCounters* _space_counters; 44 45 // Sizing information, in bytes, set in constructor 46 const size_t _init_gen_size; 47 const size_t _min_gen_size; 48 const size_t _max_gen_size; 49 50 // Used when initializing the _name field. 51 static inline const char* select_name(); 52 53 HeapWord* allocate_noexpand(size_t word_size, bool is_tlab) { 54 // We assume the heap lock is held here. 55 assert(!is_tlab, "Does not support TLAB allocation"); 56 assert_locked_or_safepoint(Heap_lock); 57 HeapWord* res = object_space()->allocate(word_size); 58 if (res != NULL) { 59 _start_array.allocate_block(res); 60 } 61 return res; 62 } 63 64 // Support for MT garbage collection. CAS allocation is lower overhead than grabbing 65 // and releasing the heap lock, which is held during gc's anyway. This method is not 66 // safe for use at the same time as allocate_noexpand()! 67 HeapWord* cas_allocate_noexpand(size_t word_size) { 68 assert(SafepointSynchronize::is_at_safepoint(), "Must only be called at safepoint") 69 HeapWord* res = object_space()->cas_allocate(word_size); 70 if (res != NULL) { 71 _start_array.allocate_block(res); 72 } 73 return res; 74 } 75 76 // Support for MT garbage collection. See above comment. 77 HeapWord* cas_allocate(size_t word_size) { 78 HeapWord* res = cas_allocate_noexpand(word_size); 79 return (res == NULL) ? expand_and_cas_allocate(word_size) : res; 80 } 81 82 HeapWord* expand_and_allocate(size_t word_size, bool is_tlab); 83 HeapWord* expand_and_cas_allocate(size_t word_size); 84 void expand(size_t bytes); 85 bool expand_by(size_t bytes); 86 bool expand_to_reserved(); 87 88 void shrink(size_t bytes); 89 90 void post_resize(); 91 92 public: 93 // Initialize the generation. 94 PSOldGen(ReservedSpace rs, size_t alignment, 95 size_t initial_size, size_t min_size, size_t max_size, 96 const char* perf_data_name, int level); 97 98 PSOldGen(size_t initial_size, size_t min_size, size_t max_size, 99 const char* perf_data_name, int level); 100 101 void initialize(ReservedSpace rs, size_t alignment, 102 const char* perf_data_name, int level); 103 void initialize_virtual_space(ReservedSpace rs, size_t alignment); 104 void initialize_work(const char* perf_data_name, int level); 105 106 MemRegion reserved() const { return _reserved; } 107 virtual size_t max_gen_size() { return _max_gen_size; } 108 size_t min_gen_size() { return _min_gen_size; } 109 size_t init_gen_size() { return _init_gen_size; } 110 111 // Returns limit on the maximum size of the generation. This 112 // is the same as _max_gen_size for PSOldGen but need not be 113 // for a derived class. 114 virtual size_t gen_size_limit(); 115 116 bool is_in(const void* p) const { 117 return _virtual_space->contains((void *)p); 118 } 119 120 bool is_in_reserved(const void* p) const { 121 return reserved().contains(p); 122 } 123 124 MutableSpace* object_space() const { return _object_space; } 125 PSMarkSweepDecorator* object_mark_sweep() const { return _object_mark_sweep; } 126 ObjectStartArray* start_array() { return &_start_array; } 127 PSVirtualSpace* virtual_space() const { return _virtual_space;} 128 129 // Has the generation been successfully allocated? 130 bool is_allocated(); 131 132 // MarkSweep methods 133 virtual void precompact(); 134 void adjust_pointers(); 135 void compact(); 136 137 // Parallel old 138 virtual void move_and_update(ParCompactionManager* cm); 139 140 // Size info 141 size_t capacity_in_bytes() const { return object_space()->capacity_in_bytes(); } 142 size_t used_in_bytes() const { return object_space()->used_in_bytes(); } 143 size_t free_in_bytes() const { return object_space()->free_in_bytes(); } 144 145 size_t capacity_in_words() const { return object_space()->capacity_in_words(); } 146 size_t used_in_words() const { return object_space()->used_in_words(); } 147 size_t free_in_words() const { return object_space()->free_in_words(); } 148 149 // Includes uncommitted memory 150 size_t contiguous_available() const; 151 152 bool is_maximal_no_gc() const { 153 return virtual_space()->uncommitted_size() == 0; 154 } 155 156 // Calculating new sizes 157 void resize(size_t desired_free_space); 158 159 // Allocation. We report all successful allocations to the size policy 160 // Note that the perm gen does not use this method, and should not! 161 HeapWord* allocate(size_t word_size, bool is_tlab); 162 163 // Iteration. 164 void oop_iterate(OopClosure* cl) { object_space()->oop_iterate(cl); } 165 void object_iterate(ObjectClosure* cl) { object_space()->object_iterate(cl); } 166 167 // Debugging - do not use for time critical operations 168 virtual void print() const; 169 virtual void print_on(outputStream* st) const; 170 void print_used_change(size_t prev_used) const; 171 172 void verify(bool allow_dirty); 173 void verify_object_start_array(); 174 175 // These should not used 176 virtual void reset_after_change(); 177 178 // These should not used 179 virtual size_t available_for_expansion(); 180 virtual size_t available_for_contraction(); 181 182 void space_invariants() PRODUCT_RETURN; 183 184 // Performace Counter support 185 void update_counters(); 186 187 // Printing support 188 virtual const char* name() const { return _name; } 189 190 // Debugging support 191 // Save the tops of all spaces for later use during mangling. 192 void record_spaces_top() PRODUCT_RETURN; 193 194 void try_to_shrink_by(size_t shrink_bytes); 195 };