1 /* 2 * Copyright (c) 2001, 2010, 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 33 // TenuredGeneration models the heap containing old (promoted/tenured) objects. 34 35 class ParGCAllocBufferWithBOT; 36 37 class TenuredGeneration: public OneContigSpaceCardGeneration { 38 friend class VMStructs; 39 protected: 40 // current shrinking effect: this damps shrinking when the heap gets empty. 41 size_t _shrink_factor; 42 // Some statistics from before gc started. 43 // These are gathered in the gc_prologue (and should_collect) 44 // to control growing/shrinking policy in spite of promotions. 45 size_t _capacity_at_prologue; 46 size_t _used_at_prologue; 47 48 #ifndef SERIALGC 49 // To support parallel promotion: an array of parallel allocation 50 // buffers, one per thread, initially NULL. 51 ParGCAllocBufferWithBOT** _alloc_buffers; 52 #endif // SERIALGC 53 54 // Retire all alloc buffers before a full GC, so that they will be 55 // re-allocated at the start of the next young GC. 56 void retire_alloc_buffers_before_full_gc(); 57 58 GenerationCounters* _gen_counters; 59 CSpaceCounters* _space_counters; 60 61 public: 62 TenuredGeneration(ReservedSpace rs, size_t initial_byte_size, int level, 63 GenRemSet* remset); 64 65 Generation::Name kind() { return Generation::MarkSweepCompact; } 66 67 // Printing 68 const char* name() const; 69 const char* short_name() const { return "Tenured"; } 70 bool must_be_youngest() const { return false; } 71 bool must_be_oldest() const { return true; } 72 73 // Does a "full" (forced) collection invoked on this generation collect 74 // all younger generations as well? Note that this is a 75 // hack to allow the collection of the younger gen first if the flag is 76 // set. This is better than using th policy's should_collect_gen0_first() 77 // since that causes us to do an extra unnecessary pair of restart-&-stop-world. 78 virtual bool full_collects_younger_generations() const { 79 return !CollectGen0First; 80 } 81 82 // Mark sweep support 83 void compute_new_size(); 84 85 virtual void gc_prologue(bool full); 86 virtual void gc_epilogue(bool full); 87 bool should_collect(bool full, 88 size_t word_size, 89 bool is_tlab); 90 91 virtual void collect(bool full, 92 bool clear_all_soft_refs, 93 size_t size, 94 bool is_tlab); 95 96 #ifndef SERIALGC 97 // Overrides. 98 virtual oop par_promote(int thread_num, 99 oop obj, markOop m, size_t word_sz); 100 virtual void par_promote_alloc_undo(int thread_num, 101 HeapWord* obj, size_t word_sz); 102 virtual void par_promote_alloc_done(int thread_num); 103 #endif // SERIALGC 104 105 // Performance Counter support 106 void update_counters(); 107 108 // Statistics 109 110 virtual void update_gc_stats(int level, bool full); 111 112 virtual bool promotion_attempt_is_safe(size_t max_promoted_in_bytes, 113 bool younger_handles_promotion_failure) const; 114 115 void verify_alloc_buffers_clean(); 116 }; 117 118 #endif // SHARE_VM_MEMORY_TENUREDGENERATION_HPP