1 /* 2 * Copyright (c) 2014, 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_IMPLEMENTATION_G1_HEAPREGIONTYPE_HPP 26 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONTYPE_HPP 27 28 #include "memory/allocation.hpp" 29 30 #define hrt_assert_is_valid(tag) \ 31 assert(is_valid((tag)), err_msg("invalid HR type: %u", (uint) (tag))) 32 33 class HeapRegionType VALUE_OBJ_CLASS_SPEC { 34 private: 35 // We encode the value of the heap region type so the generation can be 36 // determined quickly. The tag is split into two parts: 37 // 38 // major type (young, humongous) : top N-1 bits 39 // minor type (eden / survivor, starts / cont hum, etc.) : bottom 1 bit 40 // 41 // If there's need to increase the number of minor types in the 42 // future, we'll have to increase the size of the latter and hence 43 // decrease the size of the former. 44 // 45 // 0000 0 [ 0] Free 46 // 47 // 0001 0 Young Mask 48 // 0001 0 [ 2] Eden 49 // 0001 1 [ 3] Survivor 50 // 51 // 0010 0 Humongous Mask 52 // 0010 0 [ 4] Starts Humongous 53 // 0010 1 [ 5] Continues Humongous 54 // 55 // 01000 [ 8] Old 56 typedef enum { 57 FreeTag = 0, 58 59 YoungMask = 2, 60 EdenTag = YoungMask, 61 SurvTag = YoungMask + 1, 62 63 HumongousMask = 4, 64 StartsHumongousTag = HumongousMask, 65 ContinuesHumongousTag = HumongousMask + 1, 66 67 OldTag = 8 68 } Tag; 69 70 volatile Tag _tag; 71 72 static bool is_valid(Tag tag); 73 74 Tag get() const { 75 hrt_assert_is_valid(_tag); 76 return _tag; 77 } 78 79 // Sets the type to 'tag'. 80 void set(Tag tag) { 81 hrt_assert_is_valid(tag); 82 hrt_assert_is_valid(_tag); 83 _tag = tag; 84 } 85 86 // Sets the type to 'tag', expecting the type to be 'before'. This 87 // is available for when we want to add sanity checking to the type 88 // transition. 89 void set_from(Tag tag, Tag before) { 90 hrt_assert_is_valid(tag); 91 hrt_assert_is_valid(before); 92 hrt_assert_is_valid(_tag); 93 assert(_tag == before, 94 err_msg("HR tag: %u, expected: %u new tag; %u", _tag, before, tag)); 95 _tag = tag; 96 } 97 98 public: 99 // Queries 100 101 bool is_free() const { return get() == FreeTag; } 102 103 bool is_young() const { return (get() & YoungMask) != 0; } 104 bool is_eden() const { return get() == EdenTag; } 105 bool is_survivor() const { return get() == SurvTag; } 106 107 bool is_humongous() const { return (get() & HumongousMask) != 0; } 108 bool is_starts_humongous() const { return get() == StartsHumongousTag; } 109 bool is_continues_humongous() const { return get() == ContinuesHumongousTag; } 110 111 bool is_old() const { return get() == OldTag; } 112 113 // Setters 114 115 void set_free() { set(FreeTag); } 116 117 void set_eden() { set_from(EdenTag, FreeTag); } 118 void set_eden_pre_gc() { set_from(EdenTag, SurvTag); } 119 void set_survivor() { set_from(SurvTag, FreeTag); } 120 121 void set_starts_humongous() { set_from(StartsHumongousTag, FreeTag); } 122 void set_continues_humongous() { set_from(ContinuesHumongousTag, FreeTag); } 123 124 void set_old() { set(OldTag); } 125 126 // Misc 127 128 const char* get_str() const; 129 const char* get_short_str() const; 130 131 HeapRegionType() : _tag(FreeTag) { hrt_assert_is_valid(_tag); } 132 }; 133 134 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONTYPE_HPP