1 /* 2 * Copyright (c) 2014, 2017, 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_G1_HEAPREGIONTYPE_HPP 26 #define SHARE_VM_GC_G1_HEAPREGIONTYPE_HPP 27 28 #include "gc/g1/g1HeapRegionTraceType.hpp" 29 #include "memory/allocation.hpp" 30 31 #define hrt_assert_is_valid(tag) \ 32 assert(is_valid((tag)), "invalid HR type: %u", (uint) (tag)) 33 34 class HeapRegionType VALUE_OBJ_CLASS_SPEC { 35 private: 36 // We encode the value of the heap region type so the generation can be 37 // determined quickly. The tag is split into two parts: 38 // 39 // major type (young, old, humongous, archive) : top N-1 bits 40 // minor type (eden / survivor, starts / cont hum, etc.) : bottom 1 bit 41 // 42 // If there's need to increase the number of minor types in the 43 // future, we'll have to increase the size of the latter and hence 44 // decrease the size of the former. 45 // 46 // 00000 0 [ 0] Free 47 // 48 // 00001 0 [ 2] Young Mask 49 // 00001 0 [ 2] Eden 50 // 00001 1 [ 3] Survivor 51 // 52 // 00010 0 [ 4] Humongous Mask 53 // 00100 0 [ 8] Pinned Mask 54 // 00110 0 [12] Starts Humongous 55 // 00110 1 [13] Continues Humongous 56 // 57 // 01000 0 [16] Old Mask 58 // 59 // 10000 0 [32] Archive Mask 60 // 11100 0 [56] Open Archive 61 // 11100 1 [57] Closed Archive 62 // 63 typedef enum { 64 FreeTag = 0, 65 66 YoungMask = 2, 67 EdenTag = YoungMask, 68 SurvTag = YoungMask + 1, 69 70 HumongousMask = 4, 71 PinnedMask = 8, 72 StartsHumongousTag = HumongousMask | PinnedMask, 73 ContinuesHumongousTag = HumongousMask | PinnedMask + 1, 74 75 OldMask = 16, 76 OldTag = OldMask, 77 78 // Archive regions are regions with immutable content (i.e. not reclaimed, and 79 // not allocated into during regular operation). They differ in the kind of references 80 // allowed for the contained objects: 81 // - Closed archive regions form a separate self-contained (closed) object graph 82 // within the set of all of these regions. No references outside of closed 83 // archive regions are allowed. 84 // - Open archive regions have no restrictions on the references of their objects. 85 // Objects within these regions are allowed to have references to objects 86 // contained in any other kind of regions. 87 ArchiveMask = 32, 88 OpenArchiveTag = ArchiveMask | PinnedMask | OldMask, 89 ClosedArchiveTag = ArchiveMask | PinnedMask | OldMask + 1 90 } Tag; 91 92 volatile Tag _tag; 93 94 static bool is_valid(Tag tag); 95 96 Tag get() const { 97 hrt_assert_is_valid(_tag); 98 return _tag; 99 } 100 101 // Sets the type to 'tag'. 102 void set(Tag tag) { 103 hrt_assert_is_valid(tag); 104 hrt_assert_is_valid(_tag); 105 _tag = tag; 106 } 107 108 // Sets the type to 'tag', expecting the type to be 'before'. This 109 // is available for when we want to add sanity checking to the type 110 // transition. 111 void set_from(Tag tag, Tag before) { 112 hrt_assert_is_valid(tag); 113 hrt_assert_is_valid(before); 114 hrt_assert_is_valid(_tag); 115 assert(_tag == before, "HR tag: %u, expected: %u new tag; %u", _tag, before, tag); 116 _tag = tag; 117 } 118 119 public: 120 // Queries 121 122 bool is_free() const { return get() == FreeTag; } 123 124 bool is_young() const { return (get() & YoungMask) != 0; } 125 bool is_eden() const { return get() == EdenTag; } 126 bool is_survivor() const { return get() == SurvTag; } 127 128 bool is_humongous() const { return (get() & HumongousMask) != 0; } 129 bool is_starts_humongous() const { return get() == StartsHumongousTag; } 130 bool is_continues_humongous() const { return get() == ContinuesHumongousTag; } 131 132 bool is_archive() const { return (get() & ArchiveMask) != 0; } 133 bool is_open_archive() const { return get() == OpenArchiveTag; } 134 bool is_closed_archive() const { return get() == ClosedArchiveTag; } 135 136 // is_old regions may or may not also be pinned 137 bool is_old() const { return (get() & OldMask) != 0; } 138 139 bool is_old_or_humongous() const { return (get() & (OldMask | HumongousMask)) != 0; } 140 141 // is_pinned regions may be archive or humongous 142 bool is_pinned() const { return (get() & PinnedMask) != 0; } 143 144 // Setters 145 146 void set_free() { set(FreeTag); } 147 148 void set_eden() { set_from(EdenTag, FreeTag); } 149 void set_eden_pre_gc() { set_from(EdenTag, SurvTag); } 150 void set_survivor() { set_from(SurvTag, FreeTag); } 151 152 void set_starts_humongous() { set_from(StartsHumongousTag, FreeTag); } 153 void set_continues_humongous() { set_from(ContinuesHumongousTag, FreeTag); } 154 155 void set_old() { set(OldTag); } 156 157 // Change the current region type to be of an old region type if not already done so. 158 // Returns whether the region type has been changed or not. 159 bool relabel_as_old() { 160 //assert(!is_free(), "Should not try to move Free region"); 161 assert(!is_humongous(), "Should not try to move Humongous region"); 162 if (is_old()) { 163 return false; 164 } 165 if (is_eden()) { 166 set_from(OldTag, EdenTag); 167 return true; 168 } else if (is_free()) { 169 set_from(OldTag, FreeTag); 170 return true; 171 } else { 172 set_from(OldTag, SurvTag); 173 return true; 174 } 175 } 176 void set_open_archive() { set_from(OpenArchiveTag, FreeTag); } 177 void set_closed_archive() { set_from(ClosedArchiveTag, FreeTag); } 178 179 // Misc 180 181 const char* get_str() const; 182 const char* get_short_str() const; 183 G1HeapRegionTraceType::Type get_trace_type(); 184 185 HeapRegionType() : _tag(FreeTag) { hrt_assert_is_valid(_tag); } 186 }; 187 188 #endif // SHARE_VM_GC_G1_HEAPREGIONTYPE_HPP