1 /* 2 * Copyright (c) 2014, 2018, 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 30 #define hrt_assert_is_valid(tag) \ 31 assert(is_valid((tag)), "invalid HR type: %u", (uint) (tag)) 32 33 class HeapRegionType { 34 friend class VMStructs; 35 36 private: 37 // We encode the value of the heap region type so the generation can be 38 // determined quickly. The tag is split into two parts: 39 // 40 // major type (young, old, humongous, archive) : top N-1 bits 41 // minor type (eden / survivor, starts / cont hum, etc.) : bottom 1 bit 42 // 43 // If there's need to increase the number of minor types in the 44 // future, we'll have to increase the size of the latter and hence 45 // decrease the size of the former. 46 // 47 // 00000 0 [ 0] Free 48 // 49 // 00001 0 [ 2] Young Mask 50 // 00001 0 [ 2] Eden 51 // 00001 1 [ 3] Survivor 52 // 53 // 00010 0 [ 4] Humongous Mask 54 // 00100 0 [ 8] Pinned Mask 55 // 00110 0 [12] Starts Humongous 56 // 00110 1 [13] Continues Humongous 57 // 58 // 01000 0 [16] Old Mask 59 // 60 // 10000 0 [32] Archive Mask 61 // 11100 0 [56] Open Archive 62 // 11100 1 [57] Closed Archive 63 // 64 typedef enum { 65 FreeTag = 0, 66 67 YoungMask = 2, 68 EdenTag = YoungMask, 69 SurvTag = YoungMask + 1, 70 71 HumongousMask = 4, 72 PinnedMask = 8, 73 StartsHumongousTag = HumongousMask | PinnedMask, 74 ContinuesHumongousTag = HumongousMask | PinnedMask + 1, 75 76 OldMask = 16, 77 OldTag = OldMask, 78 79 // Archive regions are regions with immutable content (i.e. not reclaimed, and 80 // not allocated into during regular operation). They differ in the kind of references 81 // allowed for the contained objects: 82 // - Closed archive regions form a separate self-contained (closed) object graph 83 // within the set of all of these regions. No references outside of closed 84 // archive regions are allowed. 85 // - Open archive regions have no restrictions on the references of their objects. 86 // Objects within these regions are allowed to have references to objects 87 // contained in any other kind of regions. 88 ArchiveMask = 32, 89 OpenArchiveTag = ArchiveMask | PinnedMask, 90 ClosedArchiveTag = ArchiveMask | PinnedMask + 1 91 } Tag; 92 93 volatile Tag _tag; 94 95 static bool is_valid(Tag tag); 96 97 Tag get() const { 98 hrt_assert_is_valid(_tag); 99 return _tag; 100 } 101 102 // Sets the type to 'tag'. 103 void set(Tag tag) { 104 hrt_assert_is_valid(tag); 105 hrt_assert_is_valid(_tag); 106 _tag = tag; 107 } 108 109 // Sets the type to 'tag', expecting the type to be 'before'. This 110 // is available for when we want to add sanity checking to the type 111 // transition. 112 void set_from(Tag tag, Tag before) { 113 hrt_assert_is_valid(tag); 114 hrt_assert_is_valid(before); 115 hrt_assert_is_valid(_tag); 116 assert(_tag == before, "HR tag: %u, expected: %u new tag; %u", _tag, before, tag); 117 _tag = tag; 118 } 119 120 public: 121 // Queries 122 123 bool is_free() const { return get() == FreeTag; } 124 125 bool is_young() const { return (get() & YoungMask) != 0; } 126 bool is_eden() const { return get() == EdenTag; } 127 bool is_survivor() const { return get() == SurvTag; } 128 129 bool is_humongous() const { return (get() & HumongousMask) != 0; } 130 bool is_starts_humongous() const { return get() == StartsHumongousTag; } 131 bool is_continues_humongous() const { return get() == ContinuesHumongousTag; } 132 133 bool is_archive() const { return (get() & ArchiveMask) != 0; } 134 bool is_open_archive() const { return get() == OpenArchiveTag; } 135 bool is_closed_archive() const { return get() == ClosedArchiveTag; } 136 137 // is_old regions may or may not also be pinned 138 bool is_old() const { return (get() & OldMask) != 0; } 139 140 bool is_old_or_humongous() const { return (get() & (OldMask | HumongousMask)) != 0; } 141 142 bool is_old_or_humongous_or_archive() const { return (get() & (OldMask | HumongousMask | ArchiveMask)) != 0; } 143 144 // is_pinned regions may be archive or humongous 145 bool is_pinned() const { return (get() & PinnedMask) != 0; } 146 147 // Setters 148 149 void set_free() { set(FreeTag); } 150 151 void set_eden() { set_from(EdenTag, FreeTag); } 152 void set_eden_pre_gc() { set_from(EdenTag, SurvTag); } 153 void set_survivor() { set_from(SurvTag, FreeTag); } 154 155 void set_starts_humongous() { set_from(StartsHumongousTag, FreeTag); } 156 void set_continues_humongous() { set_from(ContinuesHumongousTag, FreeTag); } 157 158 void set_old() { set(OldTag); } 159 160 // Change the current region type to be of an old region type if not already done so. 161 // Returns whether the region type has been changed or not. 162 bool relabel_as_old() { 163 //assert(!is_free(), "Should not try to move Free region"); 164 assert(!is_humongous(), "Should not try to move Humongous region"); 165 if (is_old()) { 166 return false; 167 } 168 if (is_eden()) { 169 set_from(OldTag, EdenTag); 170 return true; 171 } else if (is_free()) { 172 set_from(OldTag, FreeTag); 173 return true; 174 } else { 175 set_from(OldTag, SurvTag); 176 return true; 177 } 178 } 179 void set_open_archive() { set_from(OpenArchiveTag, FreeTag); } 180 void set_closed_archive() { set_from(ClosedArchiveTag, FreeTag); } 181 182 // Misc 183 184 const char* get_str() const; 185 const char* get_short_str() const; 186 G1HeapRegionTraceType::Type get_trace_type(); 187 188 HeapRegionType() : _tag(FreeTag) { hrt_assert_is_valid(_tag); } 189 }; 190 191 #endif // SHARE_VM_GC_G1_HEAPREGIONTYPE_HPP