1 /* 2 * Copyright (c) 2015, 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 #include "precompiled.hpp" 26 #include "gc/g1/g1OopClosures.inline.hpp" 27 #include "gc/g1/g1RootClosures.hpp" 28 #include "gc/g1/g1SharedClosures.hpp" 29 30 // Closures used for standard G1 evacuation. 31 class G1EvacuationClosures : public G1EvacuationRootClosures { 32 G1SharedClosures<G1MarkNone> _closures; 33 34 public: 35 G1EvacuationClosures(G1CollectedHeap* g1h, 36 G1ParScanThreadState* pss, 37 bool in_young_gc) : 38 _closures(g1h, pss, in_young_gc, /* cld_claim */ ClassLoaderData::_claim_none) {} 39 40 OopClosure* weak_oops() { return &_closures._oops; } 41 OopClosure* strong_oops() { return &_closures._oops; } 42 43 CLDClosure* weak_clds() { return &_closures._clds; } 44 CLDClosure* strong_clds() { return &_closures._clds; } 45 CLDClosure* second_pass_weak_clds() { return NULL; } 46 47 CodeBlobClosure* strong_codeblobs() { return &_closures._codeblobs; } 48 CodeBlobClosure* weak_codeblobs() { return &_closures._codeblobs; } 49 50 bool trace_metadata() { return false; } 51 }; 52 53 // Closures used during initial mark. 54 // The treatment of "weak" roots is selectable through the template parameter, 55 // this is usually used to control unloading of classes and interned strings. 56 template <G1Mark MarkWeak> 57 class G1InitialMarkClosures : public G1EvacuationRootClosures { 58 G1SharedClosures<G1MarkFromRoot> _strong; 59 G1SharedClosures<MarkWeak> _weak; 60 61 // Filter method to help with returning the appropriate closures 62 // depending on the class template parameter. 63 template <G1Mark Mark, typename T> 64 T* null_if(T* t) { 65 if (Mark == MarkWeak) { 66 return NULL; 67 } 68 return t; 69 } 70 71 public: 72 G1InitialMarkClosures(G1CollectedHeap* g1h, 73 G1ParScanThreadState* pss) : 74 _strong(g1h, pss, /* process_only_dirty_klasses */ false, /* cld_claim */ ClassLoaderData::_claim_strong), 75 _weak(g1h, pss, /* process_only_dirty_klasses */ false, /* cld_claim */ ClassLoaderData::_claim_strong) {} 76 77 OopClosure* weak_oops() { return &_weak._oops; } 78 OopClosure* strong_oops() { return &_strong._oops; } 79 80 // If MarkWeak is G1MarkPromotedFromRoot then the weak CLDs must be processed in a second pass. 81 CLDClosure* weak_clds() { return null_if<G1MarkPromotedFromRoot>(&_weak._clds); } 82 CLDClosure* strong_clds() { return &_strong._clds; } 83 84 // If MarkWeak is G1MarkFromRoot then all CLDs are processed by the weak and strong variants 85 // return a NULL closure for the following specialized versions in that case. 86 CLDClosure* second_pass_weak_clds() { return null_if<G1MarkFromRoot>(&_weak._clds); } 87 88 CodeBlobClosure* strong_codeblobs() { return &_strong._codeblobs; } 89 CodeBlobClosure* weak_codeblobs() { return &_weak._codeblobs; } 90 91 // If we are not marking all weak roots then we are tracing 92 // which metadata is alive. 93 bool trace_metadata() { return MarkWeak == G1MarkPromotedFromRoot; } 94 }; 95 96 G1EvacuationRootClosures* G1EvacuationRootClosures::create_root_closures(G1ParScanThreadState* pss, G1CollectedHeap* g1h) { 97 G1EvacuationRootClosures* res = NULL; 98 if (g1h->collector_state()->in_initial_mark_gc()) { 99 if (ClassUnloadingWithConcurrentMark) { 100 res = new G1InitialMarkClosures<G1MarkPromotedFromRoot>(g1h, pss); 101 } else { 102 res = new G1InitialMarkClosures<G1MarkFromRoot>(g1h, pss); 103 } 104 } else { 105 res = new G1EvacuationClosures(g1h, pss, g1h->collector_state()->in_young_only_phase()); 106 } 107 return res; 108 }