1 /* 2 * Copyright (c) 2017, 2020, 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 "memory/metaspaceClosure.hpp" 27 28 // Update the reference to point to new_loc. 29 void MetaspaceClosure::Ref::update(address new_loc) const { 30 log_trace(cds)("Ref: [" PTR_FORMAT "] -> " PTR_FORMAT " => " PTR_FORMAT, 31 p2i(mpp()), p2i(obj()), p2i(new_loc)); 32 uintx p = (uintx)new_loc; 33 p |= flag_bits(); // Make sure the flag bits are copied to the new pointer. 34 *(address*)mpp() = (address)p; 35 } 36 37 void MetaspaceClosure::push_impl(MetaspaceClosure::Ref* ref) { 38 if (_nest_level < MAX_NEST_LEVEL) { 39 do_push(ref); 40 if (!ref->keep_after_pushing()) { 41 delete ref; 42 } 43 } else { 44 do_pending_ref(ref); 45 ref->set_next(_pending_refs); 46 _pending_refs = ref; 47 } 48 } 49 50 void MetaspaceClosure::do_push(MetaspaceClosure::Ref* ref) { 51 if (ref->not_null()) { 52 bool read_only; 53 Writability w = ref->writability(); 54 switch (w) { 55 case _writable: 56 read_only = false; 57 break; 58 case _not_writable: 59 read_only = true; 60 break; 61 default: 62 assert(w == _default, "must be"); 63 read_only = ref->is_read_only_by_default(); 64 } 65 if (_nest_level == 0) { 66 assert(_enclosing_ref == NULL, "must be"); 67 } 68 _nest_level ++; 69 if (do_ref(ref, read_only)) { // true means we want to iterate the embedded pointer in <ref> 70 Ref* saved = _enclosing_ref; 71 _enclosing_ref = ref; 72 ref->metaspace_pointers_do(this); 73 _enclosing_ref = saved; 74 } 75 _nest_level --; 76 } 77 } 78 79 void MetaspaceClosure::finish() { 80 assert(_nest_level == 0, "must be"); 81 while (_pending_refs != NULL) { 82 Ref* ref = _pending_refs; 83 _pending_refs = _pending_refs->next(); 84 do_push(ref); 85 if (!ref->keep_after_pushing()) { 86 delete ref; 87 } 88 } 89 } 90 91 MetaspaceClosure::~MetaspaceClosure() { 92 assert(_pending_refs == NULL, 93 "you must explicitly call MetaspaceClosure::finish() to process all refs!"); 94 } 95 96 bool UniqueMetaspaceClosure::do_ref(MetaspaceClosure::Ref* ref, bool read_only) { 97 bool* found = _has_been_visited.lookup(ref->obj()); 98 if (found != NULL) { 99 assert(*found == read_only, "must be"); 100 return false; // Already visited: no need to iterate embedded pointers. 101 } else { 102 _has_been_visited.add(ref->obj(), read_only); 103 if (_has_been_visited.maybe_grow(MAX_TABLE_SIZE)) { 104 log_info(cds, hashtables)("Expanded _has_been_visited table to %d", _has_been_visited.table_size()); 105 } 106 return do_unique_ref(ref, read_only); 107 } 108 }