1 /* 2 * Copyright (c) 2014, 2015, 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_G1PARSCANTHREADSTATE_INLINE_HPP 26 #define SHARE_VM_GC_G1_G1PARSCANTHREADSTATE_INLINE_HPP 27 28 #include "gc/g1/g1ParScanThreadState.hpp" 29 #include "gc/g1/g1RemSet.hpp" 30 #include "oops/oop.inline.hpp" 31 32 template <class T> void G1ParScanThreadState::do_oop_evac(T* p, HeapRegion* from) { 33 assert(!oopDesc::is_null(oopDesc::load_decode_heap_oop(p)), 34 "Reference should not be NULL here as such are never pushed to the task queue."); 35 oop obj = oopDesc::load_decode_heap_oop_not_null(p); 36 37 // Although we never intentionally push references outside of the collection 38 // set, due to (benign) races in the claim mechanism during RSet scanning more 39 // than one thread might claim the same card. So the same card may be 40 // processed multiple times. So redo this check. 41 const InCSetState in_cset_state = _g1h->in_cset_state(obj); 42 if (in_cset_state.is_in_cset()) { 43 markOop m = obj->mark(); 44 if (m->is_marked()) { 45 obj = (oop) m->decode_pointer(); 46 } else { 47 obj = copy_to_survivor_space(in_cset_state, obj, m); 48 } 49 oopDesc::encode_store_heap_oop(p, obj); 50 } else if (in_cset_state.is_humongous()) { 51 _g1h->set_humongous_is_live(obj); 52 } else { 53 assert(in_cset_state.is_default(), 54 "In_cset_state must be NotInCSet here, but is " CSETSTATE_FORMAT, in_cset_state.value()); 55 } 56 57 assert(obj != NULL, "Must be"); 58 if (!HeapRegion::is_in_same_region(p, obj)) { 59 update_rs(from, p, obj); 60 } 61 } 62 63 template <class T> inline void G1ParScanThreadState::push_on_queue(T* ref) { 64 assert(verify_ref(ref), "sanity"); 65 _refs->push(ref); 66 } 67 68 inline void G1ParScanThreadState::do_oop_partial_array(oop* p) { 69 assert(has_partial_array_mask(p), "invariant"); 70 oop from_obj = clear_partial_array_mask(p); 71 72 assert(_g1h->is_in_reserved(from_obj), "must be in heap."); 73 assert(from_obj->is_objArray(), "must be obj array"); 74 objArrayOop from_obj_array = objArrayOop(from_obj); 75 // The from-space object contains the real length. 76 int length = from_obj_array->length(); 77 78 assert(from_obj->is_forwarded(), "must be forwarded"); 79 oop to_obj = from_obj->forwardee(); 80 assert(from_obj != to_obj, "should not be chunking self-forwarded objects"); 81 objArrayOop to_obj_array = objArrayOop(to_obj); 82 // We keep track of the next start index in the length field of the 83 // to-space object. 84 int next_index = to_obj_array->length(); 85 assert(0 <= next_index && next_index < length, 86 "invariant, next index: %d, length: %d", next_index, length); 87 88 int start = next_index; 89 int end = length; 90 int remainder = end - start; 91 // We'll try not to push a range that's smaller than ParGCArrayScanChunk. 92 if (remainder > 2 * ParGCArrayScanChunk) { 93 end = start + ParGCArrayScanChunk; 94 to_obj_array->set_length(end); 95 // Push the remainder before we process the range in case another 96 // worker has run out of things to do and can steal it. 97 oop* from_obj_p = set_partial_array_mask(from_obj); 98 push_on_queue(from_obj_p); 99 } else { 100 assert(length == end, "sanity"); 101 // We'll process the final range for this object. Restore the length 102 // so that the heap remains parsable in case of evacuation failure. 103 to_obj_array->set_length(end); 104 } 105 _scanner.set_region(_g1h->heap_region_containing(to_obj)); 106 // Process indexes [start,end). It will also process the header 107 // along with the first chunk (i.e., the chunk with start == 0). 108 // Note that at this point the length field of to_obj_array is not 109 // correct given that we are using it to keep track of the next 110 // start index. oop_iterate_range() (thankfully!) ignores the length 111 // field and only relies on the start / end parameters. It does 112 // however return the size of the object which will be incorrect. So 113 // we have to ignore it even if we wanted to use it. 114 to_obj_array->oop_iterate_range(&_scanner, start, end); 115 } 116 117 template <class T> inline void G1ParScanThreadState::deal_with_reference(T* ref_to_scan) { 118 if (!has_partial_array_mask(ref_to_scan)) { 119 HeapRegion* r = _g1h->heap_region_containing(ref_to_scan); 120 do_oop_evac(ref_to_scan, r); 121 } else { 122 do_oop_partial_array((oop*)ref_to_scan); 123 } 124 } 125 126 inline void G1ParScanThreadState::dispatch_reference(StarTask ref) { 127 assert(verify_task(ref), "sanity"); 128 if (ref.is_narrow()) { 129 deal_with_reference((narrowOop*)ref); 130 } else { 131 deal_with_reference((oop*)ref); 132 } 133 } 134 135 void G1ParScanThreadState::steal_and_trim_queue(RefToScanQueueSet *task_queues) { 136 StarTask stolen_task; 137 while (task_queues->steal(_worker_id, &_hash_seed, stolen_task)) { 138 assert(verify_task(stolen_task), "sanity"); 139 dispatch_reference(stolen_task); 140 141 // We've just processed a reference and we might have made 142 // available new entries on the queues. So we have to make sure 143 // we drain the queues as necessary. 144 trim_queue(); 145 } 146 } 147 148 #endif // SHARE_VM_GC_G1_G1PARSCANTHREADSTATE_INLINE_HPP 149