1 /* 2 * Copyright (c) 2014, 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_IMPLEMENTATION_G1_G1PARSCANTHREADSTATE_INLINE_HPP 26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1PARSCANTHREADSTATE_INLINE_HPP 27 28 #include "gc_implementation/g1/g1ParScanThreadState.hpp" 29 #include "gc_implementation/g1/g1RemSet.inline.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 G1CollectedHeap::in_cset_state_t in_cset_state = _g1h->in_cset_state(obj); 42 if (in_cset_state == G1CollectedHeap::InCSet) { 43 oop forwardee; 44 markOop m = obj->mark(); 45 if (m->is_marked()) { 46 forwardee = (oop) m->decode_pointer(); 47 } else { 48 forwardee = copy_to_survivor_space(obj, m); 49 } 50 oopDesc::encode_store_heap_oop(p, forwardee); 51 } else if (in_cset_state == G1CollectedHeap::IsHumongous) { 52 _g1h->set_humongous_is_live(obj); 53 } else { 54 assert(in_cset_state == G1CollectedHeap::InNeither, 55 err_msg("In_cset_state must be InNeither here, but is %d", in_cset_state)); 56 } 57 58 assert(obj != NULL, "Must be"); 59 update_rs(from, p, queue_num()); 60 } 61 62 inline void G1ParScanThreadState::do_oop_partial_array(oop* p) { 63 assert(has_partial_array_mask(p), "invariant"); 64 oop from_obj = clear_partial_array_mask(p); 65 66 assert(Universe::heap()->is_in_reserved(from_obj), "must be in heap."); 67 assert(from_obj->is_objArray(), "must be obj array"); 68 objArrayOop from_obj_array = objArrayOop(from_obj); 69 // The from-space object contains the real length. 70 int length = from_obj_array->length(); 71 72 assert(from_obj->is_forwarded(), "must be forwarded"); 73 oop to_obj = from_obj->forwardee(); 74 assert(from_obj != to_obj, "should not be chunking self-forwarded objects"); 75 objArrayOop to_obj_array = objArrayOop(to_obj); 76 // We keep track of the next start index in the length field of the 77 // to-space object. 78 int next_index = to_obj_array->length(); 79 assert(0 <= next_index && next_index < length, 80 err_msg("invariant, next index: %d, length: %d", next_index, length)); 81 82 int start = next_index; 83 int end = length; 84 int remainder = end - start; 85 // We'll try not to push a range that's smaller than ParGCArrayScanChunk. 86 if (remainder > 2 * ParGCArrayScanChunk) { 87 end = start + ParGCArrayScanChunk; 88 to_obj_array->set_length(end); 89 // Push the remainder before we process the range in case another 90 // worker has run out of things to do and can steal it. 91 oop* from_obj_p = set_partial_array_mask(from_obj); 92 push_on_queue(from_obj_p); 93 } else { 94 assert(length == end, "sanity"); 95 // We'll process the final range for this object. Restore the length 96 // so that the heap remains parsable in case of evacuation failure. 97 to_obj_array->set_length(end); 98 } 99 _scanner.set_region(_g1h->heap_region_containing_raw(to_obj)); 100 // Process indexes [start,end). It will also process the header 101 // along with the first chunk (i.e., the chunk with start == 0). 102 // Note that at this point the length field of to_obj_array is not 103 // correct given that we are using it to keep track of the next 104 // start index. oop_iterate_range() (thankfully!) ignores the length 105 // field and only relies on the start / end parameters. It does 106 // however return the size of the object which will be incorrect. So 107 // we have to ignore it even if we wanted to use it. 108 to_obj_array->oop_iterate_range(&_scanner, start, end); 109 } 110 111 template <class T> inline void G1ParScanThreadState::deal_with_reference(T* ref_to_scan) { 112 if (!has_partial_array_mask(ref_to_scan)) { 113 // Note: we can use "raw" versions of "region_containing" because 114 // "obj_to_scan" is definitely in the heap, and is not in a 115 // humongous region. 116 HeapRegion* r = _g1h->heap_region_containing_raw(ref_to_scan); 117 do_oop_evac(ref_to_scan, r); 118 } else { 119 do_oop_partial_array((oop*)ref_to_scan); 120 } 121 } 122 123 inline void G1ParScanThreadState::dispatch_reference(StarTask ref) { 124 assert(verify_task(ref), "sanity"); 125 if (ref.is_narrow()) { 126 deal_with_reference((narrowOop*)ref); 127 } else { 128 deal_with_reference((oop*)ref); 129 } 130 } 131 132 void G1ParScanThreadState::steal_and_trim_queue(RefToScanQueueSet *task_queues) { 133 StarTask stolen_task; 134 while (task_queues->steal(queue_num(), hash_seed(), stolen_task)) { 135 assert(verify_task(stolen_task), "sanity"); 136 dispatch_reference(stolen_task); 137 138 // We've just processed a reference and we might have made 139 // available new entries on the queues. So we have to make sure 140 // we drain the queues as necessary. 141 trim_queue(); 142 } 143 } 144 145 #endif /* SHARE_VM_GC_IMPLEMENTATION_G1_G1PARSCANTHREADSTATE_INLINE_HPP */ 146