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
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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/access.inline.hpp"
31 #include "oops/oop.inline.hpp"
32
33 template <class T> void G1ParScanThreadState::do_oop_evac(T* p) {
34 // Reference should not be NULL here as such are never pushed to the task queue.
35 oop obj = RawAccess<OOP_NOT_NULL>::oop_load(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, and so we might get references into old gen here.
41 // So we need to redo this check.
42 const InCSetState in_cset_state = _g1h->in_cset_state(obj);
43 if (in_cset_state.is_in_cset()) {
44 markOop m = obj->mark_raw();
45 if (m->is_marked()) {
46 obj = (oop) m->decode_pointer();
47 } else {
48 obj = copy_to_survivor_space(in_cset_state, obj, m);
49 }
50 RawAccess<OOP_NOT_NULL>::oop_store(p, obj);
51 } else if (in_cset_state.is_humongous()) {
52 _g1h->set_humongous_is_live(obj);
53 } else {
54 assert(in_cset_state.is_default(),
55 "In_cset_state must be NotInCSet here, but is " CSETSTATE_FORMAT, in_cset_state.value());
56 }
57
58 assert(obj != NULL, "Must be");
59 if (!HeapRegion::is_in_same_region(p, obj)) {
60 HeapRegion* from = _g1h->heap_region_containing(p);
61 update_rs(from, p, obj);
62 }
63 }
64
65 template <class T> inline void G1ParScanThreadState::push_on_queue(T* ref) {
66 assert(verify_ref(ref), "sanity");
67 _refs->push(ref);
68 }
69
70 inline void G1ParScanThreadState::do_oop_partial_array(oop* p) {
71 assert(has_partial_array_mask(p), "invariant");
72 oop from_obj = clear_partial_array_mask(p);
73
74 assert(_g1h->is_in_reserved(from_obj), "must be in heap.");
75 assert(from_obj->is_objArray(), "must be obj array");
76 objArrayOop from_obj_array = objArrayOop(from_obj);
77 // The from-space object contains the real length.
78 int length = from_obj_array->length();
79
80 assert(from_obj->is_forwarded(), "must be forwarded");
81 oop to_obj = from_obj->forwardee();
82 assert(from_obj != to_obj, "should not be chunking self-forwarded objects");
83 objArrayOop to_obj_array = objArrayOop(to_obj);
84 // We keep track of the next start index in the length field of the
85 // to-space object.
86 int next_index = to_obj_array->length();
87 assert(0 <= next_index && next_index < length,
88 "invariant, next index: %d, length: %d", next_index, length);
89
90 int start = next_index;
91 int end = length;
92 int remainder = end - start;
93 // We'll try not to push a range that's smaller than ParGCArrayScanChunk.
94 if (remainder > 2 * ParGCArrayScanChunk) {
95 end = start + ParGCArrayScanChunk;
96 to_obj_array->set_length(end);
97 // Push the remainder before we process the range in case another
98 // worker has run out of things to do and can steal it.
99 oop* from_obj_p = set_partial_array_mask(from_obj);
100 push_on_queue(from_obj_p);
101 } else {
102 assert(length == end, "sanity");
103 // We'll process the final range for this object. Restore the length
104 // so that the heap remains parsable in case of evacuation failure.
105 to_obj_array->set_length(end);
106 }
107 _scanner.set_region(_g1h->heap_region_containing(to_obj));
108 // Process indexes [start,end). It will also process the header
109 // along with the first chunk (i.e., the chunk with start == 0).
110 // Note that at this point the length field of to_obj_array is not
111 // correct given that we are using it to keep track of the next
112 // start index. oop_iterate_range() (thankfully!) ignores the length
113 // field and only relies on the start / end parameters. It does
114 // however return the size of the object which will be incorrect. So
115 // we have to ignore it even if we wanted to use it.
116 to_obj_array->oop_iterate_range(&_scanner, start, end);
117 }
118
119 inline void G1ParScanThreadState::deal_with_reference(oop* ref_to_scan) {
120 if (!has_partial_array_mask(ref_to_scan)) {
121 do_oop_evac(ref_to_scan);
122 } else {
123 do_oop_partial_array(ref_to_scan);
124 }
125 }
126
127 inline void G1ParScanThreadState::deal_with_reference(narrowOop* ref_to_scan) {
128 assert(!has_partial_array_mask(ref_to_scan), "NarrowOop* elements should never be partial arrays.");
129 do_oop_evac(ref_to_scan);
130 }
131
132 inline void G1ParScanThreadState::dispatch_reference(StarTask ref) {
133 assert(verify_task(ref), "sanity");
134 if (ref.is_narrow()) {
135 deal_with_reference((narrowOop*)ref);
136 } else {
137 deal_with_reference((oop*)ref);
138 }
139 }
140
141 void G1ParScanThreadState::steal_and_trim_queue(RefToScanQueueSet *task_queues) {
142 StarTask stolen_task;
143 while (task_queues->steal(_worker_id, &_hash_seed, stolen_task)) {
144 assert(verify_task(stolen_task), "sanity");
145 dispatch_reference(stolen_task);
146
147 // We've just processed a reference and we might have made
148 // available new entries on the queues. So we have to make sure
149 // we drain the queues as necessary.
150 trim_queue();
151 }
152 }
153
154 #endif // SHARE_VM_GC_G1_G1PARSCANTHREADSTATE_INLINE_HPP