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> inline void G1ParScanThreadState::immediate_rs_update(HeapRegion* from, T* p, int tid) {
33 if (!from->is_survivor()) {
34 _g1_rem->par_write_ref(from, p, tid);
35 }
36 }
37
38 template <class T> void G1ParScanThreadState::update_rs(HeapRegion* from, T* p, int tid) {
39 if (G1DeferredRSUpdate) {
40 deferred_rs_update(from, p, tid);
41 } else {
42 immediate_rs_update(from, p, tid);
43 }
44 }
45
46 template <class T> void G1ParScanThreadState::do_oop_evac(T* p, HeapRegion* from) {
47 assert(!oopDesc::is_null(oopDesc::load_decode_heap_oop(p)),
48 "Reference should not be NULL here as such are never pushed to the task queue.");
49 oop obj = oopDesc::load_decode_heap_oop_not_null(p);
50
51 // Although we never intentionally push references outside of the collection
52 // set, due to (benign) races in the claim mechanism during RSet scanning more
53 // than one thread might claim the same card. So the same card may be
54 // processed multiple times. So redo this check.
55 G1CollectedHeap::in_cset_state_t in_cset_state = _g1h->in_cset_state(obj);
56 if (in_cset_state == G1CollectedHeap::InCSet) {
57 oop forwardee;
58 if (obj->is_forwarded()) {
59 forwardee = obj->forwardee();
60 } else {
61 forwardee = copy_to_survivor_space(obj);
62 }
63 oopDesc::encode_store_heap_oop(p, forwardee);
64 } else if (in_cset_state == G1CollectedHeap::IsHumongous) {
65 _g1h->set_humongous_is_live(obj);
66 } else {
67 assert(in_cset_state == G1CollectedHeap::InNeither,
68 err_msg("In_cset_state must be InNeither here, but is %d", in_cset_state));
69 }
70
71 assert(obj != NULL, "Must be");
72 update_rs(from, p, queue_num());
73 }
74
75 inline void G1ParScanThreadState::do_oop_partial_array(oop* p) {
76 assert(has_partial_array_mask(p), "invariant");
77 oop from_obj = clear_partial_array_mask(p);
78
79 assert(Universe::heap()->is_in_reserved(from_obj), "must be in heap.");
80 assert(from_obj->is_objArray(), "must be obj array");
81 objArrayOop from_obj_array = objArrayOop(from_obj);
82 // The from-space object contains the real length.
83 int length = from_obj_array->length();
84
85 assert(from_obj->is_forwarded(), "must be forwarded");
86 oop to_obj = from_obj->forwardee();
87 assert(from_obj != to_obj, "should not be chunking self-forwarded objects");
88 objArrayOop to_obj_array = objArrayOop(to_obj);
89 // We keep track of the next start index in the length field of the
90 // to-space object.
91 int next_index = to_obj_array->length();
92 assert(0 <= next_index && next_index < length,
93 err_msg("invariant, next index: %d, length: %d", next_index, length));
94
95 int start = next_index;
96 int end = length;
97 int remainder = end - start;
98 // We'll try not to push a range that's smaller than ParGCArrayScanChunk.
99 if (remainder > 2 * ParGCArrayScanChunk) {
100 end = start + ParGCArrayScanChunk;
101 to_obj_array->set_length(end);
102 // Push the remainder before we process the range in case another
103 // worker has run out of things to do and can steal it.
104 oop* from_obj_p = set_partial_array_mask(from_obj);
105 push_on_queue(from_obj_p);
106 } else {
107 assert(length == end, "sanity");
108 // We'll process the final range for this object. Restore the length
109 // so that the heap remains parsable in case of evacuation failure.
110 to_obj_array->set_length(end);
111 }
112 _scanner.set_region(_g1h->heap_region_containing_raw(to_obj));
113 // Process indexes [start,end). It will also process the header
114 // along with the first chunk (i.e., the chunk with start == 0).
115 // Note that at this point the length field of to_obj_array is not
116 // correct given that we are using it to keep track of the next
117 // start index. oop_iterate_range() (thankfully!) ignores the length
118 // field and only relies on the start / end parameters. It does
119 // however return the size of the object which will be incorrect. So
120 // we have to ignore it even if we wanted to use it.
121 to_obj_array->oop_iterate_range(&_scanner, start, end);
122 }
123
124 template <class T> inline void G1ParScanThreadState::deal_with_reference(T* ref_to_scan) {
125 if (!has_partial_array_mask(ref_to_scan)) {
126 // Note: we can use "raw" versions of "region_containing" because
127 // "obj_to_scan" is definitely in the heap, and is not in a
128 // humongous region.
129 HeapRegion* r = _g1h->heap_region_containing_raw(ref_to_scan);
130 do_oop_evac(ref_to_scan, r);
131 } else {
132 do_oop_partial_array((oop*)ref_to_scan);
133 }
134 }
135
136 inline void G1ParScanThreadState::dispatch_reference(StarTask ref) {
137 assert(verify_task(ref), "sanity");
138 if (ref.is_narrow()) {
139 deal_with_reference((narrowOop*)ref);
140 } else {
141 deal_with_reference((oop*)ref);
142 }
143 }
144
145 void G1ParScanThreadState::steal_and_trim_queue(RefToScanQueueSet *task_queues) {
146 StarTask stolen_task;
147 while (task_queues->steal(queue_num(), hash_seed(), stolen_task)) {
148 assert(verify_task(stolen_task), "sanity");
149 dispatch_reference(stolen_task);
150
151 // We've just processed a reference and we might have made
152 // available new entries on the queues. So we have to make sure
153 // we drain the queues as necessary.
154 trim_queue();
155 }
156 }
157
158 #endif /* SHARE_VM_GC_IMPLEMENTATION_G1_G1PARSCANTHREADSTATE_INLINE_HPP */
159