rev 6670 : fast reclaim main patch
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 if (_g1h->in_cset_fast_test(obj)) {
56 oop forwardee;
57 if (obj->is_forwarded()) {
58 forwardee = obj->forwardee();
59 } else {
60 forwardee = copy_to_survivor_space(obj);
61 }
62 assert(forwardee != NULL, "forwardee should not be NULL");
63 oopDesc::encode_store_heap_oop(p, forwardee);
64 }
65
66 assert(obj != NULL, "Must be");
67 update_rs(from, p, queue_num());
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(Universe::heap()->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 err_msg("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_raw(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 template <class T> inline void G1ParScanThreadState::deal_with_reference(T* ref_to_scan) {
120 if (!has_partial_array_mask(ref_to_scan)) {
121 // Note: we can use "raw" versions of "region_containing" because
122 // "obj_to_scan" is definitely in the heap, and is not in a
123 // humongous region.
124 HeapRegion* r = _g1h->heap_region_containing_raw(ref_to_scan);
125 do_oop_evac(ref_to_scan, r);
126 } else {
127 do_oop_partial_array((oop*)ref_to_scan);
128 }
129 }
130
131 inline void G1ParScanThreadState::dispatch_reference(StarTask ref) {
132 assert(verify_task(ref), "sanity");
133 if (ref.is_narrow()) {
134 deal_with_reference((narrowOop*)ref);
135 } else {
136 deal_with_reference((oop*)ref);
137 }
138 }
139
140 void G1ParScanThreadState::steal_and_trim_queue(RefToScanQueueSet *task_queues) {
141 StarTask stolen_task;
142 while (task_queues->steal(queue_num(), hash_seed(), stolen_task)) {
143 assert(verify_task(stolen_task), "sanity");
144 dispatch_reference(stolen_task);
145
146 // We've just processed a reference and we might have made
147 // available new entries on the queues. So we have to make sure
148 // we drain the queues as necessary.
149 trim_queue();
150 }
151 }
152
153 #endif /* SHARE_VM_GC_IMPLEMENTATION_G1_G1PARSCANTHREADSTATE_INLINE_HPP */
154
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