1 /*
2 * Copyright (c) 2001, 2017, 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.
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23 */
24
25 #ifndef SHARE_VM_GC_G1_G1BLOCKOFFSETTABLE_INLINE_HPP
26 #define SHARE_VM_GC_G1_G1BLOCKOFFSETTABLE_INLINE_HPP
27
28 #include "gc/g1/g1BlockOffsetTable.hpp"
29 #include "gc/g1/heapRegion.hpp"
30 #include "gc/shared/memset_with_concurrent_readers.hpp"
31 #include "gc/shared/space.hpp"
32 #include "runtime/atomic.hpp"
33
block_start(const void * addr)34 inline HeapWord* G1BlockOffsetTablePart::block_start(const void* addr) {
35 if (addr >= _space->bottom() && addr < _space->end()) {
36 HeapWord* q = block_at_or_preceding(addr, true, _next_offset_index-1);
37 return forward_to_block_containing_addr(q, addr);
38 } else {
39 return NULL;
40 }
41 }
42
block_start_const(const void * addr) const43 inline HeapWord* G1BlockOffsetTablePart::block_start_const(const void* addr) const {
44 if (addr >= _space->bottom() && addr < _space->end()) {
45 HeapWord* q = block_at_or_preceding(addr, true, _next_offset_index-1);
46 HeapWord* n = q + block_size(q);
47 return forward_to_block_containing_addr_const(q, n, addr);
48 } else {
49 return NULL;
50 }
51 }
52
offset_array(size_t index) const53 u_char G1BlockOffsetTable::offset_array(size_t index) const {
54 check_index(index, "index out of range");
55 return Atomic::load(&_offset_array[index]);
56 }
57
set_offset_array_raw(size_t index,u_char offset)58 void G1BlockOffsetTable::set_offset_array_raw(size_t index, u_char offset) {
59 Atomic::store(offset, &_offset_array[index]);
60 }
61
set_offset_array(size_t index,u_char offset)62 void G1BlockOffsetTable::set_offset_array(size_t index, u_char offset) {
63 check_index(index, "index out of range");
64 set_offset_array_raw(index, offset);
65 }
66
set_offset_array(size_t index,HeapWord * high,HeapWord * low)67 void G1BlockOffsetTable::set_offset_array(size_t index, HeapWord* high, HeapWord* low) {
68 check_index(index, "index out of range");
69 assert(high >= low, "addresses out of order");
70 size_t offset = pointer_delta(high, low);
71 check_offset(offset, "offset too large");
72 set_offset_array(index, (u_char)offset);
73 }
74
set_offset_array(size_t left,size_t right,u_char offset)75 void G1BlockOffsetTable::set_offset_array(size_t left, size_t right, u_char offset) {
76 check_index(right, "right index out of range");
77 assert(left <= right, "indexes out of order");
78 size_t num_cards = right - left + 1;
79 memset_with_concurrent_readers
80 (const_cast<u_char*> (&_offset_array[left]), offset, num_cards);
81 }
82
83 // Variant of index_for that does not check the index for validity.
index_for_raw(const void * p) const84 inline size_t G1BlockOffsetTable::index_for_raw(const void* p) const {
85 return pointer_delta((char*)p, _reserved.start(), sizeof(char)) >> BOTConstants::LogN;
86 }
87
index_for(const void * p) const88 inline size_t G1BlockOffsetTable::index_for(const void* p) const {
89 char* pc = (char*)p;
90 assert(pc >= (char*)_reserved.start() &&
91 pc < (char*)_reserved.end(),
92 "p (" PTR_FORMAT ") not in reserved [" PTR_FORMAT ", " PTR_FORMAT ")",
93 p2i(p), p2i(_reserved.start()), p2i(_reserved.end()));
94 size_t result = index_for_raw(p);
95 check_index(result, "bad index from address");
96 return result;
97 }
98
address_for_index(size_t index) const99 inline HeapWord* G1BlockOffsetTable::address_for_index(size_t index) const {
100 check_index(index, "index out of range");
101 HeapWord* result = address_for_index_raw(index);
102 assert(result >= _reserved.start() && result < _reserved.end(),
103 "bad address from index result " PTR_FORMAT
104 " _reserved.start() " PTR_FORMAT " _reserved.end() " PTR_FORMAT,
105 p2i(result), p2i(_reserved.start()), p2i(_reserved.end()));
106 return result;
107 }
108
block_size(const HeapWord * p) const109 inline size_t G1BlockOffsetTablePart::block_size(const HeapWord* p) const {
110 return _space->block_size(p);
111 }
112
block_at_or_preceding(const void * addr,bool has_max_index,size_t max_index) const113 inline HeapWord* G1BlockOffsetTablePart::block_at_or_preceding(const void* addr,
114 bool has_max_index,
115 size_t max_index) const {
116 assert(_object_can_span || _bot->offset_array(_bot->index_for(_space->bottom())) == 0,
117 "Object crossed region boundary, found offset %u instead of 0",
118 (uint) _bot->offset_array(_bot->index_for(_space->bottom())));
119 size_t index = _bot->index_for(addr);
120 // We must make sure that the offset table entry we use is valid. If
121 // "addr" is past the end, start at the last known one and go forward.
122 if (has_max_index) {
123 index = MIN2(index, max_index);
124 }
125 HeapWord* q = _bot->address_for_index(index);
126
127 uint offset = _bot->offset_array(index); // Extend u_char to uint.
128 while (offset >= BOTConstants::N_words) {
129 // The excess of the offset from N_words indicates a power of Base
130 // to go back by.
131 size_t n_cards_back = BOTConstants::entry_to_cards_back(offset);
132 q -= (BOTConstants::N_words * n_cards_back);
133 index -= n_cards_back;
134 offset = _bot->offset_array(index);
135 }
136 assert(offset < BOTConstants::N_words, "offset too large");
137 q -= offset;
138 return q;
139 }
140
forward_to_block_containing_addr_const(HeapWord * q,HeapWord * n,const void * addr) const141 inline HeapWord* G1BlockOffsetTablePart::forward_to_block_containing_addr_const(HeapWord* q, HeapWord* n,
142 const void* addr) const {
143 if (addr >= _space->top()) return _space->top();
144 while (n <= addr) {
145 q = n;
146 oop obj = oop(q);
147 if (obj->klass_or_null_acquire() == NULL) {
148 return q;
149 }
150 n += block_size(q);
151 }
152 assert(q <= n, "wrong order for q and addr");
153 assert(addr < n, "wrong order for addr and n");
154 return q;
155 }
156
forward_to_block_containing_addr(HeapWord * q,const void * addr)157 inline HeapWord* G1BlockOffsetTablePart::forward_to_block_containing_addr(HeapWord* q,
158 const void* addr) {
159 if (oop(q)->klass_or_null_acquire() == NULL) {
160 return q;
161 }
162 HeapWord* n = q + block_size(q);
163 // In the normal case, where the query "addr" is a card boundary, and the
164 // offset table chunks are the same size as cards, the block starting at
165 // "q" will contain addr, so the test below will fail, and we'll fall
166 // through quickly.
167 if (n <= addr) {
168 q = forward_to_block_containing_addr_slow(q, n, addr);
169 }
170 assert(q <= addr, "wrong order for current and arg");
171 return q;
172 }
173
174 #endif // SHARE_VM_GC_G1_G1BLOCKOFFSETTABLE_INLINE_HPP
175