1 /*
2 * Copyright (c) 2001, 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
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "gc/parallel/objectStartArray.inline.hpp"
27 #include "gc/shared/cardTableModRefBS.hpp"
28 #include "memory/allocation.inline.hpp"
29 #include "oops/oop.inline.hpp"
30 #include "runtime/java.hpp"
31 #include "services/memTracker.hpp"
32 #include "utilities/align.hpp"
33
34 void ObjectStartArray::initialize(MemRegion reserved_region) {
35 // We're based on the assumption that we use the same
36 // size blocks as the card table.
37 assert((int)block_size == (int)CardTable::card_size, "Sanity");
38 assert((int)block_size <= 512, "block_size must be less than or equal to 512");
39
40 // Calculate how much space must be reserved
41 _reserved_region = reserved_region;
42
43 size_t bytes_to_reserve = reserved_region.word_size() / block_size_in_words;
44 assert(bytes_to_reserve > 0, "Sanity");
45
46 bytes_to_reserve =
47 align_up(bytes_to_reserve, os::vm_allocation_granularity());
48
49 // Do not use large-pages for the backing store. The one large page region
50 // will be used for the heap proper.
51 ReservedSpace backing_store(bytes_to_reserve);
52 if (!backing_store.is_reserved()) {
53 vm_exit_during_initialization("Could not reserve space for ObjectStartArray");
54 }
55 MemTracker::record_virtual_memory_type((address)backing_store.base(), mtGC);
56
57 // We do not commit any memory initially
58 if (!_virtual_space.initialize(backing_store, 0)) {
59 vm_exit_during_initialization("Could not commit space for ObjectStartArray");
60 }
61
62 _raw_base = (jbyte*)_virtual_space.low_boundary();
63
64 if (_raw_base == NULL) {
65 vm_exit_during_initialization("Could not get raw_base address");
66 }
67
68 MemTracker::record_virtual_memory_type((address)_raw_base, mtGC);
69
70
71 _offset_base = _raw_base - (size_t(reserved_region.start()) >> block_shift);
72
73 _covered_region.set_start(reserved_region.start());
74 _covered_region.set_word_size(0);
75
76 _blocks_region.set_start((HeapWord*)_raw_base);
77 _blocks_region.set_word_size(0);
78 }
79
80 void ObjectStartArray::set_covered_region(MemRegion mr) {
81 assert(_reserved_region.contains(mr), "MemRegion outside of reserved space");
82 assert(_reserved_region.start() == mr.start(), "Attempt to move covered region");
83
84 HeapWord* low_bound = mr.start();
85 HeapWord* high_bound = mr.end();
86 assert((uintptr_t(low_bound) & (block_size - 1)) == 0, "heap must start at block boundary");
87 assert((uintptr_t(high_bound) & (block_size - 1)) == 0, "heap must end at block boundary");
88
89 size_t requested_blocks_size_in_bytes = mr.word_size() / block_size_in_words;
90
91 // Only commit memory in page sized chunks
92 requested_blocks_size_in_bytes =
93 align_up(requested_blocks_size_in_bytes, os::vm_page_size());
94
95 _covered_region = mr;
96
97 size_t current_blocks_size_in_bytes = _blocks_region.byte_size();
98
99 if (requested_blocks_size_in_bytes > current_blocks_size_in_bytes) {
100 // Expand
101 size_t expand_by = requested_blocks_size_in_bytes - current_blocks_size_in_bytes;
102 if (!_virtual_space.expand_by(expand_by)) {
103 vm_exit_out_of_memory(expand_by, OOM_MMAP_ERROR, "object start array expansion");
104 }
105 // Clear *only* the newly allocated region
106 memset(_blocks_region.end(), clean_block, expand_by);
107 }
108
109 if (requested_blocks_size_in_bytes < current_blocks_size_in_bytes) {
110 // Shrink
111 size_t shrink_by = current_blocks_size_in_bytes - requested_blocks_size_in_bytes;
112 _virtual_space.shrink_by(shrink_by);
113 }
114
115 _blocks_region.set_word_size(requested_blocks_size_in_bytes / sizeof(HeapWord));
116
117 assert(requested_blocks_size_in_bytes % sizeof(HeapWord) == 0, "Block table not expanded in word sized increment");
118 assert(requested_blocks_size_in_bytes == _blocks_region.byte_size(), "Sanity");
119 assert(block_for_addr(low_bound) == &_raw_base[0], "Checking start of map");
120 assert(block_for_addr(high_bound-1) <= &_raw_base[_blocks_region.byte_size()-1], "Checking end of map");
121 }
122
123 void ObjectStartArray::reset() {
124 memset(_blocks_region.start(), clean_block, _blocks_region.byte_size());
125 }
126
127 bool ObjectStartArray::object_starts_in_range(HeapWord* start_addr,
128 HeapWord* end_addr) const {
129 assert(start_addr <= end_addr,
130 "Range is wrong. start_addr (" PTR_FORMAT ") is after end_addr (" PTR_FORMAT ")",
131 p2i(start_addr), p2i(end_addr));
132 if (start_addr > end_addr) {
133 return false;
134 }
135
136 jbyte* start_block = block_for_addr(start_addr);
137 jbyte* end_block = block_for_addr(end_addr);
138
139 for (jbyte* block = start_block; block <= end_block; block++) {
140 if (*block != clean_block) {
141 return true;
142 }
143 }
144
145 return false;
146 }