objectStartArray.cpp revision 9056:dc9930a04ab0 
1/*
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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.
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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#include "precompiled.hpp"
26#include "gc/parallel/objectStartArray.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
33void ObjectStartArray::initialize(MemRegion reserved_region) {
34  // We're based on the assumption that we use the same
35  // size blocks as the card table.
36  assert((int)block_size == (int)CardTableModRefBS::card_size, "Sanity");
37  assert((int)block_size <= 512, "block_size must be less than or equal to 512");
38
39  // Calculate how much space must be reserved
40  _reserved_region = reserved_region;
41
42  size_t bytes_to_reserve = reserved_region.word_size() / block_size_in_words;
43  assert(bytes_to_reserve > 0, "Sanity");
44
45  bytes_to_reserve =
46    align_size_up(bytes_to_reserve, os::vm_allocation_granularity());
47
48  // Do not use large-pages for the backing store. The one large page region
49  // will be used for the heap proper.
50  ReservedSpace backing_store(bytes_to_reserve);
51  if (!backing_store.is_reserved()) {
52    vm_exit_during_initialization("Could not reserve space for ObjectStartArray");
53  }
54  MemTracker::record_virtual_memory_type((address)backing_store.base(), mtGC);
55
56  // We do not commit any memory initially
57  if (!_virtual_space.initialize(backing_store, 0)) {
58    vm_exit_during_initialization("Could not commit space for ObjectStartArray");
59  }
60
61  _raw_base = (jbyte*)_virtual_space.low_boundary();
62
63  if (_raw_base == NULL) {
64    vm_exit_during_initialization("Could not get raw_base address");
65  }
66
67  MemTracker::record_virtual_memory_type((address)_raw_base, mtGC);
68
69
70  _offset_base = _raw_base - (size_t(reserved_region.start()) >> block_shift);
71
72  _covered_region.set_start(reserved_region.start());
73  _covered_region.set_word_size(0);
74
75  _blocks_region.set_start((HeapWord*)_raw_base);
76  _blocks_region.set_word_size(0);
77}
78
79void ObjectStartArray::set_covered_region(MemRegion mr) {
80  assert(_reserved_region.contains(mr), "MemRegion outside of reserved space");
81  assert(_reserved_region.start() == mr.start(), "Attempt to move covered region");
82
83  HeapWord* low_bound  = mr.start();
84  HeapWord* high_bound = mr.end();
85  assert((uintptr_t(low_bound)  & (block_size - 1))  == 0, "heap must start at block boundary");
86  assert((uintptr_t(high_bound) & (block_size - 1))  == 0, "heap must end at block boundary");
87
88  size_t requested_blocks_size_in_bytes = mr.word_size() / block_size_in_words;
89
90  // Only commit memory in page sized chunks
91  requested_blocks_size_in_bytes =
92    align_size_up(requested_blocks_size_in_bytes, os::vm_page_size());
93
94  _covered_region = mr;
95
96  size_t current_blocks_size_in_bytes = _blocks_region.byte_size();
97
98  if (requested_blocks_size_in_bytes > current_blocks_size_in_bytes) {
99    // Expand
100    size_t expand_by = requested_blocks_size_in_bytes - current_blocks_size_in_bytes;
101    if (!_virtual_space.expand_by(expand_by)) {
102      vm_exit_out_of_memory(expand_by, OOM_MMAP_ERROR, "object start array expansion");
103    }
104    // Clear *only* the newly allocated region
105    memset(_blocks_region.end(), clean_block, expand_by);
106  }
107
108  if (requested_blocks_size_in_bytes < current_blocks_size_in_bytes) {
109    // Shrink
110    size_t shrink_by = current_blocks_size_in_bytes - requested_blocks_size_in_bytes;
111    _virtual_space.shrink_by(shrink_by);
112  }
113
114  _blocks_region.set_word_size(requested_blocks_size_in_bytes / sizeof(HeapWord));
115
116  assert(requested_blocks_size_in_bytes % sizeof(HeapWord) == 0, "Block table not expanded in word sized increment");
117  assert(requested_blocks_size_in_bytes == _blocks_region.byte_size(), "Sanity");
118  assert(block_for_addr(low_bound) == &_raw_base[0], "Checking start of map");
119  assert(block_for_addr(high_bound-1) <= &_raw_base[_blocks_region.byte_size()-1], "Checking end of map");
120}
121
122void ObjectStartArray::reset() {
123  memset(_blocks_region.start(), clean_block, _blocks_region.byte_size());
124}
125
126
127bool 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}
147