1 /*
2 * Copyright (c) 2005, 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 #include "precompiled.hpp"
26 #include "gc_implementation/parallelScavenge/parMarkBitMap.hpp"
27 #include "gc_implementation/parallelScavenge/psParallelCompact.hpp"
28 #include "oops/oop.inline.hpp"
29 #include "runtime/atomic.inline.hpp"
30 #include "runtime/os.hpp"
31 #include "utilities/bitMap.inline.hpp"
32 #include "services/memTracker.hpp"
33
34 bool
35 ParMarkBitMap::initialize(MemRegion covered_region)
36 {
37 const idx_t bits = bits_required(covered_region);
38 // The bits will be divided evenly between two bitmaps; each of them should be
39 // an integral number of words.
40 assert(bits % (BitsPerWord * 2) == 0, "region size unaligned");
41
42 const size_t words = bits / BitsPerWord;
43 const size_t raw_bytes = words * sizeof(idx_t);
44 const size_t page_sz = os::page_size_for_region(raw_bytes, 10);
45 const size_t granularity = os::vm_allocation_granularity();
46 _reserved_byte_size = align_size_up(raw_bytes, MAX2(page_sz, granularity));
47
48 const size_t rs_align = page_sz == (size_t) os::vm_page_size() ? 0 :
49 MAX2(page_sz, granularity);
50 ReservedSpace rs(_reserved_byte_size, rs_align, rs_align > 0);
51 os::trace_page_sizes("par bitmap", raw_bytes, raw_bytes, page_sz,
52 rs.base(), rs.size());
53
54 MemTracker::record_virtual_memory_type((address)rs.base(), mtGC);
55
56 _virtual_space = new PSVirtualSpace(rs, page_sz);
57 if (_virtual_space != NULL && _virtual_space->expand_by(_reserved_byte_size)) {
58 _region_start = covered_region.start();
59 _region_size = covered_region.word_size();
60 BitMap::bm_word_t* map = (BitMap::bm_word_t*)_virtual_space->reserved_low_addr();
61 _beg_bits.set_map(map);
62 _beg_bits.set_size(bits / 2);
63 _end_bits.set_map(map + words / 2);
64 _end_bits.set_size(bits / 2);
65 return true;
66 }
67
68 _region_start = 0;
69 _region_size = 0;
70 if (_virtual_space != NULL) {
71 delete _virtual_space;
72 _virtual_space = NULL;
73 // Release memory reserved in the space.
74 rs.release();
75 }
76 return false;
77 }
78
79 #ifdef ASSERT
80 extern size_t mark_bitmap_count;
81 extern size_t mark_bitmap_size;
82 #endif // #ifdef ASSERT
83
84 bool
85 ParMarkBitMap::mark_obj(HeapWord* addr, size_t size)
86 {
87 const idx_t beg_bit = addr_to_bit(addr);
88 if (_beg_bits.par_set_bit(beg_bit)) {
89 const idx_t end_bit = addr_to_bit(addr + size - 1);
90 bool end_bit_ok = _end_bits.par_set_bit(end_bit);
91 assert(end_bit_ok, "concurrency problem");
92 DEBUG_ONLY(Atomic::inc_ptr(&mark_bitmap_count));
93 DEBUG_ONLY(Atomic::add_ptr(size, &mark_bitmap_size));
94 return true;
95 }
96 return false;
97 }
98
99 size_t ParMarkBitMap::live_words_in_range(HeapWord* beg_addr, oop end_obj) const
100 {
101 assert(beg_addr <= (HeapWord*)end_obj, "bad range");
102 assert(is_marked(end_obj), "end_obj must be live");
103
104 idx_t live_bits = 0;
105
106 // The bitmap routines require the right boundary to be word-aligned.
107 const idx_t end_bit = addr_to_bit((HeapWord*)end_obj);
108 const idx_t range_end = BitMap::word_align_up(end_bit);
109
110 idx_t beg_bit = find_obj_beg(addr_to_bit(beg_addr), range_end);
111 while (beg_bit < end_bit) {
112 idx_t tmp_end = find_obj_end(beg_bit, range_end);
113 assert(tmp_end < end_bit, "missing end bit");
114 live_bits += tmp_end - beg_bit + 1;
115 beg_bit = find_obj_beg(tmp_end + 1, range_end);
116 }
117 return bits_to_words(live_bits);
118 }
119
120 ParMarkBitMap::IterationStatus
121 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,
122 idx_t range_beg, idx_t range_end) const
123 {
124 DEBUG_ONLY(verify_bit(range_beg);)
125 DEBUG_ONLY(verify_bit(range_end);)
126 assert(range_beg <= range_end, "live range invalid");
127
128 // The bitmap routines require the right boundary to be word-aligned.
129 const idx_t search_end = BitMap::word_align_up(range_end);
130
131 idx_t cur_beg = find_obj_beg(range_beg, search_end);
132 while (cur_beg < range_end) {
133 const idx_t cur_end = find_obj_end(cur_beg, search_end);
134 if (cur_end >= range_end) {
135 // The obj ends outside the range.
136 live_closure->set_source(bit_to_addr(cur_beg));
137 return incomplete;
138 }
139
140 const size_t size = obj_size(cur_beg, cur_end);
141 IterationStatus status = live_closure->do_addr(bit_to_addr(cur_beg), size);
142 if (status != incomplete) {
143 assert(status == would_overflow || status == full, "sanity");
144 return status;
145 }
146
147 // Successfully processed the object; look for the next object.
148 cur_beg = find_obj_beg(cur_end + 1, search_end);
149 }
150
151 live_closure->set_source(bit_to_addr(range_end));
152 return complete;
153 }
154
155 ParMarkBitMap::IterationStatus
156 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,
157 ParMarkBitMapClosure* dead_closure,
158 idx_t range_beg, idx_t range_end,
159 idx_t dead_range_end) const
160 {
161 DEBUG_ONLY(verify_bit(range_beg);)
162 DEBUG_ONLY(verify_bit(range_end);)
163 DEBUG_ONLY(verify_bit(dead_range_end);)
164 assert(range_beg <= range_end, "live range invalid");
165 assert(range_end <= dead_range_end, "dead range invalid");
166
167 // The bitmap routines require the right boundary to be word-aligned.
168 const idx_t live_search_end = BitMap::word_align_up(range_end);
169 const idx_t dead_search_end = BitMap::word_align_up(dead_range_end);
170
171 idx_t cur_beg = range_beg;
172 if (range_beg < range_end && is_unmarked(range_beg)) {
173 // The range starts with dead space. Look for the next object, then fill.
174 cur_beg = find_obj_beg(range_beg + 1, dead_search_end);
175 const idx_t dead_space_end = MIN2(cur_beg - 1, dead_range_end - 1);
176 const size_t size = obj_size(range_beg, dead_space_end);
177 dead_closure->do_addr(bit_to_addr(range_beg), size);
178 }
179
180 while (cur_beg < range_end) {
181 const idx_t cur_end = find_obj_end(cur_beg, live_search_end);
182 if (cur_end >= range_end) {
183 // The obj ends outside the range.
184 live_closure->set_source(bit_to_addr(cur_beg));
185 return incomplete;
186 }
187
188 const size_t size = obj_size(cur_beg, cur_end);
189 IterationStatus status = live_closure->do_addr(bit_to_addr(cur_beg), size);
190 if (status != incomplete) {
191 assert(status == would_overflow || status == full, "sanity");
192 return status;
193 }
194
195 // Look for the start of the next object.
196 const idx_t dead_space_beg = cur_end + 1;
197 cur_beg = find_obj_beg(dead_space_beg, dead_search_end);
198 if (cur_beg > dead_space_beg) {
199 // Found dead space; compute the size and invoke the dead closure.
200 const idx_t dead_space_end = MIN2(cur_beg - 1, dead_range_end - 1);
201 const size_t size = obj_size(dead_space_beg, dead_space_end);
202 dead_closure->do_addr(bit_to_addr(dead_space_beg), size);
203 }
204 }
205
206 live_closure->set_source(bit_to_addr(range_end));
207 return complete;
208 }
209
210 #ifdef ASSERT
211 void ParMarkBitMap::verify_clear() const
212 {
213 const idx_t* const beg = (const idx_t*)_virtual_space->committed_low_addr();
214 const idx_t* const end = (const idx_t*)_virtual_space->committed_high_addr();
215 for (const idx_t* p = beg; p < end; ++p) {
216 assert(*p == 0, "bitmap not clear");
217 }
218 }
219 #endif // #ifdef ASSERT