1 /*
2 * Copyright (c) 2005, 2010, 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/parMarkBitMap.inline.hpp"
28 #include "gc_implementation/parallelScavenge/psParallelCompact.hpp"
29 #include "oops/oop.inline.hpp"
30 #include "runtime/os.hpp"
31 #include "utilities/bitMap.inline.hpp"
32 #ifdef TARGET_OS_FAMILY_linux
33 # include "os_linux.inline.hpp"
34 #endif
35 #ifdef TARGET_OS_FAMILY_solaris
36 # include "os_solaris.inline.hpp"
37 #endif
38 #ifdef TARGET_OS_FAMILY_windows
39 # include "os_windows.inline.hpp"
40 #endif
41
42 bool
43 ParMarkBitMap::initialize(MemRegion covered_region)
44 {
45 const idx_t bits = bits_required(covered_region);
46 // The bits will be divided evenly between two bitmaps; each of them should be
47 // an integral number of words.
48 assert(bits % (BitsPerWord * 2) == 0, "region size unaligned");
49
50 const size_t words = bits / BitsPerWord;
51 const size_t raw_bytes = words * sizeof(idx_t);
52 const size_t page_sz = os::page_size_for_region(raw_bytes, raw_bytes, 10);
53 const size_t granularity = os::vm_allocation_granularity();
54 const size_t bytes = align_size_up(raw_bytes, MAX2(page_sz, granularity));
55
56 const size_t rs_align = page_sz == (size_t) os::vm_page_size() ? 0 :
57 MAX2(page_sz, granularity);
58 ReservedSpace rs(bytes, rs_align, rs_align > 0);
59 os::trace_page_sizes("par bitmap", raw_bytes, raw_bytes, page_sz,
60 rs.base(), rs.size());
61 _virtual_space = new PSVirtualSpace(rs, page_sz);
62 if (_virtual_space != NULL && _virtual_space->expand_by(bytes)) {
63 _region_start = covered_region.start();
64 _region_size = covered_region.word_size();
65 idx_t* map = (idx_t*)_virtual_space->reserved_low_addr();
66 _beg_bits.set_map(map);
67 _beg_bits.set_size(bits / 2);
68 _end_bits.set_map(map + words / 2);
69 _end_bits.set_size(bits / 2);
70 return true;
71 }
72
73 _region_start = 0;
74 _region_size = 0;
75 if (_virtual_space != NULL) {
76 delete _virtual_space;
77 _virtual_space = NULL;
78 // Release memory reserved in the space.
79 rs.release();
80 }
81 return false;
82 }
83
84 #ifdef ASSERT
85 extern size_t mark_bitmap_count;
86 extern size_t mark_bitmap_size;
87 #endif // #ifdef ASSERT
88
89 bool
90 ParMarkBitMap::mark_obj(HeapWord* addr, size_t size)
91 {
92 const idx_t beg_bit = addr_to_bit(addr);
93 if (_beg_bits.par_set_bit(beg_bit)) {
94 const idx_t end_bit = addr_to_bit(addr + size - 1);
95 bool end_bit_ok = _end_bits.par_set_bit(end_bit);
96 assert(end_bit_ok, "concurrency problem");
97 DEBUG_ONLY(Atomic::inc_ptr(&mark_bitmap_count));
98 DEBUG_ONLY(Atomic::add_ptr(size, &mark_bitmap_size));
99 return true;
100 }
101 return false;
102 }
103
104 size_t
105 ParMarkBitMap::live_words_in_range(HeapWord* beg_addr, HeapWord* end_addr) const
106 {
107 assert(beg_addr <= end_addr, "bad range");
108
109 idx_t live_bits = 0;
110
111 // The bitmap routines require the right boundary to be word-aligned.
112 const idx_t end_bit = addr_to_bit(end_addr);
113 const idx_t range_end = BitMap::word_align_up(end_bit);
114
115 idx_t beg_bit = find_obj_beg(addr_to_bit(beg_addr), range_end);
116 while (beg_bit < end_bit) {
117 idx_t tmp_end = find_obj_end(beg_bit, range_end);
118 if (tmp_end < end_bit) {
119 live_bits += tmp_end - beg_bit + 1;
120 beg_bit = find_obj_beg(tmp_end + 1, range_end);
121 } else {
122 live_bits += end_bit - beg_bit; // No + 1 here; end_bit is not counted.
123 return bits_to_words(live_bits);
124 }
125 }
126 return bits_to_words(live_bits);
127 }
128
129 size_t ParMarkBitMap::live_words_in_range(HeapWord* beg_addr, oop end_obj) const
130 {
131 assert(beg_addr <= (HeapWord*)end_obj, "bad range");
132 assert(is_marked(end_obj), "end_obj must be live");
133
134 idx_t live_bits = 0;
135
136 // The bitmap routines require the right boundary to be word-aligned.
137 const idx_t end_bit = addr_to_bit((HeapWord*)end_obj);
138 const idx_t range_end = BitMap::word_align_up(end_bit);
139
140 idx_t beg_bit = find_obj_beg(addr_to_bit(beg_addr), range_end);
141 while (beg_bit < end_bit) {
142 idx_t tmp_end = find_obj_end(beg_bit, range_end);
143 assert(tmp_end < end_bit, "missing end bit");
144 live_bits += tmp_end - beg_bit + 1;
145 beg_bit = find_obj_beg(tmp_end + 1, range_end);
146 }
147 return bits_to_words(live_bits);
148 }
149
150 ParMarkBitMap::IterationStatus
151 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,
152 idx_t range_beg, idx_t range_end) const
153 {
154 DEBUG_ONLY(verify_bit(range_beg);)
155 DEBUG_ONLY(verify_bit(range_end);)
156 assert(range_beg <= range_end, "live range invalid");
157
158 // The bitmap routines require the right boundary to be word-aligned.
159 const idx_t search_end = BitMap::word_align_up(range_end);
160
161 idx_t cur_beg = find_obj_beg(range_beg, search_end);
162 while (cur_beg < range_end) {
163 const idx_t cur_end = find_obj_end(cur_beg, search_end);
164 if (cur_end >= range_end) {
165 // The obj ends outside the range.
166 live_closure->set_source(bit_to_addr(cur_beg));
167 return incomplete;
168 }
169
170 const size_t size = obj_size(cur_beg, cur_end);
171 IterationStatus status = live_closure->do_addr(bit_to_addr(cur_beg), size);
172 if (status != incomplete) {
173 assert(status == would_overflow || status == full, "sanity");
174 return status;
175 }
176
177 // Successfully processed the object; look for the next object.
178 cur_beg = find_obj_beg(cur_end + 1, search_end);
179 }
180
181 live_closure->set_source(bit_to_addr(range_end));
182 return complete;
183 }
184
185 ParMarkBitMap::IterationStatus
186 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,
187 ParMarkBitMapClosure* dead_closure,
188 idx_t range_beg, idx_t range_end,
189 idx_t dead_range_end) const
190 {
191 DEBUG_ONLY(verify_bit(range_beg);)
192 DEBUG_ONLY(verify_bit(range_end);)
193 DEBUG_ONLY(verify_bit(dead_range_end);)
194 assert(range_beg <= range_end, "live range invalid");
195 assert(range_end <= dead_range_end, "dead range invalid");
196
197 // The bitmap routines require the right boundary to be word-aligned.
198 const idx_t live_search_end = BitMap::word_align_up(range_end);
199 const idx_t dead_search_end = BitMap::word_align_up(dead_range_end);
200
201 idx_t cur_beg = range_beg;
202 if (range_beg < range_end && is_unmarked(range_beg)) {
203 // The range starts with dead space. Look for the next object, then fill.
204 cur_beg = find_obj_beg(range_beg + 1, dead_search_end);
205 const idx_t dead_space_end = MIN2(cur_beg - 1, dead_range_end - 1);
206 const size_t size = obj_size(range_beg, dead_space_end);
207 dead_closure->do_addr(bit_to_addr(range_beg), size);
208 }
209
210 while (cur_beg < range_end) {
211 const idx_t cur_end = find_obj_end(cur_beg, live_search_end);
212 if (cur_end >= range_end) {
213 // The obj ends outside the range.
214 live_closure->set_source(bit_to_addr(cur_beg));
215 return incomplete;
216 }
217
218 const size_t size = obj_size(cur_beg, cur_end);
219 IterationStatus status = live_closure->do_addr(bit_to_addr(cur_beg), size);
220 if (status != incomplete) {
221 assert(status == would_overflow || status == full, "sanity");
222 return status;
223 }
224
225 // Look for the start of the next object.
226 const idx_t dead_space_beg = cur_end + 1;
227 cur_beg = find_obj_beg(dead_space_beg, dead_search_end);
228 if (cur_beg > dead_space_beg) {
229 // Found dead space; compute the size and invoke the dead closure.
230 const idx_t dead_space_end = MIN2(cur_beg - 1, dead_range_end - 1);
231 const size_t size = obj_size(dead_space_beg, dead_space_end);
232 dead_closure->do_addr(bit_to_addr(dead_space_beg), size);
233 }
234 }
235
236 live_closure->set_source(bit_to_addr(range_end));
237 return complete;
238 }
239
240 #ifndef PRODUCT
241 void ParMarkBitMap::reset_counters()
242 {
243 _cas_tries = _cas_retries = _cas_by_another = 0;
244 }
245 #endif // #ifndef PRODUCT
246
247 #ifdef ASSERT
248 void ParMarkBitMap::verify_clear() const
249 {
250 const idx_t* const beg = (const idx_t*)_virtual_space->committed_low_addr();
251 const idx_t* const end = (const idx_t*)_virtual_space->committed_high_addr();
252 for (const idx_t* p = beg; p < end; ++p) {
253 assert(*p == 0, "bitmap not clear");
254 }
255 }
256 #endif // #ifdef ASSERT