1 /*
2 * Copyright (c) 2005, 2013, 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 #include "services/memTracker.hpp"
33 #ifdef TARGET_OS_FAMILY_linux
34 # include "os_linux.inline.hpp"
35 #endif
36 #ifdef TARGET_OS_FAMILY_solaris
37 # include "os_solaris.inline.hpp"
38 #endif
39 #ifdef TARGET_OS_FAMILY_windows
40 # include "os_windows.inline.hpp"
41 #endif
42 #ifdef TARGET_OS_FAMILY_bsd
43 # include "os_bsd.inline.hpp"
44 #endif
45
46 bool
47 ParMarkBitMap::initialize(MemRegion covered_region)
48 {
49 const idx_t bits = bits_required(covered_region);
50 // The bits will be divided evenly between two bitmaps; each of them should be
51 // an integral number of words.
52 assert(bits % (BitsPerWord * 2) == 0, "region size unaligned");
53
54 const size_t words = bits / BitsPerWord;
55 const size_t raw_bytes = words * sizeof(idx_t);
56 const size_t page_sz = os::page_size_for_region(raw_bytes, raw_bytes, 10);
57 const size_t granularity = os::vm_allocation_granularity();
58 const size_t bytes = align_size_up(raw_bytes, MAX2(page_sz, granularity));
59
60 const size_t rs_align = page_sz == (size_t) os::vm_page_size() ? 0 :
61 MAX2(page_sz, granularity);
62 ReservedSpace rs(bytes, rs_align, rs_align > 0);
63 os::trace_page_sizes("par bitmap", raw_bytes, raw_bytes, page_sz,
64 rs.base(), rs.size());
65
66 NMTTrackOp op(NMTTrackOp::TypeOp);
67 op.execute_op((address)rs.base(), 0, mtGC);
68
69 _virtual_space = new PSVirtualSpace(rs, page_sz);
70 if (_virtual_space != NULL && _virtual_space->expand_by(bytes)) {
71 _region_start = covered_region.start();
72 _region_size = covered_region.word_size();
73 idx_t* map = (idx_t*)_virtual_space->reserved_low_addr();
74 _beg_bits.set_map(map);
75 _beg_bits.set_size(bits / 2);
76 _end_bits.set_map(map + words / 2);
77 _end_bits.set_size(bits / 2);
78 return true;
79 }
80
81 _region_start = 0;
82 _region_size = 0;
83 if (_virtual_space != NULL) {
84 delete _virtual_space;
85 _virtual_space = NULL;
86 // Release memory reserved in the space.
87 rs.release();
88 }
89 return false;
90 }
91
92 #ifdef ASSERT
93 extern size_t mark_bitmap_count;
94 extern size_t mark_bitmap_size;
95 #endif // #ifdef ASSERT
96
97 bool
98 ParMarkBitMap::mark_obj(HeapWord* addr, size_t size)
99 {
100 const idx_t beg_bit = addr_to_bit(addr);
101 if (_beg_bits.par_set_bit(beg_bit)) {
102 const idx_t end_bit = addr_to_bit(addr + size - 1);
103 bool end_bit_ok = _end_bits.par_set_bit(end_bit);
104 assert(end_bit_ok, "concurrency problem");
105 DEBUG_ONLY(Atomic::inc_ptr(&mark_bitmap_count));
106 DEBUG_ONLY(Atomic::add_ptr(size, &mark_bitmap_size));
107 return true;
108 }
109 return false;
110 }
111
112 size_t
113 ParMarkBitMap::live_words_in_range(HeapWord* beg_addr, HeapWord* end_addr) const
114 {
115 assert(beg_addr <= end_addr, "bad range");
116
117 idx_t live_bits = 0;
118
119 // The bitmap routines require the right boundary to be word-aligned.
120 const idx_t end_bit = addr_to_bit(end_addr);
121 const idx_t range_end = BitMap::word_align_up(end_bit);
122
123 idx_t beg_bit = find_obj_beg(addr_to_bit(beg_addr), range_end);
124 while (beg_bit < end_bit) {
125 idx_t tmp_end = find_obj_end(beg_bit, range_end);
126 if (tmp_end < end_bit) {
127 live_bits += tmp_end - beg_bit + 1;
128 beg_bit = find_obj_beg(tmp_end + 1, range_end);
129 } else {
130 live_bits += end_bit - beg_bit; // No + 1 here; end_bit is not counted.
131 return bits_to_words(live_bits);
132 }
133 }
134 return bits_to_words(live_bits);
135 }
136
137 size_t ParMarkBitMap::live_words_in_range(HeapWord* beg_addr, oop end_obj) const
138 {
139 assert(beg_addr <= (HeapWord*)end_obj, "bad range");
140 assert(is_marked(end_obj), "end_obj must be live");
141
142 idx_t live_bits = 0;
143
144 // The bitmap routines require the right boundary to be word-aligned.
145 const idx_t end_bit = addr_to_bit((HeapWord*)end_obj);
146 const idx_t range_end = BitMap::word_align_up(end_bit);
147
148 idx_t beg_bit = find_obj_beg(addr_to_bit(beg_addr), range_end);
149 while (beg_bit < end_bit) {
150 idx_t tmp_end = find_obj_end(beg_bit, range_end);
151 assert(tmp_end < end_bit, "missing end bit");
152 live_bits += tmp_end - beg_bit + 1;
153 beg_bit = find_obj_beg(tmp_end + 1, range_end);
154 }
155 return bits_to_words(live_bits);
156 }
157
158 ParMarkBitMap::IterationStatus
159 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,
160 idx_t range_beg, idx_t range_end) const
161 {
162 DEBUG_ONLY(verify_bit(range_beg);)
163 DEBUG_ONLY(verify_bit(range_end);)
164 assert(range_beg <= range_end, "live range invalid");
165
166 // The bitmap routines require the right boundary to be word-aligned.
167 const idx_t search_end = BitMap::word_align_up(range_end);
168
169 idx_t cur_beg = find_obj_beg(range_beg, search_end);
170 while (cur_beg < range_end) {
171 const idx_t cur_end = find_obj_end(cur_beg, search_end);
172 if (cur_end >= range_end) {
173 // The obj ends outside the range.
174 live_closure->set_source(bit_to_addr(cur_beg));
175 return incomplete;
176 }
177
178 const size_t size = obj_size(cur_beg, cur_end);
179 IterationStatus status = live_closure->do_addr(bit_to_addr(cur_beg), size);
180 if (status != incomplete) {
181 assert(status == would_overflow || status == full, "sanity");
182 return status;
183 }
184
185 // Successfully processed the object; look for the next object.
186 cur_beg = find_obj_beg(cur_end + 1, search_end);
187 }
188
189 live_closure->set_source(bit_to_addr(range_end));
190 return complete;
191 }
192
193 ParMarkBitMap::IterationStatus
194 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,
195 ParMarkBitMapClosure* dead_closure,
196 idx_t range_beg, idx_t range_end,
197 idx_t dead_range_end) const
198 {
199 DEBUG_ONLY(verify_bit(range_beg);)
200 DEBUG_ONLY(verify_bit(range_end);)
201 DEBUG_ONLY(verify_bit(dead_range_end);)
202 assert(range_beg <= range_end, "live range invalid");
203 assert(range_end <= dead_range_end, "dead range invalid");
204
205 // The bitmap routines require the right boundary to be word-aligned.
206 const idx_t live_search_end = BitMap::word_align_up(range_end);
207 const idx_t dead_search_end = BitMap::word_align_up(dead_range_end);
208
209 idx_t cur_beg = range_beg;
210 if (range_beg < range_end && is_unmarked(range_beg)) {
211 // The range starts with dead space. Look for the next object, then fill.
212 cur_beg = find_obj_beg(range_beg + 1, dead_search_end);
213 const idx_t dead_space_end = MIN2(cur_beg - 1, dead_range_end - 1);
214 const size_t size = obj_size(range_beg, dead_space_end);
215 dead_closure->do_addr(bit_to_addr(range_beg), size);
216 }
217
218 while (cur_beg < range_end) {
219 const idx_t cur_end = find_obj_end(cur_beg, live_search_end);
220 if (cur_end >= range_end) {
221 // The obj ends outside the range.
222 live_closure->set_source(bit_to_addr(cur_beg));
223 return incomplete;
224 }
225
226 const size_t size = obj_size(cur_beg, cur_end);
227 IterationStatus status = live_closure->do_addr(bit_to_addr(cur_beg), size);
228 if (status != incomplete) {
229 assert(status == would_overflow || status == full, "sanity");
230 return status;
231 }
232
233 // Look for the start of the next object.
234 const idx_t dead_space_beg = cur_end + 1;
235 cur_beg = find_obj_beg(dead_space_beg, dead_search_end);
236 if (cur_beg > dead_space_beg) {
237 // Found dead space; compute the size and invoke the dead closure.
238 const idx_t dead_space_end = MIN2(cur_beg - 1, dead_range_end - 1);
239 const size_t size = obj_size(dead_space_beg, dead_space_end);
240 dead_closure->do_addr(bit_to_addr(dead_space_beg), size);
241 }
242 }
243
244 live_closure->set_source(bit_to_addr(range_end));
245 return complete;
246 }
247
248 #ifndef PRODUCT
249 void ParMarkBitMap::reset_counters()
250 {
251 _cas_tries = _cas_retries = _cas_by_another = 0;
252 }
253 #endif // #ifndef PRODUCT
254
255 #ifdef ASSERT
256 void ParMarkBitMap::verify_clear() const
257 {
258 const idx_t* const beg = (const idx_t*)_virtual_space->committed_low_addr();
259 const idx_t* const end = (const idx_t*)_virtual_space->committed_high_addr();
260 for (const idx_t* p = beg; p < end; ++p) {
261 assert(*p == 0, "bitmap not clear");
262 }
263 }
264 #endif // #ifdef ASSERT