1 /*
2 * Copyright (c) 2005, 2012, 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 MemTracker::record_virtual_memory_type((address)rs.base(), mtGC);
67
68 _virtual_space = new PSVirtualSpace(rs, page_sz);
69 if (_virtual_space != NULL && _virtual_space->expand_by(bytes)) {
70 _region_start = covered_region.start();
71 _region_size = covered_region.word_size();
72 idx_t* map = (idx_t*)_virtual_space->reserved_low_addr();
73 _beg_bits.set_map(map);
74 _beg_bits.set_size(bits / 2);
75 _end_bits.set_map(map + words / 2);
76 _end_bits.set_size(bits / 2);
77 return true;
78 }
79
80 _region_start = 0;
81 _region_size = 0;
82 if (_virtual_space != NULL) {
83 delete _virtual_space;
84 _virtual_space = NULL;
85 // Release memory reserved in the space.
86 rs.release();
87 }
88 return false;
89 }
90
91 #ifdef ASSERT
92 extern size_t mark_bitmap_count;
93 extern size_t mark_bitmap_size;
94 #endif // #ifdef ASSERT
95
96 bool
97 ParMarkBitMap::mark_obj(HeapWord* addr, size_t size)
98 {
99 const idx_t beg_bit = addr_to_bit(addr);
100 if (_beg_bits.par_set_bit(beg_bit)) {
101 const idx_t end_bit = addr_to_bit(addr + size - 1);
102 bool end_bit_ok = _end_bits.par_set_bit(end_bit);
103 assert(end_bit_ok, "concurrency problem");
104 DEBUG_ONLY(Atomic::inc_ptr(&mark_bitmap_count));
105 DEBUG_ONLY(Atomic::add_ptr(size, &mark_bitmap_size));
106 return true;
107 }
108 return false;
109 }
110
111 size_t
112 ParMarkBitMap::live_words_in_range(HeapWord* beg_addr, HeapWord* end_addr) const
113 {
114 assert(beg_addr <= end_addr, "bad range");
115
116 idx_t live_bits = 0;
117
118 // The bitmap routines require the right boundary to be word-aligned.
119 const idx_t end_bit = addr_to_bit(end_addr);
120 const idx_t range_end = BitMap::word_align_up(end_bit);
121
122 idx_t beg_bit = find_obj_beg(addr_to_bit(beg_addr), range_end);
123 while (beg_bit < end_bit) {
124 idx_t tmp_end = find_obj_end(beg_bit, range_end);
125 if (tmp_end < end_bit) {
126 live_bits += tmp_end - beg_bit + 1;
127 beg_bit = find_obj_beg(tmp_end + 1, range_end);
128 } else {
129 live_bits += end_bit - beg_bit; // No + 1 here; end_bit is not counted.
130 return bits_to_words(live_bits);
131 }
132 }
133 return bits_to_words(live_bits);
134 }
135
136 size_t ParMarkBitMap::live_words_in_range(HeapWord* beg_addr, oop end_obj) const
137 {
138 assert(beg_addr <= (HeapWord*)end_obj, "bad range");
139 assert(is_marked(end_obj), "end_obj must be live");
140
141 idx_t live_bits = 0;
142
143 // The bitmap routines require the right boundary to be word-aligned.
144 const idx_t end_bit = addr_to_bit((HeapWord*)end_obj);
145 const idx_t range_end = BitMap::word_align_up(end_bit);
146
147 idx_t beg_bit = find_obj_beg(addr_to_bit(beg_addr), range_end);
148 while (beg_bit < end_bit) {
149 idx_t tmp_end = find_obj_end(beg_bit, range_end);
150 assert(tmp_end < end_bit, "missing end bit");
151 live_bits += tmp_end - beg_bit + 1;
152 beg_bit = find_obj_beg(tmp_end + 1, range_end);
153 }
154 return bits_to_words(live_bits);
155 }
156
157 ParMarkBitMap::IterationStatus
158 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,
159 idx_t range_beg, idx_t range_end) const
160 {
161 DEBUG_ONLY(verify_bit(range_beg);)
162 DEBUG_ONLY(verify_bit(range_end);)
163 assert(range_beg <= range_end, "live range invalid");
164
165 // The bitmap routines require the right boundary to be word-aligned.
166 const idx_t search_end = BitMap::word_align_up(range_end);
167
168 idx_t cur_beg = find_obj_beg(range_beg, search_end);
169 while (cur_beg < range_end) {
170 const idx_t cur_end = find_obj_end(cur_beg, search_end);
171 if (cur_end >= range_end) {
172 // The obj ends outside the range.
173 live_closure->set_source(bit_to_addr(cur_beg));
174 return incomplete;
175 }
176
177 const size_t size = obj_size(cur_beg, cur_end);
178 IterationStatus status = live_closure->do_addr(bit_to_addr(cur_beg), size);
179 if (status != incomplete) {
180 assert(status == would_overflow || status == full, "sanity");
181 return status;
182 }
183
184 // Successfully processed the object; look for the next object.
185 cur_beg = find_obj_beg(cur_end + 1, search_end);
186 }
187
188 live_closure->set_source(bit_to_addr(range_end));
189 return complete;
190 }
191
192 ParMarkBitMap::IterationStatus
193 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,
194 ParMarkBitMapClosure* dead_closure,
195 idx_t range_beg, idx_t range_end,
196 idx_t dead_range_end) const
197 {
198 DEBUG_ONLY(verify_bit(range_beg);)
199 DEBUG_ONLY(verify_bit(range_end);)
200 DEBUG_ONLY(verify_bit(dead_range_end);)
201 assert(range_beg <= range_end, "live range invalid");
202 assert(range_end <= dead_range_end, "dead range invalid");
203
204 // The bitmap routines require the right boundary to be word-aligned.
205 const idx_t live_search_end = BitMap::word_align_up(range_end);
206 const idx_t dead_search_end = BitMap::word_align_up(dead_range_end);
207
208 idx_t cur_beg = range_beg;
209 if (range_beg < range_end && is_unmarked(range_beg)) {
210 // The range starts with dead space. Look for the next object, then fill.
211 cur_beg = find_obj_beg(range_beg + 1, dead_search_end);
212 const idx_t dead_space_end = MIN2(cur_beg - 1, dead_range_end - 1);
213 const size_t size = obj_size(range_beg, dead_space_end);
214 dead_closure->do_addr(bit_to_addr(range_beg), size);
215 }
216
217 while (cur_beg < range_end) {
218 const idx_t cur_end = find_obj_end(cur_beg, live_search_end);
219 if (cur_end >= range_end) {
220 // The obj ends outside the range.
221 live_closure->set_source(bit_to_addr(cur_beg));
222 return incomplete;
223 }
224
225 const size_t size = obj_size(cur_beg, cur_end);
226 IterationStatus status = live_closure->do_addr(bit_to_addr(cur_beg), size);
227 if (status != incomplete) {
228 assert(status == would_overflow || status == full, "sanity");
229 return status;
230 }
231
232 // Look for the start of the next object.
233 const idx_t dead_space_beg = cur_end + 1;
234 cur_beg = find_obj_beg(dead_space_beg, dead_search_end);
235 if (cur_beg > dead_space_beg) {
236 // Found dead space; compute the size and invoke the dead closure.
237 const idx_t dead_space_end = MIN2(cur_beg - 1, dead_range_end - 1);
238 const size_t size = obj_size(dead_space_beg, dead_space_end);
239 dead_closure->do_addr(bit_to_addr(dead_space_beg), size);
240 }
241 }
242
243 live_closure->set_source(bit_to_addr(range_end));
244 return complete;
245 }
246
247 #ifndef PRODUCT
248 void ParMarkBitMap::reset_counters()
249 {
250 _cas_tries = _cas_retries = _cas_by_another = 0;
251 }
252 #endif // #ifndef PRODUCT
253
254 #ifdef ASSERT
255 void ParMarkBitMap::verify_clear() const
256 {
257 const idx_t* const beg = (const idx_t*)_virtual_space->committed_low_addr();
258 const idx_t* const end = (const idx_t*)_virtual_space->committed_high_addr();
259 for (const idx_t* p = beg; p < end; ++p) {
260 assert(*p == 0, "bitmap not clear");
261 }
262 }
263 #endif // #ifdef ASSERT