1 /*
2 * Copyright (c) 2005, 2008, 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 "incls/_precompiled.incl"
26 # include "incls/_parMarkBitMap.cpp.incl"
27
28 bool
29 ParMarkBitMap::initialize(MemRegion covered_region)
30 {
31 const idx_t bits = bits_required(covered_region);
32 // The bits will be divided evenly between two bitmaps; each of them should be
33 // an integral number of words.
34 assert(bits % (BitsPerWord * 2) == 0, "region size unaligned");
35
36 const size_t words = bits / BitsPerWord;
37 const size_t raw_bytes = words * sizeof(idx_t);
38 const size_t page_sz = os::page_size_for_region(raw_bytes, raw_bytes, 10);
39 const size_t granularity = os::vm_allocation_granularity();
40 const size_t bytes = align_size_up(raw_bytes, MAX2(page_sz, granularity));
41
42 const size_t rs_align = page_sz == (size_t) os::vm_page_size() ? 0 :
43 MAX2(page_sz, granularity);
44 ReservedSpace rs(bytes, rs_align, rs_align > 0);
45 os::trace_page_sizes("par bitmap", raw_bytes, raw_bytes, page_sz,
46 rs.base(), rs.size());
47 _virtual_space = new PSVirtualSpace(rs, page_sz);
48 if (_virtual_space != NULL && _virtual_space->expand_by(bytes)) {
49 _region_start = covered_region.start();
50 _region_size = covered_region.word_size();
51 idx_t* map = (idx_t*)_virtual_space->reserved_low_addr();
52 _beg_bits.set_map(map);
53 _beg_bits.set_size(bits / 2);
54 _end_bits.set_map(map + words / 2);
55 _end_bits.set_size(bits / 2);
56 return true;
57 }
58
59 _region_start = 0;
60 _region_size = 0;
61 if (_virtual_space != NULL) {
62 delete _virtual_space;
63 _virtual_space = NULL;
64 // Release memory reserved in the space.
65 rs.release();
66 }
67 return false;
68 }
69
70 #ifdef ASSERT
71 extern size_t mark_bitmap_count;
72 extern size_t mark_bitmap_size;
73 #endif // #ifdef ASSERT
74
75 bool
76 ParMarkBitMap::mark_obj(HeapWord* addr, size_t size)
77 {
78 const idx_t beg_bit = addr_to_bit(addr);
79 if (_beg_bits.par_set_bit(beg_bit)) {
80 const idx_t end_bit = addr_to_bit(addr + size - 1);
81 bool end_bit_ok = _end_bits.par_set_bit(end_bit);
82 assert(end_bit_ok, "concurrency problem");
83 DEBUG_ONLY(Atomic::inc_ptr(&mark_bitmap_count));
84 DEBUG_ONLY(Atomic::add_ptr(size, &mark_bitmap_size));
85 return true;
86 }
87 return false;
88 }
89
90 size_t
91 ParMarkBitMap::live_words_in_range(HeapWord* beg_addr, HeapWord* end_addr) const
92 {
93 assert(beg_addr <= end_addr, "bad range");
94
95 idx_t live_bits = 0;
96
97 // The bitmap routines require the right boundary to be word-aligned.
98 const idx_t end_bit = addr_to_bit(end_addr);
99 const idx_t range_end = BitMap::word_align_up(end_bit);
100
101 idx_t beg_bit = find_obj_beg(addr_to_bit(beg_addr), range_end);
102 while (beg_bit < end_bit) {
103 idx_t tmp_end = find_obj_end(beg_bit, range_end);
104 if (tmp_end < end_bit) {
105 live_bits += tmp_end - beg_bit + 1;
106 beg_bit = find_obj_beg(tmp_end + 1, range_end);
107 } else {
108 live_bits += end_bit - beg_bit; // No + 1 here; end_bit is not counted.
109 return bits_to_words(live_bits);
110 }
111 }
112 return bits_to_words(live_bits);
113 }
114
115 size_t ParMarkBitMap::live_words_in_range(HeapWord* beg_addr, oop end_obj) const
116 {
117 assert(beg_addr <= (HeapWord*)end_obj, "bad range");
118 assert(is_marked(end_obj), "end_obj must be live");
119
120 idx_t live_bits = 0;
121
122 // The bitmap routines require the right boundary to be word-aligned.
123 const idx_t end_bit = addr_to_bit((HeapWord*)end_obj);
124 const idx_t range_end = BitMap::word_align_up(end_bit);
125
126 idx_t beg_bit = find_obj_beg(addr_to_bit(beg_addr), range_end);
127 while (beg_bit < end_bit) {
128 idx_t tmp_end = find_obj_end(beg_bit, range_end);
129 assert(tmp_end < end_bit, "missing end bit");
130 live_bits += tmp_end - beg_bit + 1;
131 beg_bit = find_obj_beg(tmp_end + 1, range_end);
132 }
133 return bits_to_words(live_bits);
134 }
135
136 ParMarkBitMap::IterationStatus
137 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,
138 idx_t range_beg, idx_t range_end) const
139 {
140 DEBUG_ONLY(verify_bit(range_beg);)
141 DEBUG_ONLY(verify_bit(range_end);)
142 assert(range_beg <= range_end, "live range invalid");
143
144 // The bitmap routines require the right boundary to be word-aligned.
145 const idx_t search_end = BitMap::word_align_up(range_end);
146
147 idx_t cur_beg = find_obj_beg(range_beg, search_end);
148 while (cur_beg < range_end) {
149 const idx_t cur_end = find_obj_end(cur_beg, search_end);
150 if (cur_end >= range_end) {
151 // The obj ends outside the range.
152 live_closure->set_source(bit_to_addr(cur_beg));
153 return incomplete;
154 }
155
156 const size_t size = obj_size(cur_beg, cur_end);
157 IterationStatus status = live_closure->do_addr(bit_to_addr(cur_beg), size);
158 if (status != incomplete) {
159 assert(status == would_overflow || status == full, "sanity");
160 return status;
161 }
162
163 // Successfully processed the object; look for the next object.
164 cur_beg = find_obj_beg(cur_end + 1, search_end);
165 }
166
167 live_closure->set_source(bit_to_addr(range_end));
168 return complete;
169 }
170
171 ParMarkBitMap::IterationStatus
172 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,
173 ParMarkBitMapClosure* dead_closure,
174 idx_t range_beg, idx_t range_end,
175 idx_t dead_range_end) const
176 {
177 DEBUG_ONLY(verify_bit(range_beg);)
178 DEBUG_ONLY(verify_bit(range_end);)
179 DEBUG_ONLY(verify_bit(dead_range_end);)
180 assert(range_beg <= range_end, "live range invalid");
181 assert(range_end <= dead_range_end, "dead range invalid");
182
183 // The bitmap routines require the right boundary to be word-aligned.
184 const idx_t live_search_end = BitMap::word_align_up(range_end);
185 const idx_t dead_search_end = BitMap::word_align_up(dead_range_end);
186
187 idx_t cur_beg = range_beg;
188 if (range_beg < range_end && is_unmarked(range_beg)) {
189 // The range starts with dead space. Look for the next object, then fill.
190 cur_beg = find_obj_beg(range_beg + 1, dead_search_end);
191 const idx_t dead_space_end = MIN2(cur_beg - 1, dead_range_end - 1);
192 const size_t size = obj_size(range_beg, dead_space_end);
193 dead_closure->do_addr(bit_to_addr(range_beg), size);
194 }
195
196 while (cur_beg < range_end) {
197 const idx_t cur_end = find_obj_end(cur_beg, live_search_end);
198 if (cur_end >= range_end) {
199 // The obj ends outside the range.
200 live_closure->set_source(bit_to_addr(cur_beg));
201 return incomplete;
202 }
203
204 const size_t size = obj_size(cur_beg, cur_end);
205 IterationStatus status = live_closure->do_addr(bit_to_addr(cur_beg), size);
206 if (status != incomplete) {
207 assert(status == would_overflow || status == full, "sanity");
208 return status;
209 }
210
211 // Look for the start of the next object.
212 const idx_t dead_space_beg = cur_end + 1;
213 cur_beg = find_obj_beg(dead_space_beg, dead_search_end);
214 if (cur_beg > dead_space_beg) {
215 // Found dead space; compute the size and invoke the dead closure.
216 const idx_t dead_space_end = MIN2(cur_beg - 1, dead_range_end - 1);
217 const size_t size = obj_size(dead_space_beg, dead_space_end);
218 dead_closure->do_addr(bit_to_addr(dead_space_beg), size);
219 }
220 }
221
222 live_closure->set_source(bit_to_addr(range_end));
223 return complete;
224 }
225
226 #ifndef PRODUCT
227 void ParMarkBitMap::reset_counters()
228 {
229 _cas_tries = _cas_retries = _cas_by_another = 0;
230 }
231 #endif // #ifndef PRODUCT
232
233 #ifdef ASSERT
234 void ParMarkBitMap::verify_clear() const
235 {
236 const idx_t* const beg = (const idx_t*)_virtual_space->committed_low_addr();
237 const idx_t* const end = (const idx_t*)_virtual_space->committed_high_addr();
238 for (const idx_t* p = beg; p < end; ++p) {
239 assert(*p == 0, "bitmap not clear");
240 }
241 }
242 #endif // #ifdef ASSERT