1 #ifdef USE_PRAGMA_IDENT_SRC
2 #pragma ident "@(#)parMarkBitMap.cpp 1.31 07/10/04 10:49:33 JVM"
3 #endif
4 /*
5 * Copyright 2005-2006 Sun Microsystems, Inc. All Rights Reserved.
6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
7 *
8 * This code is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 only, as
10 * published by the Free Software Foundation.
11 *
12 * This code is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 * version 2 for more details (a copy is included in the LICENSE file that
16 * accompanied this code).
17 *
18 * You should have received a copy of the GNU General Public License version
19 * 2 along with this work; if not, write to the Free Software Foundation,
20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
21 *
22 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
23 * CA 95054 USA or visit www.sun.com if you need additional information or
24 * have any questions.
25 *
26 */
27
28 # include "incls/_precompiled.incl"
29 # include "incls/_parMarkBitMap.cpp.incl"
30
31 bool
32 ParMarkBitMap::initialize(MemRegion covered_region)
33 {
34 const idx_t bits = bits_required(covered_region);
35 // The bits will be divided evenly between two bitmaps; each of them should be
36 // an integral number of words.
37 assert(bits % (BitsPerWord * 2) == 0, "region size unaligned");
38
39 const size_t words = bits / BitsPerWord;
40 const size_t raw_bytes = words * sizeof(idx_t);
41 const size_t page_sz = os::page_size_for_region(raw_bytes, raw_bytes, 10);
42 const size_t granularity = os::vm_allocation_granularity();
43 const size_t bytes = align_size_up(raw_bytes, MAX2(page_sz, granularity));
44
45 const size_t rs_align = page_sz == (size_t) os::vm_page_size() ? 0 :
46 MAX2(page_sz, granularity);
47 ReservedSpace rs(bytes, rs_align, false);
48 os::trace_page_sizes("par bitmap", raw_bytes, raw_bytes, page_sz,
49 rs.base(), rs.size());
50 _virtual_space = new PSVirtualSpace(rs, page_sz);
51 if (_virtual_space != NULL && _virtual_space->expand_by(bytes)) {
52 _region_start = covered_region.start();
53 _region_size = covered_region.word_size();
54 idx_t* map = (idx_t*)_virtual_space->reserved_low_addr();
55 _beg_bits.set_map(map);
56 _beg_bits.set_size(bits / 2);
57 _end_bits.set_map(map + words / 2);
58 _end_bits.set_size(bits / 2);
59 return true;
60 }
61
62 _region_start = 0;
63 _region_size = 0;
64 if (_virtual_space != NULL) {
65 delete _virtual_space;
66 _virtual_space = NULL;
67 }
68 return false;
69 }
70
71 #ifdef ASSERT
72 extern size_t mark_bitmap_count;
73 extern size_t mark_bitmap_size;
74 #endif // #ifdef ASSERT
75
76 bool
77 ParMarkBitMap::mark_obj(HeapWord* addr, size_t size)
78 {
79 const idx_t beg_bit = addr_to_bit(addr);
80 if (_beg_bits.par_set_bit(beg_bit)) {
81 const idx_t end_bit = addr_to_bit(addr + size - 1);
82 bool end_bit_ok = _end_bits.par_set_bit(end_bit);
83 assert(end_bit_ok, "concurrency problem");
84 DEBUG_ONLY(Atomic::inc_ptr(&mark_bitmap_count));
85 DEBUG_ONLY(Atomic::add_ptr(size, &mark_bitmap_size));
86 return true;
87 }
88 return false;
89 }
90
91 size_t
92 ParMarkBitMap::live_words_in_range(HeapWord* beg_addr, HeapWord* end_addr) const
93 {
94 assert(beg_addr <= end_addr, "bad range");
95
96 idx_t live_bits = 0;
97
98 // The bitmap routines require the right boundary to be word-aligned.
99 const idx_t end_bit = addr_to_bit(end_addr);
100 const idx_t range_end = BitMap::word_align_up(end_bit);
101
102 idx_t beg_bit = find_obj_beg(addr_to_bit(beg_addr), range_end);
103 while (beg_bit < end_bit) {
104 idx_t tmp_end = find_obj_end(beg_bit, range_end);
105 if (tmp_end < end_bit) {
106 live_bits += tmp_end - beg_bit + 1;
107 beg_bit = find_obj_beg(tmp_end + 1, range_end);
108 } else {
109 live_bits += end_bit - beg_bit; // No + 1 here; end_bit is not counted.
110 return bits_to_words(live_bits);
111 }
112 }
113 return bits_to_words(live_bits);
114 }
115
116 size_t ParMarkBitMap::live_words_in_range(HeapWord* beg_addr, oop end_obj) const
117 {
118 assert(beg_addr <= (HeapWord*)end_obj, "bad range");
119 assert(is_marked(end_obj), "end_obj must be live");
120
121 idx_t live_bits = 0;
122
123 // The bitmap routines require the right boundary to be word-aligned.
124 const idx_t end_bit = addr_to_bit((HeapWord*)end_obj);
125 const idx_t range_end = BitMap::word_align_up(end_bit);
126
127 idx_t beg_bit = find_obj_beg(addr_to_bit(beg_addr), range_end);
128 while (beg_bit < end_bit) {
129 idx_t tmp_end = find_obj_end(beg_bit, range_end);
130 assert(tmp_end < end_bit, "missing end bit");
131 live_bits += tmp_end - beg_bit + 1;
132 beg_bit = find_obj_beg(tmp_end + 1, range_end);
133 }
134 return bits_to_words(live_bits);
135 }
136
137 ParMarkBitMap::IterationStatus
138 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,
139 idx_t range_beg, idx_t range_end) const
140 {
141 DEBUG_ONLY(verify_bit(range_beg);)
142 DEBUG_ONLY(verify_bit(range_end);)
143 assert(range_beg <= range_end, "live range invalid");
144
145 // The bitmap routines require the right boundary to be word-aligned.
146 const idx_t search_end = BitMap::word_align_up(range_end);
147
148 idx_t cur_beg = find_obj_beg(range_beg, search_end);
149 while (cur_beg < range_end) {
150 const idx_t cur_end = find_obj_end(cur_beg, search_end);
151 if (cur_end >= range_end) {
152 // The obj ends outside the range.
153 live_closure->set_source(bit_to_addr(cur_beg));
154 return incomplete;
155 }
156
157 const size_t size = obj_size(cur_beg, cur_end);
158 IterationStatus status = live_closure->do_addr(bit_to_addr(cur_beg), size);
159 if (status != incomplete) {
160 assert(status == would_overflow || status == full, "sanity");
161 return status;
162 }
163
164 // Successfully processed the object; look for the next object.
165 cur_beg = find_obj_beg(cur_end + 1, search_end);
166 }
167
168 live_closure->set_source(bit_to_addr(range_end));
169 return complete;
170 }
171
172 ParMarkBitMap::IterationStatus
173 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,
174 ParMarkBitMapClosure* dead_closure,
175 idx_t range_beg, idx_t range_end,
176 idx_t dead_range_end) const
177 {
178 DEBUG_ONLY(verify_bit(range_beg);)
179 DEBUG_ONLY(verify_bit(range_end);)
180 DEBUG_ONLY(verify_bit(dead_range_end);)
181 assert(range_beg <= range_end, "live range invalid");
182 assert(range_end <= dead_range_end, "dead range invalid");
183
184 // The bitmap routines require the right boundary to be word-aligned.
185 const idx_t live_search_end = BitMap::word_align_up(range_end);
186 const idx_t dead_search_end = BitMap::word_align_up(dead_range_end);
187
188 idx_t cur_beg = range_beg;
189 if (range_beg < range_end && is_unmarked(range_beg)) {
190 // The range starts with dead space. Look for the next object, then fill.
191 cur_beg = find_obj_beg(range_beg + 1, dead_search_end);
192 const idx_t dead_space_end = MIN2(cur_beg - 1, dead_range_end - 1);
193 const size_t size = obj_size(range_beg, dead_space_end);
194 dead_closure->do_addr(bit_to_addr(range_beg), size);
195 }
196
197 while (cur_beg < range_end) {
198 const idx_t cur_end = find_obj_end(cur_beg, live_search_end);
199 if (cur_end >= range_end) {
200 // The obj ends outside the range.
201 live_closure->set_source(bit_to_addr(cur_beg));
202 return incomplete;
203 }
204
205 const size_t size = obj_size(cur_beg, cur_end);
206 IterationStatus status = live_closure->do_addr(bit_to_addr(cur_beg), size);
207 if (status != incomplete) {
208 assert(status == would_overflow || status == full, "sanity");
209 return status;
210 }
211
212 // Look for the start of the next object.
213 const idx_t dead_space_beg = cur_end + 1;
214 cur_beg = find_obj_beg(dead_space_beg, dead_search_end);
215 if (cur_beg > dead_space_beg) {
216 // Found dead space; compute the size and invoke the dead closure.
217 const idx_t dead_space_end = MIN2(cur_beg - 1, dead_range_end - 1);
218 const size_t size = obj_size(dead_space_beg, dead_space_end);
219 dead_closure->do_addr(bit_to_addr(dead_space_beg), size);
220 }
221 }
222
223 live_closure->set_source(bit_to_addr(range_end));
224 return complete;
225 }
226
227 #ifndef PRODUCT
228 void ParMarkBitMap::reset_counters()
229 {
230 _cas_tries = _cas_retries = _cas_by_another = 0;
231 }
232 #endif // #ifndef PRODUCT
233
234 #ifdef ASSERT
235 void ParMarkBitMap::verify_clear() const
236 {
237 const idx_t* const beg = (const idx_t*)_virtual_space->committed_low_addr();
238 const idx_t* const end = (const idx_t*)_virtual_space->committed_high_addr();
239 for (const idx_t* p = beg; p < end; ++p) {
240 assert(*p == 0, "bitmap not clear");
241 }
242 }
243 #endif // #ifdef ASSERT