1 /*
2 * Copyright (c) 2005, 2016, 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/parallel/parMarkBitMap.hpp"
27 #include "gc/parallel/psCompactionManager.inline.hpp"
28 #include "gc/parallel/psParallelCompact.inline.hpp"
29 #include "oops/oop.inline.hpp"
30 #include "runtime/atomic.inline.hpp"
31 #include "runtime/os.hpp"
32 #include "services/memTracker.hpp"
33 #include "utilities/bitMap.inline.hpp"
34
35 bool
36 ParMarkBitMap::initialize(MemRegion covered_region)
37 {
38 const idx_t bits = bits_required(covered_region);
39 // The bits will be divided evenly between two bitmaps; each of them should be
40 // an integral number of words.
41 assert(bits % (BitsPerWord * 2) == 0, "region size unaligned");
42
43 const size_t words = bits / BitsPerWord;
44 const size_t raw_bytes = words * sizeof(idx_t);
45 const size_t page_sz = os::page_size_for_region_aligned(raw_bytes, 10);
46 const size_t granularity = os::vm_allocation_granularity();
47 _reserved_byte_size = align_size_up(raw_bytes, MAX2(page_sz, granularity));
48
49 const size_t rs_align = page_sz == (size_t) os::vm_page_size() ? 0 :
50 MAX2(page_sz, granularity);
51 ReservedSpace rs(_reserved_byte_size, rs_align, rs_align > 0);
52 os::trace_page_sizes("par bitmap", raw_bytes, raw_bytes, page_sz,
53 rs.base(), rs.size());
54
55 MemTracker::record_virtual_memory_type((address)rs.base(), mtGC);
56
57 _virtual_space = new PSVirtualSpace(rs, page_sz);
58 if (_virtual_space != NULL && _virtual_space->expand_by(_reserved_byte_size)) {
59 _region_start = covered_region.start();
60 _region_size = covered_region.word_size();
61 BitMap::bm_word_t* map = (BitMap::bm_word_t*)_virtual_space->reserved_low_addr();
62 _beg_bits.set_map(map);
63 _beg_bits.set_size(bits / 2);
64 _end_bits.set_map(map + words / 2);
65 _end_bits.set_size(bits / 2);
66 return true;
67 }
68
69 _region_start = 0;
70 _region_size = 0;
71 if (_virtual_space != NULL) {
72 delete _virtual_space;
73 _virtual_space = NULL;
74 // Release memory reserved in the space.
75 rs.release();
76 }
77 return false;
78 }
79
80 #ifdef ASSERT
81 extern size_t mark_bitmap_count;
82 extern size_t mark_bitmap_size;
83 #endif // #ifdef ASSERT
84
85 bool
86 ParMarkBitMap::mark_obj(HeapWord* addr, size_t size)
87 {
88 const idx_t beg_bit = addr_to_bit(addr);
89 if (_beg_bits.par_set_bit(beg_bit)) {
90 const idx_t end_bit = addr_to_bit(addr + size - 1);
91 bool end_bit_ok = _end_bits.par_set_bit(end_bit);
92 assert(end_bit_ok, "concurrency problem");
93 DEBUG_ONLY(Atomic::inc_ptr(&mark_bitmap_count));
94 DEBUG_ONLY(Atomic::add_ptr(size, &mark_bitmap_size));
95 return true;
96 }
97 return false;
98 }
99
100 inline bool
101 ParMarkBitMap::is_live_words_in_range_in_cache(ParCompactionManager* cm, HeapWord* beg_addr) const {
102 return cm->last_query_begin() == beg_addr;
103 }
104
105 inline void
106 ParMarkBitMap::update_live_words_in_range_cache(ParCompactionManager* cm, HeapWord* beg_addr, oop end_obj, size_t result) const {
107 cm->set_last_query_begin(beg_addr);
108 cm->set_last_query_object(end_obj);
109 cm->set_last_query_return(result);
110 }
111
112 size_t
113 ParMarkBitMap::live_words_in_range_helper(HeapWord* beg_addr, oop end_obj) const
114 {
115 assert(beg_addr <= (HeapWord*)end_obj, "bad range");
116 assert(is_marked(end_obj), "end_obj must be live");
117
118 idx_t live_bits = 0;
119
120 // The bitmap routines require the right boundary to be word-aligned.
121 const idx_t end_bit = addr_to_bit((HeapWord*)end_obj);
122 const idx_t range_end = BitMap::word_align_up(end_bit);
123
124 idx_t beg_bit = find_obj_beg(addr_to_bit(beg_addr), range_end);
125 while (beg_bit < end_bit) {
126 idx_t tmp_end = find_obj_end(beg_bit, range_end);
127 assert(tmp_end < end_bit, "missing end bit");
128 live_bits += tmp_end - beg_bit + 1;
129 beg_bit = find_obj_beg(tmp_end + 1, range_end);
130 }
131 return bits_to_words(live_bits);
132 }
133
134 size_t
135 ParMarkBitMap::live_words_in_range_use_cache(ParCompactionManager* cm, HeapWord* beg_addr, oop end_obj) const
136 {
137 HeapWord* last_beg = cm->last_query_begin();
138 oop last_obj = cm->last_query_object();
139 size_t last_ret = cm->last_query_return();
140 if (end_obj > last_obj) {
141 last_ret = last_ret + live_words_in_range_helper((HeapWord*)last_obj, end_obj);
142 last_obj = end_obj;
143 } else if (end_obj < last_obj) {
144 // The cached value is for an object that is to the left (lower address) of the current
145 // end_obj. Calculate back from that cached value.
146 if (pointer_delta((HeapWord*)end_obj, (HeapWord*)beg_addr) > pointer_delta((HeapWord*)last_obj, (HeapWord*)end_obj)) {
147 last_ret = last_ret - live_words_in_range_helper((HeapWord*)end_obj, last_obj);
148 } else {
149 last_ret = live_words_in_range_helper(beg_addr, end_obj);
150 }
151 last_obj = end_obj;
152 }
153
154 update_live_words_in_range_cache(cm, last_beg, last_obj, last_ret);
155 return last_ret;
156 }
157
158 size_t
159 ParMarkBitMap::live_words_in_range(ParCompactionManager* cm, HeapWord* beg_addr, oop end_obj) const
160 {
161 // Try to reuse result from ParCompactionManager cache first.
162 if (is_live_words_in_range_in_cache(cm, beg_addr)) {
163 return live_words_in_range_use_cache(cm, beg_addr, end_obj);
164 }
165 size_t ret = live_words_in_range_helper(beg_addr, end_obj);
166 update_live_words_in_range_cache(cm, beg_addr, end_obj, ret);
167 return ret;
168 }
169
170 ParMarkBitMap::IterationStatus
171 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,
172 idx_t range_beg, idx_t range_end) const
173 {
174 DEBUG_ONLY(verify_bit(range_beg);)
175 DEBUG_ONLY(verify_bit(range_end);)
176 assert(range_beg <= range_end, "live range invalid");
177
178 // The bitmap routines require the right boundary to be word-aligned.
179 const idx_t search_end = BitMap::word_align_up(range_end);
180
181 idx_t cur_beg = find_obj_beg(range_beg, search_end);
182 while (cur_beg < range_end) {
183 const idx_t cur_end = find_obj_end(cur_beg, search_end);
184 if (cur_end >= range_end) {
185 // The obj ends outside the range.
186 live_closure->set_source(bit_to_addr(cur_beg));
187 return incomplete;
188 }
189
190 const size_t size = obj_size(cur_beg, cur_end);
191 IterationStatus status = live_closure->do_addr(bit_to_addr(cur_beg), size);
192 if (status != incomplete) {
193 assert(status == would_overflow || status == full, "sanity");
194 return status;
195 }
196
197 // Successfully processed the object; look for the next object.
198 cur_beg = find_obj_beg(cur_end + 1, search_end);
199 }
200
201 live_closure->set_source(bit_to_addr(range_end));
202 return complete;
203 }
204
205 ParMarkBitMap::IterationStatus
206 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,
207 ParMarkBitMapClosure* dead_closure,
208 idx_t range_beg, idx_t range_end,
209 idx_t dead_range_end) const
210 {
211 DEBUG_ONLY(verify_bit(range_beg);)
212 DEBUG_ONLY(verify_bit(range_end);)
213 DEBUG_ONLY(verify_bit(dead_range_end);)
214 assert(range_beg <= range_end, "live range invalid");
215 assert(range_end <= dead_range_end, "dead range invalid");
216
217 // The bitmap routines require the right boundary to be word-aligned.
218 const idx_t live_search_end = BitMap::word_align_up(range_end);
219 const idx_t dead_search_end = BitMap::word_align_up(dead_range_end);
220
221 idx_t cur_beg = range_beg;
222 if (range_beg < range_end && is_unmarked(range_beg)) {
223 // The range starts with dead space. Look for the next object, then fill.
224 cur_beg = find_obj_beg(range_beg + 1, dead_search_end);
225 const idx_t dead_space_end = MIN2(cur_beg - 1, dead_range_end - 1);
226 const size_t size = obj_size(range_beg, dead_space_end);
227 dead_closure->do_addr(bit_to_addr(range_beg), size);
228 }
229
230 while (cur_beg < range_end) {
231 const idx_t cur_end = find_obj_end(cur_beg, live_search_end);
232 if (cur_end >= range_end) {
233 // The obj ends outside the range.
234 live_closure->set_source(bit_to_addr(cur_beg));
235 return incomplete;
236 }
237
238 const size_t size = obj_size(cur_beg, cur_end);
239 IterationStatus status = live_closure->do_addr(bit_to_addr(cur_beg), size);
240 if (status != incomplete) {
241 assert(status == would_overflow || status == full, "sanity");
242 return status;
243 }
244
245 // Look for the start of the next object.
246 const idx_t dead_space_beg = cur_end + 1;
247 cur_beg = find_obj_beg(dead_space_beg, dead_search_end);
248 if (cur_beg > dead_space_beg) {
249 // Found dead space; compute the size and invoke the dead closure.
250 const idx_t dead_space_end = MIN2(cur_beg - 1, dead_range_end - 1);
251 const size_t size = obj_size(dead_space_beg, dead_space_end);
252 dead_closure->do_addr(bit_to_addr(dead_space_beg), size);
253 }
254 }
255
256 live_closure->set_source(bit_to_addr(range_end));
257 return complete;
258 }
259
260 #ifdef ASSERT
261 void ParMarkBitMap::verify_clear() const
262 {
263 const idx_t* const beg = (const idx_t*)_virtual_space->committed_low_addr();
264 const idx_t* const end = (const idx_t*)_virtual_space->committed_high_addr();
265 for (const idx_t* p = beg; p < end; ++p) {
266 assert(*p == 0, "bitmap not clear");
267 }
268 }
269 #endif // #ifdef ASSERT