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annotate src/share/vm/utilities/hashtable.cpp @ 2137:ffd725ff6943
Merge
author | johnc |
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date | Thu, 13 Jan 2011 17:19:21 -0800 |
parents | f95d63e2154a |
children | 3582bf76420e |
rev | line source |
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0 | 1 /* |
1972 | 2 * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved. |
0 | 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 * | |
1552
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
1972 | 25 #include "precompiled.hpp" |
26 #include "memory/allocation.inline.hpp" | |
27 #include "memory/resourceArea.hpp" | |
28 #include "oops/oop.inline.hpp" | |
29 #include "runtime/safepoint.hpp" | |
30 #include "utilities/dtrace.hpp" | |
31 #include "utilities/hashtable.hpp" | |
32 #include "utilities/hashtable.inline.hpp" | |
0 | 33 |
34 HS_DTRACE_PROBE_DECL4(hs_private, hashtable__new_entry, | |
35 void*, unsigned int, oop, void*); | |
36 | |
37 // This is a generic hashtable, designed to be used for the symbol | |
38 // and string tables. | |
39 // | |
40 // It is implemented as an open hash table with a fixed number of buckets. | |
41 // | |
42 // %note: | |
43 // - HashtableEntrys are allocated in blocks to reduce the space overhead. | |
44 | |
45 BasicHashtableEntry* BasicHashtable::new_entry(unsigned int hashValue) { | |
46 BasicHashtableEntry* entry; | |
47 | |
48 if (_free_list) { | |
49 entry = _free_list; | |
50 _free_list = _free_list->next(); | |
51 } else { | |
432 | 52 if (_first_free_entry + _entry_size >= _end_block) { |
53 int block_size = MIN2(512, MAX2((int)_table_size / 2, (int)_number_of_entries)); | |
0 | 54 int len = _entry_size * block_size; |
432 | 55 len = 1 << log2_intptr(len); // round down to power of 2 |
56 assert(len >= _entry_size, ""); | |
0 | 57 _first_free_entry = NEW_C_HEAP_ARRAY(char, len); |
58 _end_block = _first_free_entry + len; | |
59 } | |
60 entry = (BasicHashtableEntry*)_first_free_entry; | |
61 _first_free_entry += _entry_size; | |
62 } | |
63 | |
432 | 64 assert(_entry_size % HeapWordSize == 0, ""); |
0 | 65 entry->set_hash(hashValue); |
66 return entry; | |
67 } | |
68 | |
69 | |
70 HashtableEntry* Hashtable::new_entry(unsigned int hashValue, oop obj) { | |
71 HashtableEntry* entry; | |
72 | |
73 entry = (HashtableEntry*)BasicHashtable::new_entry(hashValue); | |
74 entry->set_literal(obj); // clears literal string field | |
75 HS_DTRACE_PROBE4(hs_private, hashtable__new_entry, | |
76 this, hashValue, obj, entry); | |
77 return entry; | |
78 } | |
79 | |
80 | |
81 // GC support | |
82 | |
83 void Hashtable::unlink(BoolObjectClosure* is_alive) { | |
84 // Readers of the table are unlocked, so we should only be removing | |
85 // entries at a safepoint. | |
86 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); | |
87 for (int i = 0; i < table_size(); ++i) { | |
88 for (HashtableEntry** p = bucket_addr(i); *p != NULL; ) { | |
89 HashtableEntry* entry = *p; | |
90 if (entry->is_shared()) { | |
91 break; | |
92 } | |
93 assert(entry->literal() != NULL, "just checking"); | |
94 if (is_alive->do_object_b(entry->literal())) { | |
95 p = entry->next_addr(); | |
96 } else { | |
97 *p = entry->next(); | |
98 free_entry(entry); | |
99 } | |
100 } | |
101 } | |
102 } | |
103 | |
104 | |
105 void Hashtable::oops_do(OopClosure* f) { | |
106 for (int i = 0; i < table_size(); ++i) { | |
107 HashtableEntry** p = bucket_addr(i); | |
108 HashtableEntry* entry = bucket(i); | |
109 while (entry != NULL) { | |
110 f->do_oop(entry->literal_addr()); | |
111 | |
112 // Did the closure remove the literal from the table? | |
113 if (entry->literal() == NULL) { | |
114 assert(!entry->is_shared(), "immutable hashtable entry?"); | |
115 *p = entry->next(); | |
116 free_entry(entry); | |
117 } else { | |
118 p = entry->next_addr(); | |
119 } | |
120 entry = (HashtableEntry*)HashtableEntry::make_ptr(*p); | |
121 } | |
122 } | |
123 } | |
124 | |
125 | |
126 // Reverse the order of elements in the hash buckets. | |
127 | |
128 void BasicHashtable::reverse() { | |
129 | |
130 for (int i = 0; i < _table_size; ++i) { | |
131 BasicHashtableEntry* new_list = NULL; | |
132 BasicHashtableEntry* p = bucket(i); | |
133 while (p != NULL) { | |
134 BasicHashtableEntry* next = p->next(); | |
135 p->set_next(new_list); | |
136 new_list = p; | |
137 p = next; | |
138 } | |
139 *bucket_addr(i) = new_list; | |
140 } | |
141 } | |
142 | |
143 | |
144 // Copy the table to the shared space. | |
145 | |
146 void BasicHashtable::copy_table(char** top, char* end) { | |
147 | |
148 // Dump the hash table entries. | |
149 | |
150 intptr_t *plen = (intptr_t*)(*top); | |
151 *top += sizeof(*plen); | |
152 | |
153 int i; | |
154 for (i = 0; i < _table_size; ++i) { | |
155 for (BasicHashtableEntry** p = _buckets[i].entry_addr(); | |
156 *p != NULL; | |
157 p = (*p)->next_addr()) { | |
158 if (*top + entry_size() > end) { | |
159 warning("\nThe shared miscellaneous data space is not large " | |
160 "enough to \npreload requested classes. Use " | |
161 "-XX:SharedMiscDataSize= to increase \nthe initial " | |
162 "size of the miscellaneous data space.\n"); | |
163 exit(2); | |
164 } | |
165 *p = (BasicHashtableEntry*)memcpy(*top, *p, entry_size()); | |
166 *top += entry_size(); | |
167 } | |
168 } | |
169 *plen = (char*)(*top) - (char*)plen - sizeof(*plen); | |
170 | |
171 // Set the shared bit. | |
172 | |
173 for (i = 0; i < _table_size; ++i) { | |
174 for (BasicHashtableEntry* p = bucket(i); p != NULL; p = p->next()) { | |
175 p->set_shared(); | |
176 } | |
177 } | |
178 } | |
179 | |
180 | |
181 | |
182 // Reverse the order of elements in the hash buckets. | |
183 | |
184 void Hashtable::reverse(void* boundary) { | |
185 | |
186 for (int i = 0; i < table_size(); ++i) { | |
187 HashtableEntry* high_list = NULL; | |
188 HashtableEntry* low_list = NULL; | |
189 HashtableEntry* last_low_entry = NULL; | |
190 HashtableEntry* p = bucket(i); | |
191 while (p != NULL) { | |
192 HashtableEntry* next = p->next(); | |
193 if ((void*)p->literal() >= boundary) { | |
194 p->set_next(high_list); | |
195 high_list = p; | |
196 } else { | |
197 p->set_next(low_list); | |
198 low_list = p; | |
199 if (last_low_entry == NULL) { | |
200 last_low_entry = p; | |
201 } | |
202 } | |
203 p = next; | |
204 } | |
205 if (low_list != NULL) { | |
206 *bucket_addr(i) = low_list; | |
207 last_low_entry->set_next(high_list); | |
208 } else { | |
209 *bucket_addr(i) = high_list; | |
210 } | |
211 } | |
212 } | |
213 | |
214 | |
215 // Dump the hash table buckets. | |
216 | |
217 void BasicHashtable::copy_buckets(char** top, char* end) { | |
218 intptr_t len = _table_size * sizeof(HashtableBucket); | |
219 *(intptr_t*)(*top) = len; | |
220 *top += sizeof(intptr_t); | |
221 | |
222 *(intptr_t*)(*top) = _number_of_entries; | |
223 *top += sizeof(intptr_t); | |
224 | |
225 if (*top + len > end) { | |
226 warning("\nThe shared miscellaneous data space is not large " | |
227 "enough to \npreload requested classes. Use " | |
228 "-XX:SharedMiscDataSize= to increase \nthe initial " | |
229 "size of the miscellaneous data space.\n"); | |
230 exit(2); | |
231 } | |
232 _buckets = (HashtableBucket*)memcpy(*top, _buckets, len); | |
233 *top += len; | |
234 } | |
235 | |
236 | |
237 #ifndef PRODUCT | |
238 | |
239 void Hashtable::print() { | |
240 ResourceMark rm; | |
241 | |
242 for (int i = 0; i < table_size(); i++) { | |
243 HashtableEntry* entry = bucket(i); | |
244 while(entry != NULL) { | |
245 tty->print("%d : ", i); | |
246 entry->literal()->print(); | |
247 tty->cr(); | |
248 entry = entry->next(); | |
249 } | |
250 } | |
251 } | |
252 | |
253 | |
254 void BasicHashtable::verify() { | |
255 int count = 0; | |
256 for (int i = 0; i < table_size(); i++) { | |
257 for (BasicHashtableEntry* p = bucket(i); p != NULL; p = p->next()) { | |
258 ++count; | |
259 } | |
260 } | |
261 assert(count == number_of_entries(), "number of hashtable entries incorrect"); | |
262 } | |
263 | |
264 | |
265 #endif // PRODUCT | |
266 | |
267 | |
268 #ifdef ASSERT | |
269 | |
270 void BasicHashtable::verify_lookup_length(double load) { | |
271 if ((double)_lookup_length / (double)_lookup_count > load * 2.0) { | |
272 warning("Performance bug: SystemDictionary lookup_count=%d " | |
273 "lookup_length=%d average=%lf load=%f", | |
274 _lookup_count, _lookup_length, | |
275 (double) _lookup_length / _lookup_count, load); | |
276 } | |
277 } | |
278 | |
279 #endif |