Fri, 10 Jun 2011 15:08:36 -0700
6941923: RFE: Handling large log files produced by long running Java Applications
Summary: supply optinal flags to realize gc log rotation
Reviewed-by: ysr, jwilhelm
1 /*
2 * Copyright (c) 2003, 2011, 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 */
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"
35 HS_DTRACE_PROBE_DECL4(hs_private, hashtable__new_entry,
36 void*, unsigned int, void*, void*);
38 // This is a generic hashtable, designed to be used for the symbol
39 // and string tables.
40 //
41 // It is implemented as an open hash table with a fixed number of buckets.
42 //
43 // %note:
44 // - HashtableEntrys are allocated in blocks to reduce the space overhead.
46 BasicHashtableEntry* BasicHashtable::new_entry(unsigned int hashValue) {
47 BasicHashtableEntry* entry;
49 if (_free_list) {
50 entry = _free_list;
51 _free_list = _free_list->next();
52 } else {
53 if (_first_free_entry + _entry_size >= _end_block) {
54 int block_size = MIN2(512, MAX2((int)_table_size / 2, (int)_number_of_entries));
55 int len = _entry_size * block_size;
56 len = 1 << log2_intptr(len); // round down to power of 2
57 assert(len >= _entry_size, "");
58 _first_free_entry = NEW_C_HEAP_ARRAY(char, len);
59 _end_block = _first_free_entry + len;
60 }
61 entry = (BasicHashtableEntry*)_first_free_entry;
62 _first_free_entry += _entry_size;
63 }
65 assert(_entry_size % HeapWordSize == 0, "");
66 entry->set_hash(hashValue);
67 return entry;
68 }
71 template <class T> HashtableEntry<T>* Hashtable<T>::new_entry(unsigned int hashValue, T obj) {
72 HashtableEntry<T>* entry;
74 entry = (HashtableEntry<T>*)BasicHashtable::new_entry(hashValue);
75 entry->set_literal(obj);
76 HS_DTRACE_PROBE4(hs_private, hashtable__new_entry,
77 this, hashValue, obj, entry);
78 return entry;
79 }
82 // Reverse the order of elements in the hash buckets.
84 void BasicHashtable::reverse() {
86 for (int i = 0; i < _table_size; ++i) {
87 BasicHashtableEntry* new_list = NULL;
88 BasicHashtableEntry* p = bucket(i);
89 while (p != NULL) {
90 BasicHashtableEntry* next = p->next();
91 p->set_next(new_list);
92 new_list = p;
93 p = next;
94 }
95 *bucket_addr(i) = new_list;
96 }
97 }
100 // Copy the table to the shared space.
102 void BasicHashtable::copy_table(char** top, char* end) {
104 // Dump the hash table entries.
106 intptr_t *plen = (intptr_t*)(*top);
107 *top += sizeof(*plen);
109 int i;
110 for (i = 0; i < _table_size; ++i) {
111 for (BasicHashtableEntry** p = _buckets[i].entry_addr();
112 *p != NULL;
113 p = (*p)->next_addr()) {
114 if (*top + entry_size() > end) {
115 report_out_of_shared_space(SharedMiscData);
116 }
117 *p = (BasicHashtableEntry*)memcpy(*top, *p, entry_size());
118 *top += entry_size();
119 }
120 }
121 *plen = (char*)(*top) - (char*)plen - sizeof(*plen);
123 // Set the shared bit.
125 for (i = 0; i < _table_size; ++i) {
126 for (BasicHashtableEntry* p = bucket(i); p != NULL; p = p->next()) {
127 p->set_shared();
128 }
129 }
130 }
134 // Reverse the order of elements in the hash buckets.
136 template <class T> void Hashtable<T>::reverse(void* boundary) {
138 for (int i = 0; i < table_size(); ++i) {
139 HashtableEntry<T>* high_list = NULL;
140 HashtableEntry<T>* low_list = NULL;
141 HashtableEntry<T>* last_low_entry = NULL;
142 HashtableEntry<T>* p = bucket(i);
143 while (p != NULL) {
144 HashtableEntry<T>* next = p->next();
145 if ((void*)p->literal() >= boundary) {
146 p->set_next(high_list);
147 high_list = p;
148 } else {
149 p->set_next(low_list);
150 low_list = p;
151 if (last_low_entry == NULL) {
152 last_low_entry = p;
153 }
154 }
155 p = next;
156 }
157 if (low_list != NULL) {
158 *bucket_addr(i) = low_list;
159 last_low_entry->set_next(high_list);
160 } else {
161 *bucket_addr(i) = high_list;
162 }
163 }
164 }
167 // Dump the hash table buckets.
169 void BasicHashtable::copy_buckets(char** top, char* end) {
170 intptr_t len = _table_size * sizeof(HashtableBucket);
171 *(intptr_t*)(*top) = len;
172 *top += sizeof(intptr_t);
174 *(intptr_t*)(*top) = _number_of_entries;
175 *top += sizeof(intptr_t);
177 if (*top + len > end) {
178 report_out_of_shared_space(SharedMiscData);
179 }
180 _buckets = (HashtableBucket*)memcpy(*top, _buckets, len);
181 *top += len;
182 }
185 #ifndef PRODUCT
187 template <class T> void Hashtable<T>::print() {
188 ResourceMark rm;
190 for (int i = 0; i < table_size(); i++) {
191 HashtableEntry<T>* entry = bucket(i);
192 while(entry != NULL) {
193 tty->print("%d : ", i);
194 entry->literal()->print();
195 tty->cr();
196 entry = entry->next();
197 }
198 }
199 }
202 void BasicHashtable::verify() {
203 int count = 0;
204 for (int i = 0; i < table_size(); i++) {
205 for (BasicHashtableEntry* p = bucket(i); p != NULL; p = p->next()) {
206 ++count;
207 }
208 }
209 assert(count == number_of_entries(), "number of hashtable entries incorrect");
210 }
213 #endif // PRODUCT
216 #ifdef ASSERT
218 void BasicHashtable::verify_lookup_length(double load) {
219 if ((double)_lookup_length / (double)_lookup_count > load * 2.0) {
220 warning("Performance bug: SystemDictionary lookup_count=%d "
221 "lookup_length=%d average=%lf load=%f",
222 _lookup_count, _lookup_length,
223 (double) _lookup_length / _lookup_count, load);
224 }
225 }
227 #endif
229 // Explicitly instantiate these types
230 template class Hashtable<constantPoolOop>;
231 template class Hashtable<Symbol*>;
232 template class Hashtable<klassOop>;
233 template class Hashtable<oop>;