1 /*
2 * Copyright (c) 2001, 2010, 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 "memory/allocation.inline.hpp"
27 #include "runtime/arguments.hpp"
28 #include "runtime/java.hpp"
29 #include "runtime/mutex.hpp"
30 #include "runtime/mutexLocker.hpp"
31 #include "runtime/os.hpp"
32 #include "runtime/perfData.hpp"
33 #include "runtime/perfMemory.hpp"
34 #include "runtime/statSampler.hpp"
35 #include "utilities/globalDefinitions.hpp"
36
37 // Prefix of performance data file.
38 const char PERFDATA_NAME[] = "hsperfdata";
39
40 // Add 1 for the '_' character between PERFDATA_NAME and pid. The '\0' terminating
41 // character will be included in the sizeof(PERFDATA_NAME) operation.
42 static const size_t PERFDATA_FILENAME_LEN = sizeof(PERFDATA_NAME) +
43 UINT_CHARS + 1;
44
45 char* PerfMemory::_start = NULL;
46 char* PerfMemory::_end = NULL;
47 char* PerfMemory::_top = NULL;
48 size_t PerfMemory::_capacity = 0;
49 jint PerfMemory::_initialized = false;
50 PerfDataPrologue* PerfMemory::_prologue = NULL;
51
52 void perfMemory_init() {
53
54 if (!UsePerfData) return;
55
56 PerfMemory::initialize();
57 }
58
59 void perfMemory_exit() {
60
61 if (!UsePerfData) return;
62 if (!PerfMemory::is_initialized()) return;
63
64 // if the StatSampler is active, then we don't want to remove
65 // resources it may be dependent on. Typically, the StatSampler
66 // is disengaged from the watcher thread when this method is called,
67 // but it is not disengaged if this method is invoked during a
68 // VM abort.
69 //
70 if (!StatSampler::is_active())
71 PerfDataManager::destroy();
72
73 // remove the persistent external resources, if any. this method
74 // does not unmap or invalidate any virtual memory allocated during
75 // initialization.
76 //
77 PerfMemory::destroy();
78 }
79
80 void PerfMemory::initialize() {
81
82 if (_prologue != NULL)
83 // initialization already performed
84 return;
85
86 size_t capacity = align_size_up(PerfDataMemorySize,
87 os::vm_allocation_granularity());
88
89 if (PerfTraceMemOps) {
90 tty->print("PerfDataMemorySize = " SIZE_FORMAT ","
91 " os::vm_allocation_granularity = " SIZE_FORMAT ","
92 " adjusted size = " SIZE_FORMAT "\n",
93 PerfDataMemorySize,
94 os::vm_allocation_granularity(),
95 capacity);
96 }
97
98 // allocate PerfData memory region
99 create_memory_region(capacity);
100
101 if (_start == NULL) {
102
103 // the PerfMemory region could not be created as desired. Rather
104 // than terminating the JVM, we revert to creating the instrumentation
105 // on the C heap. When running in this mode, external monitoring
106 // clients cannot attach to and monitor this JVM.
107 //
108 // the warning is issued only in debug mode in order to avoid
109 // additional output to the stdout or stderr output streams.
110 //
111 if (PrintMiscellaneous && Verbose) {
112 warning("Could not create PerfData Memory region, reverting to malloc");
113 }
114
115 _prologue = NEW_C_HEAP_OBJ(PerfDataPrologue);
116 }
117 else {
118
119 // the PerfMemory region was created as expected.
120
121 if (PerfTraceMemOps) {
122 tty->print("PerfMemory created: address = " INTPTR_FORMAT ","
123 " size = " SIZE_FORMAT "\n",
124 (void*)_start,
125 _capacity);
126 }
127
128 _prologue = (PerfDataPrologue *)_start;
129 _end = _start + _capacity;
130 _top = _start + sizeof(PerfDataPrologue);
131 }
132
133 assert(_prologue != NULL, "prologue pointer must be initialized");
134
135 #ifdef VM_LITTLE_ENDIAN
136 _prologue->magic = (jint)0xc0c0feca;
137 _prologue->byte_order = PERFDATA_LITTLE_ENDIAN;
138 #else
139 _prologue->magic = (jint)0xcafec0c0;
140 _prologue->byte_order = PERFDATA_BIG_ENDIAN;
141 #endif
142
143 _prologue->major_version = PERFDATA_MAJOR_VERSION;
144 _prologue->minor_version = PERFDATA_MINOR_VERSION;
145 _prologue->accessible = 0;
146
147 _prologue->entry_offset = sizeof(PerfDataPrologue);
148 _prologue->num_entries = 0;
149 _prologue->used = 0;
150 _prologue->overflow = 0;
151 _prologue->mod_time_stamp = 0;
152
153 OrderAccess::release_store(&_initialized, 1);
154 }
155
156 void PerfMemory::destroy() {
157
158 assert(_prologue != NULL, "prologue pointer must be initialized");
159
160 if (_start != NULL && _prologue->overflow != 0) {
161
162 // This state indicates that the contiguous memory region exists and
163 // that it wasn't large enough to hold all the counters. In this case,
164 // we output a warning message to the user on exit if the -XX:+Verbose
165 // flag is set (a debug only flag). External monitoring tools can detect
166 // this condition by monitoring the _prologue->overflow word.
167 //
168 // There are two tunables that can help resolve this issue:
169 // - increase the size of the PerfMemory with -XX:PerfDataMemorySize=<n>
170 // - decrease the maximum string constant length with
171 // -XX:PerfMaxStringConstLength=<n>
172 //
173 if (PrintMiscellaneous && Verbose) {
174 warning("PerfMemory Overflow Occurred.\n"
175 "\tCapacity = " SIZE_FORMAT " bytes"
176 " Used = " SIZE_FORMAT " bytes"
177 " Overflow = " INT32_FORMAT " bytes"
178 "\n\tUse -XX:PerfDataMemorySize=<size> to specify larger size.",
179 PerfMemory::capacity(),
180 PerfMemory::used(),
181 _prologue->overflow);
182 }
183 }
184
185 if (_start != NULL) {
186
187 // this state indicates that the contiguous memory region was successfully
188 // and that persistent resources may need to be cleaned up. This is
189 // expected to be the typical condition.
190 //
191 delete_memory_region();
192 }
193
194 _start = NULL;
195 _end = NULL;
196 _top = NULL;
197 _prologue = NULL;
198 _capacity = 0;
199 }
200
201 // allocate an aligned block of memory from the PerfData memory
202 // region. This method assumes that the PerfData memory region
203 // was aligned on a double word boundary when created.
204 //
205 char* PerfMemory::alloc(size_t size) {
206
207 if (!UsePerfData) return NULL;
208
209 MutexLocker ml(PerfDataMemAlloc_lock);
210
211 assert(_prologue != NULL, "called before initialization");
212
213 // check that there is enough memory for this request
214 if ((_top + size) >= _end) {
215
216 _prologue->overflow += (jint)size;
217
218 return NULL;
219 }
220
221 char* result = _top;
222
223 _top += size;
224
225 assert(contains(result), "PerfData memory pointer out of range");
226
227 _prologue->used = (jint)used();
228 _prologue->num_entries = _prologue->num_entries + 1;
229
230 return result;
231 }
232
233 void PerfMemory::mark_updated() {
234 if (!UsePerfData) return;
235
236 _prologue->mod_time_stamp = os::elapsed_counter();
237 }
238
239 // Returns the complete path including the file name of performance data file.
240 // Caller is expected to release the allocated memory.
241 char* PerfMemory::get_perfdata_file_path() {
242 char* dest_file = NULL;
243
244 if (PerfDataSaveFile != NULL) {
245 // dest_file_name stores the validated file name if file_name
246 // contains %p which will be replaced by pid.
247 dest_file = NEW_C_HEAP_ARRAY(char, JVM_MAXPATHLEN);
248 if(!Arguments::copy_expand_pid(PerfDataSaveFile, strlen(PerfDataSaveFile),
249 dest_file, JVM_MAXPATHLEN)) {
250 FREE_C_HEAP_ARRAY(char, dest_file);
251 if (PrintMiscellaneous && Verbose) {
252 warning("Invalid performance data file path name specified, "\
253 "fall back to a default name");
254 }
255 } else {
256 return dest_file;
257 }
258 }
259 // create the name of the file for retaining the instrumentation memory.
260 dest_file = NEW_C_HEAP_ARRAY(char, PERFDATA_FILENAME_LEN);
261 jio_snprintf(dest_file, PERFDATA_FILENAME_LEN,
262 "%s_%d", PERFDATA_NAME, os::current_process_id());
263
264 return dest_file;
265 }