1 /*
2 * Copyright (c) 2001, 2008, 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 "incls/_precompiled.incl"
26 # include "incls/_perfMemory.cpp.incl"
27
28 // Prefix of performance data file.
29 const char PERFDATA_NAME[] = "hsperfdata";
30
31 // Add 1 for the '_' character between PERFDATA_NAME and pid. The '\0' terminating
32 // character will be included in the sizeof(PERFDATA_NAME) operation.
33 static const size_t PERFDATA_FILENAME_LEN = sizeof(PERFDATA_NAME) +
34 UINT_CHARS + 1;
35
36 char* PerfMemory::_start = NULL;
37 char* PerfMemory::_end = NULL;
38 char* PerfMemory::_top = NULL;
39 size_t PerfMemory::_capacity = 0;
40 jint PerfMemory::_initialized = false;
41 PerfDataPrologue* PerfMemory::_prologue = NULL;
42
43 void perfMemory_init() {
44
45 if (!UsePerfData) return;
46
47 PerfMemory::initialize();
48 }
49
50 void perfMemory_exit() {
51
52 if (!UsePerfData) return;
53 if (!PerfMemory::is_initialized()) return;
54
55 // if the StatSampler is active, then we don't want to remove
56 // resources it may be dependent on. Typically, the StatSampler
57 // is disengaged from the watcher thread when this method is called,
58 // but it is not disengaged if this method is invoked during a
59 // VM abort.
60 //
61 if (!StatSampler::is_active())
62 PerfDataManager::destroy();
63
64 // remove the persistent external resources, if any. this method
65 // does not unmap or invalidate any virtual memory allocated during
66 // initialization.
67 //
68 PerfMemory::destroy();
69 }
70
71 void PerfMemory::initialize() {
72
73 if (_prologue != NULL)
74 // initialization already performed
75 return;
76
77 size_t capacity = align_size_up(PerfDataMemorySize,
78 os::vm_allocation_granularity());
79
80 if (PerfTraceMemOps) {
81 tty->print("PerfDataMemorySize = " SIZE_FORMAT ","
82 " os::vm_allocation_granularity = " SIZE_FORMAT ","
83 " adjusted size = " SIZE_FORMAT "\n",
84 PerfDataMemorySize,
85 os::vm_allocation_granularity(),
86 capacity);
87 }
88
89 // allocate PerfData memory region
90 create_memory_region(capacity);
91
92 if (_start == NULL) {
93
94 // the PerfMemory region could not be created as desired. Rather
95 // than terminating the JVM, we revert to creating the instrumentation
96 // on the C heap. When running in this mode, external monitoring
97 // clients cannot attach to and monitor this JVM.
98 //
99 // the warning is issued only in debug mode in order to avoid
100 // additional output to the stdout or stderr output streams.
101 //
102 if (PrintMiscellaneous && Verbose) {
103 warning("Could not create PerfData Memory region, reverting to malloc");
104 }
105
106 _prologue = NEW_C_HEAP_OBJ(PerfDataPrologue);
107 }
108 else {
109
110 // the PerfMemory region was created as expected.
111
112 if (PerfTraceMemOps) {
113 tty->print("PerfMemory created: address = " INTPTR_FORMAT ","
114 " size = " SIZE_FORMAT "\n",
115 (void*)_start,
116 _capacity);
117 }
118
119 _prologue = (PerfDataPrologue *)_start;
120 _end = _start + _capacity;
121 _top = _start + sizeof(PerfDataPrologue);
122 }
123
124 assert(_prologue != NULL, "prologue pointer must be initialized");
125
126 #ifdef VM_LITTLE_ENDIAN
127 _prologue->magic = (jint)0xc0c0feca;
128 _prologue->byte_order = PERFDATA_LITTLE_ENDIAN;
129 #else
130 _prologue->magic = (jint)0xcafec0c0;
131 _prologue->byte_order = PERFDATA_BIG_ENDIAN;
132 #endif
133
134 _prologue->major_version = PERFDATA_MAJOR_VERSION;
135 _prologue->minor_version = PERFDATA_MINOR_VERSION;
136 _prologue->accessible = 0;
137
138 _prologue->entry_offset = sizeof(PerfDataPrologue);
139 _prologue->num_entries = 0;
140 _prologue->used = 0;
141 _prologue->overflow = 0;
142 _prologue->mod_time_stamp = 0;
143
144 OrderAccess::release_store(&_initialized, 1);
145 }
146
147 void PerfMemory::destroy() {
148
149 assert(_prologue != NULL, "prologue pointer must be initialized");
150
151 if (_start != NULL && _prologue->overflow != 0) {
152
153 // This state indicates that the contiguous memory region exists and
154 // that it wasn't large enough to hold all the counters. In this case,
155 // we output a warning message to the user on exit if the -XX:+Verbose
156 // flag is set (a debug only flag). External monitoring tools can detect
157 // this condition by monitoring the _prologue->overflow word.
158 //
159 // There are two tunables that can help resolve this issue:
160 // - increase the size of the PerfMemory with -XX:PerfDataMemorySize=<n>
161 // - decrease the maximum string constant length with
162 // -XX:PerfMaxStringConstLength=<n>
163 //
164 if (PrintMiscellaneous && Verbose) {
165 warning("PerfMemory Overflow Occurred.\n"
166 "\tCapacity = " SIZE_FORMAT " bytes"
167 " Used = " SIZE_FORMAT " bytes"
168 " Overflow = " INT32_FORMAT " bytes"
169 "\n\tUse -XX:PerfDataMemorySize=<size> to specify larger size.",
170 PerfMemory::capacity(),
171 PerfMemory::used(),
172 _prologue->overflow);
173 }
174 }
175
176 if (_start != NULL) {
177
178 // this state indicates that the contiguous memory region was successfully
179 // and that persistent resources may need to be cleaned up. This is
180 // expected to be the typical condition.
181 //
182 delete_memory_region();
183 }
184
185 _start = NULL;
186 _end = NULL;
187 _top = NULL;
188 _prologue = NULL;
189 _capacity = 0;
190 }
191
192 // allocate an aligned block of memory from the PerfData memory
193 // region. This method assumes that the PerfData memory region
194 // was aligned on a double word boundary when created.
195 //
196 char* PerfMemory::alloc(size_t size) {
197
198 if (!UsePerfData) return NULL;
199
200 MutexLocker ml(PerfDataMemAlloc_lock);
201
202 assert(_prologue != NULL, "called before initialization");
203
204 // check that there is enough memory for this request
205 if ((_top + size) >= _end) {
206
207 _prologue->overflow += (jint)size;
208
209 return NULL;
210 }
211
212 char* result = _top;
213
214 _top += size;
215
216 assert(contains(result), "PerfData memory pointer out of range");
217
218 _prologue->used = (jint)used();
219 _prologue->num_entries = _prologue->num_entries + 1;
220
221 return result;
222 }
223
224 void PerfMemory::mark_updated() {
225 if (!UsePerfData) return;
226
227 _prologue->mod_time_stamp = os::elapsed_counter();
228 }
229
230 // Returns the complete path including the file name of performance data file.
231 // Caller is expected to release the allocated memory.
232 char* PerfMemory::get_perfdata_file_path() {
233 char* dest_file = NULL;
234
235 if (PerfDataSaveFile != NULL) {
236 // dest_file_name stores the validated file name if file_name
237 // contains %p which will be replaced by pid.
238 dest_file = NEW_C_HEAP_ARRAY(char, JVM_MAXPATHLEN);
239 if(!Arguments::copy_expand_pid(PerfDataSaveFile, strlen(PerfDataSaveFile),
240 dest_file, JVM_MAXPATHLEN)) {
241 FREE_C_HEAP_ARRAY(char, dest_file);
242 if (PrintMiscellaneous && Verbose) {
243 warning("Invalid performance data file path name specified, "\
244 "fall back to a default name");
245 }
246 } else {
247 return dest_file;
248 }
249 }
250 // create the name of the file for retaining the instrumentation memory.
251 dest_file = NEW_C_HEAP_ARRAY(char, PERFDATA_FILENAME_LEN);
252 jio_snprintf(dest_file, PERFDATA_FILENAME_LEN,
253 "%s_%d", PERFDATA_NAME, os::current_process_id());
254
255 return dest_file;
256 }