1 /*
2 * Copyright (c) 2001, 2015, 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/orderAccess.inline.hpp"
32 #include "runtime/os.hpp"
33 #include "runtime/perfData.hpp"
34 #include "runtime/perfMemory.hpp"
35 #include "runtime/safepoint.hpp"
36 #include "runtime/statSampler.hpp"
37 #include "utilities/globalDefinitions.hpp"
38
39 // Prefix of performance data file.
40 const char PERFDATA_NAME[] = "hsperfdata";
41
42 // Add 1 for the '_' character between PERFDATA_NAME and pid. The '\0' terminating
43 // character will be included in the sizeof(PERFDATA_NAME) operation.
44 static const size_t PERFDATA_FILENAME_LEN = sizeof(PERFDATA_NAME) +
45 UINT_CHARS + 1;
46
47 char* PerfMemory::_start = NULL;
48 char* PerfMemory::_end = NULL;
49 char* PerfMemory::_top = NULL;
50 size_t PerfMemory::_capacity = 0;
51 jint PerfMemory::_initialized = false;
52 PerfDataPrologue* PerfMemory::_prologue = NULL;
53
54 void perfMemory_init() {
55
56 if (!UsePerfData) return;
57
58 PerfMemory::initialize();
59 }
60
61 void perfMemory_exit() {
62
63 if (!UsePerfData) return;
64 if (!PerfMemory::is_initialized()) return;
65
66 // Only destroy PerfData objects if we're at a safepoint and the
67 // StatSampler is not active. Otherwise, we risk removing PerfData
68 // objects that are currently being used by running JavaThreads
69 // or the StatSampler. This method is invoked while we are not at
70 // a safepoint during a VM abort so leaving the PerfData objects
71 // around may also help diagnose the failure. In rare cases,
72 // PerfData objects are used in parallel with a safepoint. See
73 // the work around in PerfDataManager::destroy().
74 //
75 if (SafepointSynchronize::is_at_safepoint() && !StatSampler::is_active()) {
76 PerfDataManager::destroy();
77 }
78
79 // Remove the persistent external resources, if any. This method
80 // does not unmap or invalidate any virtual memory allocated during
81 // initialization.
82 //
83 PerfMemory::destroy();
84 }
85
86 void PerfMemory::initialize() {
87
88 if (_prologue != NULL)
89 // initialization already performed
90 return;
91
92 size_t capacity = align_size_up(PerfDataMemorySize,
93 os::vm_allocation_granularity());
94
95 if (PerfTraceMemOps) {
96 tty->print("PerfDataMemorySize = " INTX_FORMAT ","
97 " os::vm_allocation_granularity = %d,"
98 " adjusted size = " SIZE_FORMAT "\n",
99 PerfDataMemorySize,
100 os::vm_allocation_granularity(),
101 capacity);
102 }
103
104 // allocate PerfData memory region
105 create_memory_region(capacity);
106
107 if (_start == NULL) {
108
109 // the PerfMemory region could not be created as desired. Rather
110 // than terminating the JVM, we revert to creating the instrumentation
111 // on the C heap. When running in this mode, external monitoring
112 // clients cannot attach to and monitor this JVM.
113 //
114 // the warning is issued only in debug mode in order to avoid
115 // additional output to the stdout or stderr output streams.
116 //
117 if (PrintMiscellaneous && Verbose) {
118 warning("Could not create PerfData Memory region, reverting to malloc");
119 }
120
121 _prologue = NEW_C_HEAP_OBJ(PerfDataPrologue, mtInternal);
122 }
123 else {
124
125 // the PerfMemory region was created as expected.
126
127 if (PerfTraceMemOps) {
128 tty->print("PerfMemory created: address = " INTPTR_FORMAT ","
129 " size = " SIZE_FORMAT "\n",
130 p2i(_start),
131 _capacity);
132 }
133
134 _prologue = (PerfDataPrologue *)_start;
135 _end = _start + _capacity;
136 _top = _start + sizeof(PerfDataPrologue);
137 }
138
139 assert(_prologue != NULL, "prologue pointer must be initialized");
140
141 #ifdef VM_LITTLE_ENDIAN
142 _prologue->magic = (jint)0xc0c0feca;
143 _prologue->byte_order = PERFDATA_LITTLE_ENDIAN;
144 #else
145 _prologue->magic = (jint)0xcafec0c0;
146 _prologue->byte_order = PERFDATA_BIG_ENDIAN;
147 #endif
148
149 _prologue->major_version = PERFDATA_MAJOR_VERSION;
150 _prologue->minor_version = PERFDATA_MINOR_VERSION;
151 _prologue->accessible = 0;
152
153 _prologue->entry_offset = sizeof(PerfDataPrologue);
154 _prologue->num_entries = 0;
155 _prologue->used = 0;
156 _prologue->overflow = 0;
157 _prologue->mod_time_stamp = 0;
158
159 OrderAccess::release_store(&_initialized, 1);
160 }
161
162 void PerfMemory::destroy() {
163
164 if (_prologue == NULL) return;
165
166 if (_start != NULL && _prologue->overflow != 0) {
167
168 // This state indicates that the contiguous memory region exists and
169 // that it wasn't large enough to hold all the counters. In this case,
170 // we output a warning message to the user on exit if the -XX:+Verbose
171 // flag is set (a debug only flag). External monitoring tools can detect
172 // this condition by monitoring the _prologue->overflow word.
173 //
174 // There are two tunables that can help resolve this issue:
175 // - increase the size of the PerfMemory with -XX:PerfDataMemorySize=<n>
176 // - decrease the maximum string constant length with
177 // -XX:PerfMaxStringConstLength=<n>
178 //
179 if (PrintMiscellaneous && Verbose) {
180 warning("PerfMemory Overflow Occurred.\n"
181 "\tCapacity = " SIZE_FORMAT " bytes"
182 " Used = " SIZE_FORMAT " bytes"
183 " Overflow = " INT32_FORMAT " bytes"
184 "\n\tUse -XX:PerfDataMemorySize=<size> to specify larger size.",
185 PerfMemory::capacity(),
186 PerfMemory::used(),
187 _prologue->overflow);
188 }
189 }
190
191 if (_start != NULL) {
192
193 // this state indicates that the contiguous memory region was successfully
194 // and that persistent resources may need to be cleaned up. This is
195 // expected to be the typical condition.
196 //
197 delete_memory_region();
198 }
199
200 _start = NULL;
201 _end = NULL;
202 _top = NULL;
203 _prologue = NULL;
204 _capacity = 0;
205 }
206
207 // allocate an aligned block of memory from the PerfData memory
208 // region. This method assumes that the PerfData memory region
209 // was aligned on a double word boundary when created.
210 //
211 char* PerfMemory::alloc(size_t size) {
212
213 if (!UsePerfData) return NULL;
214
215 MutexLocker ml(PerfDataMemAlloc_lock);
216
217 assert(_prologue != NULL, "called before initialization");
218
219 // check that there is enough memory for this request
220 if ((_top + size) >= _end) {
221
222 _prologue->overflow += (jint)size;
223
224 return NULL;
225 }
226
227 char* result = _top;
228
229 _top += size;
230
231 assert(contains(result), "PerfData memory pointer out of range");
232
233 _prologue->used = (jint)used();
234 _prologue->num_entries = _prologue->num_entries + 1;
235
236 return result;
237 }
238
239 void PerfMemory::mark_updated() {
240 if (!UsePerfData) return;
241
242 _prologue->mod_time_stamp = os::elapsed_counter();
243 }
244
245 // Returns the complete path including the file name of performance data file.
246 // Caller is expected to release the allocated memory.
247 char* PerfMemory::get_perfdata_file_path() {
248 char* dest_file = NULL;
249
250 if (PerfDataSaveFile != NULL) {
251 // dest_file_name stores the validated file name if file_name
252 // contains %p which will be replaced by pid.
253 dest_file = NEW_C_HEAP_ARRAY(char, JVM_MAXPATHLEN, mtInternal);
254 if(!Arguments::copy_expand_pid(PerfDataSaveFile, strlen(PerfDataSaveFile),
255 dest_file, JVM_MAXPATHLEN)) {
256 FREE_C_HEAP_ARRAY(char, dest_file);
257 if (PrintMiscellaneous && Verbose) {
258 warning("Invalid performance data file path name specified, "\
259 "fall back to a default name");
260 }
261 } else {
262 return dest_file;
263 }
264 }
265 // create the name of the file for retaining the instrumentation memory.
266 dest_file = NEW_C_HEAP_ARRAY(char, PERFDATA_FILENAME_LEN, mtInternal);
267 jio_snprintf(dest_file, PERFDATA_FILENAME_LEN,
268 "%s_%d", PERFDATA_NAME, os::current_process_id());
269
270 return dest_file;
271 }