1 /*
2 * Copyright (c) 2001, 2017, 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 "logging/log.hpp"
27 #include "memory/allocation.inline.hpp"
28 #include "runtime/arguments.hpp"
29 #include "runtime/java.hpp"
30 #include "runtime/mutex.hpp"
31 #include "runtime/mutexLocker.hpp"
32 #include "runtime/orderAccess.inline.hpp"
33 #include "runtime/os.hpp"
34 #include "runtime/perfData.hpp"
35 #include "runtime/perfMemory.hpp"
36 #include "runtime/safepoint.hpp"
37 #include "runtime/statSampler.hpp"
38 #include "utilities/globalDefinitions.hpp"
39
40 // Prefix of performance data file.
41 const char PERFDATA_NAME[] = "hsperfdata";
42
43 // Add 1 for the '_' character between PERFDATA_NAME and pid. The '\0' terminating
44 // character will be included in the sizeof(PERFDATA_NAME) operation.
45 static const size_t PERFDATA_FILENAME_LEN = sizeof(PERFDATA_NAME) +
46 UINT_CHARS + 1;
47
48 char* PerfMemory::_start = NULL;
49 char* PerfMemory::_end = NULL;
50 char* PerfMemory::_top = NULL;
51 size_t PerfMemory::_capacity = 0;
52 jint PerfMemory::_initialized = false;
53 PerfDataPrologue* PerfMemory::_prologue = NULL;
54
55 void perfMemory_init() {
56
57 if (!UsePerfData) return;
58
59 PerfMemory::initialize();
60 }
61
62 void perfMemory_exit() {
63
64 if (!UsePerfData) return;
65 if (!PerfMemory::is_initialized()) return;
66
67 // Only destroy PerfData objects if we're at a safepoint and the
68 // StatSampler is not active. Otherwise, we risk removing PerfData
69 // objects that are currently being used by running JavaThreads
70 // or the StatSampler. This method is invoked while we are not at
71 // a safepoint during a VM abort so leaving the PerfData objects
72 // around may also help diagnose the failure. In rare cases,
73 // PerfData objects are used in parallel with a safepoint. See
74 // the work around in PerfDataManager::destroy().
75 //
76 if (SafepointSynchronize::is_at_safepoint() && !StatSampler::is_active()) {
77 PerfDataManager::destroy();
78 }
79
80 // Remove the persistent external resources, if any. This method
81 // does not unmap or invalidate any virtual memory allocated during
82 // initialization.
83 //
84 PerfMemory::destroy();
85 }
86
87 void PerfMemory::initialize() {
88
89 if (_prologue != NULL)
90 // initialization already performed
91 return;
92
93 size_t capacity = align_size_up(PerfDataMemorySize,
94 os::vm_allocation_granularity());
95
96 log_debug(perf, memops)("PerfDataMemorySize = " SIZE_FORMAT ","
97 " os::vm_allocation_granularity = %d,"
98 " adjusted size = " SIZE_FORMAT "\n",
99 PerfDataMemorySize,
100 os::vm_allocation_granularity(),
101 capacity);
102
103 // allocate PerfData memory region
104 create_memory_region(capacity);
105
106 if (_start == NULL) {
107
108 // the PerfMemory region could not be created as desired. Rather
109 // than terminating the JVM, we revert to creating the instrumentation
110 // on the C heap. When running in this mode, external monitoring
111 // clients cannot attach to and monitor this JVM.
112 //
113 // the warning is issued only in debug mode in order to avoid
114 // additional output to the stdout or stderr output streams.
115 //
116 if (PrintMiscellaneous && Verbose) {
117 warning("Could not create PerfData Memory region, reverting to malloc");
118 }
119
120 _prologue = NEW_C_HEAP_OBJ(PerfDataPrologue, mtInternal);
121 }
122 else {
123
124 // the PerfMemory region was created as expected.
125
126 log_debug(perf, memops)("PerfMemory created: address = " INTPTR_FORMAT ","
127 " size = " SIZE_FORMAT "\n",
128 p2i(_start),
129 _capacity);
130
131 _prologue = (PerfDataPrologue *)_start;
132 _end = _start + _capacity;
133 _top = _start + sizeof(PerfDataPrologue);
134 }
135
136 assert(_prologue != NULL, "prologue pointer must be initialized");
137
138 #ifdef VM_LITTLE_ENDIAN
139 _prologue->magic = (jint)0xc0c0feca;
140 _prologue->byte_order = PERFDATA_LITTLE_ENDIAN;
141 #else
142 _prologue->magic = (jint)0xcafec0c0;
143 _prologue->byte_order = PERFDATA_BIG_ENDIAN;
144 #endif
145
146 _prologue->major_version = PERFDATA_MAJOR_VERSION;
147 _prologue->minor_version = PERFDATA_MINOR_VERSION;
148 _prologue->accessible = 0;
149
150 _prologue->entry_offset = sizeof(PerfDataPrologue);
151 _prologue->num_entries = 0;
152 _prologue->used = 0;
153 _prologue->overflow = 0;
154 _prologue->mod_time_stamp = 0;
155
156 OrderAccess::release_store(&_initialized, 1);
157 }
158
159 void PerfMemory::destroy() {
160
161 if (_prologue == NULL) return;
162
163 if (_start != NULL && _prologue->overflow != 0) {
164
165 // This state indicates that the contiguous memory region exists and
166 // that it wasn't large enough to hold all the counters. In this case,
167 // we output a warning message to the user on exit if the -XX:+Verbose
168 // flag is set (a debug only flag). External monitoring tools can detect
169 // this condition by monitoring the _prologue->overflow word.
170 //
171 // There are two tunables that can help resolve this issue:
172 // - increase the size of the PerfMemory with -XX:PerfDataMemorySize=<n>
173 // - decrease the maximum string constant length with
174 // -XX:PerfMaxStringConstLength=<n>
175 //
176 if (PrintMiscellaneous && Verbose) {
177 warning("PerfMemory Overflow Occurred.\n"
178 "\tCapacity = " SIZE_FORMAT " bytes"
179 " Used = " SIZE_FORMAT " bytes"
180 " Overflow = " INT32_FORMAT " bytes"
181 "\n\tUse -XX:PerfDataMemorySize=<size> to specify larger size.",
182 PerfMemory::capacity(),
183 PerfMemory::used(),
184 _prologue->overflow);
185 }
186 }
187
188 if (_start != NULL) {
189
190 // this state indicates that the contiguous memory region was successfully
191 // and that persistent resources may need to be cleaned up. This is
192 // expected to be the typical condition.
193 //
194 delete_memory_region();
195 }
196
197 _start = NULL;
198 _end = NULL;
199 _top = NULL;
200 _prologue = NULL;
201 _capacity = 0;
202 }
203
204 // allocate an aligned block of memory from the PerfData memory
205 // region. This method assumes that the PerfData memory region
206 // was aligned on a double word boundary when created.
207 //
208 char* PerfMemory::alloc(size_t size) {
209
210 if (!UsePerfData) return NULL;
211
212 MutexLocker ml(PerfDataMemAlloc_lock);
213
214 assert(_prologue != NULL, "called before initialization");
215
216 // check that there is enough memory for this request
217 if ((_top + size) >= _end) {
218
219 _prologue->overflow += (jint)size;
220
221 return NULL;
222 }
223
224 char* result = _top;
225
226 _top += size;
227
228 assert(contains(result), "PerfData memory pointer out of range");
229
230 _prologue->used = (jint)used();
231 _prologue->num_entries = _prologue->num_entries + 1;
232
233 return result;
234 }
235
236 void PerfMemory::mark_updated() {
237 if (!UsePerfData) return;
238
239 _prologue->mod_time_stamp = os::elapsed_counter();
240 }
241
242 // Returns the complete path including the file name of performance data file.
243 // Caller is expected to release the allocated memory.
244 char* PerfMemory::get_perfdata_file_path() {
245 char* dest_file = NULL;
246
247 if (PerfDataSaveFile != NULL) {
248 // dest_file_name stores the validated file name if file_name
249 // contains %p which will be replaced by pid.
250 dest_file = NEW_C_HEAP_ARRAY(char, JVM_MAXPATHLEN, mtInternal);
251 if(!Arguments::copy_expand_pid(PerfDataSaveFile, strlen(PerfDataSaveFile),
252 dest_file, JVM_MAXPATHLEN)) {
253 FREE_C_HEAP_ARRAY(char, dest_file);
254 if (PrintMiscellaneous && Verbose) {
255 warning("Invalid performance data file path name specified, "\
256 "fall back to a default name");
257 }
258 } else {
259 return dest_file;
260 }
261 }
262 // create the name of the file for retaining the instrumentation memory.
263 dest_file = NEW_C_HEAP_ARRAY(char, PERFDATA_FILENAME_LEN, mtInternal);
264 jio_snprintf(dest_file, PERFDATA_FILENAME_LEN,
265 "%s_%d", PERFDATA_NAME, os::current_process_id());
266
267 return dest_file;
268 }