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