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