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 }