1 /* 2 * Copyright (c) 1997, 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 "jvm.h" 27 #include "classfile/classLoader.hpp" 28 #include "classfile/javaClasses.hpp" 29 #include "classfile/moduleEntry.hpp" 30 #include "classfile/systemDictionary.hpp" 31 #include "classfile/vmSymbols.hpp" 32 #include "code/codeCache.hpp" 33 #include "code/icBuffer.hpp" 34 #include "code/vtableStubs.hpp" 35 #include "gc/shared/vmGCOperations.hpp" 36 #include "interpreter/interpreter.hpp" 37 #include "logging/log.hpp" 38 #include "logging/logStream.hpp" 39 #include "memory/allocation.inline.hpp" 40 #ifdef ASSERT 41 #include "memory/guardedMemory.hpp" 42 #endif 43 #include "memory/resourceArea.hpp" 44 #include "oops/oop.inline.hpp" 45 #include "prims/jvm_misc.hpp" 46 #include "prims/privilegedStack.hpp" 47 #include "runtime/arguments.hpp" 48 #include "runtime/atomic.hpp" 49 #include "runtime/frame.inline.hpp" 50 #include "runtime/interfaceSupport.hpp" 51 #include "runtime/java.hpp" 52 #include "runtime/javaCalls.hpp" 53 #include "runtime/mutexLocker.hpp" 54 #include "runtime/os.inline.hpp" 55 #include "runtime/stubRoutines.hpp" 56 #include "runtime/thread.inline.hpp" 57 #include "runtime/vm_version.hpp" 58 #include "services/attachListener.hpp" 59 #include "services/mallocTracker.hpp" 60 #include "services/memTracker.hpp" 61 #include "services/nmtCommon.hpp" 62 #include "services/threadService.hpp" 63 #include "utilities/align.hpp" 64 #include "utilities/defaultStream.hpp" 65 #include "utilities/events.hpp" 66 67 # include <signal.h> 68 # include <errno.h> 69 70 OSThread* os::_starting_thread = NULL; 71 address os::_polling_page = NULL; 72 volatile int32_t* os::_mem_serialize_page = NULL; 73 uintptr_t os::_serialize_page_mask = 0; 74 volatile unsigned int os::_rand_seed = 1; 75 int os::_processor_count = 0; 76 int os::_initial_active_processor_count = 0; 77 size_t os::_page_sizes[os::page_sizes_max]; 78 79 #ifndef PRODUCT 80 julong os::num_mallocs = 0; // # of calls to malloc/realloc 81 julong os::alloc_bytes = 0; // # of bytes allocated 82 julong os::num_frees = 0; // # of calls to free 83 julong os::free_bytes = 0; // # of bytes freed 84 #endif 85 86 static juint cur_malloc_words = 0; // current size for MallocMaxTestWords 87 88 void os_init_globals() { 89 // Called from init_globals(). 90 // See Threads::create_vm() in thread.cpp, and init.cpp. 91 os::init_globals(); 92 } 93 94 // Fill in buffer with current local time as an ISO-8601 string. 95 // E.g., yyyy-mm-ddThh:mm:ss-zzzz. 96 // Returns buffer, or NULL if it failed. 97 // This would mostly be a call to 98 // strftime(...., "%Y-%m-%d" "T" "%H:%M:%S" "%z", ....) 99 // except that on Windows the %z behaves badly, so we do it ourselves. 100 // Also, people wanted milliseconds on there, 101 // and strftime doesn't do milliseconds. 102 char* os::iso8601_time(char* buffer, size_t buffer_length, bool utc) { 103 // Output will be of the form "YYYY-MM-DDThh:mm:ss.mmm+zzzz\0" 104 // 1 2 105 // 12345678901234567890123456789 106 // format string: "%04d-%02d-%02dT%02d:%02d:%02d.%03d%c%02d%02d" 107 static const size_t needed_buffer = 29; 108 109 // Sanity check the arguments 110 if (buffer == NULL) { 111 assert(false, "NULL buffer"); 112 return NULL; 113 } 114 if (buffer_length < needed_buffer) { 115 assert(false, "buffer_length too small"); 116 return NULL; 117 } 118 // Get the current time 119 jlong milliseconds_since_19700101 = javaTimeMillis(); 120 const int milliseconds_per_microsecond = 1000; 121 const time_t seconds_since_19700101 = 122 milliseconds_since_19700101 / milliseconds_per_microsecond; 123 const int milliseconds_after_second = 124 milliseconds_since_19700101 % milliseconds_per_microsecond; 125 // Convert the time value to a tm and timezone variable 126 struct tm time_struct; 127 if (utc) { 128 if (gmtime_pd(&seconds_since_19700101, &time_struct) == NULL) { 129 assert(false, "Failed gmtime_pd"); 130 return NULL; 131 } 132 } else { 133 if (localtime_pd(&seconds_since_19700101, &time_struct) == NULL) { 134 assert(false, "Failed localtime_pd"); 135 return NULL; 136 } 137 } 138 #if defined(_ALLBSD_SOURCE) 139 const time_t zone = (time_t) time_struct.tm_gmtoff; 140 #else 141 const time_t zone = timezone; 142 #endif 143 144 // If daylight savings time is in effect, 145 // we are 1 hour East of our time zone 146 const time_t seconds_per_minute = 60; 147 const time_t minutes_per_hour = 60; 148 const time_t seconds_per_hour = seconds_per_minute * minutes_per_hour; 149 time_t UTC_to_local = zone; 150 if (time_struct.tm_isdst > 0) { 151 UTC_to_local = UTC_to_local - seconds_per_hour; 152 } 153 154 // No offset when dealing with UTC 155 if (utc) { 156 UTC_to_local = 0; 157 } 158 159 // Compute the time zone offset. 160 // localtime_pd() sets timezone to the difference (in seconds) 161 // between UTC and and local time. 162 // ISO 8601 says we need the difference between local time and UTC, 163 // we change the sign of the localtime_pd() result. 164 const time_t local_to_UTC = -(UTC_to_local); 165 // Then we have to figure out if if we are ahead (+) or behind (-) UTC. 166 char sign_local_to_UTC = '+'; 167 time_t abs_local_to_UTC = local_to_UTC; 168 if (local_to_UTC < 0) { 169 sign_local_to_UTC = '-'; 170 abs_local_to_UTC = -(abs_local_to_UTC); 171 } 172 // Convert time zone offset seconds to hours and minutes. 173 const time_t zone_hours = (abs_local_to_UTC / seconds_per_hour); 174 const time_t zone_min = 175 ((abs_local_to_UTC % seconds_per_hour) / seconds_per_minute); 176 177 // Print an ISO 8601 date and time stamp into the buffer 178 const int year = 1900 + time_struct.tm_year; 179 const int month = 1 + time_struct.tm_mon; 180 const int printed = jio_snprintf(buffer, buffer_length, 181 "%04d-%02d-%02dT%02d:%02d:%02d.%03d%c%02d%02d", 182 year, 183 month, 184 time_struct.tm_mday, 185 time_struct.tm_hour, 186 time_struct.tm_min, 187 time_struct.tm_sec, 188 milliseconds_after_second, 189 sign_local_to_UTC, 190 zone_hours, 191 zone_min); 192 if (printed == 0) { 193 assert(false, "Failed jio_printf"); 194 return NULL; 195 } 196 return buffer; 197 } 198 199 OSReturn os::set_priority(Thread* thread, ThreadPriority p) { 200 #ifdef ASSERT 201 if (!(!thread->is_Java_thread() || 202 Thread::current() == thread || 203 Threads_lock->owned_by_self() 204 || thread->is_Compiler_thread() 205 )) { 206 assert(false, "possibility of dangling Thread pointer"); 207 } 208 #endif 209 210 if (p >= MinPriority && p <= MaxPriority) { 211 int priority = java_to_os_priority[p]; 212 return set_native_priority(thread, priority); 213 } else { 214 assert(false, "Should not happen"); 215 return OS_ERR; 216 } 217 } 218 219 // The mapping from OS priority back to Java priority may be inexact because 220 // Java priorities can map M:1 with native priorities. If you want the definite 221 // Java priority then use JavaThread::java_priority() 222 OSReturn os::get_priority(const Thread* const thread, ThreadPriority& priority) { 223 int p; 224 int os_prio; 225 OSReturn ret = get_native_priority(thread, &os_prio); 226 if (ret != OS_OK) return ret; 227 228 if (java_to_os_priority[MaxPriority] > java_to_os_priority[MinPriority]) { 229 for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] > os_prio; p--) ; 230 } else { 231 // niceness values are in reverse order 232 for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] < os_prio; p--) ; 233 } 234 priority = (ThreadPriority)p; 235 return OS_OK; 236 } 237 238 size_t os::committed_stack_size(address bottom, size_t size) { 239 #if defined(LINUX) || defined(_WINDOWS) 240 return pd_committed_stack_size(bottom, size); 241 #else 242 return size; 243 #endif 244 } 245 246 bool os::dll_build_name(char* buffer, size_t size, const char* fname) { 247 int n = jio_snprintf(buffer, size, "%s%s%s", JNI_LIB_PREFIX, fname, JNI_LIB_SUFFIX); 248 return (n != -1); 249 } 250 251 // Helper for dll_locate_lib. 252 // Pass buffer and printbuffer as we already printed the path to buffer 253 // when we called get_current_directory. This way we avoid another buffer 254 // of size MAX_PATH. 255 static bool conc_path_file_and_check(char *buffer, char *printbuffer, size_t printbuflen, 256 const char* pname, char lastchar, const char* fname) { 257 258 // Concatenate path and file name, but don't print double path separators. 259 const char *filesep = (WINDOWS_ONLY(lastchar == ':' ||) lastchar == os::file_separator()[0]) ? 260 "" : os::file_separator(); 261 int ret = jio_snprintf(printbuffer, printbuflen, "%s%s%s", pname, filesep, fname); 262 // Check whether file exists. 263 if (ret != -1) { 264 struct stat statbuf; 265 return os::stat(buffer, &statbuf) == 0; 266 } 267 return false; 268 } 269 270 bool os::dll_locate_lib(char *buffer, size_t buflen, 271 const char* pname, const char* fname) { 272 bool retval = false; 273 274 size_t fullfnamelen = strlen(JNI_LIB_PREFIX) + strlen(fname) + strlen(JNI_LIB_SUFFIX); 275 char* fullfname = (char*)NEW_C_HEAP_ARRAY(char, fullfnamelen + 1, mtInternal); 276 if (dll_build_name(fullfname, fullfnamelen + 1, fname)) { 277 const size_t pnamelen = pname ? strlen(pname) : 0; 278 279 if (pnamelen == 0) { 280 // If no path given, use current working directory. 281 const char* p = get_current_directory(buffer, buflen); 282 if (p != NULL) { 283 const size_t plen = strlen(buffer); 284 const char lastchar = buffer[plen - 1]; 285 retval = conc_path_file_and_check(buffer, &buffer[plen], buflen - plen, 286 "", lastchar, fullfname); 287 } 288 } else if (strchr(pname, *os::path_separator()) != NULL) { 289 // A list of paths. Search for the path that contains the library. 290 int n; 291 char** pelements = split_path(pname, &n); 292 if (pelements != NULL) { 293 for (int i = 0; i < n; i++) { 294 char* path = pelements[i]; 295 // Really shouldn't be NULL, but check can't hurt. 296 size_t plen = (path == NULL) ? 0 : strlen(path); 297 if (plen == 0) { 298 continue; // Skip the empty path values. 299 } 300 const char lastchar = path[plen - 1]; 301 retval = conc_path_file_and_check(buffer, buffer, buflen, path, lastchar, fullfname); 302 if (retval) break; 303 } 304 // Release the storage allocated by split_path. 305 for (int i = 0; i < n; i++) { 306 if (pelements[i] != NULL) { 307 FREE_C_HEAP_ARRAY(char, pelements[i]); 308 } 309 } 310 FREE_C_HEAP_ARRAY(char*, pelements); 311 } 312 } else { 313 // A definite path. 314 const char lastchar = pname[pnamelen-1]; 315 retval = conc_path_file_and_check(buffer, buffer, buflen, pname, lastchar, fullfname); 316 } 317 } 318 319 FREE_C_HEAP_ARRAY(char*, fullfname); 320 return retval; 321 } 322 323 // --------------------- sun.misc.Signal (optional) --------------------- 324 325 326 // SIGBREAK is sent by the keyboard to query the VM state 327 #ifndef SIGBREAK 328 #define SIGBREAK SIGQUIT 329 #endif 330 331 // sigexitnum_pd is a platform-specific special signal used for terminating the Signal thread. 332 333 334 static void signal_thread_entry(JavaThread* thread, TRAPS) { 335 os::set_priority(thread, NearMaxPriority); 336 while (true) { 337 int sig; 338 { 339 // FIXME : Currently we have not decided what should be the status 340 // for this java thread blocked here. Once we decide about 341 // that we should fix this. 342 sig = os::signal_wait(); 343 } 344 if (sig == os::sigexitnum_pd()) { 345 // Terminate the signal thread 346 return; 347 } 348 349 switch (sig) { 350 case SIGBREAK: { 351 // Check if the signal is a trigger to start the Attach Listener - in that 352 // case don't print stack traces. 353 if (!DisableAttachMechanism && AttachListener::is_init_trigger()) { 354 continue; 355 } 356 // Print stack traces 357 // Any SIGBREAK operations added here should make sure to flush 358 // the output stream (e.g. tty->flush()) after output. See 4803766. 359 // Each module also prints an extra carriage return after its output. 360 VM_PrintThreads op; 361 VMThread::execute(&op); 362 VM_PrintJNI jni_op; 363 VMThread::execute(&jni_op); 364 VM_FindDeadlocks op1(tty); 365 VMThread::execute(&op1); 366 Universe::print_heap_at_SIGBREAK(); 367 if (PrintClassHistogram) { 368 VM_GC_HeapInspection op1(tty, true /* force full GC before heap inspection */); 369 VMThread::execute(&op1); 370 } 371 if (JvmtiExport::should_post_data_dump()) { 372 JvmtiExport::post_data_dump(); 373 } 374 break; 375 } 376 default: { 377 // Dispatch the signal to java 378 HandleMark hm(THREAD); 379 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_misc_Signal(), THREAD); 380 if (klass != NULL) { 381 JavaValue result(T_VOID); 382 JavaCallArguments args; 383 args.push_int(sig); 384 JavaCalls::call_static( 385 &result, 386 klass, 387 vmSymbols::dispatch_name(), 388 vmSymbols::int_void_signature(), 389 &args, 390 THREAD 391 ); 392 } 393 if (HAS_PENDING_EXCEPTION) { 394 // tty is initialized early so we don't expect it to be null, but 395 // if it is we can't risk doing an initialization that might 396 // trigger additional out-of-memory conditions 397 if (tty != NULL) { 398 char klass_name[256]; 399 char tmp_sig_name[16]; 400 const char* sig_name = "UNKNOWN"; 401 InstanceKlass::cast(PENDING_EXCEPTION->klass())-> 402 name()->as_klass_external_name(klass_name, 256); 403 if (os::exception_name(sig, tmp_sig_name, 16) != NULL) 404 sig_name = tmp_sig_name; 405 warning("Exception %s occurred dispatching signal %s to handler" 406 "- the VM may need to be forcibly terminated", 407 klass_name, sig_name ); 408 } 409 CLEAR_PENDING_EXCEPTION; 410 } 411 } 412 } 413 } 414 } 415 416 void os::init_before_ergo() { 417 initialize_initial_active_processor_count(); 418 // We need to initialize large page support here because ergonomics takes some 419 // decisions depending on large page support and the calculated large page size. 420 large_page_init(); 421 422 // We need to adapt the configured number of stack protection pages given 423 // in 4K pages to the actual os page size. We must do this before setting 424 // up minimal stack sizes etc. in os::init_2(). 425 JavaThread::set_stack_red_zone_size (align_up(StackRedPages * 4 * K, vm_page_size())); 426 JavaThread::set_stack_yellow_zone_size (align_up(StackYellowPages * 4 * K, vm_page_size())); 427 JavaThread::set_stack_reserved_zone_size(align_up(StackReservedPages * 4 * K, vm_page_size())); 428 JavaThread::set_stack_shadow_zone_size (align_up(StackShadowPages * 4 * K, vm_page_size())); 429 430 // VM version initialization identifies some characteristics of the 431 // platform that are used during ergonomic decisions. 432 VM_Version::init_before_ergo(); 433 } 434 435 void os::signal_init(TRAPS) { 436 if (!ReduceSignalUsage) { 437 // Setup JavaThread for processing signals 438 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); 439 InstanceKlass* ik = InstanceKlass::cast(k); 440 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK); 441 442 const char thread_name[] = "Signal Dispatcher"; 443 Handle string = java_lang_String::create_from_str(thread_name, CHECK); 444 445 // Initialize thread_oop to put it into the system threadGroup 446 Handle thread_group (THREAD, Universe::system_thread_group()); 447 JavaValue result(T_VOID); 448 JavaCalls::call_special(&result, thread_oop, 449 ik, 450 vmSymbols::object_initializer_name(), 451 vmSymbols::threadgroup_string_void_signature(), 452 thread_group, 453 string, 454 CHECK); 455 456 Klass* group = SystemDictionary::ThreadGroup_klass(); 457 JavaCalls::call_special(&result, 458 thread_group, 459 group, 460 vmSymbols::add_method_name(), 461 vmSymbols::thread_void_signature(), 462 thread_oop, // ARG 1 463 CHECK); 464 465 os::signal_init_pd(); 466 467 { MutexLocker mu(Threads_lock); 468 JavaThread* signal_thread = new JavaThread(&signal_thread_entry); 469 470 // At this point it may be possible that no osthread was created for the 471 // JavaThread due to lack of memory. We would have to throw an exception 472 // in that case. However, since this must work and we do not allow 473 // exceptions anyway, check and abort if this fails. 474 if (signal_thread == NULL || signal_thread->osthread() == NULL) { 475 vm_exit_during_initialization("java.lang.OutOfMemoryError", 476 os::native_thread_creation_failed_msg()); 477 } 478 479 java_lang_Thread::set_thread(thread_oop(), signal_thread); 480 java_lang_Thread::set_priority(thread_oop(), NearMaxPriority); 481 java_lang_Thread::set_daemon(thread_oop()); 482 483 signal_thread->set_threadObj(thread_oop()); 484 Threads::add(signal_thread); 485 Thread::start(signal_thread); 486 } 487 // Handle ^BREAK 488 os::signal(SIGBREAK, os::user_handler()); 489 } 490 } 491 492 493 void os::terminate_signal_thread() { 494 if (!ReduceSignalUsage) 495 signal_notify(sigexitnum_pd()); 496 } 497 498 499 // --------------------- loading libraries --------------------- 500 501 typedef jint (JNICALL *JNI_OnLoad_t)(JavaVM *, void *); 502 extern struct JavaVM_ main_vm; 503 504 static void* _native_java_library = NULL; 505 506 void* os::native_java_library() { 507 if (_native_java_library == NULL) { 508 char buffer[JVM_MAXPATHLEN]; 509 char ebuf[1024]; 510 511 // Try to load verify dll first. In 1.3 java dll depends on it and is not 512 // always able to find it when the loading executable is outside the JDK. 513 // In order to keep working with 1.2 we ignore any loading errors. 514 if (dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(), 515 "verify")) { 516 dll_load(buffer, ebuf, sizeof(ebuf)); 517 } 518 519 // Load java dll 520 if (dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(), 521 "java")) { 522 _native_java_library = dll_load(buffer, ebuf, sizeof(ebuf)); 523 } 524 if (_native_java_library == NULL) { 525 vm_exit_during_initialization("Unable to load native library", ebuf); 526 } 527 528 #if defined(__OpenBSD__) 529 // Work-around OpenBSD's lack of $ORIGIN support by pre-loading libnet.so 530 // ignore errors 531 if (dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(), 532 "net")) { 533 dll_load(buffer, ebuf, sizeof(ebuf)); 534 } 535 #endif 536 } 537 return _native_java_library; 538 } 539 540 /* 541 * Support for finding Agent_On(Un)Load/Attach<_lib_name> if it exists. 542 * If check_lib == true then we are looking for an 543 * Agent_OnLoad_lib_name or Agent_OnAttach_lib_name function to determine if 544 * this library is statically linked into the image. 545 * If check_lib == false then we will look for the appropriate symbol in the 546 * executable if agent_lib->is_static_lib() == true or in the shared library 547 * referenced by 'handle'. 548 */ 549 void* os::find_agent_function(AgentLibrary *agent_lib, bool check_lib, 550 const char *syms[], size_t syms_len) { 551 assert(agent_lib != NULL, "sanity check"); 552 const char *lib_name; 553 void *handle = agent_lib->os_lib(); 554 void *entryName = NULL; 555 char *agent_function_name; 556 size_t i; 557 558 // If checking then use the agent name otherwise test is_static_lib() to 559 // see how to process this lookup 560 lib_name = ((check_lib || agent_lib->is_static_lib()) ? agent_lib->name() : NULL); 561 for (i = 0; i < syms_len; i++) { 562 agent_function_name = build_agent_function_name(syms[i], lib_name, agent_lib->is_absolute_path()); 563 if (agent_function_name == NULL) { 564 break; 565 } 566 entryName = dll_lookup(handle, agent_function_name); 567 FREE_C_HEAP_ARRAY(char, agent_function_name); 568 if (entryName != NULL) { 569 break; 570 } 571 } 572 return entryName; 573 } 574 575 // See if the passed in agent is statically linked into the VM image. 576 bool os::find_builtin_agent(AgentLibrary *agent_lib, const char *syms[], 577 size_t syms_len) { 578 void *ret; 579 void *proc_handle; 580 void *save_handle; 581 582 assert(agent_lib != NULL, "sanity check"); 583 if (agent_lib->name() == NULL) { 584 return false; 585 } 586 proc_handle = get_default_process_handle(); 587 // Check for Agent_OnLoad/Attach_lib_name function 588 save_handle = agent_lib->os_lib(); 589 // We want to look in this process' symbol table. 590 agent_lib->set_os_lib(proc_handle); 591 ret = find_agent_function(agent_lib, true, syms, syms_len); 592 if (ret != NULL) { 593 // Found an entry point like Agent_OnLoad_lib_name so we have a static agent 594 agent_lib->set_valid(); 595 agent_lib->set_static_lib(true); 596 return true; 597 } 598 agent_lib->set_os_lib(save_handle); 599 return false; 600 } 601 602 // --------------------- heap allocation utilities --------------------- 603 604 char *os::strdup(const char *str, MEMFLAGS flags) { 605 size_t size = strlen(str); 606 char *dup_str = (char *)malloc(size + 1, flags); 607 if (dup_str == NULL) return NULL; 608 strcpy(dup_str, str); 609 return dup_str; 610 } 611 612 char* os::strdup_check_oom(const char* str, MEMFLAGS flags) { 613 char* p = os::strdup(str, flags); 614 if (p == NULL) { 615 vm_exit_out_of_memory(strlen(str) + 1, OOM_MALLOC_ERROR, "os::strdup_check_oom"); 616 } 617 return p; 618 } 619 620 621 #define paranoid 0 /* only set to 1 if you suspect checking code has bug */ 622 623 #ifdef ASSERT 624 625 static void verify_memory(void* ptr) { 626 GuardedMemory guarded(ptr); 627 if (!guarded.verify_guards()) { 628 tty->print_cr("## nof_mallocs = " UINT64_FORMAT ", nof_frees = " UINT64_FORMAT, os::num_mallocs, os::num_frees); 629 tty->print_cr("## memory stomp:"); 630 guarded.print_on(tty); 631 fatal("memory stomping error"); 632 } 633 } 634 635 #endif 636 637 // 638 // This function supports testing of the malloc out of memory 639 // condition without really running the system out of memory. 640 // 641 static bool has_reached_max_malloc_test_peak(size_t alloc_size) { 642 if (MallocMaxTestWords > 0) { 643 jint words = (jint)(alloc_size / BytesPerWord); 644 645 if ((cur_malloc_words + words) > MallocMaxTestWords) { 646 return true; 647 } 648 Atomic::add(words, (volatile jint *)&cur_malloc_words); 649 } 650 return false; 651 } 652 653 void* os::malloc(size_t size, MEMFLAGS flags) { 654 return os::malloc(size, flags, CALLER_PC); 655 } 656 657 void* os::malloc(size_t size, MEMFLAGS memflags, const NativeCallStack& stack) { 658 NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1)); 659 NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size)); 660 661 // Since os::malloc can be called when the libjvm.{dll,so} is 662 // first loaded and we don't have a thread yet we must accept NULL also here. 663 assert(!os::ThreadCrashProtection::is_crash_protected(Thread::current_or_null()), 664 "malloc() not allowed when crash protection is set"); 665 666 if (size == 0) { 667 // return a valid pointer if size is zero 668 // if NULL is returned the calling functions assume out of memory. 669 size = 1; 670 } 671 672 // NMT support 673 NMT_TrackingLevel level = MemTracker::tracking_level(); 674 size_t nmt_header_size = MemTracker::malloc_header_size(level); 675 676 #ifndef ASSERT 677 const size_t alloc_size = size + nmt_header_size; 678 #else 679 const size_t alloc_size = GuardedMemory::get_total_size(size + nmt_header_size); 680 if (size + nmt_header_size > alloc_size) { // Check for rollover. 681 return NULL; 682 } 683 #endif 684 685 // For the test flag -XX:MallocMaxTestWords 686 if (has_reached_max_malloc_test_peak(size)) { 687 return NULL; 688 } 689 690 u_char* ptr; 691 ptr = (u_char*)::malloc(alloc_size); 692 693 #ifdef ASSERT 694 if (ptr == NULL) { 695 return NULL; 696 } 697 // Wrap memory with guard 698 GuardedMemory guarded(ptr, size + nmt_header_size); 699 ptr = guarded.get_user_ptr(); 700 #endif 701 if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) { 702 tty->print_cr("os::malloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, p2i(ptr)); 703 breakpoint(); 704 } 705 debug_only(if (paranoid) verify_memory(ptr)); 706 if (PrintMalloc && tty != NULL) { 707 tty->print_cr("os::malloc " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, p2i(ptr)); 708 } 709 710 // we do not track guard memory 711 return MemTracker::record_malloc((address)ptr, size, memflags, stack, level); 712 } 713 714 void* os::realloc(void *memblock, size_t size, MEMFLAGS flags) { 715 return os::realloc(memblock, size, flags, CALLER_PC); 716 } 717 718 void* os::realloc(void *memblock, size_t size, MEMFLAGS memflags, const NativeCallStack& stack) { 719 720 // For the test flag -XX:MallocMaxTestWords 721 if (has_reached_max_malloc_test_peak(size)) { 722 return NULL; 723 } 724 725 if (size == 0) { 726 // return a valid pointer if size is zero 727 // if NULL is returned the calling functions assume out of memory. 728 size = 1; 729 } 730 731 #ifndef ASSERT 732 NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1)); 733 NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size)); 734 // NMT support 735 void* membase = MemTracker::record_free(memblock); 736 NMT_TrackingLevel level = MemTracker::tracking_level(); 737 size_t nmt_header_size = MemTracker::malloc_header_size(level); 738 void* ptr = ::realloc(membase, size + nmt_header_size); 739 return MemTracker::record_malloc(ptr, size, memflags, stack, level); 740 #else 741 if (memblock == NULL) { 742 return os::malloc(size, memflags, stack); 743 } 744 if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) { 745 tty->print_cr("os::realloc caught " PTR_FORMAT, p2i(memblock)); 746 breakpoint(); 747 } 748 // NMT support 749 void* membase = MemTracker::malloc_base(memblock); 750 verify_memory(membase); 751 // always move the block 752 void* ptr = os::malloc(size, memflags, stack); 753 if (PrintMalloc && tty != NULL) { 754 tty->print_cr("os::realloc " SIZE_FORMAT " bytes, " PTR_FORMAT " --> " PTR_FORMAT, size, p2i(memblock), p2i(ptr)); 755 } 756 // Copy to new memory if malloc didn't fail 757 if ( ptr != NULL ) { 758 GuardedMemory guarded(MemTracker::malloc_base(memblock)); 759 // Guard's user data contains NMT header 760 size_t memblock_size = guarded.get_user_size() - MemTracker::malloc_header_size(memblock); 761 memcpy(ptr, memblock, MIN2(size, memblock_size)); 762 if (paranoid) verify_memory(MemTracker::malloc_base(ptr)); 763 if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) { 764 tty->print_cr("os::realloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, p2i(ptr)); 765 breakpoint(); 766 } 767 os::free(memblock); 768 } 769 return ptr; 770 #endif 771 } 772 773 774 void os::free(void *memblock) { 775 NOT_PRODUCT(inc_stat_counter(&num_frees, 1)); 776 #ifdef ASSERT 777 if (memblock == NULL) return; 778 if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) { 779 if (tty != NULL) tty->print_cr("os::free caught " PTR_FORMAT, p2i(memblock)); 780 breakpoint(); 781 } 782 void* membase = MemTracker::record_free(memblock); 783 verify_memory(membase); 784 785 GuardedMemory guarded(membase); 786 size_t size = guarded.get_user_size(); 787 inc_stat_counter(&free_bytes, size); 788 membase = guarded.release_for_freeing(); 789 if (PrintMalloc && tty != NULL) { 790 fprintf(stderr, "os::free " SIZE_FORMAT " bytes --> " PTR_FORMAT "\n", size, (uintptr_t)membase); 791 } 792 ::free(membase); 793 #else 794 void* membase = MemTracker::record_free(memblock); 795 ::free(membase); 796 #endif 797 } 798 799 void os::init_random(unsigned int initval) { 800 _rand_seed = initval; 801 } 802 803 804 static int random_helper(unsigned int rand_seed) { 805 /* standard, well-known linear congruential random generator with 806 * next_rand = (16807*seed) mod (2**31-1) 807 * see 808 * (1) "Random Number Generators: Good Ones Are Hard to Find", 809 * S.K. Park and K.W. Miller, Communications of the ACM 31:10 (Oct 1988), 810 * (2) "Two Fast Implementations of the 'Minimal Standard' Random 811 * Number Generator", David G. Carta, Comm. ACM 33, 1 (Jan 1990), pp. 87-88. 812 */ 813 const unsigned int a = 16807; 814 const unsigned int m = 2147483647; 815 const int q = m / a; assert(q == 127773, "weird math"); 816 const int r = m % a; assert(r == 2836, "weird math"); 817 818 // compute az=2^31p+q 819 unsigned int lo = a * (rand_seed & 0xFFFF); 820 unsigned int hi = a * (rand_seed >> 16); 821 lo += (hi & 0x7FFF) << 16; 822 823 // if q overflowed, ignore the overflow and increment q 824 if (lo > m) { 825 lo &= m; 826 ++lo; 827 } 828 lo += hi >> 15; 829 830 // if (p+q) overflowed, ignore the overflow and increment (p+q) 831 if (lo > m) { 832 lo &= m; 833 ++lo; 834 } 835 return lo; 836 } 837 838 int os::random() { 839 // Make updating the random seed thread safe. 840 while (true) { 841 unsigned int seed = _rand_seed; 842 unsigned int rand = random_helper(seed); 843 if (Atomic::cmpxchg(rand, &_rand_seed, seed) == seed) { 844 return static_cast<int>(rand); 845 } 846 } 847 } 848 849 // The INITIALIZED state is distinguished from the SUSPENDED state because the 850 // conditions in which a thread is first started are different from those in which 851 // a suspension is resumed. These differences make it hard for us to apply the 852 // tougher checks when starting threads that we want to do when resuming them. 853 // However, when start_thread is called as a result of Thread.start, on a Java 854 // thread, the operation is synchronized on the Java Thread object. So there 855 // cannot be a race to start the thread and hence for the thread to exit while 856 // we are working on it. Non-Java threads that start Java threads either have 857 // to do so in a context in which races are impossible, or should do appropriate 858 // locking. 859 860 void os::start_thread(Thread* thread) { 861 // guard suspend/resume 862 MutexLockerEx ml(thread->SR_lock(), Mutex::_no_safepoint_check_flag); 863 OSThread* osthread = thread->osthread(); 864 osthread->set_state(RUNNABLE); 865 pd_start_thread(thread); 866 } 867 868 void os::abort(bool dump_core) { 869 abort(dump_core && CreateCoredumpOnCrash, NULL, NULL); 870 } 871 872 //--------------------------------------------------------------------------- 873 // Helper functions for fatal error handler 874 875 void os::print_hex_dump(outputStream* st, address start, address end, int unitsize) { 876 assert(unitsize == 1 || unitsize == 2 || unitsize == 4 || unitsize == 8, "just checking"); 877 878 int cols = 0; 879 int cols_per_line = 0; 880 switch (unitsize) { 881 case 1: cols_per_line = 16; break; 882 case 2: cols_per_line = 8; break; 883 case 4: cols_per_line = 4; break; 884 case 8: cols_per_line = 2; break; 885 default: return; 886 } 887 888 address p = start; 889 st->print(PTR_FORMAT ": ", p2i(start)); 890 while (p < end) { 891 switch (unitsize) { 892 case 1: st->print("%02x", *(u1*)p); break; 893 case 2: st->print("%04x", *(u2*)p); break; 894 case 4: st->print("%08x", *(u4*)p); break; 895 case 8: st->print("%016" FORMAT64_MODIFIER "x", *(u8*)p); break; 896 } 897 p += unitsize; 898 cols++; 899 if (cols >= cols_per_line && p < end) { 900 cols = 0; 901 st->cr(); 902 st->print(PTR_FORMAT ": ", p2i(p)); 903 } else { 904 st->print(" "); 905 } 906 } 907 st->cr(); 908 } 909 910 void os::print_environment_variables(outputStream* st, const char** env_list) { 911 if (env_list) { 912 st->print_cr("Environment Variables:"); 913 914 for (int i = 0; env_list[i] != NULL; i++) { 915 char *envvar = ::getenv(env_list[i]); 916 if (envvar != NULL) { 917 st->print("%s", env_list[i]); 918 st->print("="); 919 st->print_cr("%s", envvar); 920 } 921 } 922 } 923 } 924 925 void os::print_cpu_info(outputStream* st, char* buf, size_t buflen) { 926 // cpu 927 st->print("CPU:"); 928 st->print("total %d", os::processor_count()); 929 // It's not safe to query number of active processors after crash 930 // st->print("(active %d)", os::active_processor_count()); but we can 931 // print the initial number of active processors. 932 // We access the raw value here because the assert in the accessor will 933 // fail if the crash occurs before initialization of this value. 934 st->print(" (initial active %d)", _initial_active_processor_count); 935 st->print(" %s", VM_Version::features_string()); 936 st->cr(); 937 pd_print_cpu_info(st, buf, buflen); 938 } 939 940 // Print a one line string summarizing the cpu, number of cores, memory, and operating system version 941 void os::print_summary_info(outputStream* st, char* buf, size_t buflen) { 942 st->print("Host: "); 943 #ifndef PRODUCT 944 if (get_host_name(buf, buflen)) { 945 st->print("%s, ", buf); 946 } 947 #endif // PRODUCT 948 get_summary_cpu_info(buf, buflen); 949 st->print("%s, ", buf); 950 size_t mem = physical_memory()/G; 951 if (mem == 0) { // for low memory systems 952 mem = physical_memory()/M; 953 st->print("%d cores, " SIZE_FORMAT "M, ", processor_count(), mem); 954 } else { 955 st->print("%d cores, " SIZE_FORMAT "G, ", processor_count(), mem); 956 } 957 get_summary_os_info(buf, buflen); 958 st->print_raw(buf); 959 st->cr(); 960 } 961 962 void os::print_date_and_time(outputStream *st, char* buf, size_t buflen) { 963 const int secs_per_day = 86400; 964 const int secs_per_hour = 3600; 965 const int secs_per_min = 60; 966 967 time_t tloc; 968 (void)time(&tloc); 969 char* timestring = ctime(&tloc); // ctime adds newline. 970 // edit out the newline 971 char* nl = strchr(timestring, '\n'); 972 if (nl != NULL) { 973 *nl = '\0'; 974 } 975 976 struct tm tz; 977 if (localtime_pd(&tloc, &tz) != NULL) { 978 ::strftime(buf, buflen, "%Z", &tz); 979 st->print("Time: %s %s", timestring, buf); 980 } else { 981 st->print("Time: %s", timestring); 982 } 983 984 double t = os::elapsedTime(); 985 // NOTE: It tends to crash after a SEGV if we want to printf("%f",...) in 986 // Linux. Must be a bug in glibc ? Workaround is to round "t" to int 987 // before printf. We lost some precision, but who cares? 988 int eltime = (int)t; // elapsed time in seconds 989 990 // print elapsed time in a human-readable format: 991 int eldays = eltime / secs_per_day; 992 int day_secs = eldays * secs_per_day; 993 int elhours = (eltime - day_secs) / secs_per_hour; 994 int hour_secs = elhours * secs_per_hour; 995 int elmins = (eltime - day_secs - hour_secs) / secs_per_min; 996 int minute_secs = elmins * secs_per_min; 997 int elsecs = (eltime - day_secs - hour_secs - minute_secs); 998 st->print_cr(" elapsed time: %d seconds (%dd %dh %dm %ds)", eltime, eldays, elhours, elmins, elsecs); 999 } 1000 1001 // moved from debug.cpp (used to be find()) but still called from there 1002 // The verbose parameter is only set by the debug code in one case 1003 void os::print_location(outputStream* st, intptr_t x, bool verbose) { 1004 address addr = (address)x; 1005 CodeBlob* b = CodeCache::find_blob_unsafe(addr); 1006 if (b != NULL) { 1007 if (b->is_buffer_blob()) { 1008 // the interpreter is generated into a buffer blob 1009 InterpreterCodelet* i = Interpreter::codelet_containing(addr); 1010 if (i != NULL) { 1011 st->print_cr(INTPTR_FORMAT " is at code_begin+%d in an Interpreter codelet", p2i(addr), (int)(addr - i->code_begin())); 1012 i->print_on(st); 1013 return; 1014 } 1015 if (Interpreter::contains(addr)) { 1016 st->print_cr(INTPTR_FORMAT " is pointing into interpreter code" 1017 " (not bytecode specific)", p2i(addr)); 1018 return; 1019 } 1020 // 1021 if (AdapterHandlerLibrary::contains(b)) { 1022 st->print_cr(INTPTR_FORMAT " is at code_begin+%d in an AdapterHandler", p2i(addr), (int)(addr - b->code_begin())); 1023 AdapterHandlerLibrary::print_handler_on(st, b); 1024 } 1025 // the stubroutines are generated into a buffer blob 1026 StubCodeDesc* d = StubCodeDesc::desc_for(addr); 1027 if (d != NULL) { 1028 st->print_cr(INTPTR_FORMAT " is at begin+%d in a stub", p2i(addr), (int)(addr - d->begin())); 1029 d->print_on(st); 1030 st->cr(); 1031 return; 1032 } 1033 if (StubRoutines::contains(addr)) { 1034 st->print_cr(INTPTR_FORMAT " is pointing to an (unnamed) stub routine", p2i(addr)); 1035 return; 1036 } 1037 // the InlineCacheBuffer is using stubs generated into a buffer blob 1038 if (InlineCacheBuffer::contains(addr)) { 1039 st->print_cr(INTPTR_FORMAT " is pointing into InlineCacheBuffer", p2i(addr)); 1040 return; 1041 } 1042 VtableStub* v = VtableStubs::stub_containing(addr); 1043 if (v != NULL) { 1044 st->print_cr(INTPTR_FORMAT " is at entry_point+%d in a vtable stub", p2i(addr), (int)(addr - v->entry_point())); 1045 v->print_on(st); 1046 st->cr(); 1047 return; 1048 } 1049 } 1050 nmethod* nm = b->as_nmethod_or_null(); 1051 if (nm != NULL) { 1052 ResourceMark rm; 1053 st->print(INTPTR_FORMAT " is at entry_point+%d in (nmethod*)" INTPTR_FORMAT, 1054 p2i(addr), (int)(addr - nm->entry_point()), p2i(nm)); 1055 if (verbose) { 1056 st->print(" for "); 1057 nm->method()->print_value_on(st); 1058 } 1059 st->cr(); 1060 nm->print_nmethod(verbose); 1061 return; 1062 } 1063 st->print_cr(INTPTR_FORMAT " is at code_begin+%d in ", p2i(addr), (int)(addr - b->code_begin())); 1064 b->print_on(st); 1065 return; 1066 } 1067 1068 if (Universe::heap()->is_in(addr)) { 1069 HeapWord* p = Universe::heap()->block_start(addr); 1070 bool print = false; 1071 // If we couldn't find it it just may mean that heap wasn't parsable 1072 // See if we were just given an oop directly 1073 if (p != NULL && Universe::heap()->block_is_obj(p)) { 1074 print = true; 1075 } else if (p == NULL && oopDesc::is_oop(oop(addr))) { 1076 p = (HeapWord*) addr; 1077 print = true; 1078 } 1079 if (print) { 1080 if (p == (HeapWord*) addr) { 1081 st->print_cr(INTPTR_FORMAT " is an oop", p2i(addr)); 1082 } else { 1083 st->print_cr(INTPTR_FORMAT " is pointing into object: " INTPTR_FORMAT, p2i(addr), p2i(p)); 1084 } 1085 oop(p)->print_on(st); 1086 return; 1087 } 1088 } else { 1089 if (Universe::heap()->is_in_reserved(addr)) { 1090 st->print_cr(INTPTR_FORMAT " is an unallocated location " 1091 "in the heap", p2i(addr)); 1092 return; 1093 } 1094 } 1095 if (JNIHandles::is_global_handle((jobject) addr)) { 1096 st->print_cr(INTPTR_FORMAT " is a global jni handle", p2i(addr)); 1097 return; 1098 } 1099 if (JNIHandles::is_weak_global_handle((jobject) addr)) { 1100 st->print_cr(INTPTR_FORMAT " is a weak global jni handle", p2i(addr)); 1101 return; 1102 } 1103 #ifndef PRODUCT 1104 // we don't keep the block list in product mode 1105 if (JNIHandleBlock::any_contains((jobject) addr)) { 1106 st->print_cr(INTPTR_FORMAT " is a local jni handle", p2i(addr)); 1107 return; 1108 } 1109 #endif 1110 1111 for(JavaThread *thread = Threads::first(); thread; thread = thread->next()) { 1112 // Check for privilege stack 1113 if (thread->privileged_stack_top() != NULL && 1114 thread->privileged_stack_top()->contains(addr)) { 1115 st->print_cr(INTPTR_FORMAT " is pointing into the privilege stack " 1116 "for thread: " INTPTR_FORMAT, p2i(addr), p2i(thread)); 1117 if (verbose) thread->print_on(st); 1118 return; 1119 } 1120 // If the addr is a java thread print information about that. 1121 if (addr == (address)thread) { 1122 if (verbose) { 1123 thread->print_on(st); 1124 } else { 1125 st->print_cr(INTPTR_FORMAT " is a thread", p2i(addr)); 1126 } 1127 return; 1128 } 1129 // If the addr is in the stack region for this thread then report that 1130 // and print thread info 1131 if (thread->on_local_stack(addr)) { 1132 st->print_cr(INTPTR_FORMAT " is pointing into the stack for thread: " 1133 INTPTR_FORMAT, p2i(addr), p2i(thread)); 1134 if (verbose) thread->print_on(st); 1135 return; 1136 } 1137 1138 } 1139 1140 // Check if in metaspace and print types that have vptrs (only method now) 1141 if (Metaspace::contains(addr)) { 1142 if (Method::has_method_vptr((const void*)addr)) { 1143 ((Method*)addr)->print_value_on(st); 1144 st->cr(); 1145 } else { 1146 // Use addr->print() from the debugger instead (not here) 1147 st->print_cr(INTPTR_FORMAT " is pointing into metadata", p2i(addr)); 1148 } 1149 return; 1150 } 1151 1152 // Try an OS specific find 1153 if (os::find(addr, st)) { 1154 return; 1155 } 1156 1157 st->print_cr(INTPTR_FORMAT " is an unknown value", p2i(addr)); 1158 } 1159 1160 // Looks like all platforms except IA64 can use the same function to check 1161 // if C stack is walkable beyond current frame. The check for fp() is not 1162 // necessary on Sparc, but it's harmless. 1163 bool os::is_first_C_frame(frame* fr) { 1164 #if (defined(IA64) && !defined(AIX)) && !defined(_WIN32) 1165 // On IA64 we have to check if the callers bsp is still valid 1166 // (i.e. within the register stack bounds). 1167 // Notice: this only works for threads created by the VM and only if 1168 // we walk the current stack!!! If we want to be able to walk 1169 // arbitrary other threads, we'll have to somehow store the thread 1170 // object in the frame. 1171 Thread *thread = Thread::current(); 1172 if ((address)fr->fp() <= 1173 thread->register_stack_base() HPUX_ONLY(+ 0x0) LINUX_ONLY(+ 0x50)) { 1174 // This check is a little hacky, because on Linux the first C 1175 // frame's ('start_thread') register stack frame starts at 1176 // "register_stack_base + 0x48" while on HPUX, the first C frame's 1177 // ('__pthread_bound_body') register stack frame seems to really 1178 // start at "register_stack_base". 1179 return true; 1180 } else { 1181 return false; 1182 } 1183 #elif defined(IA64) && defined(_WIN32) 1184 return true; 1185 #else 1186 // Load up sp, fp, sender sp and sender fp, check for reasonable values. 1187 // Check usp first, because if that's bad the other accessors may fault 1188 // on some architectures. Ditto ufp second, etc. 1189 uintptr_t fp_align_mask = (uintptr_t)(sizeof(address)-1); 1190 // sp on amd can be 32 bit aligned. 1191 uintptr_t sp_align_mask = (uintptr_t)(sizeof(int)-1); 1192 1193 uintptr_t usp = (uintptr_t)fr->sp(); 1194 if ((usp & sp_align_mask) != 0) return true; 1195 1196 uintptr_t ufp = (uintptr_t)fr->fp(); 1197 if ((ufp & fp_align_mask) != 0) return true; 1198 1199 uintptr_t old_sp = (uintptr_t)fr->sender_sp(); 1200 if ((old_sp & sp_align_mask) != 0) return true; 1201 if (old_sp == 0 || old_sp == (uintptr_t)-1) return true; 1202 1203 uintptr_t old_fp = (uintptr_t)fr->link(); 1204 if ((old_fp & fp_align_mask) != 0) return true; 1205 if (old_fp == 0 || old_fp == (uintptr_t)-1 || old_fp == ufp) return true; 1206 1207 // stack grows downwards; if old_fp is below current fp or if the stack 1208 // frame is too large, either the stack is corrupted or fp is not saved 1209 // on stack (i.e. on x86, ebp may be used as general register). The stack 1210 // is not walkable beyond current frame. 1211 if (old_fp < ufp) return true; 1212 if (old_fp - ufp > 64 * K) return true; 1213 1214 return false; 1215 #endif 1216 } 1217 1218 1219 // Set up the boot classpath. 1220 1221 char* os::format_boot_path(const char* format_string, 1222 const char* home, 1223 int home_len, 1224 char fileSep, 1225 char pathSep) { 1226 assert((fileSep == '/' && pathSep == ':') || 1227 (fileSep == '\\' && pathSep == ';'), "unexpected separator chars"); 1228 1229 // Scan the format string to determine the length of the actual 1230 // boot classpath, and handle platform dependencies as well. 1231 int formatted_path_len = 0; 1232 const char* p; 1233 for (p = format_string; *p != 0; ++p) { 1234 if (*p == '%') formatted_path_len += home_len - 1; 1235 ++formatted_path_len; 1236 } 1237 1238 char* formatted_path = NEW_C_HEAP_ARRAY(char, formatted_path_len + 1, mtInternal); 1239 if (formatted_path == NULL) { 1240 return NULL; 1241 } 1242 1243 // Create boot classpath from format, substituting separator chars and 1244 // java home directory. 1245 char* q = formatted_path; 1246 for (p = format_string; *p != 0; ++p) { 1247 switch (*p) { 1248 case '%': 1249 strcpy(q, home); 1250 q += home_len; 1251 break; 1252 case '/': 1253 *q++ = fileSep; 1254 break; 1255 case ':': 1256 *q++ = pathSep; 1257 break; 1258 default: 1259 *q++ = *p; 1260 } 1261 } 1262 *q = '\0'; 1263 1264 assert((q - formatted_path) == formatted_path_len, "formatted_path size botched"); 1265 return formatted_path; 1266 } 1267 1268 bool os::set_boot_path(char fileSep, char pathSep) { 1269 const char* home = Arguments::get_java_home(); 1270 int home_len = (int)strlen(home); 1271 1272 struct stat st; 1273 1274 // modular image if "modules" jimage exists 1275 char* jimage = format_boot_path("%/lib/" MODULES_IMAGE_NAME, home, home_len, fileSep, pathSep); 1276 if (jimage == NULL) return false; 1277 bool has_jimage = (os::stat(jimage, &st) == 0); 1278 if (has_jimage) { 1279 Arguments::set_sysclasspath(jimage, true); 1280 FREE_C_HEAP_ARRAY(char, jimage); 1281 return true; 1282 } 1283 FREE_C_HEAP_ARRAY(char, jimage); 1284 1285 // check if developer build with exploded modules 1286 char* base_classes = format_boot_path("%/modules/" JAVA_BASE_NAME, home, home_len, fileSep, pathSep); 1287 if (base_classes == NULL) return false; 1288 if (os::stat(base_classes, &st) == 0) { 1289 Arguments::set_sysclasspath(base_classes, false); 1290 FREE_C_HEAP_ARRAY(char, base_classes); 1291 return true; 1292 } 1293 FREE_C_HEAP_ARRAY(char, base_classes); 1294 1295 return false; 1296 } 1297 1298 /* 1299 * Splits a path, based on its separator, the number of 1300 * elements is returned back in n. 1301 * It is the callers responsibility to: 1302 * a> check the value of n, and n may be 0. 1303 * b> ignore any empty path elements 1304 * c> free up the data. 1305 */ 1306 char** os::split_path(const char* path, int* n) { 1307 *n = 0; 1308 if (path == NULL || strlen(path) == 0) { 1309 return NULL; 1310 } 1311 const char psepchar = *os::path_separator(); 1312 char* inpath = (char*)NEW_C_HEAP_ARRAY(char, strlen(path) + 1, mtInternal); 1313 if (inpath == NULL) { 1314 return NULL; 1315 } 1316 strcpy(inpath, path); 1317 int count = 1; 1318 char* p = strchr(inpath, psepchar); 1319 // Get a count of elements to allocate memory 1320 while (p != NULL) { 1321 count++; 1322 p++; 1323 p = strchr(p, psepchar); 1324 } 1325 char** opath = (char**) NEW_C_HEAP_ARRAY(char*, count, mtInternal); 1326 if (opath == NULL) { 1327 return NULL; 1328 } 1329 1330 // do the actual splitting 1331 p = inpath; 1332 for (int i = 0 ; i < count ; i++) { 1333 size_t len = strcspn(p, os::path_separator()); 1334 if (len > JVM_MAXPATHLEN) { 1335 return NULL; 1336 } 1337 // allocate the string and add terminator storage 1338 char* s = (char*)NEW_C_HEAP_ARRAY(char, len + 1, mtInternal); 1339 if (s == NULL) { 1340 return NULL; 1341 } 1342 strncpy(s, p, len); 1343 s[len] = '\0'; 1344 opath[i] = s; 1345 p += len + 1; 1346 } 1347 FREE_C_HEAP_ARRAY(char, inpath); 1348 *n = count; 1349 return opath; 1350 } 1351 1352 void os::set_memory_serialize_page(address page) { 1353 int count = log2_intptr(sizeof(class JavaThread)) - log2_intptr(64); 1354 _mem_serialize_page = (volatile int32_t *)page; 1355 // We initialize the serialization page shift count here 1356 // We assume a cache line size of 64 bytes 1357 assert(SerializePageShiftCount == count, "JavaThread size changed; " 1358 "SerializePageShiftCount constant should be %d", count); 1359 set_serialize_page_mask((uintptr_t)(vm_page_size() - sizeof(int32_t))); 1360 } 1361 1362 static volatile intptr_t SerializePageLock = 0; 1363 1364 // This method is called from signal handler when SIGSEGV occurs while the current 1365 // thread tries to store to the "read-only" memory serialize page during state 1366 // transition. 1367 void os::block_on_serialize_page_trap() { 1368 log_debug(safepoint)("Block until the serialize page permission restored"); 1369 1370 // When VMThread is holding the SerializePageLock during modifying the 1371 // access permission of the memory serialize page, the following call 1372 // will block until the permission of that page is restored to rw. 1373 // Generally, it is unsafe to manipulate locks in signal handlers, but in 1374 // this case, it's OK as the signal is synchronous and we know precisely when 1375 // it can occur. 1376 Thread::muxAcquire(&SerializePageLock, "set_memory_serialize_page"); 1377 Thread::muxRelease(&SerializePageLock); 1378 } 1379 1380 // Serialize all thread state variables 1381 void os::serialize_thread_states() { 1382 // On some platforms such as Solaris & Linux, the time duration of the page 1383 // permission restoration is observed to be much longer than expected due to 1384 // scheduler starvation problem etc. To avoid the long synchronization 1385 // time and expensive page trap spinning, 'SerializePageLock' is used to block 1386 // the mutator thread if such case is encountered. See bug 6546278 for details. 1387 Thread::muxAcquire(&SerializePageLock, "serialize_thread_states"); 1388 os::protect_memory((char *)os::get_memory_serialize_page(), 1389 os::vm_page_size(), MEM_PROT_READ); 1390 os::protect_memory((char *)os::get_memory_serialize_page(), 1391 os::vm_page_size(), MEM_PROT_RW); 1392 Thread::muxRelease(&SerializePageLock); 1393 } 1394 1395 // Returns true if the current stack pointer is above the stack shadow 1396 // pages, false otherwise. 1397 bool os::stack_shadow_pages_available(Thread *thread, const methodHandle& method, address sp) { 1398 if (!thread->is_Java_thread()) return false; 1399 // Check if we have StackShadowPages above the yellow zone. This parameter 1400 // is dependent on the depth of the maximum VM call stack possible from 1401 // the handler for stack overflow. 'instanceof' in the stack overflow 1402 // handler or a println uses at least 8k stack of VM and native code 1403 // respectively. 1404 const int framesize_in_bytes = 1405 Interpreter::size_top_interpreter_activation(method()) * wordSize; 1406 1407 address limit = ((JavaThread*)thread)->stack_end() + 1408 (JavaThread::stack_guard_zone_size() + JavaThread::stack_shadow_zone_size()); 1409 1410 return sp > (limit + framesize_in_bytes); 1411 } 1412 1413 size_t os::page_size_for_region(size_t region_size, size_t min_pages, bool must_be_aligned) { 1414 assert(min_pages > 0, "sanity"); 1415 if (UseLargePages) { 1416 const size_t max_page_size = region_size / min_pages; 1417 1418 for (size_t i = 0; _page_sizes[i] != 0; ++i) { 1419 const size_t page_size = _page_sizes[i]; 1420 if (page_size <= max_page_size) { 1421 if (!must_be_aligned || is_aligned(region_size, page_size)) { 1422 return page_size; 1423 } 1424 } 1425 } 1426 } 1427 1428 return vm_page_size(); 1429 } 1430 1431 size_t os::page_size_for_region_aligned(size_t region_size, size_t min_pages) { 1432 return page_size_for_region(region_size, min_pages, true); 1433 } 1434 1435 size_t os::page_size_for_region_unaligned(size_t region_size, size_t min_pages) { 1436 return page_size_for_region(region_size, min_pages, false); 1437 } 1438 1439 static const char* errno_to_string (int e, bool short_text) { 1440 #define ALL_SHARED_ENUMS(X) \ 1441 X(E2BIG, "Argument list too long") \ 1442 X(EACCES, "Permission denied") \ 1443 X(EADDRINUSE, "Address in use") \ 1444 X(EADDRNOTAVAIL, "Address not available") \ 1445 X(EAFNOSUPPORT, "Address family not supported") \ 1446 X(EAGAIN, "Resource unavailable, try again") \ 1447 X(EALREADY, "Connection already in progress") \ 1448 X(EBADF, "Bad file descriptor") \ 1449 X(EBADMSG, "Bad message") \ 1450 X(EBUSY, "Device or resource busy") \ 1451 X(ECANCELED, "Operation canceled") \ 1452 X(ECHILD, "No child processes") \ 1453 X(ECONNABORTED, "Connection aborted") \ 1454 X(ECONNREFUSED, "Connection refused") \ 1455 X(ECONNRESET, "Connection reset") \ 1456 X(EDEADLK, "Resource deadlock would occur") \ 1457 X(EDESTADDRREQ, "Destination address required") \ 1458 X(EDOM, "Mathematics argument out of domain of function") \ 1459 X(EEXIST, "File exists") \ 1460 X(EFAULT, "Bad address") \ 1461 X(EFBIG, "File too large") \ 1462 X(EHOSTUNREACH, "Host is unreachable") \ 1463 X(EIDRM, "Identifier removed") \ 1464 X(EILSEQ, "Illegal byte sequence") \ 1465 X(EINPROGRESS, "Operation in progress") \ 1466 X(EINTR, "Interrupted function") \ 1467 X(EINVAL, "Invalid argument") \ 1468 X(EIO, "I/O error") \ 1469 X(EISCONN, "Socket is connected") \ 1470 X(EISDIR, "Is a directory") \ 1471 X(ELOOP, "Too many levels of symbolic links") \ 1472 X(EMFILE, "Too many open files") \ 1473 X(EMLINK, "Too many links") \ 1474 X(EMSGSIZE, "Message too large") \ 1475 X(ENAMETOOLONG, "Filename too long") \ 1476 X(ENETDOWN, "Network is down") \ 1477 X(ENETRESET, "Connection aborted by network") \ 1478 X(ENETUNREACH, "Network unreachable") \ 1479 X(ENFILE, "Too many files open in system") \ 1480 X(ENOBUFS, "No buffer space available") \ 1481 X(ENODATA, "No message is available on the STREAM head read queue") \ 1482 X(ENODEV, "No such device") \ 1483 X(ENOENT, "No such file or directory") \ 1484 X(ENOEXEC, "Executable file format error") \ 1485 X(ENOLCK, "No locks available") \ 1486 X(ENOLINK, "Reserved") \ 1487 X(ENOMEM, "Not enough space") \ 1488 X(ENOMSG, "No message of the desired type") \ 1489 X(ENOPROTOOPT, "Protocol not available") \ 1490 X(ENOSPC, "No space left on device") \ 1491 X(ENOSR, "No STREAM resources") \ 1492 X(ENOSTR, "Not a STREAM") \ 1493 X(ENOSYS, "Function not supported") \ 1494 X(ENOTCONN, "The socket is not connected") \ 1495 X(ENOTDIR, "Not a directory") \ 1496 X(ENOTEMPTY, "Directory not empty") \ 1497 X(ENOTSOCK, "Not a socket") \ 1498 X(ENOTSUP, "Not supported") \ 1499 X(ENOTTY, "Inappropriate I/O control operation") \ 1500 X(ENXIO, "No such device or address") \ 1501 X(EOPNOTSUPP, "Operation not supported on socket") \ 1502 X(EOVERFLOW, "Value too large to be stored in data type") \ 1503 X(EPERM, "Operation not permitted") \ 1504 X(EPIPE, "Broken pipe") \ 1505 X(EPROTO, "Protocol error") \ 1506 X(EPROTONOSUPPORT, "Protocol not supported") \ 1507 X(EPROTOTYPE, "Protocol wrong type for socket") \ 1508 X(ERANGE, "Result too large") \ 1509 X(EROFS, "Read-only file system") \ 1510 X(ESPIPE, "Invalid seek") \ 1511 X(ESRCH, "No such process") \ 1512 X(ETIME, "Stream ioctl() timeout") \ 1513 X(ETIMEDOUT, "Connection timed out") \ 1514 X(ETXTBSY, "Text file busy") \ 1515 X(EWOULDBLOCK, "Operation would block") \ 1516 X(EXDEV, "Cross-device link") 1517 1518 #define DEFINE_ENTRY(e, text) { e, #e, text }, 1519 1520 static const struct { 1521 int v; 1522 const char* short_text; 1523 const char* long_text; 1524 } table [] = { 1525 1526 ALL_SHARED_ENUMS(DEFINE_ENTRY) 1527 1528 // The following enums are not defined on all platforms. 1529 #ifdef ESTALE 1530 DEFINE_ENTRY(ESTALE, "Reserved") 1531 #endif 1532 #ifdef EDQUOT 1533 DEFINE_ENTRY(EDQUOT, "Reserved") 1534 #endif 1535 #ifdef EMULTIHOP 1536 DEFINE_ENTRY(EMULTIHOP, "Reserved") 1537 #endif 1538 1539 // End marker. 1540 { -1, "Unknown errno", "Unknown error" } 1541 1542 }; 1543 1544 #undef DEFINE_ENTRY 1545 #undef ALL_FLAGS 1546 1547 int i = 0; 1548 while (table[i].v != -1 && table[i].v != e) { 1549 i ++; 1550 } 1551 1552 return short_text ? table[i].short_text : table[i].long_text; 1553 1554 } 1555 1556 const char* os::strerror(int e) { 1557 return errno_to_string(e, false); 1558 } 1559 1560 const char* os::errno_name(int e) { 1561 return errno_to_string(e, true); 1562 } 1563 1564 void os::trace_page_sizes(const char* str, const size_t* page_sizes, int count) { 1565 LogTarget(Info, pagesize) log; 1566 if (log.is_enabled()) { 1567 LogStream out(log); 1568 1569 out.print("%s: ", str); 1570 for (int i = 0; i < count; ++i) { 1571 out.print(" " SIZE_FORMAT, page_sizes[i]); 1572 } 1573 out.cr(); 1574 } 1575 } 1576 1577 #define trace_page_size_params(size) byte_size_in_exact_unit(size), exact_unit_for_byte_size(size) 1578 1579 void os::trace_page_sizes(const char* str, 1580 const size_t region_min_size, 1581 const size_t region_max_size, 1582 const size_t page_size, 1583 const char* base, 1584 const size_t size) { 1585 1586 log_info(pagesize)("%s: " 1587 " min=" SIZE_FORMAT "%s" 1588 " max=" SIZE_FORMAT "%s" 1589 " base=" PTR_FORMAT 1590 " page_size=" SIZE_FORMAT "%s" 1591 " size=" SIZE_FORMAT "%s", 1592 str, 1593 trace_page_size_params(region_min_size), 1594 trace_page_size_params(region_max_size), 1595 p2i(base), 1596 trace_page_size_params(page_size), 1597 trace_page_size_params(size)); 1598 } 1599 1600 void os::trace_page_sizes_for_requested_size(const char* str, 1601 const size_t requested_size, 1602 const size_t page_size, 1603 const size_t alignment, 1604 const char* base, 1605 const size_t size) { 1606 1607 log_info(pagesize)("%s:" 1608 " req_size=" SIZE_FORMAT "%s" 1609 " base=" PTR_FORMAT 1610 " page_size=" SIZE_FORMAT "%s" 1611 " alignment=" SIZE_FORMAT "%s" 1612 " size=" SIZE_FORMAT "%s", 1613 str, 1614 trace_page_size_params(requested_size), 1615 p2i(base), 1616 trace_page_size_params(page_size), 1617 trace_page_size_params(alignment), 1618 trace_page_size_params(size)); 1619 } 1620 1621 1622 // This is the working definition of a server class machine: 1623 // >= 2 physical CPU's and >=2GB of memory, with some fuzz 1624 // because the graphics memory (?) sometimes masks physical memory. 1625 // If you want to change the definition of a server class machine 1626 // on some OS or platform, e.g., >=4GB on Windows platforms, 1627 // then you'll have to parameterize this method based on that state, 1628 // as was done for logical processors here, or replicate and 1629 // specialize this method for each platform. (Or fix os to have 1630 // some inheritance structure and use subclassing. Sigh.) 1631 // If you want some platform to always or never behave as a server 1632 // class machine, change the setting of AlwaysActAsServerClassMachine 1633 // and NeverActAsServerClassMachine in globals*.hpp. 1634 bool os::is_server_class_machine() { 1635 // First check for the early returns 1636 if (NeverActAsServerClassMachine) { 1637 return false; 1638 } 1639 if (AlwaysActAsServerClassMachine) { 1640 return true; 1641 } 1642 // Then actually look at the machine 1643 bool result = false; 1644 const unsigned int server_processors = 2; 1645 const julong server_memory = 2UL * G; 1646 // We seem not to get our full complement of memory. 1647 // We allow some part (1/8?) of the memory to be "missing", 1648 // based on the sizes of DIMMs, and maybe graphics cards. 1649 const julong missing_memory = 256UL * M; 1650 1651 /* Is this a server class machine? */ 1652 if ((os::active_processor_count() >= (int)server_processors) && 1653 (os::physical_memory() >= (server_memory - missing_memory))) { 1654 const unsigned int logical_processors = 1655 VM_Version::logical_processors_per_package(); 1656 if (logical_processors > 1) { 1657 const unsigned int physical_packages = 1658 os::active_processor_count() / logical_processors; 1659 if (physical_packages >= server_processors) { 1660 result = true; 1661 } 1662 } else { 1663 result = true; 1664 } 1665 } 1666 return result; 1667 } 1668 1669 void os::initialize_initial_active_processor_count() { 1670 assert(_initial_active_processor_count == 0, "Initial active processor count already set."); 1671 _initial_active_processor_count = active_processor_count(); 1672 log_debug(os)("Initial active processor count set to %d" , _initial_active_processor_count); 1673 } 1674 1675 void os::SuspendedThreadTask::run() { 1676 assert(Threads_lock->owned_by_self() || (_thread == VMThread::vm_thread()), "must have threads lock to call this"); 1677 internal_do_task(); 1678 _done = true; 1679 } 1680 1681 bool os::create_stack_guard_pages(char* addr, size_t bytes) { 1682 return os::pd_create_stack_guard_pages(addr, bytes); 1683 } 1684 1685 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint) { 1686 char* result = pd_reserve_memory(bytes, addr, alignment_hint); 1687 if (result != NULL) { 1688 MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC); 1689 } 1690 1691 return result; 1692 } 1693 1694 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint, 1695 MEMFLAGS flags) { 1696 char* result = pd_reserve_memory(bytes, addr, alignment_hint); 1697 if (result != NULL) { 1698 MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC); 1699 MemTracker::record_virtual_memory_type((address)result, flags); 1700 } 1701 1702 return result; 1703 } 1704 1705 char* os::attempt_reserve_memory_at(size_t bytes, char* addr) { 1706 char* result = pd_attempt_reserve_memory_at(bytes, addr); 1707 if (result != NULL) { 1708 MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC); 1709 } 1710 return result; 1711 } 1712 1713 void os::split_reserved_memory(char *base, size_t size, 1714 size_t split, bool realloc) { 1715 pd_split_reserved_memory(base, size, split, realloc); 1716 } 1717 1718 bool os::commit_memory(char* addr, size_t bytes, bool executable) { 1719 bool res = pd_commit_memory(addr, bytes, executable); 1720 if (res) { 1721 MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC); 1722 } 1723 return res; 1724 } 1725 1726 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint, 1727 bool executable) { 1728 bool res = os::pd_commit_memory(addr, size, alignment_hint, executable); 1729 if (res) { 1730 MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC); 1731 } 1732 return res; 1733 } 1734 1735 void os::commit_memory_or_exit(char* addr, size_t bytes, bool executable, 1736 const char* mesg) { 1737 pd_commit_memory_or_exit(addr, bytes, executable, mesg); 1738 MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC); 1739 } 1740 1741 void os::commit_memory_or_exit(char* addr, size_t size, size_t alignment_hint, 1742 bool executable, const char* mesg) { 1743 os::pd_commit_memory_or_exit(addr, size, alignment_hint, executable, mesg); 1744 MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC); 1745 } 1746 1747 bool os::uncommit_memory(char* addr, size_t bytes) { 1748 bool res; 1749 if (MemTracker::tracking_level() > NMT_minimal) { 1750 Tracker tkr = MemTracker::get_virtual_memory_uncommit_tracker(); 1751 res = pd_uncommit_memory(addr, bytes); 1752 if (res) { 1753 tkr.record((address)addr, bytes); 1754 } 1755 } else { 1756 res = pd_uncommit_memory(addr, bytes); 1757 } 1758 return res; 1759 } 1760 1761 bool os::release_memory(char* addr, size_t bytes) { 1762 bool res; 1763 if (MemTracker::tracking_level() > NMT_minimal) { 1764 Tracker tkr = MemTracker::get_virtual_memory_release_tracker(); 1765 res = pd_release_memory(addr, bytes); 1766 if (res) { 1767 tkr.record((address)addr, bytes); 1768 } 1769 } else { 1770 res = pd_release_memory(addr, bytes); 1771 } 1772 return res; 1773 } 1774 1775 void os::pretouch_memory(void* start, void* end, size_t page_size) { 1776 for (volatile char *p = (char*)start; p < (char*)end; p += page_size) { 1777 *p = 0; 1778 } 1779 } 1780 1781 char* os::map_memory(int fd, const char* file_name, size_t file_offset, 1782 char *addr, size_t bytes, bool read_only, 1783 bool allow_exec) { 1784 char* result = pd_map_memory(fd, file_name, file_offset, addr, bytes, read_only, allow_exec); 1785 if (result != NULL) { 1786 MemTracker::record_virtual_memory_reserve_and_commit((address)result, bytes, CALLER_PC); 1787 } 1788 return result; 1789 } 1790 1791 char* os::remap_memory(int fd, const char* file_name, size_t file_offset, 1792 char *addr, size_t bytes, bool read_only, 1793 bool allow_exec) { 1794 return pd_remap_memory(fd, file_name, file_offset, addr, bytes, 1795 read_only, allow_exec); 1796 } 1797 1798 bool os::unmap_memory(char *addr, size_t bytes) { 1799 bool result; 1800 if (MemTracker::tracking_level() > NMT_minimal) { 1801 Tracker tkr = MemTracker::get_virtual_memory_release_tracker(); 1802 result = pd_unmap_memory(addr, bytes); 1803 if (result) { 1804 tkr.record((address)addr, bytes); 1805 } 1806 } else { 1807 result = pd_unmap_memory(addr, bytes); 1808 } 1809 return result; 1810 } 1811 1812 void os::free_memory(char *addr, size_t bytes, size_t alignment_hint) { 1813 pd_free_memory(addr, bytes, alignment_hint); 1814 } 1815 1816 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 1817 pd_realign_memory(addr, bytes, alignment_hint); 1818 } 1819 1820 #ifndef _WINDOWS 1821 /* try to switch state from state "from" to state "to" 1822 * returns the state set after the method is complete 1823 */ 1824 os::SuspendResume::State os::SuspendResume::switch_state(os::SuspendResume::State from, 1825 os::SuspendResume::State to) 1826 { 1827 os::SuspendResume::State result = 1828 (os::SuspendResume::State) Atomic::cmpxchg((jint) to, (jint *) &_state, (jint) from); 1829 if (result == from) { 1830 // success 1831 return to; 1832 } 1833 return result; 1834 } 1835 #endif