1 /* 2 * Copyright (c) 1997, 2018, 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 "logging/log.hpp" 37 #include "interpreter/interpreter.hpp" 38 #include "logging/log.hpp" 39 #include "logging/logStream.hpp" 40 #include "memory/allocation.inline.hpp" 41 #ifdef ASSERT 42 #include "memory/guardedMemory.hpp" 43 #endif 44 #include "memory/resourceArea.hpp" 45 #include "oops/oop.inline.hpp" 46 #include "prims/jvm_misc.hpp" 47 #include "runtime/arguments.hpp" 48 #include "runtime/atomic.hpp" 49 #include "runtime/frame.inline.hpp" 50 #include "runtime/interfaceSupport.inline.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/sharedRuntime.hpp" 56 #include "runtime/stubRoutines.hpp" 57 #include "runtime/thread.inline.hpp" 58 #include "runtime/threadSMR.hpp" 59 #include "runtime/vm_version.hpp" 60 #include "services/attachListener.hpp" 61 #include "services/mallocTracker.hpp" 62 #include "services/memTracker.hpp" 63 #include "services/nmtCommon.hpp" 64 #include "services/threadService.hpp" 65 #include "utilities/align.hpp" 66 #include "utilities/defaultStream.hpp" 67 #include "utilities/events.hpp" 68 69 # include <signal.h> 70 # include <errno.h> 71 72 OSThread* os::_starting_thread = NULL; 73 address os::_polling_page = NULL; 74 volatile int32_t* os::_mem_serialize_page = NULL; 75 uintptr_t os::_serialize_page_mask = 0; 76 volatile unsigned int os::_rand_seed = 1; 77 int os::_processor_count = 0; 78 int os::_initial_active_processor_count = 0; 79 size_t os::_page_sizes[os::page_sizes_max]; 80 81 #ifndef PRODUCT 82 julong os::num_mallocs = 0; // # of calls to malloc/realloc 83 julong os::alloc_bytes = 0; // # of bytes allocated 84 julong os::num_frees = 0; // # of calls to free 85 julong os::free_bytes = 0; // # of bytes freed 86 #endif 87 88 static size_t cur_malloc_words = 0; // current size for MallocMaxTestWords 89 90 void os_init_globals() { 91 // Called from init_globals(). 92 // See Threads::create_vm() in thread.cpp, and init.cpp. 93 os::init_globals(); 94 } 95 96 static time_t get_timezone(const struct tm* time_struct) { 97 #if defined(_ALLBSD_SOURCE) 98 return time_struct->tm_gmtoff; 99 #elif defined(_WINDOWS) 100 long zone; 101 _get_timezone(&zone); 102 return static_cast<time_t>(zone); 103 #else 104 return timezone; 105 #endif 106 } 107 108 int os::snprintf(char* buf, size_t len, const char* fmt, ...) { 109 va_list args; 110 va_start(args, fmt); 111 int result = os::vsnprintf(buf, len, fmt, args); 112 va_end(args); 113 return result; 114 } 115 116 // Fill in buffer with current local time as an ISO-8601 string. 117 // E.g., yyyy-mm-ddThh:mm:ss-zzzz. 118 // Returns buffer, or NULL if it failed. 119 // This would mostly be a call to 120 // strftime(...., "%Y-%m-%d" "T" "%H:%M:%S" "%z", ....) 121 // except that on Windows the %z behaves badly, so we do it ourselves. 122 // Also, people wanted milliseconds on there, 123 // and strftime doesn't do milliseconds. 124 char* os::iso8601_time(char* buffer, size_t buffer_length, bool utc) { 125 // Output will be of the form "YYYY-MM-DDThh:mm:ss.mmm+zzzz\0" 126 // 1 2 127 // 12345678901234567890123456789 128 // format string: "%04d-%02d-%02dT%02d:%02d:%02d.%03d%c%02d%02d" 129 static const size_t needed_buffer = 29; 130 131 // Sanity check the arguments 132 if (buffer == NULL) { 133 assert(false, "NULL buffer"); 134 return NULL; 135 } 136 if (buffer_length < needed_buffer) { 137 assert(false, "buffer_length too small"); 138 return NULL; 139 } 140 // Get the current time 141 jlong milliseconds_since_19700101 = javaTimeMillis(); 142 const int milliseconds_per_microsecond = 1000; 143 const time_t seconds_since_19700101 = 144 milliseconds_since_19700101 / milliseconds_per_microsecond; 145 const int milliseconds_after_second = 146 milliseconds_since_19700101 % milliseconds_per_microsecond; 147 // Convert the time value to a tm and timezone variable 148 struct tm time_struct; 149 if (utc) { 150 if (gmtime_pd(&seconds_since_19700101, &time_struct) == NULL) { 151 assert(false, "Failed gmtime_pd"); 152 return NULL; 153 } 154 } else { 155 if (localtime_pd(&seconds_since_19700101, &time_struct) == NULL) { 156 assert(false, "Failed localtime_pd"); 157 return NULL; 158 } 159 } 160 const time_t zone = get_timezone(&time_struct); 161 162 // If daylight savings time is in effect, 163 // we are 1 hour East of our time zone 164 const time_t seconds_per_minute = 60; 165 const time_t minutes_per_hour = 60; 166 const time_t seconds_per_hour = seconds_per_minute * minutes_per_hour; 167 time_t UTC_to_local = zone; 168 if (time_struct.tm_isdst > 0) { 169 UTC_to_local = UTC_to_local - seconds_per_hour; 170 } 171 172 // No offset when dealing with UTC 173 if (utc) { 174 UTC_to_local = 0; 175 } 176 177 // Compute the time zone offset. 178 // localtime_pd() sets timezone to the difference (in seconds) 179 // between UTC and and local time. 180 // ISO 8601 says we need the difference between local time and UTC, 181 // we change the sign of the localtime_pd() result. 182 const time_t local_to_UTC = -(UTC_to_local); 183 // Then we have to figure out if if we are ahead (+) or behind (-) UTC. 184 char sign_local_to_UTC = '+'; 185 time_t abs_local_to_UTC = local_to_UTC; 186 if (local_to_UTC < 0) { 187 sign_local_to_UTC = '-'; 188 abs_local_to_UTC = -(abs_local_to_UTC); 189 } 190 // Convert time zone offset seconds to hours and minutes. 191 const time_t zone_hours = (abs_local_to_UTC / seconds_per_hour); 192 const time_t zone_min = 193 ((abs_local_to_UTC % seconds_per_hour) / seconds_per_minute); 194 195 // Print an ISO 8601 date and time stamp into the buffer 196 const int year = 1900 + time_struct.tm_year; 197 const int month = 1 + time_struct.tm_mon; 198 const int printed = jio_snprintf(buffer, buffer_length, 199 "%04d-%02d-%02dT%02d:%02d:%02d.%03d%c%02d%02d", 200 year, 201 month, 202 time_struct.tm_mday, 203 time_struct.tm_hour, 204 time_struct.tm_min, 205 time_struct.tm_sec, 206 milliseconds_after_second, 207 sign_local_to_UTC, 208 zone_hours, 209 zone_min); 210 if (printed == 0) { 211 assert(false, "Failed jio_printf"); 212 return NULL; 213 } 214 return buffer; 215 } 216 217 OSReturn os::set_priority(Thread* thread, ThreadPriority p) { 218 debug_only(Thread::check_for_dangling_thread_pointer(thread);) 219 220 if (p >= MinPriority && p <= MaxPriority) { 221 int priority = java_to_os_priority[p]; 222 return set_native_priority(thread, priority); 223 } else { 224 assert(false, "Should not happen"); 225 return OS_ERR; 226 } 227 } 228 229 // The mapping from OS priority back to Java priority may be inexact because 230 // Java priorities can map M:1 with native priorities. If you want the definite 231 // Java priority then use JavaThread::java_priority() 232 OSReturn os::get_priority(const Thread* const thread, ThreadPriority& priority) { 233 int p; 234 int os_prio; 235 OSReturn ret = get_native_priority(thread, &os_prio); 236 if (ret != OS_OK) return ret; 237 238 if (java_to_os_priority[MaxPriority] > java_to_os_priority[MinPriority]) { 239 for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] > os_prio; p--) ; 240 } else { 241 // niceness values are in reverse order 242 for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] < os_prio; p--) ; 243 } 244 priority = (ThreadPriority)p; 245 return OS_OK; 246 } 247 248 bool os::dll_build_name(char* buffer, size_t size, const char* fname) { 249 int n = jio_snprintf(buffer, size, "%s%s%s", JNI_LIB_PREFIX, fname, JNI_LIB_SUFFIX); 250 return (n != -1); 251 } 252 253 #if !defined(LINUX) && !defined(_WINDOWS) 254 bool os::committed_in_range(address start, size_t size, address& committed_start, size_t& committed_size) { 255 committed_start = start; 256 committed_size = size; 257 return true; 258 } 259 #endif 260 261 // Helper for dll_locate_lib. 262 // Pass buffer and printbuffer as we already printed the path to buffer 263 // when we called get_current_directory. This way we avoid another buffer 264 // of size MAX_PATH. 265 static bool conc_path_file_and_check(char *buffer, char *printbuffer, size_t printbuflen, 266 const char* pname, char lastchar, const char* fname) { 267 268 // Concatenate path and file name, but don't print double path separators. 269 const char *filesep = (WINDOWS_ONLY(lastchar == ':' ||) lastchar == os::file_separator()[0]) ? 270 "" : os::file_separator(); 271 int ret = jio_snprintf(printbuffer, printbuflen, "%s%s%s", pname, filesep, fname); 272 // Check whether file exists. 273 if (ret != -1) { 274 struct stat statbuf; 275 return os::stat(buffer, &statbuf) == 0; 276 } 277 return false; 278 } 279 280 bool os::dll_locate_lib(char *buffer, size_t buflen, 281 const char* pname, const char* fname) { 282 bool retval = false; 283 284 size_t fullfnamelen = strlen(JNI_LIB_PREFIX) + strlen(fname) + strlen(JNI_LIB_SUFFIX); 285 char* fullfname = (char*)NEW_C_HEAP_ARRAY(char, fullfnamelen + 1, mtInternal); 286 if (dll_build_name(fullfname, fullfnamelen + 1, fname)) { 287 const size_t pnamelen = pname ? strlen(pname) : 0; 288 289 if (pnamelen == 0) { 290 // If no path given, use current working directory. 291 const char* p = get_current_directory(buffer, buflen); 292 if (p != NULL) { 293 const size_t plen = strlen(buffer); 294 const char lastchar = buffer[plen - 1]; 295 retval = conc_path_file_and_check(buffer, &buffer[plen], buflen - plen, 296 "", lastchar, fullfname); 297 } 298 } else if (strchr(pname, *os::path_separator()) != NULL) { 299 // A list of paths. Search for the path that contains the library. 300 int n; 301 char** pelements = split_path(pname, &n); 302 if (pelements != NULL) { 303 for (int i = 0; i < n; i++) { 304 char* path = pelements[i]; 305 // Really shouldn't be NULL, but check can't hurt. 306 size_t plen = (path == NULL) ? 0 : strlen(path); 307 if (plen == 0) { 308 continue; // Skip the empty path values. 309 } 310 const char lastchar = path[plen - 1]; 311 retval = conc_path_file_and_check(buffer, buffer, buflen, path, lastchar, fullfname); 312 if (retval) break; 313 } 314 // Release the storage allocated by split_path. 315 for (int i = 0; i < n; i++) { 316 if (pelements[i] != NULL) { 317 FREE_C_HEAP_ARRAY(char, pelements[i]); 318 } 319 } 320 FREE_C_HEAP_ARRAY(char*, pelements); 321 } 322 } else { 323 // A definite path. 324 const char lastchar = pname[pnamelen-1]; 325 retval = conc_path_file_and_check(buffer, buffer, buflen, pname, lastchar, fullfname); 326 } 327 } 328 329 FREE_C_HEAP_ARRAY(char*, fullfname); 330 return retval; 331 } 332 333 // --------------------- sun.misc.Signal (optional) --------------------- 334 335 336 // SIGBREAK is sent by the keyboard to query the VM state 337 #ifndef SIGBREAK 338 #define SIGBREAK SIGQUIT 339 #endif 340 341 // sigexitnum_pd is a platform-specific special signal used for terminating the Signal thread. 342 343 344 static void signal_thread_entry(JavaThread* thread, TRAPS) { 345 os::set_priority(thread, NearMaxPriority); 346 while (true) { 347 int sig; 348 { 349 // FIXME : Currently we have not decided what should be the status 350 // for this java thread blocked here. Once we decide about 351 // that we should fix this. 352 sig = os::signal_wait(); 353 } 354 if (sig == os::sigexitnum_pd()) { 355 // Terminate the signal thread 356 return; 357 } 358 359 switch (sig) { 360 case SIGBREAK: { 361 // Check if the signal is a trigger to start the Attach Listener - in that 362 // case don't print stack traces. 363 if (!DisableAttachMechanism && AttachListener::is_init_trigger()) { 364 continue; 365 } 366 // Print stack traces 367 // Any SIGBREAK operations added here should make sure to flush 368 // the output stream (e.g. tty->flush()) after output. See 4803766. 369 // Each module also prints an extra carriage return after its output. 370 VM_PrintThreads op; 371 VMThread::execute(&op); 372 VM_PrintJNI jni_op; 373 VMThread::execute(&jni_op); 374 VM_FindDeadlocks op1(tty); 375 VMThread::execute(&op1); 376 Universe::print_heap_at_SIGBREAK(); 377 if (PrintClassHistogram) { 378 VM_GC_HeapInspection op1(tty, true /* force full GC before heap inspection */); 379 VMThread::execute(&op1); 380 } 381 if (JvmtiExport::should_post_data_dump()) { 382 JvmtiExport::post_data_dump(); 383 } 384 break; 385 } 386 default: { 387 // Dispatch the signal to java 388 HandleMark hm(THREAD); 389 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_misc_Signal(), THREAD); 390 if (klass != NULL) { 391 JavaValue result(T_VOID); 392 JavaCallArguments args; 393 args.push_int(sig); 394 JavaCalls::call_static( 395 &result, 396 klass, 397 vmSymbols::dispatch_name(), 398 vmSymbols::int_void_signature(), 399 &args, 400 THREAD 401 ); 402 } 403 if (HAS_PENDING_EXCEPTION) { 404 // tty is initialized early so we don't expect it to be null, but 405 // if it is we can't risk doing an initialization that might 406 // trigger additional out-of-memory conditions 407 if (tty != NULL) { 408 char klass_name[256]; 409 char tmp_sig_name[16]; 410 const char* sig_name = "UNKNOWN"; 411 InstanceKlass::cast(PENDING_EXCEPTION->klass())-> 412 name()->as_klass_external_name(klass_name, 256); 413 if (os::exception_name(sig, tmp_sig_name, 16) != NULL) 414 sig_name = tmp_sig_name; 415 warning("Exception %s occurred dispatching signal %s to handler" 416 "- the VM may need to be forcibly terminated", 417 klass_name, sig_name ); 418 } 419 CLEAR_PENDING_EXCEPTION; 420 } 421 } 422 } 423 } 424 } 425 426 void os::init_before_ergo() { 427 initialize_initial_active_processor_count(); 428 // We need to initialize large page support here because ergonomics takes some 429 // decisions depending on large page support and the calculated large page size. 430 large_page_init(); 431 432 // We need to adapt the configured number of stack protection pages given 433 // in 4K pages to the actual os page size. We must do this before setting 434 // up minimal stack sizes etc. in os::init_2(). 435 JavaThread::set_stack_red_zone_size (align_up(StackRedPages * 4 * K, vm_page_size())); 436 JavaThread::set_stack_yellow_zone_size (align_up(StackYellowPages * 4 * K, vm_page_size())); 437 JavaThread::set_stack_reserved_zone_size(align_up(StackReservedPages * 4 * K, vm_page_size())); 438 JavaThread::set_stack_shadow_zone_size (align_up(StackShadowPages * 4 * K, vm_page_size())); 439 440 // VM version initialization identifies some characteristics of the 441 // platform that are used during ergonomic decisions. 442 VM_Version::init_before_ergo(); 443 } 444 445 void os::initialize_jdk_signal_support(TRAPS) { 446 if (!ReduceSignalUsage) { 447 // Setup JavaThread for processing signals 448 const char thread_name[] = "Signal Dispatcher"; 449 Handle string = java_lang_String::create_from_str(thread_name, CHECK); 450 451 // Initialize thread_oop to put it into the system threadGroup 452 Handle thread_group (THREAD, Universe::system_thread_group()); 453 Handle thread_oop = JavaCalls::construct_new_instance(SystemDictionary::Thread_klass(), 454 vmSymbols::threadgroup_string_void_signature(), 455 thread_group, 456 string, 457 CHECK); 458 459 Klass* group = SystemDictionary::ThreadGroup_klass(); 460 JavaValue result(T_VOID); 461 JavaCalls::call_special(&result, 462 thread_group, 463 group, 464 vmSymbols::add_method_name(), 465 vmSymbols::thread_void_signature(), 466 thread_oop, 467 CHECK); 468 469 { MutexLocker mu(Threads_lock); 470 JavaThread* signal_thread = new JavaThread(&signal_thread_entry); 471 472 // At this point it may be possible that no osthread was created for the 473 // JavaThread due to lack of memory. We would have to throw an exception 474 // in that case. However, since this must work and we do not allow 475 // exceptions anyway, check and abort if this fails. 476 if (signal_thread == NULL || signal_thread->osthread() == NULL) { 477 vm_exit_during_initialization("java.lang.OutOfMemoryError", 478 os::native_thread_creation_failed_msg()); 479 } 480 481 java_lang_Thread::set_thread(thread_oop(), signal_thread); 482 java_lang_Thread::set_priority(thread_oop(), NearMaxPriority); 483 java_lang_Thread::set_daemon(thread_oop()); 484 485 signal_thread->set_threadObj(thread_oop()); 486 Threads::add(signal_thread); 487 Thread::start(signal_thread); 488 } 489 // Handle ^BREAK 490 os::signal(SIGBREAK, os::user_handler()); 491 } 492 } 493 494 495 void os::terminate_signal_thread() { 496 if (!ReduceSignalUsage) 497 signal_notify(sigexitnum_pd()); 498 } 499 500 501 // --------------------- loading libraries --------------------- 502 503 typedef jint (JNICALL *JNI_OnLoad_t)(JavaVM *, void *); 504 extern struct JavaVM_ main_vm; 505 506 static void* _native_java_library = NULL; 507 508 void* os::native_java_library() { 509 if (_native_java_library == NULL) { 510 char buffer[JVM_MAXPATHLEN]; 511 char ebuf[1024]; 512 513 // Try to load verify dll first. In 1.3 java dll depends on it and is not 514 // always able to find it when the loading executable is outside the JDK. 515 // In order to keep working with 1.2 we ignore any loading errors. 516 if (dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(), 517 "verify")) { 518 dll_load(buffer, ebuf, sizeof(ebuf)); 519 } 520 521 // Load java dll 522 if (dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(), 523 "java")) { 524 _native_java_library = dll_load(buffer, ebuf, sizeof(ebuf)); 525 } 526 if (_native_java_library == NULL) { 527 vm_exit_during_initialization("Unable to load native library", ebuf); 528 } 529 530 #if defined(__OpenBSD__) 531 // Work-around OpenBSD's lack of $ORIGIN support by pre-loading libnet.so 532 // ignore errors 533 if (dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(), 534 "net")) { 535 dll_load(buffer, ebuf, sizeof(ebuf)); 536 } 537 #endif 538 } 539 return _native_java_library; 540 } 541 542 /* 543 * Support for finding Agent_On(Un)Load/Attach<_lib_name> if it exists. 544 * If check_lib == true then we are looking for an 545 * Agent_OnLoad_lib_name or Agent_OnAttach_lib_name function to determine if 546 * this library is statically linked into the image. 547 * If check_lib == false then we will look for the appropriate symbol in the 548 * executable if agent_lib->is_static_lib() == true or in the shared library 549 * referenced by 'handle'. 550 */ 551 void* os::find_agent_function(AgentLibrary *agent_lib, bool check_lib, 552 const char *syms[], size_t syms_len) { 553 assert(agent_lib != NULL, "sanity check"); 554 const char *lib_name; 555 void *handle = agent_lib->os_lib(); 556 void *entryName = NULL; 557 char *agent_function_name; 558 size_t i; 559 560 // If checking then use the agent name otherwise test is_static_lib() to 561 // see how to process this lookup 562 lib_name = ((check_lib || agent_lib->is_static_lib()) ? agent_lib->name() : NULL); 563 for (i = 0; i < syms_len; i++) { 564 agent_function_name = build_agent_function_name(syms[i], lib_name, agent_lib->is_absolute_path()); 565 if (agent_function_name == NULL) { 566 break; 567 } 568 entryName = dll_lookup(handle, agent_function_name); 569 FREE_C_HEAP_ARRAY(char, agent_function_name); 570 if (entryName != NULL) { 571 break; 572 } 573 } 574 return entryName; 575 } 576 577 // See if the passed in agent is statically linked into the VM image. 578 bool os::find_builtin_agent(AgentLibrary *agent_lib, const char *syms[], 579 size_t syms_len) { 580 void *ret; 581 void *proc_handle; 582 void *save_handle; 583 584 assert(agent_lib != NULL, "sanity check"); 585 if (agent_lib->name() == NULL) { 586 return false; 587 } 588 proc_handle = get_default_process_handle(); 589 // Check for Agent_OnLoad/Attach_lib_name function 590 save_handle = agent_lib->os_lib(); 591 // We want to look in this process' symbol table. 592 agent_lib->set_os_lib(proc_handle); 593 ret = find_agent_function(agent_lib, true, syms, syms_len); 594 if (ret != NULL) { 595 // Found an entry point like Agent_OnLoad_lib_name so we have a static agent 596 agent_lib->set_valid(); 597 agent_lib->set_static_lib(true); 598 return true; 599 } 600 agent_lib->set_os_lib(save_handle); 601 return false; 602 } 603 604 // --------------------- heap allocation utilities --------------------- 605 606 char *os::strdup(const char *str, MEMFLAGS flags) { 607 size_t size = strlen(str); 608 char *dup_str = (char *)malloc(size + 1, flags); 609 if (dup_str == NULL) return NULL; 610 strcpy(dup_str, str); 611 return dup_str; 612 } 613 614 char* os::strdup_check_oom(const char* str, MEMFLAGS flags) { 615 char* p = os::strdup(str, flags); 616 if (p == NULL) { 617 vm_exit_out_of_memory(strlen(str) + 1, OOM_MALLOC_ERROR, "os::strdup_check_oom"); 618 } 619 return p; 620 } 621 622 623 #define paranoid 0 /* only set to 1 if you suspect checking code has bug */ 624 625 #ifdef ASSERT 626 627 static void verify_memory(void* ptr) { 628 GuardedMemory guarded(ptr); 629 if (!guarded.verify_guards()) { 630 LogTarget(Warning, malloc, free) lt; 631 ResourceMark rm; 632 LogStream ls(lt); 633 ls.print_cr("## nof_mallocs = " UINT64_FORMAT ", nof_frees = " UINT64_FORMAT, os::num_mallocs, os::num_frees); 634 ls.print_cr("## memory stomp:"); 635 guarded.print_on(&ls); 636 fatal("memory stomping error"); 637 } 638 } 639 640 #endif 641 642 // 643 // This function supports testing of the malloc out of memory 644 // condition without really running the system out of memory. 645 // 646 static bool has_reached_max_malloc_test_peak(size_t alloc_size) { 647 if (MallocMaxTestWords > 0) { 648 size_t words = (alloc_size / BytesPerWord); 649 650 if ((cur_malloc_words + words) > MallocMaxTestWords) { 651 return true; 652 } 653 Atomic::add(words, &cur_malloc_words); 654 } 655 return false; 656 } 657 658 void* os::malloc(size_t size, MEMFLAGS flags) { 659 return os::malloc(size, flags, CALLER_PC); 660 } 661 662 void* os::malloc(size_t size, MEMFLAGS memflags, const NativeCallStack& stack) { 663 NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1)); 664 NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size)); 665 666 // Since os::malloc can be called when the libjvm.{dll,so} is 667 // first loaded and we don't have a thread yet we must accept NULL also here. 668 assert(!os::ThreadCrashProtection::is_crash_protected(Thread::current_or_null()), 669 "malloc() not allowed when crash protection is set"); 670 671 if (size == 0) { 672 // return a valid pointer if size is zero 673 // if NULL is returned the calling functions assume out of memory. 674 size = 1; 675 } 676 677 // NMT support 678 NMT_TrackingLevel level = MemTracker::tracking_level(); 679 size_t nmt_header_size = MemTracker::malloc_header_size(level); 680 681 #ifndef ASSERT 682 const size_t alloc_size = size + nmt_header_size; 683 #else 684 const size_t alloc_size = GuardedMemory::get_total_size(size + nmt_header_size); 685 if (size + nmt_header_size > alloc_size) { // Check for rollover. 686 return NULL; 687 } 688 #endif 689 690 // For the test flag -XX:MallocMaxTestWords 691 if (has_reached_max_malloc_test_peak(size)) { 692 return NULL; 693 } 694 695 u_char* ptr; 696 ptr = (u_char*)::malloc(alloc_size); 697 698 #ifdef ASSERT 699 if (ptr == NULL) { 700 return NULL; 701 } 702 // Wrap memory with guard 703 GuardedMemory guarded(ptr, size + nmt_header_size); 704 ptr = guarded.get_user_ptr(); 705 #endif 706 if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) { 707 log_warning(malloc, free)("os::malloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, p2i(ptr)); 708 breakpoint(); 709 } 710 debug_only(if (paranoid) verify_memory(ptr)); 711 712 // we do not track guard memory 713 return MemTracker::record_malloc((address)ptr, size, memflags, stack, level); 714 } 715 716 void* os::realloc(void *memblock, size_t size, MEMFLAGS flags) { 717 return os::realloc(memblock, size, flags, CALLER_PC); 718 } 719 720 void* os::realloc(void *memblock, size_t size, MEMFLAGS memflags, const NativeCallStack& stack) { 721 722 // For the test flag -XX:MallocMaxTestWords 723 if (has_reached_max_malloc_test_peak(size)) { 724 return NULL; 725 } 726 727 if (size == 0) { 728 // return a valid pointer if size is zero 729 // if NULL is returned the calling functions assume out of memory. 730 size = 1; 731 } 732 733 #ifndef ASSERT 734 NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1)); 735 NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size)); 736 // NMT support 737 void* membase = MemTracker::record_free(memblock); 738 NMT_TrackingLevel level = MemTracker::tracking_level(); 739 size_t nmt_header_size = MemTracker::malloc_header_size(level); 740 void* ptr = ::realloc(membase, size + nmt_header_size); 741 return MemTracker::record_malloc(ptr, size, memflags, stack, level); 742 #else 743 if (memblock == NULL) { 744 return os::malloc(size, memflags, stack); 745 } 746 if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) { 747 log_warning(malloc, free)("os::realloc caught " PTR_FORMAT, p2i(memblock)); 748 breakpoint(); 749 } 750 // NMT support 751 void* membase = MemTracker::malloc_base(memblock); 752 verify_memory(membase); 753 // always move the block 754 void* ptr = os::malloc(size, memflags, stack); 755 // Copy to new memory if malloc didn't fail 756 if (ptr != NULL ) { 757 GuardedMemory guarded(MemTracker::malloc_base(memblock)); 758 // Guard's user data contains NMT header 759 size_t memblock_size = guarded.get_user_size() - MemTracker::malloc_header_size(memblock); 760 memcpy(ptr, memblock, MIN2(size, memblock_size)); 761 if (paranoid) verify_memory(MemTracker::malloc_base(ptr)); 762 if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) { 763 log_warning(malloc, free)("os::realloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, p2i(ptr)); 764 breakpoint(); 765 } 766 os::free(memblock); 767 } 768 return ptr; 769 #endif 770 } 771 772 773 void os::free(void *memblock) { 774 NOT_PRODUCT(inc_stat_counter(&num_frees, 1)); 775 #ifdef ASSERT 776 if (memblock == NULL) return; 777 if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) { 778 log_warning(malloc, free)("os::free caught " PTR_FORMAT, p2i(memblock)); 779 breakpoint(); 780 } 781 void* membase = MemTracker::record_free(memblock); 782 verify_memory(membase); 783 784 GuardedMemory guarded(membase); 785 size_t size = guarded.get_user_size(); 786 inc_stat_counter(&free_bytes, size); 787 membase = guarded.release_for_freeing(); 788 ::free(membase); 789 #else 790 void* membase = MemTracker::record_free(memblock); 791 ::free(membase); 792 #endif 793 } 794 795 void os::init_random(unsigned int initval) { 796 _rand_seed = initval; 797 } 798 799 800 static int random_helper(unsigned int rand_seed) { 801 /* standard, well-known linear congruential random generator with 802 * next_rand = (16807*seed) mod (2**31-1) 803 * see 804 * (1) "Random Number Generators: Good Ones Are Hard to Find", 805 * S.K. Park and K.W. Miller, Communications of the ACM 31:10 (Oct 1988), 806 * (2) "Two Fast Implementations of the 'Minimal Standard' Random 807 * Number Generator", David G. Carta, Comm. ACM 33, 1 (Jan 1990), pp. 87-88. 808 */ 809 const unsigned int a = 16807; 810 const unsigned int m = 2147483647; 811 const int q = m / a; assert(q == 127773, "weird math"); 812 const int r = m % a; assert(r == 2836, "weird math"); 813 814 // compute az=2^31p+q 815 unsigned int lo = a * (rand_seed & 0xFFFF); 816 unsigned int hi = a * (rand_seed >> 16); 817 lo += (hi & 0x7FFF) << 16; 818 819 // if q overflowed, ignore the overflow and increment q 820 if (lo > m) { 821 lo &= m; 822 ++lo; 823 } 824 lo += hi >> 15; 825 826 // if (p+q) overflowed, ignore the overflow and increment (p+q) 827 if (lo > m) { 828 lo &= m; 829 ++lo; 830 } 831 return lo; 832 } 833 834 int os::random() { 835 // Make updating the random seed thread safe. 836 while (true) { 837 unsigned int seed = _rand_seed; 838 unsigned int rand = random_helper(seed); 839 if (Atomic::cmpxchg(rand, &_rand_seed, seed) == seed) { 840 return static_cast<int>(rand); 841 } 842 } 843 } 844 845 // The INITIALIZED state is distinguished from the SUSPENDED state because the 846 // conditions in which a thread is first started are different from those in which 847 // a suspension is resumed. These differences make it hard for us to apply the 848 // tougher checks when starting threads that we want to do when resuming them. 849 // However, when start_thread is called as a result of Thread.start, on a Java 850 // thread, the operation is synchronized on the Java Thread object. So there 851 // cannot be a race to start the thread and hence for the thread to exit while 852 // we are working on it. Non-Java threads that start Java threads either have 853 // to do so in a context in which races are impossible, or should do appropriate 854 // locking. 855 856 void os::start_thread(Thread* thread) { 857 // guard suspend/resume 858 MutexLockerEx ml(thread->SR_lock(), Mutex::_no_safepoint_check_flag); 859 OSThread* osthread = thread->osthread(); 860 osthread->set_state(RUNNABLE); 861 pd_start_thread(thread); 862 } 863 864 void os::abort(bool dump_core) { 865 abort(dump_core && CreateCoredumpOnCrash, NULL, NULL); 866 } 867 868 //--------------------------------------------------------------------------- 869 // Helper functions for fatal error handler 870 871 void os::print_hex_dump(outputStream* st, address start, address end, int unitsize) { 872 assert(unitsize == 1 || unitsize == 2 || unitsize == 4 || unitsize == 8, "just checking"); 873 874 int cols = 0; 875 int cols_per_line = 0; 876 switch (unitsize) { 877 case 1: cols_per_line = 16; break; 878 case 2: cols_per_line = 8; break; 879 case 4: cols_per_line = 4; break; 880 case 8: cols_per_line = 2; break; 881 default: return; 882 } 883 884 address p = start; 885 st->print(PTR_FORMAT ": ", p2i(start)); 886 while (p < end) { 887 switch (unitsize) { 888 case 1: st->print("%02x", *(u1*)p); break; 889 case 2: st->print("%04x", *(u2*)p); break; 890 case 4: st->print("%08x", *(u4*)p); break; 891 case 8: st->print("%016" FORMAT64_MODIFIER "x", *(u8*)p); break; 892 } 893 p += unitsize; 894 cols++; 895 if (cols >= cols_per_line && p < end) { 896 cols = 0; 897 st->cr(); 898 st->print(PTR_FORMAT ": ", p2i(p)); 899 } else { 900 st->print(" "); 901 } 902 } 903 st->cr(); 904 } 905 906 void os::print_environment_variables(outputStream* st, const char** env_list) { 907 if (env_list) { 908 st->print_cr("Environment Variables:"); 909 910 for (int i = 0; env_list[i] != NULL; i++) { 911 char *envvar = ::getenv(env_list[i]); 912 if (envvar != NULL) { 913 st->print("%s", env_list[i]); 914 st->print("="); 915 st->print_cr("%s", envvar); 916 } 917 } 918 } 919 } 920 921 void os::print_cpu_info(outputStream* st, char* buf, size_t buflen) { 922 // cpu 923 st->print("CPU:"); 924 st->print("total %d", os::processor_count()); 925 // It's not safe to query number of active processors after crash 926 // st->print("(active %d)", os::active_processor_count()); but we can 927 // print the initial number of active processors. 928 // We access the raw value here because the assert in the accessor will 929 // fail if the crash occurs before initialization of this value. 930 st->print(" (initial active %d)", _initial_active_processor_count); 931 st->print(" %s", VM_Version::features_string()); 932 st->cr(); 933 pd_print_cpu_info(st, buf, buflen); 934 } 935 936 // Print a one line string summarizing the cpu, number of cores, memory, and operating system version 937 void os::print_summary_info(outputStream* st, char* buf, size_t buflen) { 938 st->print("Host: "); 939 #ifndef PRODUCT 940 if (get_host_name(buf, buflen)) { 941 st->print("%s, ", buf); 942 } 943 #endif // PRODUCT 944 get_summary_cpu_info(buf, buflen); 945 st->print("%s, ", buf); 946 size_t mem = physical_memory()/G; 947 if (mem == 0) { // for low memory systems 948 mem = physical_memory()/M; 949 st->print("%d cores, " SIZE_FORMAT "M, ", processor_count(), mem); 950 } else { 951 st->print("%d cores, " SIZE_FORMAT "G, ", processor_count(), mem); 952 } 953 get_summary_os_info(buf, buflen); 954 st->print_raw(buf); 955 st->cr(); 956 } 957 958 void os::print_date_and_time(outputStream *st, char* buf, size_t buflen) { 959 const int secs_per_day = 86400; 960 const int secs_per_hour = 3600; 961 const int secs_per_min = 60; 962 963 time_t tloc; 964 (void)time(&tloc); 965 char* timestring = ctime(&tloc); // ctime adds newline. 966 // edit out the newline 967 char* nl = strchr(timestring, '\n'); 968 if (nl != NULL) { 969 *nl = '\0'; 970 } 971 972 struct tm tz; 973 if (localtime_pd(&tloc, &tz) != NULL) { 974 ::strftime(buf, buflen, "%Z", &tz); 975 st->print("Time: %s %s", timestring, buf); 976 } else { 977 st->print("Time: %s", timestring); 978 } 979 980 double t = os::elapsedTime(); 981 // NOTE: It tends to crash after a SEGV if we want to printf("%f",...) in 982 // Linux. Must be a bug in glibc ? Workaround is to round "t" to int 983 // before printf. We lost some precision, but who cares? 984 int eltime = (int)t; // elapsed time in seconds 985 986 // print elapsed time in a human-readable format: 987 int eldays = eltime / secs_per_day; 988 int day_secs = eldays * secs_per_day; 989 int elhours = (eltime - day_secs) / secs_per_hour; 990 int hour_secs = elhours * secs_per_hour; 991 int elmins = (eltime - day_secs - hour_secs) / secs_per_min; 992 int minute_secs = elmins * secs_per_min; 993 int elsecs = (eltime - day_secs - hour_secs - minute_secs); 994 st->print_cr(" elapsed time: %d seconds (%dd %dh %dm %ds)", eltime, eldays, elhours, elmins, elsecs); 995 } 996 997 998 // Check if pointer can be read from (4-byte read access). 999 // Helps to prove validity of a not-NULL pointer. 1000 // Returns true in very early stages of VM life when stub is not yet generated. 1001 #define SAFEFETCH_DEFAULT true 1002 bool os::is_readable_pointer(const void* p) { 1003 if (!CanUseSafeFetch32()) { 1004 return SAFEFETCH_DEFAULT; 1005 } 1006 int* const aligned = (int*) align_down((intptr_t)p, 4); 1007 int cafebabe = 0xcafebabe; // tester value 1 1008 int deadbeef = 0xdeadbeef; // tester value 2 1009 return (SafeFetch32(aligned, cafebabe) != cafebabe) || (SafeFetch32(aligned, deadbeef) != deadbeef); 1010 } 1011 1012 bool os::is_readable_range(const void* from, const void* to) { 1013 for (address p = align_down((address)from, min_page_size()); p < to; p += min_page_size()) { 1014 if (!is_readable_pointer(p)) { 1015 return false; 1016 } 1017 } 1018 return true; 1019 } 1020 1021 1022 // moved from debug.cpp (used to be find()) but still called from there 1023 // The verbose parameter is only set by the debug code in one case 1024 void os::print_location(outputStream* st, intptr_t x, bool verbose) { 1025 address addr = (address)x; 1026 // Handle NULL first, so later checks don't need to protect against it. 1027 if (addr == NULL) { 1028 st->print_cr("0x0 is NULL"); 1029 return; 1030 } 1031 1032 // Check if addr points into a code blob. 1033 CodeBlob* b = CodeCache::find_blob_unsafe(addr); 1034 if (b != NULL) { 1035 b->dump_for_addr(addr, st, verbose); 1036 return; 1037 } 1038 1039 // Check if addr points into Java heap. 1040 if (Universe::heap()->is_in(addr)) { 1041 oop o = oopDesc::oop_or_null(addr); 1042 if (o != NULL) { 1043 if ((HeapWord*)o == (HeapWord*)addr) { 1044 st->print(INTPTR_FORMAT " is an oop: ", p2i(addr)); 1045 } else { 1046 st->print(INTPTR_FORMAT " is pointing into object: " , p2i(addr)); 1047 } 1048 o->print_on(st); 1049 return; 1050 } 1051 } else if (Universe::heap()->is_in_reserved(addr)) { 1052 st->print_cr(INTPTR_FORMAT " is an unallocated location in the heap", p2i(addr)); 1053 return; 1054 } 1055 1056 // Compressed oop needs to be decoded first. 1057 #ifdef _LP64 1058 if (UseCompressedOops && ((uintptr_t)addr &~ (uintptr_t)max_juint) == 0) { 1059 narrowOop narrow_oop = (narrowOop)(uintptr_t)addr; 1060 oop o = oopDesc::decode_oop_raw(narrow_oop); 1061 1062 if (oopDesc::is_valid(o)) { 1063 st->print(UINT32_FORMAT " is a compressed pointer to object: ", narrow_oop); 1064 o->print_on(st); 1065 return; 1066 } 1067 } 1068 #endif 1069 1070 bool accessible = is_readable_pointer(addr); 1071 1072 // Check if addr is a JNI handle. 1073 if (align_down((intptr_t)addr, sizeof(intptr_t)) != 0 && accessible) { 1074 if (JNIHandles::is_global_handle((jobject) addr)) { 1075 st->print_cr(INTPTR_FORMAT " is a global jni handle", p2i(addr)); 1076 return; 1077 } 1078 if (JNIHandles::is_weak_global_handle((jobject) addr)) { 1079 st->print_cr(INTPTR_FORMAT " is a weak global jni handle", p2i(addr)); 1080 return; 1081 } 1082 #ifndef PRODUCT 1083 // we don't keep the block list in product mode 1084 if (JNIHandles::is_local_handle((jobject) addr)) { 1085 st->print_cr(INTPTR_FORMAT " is a local jni handle", p2i(addr)); 1086 return; 1087 } 1088 #endif 1089 } 1090 1091 // Check if addr belongs to a Java thread. 1092 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) { 1093 // If the addr is a java thread print information about that. 1094 if (addr == (address)thread) { 1095 if (verbose) { 1096 thread->print_on(st); 1097 } else { 1098 st->print_cr(INTPTR_FORMAT " is a thread", p2i(addr)); 1099 } 1100 return; 1101 } 1102 // If the addr is in the stack region for this thread then report that 1103 // and print thread info 1104 if (thread->on_local_stack(addr)) { 1105 st->print_cr(INTPTR_FORMAT " is pointing into the stack for thread: " 1106 INTPTR_FORMAT, p2i(addr), p2i(thread)); 1107 if (verbose) thread->print_on(st); 1108 return; 1109 } 1110 } 1111 1112 // Check if in metaspace and print types that have vptrs 1113 if (Metaspace::contains(addr)) { 1114 if (Klass::is_valid((Klass*)addr)) { 1115 st->print_cr(INTPTR_FORMAT " is a pointer to class: ", p2i(addr)); 1116 ((Klass*)addr)->print_on(st); 1117 } else if (Method::is_valid_method((const Method*)addr)) { 1118 ((Method*)addr)->print_value_on(st); 1119 st->cr(); 1120 } else { 1121 // Use addr->print() from the debugger instead (not here) 1122 st->print_cr(INTPTR_FORMAT " is pointing into metadata", p2i(addr)); 1123 } 1124 return; 1125 } 1126 1127 // Compressed klass needs to be decoded first. 1128 #ifdef _LP64 1129 if (UseCompressedClassPointers && ((uintptr_t)addr &~ (uintptr_t)max_juint) == 0) { 1130 narrowKlass narrow_klass = (narrowKlass)(uintptr_t)addr; 1131 Klass* k = Klass::decode_klass_raw(narrow_klass); 1132 1133 if (Klass::is_valid(k)) { 1134 st->print_cr(UINT32_FORMAT " is a compressed pointer to class: " INTPTR_FORMAT, narrow_klass, p2i((HeapWord*)k)); 1135 k->print_on(st); 1136 return; 1137 } 1138 } 1139 #endif 1140 1141 // Try an OS specific find 1142 if (os::find(addr, st)) { 1143 return; 1144 } 1145 1146 if (accessible) { 1147 st->print(INTPTR_FORMAT " points into unknown readable memory:", p2i(addr)); 1148 for (address p = addr; p < align_up(addr + 1, sizeof(intptr_t)); ++p) { 1149 st->print(" %02x", *(u1*)p); 1150 } 1151 st->cr(); 1152 return; 1153 } 1154 1155 st->print_cr(INTPTR_FORMAT " is an unknown value", p2i(addr)); 1156 } 1157 1158 // Looks like all platforms can use the same function to check if C 1159 // stack is walkable beyond current frame. The check for fp() is not 1160 // necessary on Sparc, but it's harmless. 1161 bool os::is_first_C_frame(frame* fr) { 1162 // Load up sp, fp, sender sp and sender fp, check for reasonable values. 1163 // Check usp first, because if that's bad the other accessors may fault 1164 // on some architectures. Ditto ufp second, etc. 1165 uintptr_t fp_align_mask = (uintptr_t)(sizeof(address)-1); 1166 // sp on amd can be 32 bit aligned. 1167 uintptr_t sp_align_mask = (uintptr_t)(sizeof(int)-1); 1168 1169 uintptr_t usp = (uintptr_t)fr->sp(); 1170 if ((usp & sp_align_mask) != 0) return true; 1171 1172 uintptr_t ufp = (uintptr_t)fr->fp(); 1173 if ((ufp & fp_align_mask) != 0) return true; 1174 1175 uintptr_t old_sp = (uintptr_t)fr->sender_sp(); 1176 if ((old_sp & sp_align_mask) != 0) return true; 1177 if (old_sp == 0 || old_sp == (uintptr_t)-1) return true; 1178 1179 uintptr_t old_fp = (uintptr_t)fr->link(); 1180 if ((old_fp & fp_align_mask) != 0) return true; 1181 if (old_fp == 0 || old_fp == (uintptr_t)-1 || old_fp == ufp) return true; 1182 1183 // stack grows downwards; if old_fp is below current fp or if the stack 1184 // frame is too large, either the stack is corrupted or fp is not saved 1185 // on stack (i.e. on x86, ebp may be used as general register). The stack 1186 // is not walkable beyond current frame. 1187 if (old_fp < ufp) return true; 1188 if (old_fp - ufp > 64 * K) return true; 1189 1190 return false; 1191 } 1192 1193 1194 // Set up the boot classpath. 1195 1196 char* os::format_boot_path(const char* format_string, 1197 const char* home, 1198 int home_len, 1199 char fileSep, 1200 char pathSep) { 1201 assert((fileSep == '/' && pathSep == ':') || 1202 (fileSep == '\\' && pathSep == ';'), "unexpected separator chars"); 1203 1204 // Scan the format string to determine the length of the actual 1205 // boot classpath, and handle platform dependencies as well. 1206 int formatted_path_len = 0; 1207 const char* p; 1208 for (p = format_string; *p != 0; ++p) { 1209 if (*p == '%') formatted_path_len += home_len - 1; 1210 ++formatted_path_len; 1211 } 1212 1213 char* formatted_path = NEW_C_HEAP_ARRAY(char, formatted_path_len + 1, mtInternal); 1214 if (formatted_path == NULL) { 1215 return NULL; 1216 } 1217 1218 // Create boot classpath from format, substituting separator chars and 1219 // java home directory. 1220 char* q = formatted_path; 1221 for (p = format_string; *p != 0; ++p) { 1222 switch (*p) { 1223 case '%': 1224 strcpy(q, home); 1225 q += home_len; 1226 break; 1227 case '/': 1228 *q++ = fileSep; 1229 break; 1230 case ':': 1231 *q++ = pathSep; 1232 break; 1233 default: 1234 *q++ = *p; 1235 } 1236 } 1237 *q = '\0'; 1238 1239 assert((q - formatted_path) == formatted_path_len, "formatted_path size botched"); 1240 return formatted_path; 1241 } 1242 1243 // This function is a proxy to fopen, it tries to add a non standard flag ('e' or 'N') 1244 // that ensures automatic closing of the file on exec. If it can not find support in 1245 // the underlying c library, it will make an extra system call (fcntl) to ensure automatic 1246 // closing of the file on exec. 1247 FILE* os::fopen(const char* path, const char* mode) { 1248 char modified_mode[20]; 1249 assert(strlen(mode) + 1 < sizeof(modified_mode), "mode chars plus one extra must fit in buffer"); 1250 sprintf(modified_mode, "%s" LINUX_ONLY("e") BSD_ONLY("e") WINDOWS_ONLY("N"), mode); 1251 FILE* file = ::fopen(path, modified_mode); 1252 1253 #if !(defined LINUX || defined BSD || defined _WINDOWS) 1254 // assume fcntl FD_CLOEXEC support as a backup solution when 'e' or 'N' 1255 // is not supported as mode in fopen 1256 if (file != NULL) { 1257 int fd = fileno(file); 1258 if (fd != -1) { 1259 int fd_flags = fcntl(fd, F_GETFD); 1260 if (fd_flags != -1) { 1261 fcntl(fd, F_SETFD, fd_flags | FD_CLOEXEC); 1262 } 1263 } 1264 } 1265 #endif 1266 1267 return file; 1268 } 1269 1270 bool os::set_boot_path(char fileSep, char pathSep) { 1271 const char* home = Arguments::get_java_home(); 1272 int home_len = (int)strlen(home); 1273 1274 struct stat st; 1275 1276 // modular image if "modules" jimage exists 1277 char* jimage = format_boot_path("%/lib/" MODULES_IMAGE_NAME, home, home_len, fileSep, pathSep); 1278 if (jimage == NULL) return false; 1279 bool has_jimage = (os::stat(jimage, &st) == 0); 1280 if (has_jimage) { 1281 Arguments::set_sysclasspath(jimage, true); 1282 FREE_C_HEAP_ARRAY(char, jimage); 1283 return true; 1284 } 1285 FREE_C_HEAP_ARRAY(char, jimage); 1286 1287 // check if developer build with exploded modules 1288 char* base_classes = format_boot_path("%/modules/" JAVA_BASE_NAME, home, home_len, fileSep, pathSep); 1289 if (base_classes == NULL) return false; 1290 if (os::stat(base_classes, &st) == 0) { 1291 Arguments::set_sysclasspath(base_classes, false); 1292 FREE_C_HEAP_ARRAY(char, base_classes); 1293 return true; 1294 } 1295 FREE_C_HEAP_ARRAY(char, base_classes); 1296 1297 return false; 1298 } 1299 1300 /* 1301 * Splits a path, based on its separator, the number of 1302 * elements is returned back in n. 1303 * It is the callers responsibility to: 1304 * a> check the value of n, and n may be 0. 1305 * b> ignore any empty path elements 1306 * c> free up the data. 1307 */ 1308 char** os::split_path(const char* path, int* n) { 1309 *n = 0; 1310 if (path == NULL || strlen(path) == 0) { 1311 return NULL; 1312 } 1313 const char psepchar = *os::path_separator(); 1314 char* inpath = (char*)NEW_C_HEAP_ARRAY(char, strlen(path) + 1, mtInternal); 1315 if (inpath == NULL) { 1316 return NULL; 1317 } 1318 strcpy(inpath, path); 1319 int count = 1; 1320 char* p = strchr(inpath, psepchar); 1321 // Get a count of elements to allocate memory 1322 while (p != NULL) { 1323 count++; 1324 p++; 1325 p = strchr(p, psepchar); 1326 } 1327 char** opath = (char**) NEW_C_HEAP_ARRAY(char*, count, mtInternal); 1328 if (opath == NULL) { 1329 return NULL; 1330 } 1331 1332 // do the actual splitting 1333 p = inpath; 1334 for (int i = 0 ; i < count ; i++) { 1335 size_t len = strcspn(p, os::path_separator()); 1336 if (len > JVM_MAXPATHLEN) { 1337 return NULL; 1338 } 1339 // allocate the string and add terminator storage 1340 char* s = (char*)NEW_C_HEAP_ARRAY(char, len + 1, mtInternal); 1341 if (s == NULL) { 1342 return NULL; 1343 } 1344 strncpy(s, p, len); 1345 s[len] = '\0'; 1346 opath[i] = s; 1347 p += len + 1; 1348 } 1349 FREE_C_HEAP_ARRAY(char, inpath); 1350 *n = count; 1351 return opath; 1352 } 1353 1354 void os::set_memory_serialize_page(address page) { 1355 int count = log2_intptr(sizeof(class JavaThread)) - log2_intptr(64); 1356 _mem_serialize_page = (volatile int32_t *)page; 1357 // We initialize the serialization page shift count here 1358 // We assume a cache line size of 64 bytes 1359 assert(SerializePageShiftCount == count, "JavaThread size changed; " 1360 "SerializePageShiftCount constant should be %d", count); 1361 set_serialize_page_mask((uintptr_t)(vm_page_size() - sizeof(int32_t))); 1362 } 1363 1364 static volatile intptr_t SerializePageLock = 0; 1365 1366 // This method is called from signal handler when SIGSEGV occurs while the current 1367 // thread tries to store to the "read-only" memory serialize page during state 1368 // transition. 1369 void os::block_on_serialize_page_trap() { 1370 log_debug(safepoint)("Block until the serialize page permission restored"); 1371 1372 // When VMThread is holding the SerializePageLock during modifying the 1373 // access permission of the memory serialize page, the following call 1374 // will block until the permission of that page is restored to rw. 1375 // Generally, it is unsafe to manipulate locks in signal handlers, but in 1376 // this case, it's OK as the signal is synchronous and we know precisely when 1377 // it can occur. 1378 Thread::muxAcquire(&SerializePageLock, "set_memory_serialize_page"); 1379 Thread::muxRelease(&SerializePageLock); 1380 } 1381 1382 // Serialize all thread state variables 1383 void os::serialize_thread_states() { 1384 // On some platforms such as Solaris & Linux, the time duration of the page 1385 // permission restoration is observed to be much longer than expected due to 1386 // scheduler starvation problem etc. To avoid the long synchronization 1387 // time and expensive page trap spinning, 'SerializePageLock' is used to block 1388 // the mutator thread if such case is encountered. See bug 6546278 for details. 1389 Thread::muxAcquire(&SerializePageLock, "serialize_thread_states"); 1390 os::protect_memory((char *)os::get_memory_serialize_page(), 1391 os::vm_page_size(), MEM_PROT_READ); 1392 os::protect_memory((char *)os::get_memory_serialize_page(), 1393 os::vm_page_size(), MEM_PROT_RW); 1394 Thread::muxRelease(&SerializePageLock); 1395 } 1396 1397 // Returns true if the current stack pointer is above the stack shadow 1398 // pages, false otherwise. 1399 bool os::stack_shadow_pages_available(Thread *thread, const methodHandle& method, address sp) { 1400 if (!thread->is_Java_thread()) return false; 1401 // Check if we have StackShadowPages above the yellow zone. This parameter 1402 // is dependent on the depth of the maximum VM call stack possible from 1403 // the handler for stack overflow. 'instanceof' in the stack overflow 1404 // handler or a println uses at least 8k stack of VM and native code 1405 // respectively. 1406 const int framesize_in_bytes = 1407 Interpreter::size_top_interpreter_activation(method()) * wordSize; 1408 1409 address limit = ((JavaThread*)thread)->stack_end() + 1410 (JavaThread::stack_guard_zone_size() + JavaThread::stack_shadow_zone_size()); 1411 1412 return sp > (limit + framesize_in_bytes); 1413 } 1414 1415 size_t os::page_size_for_region(size_t region_size, size_t min_pages, bool must_be_aligned) { 1416 assert(min_pages > 0, "sanity"); 1417 if (UseLargePages) { 1418 const size_t max_page_size = region_size / min_pages; 1419 1420 for (size_t i = 0; _page_sizes[i] != 0; ++i) { 1421 const size_t page_size = _page_sizes[i]; 1422 if (page_size <= max_page_size) { 1423 if (!must_be_aligned || is_aligned(region_size, page_size)) { 1424 return page_size; 1425 } 1426 } 1427 } 1428 } 1429 1430 return vm_page_size(); 1431 } 1432 1433 size_t os::page_size_for_region_aligned(size_t region_size, size_t min_pages) { 1434 return page_size_for_region(region_size, min_pages, true); 1435 } 1436 1437 size_t os::page_size_for_region_unaligned(size_t region_size, size_t min_pages) { 1438 return page_size_for_region(region_size, min_pages, false); 1439 } 1440 1441 static const char* errno_to_string (int e, bool short_text) { 1442 #define ALL_SHARED_ENUMS(X) \ 1443 X(E2BIG, "Argument list too long") \ 1444 X(EACCES, "Permission denied") \ 1445 X(EADDRINUSE, "Address in use") \ 1446 X(EADDRNOTAVAIL, "Address not available") \ 1447 X(EAFNOSUPPORT, "Address family not supported") \ 1448 X(EAGAIN, "Resource unavailable, try again") \ 1449 X(EALREADY, "Connection already in progress") \ 1450 X(EBADF, "Bad file descriptor") \ 1451 X(EBADMSG, "Bad message") \ 1452 X(EBUSY, "Device or resource busy") \ 1453 X(ECANCELED, "Operation canceled") \ 1454 X(ECHILD, "No child processes") \ 1455 X(ECONNABORTED, "Connection aborted") \ 1456 X(ECONNREFUSED, "Connection refused") \ 1457 X(ECONNRESET, "Connection reset") \ 1458 X(EDEADLK, "Resource deadlock would occur") \ 1459 X(EDESTADDRREQ, "Destination address required") \ 1460 X(EDOM, "Mathematics argument out of domain of function") \ 1461 X(EEXIST, "File exists") \ 1462 X(EFAULT, "Bad address") \ 1463 X(EFBIG, "File too large") \ 1464 X(EHOSTUNREACH, "Host is unreachable") \ 1465 X(EIDRM, "Identifier removed") \ 1466 X(EILSEQ, "Illegal byte sequence") \ 1467 X(EINPROGRESS, "Operation in progress") \ 1468 X(EINTR, "Interrupted function") \ 1469 X(EINVAL, "Invalid argument") \ 1470 X(EIO, "I/O error") \ 1471 X(EISCONN, "Socket is connected") \ 1472 X(EISDIR, "Is a directory") \ 1473 X(ELOOP, "Too many levels of symbolic links") \ 1474 X(EMFILE, "Too many open files") \ 1475 X(EMLINK, "Too many links") \ 1476 X(EMSGSIZE, "Message too large") \ 1477 X(ENAMETOOLONG, "Filename too long") \ 1478 X(ENETDOWN, "Network is down") \ 1479 X(ENETRESET, "Connection aborted by network") \ 1480 X(ENETUNREACH, "Network unreachable") \ 1481 X(ENFILE, "Too many files open in system") \ 1482 X(ENOBUFS, "No buffer space available") \ 1483 X(ENODATA, "No message is available on the STREAM head read queue") \ 1484 X(ENODEV, "No such device") \ 1485 X(ENOENT, "No such file or directory") \ 1486 X(ENOEXEC, "Executable file format error") \ 1487 X(ENOLCK, "No locks available") \ 1488 X(ENOLINK, "Reserved") \ 1489 X(ENOMEM, "Not enough space") \ 1490 X(ENOMSG, "No message of the desired type") \ 1491 X(ENOPROTOOPT, "Protocol not available") \ 1492 X(ENOSPC, "No space left on device") \ 1493 X(ENOSR, "No STREAM resources") \ 1494 X(ENOSTR, "Not a STREAM") \ 1495 X(ENOSYS, "Function not supported") \ 1496 X(ENOTCONN, "The socket is not connected") \ 1497 X(ENOTDIR, "Not a directory") \ 1498 X(ENOTEMPTY, "Directory not empty") \ 1499 X(ENOTSOCK, "Not a socket") \ 1500 X(ENOTSUP, "Not supported") \ 1501 X(ENOTTY, "Inappropriate I/O control operation") \ 1502 X(ENXIO, "No such device or address") \ 1503 X(EOPNOTSUPP, "Operation not supported on socket") \ 1504 X(EOVERFLOW, "Value too large to be stored in data type") \ 1505 X(EPERM, "Operation not permitted") \ 1506 X(EPIPE, "Broken pipe") \ 1507 X(EPROTO, "Protocol error") \ 1508 X(EPROTONOSUPPORT, "Protocol not supported") \ 1509 X(EPROTOTYPE, "Protocol wrong type for socket") \ 1510 X(ERANGE, "Result too large") \ 1511 X(EROFS, "Read-only file system") \ 1512 X(ESPIPE, "Invalid seek") \ 1513 X(ESRCH, "No such process") \ 1514 X(ETIME, "Stream ioctl() timeout") \ 1515 X(ETIMEDOUT, "Connection timed out") \ 1516 X(ETXTBSY, "Text file busy") \ 1517 X(EWOULDBLOCK, "Operation would block") \ 1518 X(EXDEV, "Cross-device link") 1519 1520 #define DEFINE_ENTRY(e, text) { e, #e, text }, 1521 1522 static const struct { 1523 int v; 1524 const char* short_text; 1525 const char* long_text; 1526 } table [] = { 1527 1528 ALL_SHARED_ENUMS(DEFINE_ENTRY) 1529 1530 // The following enums are not defined on all platforms. 1531 #ifdef ESTALE 1532 DEFINE_ENTRY(ESTALE, "Reserved") 1533 #endif 1534 #ifdef EDQUOT 1535 DEFINE_ENTRY(EDQUOT, "Reserved") 1536 #endif 1537 #ifdef EMULTIHOP 1538 DEFINE_ENTRY(EMULTIHOP, "Reserved") 1539 #endif 1540 1541 // End marker. 1542 { -1, "Unknown errno", "Unknown error" } 1543 1544 }; 1545 1546 #undef DEFINE_ENTRY 1547 #undef ALL_FLAGS 1548 1549 int i = 0; 1550 while (table[i].v != -1 && table[i].v != e) { 1551 i ++; 1552 } 1553 1554 return short_text ? table[i].short_text : table[i].long_text; 1555 1556 } 1557 1558 const char* os::strerror(int e) { 1559 return errno_to_string(e, false); 1560 } 1561 1562 const char* os::errno_name(int e) { 1563 return errno_to_string(e, true); 1564 } 1565 1566 void os::trace_page_sizes(const char* str, const size_t* page_sizes, int count) { 1567 LogTarget(Info, pagesize) log; 1568 if (log.is_enabled()) { 1569 LogStream out(log); 1570 1571 out.print("%s: ", str); 1572 for (int i = 0; i < count; ++i) { 1573 out.print(" " SIZE_FORMAT, page_sizes[i]); 1574 } 1575 out.cr(); 1576 } 1577 } 1578 1579 #define trace_page_size_params(size) byte_size_in_exact_unit(size), exact_unit_for_byte_size(size) 1580 1581 void os::trace_page_sizes(const char* str, 1582 const size_t region_min_size, 1583 const size_t region_max_size, 1584 const size_t page_size, 1585 const char* base, 1586 const size_t size) { 1587 1588 log_info(pagesize)("%s: " 1589 " min=" SIZE_FORMAT "%s" 1590 " max=" SIZE_FORMAT "%s" 1591 " base=" PTR_FORMAT 1592 " page_size=" SIZE_FORMAT "%s" 1593 " size=" SIZE_FORMAT "%s", 1594 str, 1595 trace_page_size_params(region_min_size), 1596 trace_page_size_params(region_max_size), 1597 p2i(base), 1598 trace_page_size_params(page_size), 1599 trace_page_size_params(size)); 1600 } 1601 1602 void os::trace_page_sizes_for_requested_size(const char* str, 1603 const size_t requested_size, 1604 const size_t page_size, 1605 const size_t alignment, 1606 const char* base, 1607 const size_t size) { 1608 1609 log_info(pagesize)("%s:" 1610 " req_size=" SIZE_FORMAT "%s" 1611 " base=" PTR_FORMAT 1612 " page_size=" SIZE_FORMAT "%s" 1613 " alignment=" SIZE_FORMAT "%s" 1614 " size=" SIZE_FORMAT "%s", 1615 str, 1616 trace_page_size_params(requested_size), 1617 p2i(base), 1618 trace_page_size_params(page_size), 1619 trace_page_size_params(alignment), 1620 trace_page_size_params(size)); 1621 } 1622 1623 1624 // This is the working definition of a server class machine: 1625 // >= 2 physical CPU's and >=2GB of memory, with some fuzz 1626 // because the graphics memory (?) sometimes masks physical memory. 1627 // If you want to change the definition of a server class machine 1628 // on some OS or platform, e.g., >=4GB on Windows platforms, 1629 // then you'll have to parameterize this method based on that state, 1630 // as was done for logical processors here, or replicate and 1631 // specialize this method for each platform. (Or fix os to have 1632 // some inheritance structure and use subclassing. Sigh.) 1633 // If you want some platform to always or never behave as a server 1634 // class machine, change the setting of AlwaysActAsServerClassMachine 1635 // and NeverActAsServerClassMachine in globals*.hpp. 1636 bool os::is_server_class_machine() { 1637 // First check for the early returns 1638 if (NeverActAsServerClassMachine) { 1639 return false; 1640 } 1641 if (AlwaysActAsServerClassMachine) { 1642 return true; 1643 } 1644 // Then actually look at the machine 1645 bool result = false; 1646 const unsigned int server_processors = 2; 1647 const julong server_memory = 2UL * G; 1648 // We seem not to get our full complement of memory. 1649 // We allow some part (1/8?) of the memory to be "missing", 1650 // based on the sizes of DIMMs, and maybe graphics cards. 1651 const julong missing_memory = 256UL * M; 1652 1653 /* Is this a server class machine? */ 1654 if ((os::active_processor_count() >= (int)server_processors) && 1655 (os::physical_memory() >= (server_memory - missing_memory))) { 1656 const unsigned int logical_processors = 1657 VM_Version::logical_processors_per_package(); 1658 if (logical_processors > 1) { 1659 const unsigned int physical_packages = 1660 os::active_processor_count() / logical_processors; 1661 if (physical_packages >= server_processors) { 1662 result = true; 1663 } 1664 } else { 1665 result = true; 1666 } 1667 } 1668 return result; 1669 } 1670 1671 void os::initialize_initial_active_processor_count() { 1672 assert(_initial_active_processor_count == 0, "Initial active processor count already set."); 1673 _initial_active_processor_count = active_processor_count(); 1674 log_debug(os)("Initial active processor count set to %d" , _initial_active_processor_count); 1675 } 1676 1677 void os::SuspendedThreadTask::run() { 1678 internal_do_task(); 1679 _done = true; 1680 } 1681 1682 bool os::create_stack_guard_pages(char* addr, size_t bytes) { 1683 return os::pd_create_stack_guard_pages(addr, bytes); 1684 } 1685 1686 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint, int file_desc) { 1687 char* result = NULL; 1688 1689 if (file_desc != -1) { 1690 // Could have called pd_reserve_memory() followed by replace_existing_mapping_with_file_mapping(), 1691 // but AIX may use SHM in which case its more trouble to detach the segment and remap memory to the file. 1692 result = os::map_memory_to_file(addr, bytes, file_desc); 1693 if (result != NULL) { 1694 MemTracker::record_virtual_memory_reserve_and_commit((address)result, bytes, CALLER_PC); 1695 } 1696 } else { 1697 result = pd_reserve_memory(bytes, addr, alignment_hint); 1698 if (result != NULL) { 1699 MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC); 1700 } 1701 } 1702 1703 return result; 1704 } 1705 1706 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint, 1707 MEMFLAGS flags) { 1708 char* result = pd_reserve_memory(bytes, addr, alignment_hint); 1709 if (result != NULL) { 1710 MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC); 1711 MemTracker::record_virtual_memory_type((address)result, flags); 1712 } 1713 1714 return result; 1715 } 1716 1717 char* os::attempt_reserve_memory_at(size_t bytes, char* addr, int file_desc) { 1718 char* result = NULL; 1719 if (file_desc != -1) { 1720 result = pd_attempt_reserve_memory_at(bytes, addr, file_desc); 1721 if (result != NULL) { 1722 MemTracker::record_virtual_memory_reserve_and_commit((address)result, bytes, CALLER_PC); 1723 } 1724 } else { 1725 result = pd_attempt_reserve_memory_at(bytes, addr); 1726 if (result != NULL) { 1727 MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC); 1728 } 1729 } 1730 return result; 1731 } 1732 1733 void os::split_reserved_memory(char *base, size_t size, 1734 size_t split, bool realloc) { 1735 pd_split_reserved_memory(base, size, split, realloc); 1736 } 1737 1738 bool os::commit_memory(char* addr, size_t bytes, bool executable) { 1739 bool res = pd_commit_memory(addr, bytes, executable); 1740 if (res) { 1741 MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC); 1742 } 1743 return res; 1744 } 1745 1746 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint, 1747 bool executable) { 1748 bool res = os::pd_commit_memory(addr, size, alignment_hint, executable); 1749 if (res) { 1750 MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC); 1751 } 1752 return res; 1753 } 1754 1755 void os::commit_memory_or_exit(char* addr, size_t bytes, bool executable, 1756 const char* mesg) { 1757 pd_commit_memory_or_exit(addr, bytes, executable, mesg); 1758 MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC); 1759 } 1760 1761 void os::commit_memory_or_exit(char* addr, size_t size, size_t alignment_hint, 1762 bool executable, const char* mesg) { 1763 os::pd_commit_memory_or_exit(addr, size, alignment_hint, executable, mesg); 1764 MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC); 1765 } 1766 1767 bool os::uncommit_memory(char* addr, size_t bytes) { 1768 bool res; 1769 if (MemTracker::tracking_level() > NMT_minimal) { 1770 Tracker tkr(Tracker::uncommit); 1771 res = pd_uncommit_memory(addr, bytes); 1772 if (res) { 1773 tkr.record((address)addr, bytes); 1774 } 1775 } else { 1776 res = pd_uncommit_memory(addr, bytes); 1777 } 1778 return res; 1779 } 1780 1781 bool os::release_memory(char* addr, size_t bytes) { 1782 bool res; 1783 if (MemTracker::tracking_level() > NMT_minimal) { 1784 Tracker tkr(Tracker::release); 1785 res = pd_release_memory(addr, bytes); 1786 if (res) { 1787 tkr.record((address)addr, bytes); 1788 } 1789 } else { 1790 res = pd_release_memory(addr, bytes); 1791 } 1792 return res; 1793 } 1794 1795 void os::pretouch_memory(void* start, void* end, size_t page_size) { 1796 for (volatile char *p = (char*)start; p < (char*)end; p += page_size) { 1797 *p = 0; 1798 } 1799 } 1800 1801 char* os::map_memory(int fd, const char* file_name, size_t file_offset, 1802 char *addr, size_t bytes, bool read_only, 1803 bool allow_exec) { 1804 char* result = pd_map_memory(fd, file_name, file_offset, addr, bytes, read_only, allow_exec); 1805 if (result != NULL) { 1806 MemTracker::record_virtual_memory_reserve_and_commit((address)result, bytes, CALLER_PC); 1807 } 1808 return result; 1809 } 1810 1811 char* os::remap_memory(int fd, const char* file_name, size_t file_offset, 1812 char *addr, size_t bytes, bool read_only, 1813 bool allow_exec) { 1814 return pd_remap_memory(fd, file_name, file_offset, addr, bytes, 1815 read_only, allow_exec); 1816 } 1817 1818 bool os::unmap_memory(char *addr, size_t bytes) { 1819 bool result; 1820 if (MemTracker::tracking_level() > NMT_minimal) { 1821 Tracker tkr(Tracker::release); 1822 result = pd_unmap_memory(addr, bytes); 1823 if (result) { 1824 tkr.record((address)addr, bytes); 1825 } 1826 } else { 1827 result = pd_unmap_memory(addr, bytes); 1828 } 1829 return result; 1830 } 1831 1832 void os::free_memory(char *addr, size_t bytes, size_t alignment_hint) { 1833 pd_free_memory(addr, bytes, alignment_hint); 1834 } 1835 1836 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 1837 pd_realign_memory(addr, bytes, alignment_hint); 1838 } 1839 1840 #ifndef _WINDOWS 1841 /* try to switch state from state "from" to state "to" 1842 * returns the state set after the method is complete 1843 */ 1844 os::SuspendResume::State os::SuspendResume::switch_state(os::SuspendResume::State from, 1845 os::SuspendResume::State to) 1846 { 1847 os::SuspendResume::State result = Atomic::cmpxchg(to, &_state, from); 1848 if (result == from) { 1849 // success 1850 return to; 1851 } 1852 return result; 1853 } 1854 #endif