1 /* 2 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 # include "incls/_precompiled.incl" 26 # include "incls/_os.cpp.incl" 27 28 # include <signal.h> 29 30 OSThread* os::_starting_thread = NULL; 31 address os::_polling_page = NULL; 32 volatile int32_t* os::_mem_serialize_page = NULL; 33 uintptr_t os::_serialize_page_mask = 0; 34 long os::_rand_seed = 1; 35 int os::_processor_count = 0; 36 size_t os::_page_sizes[os::page_sizes_max]; 37 38 #ifndef PRODUCT 39 int os::num_mallocs = 0; // # of calls to malloc/realloc 40 size_t os::alloc_bytes = 0; // # of bytes allocated 41 int os::num_frees = 0; // # of calls to free 42 #endif 43 44 // Fill in buffer with current local time as an ISO-8601 string. 45 // E.g., yyyy-mm-ddThh:mm:ss-zzzz. 46 // Returns buffer, or NULL if it failed. 47 // This would mostly be a call to 48 // strftime(...., "%Y-%m-%d" "T" "%H:%M:%S" "%z", ....) 49 // except that on Windows the %z behaves badly, so we do it ourselves. 50 // Also, people wanted milliseconds on there, 51 // and strftime doesn't do milliseconds. 52 char* os::iso8601_time(char* buffer, size_t buffer_length) { 53 // Output will be of the form "YYYY-MM-DDThh:mm:ss.mmm+zzzz\0" 54 // 1 2 55 // 12345678901234567890123456789 56 static const char* iso8601_format = 57 "%04d-%02d-%02dT%02d:%02d:%02d.%03d%c%02d%02d"; 58 static const size_t needed_buffer = 29; 59 60 // Sanity check the arguments 61 if (buffer == NULL) { 62 assert(false, "NULL buffer"); 63 return NULL; 64 } 65 if (buffer_length < needed_buffer) { 66 assert(false, "buffer_length too small"); 67 return NULL; 68 } 69 // Get the current time 70 jlong milliseconds_since_19700101 = javaTimeMillis(); 71 const int milliseconds_per_microsecond = 1000; 72 const time_t seconds_since_19700101 = 73 milliseconds_since_19700101 / milliseconds_per_microsecond; 74 const int milliseconds_after_second = 75 milliseconds_since_19700101 % milliseconds_per_microsecond; 76 // Convert the time value to a tm and timezone variable 77 struct tm time_struct; 78 if (localtime_pd(&seconds_since_19700101, &time_struct) == NULL) { 79 assert(false, "Failed localtime_pd"); 80 return NULL; 81 } 82 const time_t zone = timezone; 83 84 // If daylight savings time is in effect, 85 // we are 1 hour East of our time zone 86 const time_t seconds_per_minute = 60; 87 const time_t minutes_per_hour = 60; 88 const time_t seconds_per_hour = seconds_per_minute * minutes_per_hour; 89 time_t UTC_to_local = zone; 90 if (time_struct.tm_isdst > 0) { 91 UTC_to_local = UTC_to_local - seconds_per_hour; 92 } 93 // Compute the time zone offset. 94 // localtime_pd() sets timezone to the difference (in seconds) 95 // between UTC and and local time. 96 // ISO 8601 says we need the difference between local time and UTC, 97 // we change the sign of the localtime_pd() result. 98 const time_t local_to_UTC = -(UTC_to_local); 99 // Then we have to figure out if if we are ahead (+) or behind (-) UTC. 100 char sign_local_to_UTC = '+'; 101 time_t abs_local_to_UTC = local_to_UTC; 102 if (local_to_UTC < 0) { 103 sign_local_to_UTC = '-'; 104 abs_local_to_UTC = -(abs_local_to_UTC); 105 } 106 // Convert time zone offset seconds to hours and minutes. 107 const time_t zone_hours = (abs_local_to_UTC / seconds_per_hour); 108 const time_t zone_min = 109 ((abs_local_to_UTC % seconds_per_hour) / seconds_per_minute); 110 111 // Print an ISO 8601 date and time stamp into the buffer 112 const int year = 1900 + time_struct.tm_year; 113 const int month = 1 + time_struct.tm_mon; 114 const int printed = jio_snprintf(buffer, buffer_length, iso8601_format, 115 year, 116 month, 117 time_struct.tm_mday, 118 time_struct.tm_hour, 119 time_struct.tm_min, 120 time_struct.tm_sec, 121 milliseconds_after_second, 122 sign_local_to_UTC, 123 zone_hours, 124 zone_min); 125 if (printed == 0) { 126 assert(false, "Failed jio_printf"); 127 return NULL; 128 } 129 return buffer; 130 } 131 132 OSReturn os::set_priority(Thread* thread, ThreadPriority p) { 133 #ifdef ASSERT 134 if (!(!thread->is_Java_thread() || 135 Thread::current() == thread || 136 Threads_lock->owned_by_self() 137 || thread->is_Compiler_thread() 138 )) { 139 assert(false, "possibility of dangling Thread pointer"); 140 } 141 #endif 142 143 if (p >= MinPriority && p <= MaxPriority) { 144 int priority = java_to_os_priority[p]; 145 return set_native_priority(thread, priority); 146 } else { 147 assert(false, "Should not happen"); 148 return OS_ERR; 149 } 150 } 151 152 153 OSReturn os::get_priority(const Thread* const thread, ThreadPriority& priority) { 154 int p; 155 int os_prio; 156 OSReturn ret = get_native_priority(thread, &os_prio); 157 if (ret != OS_OK) return ret; 158 159 for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] > os_prio; p--) ; 160 priority = (ThreadPriority)p; 161 return OS_OK; 162 } 163 164 165 // --------------------- sun.misc.Signal (optional) --------------------- 166 167 168 // SIGBREAK is sent by the keyboard to query the VM state 169 #ifndef SIGBREAK 170 #define SIGBREAK SIGQUIT 171 #endif 172 173 // sigexitnum_pd is a platform-specific special signal used for terminating the Signal thread. 174 175 176 static void signal_thread_entry(JavaThread* thread, TRAPS) { 177 os::set_priority(thread, NearMaxPriority); 178 while (true) { 179 int sig; 180 { 181 // FIXME : Currently we have not decieded what should be the status 182 // for this java thread blocked here. Once we decide about 183 // that we should fix this. 184 sig = os::signal_wait(); 185 } 186 if (sig == os::sigexitnum_pd()) { 187 // Terminate the signal thread 188 return; 189 } 190 191 switch (sig) { 192 case SIGBREAK: { 193 // Check if the signal is a trigger to start the Attach Listener - in that 194 // case don't print stack traces. 195 if (!DisableAttachMechanism && AttachListener::is_init_trigger()) { 196 continue; 197 } 198 // Print stack traces 199 // Any SIGBREAK operations added here should make sure to flush 200 // the output stream (e.g. tty->flush()) after output. See 4803766. 201 // Each module also prints an extra carriage return after its output. 202 VM_PrintThreads op; 203 VMThread::execute(&op); 204 VM_PrintJNI jni_op; 205 VMThread::execute(&jni_op); 206 VM_FindDeadlocks op1(tty); 207 VMThread::execute(&op1); 208 Universe::print_heap_at_SIGBREAK(); 209 if (PrintClassHistogram) { 210 VM_GC_HeapInspection op1(gclog_or_tty, true /* force full GC before heap inspection */, 211 true /* need_prologue */); 212 VMThread::execute(&op1); 213 } 214 if (JvmtiExport::should_post_data_dump()) { 215 JvmtiExport::post_data_dump(); 216 } 217 break; 218 } 219 default: { 220 // Dispatch the signal to java 221 HandleMark hm(THREAD); 222 klassOop k = SystemDictionary::resolve_or_null(vmSymbolHandles::sun_misc_Signal(), THREAD); 223 KlassHandle klass (THREAD, k); 224 if (klass.not_null()) { 225 JavaValue result(T_VOID); 226 JavaCallArguments args; 227 args.push_int(sig); 228 JavaCalls::call_static( 229 &result, 230 klass, 231 vmSymbolHandles::dispatch_name(), 232 vmSymbolHandles::int_void_signature(), 233 &args, 234 THREAD 235 ); 236 } 237 if (HAS_PENDING_EXCEPTION) { 238 // tty is initialized early so we don't expect it to be null, but 239 // if it is we can't risk doing an initialization that might 240 // trigger additional out-of-memory conditions 241 if (tty != NULL) { 242 char klass_name[256]; 243 char tmp_sig_name[16]; 244 const char* sig_name = "UNKNOWN"; 245 instanceKlass::cast(PENDING_EXCEPTION->klass())-> 246 name()->as_klass_external_name(klass_name, 256); 247 if (os::exception_name(sig, tmp_sig_name, 16) != NULL) 248 sig_name = tmp_sig_name; 249 warning("Exception %s occurred dispatching signal %s to handler" 250 "- the VM may need to be forcibly terminated", 251 klass_name, sig_name ); 252 } 253 CLEAR_PENDING_EXCEPTION; 254 } 255 } 256 } 257 } 258 } 259 260 261 void os::signal_init() { 262 if (!ReduceSignalUsage) { 263 // Setup JavaThread for processing signals 264 EXCEPTION_MARK; 265 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK); 266 instanceKlassHandle klass (THREAD, k); 267 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 268 269 const char thread_name[] = "Signal Dispatcher"; 270 Handle string = java_lang_String::create_from_str(thread_name, CHECK); 271 272 // Initialize thread_oop to put it into the system threadGroup 273 Handle thread_group (THREAD, Universe::system_thread_group()); 274 JavaValue result(T_VOID); 275 JavaCalls::call_special(&result, thread_oop, 276 klass, 277 vmSymbolHandles::object_initializer_name(), 278 vmSymbolHandles::threadgroup_string_void_signature(), 279 thread_group, 280 string, 281 CHECK); 282 283 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass()); 284 JavaCalls::call_special(&result, 285 thread_group, 286 group, 287 vmSymbolHandles::add_method_name(), 288 vmSymbolHandles::thread_void_signature(), 289 thread_oop, // ARG 1 290 CHECK); 291 292 os::signal_init_pd(); 293 294 { MutexLocker mu(Threads_lock); 295 JavaThread* signal_thread = new JavaThread(&signal_thread_entry); 296 297 // At this point it may be possible that no osthread was created for the 298 // JavaThread due to lack of memory. We would have to throw an exception 299 // in that case. However, since this must work and we do not allow 300 // exceptions anyway, check and abort if this fails. 301 if (signal_thread == NULL || signal_thread->osthread() == NULL) { 302 vm_exit_during_initialization("java.lang.OutOfMemoryError", 303 "unable to create new native thread"); 304 } 305 306 java_lang_Thread::set_thread(thread_oop(), signal_thread); 307 java_lang_Thread::set_priority(thread_oop(), NearMaxPriority); 308 java_lang_Thread::set_daemon(thread_oop()); 309 310 signal_thread->set_threadObj(thread_oop()); 311 Threads::add(signal_thread); 312 Thread::start(signal_thread); 313 } 314 // Handle ^BREAK 315 os::signal(SIGBREAK, os::user_handler()); 316 } 317 } 318 319 320 void os::terminate_signal_thread() { 321 if (!ReduceSignalUsage) 322 signal_notify(sigexitnum_pd()); 323 } 324 325 326 // --------------------- loading libraries --------------------- 327 328 typedef jint (JNICALL *JNI_OnLoad_t)(JavaVM *, void *); 329 extern struct JavaVM_ main_vm; 330 331 static void* _native_java_library = NULL; 332 333 void* os::native_java_library() { 334 if (_native_java_library == NULL) { 335 char buffer[JVM_MAXPATHLEN]; 336 char ebuf[1024]; 337 338 // Try to load verify dll first. In 1.3 java dll depends on it and is not 339 // always able to find it when the loading executable is outside the JDK. 340 // In order to keep working with 1.2 we ignore any loading errors. 341 dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), "verify"); 342 dll_load(buffer, ebuf, sizeof(ebuf)); 343 344 // Load java dll 345 dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), "java"); 346 _native_java_library = dll_load(buffer, ebuf, sizeof(ebuf)); 347 if (_native_java_library == NULL) { 348 vm_exit_during_initialization("Unable to load native library", ebuf); 349 } 350 } 351 static jboolean onLoaded = JNI_FALSE; 352 if (onLoaded) { 353 // We may have to wait to fire OnLoad until TLS is initialized. 354 if (ThreadLocalStorage::is_initialized()) { 355 // The JNI_OnLoad handling is normally done by method load in 356 // java.lang.ClassLoader$NativeLibrary, but the VM loads the base library 357 // explicitly so we have to check for JNI_OnLoad as well 358 const char *onLoadSymbols[] = JNI_ONLOAD_SYMBOLS; 359 JNI_OnLoad_t JNI_OnLoad = CAST_TO_FN_PTR( 360 JNI_OnLoad_t, dll_lookup(_native_java_library, onLoadSymbols[0])); 361 if (JNI_OnLoad != NULL) { 362 JavaThread* thread = JavaThread::current(); 363 ThreadToNativeFromVM ttn(thread); 364 HandleMark hm(thread); 365 jint ver = (*JNI_OnLoad)(&main_vm, NULL); 366 onLoaded = JNI_TRUE; 367 if (!Threads::is_supported_jni_version_including_1_1(ver)) { 368 vm_exit_during_initialization("Unsupported JNI version"); 369 } 370 } 371 } 372 } 373 return _native_java_library; 374 } 375 376 // --------------------- heap allocation utilities --------------------- 377 378 char *os::strdup(const char *str) { 379 size_t size = strlen(str); 380 char *dup_str = (char *)malloc(size + 1); 381 if (dup_str == NULL) return NULL; 382 strcpy(dup_str, str); 383 return dup_str; 384 } 385 386 387 388 #ifdef ASSERT 389 #define space_before (MallocCushion + sizeof(double)) 390 #define space_after MallocCushion 391 #define size_addr_from_base(p) (size_t*)(p + space_before - sizeof(size_t)) 392 #define size_addr_from_obj(p) ((size_t*)p - 1) 393 // MallocCushion: size of extra cushion allocated around objects with +UseMallocOnly 394 // NB: cannot be debug variable, because these aren't set from the command line until 395 // *after* the first few allocs already happened 396 #define MallocCushion 16 397 #else 398 #define space_before 0 399 #define space_after 0 400 #define size_addr_from_base(p) should not use w/o ASSERT 401 #define size_addr_from_obj(p) should not use w/o ASSERT 402 #define MallocCushion 0 403 #endif 404 #define paranoid 0 /* only set to 1 if you suspect checking code has bug */ 405 406 #ifdef ASSERT 407 inline size_t get_size(void* obj) { 408 size_t size = *size_addr_from_obj(obj); 409 if (size < 0) { 410 fatal(err_msg("free: size field of object #" PTR_FORMAT " was overwritten (" 411 SIZE_FORMAT ")", obj, size)); 412 } 413 return size; 414 } 415 416 u_char* find_cushion_backwards(u_char* start) { 417 u_char* p = start; 418 while (p[ 0] != badResourceValue || p[-1] != badResourceValue || 419 p[-2] != badResourceValue || p[-3] != badResourceValue) p--; 420 // ok, we have four consecutive marker bytes; find start 421 u_char* q = p - 4; 422 while (*q == badResourceValue) q--; 423 return q + 1; 424 } 425 426 u_char* find_cushion_forwards(u_char* start) { 427 u_char* p = start; 428 while (p[0] != badResourceValue || p[1] != badResourceValue || 429 p[2] != badResourceValue || p[3] != badResourceValue) p++; 430 // ok, we have four consecutive marker bytes; find end of cushion 431 u_char* q = p + 4; 432 while (*q == badResourceValue) q++; 433 return q - MallocCushion; 434 } 435 436 void print_neighbor_blocks(void* ptr) { 437 // find block allocated before ptr (not entirely crash-proof) 438 if (MallocCushion < 4) { 439 tty->print_cr("### cannot find previous block (MallocCushion < 4)"); 440 return; 441 } 442 u_char* start_of_this_block = (u_char*)ptr - space_before; 443 u_char* end_of_prev_block_data = start_of_this_block - space_after -1; 444 // look for cushion in front of prev. block 445 u_char* start_of_prev_block = find_cushion_backwards(end_of_prev_block_data); 446 ptrdiff_t size = *size_addr_from_base(start_of_prev_block); 447 u_char* obj = start_of_prev_block + space_before; 448 if (size <= 0 ) { 449 // start is bad; mayhave been confused by OS data inbetween objects 450 // search one more backwards 451 start_of_prev_block = find_cushion_backwards(start_of_prev_block); 452 size = *size_addr_from_base(start_of_prev_block); 453 obj = start_of_prev_block + space_before; 454 } 455 456 if (start_of_prev_block + space_before + size + space_after == start_of_this_block) { 457 tty->print_cr("### previous object: %p (%ld bytes)", obj, size); 458 } else { 459 tty->print_cr("### previous object (not sure if correct): %p (%ld bytes)", obj, size); 460 } 461 462 // now find successor block 463 u_char* start_of_next_block = (u_char*)ptr + *size_addr_from_obj(ptr) + space_after; 464 start_of_next_block = find_cushion_forwards(start_of_next_block); 465 u_char* next_obj = start_of_next_block + space_before; 466 ptrdiff_t next_size = *size_addr_from_base(start_of_next_block); 467 if (start_of_next_block[0] == badResourceValue && 468 start_of_next_block[1] == badResourceValue && 469 start_of_next_block[2] == badResourceValue && 470 start_of_next_block[3] == badResourceValue) { 471 tty->print_cr("### next object: %p (%ld bytes)", next_obj, next_size); 472 } else { 473 tty->print_cr("### next object (not sure if correct): %p (%ld bytes)", next_obj, next_size); 474 } 475 } 476 477 478 void report_heap_error(void* memblock, void* bad, const char* where) { 479 tty->print_cr("## nof_mallocs = %d, nof_frees = %d", os::num_mallocs, os::num_frees); 480 tty->print_cr("## memory stomp: byte at %p %s object %p", bad, where, memblock); 481 print_neighbor_blocks(memblock); 482 fatal("memory stomping error"); 483 } 484 485 void verify_block(void* memblock) { 486 size_t size = get_size(memblock); 487 if (MallocCushion) { 488 u_char* ptr = (u_char*)memblock - space_before; 489 for (int i = 0; i < MallocCushion; i++) { 490 if (ptr[i] != badResourceValue) { 491 report_heap_error(memblock, ptr+i, "in front of"); 492 } 493 } 494 u_char* end = (u_char*)memblock + size + space_after; 495 for (int j = -MallocCushion; j < 0; j++) { 496 if (end[j] != badResourceValue) { 497 report_heap_error(memblock, end+j, "after"); 498 } 499 } 500 } 501 } 502 #endif 503 504 void* os::malloc(size_t size) { 505 NOT_PRODUCT(num_mallocs++); 506 NOT_PRODUCT(alloc_bytes += size); 507 508 if (size == 0) { 509 // return a valid pointer if size is zero 510 // if NULL is returned the calling functions assume out of memory. 511 size = 1; 512 } 513 514 NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap()); 515 u_char* ptr = (u_char*)::malloc(size + space_before + space_after); 516 #ifdef ASSERT 517 if (ptr == NULL) return NULL; 518 if (MallocCushion) { 519 for (u_char* p = ptr; p < ptr + MallocCushion; p++) *p = (u_char)badResourceValue; 520 u_char* end = ptr + space_before + size; 521 for (u_char* pq = ptr+MallocCushion; pq < end; pq++) *pq = (u_char)uninitBlockPad; 522 for (u_char* q = end; q < end + MallocCushion; q++) *q = (u_char)badResourceValue; 523 } 524 // put size just before data 525 *size_addr_from_base(ptr) = size; 526 #endif 527 u_char* memblock = ptr + space_before; 528 if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) { 529 tty->print_cr("os::malloc caught, %lu bytes --> %p", size, memblock); 530 breakpoint(); 531 } 532 debug_only(if (paranoid) verify_block(memblock)); 533 if (PrintMalloc && tty != NULL) tty->print_cr("os::malloc %lu bytes --> %p", size, memblock); 534 return memblock; 535 } 536 537 538 void* os::realloc(void *memblock, size_t size) { 539 NOT_PRODUCT(num_mallocs++); 540 NOT_PRODUCT(alloc_bytes += size); 541 #ifndef ASSERT 542 return ::realloc(memblock, size); 543 #else 544 if (memblock == NULL) { 545 return os::malloc(size); 546 } 547 if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) { 548 tty->print_cr("os::realloc caught %p", memblock); 549 breakpoint(); 550 } 551 verify_block(memblock); 552 NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap()); 553 if (size == 0) return NULL; 554 // always move the block 555 void* ptr = malloc(size); 556 if (PrintMalloc) tty->print_cr("os::remalloc %lu bytes, %p --> %p", size, memblock, ptr); 557 // Copy to new memory if malloc didn't fail 558 if ( ptr != NULL ) { 559 memcpy(ptr, memblock, MIN2(size, get_size(memblock))); 560 if (paranoid) verify_block(ptr); 561 if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) { 562 tty->print_cr("os::realloc caught, %lu bytes --> %p", size, ptr); 563 breakpoint(); 564 } 565 free(memblock); 566 } 567 return ptr; 568 #endif 569 } 570 571 572 void os::free(void *memblock) { 573 NOT_PRODUCT(num_frees++); 574 #ifdef ASSERT 575 if (memblock == NULL) return; 576 if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) { 577 if (tty != NULL) tty->print_cr("os::free caught %p", memblock); 578 breakpoint(); 579 } 580 verify_block(memblock); 581 if (PrintMalloc && tty != NULL) 582 // tty->print_cr("os::free %p", memblock); 583 fprintf(stderr, "os::free %p\n", memblock); 584 NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap()); 585 // Added by detlefs. 586 if (MallocCushion) { 587 u_char* ptr = (u_char*)memblock - space_before; 588 for (u_char* p = ptr; p < ptr + MallocCushion; p++) { 589 guarantee(*p == badResourceValue, 590 "Thing freed should be malloc result."); 591 *p = (u_char)freeBlockPad; 592 } 593 size_t size = get_size(memblock); 594 u_char* end = ptr + space_before + size; 595 for (u_char* q = end; q < end + MallocCushion; q++) { 596 guarantee(*q == badResourceValue, 597 "Thing freed should be malloc result."); 598 *q = (u_char)freeBlockPad; 599 } 600 } 601 #endif 602 ::free((char*)memblock - space_before); 603 } 604 605 void os::init_random(long initval) { 606 _rand_seed = initval; 607 } 608 609 610 long os::random() { 611 /* standard, well-known linear congruential random generator with 612 * next_rand = (16807*seed) mod (2**31-1) 613 * see 614 * (1) "Random Number Generators: Good Ones Are Hard to Find", 615 * S.K. Park and K.W. Miller, Communications of the ACM 31:10 (Oct 1988), 616 * (2) "Two Fast Implementations of the 'Minimal Standard' Random 617 * Number Generator", David G. Carta, Comm. ACM 33, 1 (Jan 1990), pp. 87-88. 618 */ 619 const long a = 16807; 620 const unsigned long m = 2147483647; 621 const long q = m / a; assert(q == 127773, "weird math"); 622 const long r = m % a; assert(r == 2836, "weird math"); 623 624 // compute az=2^31p+q 625 unsigned long lo = a * (long)(_rand_seed & 0xFFFF); 626 unsigned long hi = a * (long)((unsigned long)_rand_seed >> 16); 627 lo += (hi & 0x7FFF) << 16; 628 629 // if q overflowed, ignore the overflow and increment q 630 if (lo > m) { 631 lo &= m; 632 ++lo; 633 } 634 lo += hi >> 15; 635 636 // if (p+q) overflowed, ignore the overflow and increment (p+q) 637 if (lo > m) { 638 lo &= m; 639 ++lo; 640 } 641 return (_rand_seed = lo); 642 } 643 644 // The INITIALIZED state is distinguished from the SUSPENDED state because the 645 // conditions in which a thread is first started are different from those in which 646 // a suspension is resumed. These differences make it hard for us to apply the 647 // tougher checks when starting threads that we want to do when resuming them. 648 // However, when start_thread is called as a result of Thread.start, on a Java 649 // thread, the operation is synchronized on the Java Thread object. So there 650 // cannot be a race to start the thread and hence for the thread to exit while 651 // we are working on it. Non-Java threads that start Java threads either have 652 // to do so in a context in which races are impossible, or should do appropriate 653 // locking. 654 655 void os::start_thread(Thread* thread) { 656 // guard suspend/resume 657 MutexLockerEx ml(thread->SR_lock(), Mutex::_no_safepoint_check_flag); 658 OSThread* osthread = thread->osthread(); 659 osthread->set_state(RUNNABLE); 660 pd_start_thread(thread); 661 } 662 663 //--------------------------------------------------------------------------- 664 // Helper functions for fatal error handler 665 666 void os::print_hex_dump(outputStream* st, address start, address end, int unitsize) { 667 assert(unitsize == 1 || unitsize == 2 || unitsize == 4 || unitsize == 8, "just checking"); 668 669 int cols = 0; 670 int cols_per_line = 0; 671 switch (unitsize) { 672 case 1: cols_per_line = 16; break; 673 case 2: cols_per_line = 8; break; 674 case 4: cols_per_line = 4; break; 675 case 8: cols_per_line = 2; break; 676 default: return; 677 } 678 679 address p = start; 680 st->print(PTR_FORMAT ": ", start); 681 while (p < end) { 682 switch (unitsize) { 683 case 1: st->print("%02x", *(u1*)p); break; 684 case 2: st->print("%04x", *(u2*)p); break; 685 case 4: st->print("%08x", *(u4*)p); break; 686 case 8: st->print("%016" FORMAT64_MODIFIER "x", *(u8*)p); break; 687 } 688 p += unitsize; 689 cols++; 690 if (cols >= cols_per_line && p < end) { 691 cols = 0; 692 st->cr(); 693 st->print(PTR_FORMAT ": ", p); 694 } else { 695 st->print(" "); 696 } 697 } 698 st->cr(); 699 } 700 701 void os::print_environment_variables(outputStream* st, const char** env_list, 702 char* buffer, int len) { 703 if (env_list) { 704 st->print_cr("Environment Variables:"); 705 706 for (int i = 0; env_list[i] != NULL; i++) { 707 if (getenv(env_list[i], buffer, len)) { 708 st->print(env_list[i]); 709 st->print("="); 710 st->print_cr(buffer); 711 } 712 } 713 } 714 } 715 716 void os::print_cpu_info(outputStream* st) { 717 // cpu 718 st->print("CPU:"); 719 st->print("total %d", os::processor_count()); 720 // It's not safe to query number of active processors after crash 721 // st->print("(active %d)", os::active_processor_count()); 722 st->print(" %s", VM_Version::cpu_features()); 723 st->cr(); 724 } 725 726 void os::print_date_and_time(outputStream *st) { 727 time_t tloc; 728 (void)time(&tloc); 729 st->print("time: %s", ctime(&tloc)); // ctime adds newline. 730 731 double t = os::elapsedTime(); 732 // NOTE: It tends to crash after a SEGV if we want to printf("%f",...) in 733 // Linux. Must be a bug in glibc ? Workaround is to round "t" to int 734 // before printf. We lost some precision, but who cares? 735 st->print_cr("elapsed time: %d seconds", (int)t); 736 } 737 738 // moved from debug.cpp (used to be find()) but still called from there 739 // The verbose parameter is only set by the debug code in one case 740 void os::print_location(outputStream* st, intptr_t x, bool verbose) { 741 address addr = (address)x; 742 CodeBlob* b = CodeCache::find_blob_unsafe(addr); 743 if (b != NULL) { 744 if (b->is_buffer_blob()) { 745 // the interpreter is generated into a buffer blob 746 InterpreterCodelet* i = Interpreter::codelet_containing(addr); 747 if (i != NULL) { 748 st->print_cr(INTPTR_FORMAT " is an Interpreter codelet", addr); 749 i->print_on(st); 750 return; 751 } 752 if (Interpreter::contains(addr)) { 753 st->print_cr(INTPTR_FORMAT " is pointing into interpreter code" 754 " (not bytecode specific)", addr); 755 return; 756 } 757 // 758 if (AdapterHandlerLibrary::contains(b)) { 759 st->print_cr(INTPTR_FORMAT " is an AdapterHandler", addr); 760 AdapterHandlerLibrary::print_handler_on(st, b); 761 } 762 // the stubroutines are generated into a buffer blob 763 StubCodeDesc* d = StubCodeDesc::desc_for(addr); 764 if (d != NULL) { 765 d->print_on(st); 766 if (verbose) st->cr(); 767 return; 768 } 769 if (StubRoutines::contains(addr)) { 770 st->print_cr(INTPTR_FORMAT " is pointing to an (unnamed) " 771 "stub routine", addr); 772 return; 773 } 774 // the InlineCacheBuffer is using stubs generated into a buffer blob 775 if (InlineCacheBuffer::contains(addr)) { 776 st->print_cr(INTPTR_FORMAT " is pointing into InlineCacheBuffer", addr); 777 return; 778 } 779 VtableStub* v = VtableStubs::stub_containing(addr); 780 if (v != NULL) { 781 v->print_on(st); 782 return; 783 } 784 } 785 if (verbose && b->is_nmethod()) { 786 ResourceMark rm; 787 st->print("%#p: Compiled ", addr); 788 ((nmethod*)b)->method()->print_value_on(st); 789 st->print(" = (CodeBlob*)" INTPTR_FORMAT, b); 790 st->cr(); 791 return; 792 } 793 if ( b->is_nmethod()) { 794 if (b->is_zombie()) { 795 st->print_cr(INTPTR_FORMAT " is zombie nmethod", b); 796 } else if (b->is_not_entrant()) { 797 st->print_cr(INTPTR_FORMAT " is non-entrant nmethod", b); 798 } 799 } 800 b->print_on(st); 801 return; 802 } 803 804 if (Universe::heap()->is_in(addr)) { 805 HeapWord* p = Universe::heap()->block_start(addr); 806 bool print = false; 807 // If we couldn't find it it just may mean that heap wasn't parseable 808 // See if we were just given an oop directly 809 if (p != NULL && Universe::heap()->block_is_obj(p)) { 810 print = true; 811 } else if (p == NULL && ((oopDesc*)addr)->is_oop()) { 812 p = (HeapWord*) addr; 813 print = true; 814 } 815 if (print) { 816 st->print_cr(INTPTR_FORMAT " is an oop", addr); 817 oop(p)->print_on(st); 818 if (p != (HeapWord*)x && oop(p)->is_constMethod() && 819 constMethodOop(p)->contains(addr)) { 820 Thread *thread = Thread::current(); 821 HandleMark hm(thread); 822 methodHandle mh (thread, constMethodOop(p)->method()); 823 if (!mh->is_native()) { 824 st->print_cr("bci_from(%p) = %d; print_codes():", 825 addr, mh->bci_from(address(x))); 826 mh->print_codes_on(st); 827 } 828 } 829 return; 830 } 831 } else { 832 if (Universe::heap()->is_in_reserved(addr)) { 833 st->print_cr(INTPTR_FORMAT " is an unallocated location " 834 "in the heap", addr); 835 return; 836 } 837 } 838 if (JNIHandles::is_global_handle((jobject) addr)) { 839 st->print_cr(INTPTR_FORMAT " is a global jni handle", addr); 840 return; 841 } 842 if (JNIHandles::is_weak_global_handle((jobject) addr)) { 843 st->print_cr(INTPTR_FORMAT " is a weak global jni handle", addr); 844 return; 845 } 846 #ifndef PRODUCT 847 // we don't keep the block list in product mode 848 if (JNIHandleBlock::any_contains((jobject) addr)) { 849 st->print_cr(INTPTR_FORMAT " is a local jni handle", addr); 850 return; 851 } 852 #endif 853 854 for(JavaThread *thread = Threads::first(); thread; thread = thread->next()) { 855 // Check for privilege stack 856 if (thread->privileged_stack_top() != NULL && 857 thread->privileged_stack_top()->contains(addr)) { 858 st->print_cr(INTPTR_FORMAT " is pointing into the privilege stack " 859 "for thread: " INTPTR_FORMAT, addr, thread); 860 if (verbose) thread->print_on(st); 861 return; 862 } 863 // If the addr is a java thread print information about that. 864 if (addr == (address)thread) { 865 if (verbose) { 866 thread->print_on(st); 867 } else { 868 st->print_cr(INTPTR_FORMAT " is a thread", addr); 869 } 870 return; 871 } 872 // If the addr is in the stack region for this thread then report that 873 // and print thread info 874 if (thread->stack_base() >= addr && 875 addr > (thread->stack_base() - thread->stack_size())) { 876 st->print_cr(INTPTR_FORMAT " is pointing into the stack for thread: " 877 INTPTR_FORMAT, addr, thread); 878 if (verbose) thread->print_on(st); 879 return; 880 } 881 882 } 883 // Try an OS specific find 884 if (os::find(addr, st)) { 885 return; 886 } 887 888 st->print_cr(INTPTR_FORMAT " is an unknown value", addr); 889 } 890 891 // Looks like all platforms except IA64 can use the same function to check 892 // if C stack is walkable beyond current frame. The check for fp() is not 893 // necessary on Sparc, but it's harmless. 894 bool os::is_first_C_frame(frame* fr) { 895 #ifdef IA64 896 // In order to walk native frames on Itanium, we need to access the unwind 897 // table, which is inside ELF. We don't want to parse ELF after fatal error, 898 // so return true for IA64. If we need to support C stack walking on IA64, 899 // this function needs to be moved to CPU specific files, as fp() on IA64 900 // is register stack, which grows towards higher memory address. 901 return true; 902 #endif 903 904 // Load up sp, fp, sender sp and sender fp, check for reasonable values. 905 // Check usp first, because if that's bad the other accessors may fault 906 // on some architectures. Ditto ufp second, etc. 907 uintptr_t fp_align_mask = (uintptr_t)(sizeof(address)-1); 908 // sp on amd can be 32 bit aligned. 909 uintptr_t sp_align_mask = (uintptr_t)(sizeof(int)-1); 910 911 uintptr_t usp = (uintptr_t)fr->sp(); 912 if ((usp & sp_align_mask) != 0) return true; 913 914 uintptr_t ufp = (uintptr_t)fr->fp(); 915 if ((ufp & fp_align_mask) != 0) return true; 916 917 uintptr_t old_sp = (uintptr_t)fr->sender_sp(); 918 if ((old_sp & sp_align_mask) != 0) return true; 919 if (old_sp == 0 || old_sp == (uintptr_t)-1) return true; 920 921 uintptr_t old_fp = (uintptr_t)fr->link(); 922 if ((old_fp & fp_align_mask) != 0) return true; 923 if (old_fp == 0 || old_fp == (uintptr_t)-1 || old_fp == ufp) return true; 924 925 // stack grows downwards; if old_fp is below current fp or if the stack 926 // frame is too large, either the stack is corrupted or fp is not saved 927 // on stack (i.e. on x86, ebp may be used as general register). The stack 928 // is not walkable beyond current frame. 929 if (old_fp < ufp) return true; 930 if (old_fp - ufp > 64 * K) return true; 931 932 return false; 933 } 934 935 #ifdef ASSERT 936 extern "C" void test_random() { 937 const double m = 2147483647; 938 double mean = 0.0, variance = 0.0, t; 939 long reps = 10000; 940 unsigned long seed = 1; 941 942 tty->print_cr("seed %ld for %ld repeats...", seed, reps); 943 os::init_random(seed); 944 long num; 945 for (int k = 0; k < reps; k++) { 946 num = os::random(); 947 double u = (double)num / m; 948 assert(u >= 0.0 && u <= 1.0, "bad random number!"); 949 950 // calculate mean and variance of the random sequence 951 mean += u; 952 variance += (u*u); 953 } 954 mean /= reps; 955 variance /= (reps - 1); 956 957 assert(num == 1043618065, "bad seed"); 958 tty->print_cr("mean of the 1st 10000 numbers: %f", mean); 959 tty->print_cr("variance of the 1st 10000 numbers: %f", variance); 960 const double eps = 0.0001; 961 t = fabsd(mean - 0.5018); 962 assert(t < eps, "bad mean"); 963 t = (variance - 0.3355) < 0.0 ? -(variance - 0.3355) : variance - 0.3355; 964 assert(t < eps, "bad variance"); 965 } 966 #endif 967 968 969 // Set up the boot classpath. 970 971 char* os::format_boot_path(const char* format_string, 972 const char* home, 973 int home_len, 974 char fileSep, 975 char pathSep) { 976 assert((fileSep == '/' && pathSep == ':') || 977 (fileSep == '\\' && pathSep == ';'), "unexpected seperator chars"); 978 979 // Scan the format string to determine the length of the actual 980 // boot classpath, and handle platform dependencies as well. 981 int formatted_path_len = 0; 982 const char* p; 983 for (p = format_string; *p != 0; ++p) { 984 if (*p == '%') formatted_path_len += home_len - 1; 985 ++formatted_path_len; 986 } 987 988 char* formatted_path = NEW_C_HEAP_ARRAY(char, formatted_path_len + 1); 989 if (formatted_path == NULL) { 990 return NULL; 991 } 992 993 // Create boot classpath from format, substituting separator chars and 994 // java home directory. 995 char* q = formatted_path; 996 for (p = format_string; *p != 0; ++p) { 997 switch (*p) { 998 case '%': 999 strcpy(q, home); 1000 q += home_len; 1001 break; 1002 case '/': 1003 *q++ = fileSep; 1004 break; 1005 case ':': 1006 *q++ = pathSep; 1007 break; 1008 default: 1009 *q++ = *p; 1010 } 1011 } 1012 *q = '\0'; 1013 1014 assert((q - formatted_path) == formatted_path_len, "formatted_path size botched"); 1015 return formatted_path; 1016 } 1017 1018 1019 bool os::set_boot_path(char fileSep, char pathSep) { 1020 const char* home = Arguments::get_java_home(); 1021 int home_len = (int)strlen(home); 1022 1023 static const char* meta_index_dir_format = "%/lib/"; 1024 static const char* meta_index_format = "%/lib/meta-index"; 1025 char* meta_index = format_boot_path(meta_index_format, home, home_len, fileSep, pathSep); 1026 if (meta_index == NULL) return false; 1027 char* meta_index_dir = format_boot_path(meta_index_dir_format, home, home_len, fileSep, pathSep); 1028 if (meta_index_dir == NULL) return false; 1029 Arguments::set_meta_index_path(meta_index, meta_index_dir); 1030 1031 // Any modification to the JAR-file list, for the boot classpath must be 1032 // aligned with install/install/make/common/Pack.gmk. Note: boot class 1033 // path class JARs, are stripped for StackMapTable to reduce download size. 1034 static const char classpath_format[] = 1035 "%/lib/resources.jar:" 1036 "%/lib/rt.jar:" 1037 "%/lib/sunrsasign.jar:" 1038 "%/lib/jsse.jar:" 1039 "%/lib/jce.jar:" 1040 "%/lib/charsets.jar:" 1041 1042 // ## TEMPORARY hack to keep the legacy launcher working when 1043 // ## only the boot module is installed (cf. j.l.ClassLoader) 1044 "%/lib/modules/jdk.boot.jar:" 1045 1046 "%/classes"; 1047 char* sysclasspath = format_boot_path(classpath_format, home, home_len, fileSep, pathSep); 1048 if (sysclasspath == NULL) return false; 1049 Arguments::set_sysclasspath(sysclasspath); 1050 1051 return true; 1052 } 1053 1054 /* 1055 * Splits a path, based on its separator, the number of 1056 * elements is returned back in n. 1057 * It is the callers responsibility to: 1058 * a> check the value of n, and n may be 0. 1059 * b> ignore any empty path elements 1060 * c> free up the data. 1061 */ 1062 char** os::split_path(const char* path, int* n) { 1063 *n = 0; 1064 if (path == NULL || strlen(path) == 0) { 1065 return NULL; 1066 } 1067 const char psepchar = *os::path_separator(); 1068 char* inpath = (char*)NEW_C_HEAP_ARRAY(char, strlen(path) + 1); 1069 if (inpath == NULL) { 1070 return NULL; 1071 } 1072 strncpy(inpath, path, strlen(path)); 1073 int count = 1; 1074 char* p = strchr(inpath, psepchar); 1075 // Get a count of elements to allocate memory 1076 while (p != NULL) { 1077 count++; 1078 p++; 1079 p = strchr(p, psepchar); 1080 } 1081 char** opath = (char**) NEW_C_HEAP_ARRAY(char*, count); 1082 if (opath == NULL) { 1083 return NULL; 1084 } 1085 1086 // do the actual splitting 1087 p = inpath; 1088 for (int i = 0 ; i < count ; i++) { 1089 size_t len = strcspn(p, os::path_separator()); 1090 if (len > JVM_MAXPATHLEN) { 1091 return NULL; 1092 } 1093 // allocate the string and add terminator storage 1094 char* s = (char*)NEW_C_HEAP_ARRAY(char, len + 1); 1095 if (s == NULL) { 1096 return NULL; 1097 } 1098 strncpy(s, p, len); 1099 s[len] = '\0'; 1100 opath[i] = s; 1101 p += len + 1; 1102 } 1103 FREE_C_HEAP_ARRAY(char, inpath); 1104 *n = count; 1105 return opath; 1106 } 1107 1108 void os::set_memory_serialize_page(address page) { 1109 int count = log2_intptr(sizeof(class JavaThread)) - log2_intptr(64); 1110 _mem_serialize_page = (volatile int32_t *)page; 1111 // We initialize the serialization page shift count here 1112 // We assume a cache line size of 64 bytes 1113 assert(SerializePageShiftCount == count, 1114 "thread size changed, fix SerializePageShiftCount constant"); 1115 set_serialize_page_mask((uintptr_t)(vm_page_size() - sizeof(int32_t))); 1116 } 1117 1118 static volatile intptr_t SerializePageLock = 0; 1119 1120 // This method is called from signal handler when SIGSEGV occurs while the current 1121 // thread tries to store to the "read-only" memory serialize page during state 1122 // transition. 1123 void os::block_on_serialize_page_trap() { 1124 if (TraceSafepoint) { 1125 tty->print_cr("Block until the serialize page permission restored"); 1126 } 1127 // When VMThread is holding the SerializePageLock during modifying the 1128 // access permission of the memory serialize page, the following call 1129 // will block until the permission of that page is restored to rw. 1130 // Generally, it is unsafe to manipulate locks in signal handlers, but in 1131 // this case, it's OK as the signal is synchronous and we know precisely when 1132 // it can occur. 1133 Thread::muxAcquire(&SerializePageLock, "set_memory_serialize_page"); 1134 Thread::muxRelease(&SerializePageLock); 1135 } 1136 1137 // Serialize all thread state variables 1138 void os::serialize_thread_states() { 1139 // On some platforms such as Solaris & Linux, the time duration of the page 1140 // permission restoration is observed to be much longer than expected due to 1141 // scheduler starvation problem etc. To avoid the long synchronization 1142 // time and expensive page trap spinning, 'SerializePageLock' is used to block 1143 // the mutator thread if such case is encountered. See bug 6546278 for details. 1144 Thread::muxAcquire(&SerializePageLock, "serialize_thread_states"); 1145 os::protect_memory((char *)os::get_memory_serialize_page(), 1146 os::vm_page_size(), MEM_PROT_READ); 1147 os::protect_memory((char *)os::get_memory_serialize_page(), 1148 os::vm_page_size(), MEM_PROT_RW); 1149 Thread::muxRelease(&SerializePageLock); 1150 } 1151 1152 // Returns true if the current stack pointer is above the stack shadow 1153 // pages, false otherwise. 1154 1155 bool os::stack_shadow_pages_available(Thread *thread, methodHandle method) { 1156 assert(StackRedPages > 0 && StackYellowPages > 0,"Sanity check"); 1157 address sp = current_stack_pointer(); 1158 // Check if we have StackShadowPages above the yellow zone. This parameter 1159 // is dependent on the depth of the maximum VM call stack possible from 1160 // the handler for stack overflow. 'instanceof' in the stack overflow 1161 // handler or a println uses at least 8k stack of VM and native code 1162 // respectively. 1163 const int framesize_in_bytes = 1164 Interpreter::size_top_interpreter_activation(method()) * wordSize; 1165 int reserved_area = ((StackShadowPages + StackRedPages + StackYellowPages) 1166 * vm_page_size()) + framesize_in_bytes; 1167 // The very lower end of the stack 1168 address stack_limit = thread->stack_base() - thread->stack_size(); 1169 return (sp > (stack_limit + reserved_area)); 1170 } 1171 1172 size_t os::page_size_for_region(size_t region_min_size, size_t region_max_size, 1173 uint min_pages) 1174 { 1175 assert(min_pages > 0, "sanity"); 1176 if (UseLargePages) { 1177 const size_t max_page_size = region_max_size / min_pages; 1178 1179 for (unsigned int i = 0; _page_sizes[i] != 0; ++i) { 1180 const size_t sz = _page_sizes[i]; 1181 const size_t mask = sz - 1; 1182 if ((region_min_size & mask) == 0 && (region_max_size & mask) == 0) { 1183 // The largest page size with no fragmentation. 1184 return sz; 1185 } 1186 1187 if (sz <= max_page_size) { 1188 // The largest page size that satisfies the min_pages requirement. 1189 return sz; 1190 } 1191 } 1192 } 1193 1194 return vm_page_size(); 1195 } 1196 1197 #ifndef PRODUCT 1198 void os::trace_page_sizes(const char* str, const size_t region_min_size, 1199 const size_t region_max_size, const size_t page_size, 1200 const char* base, const size_t size) 1201 { 1202 if (TracePageSizes) { 1203 tty->print_cr("%s: min=" SIZE_FORMAT " max=" SIZE_FORMAT 1204 " pg_sz=" SIZE_FORMAT " base=" PTR_FORMAT 1205 " size=" SIZE_FORMAT, 1206 str, region_min_size, region_max_size, 1207 page_size, base, size); 1208 } 1209 } 1210 #endif // #ifndef PRODUCT 1211 1212 // This is the working definition of a server class machine: 1213 // >= 2 physical CPU's and >=2GB of memory, with some fuzz 1214 // because the graphics memory (?) sometimes masks physical memory. 1215 // If you want to change the definition of a server class machine 1216 // on some OS or platform, e.g., >=4GB on Windohs platforms, 1217 // then you'll have to parameterize this method based on that state, 1218 // as was done for logical processors here, or replicate and 1219 // specialize this method for each platform. (Or fix os to have 1220 // some inheritance structure and use subclassing. Sigh.) 1221 // If you want some platform to always or never behave as a server 1222 // class machine, change the setting of AlwaysActAsServerClassMachine 1223 // and NeverActAsServerClassMachine in globals*.hpp. 1224 bool os::is_server_class_machine() { 1225 // First check for the early returns 1226 if (NeverActAsServerClassMachine) { 1227 return false; 1228 } 1229 if (AlwaysActAsServerClassMachine) { 1230 return true; 1231 } 1232 // Then actually look at the machine 1233 bool result = false; 1234 const unsigned int server_processors = 2; 1235 const julong server_memory = 2UL * G; 1236 // We seem not to get our full complement of memory. 1237 // We allow some part (1/8?) of the memory to be "missing", 1238 // based on the sizes of DIMMs, and maybe graphics cards. 1239 const julong missing_memory = 256UL * M; 1240 1241 /* Is this a server class machine? */ 1242 if ((os::active_processor_count() >= (int)server_processors) && 1243 (os::physical_memory() >= (server_memory - missing_memory))) { 1244 const unsigned int logical_processors = 1245 VM_Version::logical_processors_per_package(); 1246 if (logical_processors > 1) { 1247 const unsigned int physical_packages = 1248 os::active_processor_count() / logical_processors; 1249 if (physical_packages > server_processors) { 1250 result = true; 1251 } 1252 } else { 1253 result = true; 1254 } 1255 } 1256 return result; 1257 }