os.cpp revision 548:773234c55e8c
1/* 2 * Copyright 1997-2008 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, 20 * CA 95054 USA or visit www.sun.com if you need additional information or 21 * have any questions. 22 * 23 */ 24 25# include "incls/_precompiled.incl" 26# include "incls/_os.cpp.incl" 27 28# include <signal.h> 29 30OSThread* os::_starting_thread = NULL; 31address os::_polling_page = NULL; 32volatile int32_t* os::_mem_serialize_page = NULL; 33uintptr_t os::_serialize_page_mask = 0; 34long os::_rand_seed = 1; 35int os::_processor_count = 0; 36size_t os::_page_sizes[os::page_sizes_max]; 37 38#ifndef PRODUCT 39int os::num_mallocs = 0; // # of calls to malloc/realloc 40size_t os::alloc_bytes = 0; // # of bytes allocated 41int 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. 52char* 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 132OSReturn 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 153OSReturn 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 176static 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 VMThread::execute(&op1); 212 } 213 if (JvmtiExport::should_post_data_dump()) { 214 JvmtiExport::post_data_dump(); 215 } 216 break; 217 } 218 default: { 219 // Dispatch the signal to java 220 HandleMark hm(THREAD); 221 klassOop k = SystemDictionary::resolve_or_null(vmSymbolHandles::sun_misc_Signal(), THREAD); 222 KlassHandle klass (THREAD, k); 223 if (klass.not_null()) { 224 JavaValue result(T_VOID); 225 JavaCallArguments args; 226 args.push_int(sig); 227 JavaCalls::call_static( 228 &result, 229 klass, 230 vmSymbolHandles::dispatch_name(), 231 vmSymbolHandles::int_void_signature(), 232 &args, 233 THREAD 234 ); 235 } 236 if (HAS_PENDING_EXCEPTION) { 237 // tty is initialized early so we don't expect it to be null, but 238 // if it is we can't risk doing an initialization that might 239 // trigger additional out-of-memory conditions 240 if (tty != NULL) { 241 char klass_name[256]; 242 char tmp_sig_name[16]; 243 const char* sig_name = "UNKNOWN"; 244 instanceKlass::cast(PENDING_EXCEPTION->klass())-> 245 name()->as_klass_external_name(klass_name, 256); 246 if (os::exception_name(sig, tmp_sig_name, 16) != NULL) 247 sig_name = tmp_sig_name; 248 warning("Exception %s occurred dispatching signal %s to handler" 249 "- the VM may need to be forcibly terminated", 250 klass_name, sig_name ); 251 } 252 CLEAR_PENDING_EXCEPTION; 253 } 254 } 255 } 256 } 257} 258 259 260void os::signal_init() { 261 if (!ReduceSignalUsage) { 262 // Setup JavaThread for processing signals 263 EXCEPTION_MARK; 264 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK); 265 instanceKlassHandle klass (THREAD, k); 266 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 267 268 const char thread_name[] = "Signal Dispatcher"; 269 Handle string = java_lang_String::create_from_str(thread_name, CHECK); 270 271 // Initialize thread_oop to put it into the system threadGroup 272 Handle thread_group (THREAD, Universe::system_thread_group()); 273 JavaValue result(T_VOID); 274 JavaCalls::call_special(&result, thread_oop, 275 klass, 276 vmSymbolHandles::object_initializer_name(), 277 vmSymbolHandles::threadgroup_string_void_signature(), 278 thread_group, 279 string, 280 CHECK); 281 282 KlassHandle group(THREAD, SystemDictionary::threadGroup_klass()); 283 JavaCalls::call_special(&result, 284 thread_group, 285 group, 286 vmSymbolHandles::add_method_name(), 287 vmSymbolHandles::thread_void_signature(), 288 thread_oop, // ARG 1 289 CHECK); 290 291 os::signal_init_pd(); 292 293 { MutexLocker mu(Threads_lock); 294 JavaThread* signal_thread = new JavaThread(&signal_thread_entry); 295 296 // At this point it may be possible that no osthread was created for the 297 // JavaThread due to lack of memory. We would have to throw an exception 298 // in that case. However, since this must work and we do not allow 299 // exceptions anyway, check and abort if this fails. 300 if (signal_thread == NULL || signal_thread->osthread() == NULL) { 301 vm_exit_during_initialization("java.lang.OutOfMemoryError", 302 "unable to create new native thread"); 303 } 304 305 java_lang_Thread::set_thread(thread_oop(), signal_thread); 306 java_lang_Thread::set_priority(thread_oop(), NearMaxPriority); 307 java_lang_Thread::set_daemon(thread_oop()); 308 309 signal_thread->set_threadObj(thread_oop()); 310 Threads::add(signal_thread); 311 Thread::start(signal_thread); 312 } 313 // Handle ^BREAK 314 os::signal(SIGBREAK, os::user_handler()); 315 } 316} 317 318 319void os::terminate_signal_thread() { 320 if (!ReduceSignalUsage) 321 signal_notify(sigexitnum_pd()); 322} 323 324 325// --------------------- loading libraries --------------------- 326 327typedef jint (JNICALL *JNI_OnLoad_t)(JavaVM *, void *); 328extern struct JavaVM_ main_vm; 329 330static void* _native_java_library = NULL; 331 332void* os::native_java_library() { 333 if (_native_java_library == NULL) { 334 char buffer[JVM_MAXPATHLEN]; 335 char ebuf[1024]; 336 337 // Try to load verify dll first. In 1.3 java dll depends on it and is not 338 // always able to find it when the loading executable is outside the JDK. 339 // In order to keep working with 1.2 we ignore any loading errors. 340 dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), "verify"); 341 dll_load(buffer, ebuf, sizeof(ebuf)); 342 343 // Load java dll 344 dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), "java"); 345 _native_java_library = dll_load(buffer, ebuf, sizeof(ebuf)); 346 if (_native_java_library == NULL) { 347 vm_exit_during_initialization("Unable to load native library", ebuf); 348 } 349 } 350 static jboolean onLoaded = JNI_FALSE; 351 if (onLoaded) { 352 // We may have to wait to fire OnLoad until TLS is initialized. 353 if (ThreadLocalStorage::is_initialized()) { 354 // The JNI_OnLoad handling is normally done by method load in 355 // java.lang.ClassLoader$NativeLibrary, but the VM loads the base library 356 // explicitly so we have to check for JNI_OnLoad as well 357 const char *onLoadSymbols[] = JNI_ONLOAD_SYMBOLS; 358 JNI_OnLoad_t JNI_OnLoad = CAST_TO_FN_PTR( 359 JNI_OnLoad_t, dll_lookup(_native_java_library, onLoadSymbols[0])); 360 if (JNI_OnLoad != NULL) { 361 JavaThread* thread = JavaThread::current(); 362 ThreadToNativeFromVM ttn(thread); 363 HandleMark hm(thread); 364 jint ver = (*JNI_OnLoad)(&main_vm, NULL); 365 onLoaded = JNI_TRUE; 366 if (!Threads::is_supported_jni_version_including_1_1(ver)) { 367 vm_exit_during_initialization("Unsupported JNI version"); 368 } 369 } 370 } 371 } 372 return _native_java_library; 373} 374 375// --------------------- heap allocation utilities --------------------- 376 377char *os::strdup(const char *str) { 378 size_t size = strlen(str); 379 char *dup_str = (char *)malloc(size + 1); 380 if (dup_str == NULL) return NULL; 381 strcpy(dup_str, str); 382 return dup_str; 383} 384 385 386 387#ifdef ASSERT 388#define space_before (MallocCushion + sizeof(double)) 389#define space_after MallocCushion 390#define size_addr_from_base(p) (size_t*)(p + space_before - sizeof(size_t)) 391#define size_addr_from_obj(p) ((size_t*)p - 1) 392// MallocCushion: size of extra cushion allocated around objects with +UseMallocOnly 393// NB: cannot be debug variable, because these aren't set from the command line until 394// *after* the first few allocs already happened 395#define MallocCushion 16 396#else 397#define space_before 0 398#define space_after 0 399#define size_addr_from_base(p) should not use w/o ASSERT 400#define size_addr_from_obj(p) should not use w/o ASSERT 401#define MallocCushion 0 402#endif 403#define paranoid 0 /* only set to 1 if you suspect checking code has bug */ 404 405#ifdef ASSERT 406inline size_t get_size(void* obj) { 407 size_t size = *size_addr_from_obj(obj); 408 if (size < 0 ) 409 fatal2("free: size field of object #%p was overwritten (%lu)", obj, size); 410 return size; 411} 412 413u_char* find_cushion_backwards(u_char* start) { 414 u_char* p = start; 415 while (p[ 0] != badResourceValue || p[-1] != badResourceValue || 416 p[-2] != badResourceValue || p[-3] != badResourceValue) p--; 417 // ok, we have four consecutive marker bytes; find start 418 u_char* q = p - 4; 419 while (*q == badResourceValue) q--; 420 return q + 1; 421} 422 423u_char* find_cushion_forwards(u_char* start) { 424 u_char* p = start; 425 while (p[0] != badResourceValue || p[1] != badResourceValue || 426 p[2] != badResourceValue || p[3] != badResourceValue) p++; 427 // ok, we have four consecutive marker bytes; find end of cushion 428 u_char* q = p + 4; 429 while (*q == badResourceValue) q++; 430 return q - MallocCushion; 431} 432 433void print_neighbor_blocks(void* ptr) { 434 // find block allocated before ptr (not entirely crash-proof) 435 if (MallocCushion < 4) { 436 tty->print_cr("### cannot find previous block (MallocCushion < 4)"); 437 return; 438 } 439 u_char* start_of_this_block = (u_char*)ptr - space_before; 440 u_char* end_of_prev_block_data = start_of_this_block - space_after -1; 441 // look for cushion in front of prev. block 442 u_char* start_of_prev_block = find_cushion_backwards(end_of_prev_block_data); 443 ptrdiff_t size = *size_addr_from_base(start_of_prev_block); 444 u_char* obj = start_of_prev_block + space_before; 445 if (size <= 0 ) { 446 // start is bad; mayhave been confused by OS data inbetween objects 447 // search one more backwards 448 start_of_prev_block = find_cushion_backwards(start_of_prev_block); 449 size = *size_addr_from_base(start_of_prev_block); 450 obj = start_of_prev_block + space_before; 451 } 452 453 if (start_of_prev_block + space_before + size + space_after == start_of_this_block) { 454 tty->print_cr("### previous object: %p (%ld bytes)", obj, size); 455 } else { 456 tty->print_cr("### previous object (not sure if correct): %p (%ld bytes)", obj, size); 457 } 458 459 // now find successor block 460 u_char* start_of_next_block = (u_char*)ptr + *size_addr_from_obj(ptr) + space_after; 461 start_of_next_block = find_cushion_forwards(start_of_next_block); 462 u_char* next_obj = start_of_next_block + space_before; 463 ptrdiff_t next_size = *size_addr_from_base(start_of_next_block); 464 if (start_of_next_block[0] == badResourceValue && 465 start_of_next_block[1] == badResourceValue && 466 start_of_next_block[2] == badResourceValue && 467 start_of_next_block[3] == badResourceValue) { 468 tty->print_cr("### next object: %p (%ld bytes)", next_obj, next_size); 469 } else { 470 tty->print_cr("### next object (not sure if correct): %p (%ld bytes)", next_obj, next_size); 471 } 472} 473 474 475void report_heap_error(void* memblock, void* bad, const char* where) { 476 tty->print_cr("## nof_mallocs = %d, nof_frees = %d", os::num_mallocs, os::num_frees); 477 tty->print_cr("## memory stomp: byte at %p %s object %p", bad, where, memblock); 478 print_neighbor_blocks(memblock); 479 fatal("memory stomping error"); 480} 481 482void verify_block(void* memblock) { 483 size_t size = get_size(memblock); 484 if (MallocCushion) { 485 u_char* ptr = (u_char*)memblock - space_before; 486 for (int i = 0; i < MallocCushion; i++) { 487 if (ptr[i] != badResourceValue) { 488 report_heap_error(memblock, ptr+i, "in front of"); 489 } 490 } 491 u_char* end = (u_char*)memblock + size + space_after; 492 for (int j = -MallocCushion; j < 0; j++) { 493 if (end[j] != badResourceValue) { 494 report_heap_error(memblock, end+j, "after"); 495 } 496 } 497 } 498} 499#endif 500 501void* os::malloc(size_t size) { 502 NOT_PRODUCT(num_mallocs++); 503 NOT_PRODUCT(alloc_bytes += size); 504 505 if (size == 0) { 506 // return a valid pointer if size is zero 507 // if NULL is returned the calling functions assume out of memory. 508 size = 1; 509 } 510 511 NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap()); 512 u_char* ptr = (u_char*)::malloc(size + space_before + space_after); 513#ifdef ASSERT 514 if (ptr == NULL) return NULL; 515 if (MallocCushion) { 516 for (u_char* p = ptr; p < ptr + MallocCushion; p++) *p = (u_char)badResourceValue; 517 u_char* end = ptr + space_before + size; 518 for (u_char* pq = ptr+MallocCushion; pq < end; pq++) *pq = (u_char)uninitBlockPad; 519 for (u_char* q = end; q < end + MallocCushion; q++) *q = (u_char)badResourceValue; 520 } 521 // put size just before data 522 *size_addr_from_base(ptr) = size; 523#endif 524 u_char* memblock = ptr + space_before; 525 if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) { 526 tty->print_cr("os::malloc caught, %lu bytes --> %p", size, memblock); 527 breakpoint(); 528 } 529 debug_only(if (paranoid) verify_block(memblock)); 530 if (PrintMalloc && tty != NULL) tty->print_cr("os::malloc %lu bytes --> %p", size, memblock); 531 return memblock; 532} 533 534 535void* os::realloc(void *memblock, size_t size) { 536 NOT_PRODUCT(num_mallocs++); 537 NOT_PRODUCT(alloc_bytes += size); 538#ifndef ASSERT 539 return ::realloc(memblock, size); 540#else 541 if (memblock == NULL) { 542 return os::malloc(size); 543 } 544 if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) { 545 tty->print_cr("os::realloc caught %p", memblock); 546 breakpoint(); 547 } 548 verify_block(memblock); 549 NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap()); 550 if (size == 0) return NULL; 551 // always move the block 552 void* ptr = malloc(size); 553 if (PrintMalloc) tty->print_cr("os::remalloc %lu bytes, %p --> %p", size, memblock, ptr); 554 // Copy to new memory if malloc didn't fail 555 if ( ptr != NULL ) { 556 memcpy(ptr, memblock, MIN2(size, get_size(memblock))); 557 if (paranoid) verify_block(ptr); 558 if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) { 559 tty->print_cr("os::realloc caught, %lu bytes --> %p", size, ptr); 560 breakpoint(); 561 } 562 free(memblock); 563 } 564 return ptr; 565#endif 566} 567 568 569void os::free(void *memblock) { 570 NOT_PRODUCT(num_frees++); 571#ifdef ASSERT 572 if (memblock == NULL) return; 573 if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) { 574 if (tty != NULL) tty->print_cr("os::free caught %p", memblock); 575 breakpoint(); 576 } 577 verify_block(memblock); 578 if (PrintMalloc && tty != NULL) 579 // tty->print_cr("os::free %p", memblock); 580 fprintf(stderr, "os::free %p\n", memblock); 581 NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap()); 582 // Added by detlefs. 583 if (MallocCushion) { 584 u_char* ptr = (u_char*)memblock - space_before; 585 for (u_char* p = ptr; p < ptr + MallocCushion; p++) { 586 guarantee(*p == badResourceValue, 587 "Thing freed should be malloc result."); 588 *p = (u_char)freeBlockPad; 589 } 590 size_t size = get_size(memblock); 591 u_char* end = ptr + space_before + size; 592 for (u_char* q = end; q < end + MallocCushion; q++) { 593 guarantee(*q == badResourceValue, 594 "Thing freed should be malloc result."); 595 *q = (u_char)freeBlockPad; 596 } 597 } 598#endif 599 ::free((char*)memblock - space_before); 600} 601 602void os::init_random(long initval) { 603 _rand_seed = initval; 604} 605 606 607long os::random() { 608 /* standard, well-known linear congruential random generator with 609 * next_rand = (16807*seed) mod (2**31-1) 610 * see 611 * (1) "Random Number Generators: Good Ones Are Hard to Find", 612 * S.K. Park and K.W. Miller, Communications of the ACM 31:10 (Oct 1988), 613 * (2) "Two Fast Implementations of the 'Minimal Standard' Random 614 * Number Generator", David G. Carta, Comm. ACM 33, 1 (Jan 1990), pp. 87-88. 615 */ 616 const long a = 16807; 617 const unsigned long m = 2147483647; 618 const long q = m / a; assert(q == 127773, "weird math"); 619 const long r = m % a; assert(r == 2836, "weird math"); 620 621 // compute az=2^31p+q 622 unsigned long lo = a * (long)(_rand_seed & 0xFFFF); 623 unsigned long hi = a * (long)((unsigned long)_rand_seed >> 16); 624 lo += (hi & 0x7FFF) << 16; 625 626 // if q overflowed, ignore the overflow and increment q 627 if (lo > m) { 628 lo &= m; 629 ++lo; 630 } 631 lo += hi >> 15; 632 633 // if (p+q) overflowed, ignore the overflow and increment (p+q) 634 if (lo > m) { 635 lo &= m; 636 ++lo; 637 } 638 return (_rand_seed = lo); 639} 640 641// The INITIALIZED state is distinguished from the SUSPENDED state because the 642// conditions in which a thread is first started are different from those in which 643// a suspension is resumed. These differences make it hard for us to apply the 644// tougher checks when starting threads that we want to do when resuming them. 645// However, when start_thread is called as a result of Thread.start, on a Java 646// thread, the operation is synchronized on the Java Thread object. So there 647// cannot be a race to start the thread and hence for the thread to exit while 648// we are working on it. Non-Java threads that start Java threads either have 649// to do so in a context in which races are impossible, or should do appropriate 650// locking. 651 652void os::start_thread(Thread* thread) { 653 // guard suspend/resume 654 MutexLockerEx ml(thread->SR_lock(), Mutex::_no_safepoint_check_flag); 655 OSThread* osthread = thread->osthread(); 656 osthread->set_state(RUNNABLE); 657 pd_start_thread(thread); 658} 659 660//--------------------------------------------------------------------------- 661// Helper functions for fatal error handler 662 663void os::print_hex_dump(outputStream* st, address start, address end, int unitsize) { 664 assert(unitsize == 1 || unitsize == 2 || unitsize == 4 || unitsize == 8, "just checking"); 665 666 int cols = 0; 667 int cols_per_line = 0; 668 switch (unitsize) { 669 case 1: cols_per_line = 16; break; 670 case 2: cols_per_line = 8; break; 671 case 4: cols_per_line = 4; break; 672 case 8: cols_per_line = 2; break; 673 default: return; 674 } 675 676 address p = start; 677 st->print(PTR_FORMAT ": ", start); 678 while (p < end) { 679 switch (unitsize) { 680 case 1: st->print("%02x", *(u1*)p); break; 681 case 2: st->print("%04x", *(u2*)p); break; 682 case 4: st->print("%08x", *(u4*)p); break; 683 case 8: st->print("%016" FORMAT64_MODIFIER "x", *(u8*)p); break; 684 } 685 p += unitsize; 686 cols++; 687 if (cols >= cols_per_line && p < end) { 688 cols = 0; 689 st->cr(); 690 st->print(PTR_FORMAT ": ", p); 691 } else { 692 st->print(" "); 693 } 694 } 695 st->cr(); 696} 697 698void os::print_environment_variables(outputStream* st, const char** env_list, 699 char* buffer, int len) { 700 if (env_list) { 701 st->print_cr("Environment Variables:"); 702 703 for (int i = 0; env_list[i] != NULL; i++) { 704 if (getenv(env_list[i], buffer, len)) { 705 st->print(env_list[i]); 706 st->print("="); 707 st->print_cr(buffer); 708 } 709 } 710 } 711} 712 713void os::print_cpu_info(outputStream* st) { 714 // cpu 715 st->print("CPU:"); 716 st->print("total %d", os::processor_count()); 717 // It's not safe to query number of active processors after crash 718 // st->print("(active %d)", os::active_processor_count()); 719 st->print(" %s", VM_Version::cpu_features()); 720 st->cr(); 721} 722 723void os::print_date_and_time(outputStream *st) { 724 time_t tloc; 725 (void)time(&tloc); 726 st->print("time: %s", ctime(&tloc)); // ctime adds newline. 727 728 double t = os::elapsedTime(); 729 // NOTE: It tends to crash after a SEGV if we want to printf("%f",...) in 730 // Linux. Must be a bug in glibc ? Workaround is to round "t" to int 731 // before printf. We lost some precision, but who cares? 732 st->print_cr("elapsed time: %d seconds", (int)t); 733} 734 735 736// Looks like all platforms except IA64 can use the same function to check 737// if C stack is walkable beyond current frame. The check for fp() is not 738// necessary on Sparc, but it's harmless. 739bool os::is_first_C_frame(frame* fr) { 740#ifdef IA64 741 // In order to walk native frames on Itanium, we need to access the unwind 742 // table, which is inside ELF. We don't want to parse ELF after fatal error, 743 // so return true for IA64. If we need to support C stack walking on IA64, 744 // this function needs to be moved to CPU specific files, as fp() on IA64 745 // is register stack, which grows towards higher memory address. 746 return true; 747#endif 748 749 // Load up sp, fp, sender sp and sender fp, check for reasonable values. 750 // Check usp first, because if that's bad the other accessors may fault 751 // on some architectures. Ditto ufp second, etc. 752 uintptr_t fp_align_mask = (uintptr_t)(sizeof(address)-1); 753 // sp on amd can be 32 bit aligned. 754 uintptr_t sp_align_mask = (uintptr_t)(sizeof(int)-1); 755 756 uintptr_t usp = (uintptr_t)fr->sp(); 757 if ((usp & sp_align_mask) != 0) return true; 758 759 uintptr_t ufp = (uintptr_t)fr->fp(); 760 if ((ufp & fp_align_mask) != 0) return true; 761 762 uintptr_t old_sp = (uintptr_t)fr->sender_sp(); 763 if ((old_sp & sp_align_mask) != 0) return true; 764 if (old_sp == 0 || old_sp == (uintptr_t)-1) return true; 765 766 uintptr_t old_fp = (uintptr_t)fr->link(); 767 if ((old_fp & fp_align_mask) != 0) return true; 768 if (old_fp == 0 || old_fp == (uintptr_t)-1 || old_fp == ufp) return true; 769 770 // stack grows downwards; if old_fp is below current fp or if the stack 771 // frame is too large, either the stack is corrupted or fp is not saved 772 // on stack (i.e. on x86, ebp may be used as general register). The stack 773 // is not walkable beyond current frame. 774 if (old_fp < ufp) return true; 775 if (old_fp - ufp > 64 * K) return true; 776 777 return false; 778} 779 780#ifdef ASSERT 781extern "C" void test_random() { 782 const double m = 2147483647; 783 double mean = 0.0, variance = 0.0, t; 784 long reps = 10000; 785 unsigned long seed = 1; 786 787 tty->print_cr("seed %ld for %ld repeats...", seed, reps); 788 os::init_random(seed); 789 long num; 790 for (int k = 0; k < reps; k++) { 791 num = os::random(); 792 double u = (double)num / m; 793 assert(u >= 0.0 && u <= 1.0, "bad random number!"); 794 795 // calculate mean and variance of the random sequence 796 mean += u; 797 variance += (u*u); 798 } 799 mean /= reps; 800 variance /= (reps - 1); 801 802 assert(num == 1043618065, "bad seed"); 803 tty->print_cr("mean of the 1st 10000 numbers: %f", mean); 804 tty->print_cr("variance of the 1st 10000 numbers: %f", variance); 805 const double eps = 0.0001; 806 t = fabsd(mean - 0.5018); 807 assert(t < eps, "bad mean"); 808 t = (variance - 0.3355) < 0.0 ? -(variance - 0.3355) : variance - 0.3355; 809 assert(t < eps, "bad variance"); 810} 811#endif 812 813 814// Set up the boot classpath. 815 816char* os::format_boot_path(const char* format_string, 817 const char* home, 818 int home_len, 819 char fileSep, 820 char pathSep) { 821 assert((fileSep == '/' && pathSep == ':') || 822 (fileSep == '\\' && pathSep == ';'), "unexpected seperator chars"); 823 824 // Scan the format string to determine the length of the actual 825 // boot classpath, and handle platform dependencies as well. 826 int formatted_path_len = 0; 827 const char* p; 828 for (p = format_string; *p != 0; ++p) { 829 if (*p == '%') formatted_path_len += home_len - 1; 830 ++formatted_path_len; 831 } 832 833 char* formatted_path = NEW_C_HEAP_ARRAY(char, formatted_path_len + 1); 834 if (formatted_path == NULL) { 835 return NULL; 836 } 837 838 // Create boot classpath from format, substituting separator chars and 839 // java home directory. 840 char* q = formatted_path; 841 for (p = format_string; *p != 0; ++p) { 842 switch (*p) { 843 case '%': 844 strcpy(q, home); 845 q += home_len; 846 break; 847 case '/': 848 *q++ = fileSep; 849 break; 850 case ':': 851 *q++ = pathSep; 852 break; 853 default: 854 *q++ = *p; 855 } 856 } 857 *q = '\0'; 858 859 assert((q - formatted_path) == formatted_path_len, "formatted_path size botched"); 860 return formatted_path; 861} 862 863 864bool os::set_boot_path(char fileSep, char pathSep) { 865 866 const char* home = Arguments::get_java_home(); 867 int home_len = (int)strlen(home); 868 869 static const char* meta_index_dir_format = "%/lib/"; 870 static const char* meta_index_format = "%/lib/meta-index"; 871 char* meta_index = format_boot_path(meta_index_format, home, home_len, fileSep, pathSep); 872 if (meta_index == NULL) return false; 873 char* meta_index_dir = format_boot_path(meta_index_dir_format, home, home_len, fileSep, pathSep); 874 if (meta_index_dir == NULL) return false; 875 Arguments::set_meta_index_path(meta_index, meta_index_dir); 876 877 // Any modification to the JAR-file list, for the boot classpath must be 878 // aligned with install/install/make/common/Pack.gmk. Note: boot class 879 // path class JARs, are stripped for StackMapTable to reduce download size. 880 static const char classpath_format[] = 881 "%/lib/resources.jar:" 882 "%/lib/rt.jar:" 883 "%/lib/sunrsasign.jar:" 884 "%/lib/jsse.jar:" 885 "%/lib/jce.jar:" 886 "%/lib/charsets.jar:" 887 "%/classes"; 888 char* sysclasspath = format_boot_path(classpath_format, home, home_len, fileSep, pathSep); 889 if (sysclasspath == NULL) return false; 890 Arguments::set_sysclasspath(sysclasspath); 891 892 return true; 893} 894 895void os::set_memory_serialize_page(address page) { 896 int count = log2_intptr(sizeof(class JavaThread)) - log2_intptr(64); 897 _mem_serialize_page = (volatile int32_t *)page; 898 // We initialize the serialization page shift count here 899 // We assume a cache line size of 64 bytes 900 assert(SerializePageShiftCount == count, 901 "thread size changed, fix SerializePageShiftCount constant"); 902 set_serialize_page_mask((uintptr_t)(vm_page_size() - sizeof(int32_t))); 903} 904 905static volatile intptr_t SerializePageLock = 0; 906 907// This method is called from signal handler when SIGSEGV occurs while the current 908// thread tries to store to the "read-only" memory serialize page during state 909// transition. 910void os::block_on_serialize_page_trap() { 911 if (TraceSafepoint) { 912 tty->print_cr("Block until the serialize page permission restored"); 913 } 914 // When VMThread is holding the SerializePageLock during modifying the 915 // access permission of the memory serialize page, the following call 916 // will block until the permission of that page is restored to rw. 917 // Generally, it is unsafe to manipulate locks in signal handlers, but in 918 // this case, it's OK as the signal is synchronous and we know precisely when 919 // it can occur. 920 Thread::muxAcquire(&SerializePageLock, "set_memory_serialize_page"); 921 Thread::muxRelease(&SerializePageLock); 922} 923 924// Serialize all thread state variables 925void os::serialize_thread_states() { 926 // On some platforms such as Solaris & Linux, the time duration of the page 927 // permission restoration is observed to be much longer than expected due to 928 // scheduler starvation problem etc. To avoid the long synchronization 929 // time and expensive page trap spinning, 'SerializePageLock' is used to block 930 // the mutator thread if such case is encountered. See bug 6546278 for details. 931 Thread::muxAcquire(&SerializePageLock, "serialize_thread_states"); 932 os::protect_memory((char *)os::get_memory_serialize_page(), 933 os::vm_page_size(), MEM_PROT_READ); 934 os::protect_memory((char *)os::get_memory_serialize_page(), 935 os::vm_page_size(), MEM_PROT_RW); 936 Thread::muxRelease(&SerializePageLock); 937} 938 939// Returns true if the current stack pointer is above the stack shadow 940// pages, false otherwise. 941 942bool os::stack_shadow_pages_available(Thread *thread, methodHandle method) { 943 assert(StackRedPages > 0 && StackYellowPages > 0,"Sanity check"); 944 address sp = current_stack_pointer(); 945 // Check if we have StackShadowPages above the yellow zone. This parameter 946 // is dependant on the depth of the maximum VM call stack possible from 947 // the handler for stack overflow. 'instanceof' in the stack overflow 948 // handler or a println uses at least 8k stack of VM and native code 949 // respectively. 950 const int framesize_in_bytes = 951 Interpreter::size_top_interpreter_activation(method()) * wordSize; 952 int reserved_area = ((StackShadowPages + StackRedPages + StackYellowPages) 953 * vm_page_size()) + framesize_in_bytes; 954 // The very lower end of the stack 955 address stack_limit = thread->stack_base() - thread->stack_size(); 956 return (sp > (stack_limit + reserved_area)); 957} 958 959size_t os::page_size_for_region(size_t region_min_size, size_t region_max_size, 960 uint min_pages) 961{ 962 assert(min_pages > 0, "sanity"); 963 if (UseLargePages) { 964 const size_t max_page_size = region_max_size / min_pages; 965 966 for (unsigned int i = 0; _page_sizes[i] != 0; ++i) { 967 const size_t sz = _page_sizes[i]; 968 const size_t mask = sz - 1; 969 if ((region_min_size & mask) == 0 && (region_max_size & mask) == 0) { 970 // The largest page size with no fragmentation. 971 return sz; 972 } 973 974 if (sz <= max_page_size) { 975 // The largest page size that satisfies the min_pages requirement. 976 return sz; 977 } 978 } 979 } 980 981 return vm_page_size(); 982} 983 984#ifndef PRODUCT 985void os::trace_page_sizes(const char* str, const size_t region_min_size, 986 const size_t region_max_size, const size_t page_size, 987 const char* base, const size_t size) 988{ 989 if (TracePageSizes) { 990 tty->print_cr("%s: min=" SIZE_FORMAT " max=" SIZE_FORMAT 991 " pg_sz=" SIZE_FORMAT " base=" PTR_FORMAT 992 " size=" SIZE_FORMAT, 993 str, region_min_size, region_max_size, 994 page_size, base, size); 995 } 996} 997#endif // #ifndef PRODUCT 998 999// This is the working definition of a server class machine: 1000// >= 2 physical CPU's and >=2GB of memory, with some fuzz 1001// because the graphics memory (?) sometimes masks physical memory. 1002// If you want to change the definition of a server class machine 1003// on some OS or platform, e.g., >=4GB on Windohs platforms, 1004// then you'll have to parameterize this method based on that state, 1005// as was done for logical processors here, or replicate and 1006// specialize this method for each platform. (Or fix os to have 1007// some inheritance structure and use subclassing. Sigh.) 1008// If you want some platform to always or never behave as a server 1009// class machine, change the setting of AlwaysActAsServerClassMachine 1010// and NeverActAsServerClassMachine in globals*.hpp. 1011bool os::is_server_class_machine() { 1012 // First check for the early returns 1013 if (NeverActAsServerClassMachine) { 1014 return false; 1015 } 1016 if (AlwaysActAsServerClassMachine) { 1017 return true; 1018 } 1019 // Then actually look at the machine 1020 bool result = false; 1021 const unsigned int server_processors = 2; 1022 const julong server_memory = 2UL * G; 1023 // We seem not to get our full complement of memory. 1024 // We allow some part (1/8?) of the memory to be "missing", 1025 // based on the sizes of DIMMs, and maybe graphics cards. 1026 const julong missing_memory = 256UL * M; 1027 1028 /* Is this a server class machine? */ 1029 if ((os::active_processor_count() >= (int)server_processors) && 1030 (os::physical_memory() >= (server_memory - missing_memory))) { 1031 const unsigned int logical_processors = 1032 VM_Version::logical_processors_per_package(); 1033 if (logical_processors > 1) { 1034 const unsigned int physical_packages = 1035 os::active_processor_count() / logical_processors; 1036 if (physical_packages > server_processors) { 1037 result = true; 1038 } 1039 } else { 1040 result = true; 1041 } 1042 } 1043 return result; 1044} 1045