Fri, 27 Feb 2009 13:27:09 -0800
6810672: Comment typos
Summary: I have collected some typos I have found while looking at the code.
Reviewed-by: kvn, never
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 */
25 # include "incls/_precompiled.incl"
26 # include "incls/_os.cpp.incl"
28 # include <signal.h>
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];
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
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;
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;
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);
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 }
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
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 }
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;
159 for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] > os_prio; p--) ;
160 priority = (ThreadPriority)p;
161 return OS_OK;
162 }
165 // --------------------- sun.misc.Signal (optional) ---------------------
168 // SIGBREAK is sent by the keyboard to query the VM state
169 #ifndef SIGBREAK
170 #define SIGBREAK SIGQUIT
171 #endif
173 // sigexitnum_pd is a platform-specific special signal used for terminating the Signal thread.
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 }
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 }
260 void 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);
268 const char thread_name[] = "Signal Dispatcher";
269 Handle string = java_lang_String::create_from_str(thread_name, CHECK);
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);
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);
291 os::signal_init_pd();
293 { MutexLocker mu(Threads_lock);
294 JavaThread* signal_thread = new JavaThread(&signal_thread_entry);
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 }
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());
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 }
319 void os::terminate_signal_thread() {
320 if (!ReduceSignalUsage)
321 signal_notify(sigexitnum_pd());
322 }
325 // --------------------- loading libraries ---------------------
327 typedef jint (JNICALL *JNI_OnLoad_t)(JavaVM *, void *);
328 extern struct JavaVM_ main_vm;
330 static void* _native_java_library = NULL;
332 void* os::native_java_library() {
333 if (_native_java_library == NULL) {
334 char buffer[JVM_MAXPATHLEN];
335 char ebuf[1024];
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));
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 }
375 // --------------------- heap allocation utilities ---------------------
377 char *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 }
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 */
405 #ifdef ASSERT
406 inline 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 }
413 u_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 }
423 u_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 }
433 void 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 }
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 }
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 }
475 void 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 }
482 void 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
501 void* os::malloc(size_t size) {
502 NOT_PRODUCT(num_mallocs++);
503 NOT_PRODUCT(alloc_bytes += size);
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 }
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 }
535 void* 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 }
569 void 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 }
602 void os::init_random(long initval) {
603 _rand_seed = initval;
604 }
607 long 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");
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;
626 // if q overflowed, ignore the overflow and increment q
627 if (lo > m) {
628 lo &= m;
629 ++lo;
630 }
631 lo += hi >> 15;
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 }
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.
652 void 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 }
660 //---------------------------------------------------------------------------
661 // Helper functions for fatal error handler
663 void os::print_hex_dump(outputStream* st, address start, address end, int unitsize) {
664 assert(unitsize == 1 || unitsize == 2 || unitsize == 4 || unitsize == 8, "just checking");
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 }
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 }
698 void 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:");
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 }
713 void 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 }
723 void 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.
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 }
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.
739 bool 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
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);
756 uintptr_t usp = (uintptr_t)fr->sp();
757 if ((usp & sp_align_mask) != 0) return true;
759 uintptr_t ufp = (uintptr_t)fr->fp();
760 if ((ufp & fp_align_mask) != 0) return true;
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;
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;
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;
777 return false;
778 }
780 #ifdef ASSERT
781 extern "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;
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!");
795 // calculate mean and variance of the random sequence
796 mean += u;
797 variance += (u*u);
798 }
799 mean /= reps;
800 variance /= (reps - 1);
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
814 // Set up the boot classpath.
816 char* 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");
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 }
833 char* formatted_path = NEW_C_HEAP_ARRAY(char, formatted_path_len + 1);
834 if (formatted_path == NULL) {
835 return NULL;
836 }
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';
859 assert((q - formatted_path) == formatted_path_len, "formatted_path size botched");
860 return formatted_path;
861 }
864 bool os::set_boot_path(char fileSep, char pathSep) {
866 const char* home = Arguments::get_java_home();
867 int home_len = (int)strlen(home);
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);
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);
892 return true;
893 }
895 void 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 }
905 static volatile intptr_t SerializePageLock = 0;
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.
910 void 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 }
924 // Serialize all thread state variables
925 void 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 }
939 // Returns true if the current stack pointer is above the stack shadow
940 // pages, false otherwise.
942 bool 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 dependent 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 }
959 size_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;
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 }
974 if (sz <= max_page_size) {
975 // The largest page size that satisfies the min_pages requirement.
976 return sz;
977 }
978 }
979 }
981 return vm_page_size();
982 }
984 #ifndef PRODUCT
985 void 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
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.
1011 bool 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;
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 }