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 "precompiled.hpp"
26 #include "classfile/classLoader.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/icBuffer.hpp"
31 #include "code/vtableStubs.hpp"
32 #include "gc_implementation/shared/vmGCOperations.hpp"
33 #include "interpreter/interpreter.hpp"
34 #include "memory/allocation.inline.hpp"
35 #include "oops/oop.inline.hpp"
36 #include "prims/jvm.h"
37 #include "prims/jvm_misc.hpp"
38 #include "prims/privilegedStack.hpp"
39 #include "runtime/arguments.hpp"
40 #include "runtime/frame.inline.hpp"
41 #include "runtime/hpi.hpp"
42 #include "runtime/interfaceSupport.hpp"
43 #include "runtime/java.hpp"
44 #include "runtime/javaCalls.hpp"
45 #include "runtime/mutexLocker.hpp"
46 #include "runtime/os.hpp"
47 #include "runtime/stubRoutines.hpp"
48 #include "services/attachListener.hpp"
49 #include "services/threadService.hpp"
50 #include "utilities/defaultStream.hpp"
51 #include "utilities/events.hpp"
52 #ifdef TARGET_OS_FAMILY_linux
53 # include "os_linux.inline.hpp"
54 # include "thread_linux.inline.hpp"
55 #endif
56 #ifdef TARGET_OS_FAMILY_solaris
57 # include "os_solaris.inline.hpp"
58 # include "thread_solaris.inline.hpp"
59 #endif
60 #ifdef TARGET_OS_FAMILY_windows
61 # include "os_windows.inline.hpp"
62 # include "thread_windows.inline.hpp"
63 #endif
64
65 # include <signal.h>
66
67 OSThread* os::_starting_thread = NULL;
68 address os::_polling_page = NULL;
69 volatile int32_t* os::_mem_serialize_page = NULL;
70 uintptr_t os::_serialize_page_mask = 0;
71 long os::_rand_seed = 1;
72 int os::_processor_count = 0;
73 size_t os::_page_sizes[os::page_sizes_max];
74
75 #ifndef PRODUCT
76 int os::num_mallocs = 0; // # of calls to malloc/realloc
77 size_t os::alloc_bytes = 0; // # of bytes allocated
78 int os::num_frees = 0; // # of calls to free
79 #endif
80
81 // Fill in buffer with current local time as an ISO-8601 string.
82 // E.g., yyyy-mm-ddThh:mm:ss-zzzz.
83 // Returns buffer, or NULL if it failed.
84 // This would mostly be a call to
85 // strftime(...., "%Y-%m-%d" "T" "%H:%M:%S" "%z", ....)
86 // except that on Windows the %z behaves badly, so we do it ourselves.
87 // Also, people wanted milliseconds on there,
88 // and strftime doesn't do milliseconds.
89 char* os::iso8601_time(char* buffer, size_t buffer_length) {
90 // Output will be of the form "YYYY-MM-DDThh:mm:ss.mmm+zzzz\0"
91 // 1 2
92 // 12345678901234567890123456789
93 static const char* iso8601_format =
94 "%04d-%02d-%02dT%02d:%02d:%02d.%03d%c%02d%02d";
95 static const size_t needed_buffer = 29;
96
97 // Sanity check the arguments
98 if (buffer == NULL) {
99 assert(false, "NULL buffer");
100 return NULL;
101 }
102 if (buffer_length < needed_buffer) {
103 assert(false, "buffer_length too small");
104 return NULL;
105 }
106 // Get the current time
107 jlong milliseconds_since_19700101 = javaTimeMillis();
108 const int milliseconds_per_microsecond = 1000;
109 const time_t seconds_since_19700101 =
110 milliseconds_since_19700101 / milliseconds_per_microsecond;
111 const int milliseconds_after_second =
112 milliseconds_since_19700101 % milliseconds_per_microsecond;
113 // Convert the time value to a tm and timezone variable
114 struct tm time_struct;
115 if (localtime_pd(&seconds_since_19700101, &time_struct) == NULL) {
116 assert(false, "Failed localtime_pd");
117 return NULL;
118 }
119 const time_t zone = timezone;
120
121 // If daylight savings time is in effect,
122 // we are 1 hour East of our time zone
123 const time_t seconds_per_minute = 60;
124 const time_t minutes_per_hour = 60;
125 const time_t seconds_per_hour = seconds_per_minute * minutes_per_hour;
126 time_t UTC_to_local = zone;
127 if (time_struct.tm_isdst > 0) {
128 UTC_to_local = UTC_to_local - seconds_per_hour;
129 }
130 // Compute the time zone offset.
131 // localtime_pd() sets timezone to the difference (in seconds)
132 // between UTC and and local time.
133 // ISO 8601 says we need the difference between local time and UTC,
134 // we change the sign of the localtime_pd() result.
135 const time_t local_to_UTC = -(UTC_to_local);
136 // Then we have to figure out if if we are ahead (+) or behind (-) UTC.
137 char sign_local_to_UTC = '+';
138 time_t abs_local_to_UTC = local_to_UTC;
139 if (local_to_UTC < 0) {
140 sign_local_to_UTC = '-';
141 abs_local_to_UTC = -(abs_local_to_UTC);
142 }
143 // Convert time zone offset seconds to hours and minutes.
144 const time_t zone_hours = (abs_local_to_UTC / seconds_per_hour);
145 const time_t zone_min =
146 ((abs_local_to_UTC % seconds_per_hour) / seconds_per_minute);
147
148 // Print an ISO 8601 date and time stamp into the buffer
149 const int year = 1900 + time_struct.tm_year;
150 const int month = 1 + time_struct.tm_mon;
151 const int printed = jio_snprintf(buffer, buffer_length, iso8601_format,
152 year,
153 month,
154 time_struct.tm_mday,
155 time_struct.tm_hour,
156 time_struct.tm_min,
157 time_struct.tm_sec,
158 milliseconds_after_second,
159 sign_local_to_UTC,
160 zone_hours,
161 zone_min);
162 if (printed == 0) {
163 assert(false, "Failed jio_printf");
164 return NULL;
165 }
166 return buffer;
167 }
168
169 OSReturn os::set_priority(Thread* thread, ThreadPriority p) {
170 #ifdef ASSERT
171 if (!(!thread->is_Java_thread() ||
172 Thread::current() == thread ||
173 Threads_lock->owned_by_self()
174 || thread->is_Compiler_thread()
175 )) {
176 assert(false, "possibility of dangling Thread pointer");
177 }
178 #endif
179
180 if (p >= MinPriority && p <= MaxPriority) {
181 int priority = java_to_os_priority[p];
182 return set_native_priority(thread, priority);
183 } else {
184 assert(false, "Should not happen");
185 return OS_ERR;
186 }
187 }
188
189
190 OSReturn os::get_priority(const Thread* const thread, ThreadPriority& priority) {
191 int p;
192 int os_prio;
193 OSReturn ret = get_native_priority(thread, &os_prio);
194 if (ret != OS_OK) return ret;
195
196 for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] > os_prio; p--) ;
197 priority = (ThreadPriority)p;
198 return OS_OK;
199 }
200
201
202 // --------------------- sun.misc.Signal (optional) ---------------------
203
204
205 // SIGBREAK is sent by the keyboard to query the VM state
206 #ifndef SIGBREAK
207 #define SIGBREAK SIGQUIT
208 #endif
209
210 // sigexitnum_pd is a platform-specific special signal used for terminating the Signal thread.
211
212
213 static void signal_thread_entry(JavaThread* thread, TRAPS) {
214 os::set_priority(thread, NearMaxPriority);
215 while (true) {
216 int sig;
217 {
218 // FIXME : Currently we have not decieded what should be the status
219 // for this java thread blocked here. Once we decide about
220 // that we should fix this.
221 sig = os::signal_wait();
222 }
223 if (sig == os::sigexitnum_pd()) {
224 // Terminate the signal thread
225 return;
226 }
227
228 switch (sig) {
229 case SIGBREAK: {
230 // Check if the signal is a trigger to start the Attach Listener - in that
231 // case don't print stack traces.
232 if (!DisableAttachMechanism && AttachListener::is_init_trigger()) {
233 continue;
234 }
235 // Print stack traces
236 // Any SIGBREAK operations added here should make sure to flush
237 // the output stream (e.g. tty->flush()) after output. See 4803766.
238 // Each module also prints an extra carriage return after its output.
239 VM_PrintThreads op;
240 VMThread::execute(&op);
241 VM_PrintJNI jni_op;
242 VMThread::execute(&jni_op);
243 VM_FindDeadlocks op1(tty);
244 VMThread::execute(&op1);
245 Universe::print_heap_at_SIGBREAK();
246 if (PrintClassHistogram) {
247 VM_GC_HeapInspection op1(gclog_or_tty, true /* force full GC before heap inspection */,
248 true /* need_prologue */);
249 VMThread::execute(&op1);
250 }
251 if (JvmtiExport::should_post_data_dump()) {
252 JvmtiExport::post_data_dump();
253 }
254 break;
255 }
256 default: {
257 // Dispatch the signal to java
258 HandleMark hm(THREAD);
259 klassOop k = SystemDictionary::resolve_or_null(vmSymbolHandles::sun_misc_Signal(), THREAD);
260 KlassHandle klass (THREAD, k);
261 if (klass.not_null()) {
262 JavaValue result(T_VOID);
263 JavaCallArguments args;
264 args.push_int(sig);
265 JavaCalls::call_static(
266 &result,
267 klass,
268 vmSymbolHandles::dispatch_name(),
269 vmSymbolHandles::int_void_signature(),
270 &args,
271 THREAD
272 );
273 }
274 if (HAS_PENDING_EXCEPTION) {
275 // tty is initialized early so we don't expect it to be null, but
276 // if it is we can't risk doing an initialization that might
277 // trigger additional out-of-memory conditions
278 if (tty != NULL) {
279 char klass_name[256];
280 char tmp_sig_name[16];
281 const char* sig_name = "UNKNOWN";
282 instanceKlass::cast(PENDING_EXCEPTION->klass())->
283 name()->as_klass_external_name(klass_name, 256);
284 if (os::exception_name(sig, tmp_sig_name, 16) != NULL)
285 sig_name = tmp_sig_name;
286 warning("Exception %s occurred dispatching signal %s to handler"
287 "- the VM may need to be forcibly terminated",
288 klass_name, sig_name );
289 }
290 CLEAR_PENDING_EXCEPTION;
291 }
292 }
293 }
294 }
295 }
296
297
298 void os::signal_init() {
299 if (!ReduceSignalUsage) {
300 // Setup JavaThread for processing signals
301 EXCEPTION_MARK;
302 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK);
303 instanceKlassHandle klass (THREAD, k);
304 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
305
306 const char thread_name[] = "Signal Dispatcher";
307 Handle string = java_lang_String::create_from_str(thread_name, CHECK);
308
309 // Initialize thread_oop to put it into the system threadGroup
310 Handle thread_group (THREAD, Universe::system_thread_group());
311 JavaValue result(T_VOID);
312 JavaCalls::call_special(&result, thread_oop,
313 klass,
314 vmSymbolHandles::object_initializer_name(),
315 vmSymbolHandles::threadgroup_string_void_signature(),
316 thread_group,
317 string,
318 CHECK);
319
320 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
321 JavaCalls::call_special(&result,
322 thread_group,
323 group,
324 vmSymbolHandles::add_method_name(),
325 vmSymbolHandles::thread_void_signature(),
326 thread_oop, // ARG 1
327 CHECK);
328
329 os::signal_init_pd();
330
331 { MutexLocker mu(Threads_lock);
332 JavaThread* signal_thread = new JavaThread(&signal_thread_entry);
333
334 // At this point it may be possible that no osthread was created for the
335 // JavaThread due to lack of memory. We would have to throw an exception
336 // in that case. However, since this must work and we do not allow
337 // exceptions anyway, check and abort if this fails.
338 if (signal_thread == NULL || signal_thread->osthread() == NULL) {
339 vm_exit_during_initialization("java.lang.OutOfMemoryError",
340 "unable to create new native thread");
341 }
342
343 java_lang_Thread::set_thread(thread_oop(), signal_thread);
344 java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);
345 java_lang_Thread::set_daemon(thread_oop());
346
347 signal_thread->set_threadObj(thread_oop());
348 Threads::add(signal_thread);
349 Thread::start(signal_thread);
350 }
351 // Handle ^BREAK
352 os::signal(SIGBREAK, os::user_handler());
353 }
354 }
355
356
357 void os::terminate_signal_thread() {
358 if (!ReduceSignalUsage)
359 signal_notify(sigexitnum_pd());
360 }
361
362
363 // --------------------- loading libraries ---------------------
364
365 typedef jint (JNICALL *JNI_OnLoad_t)(JavaVM *, void *);
366 extern struct JavaVM_ main_vm;
367
368 static void* _native_java_library = NULL;
369
370 void* os::native_java_library() {
371 if (_native_java_library == NULL) {
372 char buffer[JVM_MAXPATHLEN];
373 char ebuf[1024];
374
375 // Try to load verify dll first. In 1.3 java dll depends on it and is not
376 // always able to find it when the loading executable is outside the JDK.
377 // In order to keep working with 1.2 we ignore any loading errors.
378 dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), "verify");
379 dll_load(buffer, ebuf, sizeof(ebuf));
380
381 // Load java dll
382 dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), "java");
383 _native_java_library = dll_load(buffer, ebuf, sizeof(ebuf));
384 if (_native_java_library == NULL) {
385 vm_exit_during_initialization("Unable to load native library", ebuf);
386 }
387 }
388 static jboolean onLoaded = JNI_FALSE;
389 if (onLoaded) {
390 // We may have to wait to fire OnLoad until TLS is initialized.
391 if (ThreadLocalStorage::is_initialized()) {
392 // The JNI_OnLoad handling is normally done by method load in
393 // java.lang.ClassLoader$NativeLibrary, but the VM loads the base library
394 // explicitly so we have to check for JNI_OnLoad as well
395 const char *onLoadSymbols[] = JNI_ONLOAD_SYMBOLS;
396 JNI_OnLoad_t JNI_OnLoad = CAST_TO_FN_PTR(
397 JNI_OnLoad_t, dll_lookup(_native_java_library, onLoadSymbols[0]));
398 if (JNI_OnLoad != NULL) {
399 JavaThread* thread = JavaThread::current();
400 ThreadToNativeFromVM ttn(thread);
401 HandleMark hm(thread);
402 jint ver = (*JNI_OnLoad)(&main_vm, NULL);
403 onLoaded = JNI_TRUE;
404 if (!Threads::is_supported_jni_version_including_1_1(ver)) {
405 vm_exit_during_initialization("Unsupported JNI version");
406 }
407 }
408 }
409 }
410 return _native_java_library;
411 }
412
413 // --------------------- heap allocation utilities ---------------------
414
415 char *os::strdup(const char *str) {
416 size_t size = strlen(str);
417 char *dup_str = (char *)malloc(size + 1);
418 if (dup_str == NULL) return NULL;
419 strcpy(dup_str, str);
420 return dup_str;
421 }
422
423
424
425 #ifdef ASSERT
426 #define space_before (MallocCushion + sizeof(double))
427 #define space_after MallocCushion
428 #define size_addr_from_base(p) (size_t*)(p + space_before - sizeof(size_t))
429 #define size_addr_from_obj(p) ((size_t*)p - 1)
430 // MallocCushion: size of extra cushion allocated around objects with +UseMallocOnly
431 // NB: cannot be debug variable, because these aren't set from the command line until
432 // *after* the first few allocs already happened
433 #define MallocCushion 16
434 #else
435 #define space_before 0
436 #define space_after 0
437 #define size_addr_from_base(p) should not use w/o ASSERT
438 #define size_addr_from_obj(p) should not use w/o ASSERT
439 #define MallocCushion 0
440 #endif
441 #define paranoid 0 /* only set to 1 if you suspect checking code has bug */
442
443 #ifdef ASSERT
444 inline size_t get_size(void* obj) {
445 size_t size = *size_addr_from_obj(obj);
446 if (size < 0) {
447 fatal(err_msg("free: size field of object #" PTR_FORMAT " was overwritten ("
448 SIZE_FORMAT ")", obj, size));
449 }
450 return size;
451 }
452
453 u_char* find_cushion_backwards(u_char* start) {
454 u_char* p = start;
455 while (p[ 0] != badResourceValue || p[-1] != badResourceValue ||
456 p[-2] != badResourceValue || p[-3] != badResourceValue) p--;
457 // ok, we have four consecutive marker bytes; find start
458 u_char* q = p - 4;
459 while (*q == badResourceValue) q--;
460 return q + 1;
461 }
462
463 u_char* find_cushion_forwards(u_char* start) {
464 u_char* p = start;
465 while (p[0] != badResourceValue || p[1] != badResourceValue ||
466 p[2] != badResourceValue || p[3] != badResourceValue) p++;
467 // ok, we have four consecutive marker bytes; find end of cushion
468 u_char* q = p + 4;
469 while (*q == badResourceValue) q++;
470 return q - MallocCushion;
471 }
472
473 void print_neighbor_blocks(void* ptr) {
474 // find block allocated before ptr (not entirely crash-proof)
475 if (MallocCushion < 4) {
476 tty->print_cr("### cannot find previous block (MallocCushion < 4)");
477 return;
478 }
479 u_char* start_of_this_block = (u_char*)ptr - space_before;
480 u_char* end_of_prev_block_data = start_of_this_block - space_after -1;
481 // look for cushion in front of prev. block
482 u_char* start_of_prev_block = find_cushion_backwards(end_of_prev_block_data);
483 ptrdiff_t size = *size_addr_from_base(start_of_prev_block);
484 u_char* obj = start_of_prev_block + space_before;
485 if (size <= 0 ) {
486 // start is bad; mayhave been confused by OS data inbetween objects
487 // search one more backwards
488 start_of_prev_block = find_cushion_backwards(start_of_prev_block);
489 size = *size_addr_from_base(start_of_prev_block);
490 obj = start_of_prev_block + space_before;
491 }
492
493 if (start_of_prev_block + space_before + size + space_after == start_of_this_block) {
494 tty->print_cr("### previous object: %p (%ld bytes)", obj, size);
495 } else {
496 tty->print_cr("### previous object (not sure if correct): %p (%ld bytes)", obj, size);
497 }
498
499 // now find successor block
500 u_char* start_of_next_block = (u_char*)ptr + *size_addr_from_obj(ptr) + space_after;
501 start_of_next_block = find_cushion_forwards(start_of_next_block);
502 u_char* next_obj = start_of_next_block + space_before;
503 ptrdiff_t next_size = *size_addr_from_base(start_of_next_block);
504 if (start_of_next_block[0] == badResourceValue &&
505 start_of_next_block[1] == badResourceValue &&
506 start_of_next_block[2] == badResourceValue &&
507 start_of_next_block[3] == badResourceValue) {
508 tty->print_cr("### next object: %p (%ld bytes)", next_obj, next_size);
509 } else {
510 tty->print_cr("### next object (not sure if correct): %p (%ld bytes)", next_obj, next_size);
511 }
512 }
513
514
515 void report_heap_error(void* memblock, void* bad, const char* where) {
516 tty->print_cr("## nof_mallocs = %d, nof_frees = %d", os::num_mallocs, os::num_frees);
517 tty->print_cr("## memory stomp: byte at %p %s object %p", bad, where, memblock);
518 print_neighbor_blocks(memblock);
519 fatal("memory stomping error");
520 }
521
522 void verify_block(void* memblock) {
523 size_t size = get_size(memblock);
524 if (MallocCushion) {
525 u_char* ptr = (u_char*)memblock - space_before;
526 for (int i = 0; i < MallocCushion; i++) {
527 if (ptr[i] != badResourceValue) {
528 report_heap_error(memblock, ptr+i, "in front of");
529 }
530 }
531 u_char* end = (u_char*)memblock + size + space_after;
532 for (int j = -MallocCushion; j < 0; j++) {
533 if (end[j] != badResourceValue) {
534 report_heap_error(memblock, end+j, "after");
535 }
536 }
537 }
538 }
539 #endif
540
541 void* os::malloc(size_t size) {
542 NOT_PRODUCT(num_mallocs++);
543 NOT_PRODUCT(alloc_bytes += size);
544
545 if (size == 0) {
546 // return a valid pointer if size is zero
547 // if NULL is returned the calling functions assume out of memory.
548 size = 1;
549 }
550
551 NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
552 u_char* ptr = (u_char*)::malloc(size + space_before + space_after);
553 #ifdef ASSERT
554 if (ptr == NULL) return NULL;
555 if (MallocCushion) {
556 for (u_char* p = ptr; p < ptr + MallocCushion; p++) *p = (u_char)badResourceValue;
557 u_char* end = ptr + space_before + size;
558 for (u_char* pq = ptr+MallocCushion; pq < end; pq++) *pq = (u_char)uninitBlockPad;
559 for (u_char* q = end; q < end + MallocCushion; q++) *q = (u_char)badResourceValue;
560 }
561 // put size just before data
562 *size_addr_from_base(ptr) = size;
563 #endif
564 u_char* memblock = ptr + space_before;
565 if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
566 tty->print_cr("os::malloc caught, %lu bytes --> %p", size, memblock);
567 breakpoint();
568 }
569 debug_only(if (paranoid) verify_block(memblock));
570 if (PrintMalloc && tty != NULL) tty->print_cr("os::malloc %lu bytes --> %p", size, memblock);
571 return memblock;
572 }
573
574
575 void* os::realloc(void *memblock, size_t size) {
576 NOT_PRODUCT(num_mallocs++);
577 NOT_PRODUCT(alloc_bytes += size);
578 #ifndef ASSERT
579 return ::realloc(memblock, size);
580 #else
581 if (memblock == NULL) {
582 return os::malloc(size);
583 }
584 if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
585 tty->print_cr("os::realloc caught %p", memblock);
586 breakpoint();
587 }
588 verify_block(memblock);
589 NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
590 if (size == 0) return NULL;
591 // always move the block
592 void* ptr = malloc(size);
593 if (PrintMalloc) tty->print_cr("os::remalloc %lu bytes, %p --> %p", size, memblock, ptr);
594 // Copy to new memory if malloc didn't fail
595 if ( ptr != NULL ) {
596 memcpy(ptr, memblock, MIN2(size, get_size(memblock)));
597 if (paranoid) verify_block(ptr);
598 if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) {
599 tty->print_cr("os::realloc caught, %lu bytes --> %p", size, ptr);
600 breakpoint();
601 }
602 free(memblock);
603 }
604 return ptr;
605 #endif
606 }
607
608
609 void os::free(void *memblock) {
610 NOT_PRODUCT(num_frees++);
611 #ifdef ASSERT
612 if (memblock == NULL) return;
613 if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
614 if (tty != NULL) tty->print_cr("os::free caught %p", memblock);
615 breakpoint();
616 }
617 verify_block(memblock);
618 if (PrintMalloc && tty != NULL)
619 // tty->print_cr("os::free %p", memblock);
620 fprintf(stderr, "os::free %p\n", memblock);
621 NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
622 // Added by detlefs.
623 if (MallocCushion) {
624 u_char* ptr = (u_char*)memblock - space_before;
625 for (u_char* p = ptr; p < ptr + MallocCushion; p++) {
626 guarantee(*p == badResourceValue,
627 "Thing freed should be malloc result.");
628 *p = (u_char)freeBlockPad;
629 }
630 size_t size = get_size(memblock);
631 u_char* end = ptr + space_before + size;
632 for (u_char* q = end; q < end + MallocCushion; q++) {
633 guarantee(*q == badResourceValue,
634 "Thing freed should be malloc result.");
635 *q = (u_char)freeBlockPad;
636 }
637 }
638 #endif
639 ::free((char*)memblock - space_before);
640 }
641
642 void os::init_random(long initval) {
643 _rand_seed = initval;
644 }
645
646
647 long os::random() {
648 /* standard, well-known linear congruential random generator with
649 * next_rand = (16807*seed) mod (2**31-1)
650 * see
651 * (1) "Random Number Generators: Good Ones Are Hard to Find",
652 * S.K. Park and K.W. Miller, Communications of the ACM 31:10 (Oct 1988),
653 * (2) "Two Fast Implementations of the 'Minimal Standard' Random
654 * Number Generator", David G. Carta, Comm. ACM 33, 1 (Jan 1990), pp. 87-88.
655 */
656 const long a = 16807;
657 const unsigned long m = 2147483647;
658 const long q = m / a; assert(q == 127773, "weird math");
659 const long r = m % a; assert(r == 2836, "weird math");
660
661 // compute az=2^31p+q
662 unsigned long lo = a * (long)(_rand_seed & 0xFFFF);
663 unsigned long hi = a * (long)((unsigned long)_rand_seed >> 16);
664 lo += (hi & 0x7FFF) << 16;
665
666 // if q overflowed, ignore the overflow and increment q
667 if (lo > m) {
668 lo &= m;
669 ++lo;
670 }
671 lo += hi >> 15;
672
673 // if (p+q) overflowed, ignore the overflow and increment (p+q)
674 if (lo > m) {
675 lo &= m;
676 ++lo;
677 }
678 return (_rand_seed = lo);
679 }
680
681 // The INITIALIZED state is distinguished from the SUSPENDED state because the
682 // conditions in which a thread is first started are different from those in which
683 // a suspension is resumed. These differences make it hard for us to apply the
684 // tougher checks when starting threads that we want to do when resuming them.
685 // However, when start_thread is called as a result of Thread.start, on a Java
686 // thread, the operation is synchronized on the Java Thread object. So there
687 // cannot be a race to start the thread and hence for the thread to exit while
688 // we are working on it. Non-Java threads that start Java threads either have
689 // to do so in a context in which races are impossible, or should do appropriate
690 // locking.
691
692 void os::start_thread(Thread* thread) {
693 // guard suspend/resume
694 MutexLockerEx ml(thread->SR_lock(), Mutex::_no_safepoint_check_flag);
695 OSThread* osthread = thread->osthread();
696 osthread->set_state(RUNNABLE);
697 pd_start_thread(thread);
698 }
699
700 //---------------------------------------------------------------------------
701 // Helper functions for fatal error handler
702
703 void os::print_hex_dump(outputStream* st, address start, address end, int unitsize) {
704 assert(unitsize == 1 || unitsize == 2 || unitsize == 4 || unitsize == 8, "just checking");
705
706 int cols = 0;
707 int cols_per_line = 0;
708 switch (unitsize) {
709 case 1: cols_per_line = 16; break;
710 case 2: cols_per_line = 8; break;
711 case 4: cols_per_line = 4; break;
712 case 8: cols_per_line = 2; break;
713 default: return;
714 }
715
716 address p = start;
717 st->print(PTR_FORMAT ": ", start);
718 while (p < end) {
719 switch (unitsize) {
720 case 1: st->print("%02x", *(u1*)p); break;
721 case 2: st->print("%04x", *(u2*)p); break;
722 case 4: st->print("%08x", *(u4*)p); break;
723 case 8: st->print("%016" FORMAT64_MODIFIER "x", *(u8*)p); break;
724 }
725 p += unitsize;
726 cols++;
727 if (cols >= cols_per_line && p < end) {
728 cols = 0;
729 st->cr();
730 st->print(PTR_FORMAT ": ", p);
731 } else {
732 st->print(" ");
733 }
734 }
735 st->cr();
736 }
737
738 void os::print_environment_variables(outputStream* st, const char** env_list,
739 char* buffer, int len) {
740 if (env_list) {
741 st->print_cr("Environment Variables:");
742
743 for (int i = 0; env_list[i] != NULL; i++) {
744 if (getenv(env_list[i], buffer, len)) {
745 st->print(env_list[i]);
746 st->print("=");
747 st->print_cr(buffer);
748 }
749 }
750 }
751 }
752
753 void os::print_cpu_info(outputStream* st) {
754 // cpu
755 st->print("CPU:");
756 st->print("total %d", os::processor_count());
757 // It's not safe to query number of active processors after crash
758 // st->print("(active %d)", os::active_processor_count());
759 st->print(" %s", VM_Version::cpu_features());
760 st->cr();
761 }
762
763 void os::print_date_and_time(outputStream *st) {
764 time_t tloc;
765 (void)time(&tloc);
766 st->print("time: %s", ctime(&tloc)); // ctime adds newline.
767
768 double t = os::elapsedTime();
769 // NOTE: It tends to crash after a SEGV if we want to printf("%f",...) in
770 // Linux. Must be a bug in glibc ? Workaround is to round "t" to int
771 // before printf. We lost some precision, but who cares?
772 st->print_cr("elapsed time: %d seconds", (int)t);
773 }
774
775 // moved from debug.cpp (used to be find()) but still called from there
776 // The print_pc parameter is only set by the debug code in one case
777 void os::print_location(outputStream* st, intptr_t x, bool print_pc) {
778 address addr = (address)x;
779 CodeBlob* b = CodeCache::find_blob_unsafe(addr);
780 if (b != NULL) {
781 if (b->is_buffer_blob()) {
782 // the interpreter is generated into a buffer blob
783 InterpreterCodelet* i = Interpreter::codelet_containing(addr);
784 if (i != NULL) {
785 i->print_on(st);
786 return;
787 }
788 if (Interpreter::contains(addr)) {
789 st->print_cr(INTPTR_FORMAT " is pointing into interpreter code"
790 " (not bytecode specific)", addr);
791 return;
792 }
793 //
794 if (AdapterHandlerLibrary::contains(b)) {
795 st->print_cr("Printing AdapterHandler");
796 AdapterHandlerLibrary::print_handler_on(st, b);
797 }
798 // the stubroutines are generated into a buffer blob
799 StubCodeDesc* d = StubCodeDesc::desc_for(addr);
800 if (d != NULL) {
801 d->print_on(st);
802 if (print_pc) st->cr();
803 return;
804 }
805 if (StubRoutines::contains(addr)) {
806 st->print_cr(INTPTR_FORMAT " is pointing to an (unnamed) "
807 "stub routine", addr);
808 return;
809 }
810 // the InlineCacheBuffer is using stubs generated into a buffer blob
811 if (InlineCacheBuffer::contains(addr)) {
812 st->print_cr(INTPTR_FORMAT " is pointing into InlineCacheBuffer", addr);
813 return;
814 }
815 VtableStub* v = VtableStubs::stub_containing(addr);
816 if (v != NULL) {
817 v->print_on(st);
818 return;
819 }
820 }
821 if (print_pc && b->is_nmethod()) {
822 ResourceMark rm;
823 st->print("%#p: Compiled ", addr);
824 ((nmethod*)b)->method()->print_value_on(st);
825 st->print(" = (CodeBlob*)" INTPTR_FORMAT, b);
826 st->cr();
827 return;
828 }
829 if ( b->is_nmethod()) {
830 if (b->is_zombie()) {
831 st->print_cr(INTPTR_FORMAT " is zombie nmethod", b);
832 } else if (b->is_not_entrant()) {
833 st->print_cr(INTPTR_FORMAT " is non-entrant nmethod", b);
834 }
835 }
836 b->print_on(st);
837 return;
838 }
839
840 if (Universe::heap()->is_in(addr)) {
841 HeapWord* p = Universe::heap()->block_start(addr);
842 bool print = false;
843 // If we couldn't find it it just may mean that heap wasn't parseable
844 // See if we were just given an oop directly
845 if (p != NULL && Universe::heap()->block_is_obj(p)) {
846 print = true;
847 } else if (p == NULL && ((oopDesc*)addr)->is_oop()) {
848 p = (HeapWord*) addr;
849 print = true;
850 }
851 if (print) {
852 oop(p)->print_on(st);
853 if (p != (HeapWord*)x && oop(p)->is_constMethod() &&
854 constMethodOop(p)->contains(addr)) {
855 Thread *thread = Thread::current();
856 HandleMark hm(thread);
857 methodHandle mh (thread, constMethodOop(p)->method());
858 if (!mh->is_native()) {
859 st->print_cr("bci_from(%p) = %d; print_codes():",
860 addr, mh->bci_from(address(x)));
861 mh->print_codes_on(st);
862 }
863 }
864 return;
865 }
866 } else {
867 if (Universe::heap()->is_in_reserved(addr)) {
868 st->print_cr(INTPTR_FORMAT " is an unallocated location "
869 "in the heap", addr);
870 return;
871 }
872 }
873 if (JNIHandles::is_global_handle((jobject) addr)) {
874 st->print_cr(INTPTR_FORMAT " is a global jni handle", addr);
875 return;
876 }
877 if (JNIHandles::is_weak_global_handle((jobject) addr)) {
878 st->print_cr(INTPTR_FORMAT " is a weak global jni handle", addr);
879 return;
880 }
881 #ifndef PRODUCT
882 // we don't keep the block list in product mode
883 if (JNIHandleBlock::any_contains((jobject) addr)) {
884 st->print_cr(INTPTR_FORMAT " is a local jni handle", addr);
885 return;
886 }
887 #endif
888
889 for(JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
890 // Check for privilege stack
891 if (thread->privileged_stack_top() != NULL &&
892 thread->privileged_stack_top()->contains(addr)) {
893 st->print_cr(INTPTR_FORMAT " is pointing into the privilege stack "
894 "for thread: " INTPTR_FORMAT, addr, thread);
895 thread->print_on(st);
896 return;
897 }
898 // If the addr is a java thread print information about that.
899 if (addr == (address)thread) {
900 thread->print_on(st);
901 return;
902 }
903 // If the addr is in the stack region for this thread then report that
904 // and print thread info
905 if (thread->stack_base() >= addr &&
906 addr > (thread->stack_base() - thread->stack_size())) {
907 st->print_cr(INTPTR_FORMAT " is pointing into the stack for thread: "
908 INTPTR_FORMAT, addr, thread);
909 thread->print_on(st);
910 return;
911 }
912
913 }
914 // Try an OS specific find
915 if (os::find(addr, st)) {
916 return;
917 }
918
919 st->print_cr(INTPTR_FORMAT " is pointing to unknown location", addr);
920 }
921
922 // Looks like all platforms except IA64 can use the same function to check
923 // if C stack is walkable beyond current frame. The check for fp() is not
924 // necessary on Sparc, but it's harmless.
925 bool os::is_first_C_frame(frame* fr) {
926 #ifdef IA64
927 // In order to walk native frames on Itanium, we need to access the unwind
928 // table, which is inside ELF. We don't want to parse ELF after fatal error,
929 // so return true for IA64. If we need to support C stack walking on IA64,
930 // this function needs to be moved to CPU specific files, as fp() on IA64
931 // is register stack, which grows towards higher memory address.
932 return true;
933 #endif
934
935 // Load up sp, fp, sender sp and sender fp, check for reasonable values.
936 // Check usp first, because if that's bad the other accessors may fault
937 // on some architectures. Ditto ufp second, etc.
938 uintptr_t fp_align_mask = (uintptr_t)(sizeof(address)-1);
939 // sp on amd can be 32 bit aligned.
940 uintptr_t sp_align_mask = (uintptr_t)(sizeof(int)-1);
941
942 uintptr_t usp = (uintptr_t)fr->sp();
943 if ((usp & sp_align_mask) != 0) return true;
944
945 uintptr_t ufp = (uintptr_t)fr->fp();
946 if ((ufp & fp_align_mask) != 0) return true;
947
948 uintptr_t old_sp = (uintptr_t)fr->sender_sp();
949 if ((old_sp & sp_align_mask) != 0) return true;
950 if (old_sp == 0 || old_sp == (uintptr_t)-1) return true;
951
952 uintptr_t old_fp = (uintptr_t)fr->link();
953 if ((old_fp & fp_align_mask) != 0) return true;
954 if (old_fp == 0 || old_fp == (uintptr_t)-1 || old_fp == ufp) return true;
955
956 // stack grows downwards; if old_fp is below current fp or if the stack
957 // frame is too large, either the stack is corrupted or fp is not saved
958 // on stack (i.e. on x86, ebp may be used as general register). The stack
959 // is not walkable beyond current frame.
960 if (old_fp < ufp) return true;
961 if (old_fp - ufp > 64 * K) return true;
962
963 return false;
964 }
965
966 #ifdef ASSERT
967 extern "C" void test_random() {
968 const double m = 2147483647;
969 double mean = 0.0, variance = 0.0, t;
970 long reps = 10000;
971 unsigned long seed = 1;
972
973 tty->print_cr("seed %ld for %ld repeats...", seed, reps);
974 os::init_random(seed);
975 long num;
976 for (int k = 0; k < reps; k++) {
977 num = os::random();
978 double u = (double)num / m;
979 assert(u >= 0.0 && u <= 1.0, "bad random number!");
980
981 // calculate mean and variance of the random sequence
982 mean += u;
983 variance += (u*u);
984 }
985 mean /= reps;
986 variance /= (reps - 1);
987
988 assert(num == 1043618065, "bad seed");
989 tty->print_cr("mean of the 1st 10000 numbers: %f", mean);
990 tty->print_cr("variance of the 1st 10000 numbers: %f", variance);
991 const double eps = 0.0001;
992 t = fabsd(mean - 0.5018);
993 assert(t < eps, "bad mean");
994 t = (variance - 0.3355) < 0.0 ? -(variance - 0.3355) : variance - 0.3355;
995 assert(t < eps, "bad variance");
996 }
997 #endif
998
999
1000 // Set up the boot classpath.
1001
1002 char* os::format_boot_path(const char* format_string,
1003 const char* home,
1004 int home_len,
1005 char fileSep,
1006 char pathSep) {
1007 assert((fileSep == '/' && pathSep == ':') ||
1008 (fileSep == '\\' && pathSep == ';'), "unexpected seperator chars");
1009
1010 // Scan the format string to determine the length of the actual
1011 // boot classpath, and handle platform dependencies as well.
1012 int formatted_path_len = 0;
1013 const char* p;
1014 for (p = format_string; *p != 0; ++p) {
1015 if (*p == '%') formatted_path_len += home_len - 1;
1016 ++formatted_path_len;
1017 }
1018
1019 char* formatted_path = NEW_C_HEAP_ARRAY(char, formatted_path_len + 1);
1020 if (formatted_path == NULL) {
1021 return NULL;
1022 }
1023
1024 // Create boot classpath from format, substituting separator chars and
1025 // java home directory.
1026 char* q = formatted_path;
1027 for (p = format_string; *p != 0; ++p) {
1028 switch (*p) {
1029 case '%':
1030 strcpy(q, home);
1031 q += home_len;
1032 break;
1033 case '/':
1034 *q++ = fileSep;
1035 break;
1036 case ':':
1037 *q++ = pathSep;
1038 break;
1039 default:
1040 *q++ = *p;
1041 }
1042 }
1043 *q = '\0';
1044
1045 assert((q - formatted_path) == formatted_path_len, "formatted_path size botched");
1046 return formatted_path;
1047 }
1048
1049
1050 bool os::set_boot_path(char fileSep, char pathSep) {
1051 const char* home = Arguments::get_java_home();
1052 int home_len = (int)strlen(home);
1053
1054 static const char* meta_index_dir_format = "%/lib/";
1055 static const char* meta_index_format = "%/lib/meta-index";
1056 char* meta_index = format_boot_path(meta_index_format, home, home_len, fileSep, pathSep);
1057 if (meta_index == NULL) return false;
1058 char* meta_index_dir = format_boot_path(meta_index_dir_format, home, home_len, fileSep, pathSep);
1059 if (meta_index_dir == NULL) return false;
1060 Arguments::set_meta_index_path(meta_index, meta_index_dir);
1061
1062 // Any modification to the JAR-file list, for the boot classpath must be
1063 // aligned with install/install/make/common/Pack.gmk. Note: boot class
1064 // path class JARs, are stripped for StackMapTable to reduce download size.
1065 static const char classpath_format[] =
1066 "%/lib/resources.jar:"
1067 "%/lib/rt.jar:"
1068 "%/lib/sunrsasign.jar:"
1069 "%/lib/jsse.jar:"
1070 "%/lib/jce.jar:"
1071 "%/lib/charsets.jar:"
1072
1073 // ## TEMPORARY hack to keep the legacy launcher working when
1074 // ## only the boot module is installed (cf. j.l.ClassLoader)
1075 "%/lib/modules/jdk.boot.jar:"
1076
1077 "%/classes";
1078 char* sysclasspath = format_boot_path(classpath_format, home, home_len, fileSep, pathSep);
1079 if (sysclasspath == NULL) return false;
1080 Arguments::set_sysclasspath(sysclasspath);
1081
1082 return true;
1083 }
1084
1085 /*
1086 * Splits a path, based on its separator, the number of
1087 * elements is returned back in n.
1088 * It is the callers responsibility to:
1089 * a> check the value of n, and n may be 0.
1090 * b> ignore any empty path elements
1091 * c> free up the data.
1092 */
1093 char** os::split_path(const char* path, int* n) {
1094 *n = 0;
1095 if (path == NULL || strlen(path) == 0) {
1096 return NULL;
1097 }
1098 const char psepchar = *os::path_separator();
1099 char* inpath = (char*)NEW_C_HEAP_ARRAY(char, strlen(path) + 1);
1100 if (inpath == NULL) {
1101 return NULL;
1102 }
1103 strncpy(inpath, path, strlen(path));
1104 int count = 1;
1105 char* p = strchr(inpath, psepchar);
1106 // Get a count of elements to allocate memory
1107 while (p != NULL) {
1108 count++;
1109 p++;
1110 p = strchr(p, psepchar);
1111 }
1112 char** opath = (char**) NEW_C_HEAP_ARRAY(char*, count);
1113 if (opath == NULL) {
1114 return NULL;
1115 }
1116
1117 // do the actual splitting
1118 p = inpath;
1119 for (int i = 0 ; i < count ; i++) {
1120 size_t len = strcspn(p, os::path_separator());
1121 if (len > JVM_MAXPATHLEN) {
1122 return NULL;
1123 }
1124 // allocate the string and add terminator storage
1125 char* s = (char*)NEW_C_HEAP_ARRAY(char, len + 1);
1126 if (s == NULL) {
1127 return NULL;
1128 }
1129 strncpy(s, p, len);
1130 s[len] = '\0';
1131 opath[i] = s;
1132 p += len + 1;
1133 }
1134 FREE_C_HEAP_ARRAY(char, inpath);
1135 *n = count;
1136 return opath;
1137 }
1138
1139 void os::set_memory_serialize_page(address page) {
1140 int count = log2_intptr(sizeof(class JavaThread)) - log2_intptr(64);
1141 _mem_serialize_page = (volatile int32_t *)page;
1142 // We initialize the serialization page shift count here
1143 // We assume a cache line size of 64 bytes
1144 assert(SerializePageShiftCount == count,
1145 "thread size changed, fix SerializePageShiftCount constant");
1146 set_serialize_page_mask((uintptr_t)(vm_page_size() - sizeof(int32_t)));
1147 }
1148
1149 static volatile intptr_t SerializePageLock = 0;
1150
1151 // This method is called from signal handler when SIGSEGV occurs while the current
1152 // thread tries to store to the "read-only" memory serialize page during state
1153 // transition.
1154 void os::block_on_serialize_page_trap() {
1155 if (TraceSafepoint) {
1156 tty->print_cr("Block until the serialize page permission restored");
1157 }
1158 // When VMThread is holding the SerializePageLock during modifying the
1159 // access permission of the memory serialize page, the following call
1160 // will block until the permission of that page is restored to rw.
1161 // Generally, it is unsafe to manipulate locks in signal handlers, but in
1162 // this case, it's OK as the signal is synchronous and we know precisely when
1163 // it can occur.
1164 Thread::muxAcquire(&SerializePageLock, "set_memory_serialize_page");
1165 Thread::muxRelease(&SerializePageLock);
1166 }
1167
1168 // Serialize all thread state variables
1169 void os::serialize_thread_states() {
1170 // On some platforms such as Solaris & Linux, the time duration of the page
1171 // permission restoration is observed to be much longer than expected due to
1172 // scheduler starvation problem etc. To avoid the long synchronization
1173 // time and expensive page trap spinning, 'SerializePageLock' is used to block
1174 // the mutator thread if such case is encountered. See bug 6546278 for details.
1175 Thread::muxAcquire(&SerializePageLock, "serialize_thread_states");
1176 os::protect_memory((char *)os::get_memory_serialize_page(),
1177 os::vm_page_size(), MEM_PROT_READ);
1178 os::protect_memory((char *)os::get_memory_serialize_page(),
1179 os::vm_page_size(), MEM_PROT_RW);
1180 Thread::muxRelease(&SerializePageLock);
1181 }
1182
1183 // Returns true if the current stack pointer is above the stack shadow
1184 // pages, false otherwise.
1185
1186 bool os::stack_shadow_pages_available(Thread *thread, methodHandle method) {
1187 assert(StackRedPages > 0 && StackYellowPages > 0,"Sanity check");
1188 address sp = current_stack_pointer();
1189 // Check if we have StackShadowPages above the yellow zone. This parameter
1190 // is dependent on the depth of the maximum VM call stack possible from
1191 // the handler for stack overflow. 'instanceof' in the stack overflow
1192 // handler or a println uses at least 8k stack of VM and native code
1193 // respectively.
1194 const int framesize_in_bytes =
1195 Interpreter::size_top_interpreter_activation(method()) * wordSize;
1196 int reserved_area = ((StackShadowPages + StackRedPages + StackYellowPages)
1197 * vm_page_size()) + framesize_in_bytes;
1198 // The very lower end of the stack
1199 address stack_limit = thread->stack_base() - thread->stack_size();
1200 return (sp > (stack_limit + reserved_area));
1201 }
1202
1203 size_t os::page_size_for_region(size_t region_min_size, size_t region_max_size,
1204 uint min_pages)
1205 {
1206 assert(min_pages > 0, "sanity");
1207 if (UseLargePages) {
1208 const size_t max_page_size = region_max_size / min_pages;
1209
1210 for (unsigned int i = 0; _page_sizes[i] != 0; ++i) {
1211 const size_t sz = _page_sizes[i];
1212 const size_t mask = sz - 1;
1213 if ((region_min_size & mask) == 0 && (region_max_size & mask) == 0) {
1214 // The largest page size with no fragmentation.
1215 return sz;
1216 }
1217
1218 if (sz <= max_page_size) {
1219 // The largest page size that satisfies the min_pages requirement.
1220 return sz;
1221 }
1222 }
1223 }
1224
1225 return vm_page_size();
1226 }
1227
1228 #ifndef PRODUCT
1229 void os::trace_page_sizes(const char* str, const size_t region_min_size,
1230 const size_t region_max_size, const size_t page_size,
1231 const char* base, const size_t size)
1232 {
1233 if (TracePageSizes) {
1234 tty->print_cr("%s: min=" SIZE_FORMAT " max=" SIZE_FORMAT
1235 " pg_sz=" SIZE_FORMAT " base=" PTR_FORMAT
1236 " size=" SIZE_FORMAT,
1237 str, region_min_size, region_max_size,
1238 page_size, base, size);
1239 }
1240 }
1241 #endif // #ifndef PRODUCT
1242
1243 // This is the working definition of a server class machine:
1244 // >= 2 physical CPU's and >=2GB of memory, with some fuzz
1245 // because the graphics memory (?) sometimes masks physical memory.
1246 // If you want to change the definition of a server class machine
1247 // on some OS or platform, e.g., >=4GB on Windohs platforms,
1248 // then you'll have to parameterize this method based on that state,
1249 // as was done for logical processors here, or replicate and
1250 // specialize this method for each platform. (Or fix os to have
1251 // some inheritance structure and use subclassing. Sigh.)
1252 // If you want some platform to always or never behave as a server
1253 // class machine, change the setting of AlwaysActAsServerClassMachine
1254 // and NeverActAsServerClassMachine in globals*.hpp.
1255 bool os::is_server_class_machine() {
1256 // First check for the early returns
1257 if (NeverActAsServerClassMachine) {
1258 return false;
1259 }
1260 if (AlwaysActAsServerClassMachine) {
1261 return true;
1262 }
1263 // Then actually look at the machine
1264 bool result = false;
1265 const unsigned int server_processors = 2;
1266 const julong server_memory = 2UL * G;
1267 // We seem not to get our full complement of memory.
1268 // We allow some part (1/8?) of the memory to be "missing",
1269 // based on the sizes of DIMMs, and maybe graphics cards.
1270 const julong missing_memory = 256UL * M;
1271
1272 /* Is this a server class machine? */
1273 if ((os::active_processor_count() >= (int)server_processors) &&
1274 (os::physical_memory() >= (server_memory - missing_memory))) {
1275 const unsigned int logical_processors =
1276 VM_Version::logical_processors_per_package();
1277 if (logical_processors > 1) {
1278 const unsigned int physical_packages =
1279 os::active_processor_count() / logical_processors;
1280 if (physical_packages > server_processors) {
1281 result = true;
1282 }
1283 } else {
1284 result = true;
1285 }
1286 }
1287 return result;
1288 }