jdk-sandbox: comparison hotspot/src/share/vm/runtime/os.cpp

equal deleted inserted replaced

-:fd16c54261b3
+:489c9b5090e2
+/*
+* Copyright 1997-2007 Sun Microsystems, Inc.  All Rights Reserved.
+* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+*
+* This code is free software; you can redistribute it and/or modify it
+* under the terms of the GNU General Public License version 2 only, as
+* published by the Free Software Foundation.
+*
+* This code is distributed in the hope that it will be useful, but WITHOUT
+* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+* version 2 for more details (a copy is included in the LICENSE file that
+* accompanied this code).
+*
+* You should have received a copy of the GNU General Public License version
+* 2 along with this work; if not, write to the Free Software Foundation,
+* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+*
+* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+* CA 95054 USA or visit www.sun.com if you need additional information or
+* have any questions.
+*
+*/
+# include "incls/_precompiled.incl"
+# include "incls/_os.cpp.incl"
+# include <signal.h>
+OSThread*         os::_starting_thread    = NULL;
+address           os::_polling_page       = NULL;
+volatile int32_t* os::_mem_serialize_page = NULL;
+uintptr_t         os::_serialize_page_mask = 0;
+long              os::_rand_seed          = 1;
+int               os::_processor_count    = 0;
+volatile jlong    os::_global_time        = 0;
+volatile int      os::_global_time_lock   = 0;
+bool              os::_use_global_time    = false;
+size_t            os::_page_sizes[os::page_sizes_max];
+#ifndef PRODUCT
+int os::num_mallocs = 0;            // # of calls to malloc/realloc
+size_t os::alloc_bytes = 0;         // # of bytes allocated
+int os::num_frees = 0;              // # of calls to free
+#endif
+// Atomic read of a jlong is assured by a seqlock; see update_global_time()
+jlong os::read_global_time() {
+#ifdef _LP64
+return _global_time;
+#else
+volatile int lock;
+volatile jlong current_time;
+int ctr = 0;
+for (;;) {
+lock = _global_time_lock;
+// spin while locked
+while ((lock & 0x1) != 0) {
+++ctr;
+if ((ctr & 0xFFF) == 0) {
+// Guarantee writer progress.  Can't use yield; yield is advisory
+// and has almost no effect on some platforms.  Don't need a state
+// transition - the park call will return promptly.
+assert(Thread::current() != NULL, "TLS not initialized");
+assert(Thread::current()->_ParkEvent != NULL, "sync not initialized");
+Thread::current()->_ParkEvent->park(1);
+}
+lock = _global_time_lock;
+}
+OrderAccess::loadload();
+current_time = _global_time;
+OrderAccess::loadload();
+// ratify seqlock value
+if (lock == _global_time_lock) {
+return current_time;
+}
+}
+#endif
+}
+//
+// NOTE - Assumes only one writer thread!
+//
+// We use a seqlock to guarantee that jlong _global_time is updated
+// atomically on 32-bit platforms.  A locked value is indicated by
+// the lock variable LSB == 1.  Readers will initially read the lock
+// value, spinning until the LSB == 0.  They then speculatively read
+// the global time value, then re-read the lock value to ensure that
+// it hasn't changed.  If the lock value has changed, the entire read
+// sequence is retried.
+//
+// Writers simply set the LSB = 1 (i.e. increment the variable),
+// update the global time, then release the lock and bump the version
+// number (i.e. increment the variable again.)  In this case we don't
+// even need a CAS since we ensure there's only one writer.
+//
+void os::update_global_time() {
+#ifdef _LP64
+_global_time = timeofday();
+#else
+assert((_global_time_lock & 0x1) == 0, "multiple writers?");
+jlong current_time = timeofday();
+_global_time_lock++; // lock
+OrderAccess::storestore();
+_global_time = current_time;
+OrderAccess::storestore();
+_global_time_lock++; // unlock
+#endif
+}
+// Fill in buffer with current local time as an ISO-8601 string.
+// E.g., yyyy-mm-ddThh:mm:ss-zzzz.
+// Returns buffer, or NULL if it failed.
+// This would mostly be a call to
+//     strftime(...., "%Y-%m-%d" "T" "%H:%M:%S" "%z", ....)
+// except that on Windows the %z behaves badly, so we do it ourselves.
+// Also, people wanted milliseconds on there,
+// and strftime doesn't do milliseconds.
+char* os::iso8601_time(char* buffer, size_t buffer_length) {
+// Output will be of the form "YYYY-MM-DDThh:mm:ss.mmm+zzzz\0"
+//                                      1         2
+//                             12345678901234567890123456789
+static const char* iso8601_format =
+"%04d-%02d-%02dT%02d:%02d:%02d.%03d%c%02d%02d";
+static const size_t needed_buffer = 29;
+// Sanity check the arguments
+if (buffer == NULL) {
+assert(false, "NULL buffer");
+return NULL;
+}
+if (buffer_length < needed_buffer) {
+assert(false, "buffer_length too small");
+return NULL;
+}
+// Get the current time
+jlong milliseconds_since_19700101 = timeofday();
+const int milliseconds_per_microsecond = 1000;
+const time_t seconds_since_19700101 =
+milliseconds_since_19700101 / milliseconds_per_microsecond;
+const int milliseconds_after_second =
+milliseconds_since_19700101 % milliseconds_per_microsecond;
+// Convert the time value to a tm and timezone variable
+const struct tm *time_struct_temp = localtime(&seconds_since_19700101);
+if (time_struct_temp == NULL) {
+assert(false, "Failed localtime");
+return NULL;
+}
+// Save the results of localtime
+const struct tm time_struct = *time_struct_temp;
+const time_t zone = timezone;
+// If daylight savings time is in effect,
+// we are 1 hour East of our time zone
+const time_t seconds_per_minute = 60;
+const time_t minutes_per_hour = 60;
+const time_t seconds_per_hour = seconds_per_minute * minutes_per_hour;
+time_t UTC_to_local = zone;
+if (time_struct.tm_isdst > 0) {
+UTC_to_local = UTC_to_local - seconds_per_hour;
+}
+// Compute the time zone offset.
+//    localtime(3C) sets timezone to the difference (in seconds)
+//    between UTC and and local time.
+//    ISO 8601 says we need the difference between local time and UTC,
+//    we change the sign of the localtime(3C) result.
+const time_t local_to_UTC = -(UTC_to_local);
+// Then we have to figure out if if we are ahead (+) or behind (-) UTC.
+char sign_local_to_UTC = '+';
+time_t abs_local_to_UTC = local_to_UTC;
+if (local_to_UTC < 0) {
+sign_local_to_UTC = '-';
+abs_local_to_UTC = -(abs_local_to_UTC);
+}
+// Convert time zone offset seconds to hours and minutes.
+const time_t zone_hours = (abs_local_to_UTC / seconds_per_hour);
+const time_t zone_min =
+((abs_local_to_UTC % seconds_per_hour) / seconds_per_minute);
+// Print an ISO 8601 date and time stamp into the buffer
+const int year = 1900 + time_struct.tm_year;
+const int month = 1 + time_struct.tm_mon;
+const int printed = jio_snprintf(buffer, buffer_length, iso8601_format,
+year,
+month,
+time_struct.tm_mday,
+time_struct.tm_hour,
+time_struct.tm_min,
+time_struct.tm_sec,
+milliseconds_after_second,
+sign_local_to_UTC,
+zone_hours,
+zone_min);
+if (printed == 0) {
+assert(false, "Failed jio_printf");
+return NULL;
+}
+return buffer;
+}
+OSReturn os::set_priority(Thread* thread, ThreadPriority p) {
+#ifdef ASSERT
+if (!(!thread->is_Java_thread() ||
+Thread::current() == thread  ||
+Threads_lock->owned_by_self()
+|| thread->is_Compiler_thread()
+)) {
+assert(false, "possibility of dangling Thread pointer");
+}
+#endif
+if (p >= MinPriority && p <= MaxPriority) {
+int priority = java_to_os_priority[p];
+return set_native_priority(thread, priority);
+} else {
+assert(false, "Should not happen");
+return OS_ERR;
+}
+}
+OSReturn os::get_priority(const Thread* const thread, ThreadPriority& priority) {
+int p;
+int os_prio;
+OSReturn ret = get_native_priority(thread, &os_prio);
+if (ret != OS_OK) return ret;
+for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] > os_prio; p--) ;
+priority = (ThreadPriority)p;
+return OS_OK;
+}
+// --------------------- sun.misc.Signal (optional) ---------------------
+// SIGBREAK is sent by the keyboard to query the VM state
+#ifndef SIGBREAK
+#define SIGBREAK SIGQUIT
+#endif
+// sigexitnum_pd is a platform-specific special signal used for terminating the Signal thread.
+static void signal_thread_entry(JavaThread* thread, TRAPS) {
+os::set_priority(thread, NearMaxPriority);
+while (true) {
+int sig;
+{
+// FIXME : Currently we have not decieded what should be the status
+//         for this java thread blocked here. Once we decide about
+//         that we should fix this.
+sig = os::signal_wait();
+}
+if (sig == os::sigexitnum_pd()) {
+// Terminate the signal thread
+return;
+}
+switch (sig) {
+case SIGBREAK: {
+// Check if the signal is a trigger to start the Attach Listener - in that
+// case don't print stack traces.
+if (!DisableAttachMechanism && AttachListener::is_init_trigger()) {
+continue;
+}
+// Print stack traces
+// Any SIGBREAK operations added here should make sure to flush
+// the output stream (e.g. tty->flush()) after output.  See 4803766.
+// Each module also prints an extra carriage return after its output.
+VM_PrintThreads op;
+VMThread::execute(&op);
+VM_PrintJNI jni_op;
+VMThread::execute(&jni_op);
+VM_FindDeadlocks op1(tty);
+VMThread::execute(&op1);
+Universe::print_heap_at_SIGBREAK();
+if (PrintClassHistogram) {
+VM_GC_HeapInspection op1(gclog_or_tty, true /* force full GC before heap inspection */);
+VMThread::execute(&op1);
+}
+if (JvmtiExport::should_post_data_dump()) {
+JvmtiExport::post_data_dump();
+}
+break;
+}
+default: {
+// Dispatch the signal to java
+HandleMark hm(THREAD);
+klassOop k = SystemDictionary::resolve_or_null(vmSymbolHandles::sun_misc_Signal(), THREAD);
+KlassHandle klass (THREAD, k);
+if (klass.not_null()) {
+JavaValue result(T_VOID);
+JavaCallArguments args;
+args.push_int(sig);
+JavaCalls::call_static(
+&result,
+klass,
+vmSymbolHandles::dispatch_name(),
+vmSymbolHandles::int_void_signature(),
+&args,
+THREAD
+);
+}
+if (HAS_PENDING_EXCEPTION) {
+// tty is initialized early so we don't expect it to be null, but
+// if it is we can't risk doing an initialization that might
+// trigger additional out-of-memory conditions
+if (tty != NULL) {
+char klass_name[256];
+char tmp_sig_name[16];
+const char* sig_name = "UNKNOWN";
+instanceKlass::cast(PENDING_EXCEPTION->klass())->
+name()->as_klass_external_name(klass_name, 256);
+if (os::exception_name(sig, tmp_sig_name, 16) != NULL)
+sig_name = tmp_sig_name;
+warning("Exception %s occurred dispatching signal %s to handler"
+"- the VM may need to be forcibly terminated",
+klass_name, sig_name );
+}
+CLEAR_PENDING_EXCEPTION;
+}
+}
+}
+}
+}
+void os::signal_init() {
+if (!ReduceSignalUsage) {
+// Setup JavaThread for processing signals
+EXCEPTION_MARK;
+klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK);
+instanceKlassHandle klass (THREAD, k);
+instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
+const char thread_name[] = "Signal Dispatcher";
+Handle string = java_lang_String::create_from_str(thread_name, CHECK);
+// Initialize thread_oop to put it into the system threadGroup
+Handle thread_group (THREAD, Universe::system_thread_group());
+JavaValue result(T_VOID);
+JavaCalls::call_special(&result, thread_oop,
+klass,
+vmSymbolHandles::object_initializer_name(),
+vmSymbolHandles::threadgroup_string_void_signature(),
+thread_group,
+string,
+CHECK);
+KlassHandle group(THREAD, SystemDictionary::threadGroup_klass());
+JavaCalls::call_special(&result,
+thread_group,
+group,
+vmSymbolHandles::add_method_name(),
+vmSymbolHandles::thread_void_signature(),
+thread_oop,         // ARG 1
+CHECK);
+os::signal_init_pd();
+{ MutexLocker mu(Threads_lock);
+JavaThread* signal_thread = new JavaThread(&signal_thread_entry);
+// At this point it may be possible that no osthread was created for the
+// JavaThread due to lack of memory. We would have to throw an exception
+// in that case. However, since this must work and we do not allow
+// exceptions anyway, check and abort if this fails.
+if (signal_thread == NULL || signal_thread->osthread() == NULL) {
+vm_exit_during_initialization("java.lang.OutOfMemoryError",
+"unable to create new native thread");
+}
+java_lang_Thread::set_thread(thread_oop(), signal_thread);
+java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);
+java_lang_Thread::set_daemon(thread_oop());
+signal_thread->set_threadObj(thread_oop());
+Threads::add(signal_thread);
+Thread::start(signal_thread);
+}
+// Handle ^BREAK
+os::signal(SIGBREAK, os::user_handler());
+}
+}
+void os::terminate_signal_thread() {
+if (!ReduceSignalUsage)
+signal_notify(sigexitnum_pd());
+}
+// --------------------- loading libraries ---------------------
+typedef jint (JNICALL *JNI_OnLoad_t)(JavaVM *, void *);
+extern struct JavaVM_ main_vm;
+static void* _native_java_library = NULL;
+void* os::native_java_library() {
+if (_native_java_library == NULL) {
+char buffer[JVM_MAXPATHLEN];
+char ebuf[1024];
+// Try to load verify dll first. In 1.3 java dll depends on it and is not always
+// able to find it when the loading executable is outside the JDK.
+// In order to keep working with 1.2 we ignore any loading errors.
+hpi::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), "verify");
+hpi::dll_load(buffer, ebuf, sizeof(ebuf));
+// Load java dll
+hpi::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), "java");
+_native_java_library = hpi::dll_load(buffer, ebuf, sizeof(ebuf));
+if (_native_java_library == NULL) {
+vm_exit_during_initialization("Unable to load native library", ebuf);
+}
+// The JNI_OnLoad handling is normally done by method load in java.lang.ClassLoader$NativeLibrary,
+// but the VM loads the base library explicitly so we have to check for JNI_OnLoad as well
+const char *onLoadSymbols[] = JNI_ONLOAD_SYMBOLS;
+JNI_OnLoad_t JNI_OnLoad = CAST_TO_FN_PTR(JNI_OnLoad_t, hpi::dll_lookup(_native_java_library, onLoadSymbols[0]));
+if (JNI_OnLoad != NULL) {
+JavaThread* thread = JavaThread::current();
+ThreadToNativeFromVM ttn(thread);
+HandleMark hm(thread);
+jint ver = (*JNI_OnLoad)(&main_vm, NULL);
+if (!Threads::is_supported_jni_version_including_1_1(ver)) {
+vm_exit_during_initialization("Unsupported JNI version");
+}
+}
+}
+return _native_java_library;
+}
+// --------------------- heap allocation utilities ---------------------
+char *os::strdup(const char *str) {
+size_t size = strlen(str);
+char *dup_str = (char *)malloc(size + 1);
+if (dup_str == NULL) return NULL;
+strcpy(dup_str, str);
+return dup_str;
+}
+#ifdef ASSERT
+#define space_before             (MallocCushion + sizeof(double))
+#define space_after              MallocCushion
+#define size_addr_from_base(p)   (size_t*)(p + space_before - sizeof(size_t))
+#define size_addr_from_obj(p)    ((size_t*)p - 1)
+// MallocCushion: size of extra cushion allocated around objects with +UseMallocOnly
+// NB: cannot be debug variable, because these aren't set from the command line until
+// *after* the first few allocs already happened
+#define MallocCushion            16
+#else
+#define space_before             0
+#define space_after              0
+#define size_addr_from_base(p)   should not use w/o ASSERT
+#define size_addr_from_obj(p)    should not use w/o ASSERT
+#define MallocCushion            0
+#endif
+#define paranoid                 0  /* only set to 1 if you suspect checking code has bug */
+#ifdef ASSERT
+inline size_t get_size(void* obj) {
+size_t size = *size_addr_from_obj(obj);
+if (size < 0 )
+fatal2("free: size field of object #%p was overwritten (%lu)", obj, size);
+return size;
+}
+u_char* find_cushion_backwards(u_char* start) {
+u_char* p = start;
+while (p[ 0] != badResourceValue || p[-1] != badResourceValue ||
+p[-2] != badResourceValue || p[-3] != badResourceValue) p--;
+// ok, we have four consecutive marker bytes; find start
+u_char* q = p - 4;
+while (*q == badResourceValue) q--;
+return q + 1;
+}
+u_char* find_cushion_forwards(u_char* start) {
+u_char* p = start;
+while (p[0] != badResourceValue || p[1] != badResourceValue ||
+p[2] != badResourceValue || p[3] != badResourceValue) p++;
+// ok, we have four consecutive marker bytes; find end of cushion
+u_char* q = p + 4;
+while (*q == badResourceValue) q++;
+return q - MallocCushion;
+}
+void print_neighbor_blocks(void* ptr) {
+// find block allocated before ptr (not entirely crash-proof)
+if (MallocCushion < 4) {
+tty->print_cr("### cannot find previous block (MallocCushion < 4)");
+return;
+}
+u_char* start_of_this_block = (u_char*)ptr - space_before;
+u_char* end_of_prev_block_data = start_of_this_block - space_after -1;
+// look for cushion in front of prev. block
+u_char* start_of_prev_block = find_cushion_backwards(end_of_prev_block_data);
+ptrdiff_t size = *size_addr_from_base(start_of_prev_block);
+u_char* obj = start_of_prev_block + space_before;
+if (size <= 0 ) {
+// start is bad; mayhave been confused by OS data inbetween objects
+// search one more backwards
+start_of_prev_block = find_cushion_backwards(start_of_prev_block);
+size = *size_addr_from_base(start_of_prev_block);
+obj = start_of_prev_block + space_before;
+}
+if (start_of_prev_block + space_before + size + space_after == start_of_this_block) {
+tty->print_cr("### previous object: %p (%ld bytes)", obj, size);
+} else {
+tty->print_cr("### previous object (not sure if correct): %p (%ld bytes)", obj, size);
+}
+// now find successor block
+u_char* start_of_next_block = (u_char*)ptr + *size_addr_from_obj(ptr) + space_after;
+start_of_next_block = find_cushion_forwards(start_of_next_block);
+u_char* next_obj = start_of_next_block + space_before;
+ptrdiff_t next_size = *size_addr_from_base(start_of_next_block);
+if (start_of_next_block[0] == badResourceValue &&
+start_of_next_block[1] == badResourceValue &&
+start_of_next_block[2] == badResourceValue &&
+start_of_next_block[3] == badResourceValue) {
+tty->print_cr("### next object: %p (%ld bytes)", next_obj, next_size);
+} else {
+tty->print_cr("### next object (not sure if correct): %p (%ld bytes)", next_obj, next_size);
+}
+}
+void report_heap_error(void* memblock, void* bad, const char* where) {
+tty->print_cr("## nof_mallocs = %d, nof_frees = %d", os::num_mallocs, os::num_frees);
+tty->print_cr("## memory stomp: byte at %p %s object %p", bad, where, memblock);
+print_neighbor_blocks(memblock);
+fatal("memory stomping error");
+}
+void verify_block(void* memblock) {
+size_t size = get_size(memblock);
+if (MallocCushion) {
+u_char* ptr = (u_char*)memblock - space_before;
+for (int i = 0; i < MallocCushion; i++) {
+if (ptr[i] != badResourceValue) {
+report_heap_error(memblock, ptr+i, "in front of");
+}
+}
+u_char* end = (u_char*)memblock + size + space_after;
+for (int j = -MallocCushion; j < 0; j++) {
+if (end[j] != badResourceValue) {
+report_heap_error(memblock, end+j, "after");
+}
+}
+}
+}
+#endif
+void* os::malloc(size_t size) {
+NOT_PRODUCT(num_mallocs++);
+NOT_PRODUCT(alloc_bytes += size);
+if (size == 0) {
+// return a valid pointer if size is zero
+// if NULL is returned the calling functions assume out of memory.
+size = 1;
+}
+NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
+u_char* ptr = (u_char*)::malloc(size + space_before + space_after);
+#ifdef ASSERT
+if (ptr == NULL) return NULL;
+if (MallocCushion) {
+for (u_char* p = ptr; p < ptr + MallocCushion; p++) *p = (u_char)badResourceValue;
+u_char* end = ptr + space_before + size;
+for (u_char* pq = ptr+MallocCushion; pq < end; pq++) *pq = (u_char)uninitBlockPad;
+for (u_char* q = end; q < end + MallocCushion; q++) *q = (u_char)badResourceValue;
+}
+// put size just before data
+*size_addr_from_base(ptr) = size;
+#endif
+u_char* memblock = ptr + space_before;
+if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
+tty->print_cr("os::malloc caught, %lu bytes --> %p", size, memblock);
+breakpoint();
+}
+debug_only(if (paranoid) verify_block(memblock));
+if (PrintMalloc && tty != NULL) tty->print_cr("os::malloc %lu bytes --> %p", size, memblock);
+return memblock;
+}
+void* os::realloc(void *memblock, size_t size) {
+NOT_PRODUCT(num_mallocs++);
+NOT_PRODUCT(alloc_bytes += size);
+#ifndef ASSERT
+return ::realloc(memblock, size);
+#else
+if (memblock == NULL) {
+return os::malloc(size);
+}
+if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
+tty->print_cr("os::realloc caught %p", memblock);
+breakpoint();
+}
+verify_block(memblock);
+NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
+if (size == 0) return NULL;
+// always move the block
+void* ptr = malloc(size);
+if (PrintMalloc) tty->print_cr("os::remalloc %lu bytes, %p --> %p", size, memblock, ptr);
+// Copy to new memory if malloc didn't fail
+if ( ptr != NULL ) {
+memcpy(ptr, memblock, MIN2(size, get_size(memblock)));
+if (paranoid) verify_block(ptr);
+if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) {
+tty->print_cr("os::realloc caught, %lu bytes --> %p", size, ptr);
+breakpoint();
+}
+free(memblock);
+}
+return ptr;
+#endif
+}
+void  os::free(void *memblock) {
+NOT_PRODUCT(num_frees++);
+#ifdef ASSERT
+if (memblock == NULL) return;
+if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
+if (tty != NULL) tty->print_cr("os::free caught %p", memblock);
+breakpoint();
+}
+verify_block(memblock);
+if (PrintMalloc && tty != NULL)
+// tty->print_cr("os::free %p", memblock);
+fprintf(stderr, "os::free %p\n", memblock);
+NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
+// Added by detlefs.
+if (MallocCushion) {
+u_char* ptr = (u_char*)memblock - space_before;
+for (u_char* p = ptr; p < ptr + MallocCushion; p++) {
+guarantee(*p == badResourceValue,
+"Thing freed should be malloc result.");
+*p = (u_char)freeBlockPad;
+}
+size_t size = get_size(memblock);
+u_char* end = ptr + space_before + size;
+for (u_char* q = end; q < end + MallocCushion; q++) {
+guarantee(*q == badResourceValue,
+"Thing freed should be malloc result.");
+*q = (u_char)freeBlockPad;
+}
+}
+#endif
+::free((char*)memblock - space_before);
+}
+void os::init_random(long initval) {
+_rand_seed = initval;
+}
+long os::random() {
+/* standard, well-known linear congruential random generator with
+* next_rand = (16807*seed) mod (2**31-1)
+* see
+* (1) "Random Number Generators: Good Ones Are Hard to Find",
+*      S.K. Park and K.W. Miller, Communications of the ACM 31:10 (Oct 1988),
+* (2) "Two Fast Implementations of the 'Minimal Standard' Random
+*     Number Generator", David G. Carta, Comm. ACM 33, 1 (Jan 1990), pp. 87-88.
+*/
+const long a = 16807;
+const unsigned long m = 2147483647;
+const long q = m / a;        assert(q == 127773, "weird math");
+const long r = m % a;        assert(r == 2836, "weird math");
+// compute az=2^31p+q
+unsigned long lo = a * (long)(_rand_seed & 0xFFFF);
+unsigned long hi = a * (long)((unsigned long)_rand_seed >> 16);
+lo += (hi & 0x7FFF) << 16;
+// if q overflowed, ignore the overflow and increment q
+if (lo > m) {
+lo &= m;
+++lo;
+}
+lo += hi >> 15;
+// if (p+q) overflowed, ignore the overflow and increment (p+q)
+if (lo > m) {
+lo &= m;
+++lo;
+}
+return (_rand_seed = lo);
+}
+// The INITIALIZED state is distinguished from the SUSPENDED state because the
+// conditions in which a thread is first started are different from those in which
+// a suspension is resumed.  These differences make it hard for us to apply the
+// tougher checks when starting threads that we want to do when resuming them.
+// However, when start_thread is called as a result of Thread.start, on a Java
+// thread, the operation is synchronized on the Java Thread object.  So there
+// cannot be a race to start the thread and hence for the thread to exit while
+// we are working on it.  Non-Java threads that start Java threads either have
+// to do so in a context in which races are impossible, or should do appropriate
+// locking.
+void os::start_thread(Thread* thread) {
+// guard suspend/resume
+MutexLockerEx ml(thread->SR_lock(), Mutex::_no_safepoint_check_flag);
+OSThread* osthread = thread->osthread();
+osthread->set_state(RUNNABLE);
+pd_start_thread(thread);
+}
+//---------------------------------------------------------------------------
+// Helper functions for fatal error handler
+void os::print_hex_dump(outputStream* st, address start, address end, int unitsize) {
+assert(unitsize == 1 || unitsize == 2 || unitsize == 4 || unitsize == 8, "just checking");
+int cols = 0;
+int cols_per_line = 0;
+switch (unitsize) {
+case 1: cols_per_line = 16; break;
+case 2: cols_per_line = 8;  break;
+case 4: cols_per_line = 4;  break;
+case 8: cols_per_line = 2;  break;
+default: return;
+}
+address p = start;
+st->print(PTR_FORMAT ":   ", start);
+while (p < end) {
+switch (unitsize) {
+case 1: st->print("%02x", *(u1*)p); break;
+case 2: st->print("%04x", *(u2*)p); break;
+case 4: st->print("%08x", *(u4*)p); break;
+case 8: st->print("%016" FORMAT64_MODIFIER "x", *(u8*)p); break;
+}
+p += unitsize;
+cols++;
+if (cols >= cols_per_line && p < end) {
+cols = 0;
+st->cr();
+st->print(PTR_FORMAT ":   ", p);
+} else {
+st->print(" ");
+}
+}
+st->cr();
+}
+void os::print_environment_variables(outputStream* st, const char** env_list,
+char* buffer, int len) {
+if (env_list) {
+st->print_cr("Environment Variables:");
+for (int i = 0; env_list[i] != NULL; i++) {
+if (getenv(env_list[i], buffer, len)) {
+st->print(env_list[i]);
+st->print("=");
+st->print_cr(buffer);
+}
+}
+}
+}
+void os::print_cpu_info(outputStream* st) {
+// cpu
+st->print("CPU:");
+st->print("total %d", os::processor_count());
+// It's not safe to query number of active processors after crash
+// st->print("(active %d)", os::active_processor_count());
+st->print(" %s", VM_Version::cpu_features());
+st->cr();
+}
+void os::print_date_and_time(outputStream *st) {
+time_t tloc;
+(void)time(&tloc);
+st->print("time: %s", ctime(&tloc));  // ctime adds newline.
+double t = os::elapsedTime();
+// NOTE: It tends to crash after a SEGV if we want to printf("%f",...) in
+//       Linux. Must be a bug in glibc ? Workaround is to round "t" to int
+//       before printf. We lost some precision, but who cares?
+st->print_cr("elapsed time: %d seconds", (int)t);
+}
+// Looks like all platforms except IA64 can use the same function to check
+// if C stack is walkable beyond current frame. The check for fp() is not
+// necessary on Sparc, but it's harmless.
+bool os::is_first_C_frame(frame* fr) {
+#ifdef IA64
+// In order to walk native frames on Itanium, we need to access the unwind
+// table, which is inside ELF. We don't want to parse ELF after fatal error,
+// so return true for IA64. If we need to support C stack walking on IA64,
+// this function needs to be moved to CPU specific files, as fp() on IA64
+// is register stack, which grows towards higher memory address.
+return true;
+#endif
+// Load up sp, fp, sender sp and sender fp, check for reasonable values.
+// Check usp first, because if that's bad the other accessors may fault
+// on some architectures.  Ditto ufp second, etc.
+uintptr_t fp_align_mask = (uintptr_t)(sizeof(address)-1);
+// sp on amd can be 32 bit aligned.
+uintptr_t sp_align_mask = (uintptr_t)(sizeof(int)-1);
+uintptr_t usp    = (uintptr_t)fr->sp();
+if ((usp & sp_align_mask) != 0) return true;
+uintptr_t ufp    = (uintptr_t)fr->fp();
+if ((ufp & fp_align_mask) != 0) return true;
+uintptr_t old_sp = (uintptr_t)fr->sender_sp();
+if ((old_sp & sp_align_mask) != 0) return true;
+if (old_sp == 0 || old_sp == (uintptr_t)-1) return true;
+uintptr_t old_fp = (uintptr_t)fr->link();
+if ((old_fp & fp_align_mask) != 0) return true;
+if (old_fp == 0 || old_fp == (uintptr_t)-1 || old_fp == ufp) return true;
+// stack grows downwards; if old_fp is below current fp or if the stack
+// frame is too large, either the stack is corrupted or fp is not saved
+// on stack (i.e. on x86, ebp may be used as general register). The stack
+// is not walkable beyond current frame.
+if (old_fp < ufp) return true;
+if (old_fp - ufp > 64 * K) return true;
+return false;
+}
+#ifdef ASSERT
+extern "C" void test_random() {
+const double m = 2147483647;
+double mean = 0.0, variance = 0.0, t;
+long reps = 10000;
+unsigned long seed = 1;
+tty->print_cr("seed %ld for %ld repeats...", seed, reps);
+os::init_random(seed);
+long num;
+for (int k = 0; k < reps; k++) {
+num = os::random();
+double u = (double)num / m;
+assert(u >= 0.0 && u <= 1.0, "bad random number!");
+// calculate mean and variance of the random sequence
+mean += u;
+variance += (u*u);
+}
+mean /= reps;
+variance /= (reps - 1);
+assert(num == 1043618065, "bad seed");
+tty->print_cr("mean of the 1st 10000 numbers: %f", mean);
+tty->print_cr("variance of the 1st 10000 numbers: %f", variance);
+const double eps = 0.0001;
+t = fabsd(mean - 0.5018);
+assert(t < eps, "bad mean");
+t = (variance - 0.3355) < 0.0 ? -(variance - 0.3355) : variance - 0.3355;
+assert(t < eps, "bad variance");
+}
+#endif
+// Set up the boot classpath.
+char* os::format_boot_path(const char* format_string,
+const char* home,
+int home_len,
+char fileSep,
+char pathSep) {
+assert((fileSep == '/' && pathSep == ':') ||
+(fileSep == '\\' && pathSep == ';'), "unexpected seperator chars");
+// Scan the format string to determine the length of the actual
+// boot classpath, and handle platform dependencies as well.
+int formatted_path_len = 0;
+const char* p;
+for (p = format_string; *p != 0; ++p) {
+if (*p == '%') formatted_path_len += home_len - 1;
+++formatted_path_len;
+}
+char* formatted_path = NEW_C_HEAP_ARRAY(char, formatted_path_len + 1);
+if (formatted_path == NULL) {
+return NULL;
+}
+// Create boot classpath from format, substituting separator chars and
+// java home directory.
+char* q = formatted_path;
+for (p = format_string; *p != 0; ++p) {
+switch (*p) {
+case '%':
+strcpy(q, home);
+q += home_len;
+break;
+case '/':
+*q++ = fileSep;
+break;
+case ':':
+*q++ = pathSep;
+break;
+default:
+*q++ = *p;
+}
+}
+*q = '\0';
+assert((q - formatted_path) == formatted_path_len, "formatted_path size botched");
+return formatted_path;
+}
+bool os::set_boot_path(char fileSep, char pathSep) {
+const char* home = Arguments::get_java_home();
+int home_len = (int)strlen(home);
+static const char* meta_index_dir_format = "%/lib/";
+static const char* meta_index_format = "%/lib/meta-index";
+char* meta_index = format_boot_path(meta_index_format, home, home_len, fileSep, pathSep);
+if (meta_index == NULL) return false;
+char* meta_index_dir = format_boot_path(meta_index_dir_format, home, home_len, fileSep, pathSep);
+if (meta_index_dir == NULL) return false;
+Arguments::set_meta_index_path(meta_index, meta_index_dir);
+// Any modification to the JAR-file list, for the boot classpath must be
+// aligned with install/install/make/common/Pack.gmk. Note: boot class
+// path class JARs, are stripped for StackMapTable to reduce download size.
+static const char classpath_format[] =
+"%/lib/resources.jar:"
+"%/lib/rt.jar:"
+"%/lib/sunrsasign.jar:"
+"%/lib/jsse.jar:"
+"%/lib/jce.jar:"
+"%/lib/charsets.jar:"
+"%/classes";
+char* sysclasspath = format_boot_path(classpath_format, home, home_len, fileSep, pathSep);
+if (sysclasspath == NULL) return false;
+Arguments::set_sysclasspath(sysclasspath);
+return true;
+}
+void os::set_memory_serialize_page(address page) {
+int count = log2_intptr(sizeof(class JavaThread)) - log2_intptr(64);
+_mem_serialize_page = (volatile int32_t *)page;
+// We initialize the serialization page shift count here
+// We assume a cache line size of 64 bytes
+assert(SerializePageShiftCount == count,
+"thread size changed, fix SerializePageShiftCount constant");
+set_serialize_page_mask((uintptr_t)(vm_page_size() - sizeof(int32_t)));
+}
+// This method is called from signal handler when SIGSEGV occurs while the current
+// thread tries to store to the "read-only" memory serialize page during state
+// transition.
+void os::block_on_serialize_page_trap() {
+if (TraceSafepoint) {
+tty->print_cr("Block until the serialize page permission restored");
+}
+// When VMThread is holding the SerializePage_lock during modifying the
+// access permission of the memory serialize page, the following call
+// will block until the permission of that page is restored to rw.
+// Generally, it is unsafe to manipulate locks in signal handlers, but in
+// this case, it's OK as the signal is synchronous and we know precisely when
+// it can occur. SerializePage_lock is a transiently-held leaf lock, so
+// lock_without_safepoint_check should be safe.
+SerializePage_lock->lock_without_safepoint_check();
+SerializePage_lock->unlock();
+}
+// Serialize all thread state variables
+void os::serialize_thread_states() {
+// On some platforms such as Solaris & Linux, the time duration of the page
+// permission restoration is observed to be much longer than expected  due to
+// scheduler starvation problem etc. To avoid the long synchronization
+// time and expensive page trap spinning, 'SerializePage_lock' is used to block
+// the mutator thread if such case is encountered. Since this method is always
+// called by VMThread during safepoint, lock_without_safepoint_check is used
+// instead. See bug 6546278.
+SerializePage_lock->lock_without_safepoint_check();
+os::protect_memory( (char *)os::get_memory_serialize_page(), os::vm_page_size() );
+os::unguard_memory( (char *)os::get_memory_serialize_page(), os::vm_page_size() );
+SerializePage_lock->unlock();
+}
+// Returns true if the current stack pointer is above the stack shadow
+// pages, false otherwise.
+bool os::stack_shadow_pages_available(Thread *thread, methodHandle method) {
+assert(StackRedPages > 0 && StackYellowPages > 0,"Sanity check");
+address sp = current_stack_pointer();
+// Check if we have StackShadowPages above the yellow zone.  This parameter
+// is dependant on the depth of the maximum VM call stack possible from
+// the handler for stack overflow.  'instanceof' in the stack overflow
+// handler or a println uses at least 8k stack of VM and native code
+// respectively.
+const int framesize_in_bytes =
+Interpreter::size_top_interpreter_activation(method()) * wordSize;
+int reserved_area = ((StackShadowPages + StackRedPages + StackYellowPages)
+* vm_page_size()) + framesize_in_bytes;
+// The very lower end of the stack
+address stack_limit = thread->stack_base() - thread->stack_size();
+return (sp > (stack_limit + reserved_area));
+}
+size_t os::page_size_for_region(size_t region_min_size, size_t region_max_size,
+uint min_pages)
+{
+assert(min_pages > 0, "sanity");
+if (UseLargePages) {
+const size_t max_page_size = region_max_size / min_pages;
+for (unsigned int i = 0; _page_sizes[i] != 0; ++i) {
+const size_t sz = _page_sizes[i];
+const size_t mask = sz - 1;
+if ((region_min_size & mask) == 0 && (region_max_size & mask) == 0) {
+// The largest page size with no fragmentation.
+return sz;
+}
+if (sz <= max_page_size) {
+// The largest page size that satisfies the min_pages requirement.
+return sz;
+}
+}
+}
+return vm_page_size();
+}
+#ifndef PRODUCT
+void os::trace_page_sizes(const char* str, const size_t region_min_size,
+const size_t region_max_size, const size_t page_size,
+const char* base, const size_t size)
+{
+if (TracePageSizes) {
+tty->print_cr("%s:  min=" SIZE_FORMAT " max=" SIZE_FORMAT
+" pg_sz=" SIZE_FORMAT " base=" PTR_FORMAT
+" size=" SIZE_FORMAT,
+str, region_min_size, region_max_size,
+page_size, base, size);
+}
+}
+#endif  // #ifndef PRODUCT
+// This is the working definition of a server class machine:
+// >= 2 physical CPU's and >=2GB of memory, with some fuzz
+// because the graphics memory (?) sometimes masks physical memory.
+// If you want to change the definition of a server class machine
+// on some OS or platform, e.g., >=4GB on Windohs platforms,
+// then you'll have to parameterize this method based on that state,
+// as was done for logical processors here, or replicate and
+// specialize this method for each platform.  (Or fix os to have
+// some inheritance structure and use subclassing.  Sigh.)
+// If you want some platform to always or never behave as a server
+// class machine, change the setting of AlwaysActAsServerClassMachine
+// and NeverActAsServerClassMachine in globals*.hpp.
+bool os::is_server_class_machine() {
+// First check for the early returns
+if (NeverActAsServerClassMachine) {
+return false;
+}
+if (AlwaysActAsServerClassMachine) {
+return true;
+}
+// Then actually look at the machine
+bool         result            = false;
+const unsigned int    server_processors = 2;
+const julong server_memory     = 2UL * G;
+// We seem not to get our full complement of memory.
+//     We allow some part (1/8?) of the memory to be "missing",
+//     based on the sizes of DIMMs, and maybe graphics cards.
+const julong missing_memory   = 256UL * M;
+/* Is this a server class machine? */
+if ((os::active_processor_count() >= (int)server_processors) &&
+(os::physical_memory() >= (server_memory - missing_memory))) {
+const unsigned int logical_processors =
+VM_Version::logical_processors_per_package();
+if (logical_processors > 1) {
+const unsigned int physical_packages =
+os::active_processor_count() / logical_processors;
+if (physical_packages > server_processors) {
+result = true;
+}
+} else {
+result = true;
+}
+}
+return result;
+}

changeset 1	489c9b5090e2
child 228	69939fa91efd