Mercurial > hg > graal-jvmci-8
diff src/share/vm/runtime/os.cpp @ 0:a61af66fc99e jdk7-b24
Initial load
author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | 2a8eb116ebbe |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/runtime/os.cpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,1108 @@ +/* + * 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; +}