duke@435: /*
xdono@631:  * Copyright 1997-2008 Sun Microsystems, Inc.  All Rights Reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
duke@435:  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435:  * CA 95054 USA or visit www.sun.com if you need additional information or
duke@435:  * have any questions.
duke@435:  *
duke@435:  */
duke@435: 
duke@435: # include "incls/_precompiled.incl"
duke@435: # include "incls/_os.cpp.incl"
duke@435: 
duke@435: # include <signal.h>
duke@435: 
duke@435: OSThread*         os::_starting_thread    = NULL;
duke@435: address           os::_polling_page       = NULL;
duke@435: volatile int32_t* os::_mem_serialize_page = NULL;
duke@435: uintptr_t         os::_serialize_page_mask = 0;
duke@435: long              os::_rand_seed          = 1;
duke@435: int               os::_processor_count    = 0;
duke@435: size_t            os::_page_sizes[os::page_sizes_max];
duke@435: 
duke@435: #ifndef PRODUCT
duke@435: int os::num_mallocs = 0;            // # of calls to malloc/realloc
duke@435: size_t os::alloc_bytes = 0;         // # of bytes allocated
duke@435: int os::num_frees = 0;              // # of calls to free
duke@435: #endif
duke@435: 
duke@435: // Fill in buffer with current local time as an ISO-8601 string.
duke@435: // E.g., yyyy-mm-ddThh:mm:ss-zzzz.
duke@435: // Returns buffer, or NULL if it failed.
duke@435: // This would mostly be a call to
duke@435: //     strftime(...., "%Y-%m-%d" "T" "%H:%M:%S" "%z", ....)
duke@435: // except that on Windows the %z behaves badly, so we do it ourselves.
duke@435: // Also, people wanted milliseconds on there,
duke@435: // and strftime doesn't do milliseconds.
duke@435: char* os::iso8601_time(char* buffer, size_t buffer_length) {
duke@435:   // Output will be of the form "YYYY-MM-DDThh:mm:ss.mmm+zzzz\0"
duke@435:   //                                      1         2
duke@435:   //                             12345678901234567890123456789
duke@435:   static const char* iso8601_format =
duke@435:     "%04d-%02d-%02dT%02d:%02d:%02d.%03d%c%02d%02d";
duke@435:   static const size_t needed_buffer = 29;
duke@435: 
duke@435:   // Sanity check the arguments
duke@435:   if (buffer == NULL) {
duke@435:     assert(false, "NULL buffer");
duke@435:     return NULL;
duke@435:   }
duke@435:   if (buffer_length < needed_buffer) {
duke@435:     assert(false, "buffer_length too small");
duke@435:     return NULL;
duke@435:   }
duke@435:   // Get the current time
sbohne@496:   jlong milliseconds_since_19700101 = javaTimeMillis();
duke@435:   const int milliseconds_per_microsecond = 1000;
duke@435:   const time_t seconds_since_19700101 =
duke@435:     milliseconds_since_19700101 / milliseconds_per_microsecond;
duke@435:   const int milliseconds_after_second =
duke@435:     milliseconds_since_19700101 % milliseconds_per_microsecond;
duke@435:   // Convert the time value to a tm and timezone variable
duke@435:   const struct tm *time_struct_temp = localtime(&seconds_since_19700101);
duke@435:   if (time_struct_temp == NULL) {
duke@435:     assert(false, "Failed localtime");
duke@435:     return NULL;
duke@435:   }
duke@435:   // Save the results of localtime
duke@435:   const struct tm time_struct = *time_struct_temp;
duke@435:   const time_t zone = timezone;
duke@435: 
duke@435:   // If daylight savings time is in effect,
duke@435:   // we are 1 hour East of our time zone
duke@435:   const time_t seconds_per_minute = 60;
duke@435:   const time_t minutes_per_hour = 60;
duke@435:   const time_t seconds_per_hour = seconds_per_minute * minutes_per_hour;
duke@435:   time_t UTC_to_local = zone;
duke@435:   if (time_struct.tm_isdst > 0) {
duke@435:     UTC_to_local = UTC_to_local - seconds_per_hour;
duke@435:   }
duke@435:   // Compute the time zone offset.
duke@435:   //    localtime(3C) sets timezone to the difference (in seconds)
duke@435:   //    between UTC and and local time.
duke@435:   //    ISO 8601 says we need the difference between local time and UTC,
duke@435:   //    we change the sign of the localtime(3C) result.
duke@435:   const time_t local_to_UTC = -(UTC_to_local);
duke@435:   // Then we have to figure out if if we are ahead (+) or behind (-) UTC.
duke@435:   char sign_local_to_UTC = '+';
duke@435:   time_t abs_local_to_UTC = local_to_UTC;
duke@435:   if (local_to_UTC < 0) {
duke@435:     sign_local_to_UTC = '-';
duke@435:     abs_local_to_UTC = -(abs_local_to_UTC);
duke@435:   }
duke@435:   // Convert time zone offset seconds to hours and minutes.
duke@435:   const time_t zone_hours = (abs_local_to_UTC / seconds_per_hour);
duke@435:   const time_t zone_min =
duke@435:     ((abs_local_to_UTC % seconds_per_hour) / seconds_per_minute);
duke@435: 
duke@435:   // Print an ISO 8601 date and time stamp into the buffer
duke@435:   const int year = 1900 + time_struct.tm_year;
duke@435:   const int month = 1 + time_struct.tm_mon;
duke@435:   const int printed = jio_snprintf(buffer, buffer_length, iso8601_format,
duke@435:                                    year,
duke@435:                                    month,
duke@435:                                    time_struct.tm_mday,
duke@435:                                    time_struct.tm_hour,
duke@435:                                    time_struct.tm_min,
duke@435:                                    time_struct.tm_sec,
duke@435:                                    milliseconds_after_second,
duke@435:                                    sign_local_to_UTC,
duke@435:                                    zone_hours,
duke@435:                                    zone_min);
duke@435:   if (printed == 0) {
duke@435:     assert(false, "Failed jio_printf");
duke@435:     return NULL;
duke@435:   }
duke@435:   return buffer;
duke@435: }
duke@435: 
duke@435: OSReturn os::set_priority(Thread* thread, ThreadPriority p) {
duke@435: #ifdef ASSERT
duke@435:   if (!(!thread->is_Java_thread() ||
duke@435:          Thread::current() == thread  ||
duke@435:          Threads_lock->owned_by_self()
duke@435:          || thread->is_Compiler_thread()
duke@435:         )) {
duke@435:     assert(false, "possibility of dangling Thread pointer");
duke@435:   }
duke@435: #endif
duke@435: 
duke@435:   if (p >= MinPriority && p <= MaxPriority) {
duke@435:     int priority = java_to_os_priority[p];
duke@435:     return set_native_priority(thread, priority);
duke@435:   } else {
duke@435:     assert(false, "Should not happen");
duke@435:     return OS_ERR;
duke@435:   }
duke@435: }
duke@435: 
duke@435: 
duke@435: OSReturn os::get_priority(const Thread* const thread, ThreadPriority& priority) {
duke@435:   int p;
duke@435:   int os_prio;
duke@435:   OSReturn ret = get_native_priority(thread, &os_prio);
duke@435:   if (ret != OS_OK) return ret;
duke@435: 
duke@435:   for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] > os_prio; p--) ;
duke@435:   priority = (ThreadPriority)p;
duke@435:   return OS_OK;
duke@435: }
duke@435: 
duke@435: 
duke@435: // --------------------- sun.misc.Signal (optional) ---------------------
duke@435: 
duke@435: 
duke@435: // SIGBREAK is sent by the keyboard to query the VM state
duke@435: #ifndef SIGBREAK
duke@435: #define SIGBREAK SIGQUIT
duke@435: #endif
duke@435: 
duke@435: // sigexitnum_pd is a platform-specific special signal used for terminating the Signal thread.
duke@435: 
duke@435: 
duke@435: static void signal_thread_entry(JavaThread* thread, TRAPS) {
duke@435:   os::set_priority(thread, NearMaxPriority);
duke@435:   while (true) {
duke@435:     int sig;
duke@435:     {
duke@435:       // FIXME : Currently we have not decieded what should be the status
duke@435:       //         for this java thread blocked here. Once we decide about
duke@435:       //         that we should fix this.
duke@435:       sig = os::signal_wait();
duke@435:     }
duke@435:     if (sig == os::sigexitnum_pd()) {
duke@435:        // Terminate the signal thread
duke@435:        return;
duke@435:     }
duke@435: 
duke@435:     switch (sig) {
duke@435:       case SIGBREAK: {
duke@435:         // Check if the signal is a trigger to start the Attach Listener - in that
duke@435:         // case don't print stack traces.
duke@435:         if (!DisableAttachMechanism && AttachListener::is_init_trigger()) {
duke@435:           continue;
duke@435:         }
duke@435:         // Print stack traces
duke@435:         // Any SIGBREAK operations added here should make sure to flush
duke@435:         // the output stream (e.g. tty->flush()) after output.  See 4803766.
duke@435:         // Each module also prints an extra carriage return after its output.
duke@435:         VM_PrintThreads op;
duke@435:         VMThread::execute(&op);
duke@435:         VM_PrintJNI jni_op;
duke@435:         VMThread::execute(&jni_op);
duke@435:         VM_FindDeadlocks op1(tty);
duke@435:         VMThread::execute(&op1);
duke@435:         Universe::print_heap_at_SIGBREAK();
duke@435:         if (PrintClassHistogram) {
duke@435:           VM_GC_HeapInspection op1(gclog_or_tty, true /* force full GC before heap inspection */);
duke@435:           VMThread::execute(&op1);
duke@435:         }
duke@435:         if (JvmtiExport::should_post_data_dump()) {
duke@435:           JvmtiExport::post_data_dump();
duke@435:         }
duke@435:         break;
duke@435:       }
duke@435:       default: {
duke@435:         // Dispatch the signal to java
duke@435:         HandleMark hm(THREAD);
duke@435:         klassOop k = SystemDictionary::resolve_or_null(vmSymbolHandles::sun_misc_Signal(), THREAD);
duke@435:         KlassHandle klass (THREAD, k);
duke@435:         if (klass.not_null()) {
duke@435:           JavaValue result(T_VOID);
duke@435:           JavaCallArguments args;
duke@435:           args.push_int(sig);
duke@435:           JavaCalls::call_static(
duke@435:             &result,
duke@435:             klass,
duke@435:             vmSymbolHandles::dispatch_name(),
duke@435:             vmSymbolHandles::int_void_signature(),
duke@435:             &args,
duke@435:             THREAD
duke@435:           );
duke@435:         }
duke@435:         if (HAS_PENDING_EXCEPTION) {
duke@435:           // tty is initialized early so we don't expect it to be null, but
duke@435:           // if it is we can't risk doing an initialization that might
duke@435:           // trigger additional out-of-memory conditions
duke@435:           if (tty != NULL) {
duke@435:             char klass_name[256];
duke@435:             char tmp_sig_name[16];
duke@435:             const char* sig_name = "UNKNOWN";
duke@435:             instanceKlass::cast(PENDING_EXCEPTION->klass())->
duke@435:               name()->as_klass_external_name(klass_name, 256);
duke@435:             if (os::exception_name(sig, tmp_sig_name, 16) != NULL)
duke@435:               sig_name = tmp_sig_name;
duke@435:             warning("Exception %s occurred dispatching signal %s to handler"
duke@435:                     "- the VM may need to be forcibly terminated",
duke@435:                     klass_name, sig_name );
duke@435:           }
duke@435:           CLEAR_PENDING_EXCEPTION;
duke@435:         }
duke@435:       }
duke@435:     }
duke@435:   }
duke@435: }
duke@435: 
duke@435: 
duke@435: void os::signal_init() {
duke@435:   if (!ReduceSignalUsage) {
duke@435:     // Setup JavaThread for processing signals
duke@435:     EXCEPTION_MARK;
duke@435:     klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK);
duke@435:     instanceKlassHandle klass (THREAD, k);
duke@435:     instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
duke@435: 
duke@435:     const char thread_name[] = "Signal Dispatcher";
duke@435:     Handle string = java_lang_String::create_from_str(thread_name, CHECK);
duke@435: 
duke@435:     // Initialize thread_oop to put it into the system threadGroup
duke@435:     Handle thread_group (THREAD, Universe::system_thread_group());
duke@435:     JavaValue result(T_VOID);
duke@435:     JavaCalls::call_special(&result, thread_oop,
duke@435:                            klass,
duke@435:                            vmSymbolHandles::object_initializer_name(),
duke@435:                            vmSymbolHandles::threadgroup_string_void_signature(),
duke@435:                            thread_group,
duke@435:                            string,
duke@435:                            CHECK);
duke@435: 
duke@435:     KlassHandle group(THREAD, SystemDictionary::threadGroup_klass());
duke@435:     JavaCalls::call_special(&result,
duke@435:                             thread_group,
duke@435:                             group,
duke@435:                             vmSymbolHandles::add_method_name(),
duke@435:                             vmSymbolHandles::thread_void_signature(),
duke@435:                             thread_oop,         // ARG 1
duke@435:                             CHECK);
duke@435: 
duke@435:     os::signal_init_pd();
duke@435: 
duke@435:     { MutexLocker mu(Threads_lock);
duke@435:       JavaThread* signal_thread = new JavaThread(&signal_thread_entry);
duke@435: 
duke@435:       // At this point it may be possible that no osthread was created for the
duke@435:       // JavaThread due to lack of memory. We would have to throw an exception
duke@435:       // in that case. However, since this must work and we do not allow
duke@435:       // exceptions anyway, check and abort if this fails.
duke@435:       if (signal_thread == NULL || signal_thread->osthread() == NULL) {
duke@435:         vm_exit_during_initialization("java.lang.OutOfMemoryError",
duke@435:                                       "unable to create new native thread");
duke@435:       }
duke@435: 
duke@435:       java_lang_Thread::set_thread(thread_oop(), signal_thread);
duke@435:       java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);
duke@435:       java_lang_Thread::set_daemon(thread_oop());
duke@435: 
duke@435:       signal_thread->set_threadObj(thread_oop());
duke@435:       Threads::add(signal_thread);
duke@435:       Thread::start(signal_thread);
duke@435:     }
duke@435:     // Handle ^BREAK
duke@435:     os::signal(SIGBREAK, os::user_handler());
duke@435:   }
duke@435: }
duke@435: 
duke@435: 
duke@435: void os::terminate_signal_thread() {
duke@435:   if (!ReduceSignalUsage)
duke@435:     signal_notify(sigexitnum_pd());
duke@435: }
duke@435: 
duke@435: 
duke@435: // --------------------- loading libraries ---------------------
duke@435: 
duke@435: typedef jint (JNICALL *JNI_OnLoad_t)(JavaVM *, void *);
duke@435: extern struct JavaVM_ main_vm;
duke@435: 
duke@435: static void* _native_java_library = NULL;
duke@435: 
duke@435: void* os::native_java_library() {
duke@435:   if (_native_java_library == NULL) {
duke@435:     char buffer[JVM_MAXPATHLEN];
duke@435:     char ebuf[1024];
duke@435: 
duke@435:     // Try to load verify dll first. In 1.3 java dll depends on it and is not always
duke@435:     // able to find it when the loading executable is outside the JDK.
duke@435:     // In order to keep working with 1.2 we ignore any loading errors.
duke@435:     hpi::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), "verify");
duke@435:     hpi::dll_load(buffer, ebuf, sizeof(ebuf));
duke@435: 
duke@435:     // Load java dll
duke@435:     hpi::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), "java");
duke@435:     _native_java_library = hpi::dll_load(buffer, ebuf, sizeof(ebuf));
duke@435:     if (_native_java_library == NULL) {
duke@435:       vm_exit_during_initialization("Unable to load native library", ebuf);
duke@435:     }
duke@435:     // The JNI_OnLoad handling is normally done by method load in java.lang.ClassLoader$NativeLibrary,
duke@435:     // but the VM loads the base library explicitly so we have to check for JNI_OnLoad as well
duke@435:     const char *onLoadSymbols[] = JNI_ONLOAD_SYMBOLS;
duke@435:     JNI_OnLoad_t JNI_OnLoad = CAST_TO_FN_PTR(JNI_OnLoad_t, hpi::dll_lookup(_native_java_library, onLoadSymbols[0]));
duke@435:     if (JNI_OnLoad != NULL) {
duke@435:       JavaThread* thread = JavaThread::current();
duke@435:       ThreadToNativeFromVM ttn(thread);
duke@435:       HandleMark hm(thread);
duke@435:       jint ver = (*JNI_OnLoad)(&main_vm, NULL);
duke@435:       if (!Threads::is_supported_jni_version_including_1_1(ver)) {
duke@435:         vm_exit_during_initialization("Unsupported JNI version");
duke@435:       }
duke@435:     }
duke@435:   }
duke@435:   return _native_java_library;
duke@435: }
duke@435: 
duke@435: // --------------------- heap allocation utilities ---------------------
duke@435: 
duke@435: char *os::strdup(const char *str) {
duke@435:   size_t size = strlen(str);
duke@435:   char *dup_str = (char *)malloc(size + 1);
duke@435:   if (dup_str == NULL) return NULL;
duke@435:   strcpy(dup_str, str);
duke@435:   return dup_str;
duke@435: }
duke@435: 
duke@435: 
duke@435: 
duke@435: #ifdef ASSERT
duke@435: #define space_before             (MallocCushion + sizeof(double))
duke@435: #define space_after              MallocCushion
duke@435: #define size_addr_from_base(p)   (size_t*)(p + space_before - sizeof(size_t))
duke@435: #define size_addr_from_obj(p)    ((size_t*)p - 1)
duke@435: // MallocCushion: size of extra cushion allocated around objects with +UseMallocOnly
duke@435: // NB: cannot be debug variable, because these aren't set from the command line until
duke@435: // *after* the first few allocs already happened
duke@435: #define MallocCushion            16
duke@435: #else
duke@435: #define space_before             0
duke@435: #define space_after              0
duke@435: #define size_addr_from_base(p)   should not use w/o ASSERT
duke@435: #define size_addr_from_obj(p)    should not use w/o ASSERT
duke@435: #define MallocCushion            0
duke@435: #endif
duke@435: #define paranoid                 0  /* only set to 1 if you suspect checking code has bug */
duke@435: 
duke@435: #ifdef ASSERT
duke@435: inline size_t get_size(void* obj) {
duke@435:   size_t size = *size_addr_from_obj(obj);
duke@435:   if (size < 0 )
duke@435:     fatal2("free: size field of object #%p was overwritten (%lu)", obj, size);
duke@435:   return size;
duke@435: }
duke@435: 
duke@435: u_char* find_cushion_backwards(u_char* start) {
duke@435:   u_char* p = start;
duke@435:   while (p[ 0] != badResourceValue || p[-1] != badResourceValue ||
duke@435:          p[-2] != badResourceValue || p[-3] != badResourceValue) p--;
duke@435:   // ok, we have four consecutive marker bytes; find start
duke@435:   u_char* q = p - 4;
duke@435:   while (*q == badResourceValue) q--;
duke@435:   return q + 1;
duke@435: }
duke@435: 
duke@435: u_char* find_cushion_forwards(u_char* start) {
duke@435:   u_char* p = start;
duke@435:   while (p[0] != badResourceValue || p[1] != badResourceValue ||
duke@435:          p[2] != badResourceValue || p[3] != badResourceValue) p++;
duke@435:   // ok, we have four consecutive marker bytes; find end of cushion
duke@435:   u_char* q = p + 4;
duke@435:   while (*q == badResourceValue) q++;
duke@435:   return q - MallocCushion;
duke@435: }
duke@435: 
duke@435: void print_neighbor_blocks(void* ptr) {
duke@435:   // find block allocated before ptr (not entirely crash-proof)
duke@435:   if (MallocCushion < 4) {
duke@435:     tty->print_cr("### cannot find previous block (MallocCushion < 4)");
duke@435:     return;
duke@435:   }
duke@435:   u_char* start_of_this_block = (u_char*)ptr - space_before;
duke@435:   u_char* end_of_prev_block_data = start_of_this_block - space_after -1;
duke@435:   // look for cushion in front of prev. block
duke@435:   u_char* start_of_prev_block = find_cushion_backwards(end_of_prev_block_data);
duke@435:   ptrdiff_t size = *size_addr_from_base(start_of_prev_block);
duke@435:   u_char* obj = start_of_prev_block + space_before;
duke@435:   if (size <= 0 ) {
duke@435:     // start is bad; mayhave been confused by OS data inbetween objects
duke@435:     // search one more backwards
duke@435:     start_of_prev_block = find_cushion_backwards(start_of_prev_block);
duke@435:     size = *size_addr_from_base(start_of_prev_block);
duke@435:     obj = start_of_prev_block + space_before;
duke@435:   }
duke@435: 
duke@435:   if (start_of_prev_block + space_before + size + space_after == start_of_this_block) {
duke@435:     tty->print_cr("### previous object: %p (%ld bytes)", obj, size);
duke@435:   } else {
duke@435:     tty->print_cr("### previous object (not sure if correct): %p (%ld bytes)", obj, size);
duke@435:   }
duke@435: 
duke@435:   // now find successor block
duke@435:   u_char* start_of_next_block = (u_char*)ptr + *size_addr_from_obj(ptr) + space_after;
duke@435:   start_of_next_block = find_cushion_forwards(start_of_next_block);
duke@435:   u_char* next_obj = start_of_next_block + space_before;
duke@435:   ptrdiff_t next_size = *size_addr_from_base(start_of_next_block);
duke@435:   if (start_of_next_block[0] == badResourceValue &&
duke@435:       start_of_next_block[1] == badResourceValue &&
duke@435:       start_of_next_block[2] == badResourceValue &&
duke@435:       start_of_next_block[3] == badResourceValue) {
duke@435:     tty->print_cr("### next object: %p (%ld bytes)", next_obj, next_size);
duke@435:   } else {
duke@435:     tty->print_cr("### next object (not sure if correct): %p (%ld bytes)", next_obj, next_size);
duke@435:   }
duke@435: }
duke@435: 
duke@435: 
duke@435: void report_heap_error(void* memblock, void* bad, const char* where) {
duke@435:   tty->print_cr("## nof_mallocs = %d, nof_frees = %d", os::num_mallocs, os::num_frees);
duke@435:   tty->print_cr("## memory stomp: byte at %p %s object %p", bad, where, memblock);
duke@435:   print_neighbor_blocks(memblock);
duke@435:   fatal("memory stomping error");
duke@435: }
duke@435: 
duke@435: void verify_block(void* memblock) {
duke@435:   size_t size = get_size(memblock);
duke@435:   if (MallocCushion) {
duke@435:     u_char* ptr = (u_char*)memblock - space_before;
duke@435:     for (int i = 0; i < MallocCushion; i++) {
duke@435:       if (ptr[i] != badResourceValue) {
duke@435:         report_heap_error(memblock, ptr+i, "in front of");
duke@435:       }
duke@435:     }
duke@435:     u_char* end = (u_char*)memblock + size + space_after;
duke@435:     for (int j = -MallocCushion; j < 0; j++) {
duke@435:       if (end[j] != badResourceValue) {
duke@435:         report_heap_error(memblock, end+j, "after");
duke@435:       }
duke@435:     }
duke@435:   }
duke@435: }
duke@435: #endif
duke@435: 
duke@435: void* os::malloc(size_t size) {
duke@435:   NOT_PRODUCT(num_mallocs++);
duke@435:   NOT_PRODUCT(alloc_bytes += size);
duke@435: 
duke@435:   if (size == 0) {
duke@435:     // return a valid pointer if size is zero
duke@435:     // if NULL is returned the calling functions assume out of memory.
duke@435:     size = 1;
duke@435:   }
duke@435: 
duke@435:   NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
duke@435:   u_char* ptr = (u_char*)::malloc(size + space_before + space_after);
duke@435: #ifdef ASSERT
duke@435:   if (ptr == NULL) return NULL;
duke@435:   if (MallocCushion) {
duke@435:     for (u_char* p = ptr; p < ptr + MallocCushion; p++) *p = (u_char)badResourceValue;
duke@435:     u_char* end = ptr + space_before + size;
duke@435:     for (u_char* pq = ptr+MallocCushion; pq < end; pq++) *pq = (u_char)uninitBlockPad;
duke@435:     for (u_char* q = end; q < end + MallocCushion; q++) *q = (u_char)badResourceValue;
duke@435:   }
duke@435:   // put size just before data
duke@435:   *size_addr_from_base(ptr) = size;
duke@435: #endif
duke@435:   u_char* memblock = ptr + space_before;
duke@435:   if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
duke@435:     tty->print_cr("os::malloc caught, %lu bytes --> %p", size, memblock);
duke@435:     breakpoint();
duke@435:   }
duke@435:   debug_only(if (paranoid) verify_block(memblock));
duke@435:   if (PrintMalloc && tty != NULL) tty->print_cr("os::malloc %lu bytes --> %p", size, memblock);
duke@435:   return memblock;
duke@435: }
duke@435: 
duke@435: 
duke@435: void* os::realloc(void *memblock, size_t size) {
duke@435:   NOT_PRODUCT(num_mallocs++);
duke@435:   NOT_PRODUCT(alloc_bytes += size);
duke@435: #ifndef ASSERT
duke@435:   return ::realloc(memblock, size);
duke@435: #else
duke@435:   if (memblock == NULL) {
duke@435:     return os::malloc(size);
duke@435:   }
duke@435:   if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
duke@435:     tty->print_cr("os::realloc caught %p", memblock);
duke@435:     breakpoint();
duke@435:   }
duke@435:   verify_block(memblock);
duke@435:   NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
duke@435:   if (size == 0) return NULL;
duke@435:   // always move the block
duke@435:   void* ptr = malloc(size);
duke@435:   if (PrintMalloc) tty->print_cr("os::remalloc %lu bytes, %p --> %p", size, memblock, ptr);
duke@435:   // Copy to new memory if malloc didn't fail
duke@435:   if ( ptr != NULL ) {
duke@435:     memcpy(ptr, memblock, MIN2(size, get_size(memblock)));
duke@435:     if (paranoid) verify_block(ptr);
duke@435:     if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) {
duke@435:       tty->print_cr("os::realloc caught, %lu bytes --> %p", size, ptr);
duke@435:       breakpoint();
duke@435:     }
duke@435:     free(memblock);
duke@435:   }
duke@435:   return ptr;
duke@435: #endif
duke@435: }
duke@435: 
duke@435: 
duke@435: void  os::free(void *memblock) {
duke@435:   NOT_PRODUCT(num_frees++);
duke@435: #ifdef ASSERT
duke@435:   if (memblock == NULL) return;
duke@435:   if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
duke@435:     if (tty != NULL) tty->print_cr("os::free caught %p", memblock);
duke@435:     breakpoint();
duke@435:   }
duke@435:   verify_block(memblock);
duke@435:   if (PrintMalloc && tty != NULL)
duke@435:     // tty->print_cr("os::free %p", memblock);
duke@435:     fprintf(stderr, "os::free %p\n", memblock);
duke@435:   NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
duke@435:   // Added by detlefs.
duke@435:   if (MallocCushion) {
duke@435:     u_char* ptr = (u_char*)memblock - space_before;
duke@435:     for (u_char* p = ptr; p < ptr + MallocCushion; p++) {
duke@435:       guarantee(*p == badResourceValue,
duke@435:                 "Thing freed should be malloc result.");
duke@435:       *p = (u_char)freeBlockPad;
duke@435:     }
duke@435:     size_t size = get_size(memblock);
duke@435:     u_char* end = ptr + space_before + size;
duke@435:     for (u_char* q = end; q < end + MallocCushion; q++) {
duke@435:       guarantee(*q == badResourceValue,
duke@435:                 "Thing freed should be malloc result.");
duke@435:       *q = (u_char)freeBlockPad;
duke@435:     }
duke@435:   }
duke@435: #endif
duke@435:   ::free((char*)memblock - space_before);
duke@435: }
duke@435: 
duke@435: void os::init_random(long initval) {
duke@435:   _rand_seed = initval;
duke@435: }
duke@435: 
duke@435: 
duke@435: long os::random() {
duke@435:   /* standard, well-known linear congruential random generator with
duke@435:    * next_rand = (16807*seed) mod (2**31-1)
duke@435:    * see
duke@435:    * (1) "Random Number Generators: Good Ones Are Hard to Find",
duke@435:    *      S.K. Park and K.W. Miller, Communications of the ACM 31:10 (Oct 1988),
duke@435:    * (2) "Two Fast Implementations of the 'Minimal Standard' Random
duke@435:    *     Number Generator", David G. Carta, Comm. ACM 33, 1 (Jan 1990), pp. 87-88.
duke@435:   */
duke@435:   const long a = 16807;
duke@435:   const unsigned long m = 2147483647;
duke@435:   const long q = m / a;        assert(q == 127773, "weird math");
duke@435:   const long r = m % a;        assert(r == 2836, "weird math");
duke@435: 
duke@435:   // compute az=2^31p+q
duke@435:   unsigned long lo = a * (long)(_rand_seed & 0xFFFF);
duke@435:   unsigned long hi = a * (long)((unsigned long)_rand_seed >> 16);
duke@435:   lo += (hi & 0x7FFF) << 16;
duke@435: 
duke@435:   // if q overflowed, ignore the overflow and increment q
duke@435:   if (lo > m) {
duke@435:     lo &= m;
duke@435:     ++lo;
duke@435:   }
duke@435:   lo += hi >> 15;
duke@435: 
duke@435:   // if (p+q) overflowed, ignore the overflow and increment (p+q)
duke@435:   if (lo > m) {
duke@435:     lo &= m;
duke@435:     ++lo;
duke@435:   }
duke@435:   return (_rand_seed = lo);
duke@435: }
duke@435: 
duke@435: // The INITIALIZED state is distinguished from the SUSPENDED state because the
duke@435: // conditions in which a thread is first started are different from those in which
duke@435: // a suspension is resumed.  These differences make it hard for us to apply the
duke@435: // tougher checks when starting threads that we want to do when resuming them.
duke@435: // However, when start_thread is called as a result of Thread.start, on a Java
duke@435: // thread, the operation is synchronized on the Java Thread object.  So there
duke@435: // cannot be a race to start the thread and hence for the thread to exit while
duke@435: // we are working on it.  Non-Java threads that start Java threads either have
duke@435: // to do so in a context in which races are impossible, or should do appropriate
duke@435: // locking.
duke@435: 
duke@435: void os::start_thread(Thread* thread) {
duke@435:   // guard suspend/resume
duke@435:   MutexLockerEx ml(thread->SR_lock(), Mutex::_no_safepoint_check_flag);
duke@435:   OSThread* osthread = thread->osthread();
duke@435:   osthread->set_state(RUNNABLE);
duke@435:   pd_start_thread(thread);
duke@435: }
duke@435: 
duke@435: //---------------------------------------------------------------------------
duke@435: // Helper functions for fatal error handler
duke@435: 
duke@435: void os::print_hex_dump(outputStream* st, address start, address end, int unitsize) {
duke@435:   assert(unitsize == 1 || unitsize == 2 || unitsize == 4 || unitsize == 8, "just checking");
duke@435: 
duke@435:   int cols = 0;
duke@435:   int cols_per_line = 0;
duke@435:   switch (unitsize) {
duke@435:     case 1: cols_per_line = 16; break;
duke@435:     case 2: cols_per_line = 8;  break;
duke@435:     case 4: cols_per_line = 4;  break;
duke@435:     case 8: cols_per_line = 2;  break;
duke@435:     default: return;
duke@435:   }
duke@435: 
duke@435:   address p = start;
duke@435:   st->print(PTR_FORMAT ":   ", start);
duke@435:   while (p < end) {
duke@435:     switch (unitsize) {
duke@435:       case 1: st->print("%02x", *(u1*)p); break;
duke@435:       case 2: st->print("%04x", *(u2*)p); break;
duke@435:       case 4: st->print("%08x", *(u4*)p); break;
duke@435:       case 8: st->print("%016" FORMAT64_MODIFIER "x", *(u8*)p); break;
duke@435:     }
duke@435:     p += unitsize;
duke@435:     cols++;
duke@435:     if (cols >= cols_per_line && p < end) {
duke@435:        cols = 0;
duke@435:        st->cr();
duke@435:        st->print(PTR_FORMAT ":   ", p);
duke@435:     } else {
duke@435:        st->print(" ");
duke@435:     }
duke@435:   }
duke@435:   st->cr();
duke@435: }
duke@435: 
duke@435: void os::print_environment_variables(outputStream* st, const char** env_list,
duke@435:                                      char* buffer, int len) {
duke@435:   if (env_list) {
duke@435:     st->print_cr("Environment Variables:");
duke@435: 
duke@435:     for (int i = 0; env_list[i] != NULL; i++) {
duke@435:       if (getenv(env_list[i], buffer, len)) {
duke@435:         st->print(env_list[i]);
duke@435:         st->print("=");
duke@435:         st->print_cr(buffer);
duke@435:       }
duke@435:     }
duke@435:   }
duke@435: }
duke@435: 
duke@435: void os::print_cpu_info(outputStream* st) {
duke@435:   // cpu
duke@435:   st->print("CPU:");
duke@435:   st->print("total %d", os::processor_count());
duke@435:   // It's not safe to query number of active processors after crash
duke@435:   // st->print("(active %d)", os::active_processor_count());
duke@435:   st->print(" %s", VM_Version::cpu_features());
duke@435:   st->cr();
duke@435: }
duke@435: 
duke@435: void os::print_date_and_time(outputStream *st) {
duke@435:   time_t tloc;
duke@435:   (void)time(&tloc);
duke@435:   st->print("time: %s", ctime(&tloc));  // ctime adds newline.
duke@435: 
duke@435:   double t = os::elapsedTime();
duke@435:   // NOTE: It tends to crash after a SEGV if we want to printf("%f",...) in
duke@435:   //       Linux. Must be a bug in glibc ? Workaround is to round "t" to int
duke@435:   //       before printf. We lost some precision, but who cares?
duke@435:   st->print_cr("elapsed time: %d seconds", (int)t);
duke@435: }
duke@435: 
duke@435: 
duke@435: // Looks like all platforms except IA64 can use the same function to check
duke@435: // if C stack is walkable beyond current frame. The check for fp() is not
duke@435: // necessary on Sparc, but it's harmless.
duke@435: bool os::is_first_C_frame(frame* fr) {
duke@435: #ifdef IA64
duke@435:   // In order to walk native frames on Itanium, we need to access the unwind
duke@435:   // table, which is inside ELF. We don't want to parse ELF after fatal error,
duke@435:   // so return true for IA64. If we need to support C stack walking on IA64,
duke@435:   // this function needs to be moved to CPU specific files, as fp() on IA64
duke@435:   // is register stack, which grows towards higher memory address.
duke@435:   return true;
duke@435: #endif
duke@435: 
duke@435:   // Load up sp, fp, sender sp and sender fp, check for reasonable values.
duke@435:   // Check usp first, because if that's bad the other accessors may fault
duke@435:   // on some architectures.  Ditto ufp second, etc.
duke@435:   uintptr_t fp_align_mask = (uintptr_t)(sizeof(address)-1);
duke@435:   // sp on amd can be 32 bit aligned.
duke@435:   uintptr_t sp_align_mask = (uintptr_t)(sizeof(int)-1);
duke@435: 
duke@435:   uintptr_t usp    = (uintptr_t)fr->sp();
duke@435:   if ((usp & sp_align_mask) != 0) return true;
duke@435: 
duke@435:   uintptr_t ufp    = (uintptr_t)fr->fp();
duke@435:   if ((ufp & fp_align_mask) != 0) return true;
duke@435: 
duke@435:   uintptr_t old_sp = (uintptr_t)fr->sender_sp();
duke@435:   if ((old_sp & sp_align_mask) != 0) return true;
duke@435:   if (old_sp == 0 || old_sp == (uintptr_t)-1) return true;
duke@435: 
duke@435:   uintptr_t old_fp = (uintptr_t)fr->link();
duke@435:   if ((old_fp & fp_align_mask) != 0) return true;
duke@435:   if (old_fp == 0 || old_fp == (uintptr_t)-1 || old_fp == ufp) return true;
duke@435: 
duke@435:   // stack grows downwards; if old_fp is below current fp or if the stack
duke@435:   // frame is too large, either the stack is corrupted or fp is not saved
duke@435:   // on stack (i.e. on x86, ebp may be used as general register). The stack
duke@435:   // is not walkable beyond current frame.
duke@435:   if (old_fp < ufp) return true;
duke@435:   if (old_fp - ufp > 64 * K) return true;
duke@435: 
duke@435:   return false;
duke@435: }
duke@435: 
duke@435: #ifdef ASSERT
duke@435: extern "C" void test_random() {
duke@435:   const double m = 2147483647;
duke@435:   double mean = 0.0, variance = 0.0, t;
duke@435:   long reps = 10000;
duke@435:   unsigned long seed = 1;
duke@435: 
duke@435:   tty->print_cr("seed %ld for %ld repeats...", seed, reps);
duke@435:   os::init_random(seed);
duke@435:   long num;
duke@435:   for (int k = 0; k < reps; k++) {
duke@435:     num = os::random();
duke@435:     double u = (double)num / m;
duke@435:     assert(u >= 0.0 && u <= 1.0, "bad random number!");
duke@435: 
duke@435:     // calculate mean and variance of the random sequence
duke@435:     mean += u;
duke@435:     variance += (u*u);
duke@435:   }
duke@435:   mean /= reps;
duke@435:   variance /= (reps - 1);
duke@435: 
duke@435:   assert(num == 1043618065, "bad seed");
duke@435:   tty->print_cr("mean of the 1st 10000 numbers: %f", mean);
duke@435:   tty->print_cr("variance of the 1st 10000 numbers: %f", variance);
duke@435:   const double eps = 0.0001;
duke@435:   t = fabsd(mean - 0.5018);
duke@435:   assert(t < eps, "bad mean");
duke@435:   t = (variance - 0.3355) < 0.0 ? -(variance - 0.3355) : variance - 0.3355;
duke@435:   assert(t < eps, "bad variance");
duke@435: }
duke@435: #endif
duke@435: 
duke@435: 
duke@435: // Set up the boot classpath.
duke@435: 
duke@435: char* os::format_boot_path(const char* format_string,
duke@435:                            const char* home,
duke@435:                            int home_len,
duke@435:                            char fileSep,
duke@435:                            char pathSep) {
duke@435:     assert((fileSep == '/' && pathSep == ':') ||
duke@435:            (fileSep == '\\' && pathSep == ';'), "unexpected seperator chars");
duke@435: 
duke@435:     // Scan the format string to determine the length of the actual
duke@435:     // boot classpath, and handle platform dependencies as well.
duke@435:     int formatted_path_len = 0;
duke@435:     const char* p;
duke@435:     for (p = format_string; *p != 0; ++p) {
duke@435:         if (*p == '%') formatted_path_len += home_len - 1;
duke@435:         ++formatted_path_len;
duke@435:     }
duke@435: 
duke@435:     char* formatted_path = NEW_C_HEAP_ARRAY(char, formatted_path_len + 1);
duke@435:     if (formatted_path == NULL) {
duke@435:         return NULL;
duke@435:     }
duke@435: 
duke@435:     // Create boot classpath from format, substituting separator chars and
duke@435:     // java home directory.
duke@435:     char* q = formatted_path;
duke@435:     for (p = format_string; *p != 0; ++p) {
duke@435:         switch (*p) {
duke@435:         case '%':
duke@435:             strcpy(q, home);
duke@435:             q += home_len;
duke@435:             break;
duke@435:         case '/':
duke@435:             *q++ = fileSep;
duke@435:             break;
duke@435:         case ':':
duke@435:             *q++ = pathSep;
duke@435:             break;
duke@435:         default:
duke@435:             *q++ = *p;
duke@435:         }
duke@435:     }
duke@435:     *q = '\0';
duke@435: 
duke@435:     assert((q - formatted_path) == formatted_path_len, "formatted_path size botched");
duke@435:     return formatted_path;
duke@435: }
duke@435: 
duke@435: 
duke@435: bool os::set_boot_path(char fileSep, char pathSep) {
duke@435: 
duke@435:     const char* home = Arguments::get_java_home();
duke@435:     int home_len = (int)strlen(home);
duke@435: 
duke@435:     static const char* meta_index_dir_format = "%/lib/";
duke@435:     static const char* meta_index_format = "%/lib/meta-index";
duke@435:     char* meta_index = format_boot_path(meta_index_format, home, home_len, fileSep, pathSep);
duke@435:     if (meta_index == NULL) return false;
duke@435:     char* meta_index_dir = format_boot_path(meta_index_dir_format, home, home_len, fileSep, pathSep);
duke@435:     if (meta_index_dir == NULL) return false;
duke@435:     Arguments::set_meta_index_path(meta_index, meta_index_dir);
duke@435: 
duke@435:     // Any modification to the JAR-file list, for the boot classpath must be
duke@435:     // aligned with install/install/make/common/Pack.gmk. Note: boot class
duke@435:     // path class JARs, are stripped for StackMapTable to reduce download size.
duke@435:     static const char classpath_format[] =
duke@435:         "%/lib/resources.jar:"
duke@435:         "%/lib/rt.jar:"
duke@435:         "%/lib/sunrsasign.jar:"
duke@435:         "%/lib/jsse.jar:"
duke@435:         "%/lib/jce.jar:"
duke@435:         "%/lib/charsets.jar:"
duke@435:         "%/classes";
duke@435:     char* sysclasspath = format_boot_path(classpath_format, home, home_len, fileSep, pathSep);
duke@435:     if (sysclasspath == NULL) return false;
duke@435:     Arguments::set_sysclasspath(sysclasspath);
duke@435: 
duke@435:     return true;
duke@435: }
duke@435: 
duke@435: void os::set_memory_serialize_page(address page) {
duke@435:   int count = log2_intptr(sizeof(class JavaThread)) - log2_intptr(64);
duke@435:   _mem_serialize_page = (volatile int32_t *)page;
duke@435:   // We initialize the serialization page shift count here
duke@435:   // We assume a cache line size of 64 bytes
duke@435:   assert(SerializePageShiftCount == count,
duke@435:          "thread size changed, fix SerializePageShiftCount constant");
duke@435:   set_serialize_page_mask((uintptr_t)(vm_page_size() - sizeof(int32_t)));
duke@435: }
duke@435: 
xlu@490: static volatile intptr_t SerializePageLock = 0;
xlu@490: 
duke@435: // This method is called from signal handler when SIGSEGV occurs while the current
duke@435: // thread tries to store to the "read-only" memory serialize page during state
duke@435: // transition.
duke@435: void os::block_on_serialize_page_trap() {
duke@435:   if (TraceSafepoint) {
duke@435:     tty->print_cr("Block until the serialize page permission restored");
duke@435:   }
xlu@490:   // When VMThread is holding the SerializePageLock during modifying the
duke@435:   // access permission of the memory serialize page, the following call
duke@435:   // will block until the permission of that page is restored to rw.
duke@435:   // Generally, it is unsafe to manipulate locks in signal handlers, but in
duke@435:   // this case, it's OK as the signal is synchronous and we know precisely when
xlu@490:   // it can occur.
xlu@490:   Thread::muxAcquire(&SerializePageLock, "set_memory_serialize_page");
xlu@490:   Thread::muxRelease(&SerializePageLock);
duke@435: }
duke@435: 
duke@435: // Serialize all thread state variables
duke@435: void os::serialize_thread_states() {
duke@435:   // On some platforms such as Solaris & Linux, the time duration of the page
duke@435:   // permission restoration is observed to be much longer than expected  due to
duke@435:   // scheduler starvation problem etc. To avoid the long synchronization
xlu@490:   // time and expensive page trap spinning, 'SerializePageLock' is used to block
xlu@490:   // the mutator thread if such case is encountered. See bug 6546278 for details.
xlu@490:   Thread::muxAcquire(&SerializePageLock, "serialize_thread_states");
coleenp@672:   os::protect_memory((char *)os::get_memory_serialize_page(),
coleenp@672:                      os::vm_page_size(), MEM_PROT_READ, /*is_committed*/true );
coleenp@672:   os::unguard_memory((char *)os::get_memory_serialize_page(), os::vm_page_size());
xlu@490:   Thread::muxRelease(&SerializePageLock);
duke@435: }
duke@435: 
duke@435: // Returns true if the current stack pointer is above the stack shadow
duke@435: // pages, false otherwise.
duke@435: 
duke@435: bool os::stack_shadow_pages_available(Thread *thread, methodHandle method) {
duke@435:   assert(StackRedPages > 0 && StackYellowPages > 0,"Sanity check");
duke@435:   address sp = current_stack_pointer();
duke@435:   // Check if we have StackShadowPages above the yellow zone.  This parameter
duke@435:   // is dependant on the depth of the maximum VM call stack possible from
duke@435:   // the handler for stack overflow.  'instanceof' in the stack overflow
duke@435:   // handler or a println uses at least 8k stack of VM and native code
duke@435:   // respectively.
duke@435:   const int framesize_in_bytes =
duke@435:     Interpreter::size_top_interpreter_activation(method()) * wordSize;
duke@435:   int reserved_area = ((StackShadowPages + StackRedPages + StackYellowPages)
duke@435:                       * vm_page_size()) + framesize_in_bytes;
duke@435:   // The very lower end of the stack
duke@435:   address stack_limit = thread->stack_base() - thread->stack_size();
duke@435:   return (sp > (stack_limit + reserved_area));
duke@435: }
duke@435: 
duke@435: size_t os::page_size_for_region(size_t region_min_size, size_t region_max_size,
duke@435:                                 uint min_pages)
duke@435: {
duke@435:   assert(min_pages > 0, "sanity");
duke@435:   if (UseLargePages) {
duke@435:     const size_t max_page_size = region_max_size / min_pages;
duke@435: 
duke@435:     for (unsigned int i = 0; _page_sizes[i] != 0; ++i) {
duke@435:       const size_t sz = _page_sizes[i];
duke@435:       const size_t mask = sz - 1;
duke@435:       if ((region_min_size & mask) == 0 && (region_max_size & mask) == 0) {
duke@435:         // The largest page size with no fragmentation.
duke@435:         return sz;
duke@435:       }
duke@435: 
duke@435:       if (sz <= max_page_size) {
duke@435:         // The largest page size that satisfies the min_pages requirement.
duke@435:         return sz;
duke@435:       }
duke@435:     }
duke@435:   }
duke@435: 
duke@435:   return vm_page_size();
duke@435: }
duke@435: 
duke@435: #ifndef PRODUCT
duke@435: void os::trace_page_sizes(const char* str, const size_t region_min_size,
duke@435:                           const size_t region_max_size, const size_t page_size,
duke@435:                           const char* base, const size_t size)
duke@435: {
duke@435:   if (TracePageSizes) {
duke@435:     tty->print_cr("%s:  min=" SIZE_FORMAT " max=" SIZE_FORMAT
duke@435:                   " pg_sz=" SIZE_FORMAT " base=" PTR_FORMAT
duke@435:                   " size=" SIZE_FORMAT,
duke@435:                   str, region_min_size, region_max_size,
duke@435:                   page_size, base, size);
duke@435:   }
duke@435: }
duke@435: #endif  // #ifndef PRODUCT
duke@435: 
duke@435: // This is the working definition of a server class machine:
duke@435: // >= 2 physical CPU's and >=2GB of memory, with some fuzz
duke@435: // because the graphics memory (?) sometimes masks physical memory.
duke@435: // If you want to change the definition of a server class machine
duke@435: // on some OS or platform, e.g., >=4GB on Windohs platforms,
duke@435: // then you'll have to parameterize this method based on that state,
duke@435: // as was done for logical processors here, or replicate and
duke@435: // specialize this method for each platform.  (Or fix os to have
duke@435: // some inheritance structure and use subclassing.  Sigh.)
duke@435: // If you want some platform to always or never behave as a server
duke@435: // class machine, change the setting of AlwaysActAsServerClassMachine
duke@435: // and NeverActAsServerClassMachine in globals*.hpp.
duke@435: bool os::is_server_class_machine() {
duke@435:   // First check for the early returns
duke@435:   if (NeverActAsServerClassMachine) {
duke@435:     return false;
duke@435:   }
duke@435:   if (AlwaysActAsServerClassMachine) {
duke@435:     return true;
duke@435:   }
duke@435:   // Then actually look at the machine
duke@435:   bool         result            = false;
duke@435:   const unsigned int    server_processors = 2;
duke@435:   const julong server_memory     = 2UL * G;
duke@435:   // We seem not to get our full complement of memory.
duke@435:   //     We allow some part (1/8?) of the memory to be "missing",
duke@435:   //     based on the sizes of DIMMs, and maybe graphics cards.
duke@435:   const julong missing_memory   = 256UL * M;
duke@435: 
duke@435:   /* Is this a server class machine? */
duke@435:   if ((os::active_processor_count() >= (int)server_processors) &&
duke@435:       (os::physical_memory() >= (server_memory - missing_memory))) {
duke@435:     const unsigned int logical_processors =
duke@435:       VM_Version::logical_processors_per_package();
duke@435:     if (logical_processors > 1) {
duke@435:       const unsigned int physical_packages =
duke@435:         os::active_processor_count() / logical_processors;
duke@435:       if (physical_packages > server_processors) {
duke@435:         result = true;
duke@435:       }
duke@435:     } else {
duke@435:       result = true;
duke@435:     }
duke@435:   }
duke@435:   return result;
duke@435: }