jdk8-mips64-public/hotspot: src/share/vm/runtime/os.cpp@72053ed6f8d4 (annotated)

src/share/vm/runtime/os.cpp@72053ed6f8d4 (annotated)

src/share/vm/runtime/os.cpp

Thu, 24 Nov 2016 11:27:57 +0100

author: tschatzl
date: Thu, 24 Nov 2016 11:27:57 +0100
changeset 9982: 72053ed6f8d4
parent 9955: 02b4fd2f9041
child 10015: eb7ce841ccec
permissions: -rw-r--r--

8057003: Large reference arrays cause extremely long synchronization times
Summary: Slice large object arrays into parts so that the synchronization of marking threads with an STW pause request does not take long.
Reviewed-by: ehelin, pliden
Contributed-by: maoliang.ml@alibaba-inc.com

 /*
  * Copyright (c) 1997, 2018, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */
 #include "precompiled.hpp"
 #include "classfile/classLoader.hpp"
 #include "classfile/javaClasses.hpp"
 #include "classfile/systemDictionary.hpp"
 #include "classfile/vmSymbols.hpp"
 #include "code/icBuffer.hpp"
 #include "code/vtableStubs.hpp"
 #include "gc_implementation/shared/vmGCOperations.hpp"
 #include "interpreter/interpreter.hpp"
 #include "memory/allocation.inline.hpp"
 #ifdef ASSERT
 #include "memory/guardedMemory.hpp"
 #endif
 #include "oops/oop.inline.hpp"
 #include "prims/jvm.h"
 #include "prims/jvm_misc.hpp"
 #include "prims/privilegedStack.hpp"
 #include "runtime/arguments.hpp"
 #include "runtime/frame.inline.hpp"
 #include "runtime/interfaceSupport.hpp"
 #include "runtime/java.hpp"
 #include "runtime/javaCalls.hpp"
 #include "runtime/mutexLocker.hpp"
 #include "runtime/os.hpp"
 #include "runtime/stubRoutines.hpp"
 #include "runtime/thread.inline.hpp"
 #include "services/attachListener.hpp"
 #include "services/nmtCommon.hpp"
 #include "services/mallocTracker.hpp"
 #include "services/memTracker.hpp"
 #include "services/threadService.hpp"
 #include "utilities/defaultStream.hpp"
 #include "utilities/events.hpp"
 #ifdef TARGET_OS_FAMILY_linux
 # include "os_linux.inline.hpp"
 #endif
 #ifdef TARGET_OS_FAMILY_solaris
 # include "os_solaris.inline.hpp"
 #endif
 #ifdef TARGET_OS_FAMILY_windows
 # include "os_windows.inline.hpp"
 #endif
 #ifdef TARGET_OS_FAMILY_bsd
 # include "os_bsd.inline.hpp"
 #endif
 # include <signal.h>
 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
 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;
 int               os::_initial_active_processor_count = 0;
 size_t            os::_page_sizes[os::page_sizes_max];
 #ifndef PRODUCT
 julong os::num_mallocs = 0;         // # of calls to malloc/realloc
 julong os::alloc_bytes = 0;         // # of bytes allocated
 julong os::num_frees = 0;           // # of calls to free
 julong os::free_bytes = 0;          // # of bytes freed
 #endif
 static juint cur_malloc_words = 0;  // current size for MallocMaxTestWords
 void os_init_globals() {
   // Called from init_globals().
   // See Threads::create_vm() in thread.cpp, and init.cpp.
   os::init_globals();
 }
 static time_t get_timezone(const struct tm* time_struct) {
 #if defined(_ALLBSD_SOURCE)
   return time_struct->tm_gmtoff;
 #elif defined(_WINDOWS)
   long zone;
   _get_timezone(&zone);
   return static_cast<time_t>(zone);
 #else
   return timezone;
 #endif
 }
 int os::snprintf(char* buf, size_t len, const char* fmt, ...) {
   va_list args;
   va_start(args, fmt);
   int result = os::vsnprintf(buf, len, fmt, args);
   va_end(args);
   return result;
 }
 // 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 = javaTimeMillis();
   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
   struct tm time_struct;
   if (localtime_pd(&seconds_since_19700101, &time_struct) == NULL) {
     assert(false, "Failed localtime_pd");
     return NULL;
   }
   const time_t zone = get_timezone(&time_struct);
   // 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_pd() 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_pd() 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;
   }
 }
 // The mapping from OS priority back to Java priority may be inexact because
 // Java priorities can map M:1 with native priorities. If you want the definite
 // Java priority then use JavaThread::java_priority()
 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;
   if (java_to_os_priority[MaxPriority] > java_to_os_priority[MinPriority]) {
     for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] > os_prio; p--) ;
   } else {
     // niceness values are in reverse order
     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);
         Klass* k = SystemDictionary::resolve_or_null(vmSymbols::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,
             vmSymbols::dispatch_name(),
             vmSymbols::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::init_before_ergo() {
   initialize_initial_active_processor_count();
   // We need to initialize large page support here because ergonomics takes some
   // decisions depending on large page support and the calculated large page size.
   large_page_init();
   // VM version initialization identifies some characteristics of the
   // the platform that are used during ergonomic decisions.
   VM_Version::init_before_ergo();
 }
 void os::signal_init() {
   if (!ReduceSignalUsage) {
     // Setup JavaThread for processing signals
     EXCEPTION_MARK;
     Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::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,
                            vmSymbols::object_initializer_name(),
                            vmSymbols::threadgroup_string_void_signature(),
                            thread_group,
                            string,
                            CHECK);
     KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
     JavaCalls::call_special(&result,
                             thread_group,
                             group,
                             vmSymbols::add_method_name(),
                             vmSymbols::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.
     if (dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
                        "verify")) {
       dll_load(buffer, ebuf, sizeof(ebuf));
     }
     // Load java dll
     if (dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
                        "java")) {
       _native_java_library = dll_load(buffer, ebuf, sizeof(ebuf));
     }
     if (_native_java_library == NULL) {
       vm_exit_during_initialization("Unable to load native library", ebuf);
     }
 #if defined(__OpenBSD__)
     // Work-around OpenBSD's lack of $ORIGIN support by pre-loading libnet.so
     // ignore errors
     if (dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
                        "net")) {
       dll_load(buffer, ebuf, sizeof(ebuf));
     }
 #endif
   }
   static jboolean onLoaded = JNI_FALSE;
   if (onLoaded) {
     // We may have to wait to fire OnLoad until TLS is initialized.
     if (ThreadLocalStorage::is_initialized()) {
       // The JNI_OnLoad handling is normally done by method load in
       // java.lang.ClassLoader$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, 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);
         onLoaded = JNI_TRUE;
         if (!Threads::is_supported_jni_version_including_1_1(ver)) {
           vm_exit_during_initialization("Unsupported JNI version");
         }
       }
     }
   }
   return _native_java_library;
 }
 /*
  * Support for finding Agent_On(Un)Load/Attach<_lib_name> if it exists.
  * If check_lib == true then we are looking for an
  * Agent_OnLoad_lib_name or Agent_OnAttach_lib_name function to determine if
  * this library is statically linked into the image.
  * If check_lib == false then we will look for the appropriate symbol in the
  * executable if agent_lib->is_static_lib() == true or in the shared library
  * referenced by 'handle'.
  */
 void* os::find_agent_function(AgentLibrary *agent_lib, bool check_lib,
                               const char *syms[], size_t syms_len) {
   assert(agent_lib != NULL, "sanity check");
   const char *lib_name;
   void *handle = agent_lib->os_lib();
   void *entryName = NULL;
   char *agent_function_name;
   size_t i;
   // If checking then use the agent name otherwise test is_static_lib() to
   // see how to process this lookup
   lib_name = ((check_lib || agent_lib->is_static_lib()) ? agent_lib->name() : NULL);
   for (i = 0; i < syms_len; i++) {
     agent_function_name = build_agent_function_name(syms[i], lib_name, agent_lib->is_absolute_path());
     if (agent_function_name == NULL) {
       break;
     }
     entryName = dll_lookup(handle, agent_function_name);
     FREE_C_HEAP_ARRAY(char, agent_function_name, mtThread);
     if (entryName != NULL) {
       break;
     }
   }
   return entryName;
 }
 // See if the passed in agent is statically linked into the VM image.
 bool os::find_builtin_agent(AgentLibrary *agent_lib, const char *syms[],
                             size_t syms_len) {
   void *ret;
   void *proc_handle;
   void *save_handle;
   assert(agent_lib != NULL, "sanity check");
   if (agent_lib->name() == NULL) {
     return false;
   }
   proc_handle = get_default_process_handle();
   // Check for Agent_OnLoad/Attach_lib_name function
   save_handle = agent_lib->os_lib();
   // We want to look in this process' symbol table.
   agent_lib->set_os_lib(proc_handle);
   ret = find_agent_function(agent_lib, true, syms, syms_len);
   if (ret != NULL) {
     // Found an entry point like Agent_OnLoad_lib_name so we have a static agent
     agent_lib->set_valid();
     agent_lib->set_static_lib(true);
     return true;
   }
   agent_lib->set_os_lib(save_handle);
   return false;
 }
 // --------------------- heap allocation utilities ---------------------
 char *os::strdup(const char *str, MEMFLAGS flags) {
   size_t size = strlen(str);
   char *dup_str = (char *)malloc(size + 1, flags);
   if (dup_str == NULL) return NULL;
   strcpy(dup_str, str);
   return dup_str;
 }
 #define paranoid                 0  /* only set to 1 if you suspect checking code has bug */
 #ifdef ASSERT
 static void verify_memory(void* ptr) {
   GuardedMemory guarded(ptr);
   if (!guarded.verify_guards()) {
     tty->print_cr("## nof_mallocs = " UINT64_FORMAT ", nof_frees = " UINT64_FORMAT, os::num_mallocs, os::num_frees);
     tty->print_cr("## memory stomp:");
     guarded.print_on(tty);
     fatal("memory stomping error");
   }
 }
 #endif
 //
 // This function supports testing of the malloc out of memory
 // condition without really running the system out of memory.
 //
 static u_char* testMalloc(size_t alloc_size) {
   assert(MallocMaxTestWords > 0, "sanity check");
   if ((cur_malloc_words + (alloc_size / BytesPerWord)) > MallocMaxTestWords) {
     return NULL;
   }
   u_char* ptr = (u_char*)::malloc(alloc_size);
   if (ptr != NULL) {
     Atomic::add(((jint) (alloc_size / BytesPerWord)),
                 (volatile jint *) &cur_malloc_words);
   }
   return ptr;
 }
 void* os::malloc(size_t size, MEMFLAGS flags) {
   return os::malloc(size, flags, CALLER_PC);
 }
 void* os::malloc(size_t size, MEMFLAGS memflags, const NativeCallStack& stack) {
   NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1));
   NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size));
   // Since os::malloc can be called when the libjvm.{dll,so} is
   // first loaded and we don't have a thread yet we must accept NULL also here.
   assert(!os::ThreadCrashProtection::is_crash_protected(ThreadLocalStorage::thread()),
          "malloc() not allowed when crash protection is set");
   if (size == 0) {
     // return a valid pointer if size is zero
     // if NULL is returned the calling functions assume out of memory.
     size = 1;
   }
   // NMT support
   NMT_TrackingLevel level = MemTracker::tracking_level();
   size_t            nmt_header_size = MemTracker::malloc_header_size(level);
 #ifndef ASSERT
   const size_t alloc_size = size + nmt_header_size;
 #else
   const size_t alloc_size = GuardedMemory::get_total_size(size + nmt_header_size);
   if (size + nmt_header_size > alloc_size) { // Check for rollover.
     return NULL;
   }
 #endif
   NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
   u_char* ptr;
   if (MallocMaxTestWords > 0) {
     ptr = testMalloc(alloc_size);
   } else {
     ptr = (u_char*)::malloc(alloc_size);
   }
 #ifdef ASSERT
   if (ptr == NULL) {
     return NULL;
   }
   // Wrap memory with guard
   GuardedMemory guarded(ptr, size + nmt_header_size);
   ptr = guarded.get_user_ptr();
 #endif
   if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) {
     tty->print_cr("os::malloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, ptr);
     breakpoint();
   }
   debug_only(if (paranoid) verify_memory(ptr));
   if (PrintMalloc && tty != NULL) {
     tty->print_cr("os::malloc " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, ptr);
   }
   // we do not track guard memory
   return MemTracker::record_malloc((address)ptr, size, memflags, stack, level);
 }
 void* os::realloc(void *memblock, size_t size, MEMFLAGS flags) {
   return os::realloc(memblock, size, flags, CALLER_PC);
 }
 void* os::realloc(void *memblock, size_t size, MEMFLAGS memflags, const NativeCallStack& stack) {
 #ifndef ASSERT
   NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1));
   NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size));
    // NMT support
   void* membase = MemTracker::record_free(memblock);
   NMT_TrackingLevel level = MemTracker::tracking_level();
   size_t  nmt_header_size = MemTracker::malloc_header_size(level);
   void* ptr = ::realloc(membase, size + nmt_header_size);
   return MemTracker::record_malloc(ptr, size, memflags, stack, level);
 #else
   if (memblock == NULL) {
     return os::malloc(size, memflags, stack);
   }
   if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
     tty->print_cr("os::realloc caught " PTR_FORMAT, memblock);
     breakpoint();
   }
   // NMT support
   void* membase = MemTracker::malloc_base(memblock);
   verify_memory(membase);
   NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
   if (size == 0) {
     return NULL;
   }
   // always move the block
   void* ptr = os::malloc(size, memflags, stack);
   if (PrintMalloc) {
     tty->print_cr("os::remalloc " SIZE_FORMAT " bytes, " PTR_FORMAT " --> " PTR_FORMAT, size, memblock, ptr);
   }
   // Copy to new memory if malloc didn't fail
   if ( ptr != NULL ) {
     GuardedMemory guarded(MemTracker::malloc_base(memblock));
     // Guard's user data contains NMT header
     size_t memblock_size = guarded.get_user_size() - MemTracker::malloc_header_size(memblock);
     memcpy(ptr, memblock, MIN2(size, memblock_size));
     if (paranoid) verify_memory(MemTracker::malloc_base(ptr));
     if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) {
       tty->print_cr("os::realloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, ptr);
       breakpoint();
     }
     os::free(memblock);
   }
   return ptr;
 #endif
 }
 void  os::free(void *memblock, MEMFLAGS memflags) {
   NOT_PRODUCT(inc_stat_counter(&num_frees, 1));
 #ifdef ASSERT
   if (memblock == NULL) return;
   if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
     if (tty != NULL) tty->print_cr("os::free caught " PTR_FORMAT, memblock);
     breakpoint();
   }
   void* membase = MemTracker::record_free(memblock);
   verify_memory(membase);
   NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
   GuardedMemory guarded(membase);
   size_t size = guarded.get_user_size();
   inc_stat_counter(&free_bytes, size);
   membase = guarded.release_for_freeing();
   if (PrintMalloc && tty != NULL) {
       fprintf(stderr, "os::free " SIZE_FORMAT " bytes --> " PTR_FORMAT "\n", size, (uintptr_t)membase);
   }
   ::free(membase);
 #else
   void* membase = MemTracker::record_free(memblock);
   ::free(membase);
 #endif
 }
 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("%s", env_list[i]);
         st->print("=");
         st->print_cr("%s", 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()); but we can
   // print the initial number of active processors.
   // We access the raw value here because the assert in the accessor will
   // fail if the crash occurs before initialization of this value.
   st->print(" (initial active %d)", _initial_active_processor_count);
   st->print(" %s", VM_Version::cpu_features());
   st->cr();
   pd_print_cpu_info(st);
 }
 void os::print_date_and_time(outputStream *st, char* buf, size_t buflen) {
   const int secs_per_day  = 86400;
   const int secs_per_hour = 3600;
   const int secs_per_min  = 60;
   time_t tloc;
   (void)time(&tloc);
   st->print("time: %s", ctime(&tloc));  // ctime adds newline.
   struct tm tz;
   if (localtime_pd(&tloc, &tz) != NULL) {
     ::strftime(buf, buflen, "%Z", &tz);
     st->print_cr("timezone: %s", buf);
   }
   double t = os::elapsedTime();
   // NOTE: a crash using printf("%f",...) on Linux was historically noted here.
   int eltime = (int)t;  // elapsed time in seconds
   int eltimeFraction = (int) ((t - eltime) * 1000000);
   // print elapsed time in a human-readable format:
   int eldays = eltime / secs_per_day;
   int day_secs = eldays * secs_per_day;
   int elhours = (eltime - day_secs) / secs_per_hour;
   int hour_secs = elhours * secs_per_hour;
   int elmins = (eltime - day_secs - hour_secs) / secs_per_min;
   int minute_secs = elmins * secs_per_min;
   int elsecs = (eltime - day_secs - hour_secs - minute_secs);
   st->print_cr("elapsed time: %d.%06d seconds (%dd %dh %dm %ds)", eltime, eltimeFraction, eldays, elhours, elmins, elsecs);
 }
 // moved from debug.cpp (used to be find()) but still called from there
 // The verbose parameter is only set by the debug code in one case
 void os::print_location(outputStream* st, intptr_t x, bool verbose) {
   address addr = (address)x;
   CodeBlob* b = CodeCache::find_blob_unsafe(addr);
   if (b != NULL) {
     if (b->is_buffer_blob()) {
       // the interpreter is generated into a buffer blob
       InterpreterCodelet* i = Interpreter::codelet_containing(addr);
       if (i != NULL) {
         st->print_cr(INTPTR_FORMAT " is at code_begin+%d in an Interpreter codelet", addr, (int)(addr - i->code_begin()));
         i->print_on(st);
         return;
       }
       if (Interpreter::contains(addr)) {
         st->print_cr(INTPTR_FORMAT " is pointing into interpreter code"
                      " (not bytecode specific)", addr);
         return;
       }
       //
       if (AdapterHandlerLibrary::contains(b)) {
         st->print_cr(INTPTR_FORMAT " is at code_begin+%d in an AdapterHandler", addr, (int)(addr - b->code_begin()));
         AdapterHandlerLibrary::print_handler_on(st, b);
       }
       // the stubroutines are generated into a buffer blob
       StubCodeDesc* d = StubCodeDesc::desc_for(addr);
       if (d != NULL) {
         st->print_cr(INTPTR_FORMAT " is at begin+%d in a stub", addr, (int)(addr - d->begin()));
         d->print_on(st);
         st->cr();
         return;
       }
       if (StubRoutines::contains(addr)) {
         st->print_cr(INTPTR_FORMAT " is pointing to an (unnamed) "
                      "stub routine", addr);
         return;
       }
       // the InlineCacheBuffer is using stubs generated into a buffer blob
       if (InlineCacheBuffer::contains(addr)) {
         st->print_cr(INTPTR_FORMAT " is pointing into InlineCacheBuffer", addr);
         return;
       }
       VtableStub* v = VtableStubs::stub_containing(addr);
       if (v != NULL) {
         st->print_cr(INTPTR_FORMAT " is at entry_point+%d in a vtable stub", addr, (int)(addr - v->entry_point()));
         v->print_on(st);
         st->cr();
         return;
       }
     }
     nmethod* nm = b->as_nmethod_or_null();
     if (nm != NULL) {
       ResourceMark rm;
       st->print(INTPTR_FORMAT " is at entry_point+%d in (nmethod*)" INTPTR_FORMAT,
                 addr, (int)(addr - nm->entry_point()), nm);
       if (verbose) {
         st->print(" for ");
         nm->method()->print_value_on(st);
       }
       st->cr();
       nm->print_nmethod(verbose);
       return;
     }
     st->print_cr(INTPTR_FORMAT " is at code_begin+%d in ", addr, (int)(addr - b->code_begin()));
     b->print_on(st);
     return;
   }
   if (Universe::heap()->is_in(addr)) {
     HeapWord* p = Universe::heap()->block_start(addr);
     bool print = false;
     // If we couldn't find it it just may mean that heap wasn't parseable
     // See if we were just given an oop directly
     if (p != NULL && Universe::heap()->block_is_obj(p)) {
       print = true;
     } else if (p == NULL && ((oopDesc*)addr)->is_oop()) {
       p = (HeapWord*) addr;
       print = true;
     }
     if (print) {
       if (p == (HeapWord*) addr) {
         st->print_cr(INTPTR_FORMAT " is an oop", addr);
       } else {
         st->print_cr(INTPTR_FORMAT " is pointing into object: " INTPTR_FORMAT, addr, p);
       }
       oop(p)->print_on(st);
       return;
     }
   } else {
     if (Universe::heap()->is_in_reserved(addr)) {
       st->print_cr(INTPTR_FORMAT " is an unallocated location "
                    "in the heap", addr);
       return;
     }
   }
   if (JNIHandles::is_global_handle((jobject) addr)) {
     st->print_cr(INTPTR_FORMAT " is a global jni handle", addr);
     return;
   }
   if (JNIHandles::is_weak_global_handle((jobject) addr)) {
     st->print_cr(INTPTR_FORMAT " is a weak global jni handle", addr);
     return;
   }
 #ifndef PRODUCT
   // we don't keep the block list in product mode
   if (JNIHandleBlock::any_contains((jobject) addr)) {
     st->print_cr(INTPTR_FORMAT " is a local jni handle", addr);
     return;
   }
 #endif
   for(JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
     // Check for privilege stack
     if (thread->privileged_stack_top() != NULL &&
         thread->privileged_stack_top()->contains(addr)) {
       st->print_cr(INTPTR_FORMAT " is pointing into the privilege stack "
                    "for thread: " INTPTR_FORMAT, addr, thread);
       if (verbose) thread->print_on(st);
       return;
     }
     // If the addr is a java thread print information about that.
     if (addr == (address)thread) {
       if (verbose) {
         thread->print_on(st);
       } else {
         st->print_cr(INTPTR_FORMAT " is a thread", addr);
       }
       return;
     }
     // If the addr is in the stack region for this thread then report that
     // and print thread info
     if (thread->stack_base() >= addr &&
         addr > (thread->stack_base() - thread->stack_size())) {
       st->print_cr(INTPTR_FORMAT " is pointing into the stack for thread: "
                    INTPTR_FORMAT, addr, thread);
       if (verbose) thread->print_on(st);
       return;
     }
   }
   // Check if in metaspace and print types that have vptrs (only method now)
   if (Metaspace::contains(addr)) {
     if (Method::has_method_vptr((const void*)addr)) {
       ((Method*)addr)->print_value_on(st);
       st->cr();
     } else {
       // Use addr->print() from the debugger instead (not here)
       st->print_cr(INTPTR_FORMAT " is pointing into metadata", addr);
     }
     return;
   }
   // Try an OS specific find
   if (os::find(addr, st)) {
     return;
   }
   st->print_cr(INTPTR_FORMAT " is an unknown value", addr);
 }
 // 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) {
 #if (defined(IA64) && !defined(AIX)) && !defined(_WIN32)
   // On IA64 we have to check if the callers bsp is still valid
   // (i.e. within the register stack bounds).
   // Notice: this only works for threads created by the VM and only if
   // we walk the current stack!!! If we want to be able to walk
   // arbitrary other threads, we'll have to somehow store the thread
   // object in the frame.
   Thread *thread = Thread::current();
   if ((address)fr->fp() <=
       thread->register_stack_base() HPUX_ONLY(+ 0x0) LINUX_ONLY(+ 0x50)) {
     // This check is a little hacky, because on Linux the first C
     // frame's ('start_thread') register stack frame starts at
     // "register_stack_base + 0x48" while on HPUX, the first C frame's
     // ('__pthread_bound_body') register stack frame seems to really
     // start at "register_stack_base".
     return true;
   } else {
     return false;
   }
 #elif defined(IA64) && defined(_WIN32)
   return true;
 #else
   // 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;
 #endif
 }
 #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, mtInternal);
     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:"
         "%/lib/jfr.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;
 }
 /*
  * Splits a path, based on its separator, the number of
  * elements is returned back in n.
  * It is the callers responsibility to:
  *   a> check the value of n, and n may be 0.
  *   b> ignore any empty path elements
  *   c> free up the data.
  */
 char** os::split_path(const char* path, int* n) {
   *n = 0;
   if (path == NULL || strlen(path) == 0) {
     return NULL;
   }
   const char psepchar = *os::path_separator();
   char* inpath = (char*)NEW_C_HEAP_ARRAY(char, strlen(path) + 1, mtInternal);
   if (inpath == NULL) {
     return NULL;
   }
   strcpy(inpath, path);
   int count = 1;
   char* p = strchr(inpath, psepchar);
   // Get a count of elements to allocate memory
   while (p != NULL) {
     count++;
     p++;
     p = strchr(p, psepchar);
   }
   char** opath = (char**) NEW_C_HEAP_ARRAY(char*, count, mtInternal);
   if (opath == NULL) {
     return NULL;
   }
   // do the actual splitting
   p = inpath;
   for (int i = 0 ; i < count ; i++) {
     size_t len = strcspn(p, os::path_separator());
     if (len > JVM_MAXPATHLEN) {
       return NULL;
     }
     // allocate the string and add terminator storage
     char* s  = (char*)NEW_C_HEAP_ARRAY(char, len + 1, mtInternal);
     if (s == NULL) {
       return NULL;
     }
     strncpy(s, p, len);
     s[len] = '\0';
     opath[i] = s;
     p += len + 1;
   }
   FREE_C_HEAP_ARRAY(char, inpath, mtInternal);
   *n = count;
   return opath;
 }
 void os::set_memory_serialize_page(address page) {
   int count = log2_intptr(sizeof(class JavaThread)) - log2_int(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)));
 }
 static volatile intptr_t SerializePageLock = 0;
 // 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 SerializePageLock 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.
   Thread::muxAcquire(&SerializePageLock, "set_memory_serialize_page");
   Thread::muxRelease(&SerializePageLock);
 }
 // 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, 'SerializePageLock' is used to block
   // the mutator thread if such case is encountered. See bug 6546278 for details.
   Thread::muxAcquire(&SerializePageLock, "serialize_thread_states");
   os::protect_memory((char *)os::get_memory_serialize_page(),
                      os::vm_page_size(), MEM_PROT_READ);
   os::protect_memory((char *)os::get_memory_serialize_page(),
                      os::vm_page_size(), MEM_PROT_RW);
   Thread::muxRelease(&SerializePageLock);
 }
 // 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 dependent 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_size, size_t min_pages, bool must_be_aligned) {
   assert(min_pages > 0, "sanity");
   if (UseLargePages) {
     const size_t max_page_size = region_size / min_pages;
     for (size_t i = 0; _page_sizes[i] != 0; ++i) {
       const size_t page_size = _page_sizes[i];
       if (page_size <= max_page_size) {
         if (!must_be_aligned || is_size_aligned(region_size, page_size)) {
           return page_size;
         }
       }
     }
   }
   return vm_page_size();
 }
 size_t os::page_size_for_region_aligned(size_t region_size, size_t min_pages) {
   return page_size_for_region(region_size, min_pages, true);
 }
 size_t os::page_size_for_region_unaligned(size_t region_size, size_t min_pages) {
   return page_size_for_region(region_size, min_pages, false);
 }
 #ifndef PRODUCT
 void os::trace_page_sizes(const char* str, const size_t* page_sizes, int count)
 {
   if (TracePageSizes) {
     tty->print("%s: ", str);
     for (int i = 0; i < count; ++i) {
       tty->print(" " SIZE_FORMAT, page_sizes[i]);
     }
     tty->cr();
   }
 }
 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;
 }
 void os::initialize_initial_active_processor_count() {
   assert(_initial_active_processor_count == 0, "Initial active processor count already set.");
   _initial_active_processor_count = active_processor_count();
 }
 void os::SuspendedThreadTask::run() {
   assert(Threads_lock->owned_by_self() || (_thread == VMThread::vm_thread()), "must have threads lock to call this");
   internal_do_task();
   _done = true;
 }
 bool os::create_stack_guard_pages(char* addr, size_t bytes) {
   return os::pd_create_stack_guard_pages(addr, bytes);
 }
 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint) {
   char* result = pd_reserve_memory(bytes, addr, alignment_hint);
   if (result != NULL) {
     MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
   }
   return result;
 }
 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint,
    MEMFLAGS flags) {
   char* result = pd_reserve_memory(bytes, addr, alignment_hint);
   if (result != NULL) {
     MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
     MemTracker::record_virtual_memory_type((address)result, flags);
   }
   return result;
 }
 char* os::attempt_reserve_memory_at(size_t bytes, char* addr) {
   char* result = pd_attempt_reserve_memory_at(bytes, addr);
   if (result != NULL) {
     MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
   }
   return result;
 }
 void os::split_reserved_memory(char *base, size_t size,
                                  size_t split, bool realloc) {
   pd_split_reserved_memory(base, size, split, realloc);
 }
 bool os::commit_memory(char* addr, size_t bytes, bool executable) {
   bool res = pd_commit_memory(addr, bytes, executable);
   if (res) {
     MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC);
   }
   return res;
 }
 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint,
                               bool executable) {
   bool res = os::pd_commit_memory(addr, size, alignment_hint, executable);
   if (res) {
     MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC);
   }
   return res;
 }
 void os::commit_memory_or_exit(char* addr, size_t bytes, bool executable,
                                const char* mesg) {
   pd_commit_memory_or_exit(addr, bytes, executable, mesg);
   MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC);
 }
 void os::commit_memory_or_exit(char* addr, size_t size, size_t alignment_hint,
                                bool executable, const char* mesg) {
   os::pd_commit_memory_or_exit(addr, size, alignment_hint, executable, mesg);
   MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC);
 }
 bool os::uncommit_memory(char* addr, size_t bytes) {
   bool res;
   if (MemTracker::tracking_level() > NMT_minimal) {
     Tracker tkr = MemTracker::get_virtual_memory_uncommit_tracker();
     res = pd_uncommit_memory(addr, bytes);
     if (res) {
       tkr.record((address)addr, bytes);
     }
   } else {
     res = pd_uncommit_memory(addr, bytes);
   }
   return res;
 }
 bool os::release_memory(char* addr, size_t bytes) {
   bool res;
   if (MemTracker::tracking_level() > NMT_minimal) {
     Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
     res = pd_release_memory(addr, bytes);
     if (res) {
       tkr.record((address)addr, bytes);
     }
   } else {
     res = pd_release_memory(addr, bytes);
   }
   return res;
 }
 void os::pretouch_memory(char* start, char* end) {
   for (volatile char *p = start; p < end; p += os::vm_page_size()) {
     *p = 0;
   }
 }
 char* os::map_memory(int fd, const char* file_name, size_t file_offset,
                            char *addr, size_t bytes, bool read_only,
                            bool allow_exec) {
   char* result = pd_map_memory(fd, file_name, file_offset, addr, bytes, read_only, allow_exec);
   if (result != NULL) {
     MemTracker::record_virtual_memory_reserve_and_commit((address)result, bytes, CALLER_PC);
   }
   return result;
 }
 char* os::remap_memory(int fd, const char* file_name, size_t file_offset,
                              char *addr, size_t bytes, bool read_only,
                              bool allow_exec) {
   return pd_remap_memory(fd, file_name, file_offset, addr, bytes,
                     read_only, allow_exec);
 }
 bool os::unmap_memory(char *addr, size_t bytes) {
   bool result;
   if (MemTracker::tracking_level() > NMT_minimal) {
     Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
     result = pd_unmap_memory(addr, bytes);
     if (result) {
       tkr.record((address)addr, bytes);
     }
   } else {
     result = pd_unmap_memory(addr, bytes);
   }
   return result;
 }
 void os::free_memory(char *addr, size_t bytes, size_t alignment_hint) {
   pd_free_memory(addr, bytes, alignment_hint);
 }
 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
   pd_realign_memory(addr, bytes, alignment_hint);
 }
 #ifndef TARGET_OS_FAMILY_windows
 /* try to switch state from state "from" to state "to"
  * returns the state set after the method is complete
  */
 os::SuspendResume::State os::SuspendResume::switch_state(os::SuspendResume::State from,
                                                          os::SuspendResume::State to)
 {
   os::SuspendResume::State result =
     (os::SuspendResume::State) Atomic::cmpxchg((jint) to, (jint *) &_state, (jint) from);
   if (result == from) {
     // success
     return to;
   }
   return result;
 }
 #endif
 /////////////// Unit tests ///////////////
 #ifndef PRODUCT
 #define assert_eq(a,b) assert(a == b, err_msg(SIZE_FORMAT " != " SIZE_FORMAT, a, b))
 class TestOS : AllStatic {
   static size_t small_page_size() {
     return os::vm_page_size();
   }
   static size_t large_page_size() {
     const size_t large_page_size_example = 4 * M;
     return os::page_size_for_region_aligned(large_page_size_example, 1);
   }
   static void test_page_size_for_region_aligned() {
     if (UseLargePages) {
       const size_t small_page = small_page_size();
       const size_t large_page = large_page_size();
       if (large_page > small_page) {
         size_t num_small_pages_in_large = large_page / small_page;
         size_t page = os::page_size_for_region_aligned(large_page, num_small_pages_in_large);
         assert_eq(page, small_page);
       }
     }
   }
   static void test_page_size_for_region_alignment() {
     if (UseLargePages) {
       const size_t small_page = small_page_size();
       const size_t large_page = large_page_size();
       if (large_page > small_page) {
         const size_t unaligned_region = large_page + 17;
         size_t page = os::page_size_for_region_aligned(unaligned_region, 1);
         assert_eq(page, small_page);
         const size_t num_pages = 5;
         const size_t aligned_region = large_page * num_pages;
         page = os::page_size_for_region_aligned(aligned_region, num_pages);
         assert_eq(page, large_page);
       }
     }
   }
   static void test_page_size_for_region_unaligned() {
     if (UseLargePages) {
       // Given exact page size, should return that page size.
       for (size_t i = 0; os::_page_sizes[i] != 0; i++) {
         size_t expected = os::_page_sizes[i];
         size_t actual = os::page_size_for_region_unaligned(expected, 1);
         assert_eq(expected, actual);
       }
       // Given slightly larger size than a page size, return the page size.
       for (size_t i = 0; os::_page_sizes[i] != 0; i++) {
         size_t expected = os::_page_sizes[i];
         size_t actual = os::page_size_for_region_unaligned(expected + 17, 1);
         assert_eq(expected, actual);
       }
       // Given a slightly smaller size than a page size,
       // return the next smaller page size.
       if (os::_page_sizes[1] > os::_page_sizes[0]) {
         size_t expected = os::_page_sizes[0];
         size_t actual = os::page_size_for_region_unaligned(os::_page_sizes[1] - 17, 1);
         assert_eq(actual, expected);
       }
       // Return small page size for values less than a small page.
       size_t small_page = small_page_size();
       size_t actual = os::page_size_for_region_unaligned(small_page - 17, 1);
       assert_eq(small_page, actual);
     }
   }
  public:
   static void run_tests() {
     test_page_size_for_region_aligned();
     test_page_size_for_region_alignment();
     test_page_size_for_region_unaligned();
   }
 };
 void TestOS_test() {
   TestOS::run_tests();
 }
 #endif // PRODUCT

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src/share/vm/runtime/os.cpp@72053ed6f8d4 (annotated)

src/share/vm/runtime/os.cpp