Merge

src/os/windows/vm/os_windows.cpp

 /*
- * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2016, 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
@@ -1747,8 +1747,7 @@ void os::win32::print_windows_version(outputStream* st) {
     if (is_workstation) {
       st->print("10");
     } else {
-      // The server version name of Windows 10 is not known at this time
-      st->print("%d.%d", major_version, minor_version);
+      st->print("Server 2016");
     }
     break;
 

src/share/vm/gc_implementation/g1/concurrentMark.cpp

 /*
- * Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2016, 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
@@ -631,11 +631,10 @@ ConcurrentMark::ConcurrentMark(G1CollectedHeap* g1h, G1RegionToSpaceMapper* prev
       double overall_cm_overhead =
         (double) MaxGCPauseMillis * marking_overhead /
         (double) GCPauseIntervalMillis;
-      double cpu_ratio = 1.0 / (double) os::processor_count();
+      double cpu_ratio = 1.0 / os::initial_active_processor_count();
       double marking_thread_num = ceil(overall_cm_overhead / cpu_ratio);
       double marking_task_overhead =
-        overall_cm_overhead / marking_thread_num *
-                                                (double) os::processor_count();
+        overall_cm_overhead / marking_thread_num * os::initial_active_processor_count();
       double sleep_factor =
                          (1.0 - marking_task_overhead) / marking_task_overhead;
 

src/share/vm/gc_implementation/g1/dirtyCardQueue.cpp

 /*
- * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2016, 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
@@ -80,7 +80,7 @@ DirtyCardQueueSet::DirtyCardQueueSet(bool notify_when_complete) :
 
 // Determines how many mutator threads can process the buffers in parallel.
 uint DirtyCardQueueSet::num_par_ids() {
-  return (uint)os::processor_count();
+  return (uint)os::initial_active_processor_count();
 }
 
 void DirtyCardQueueSet::initialize(CardTableEntryClosure* cl, Monitor* cbl_mon, Mutex* fl_lock,

src/share/vm/gc_implementation/parNew/parCardTableModRefBS.cpp

@@ -452,9 +452,13 @@ get_LNC_array_for_space(Space* sp,
   // event lock and do the read again in case some other thread had already
   // succeeded and done the resize.
   int cur_collection = Universe::heap()->total_collections();
-  if (_last_LNC_resizing_collection[i] != cur_collection) {
+  // Updated _last_LNC_resizing_collection[i] must not be visible before
+  // _lowest_non_clean and friends are visible. Therefore use acquire/release
+  // to guarantee this on non TSO architecures.
+  if (OrderAccess::load_acquire(&_last_LNC_resizing_collection[i]) != cur_collection) {
     MutexLocker x(ParGCRareEvent_lock);
-    if (_last_LNC_resizing_collection[i] != cur_collection) {
+    // This load_acquire is here for clarity only. The MutexLocker already fences.
+    if (OrderAccess::load_acquire(&_last_LNC_resizing_collection[i]) != cur_collection) {
       if (_lowest_non_clean[i] == NULL ||
           n_chunks != _lowest_non_clean_chunk_size[i]) {
 
@@ -474,7 +478,8 @@ get_LNC_array_for_space(Space* sp,
             _lowest_non_clean[i][j] = NULL;
         }
       }
-      _last_LNC_resizing_collection[i] = cur_collection;
+      // Make sure this gets visible only after _lowest_non_clean* was initialized
+      OrderAccess::release_store(&_last_LNC_resizing_collection[i], cur_collection);
     }
   }
   // In any case, now do the initialization.

src/share/vm/memory/cardTableModRefBS.hpp

@@ -217,7 +217,7 @@ class CardTableModRefBS: public ModRefBarrierSet {
   CardArr* _lowest_non_clean;
   size_t*  _lowest_non_clean_chunk_size;
   uintptr_t* _lowest_non_clean_base_chunk_index;
-  int* _last_LNC_resizing_collection;
+  volatile int* _last_LNC_resizing_collection;
 
   // Initializes "lowest_non_clean" to point to the array for the region
   // covering "sp", and "lowest_non_clean_base_chunk_index" to the chunk

src/share/vm/runtime/os.cpp

 /*
- * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2016, 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
@@ -78,6 +78,7 @@ 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
@@ -322,6 +323,7 @@ static void signal_thread_entry(JavaThread* thread, TRAPS) {
 }
 
 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();
@@ -835,7 +837,11 @@ void os::print_cpu_info(outputStream* st) {
   st->print("CPU:");
   st->print("total %d", os::processor_count());
   // It's not safe to query number of active processors after crash
-  // st->print("(active %d)", os::active_processor_count());
+  // st->print("(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);
@@ -1418,6 +1424,11 @@ bool os::is_server_class_machine() {
   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();

src/share/vm/runtime/os.hpp

@@ -151,6 +151,7 @@ class os: AllStatic {
 
   static size_t page_size_for_region(size_t region_size, size_t min_pages, bool must_be_aligned);
 
+  static void initialize_initial_active_processor_count();
  public:
   static void init(void);                      // Called before command line parsing
   static void init_before_ergo(void);          // Called after command line parsing
@@ -238,6 +239,13 @@ class os: AllStatic {
   // Note that on some OSes this can change dynamically.
   static int active_processor_count();
 
+  // At startup the number of active CPUs this process is allowed to run on.
+  // This value does not change dynamically. May be different from active_processor_count().
+  static int initial_active_processor_count() {
+    assert(_initial_active_processor_count > 0, "Initial active processor count not set yet.");
+    return _initial_active_processor_count;
+  }
+
   // Bind processes to processors.
   //     This is a two step procedure:
   //     first you generate a distribution of processes to processors,
@@ -975,8 +983,9 @@ class os: AllStatic {
 
 
  protected:
-  static long _rand_seed;                   // seed for random number generator
-  static int _processor_count;              // number of processors
+  static long _rand_seed;                     // seed for random number generator
+  static int _processor_count;                // number of processors
+  static int _initial_active_processor_count; // number of active processors during initialization.
 
   static char* format_boot_path(const char* format_string,
                                 const char* home,

src/share/vm/runtime/vm_version.cpp

 /*
- * Copyright (c) 1998, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2016, 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
@@ -296,7 +296,7 @@ unsigned int Abstract_VM_Version::nof_parallel_worker_threads(
     // processor after the first 8.  For example, on a 72 cpu machine
     // and a chosen fraction of 5/8
     // use 8 + (72 - 8) * (5/8) == 48 worker threads.
-    unsigned int ncpus = (unsigned int) os::active_processor_count();
+    unsigned int ncpus = (unsigned int) os::initial_active_processor_count();
     return (ncpus <= switch_pt) ?
            ncpus :
           (switch_pt + ((ncpus - switch_pt) * num) / den);