# HG changeset patch
# User mdoerr
# Date 1563185053 -7200
#      Mon Jul 15 12:04:13 2019 +0200
# Node ID ecca61fb559db5b6bfc56cf7c9985ec621f38ba5
# Parent  4b1de39beda387d953075384e8b36186b6e73dfd
8227597: [fastdbg build] Arena::inc_bytes_allocated should get inlined
Reviewed-by: mbaesken, goetz

diff --git a/src/hotspot/share/memory/allocation.inline.hpp b/src/hotspot/share/memory/allocation.inline.hpp
--- a/src/hotspot/share/memory/allocation.inline.hpp
+++ b/src/hotspot/share/memory/allocation.inline.hpp
@@ -34,16 +34,13 @@
 // Explicit C-heap memory management
 
 #ifndef PRODUCT
-// Increments unsigned long value for statistics (not atomic on MP).
+// Increments unsigned long value for statistics (not atomic on MP, but avoids word-tearing on 32 bit).
 inline void inc_stat_counter(volatile julong* dest, julong add_value) {
-#if defined(SPARC) || defined(X86)
-  // Sparc and X86 have atomic jlong (8 bytes) instructions
+#ifdef _LP64
+  *dest += add_value;
+#else
   julong value = Atomic::load(dest);
-  value += add_value;
-  Atomic::store(value, dest);
-#else
-  // possible word-tearing during load/store
-  *dest += add_value;
+  Atomic::store(value + add_value, dest);
 #endif
 }
 #endif
diff --git a/src/hotspot/share/memory/arena.cpp b/src/hotspot/share/memory/arena.cpp
--- a/src/hotspot/share/memory/arena.cpp
+++ b/src/hotspot/share/memory/arena.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2017, 2019, 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
@@ -477,8 +477,6 @@
 
 julong Arena::_bytes_allocated = 0;
 
-void Arena::inc_bytes_allocated(size_t x) { inc_stat_counter(&_bytes_allocated, x); }
-
 // debugging code
 inline void Arena::free_all(char** start, char** end) {
   for (char** p = start; p < end; p++) if (*p) os::free(*p);
diff --git a/src/hotspot/share/memory/arena.hpp b/src/hotspot/share/memory/arena.hpp
--- a/src/hotspot/share/memory/arena.hpp
+++ b/src/hotspot/share/memory/arena.hpp
@@ -26,6 +26,7 @@
 #define SHARE_MEMORY_ARENA_HPP
 
 #include "memory/allocation.hpp"
+#include "runtime/atomic.hpp"
 #include "runtime/globals.hpp"
 #include "utilities/globalDefinitions.hpp"
 
@@ -106,11 +107,25 @@
   void* grow(size_t x, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
   size_t _size_in_bytes;        // Size of arena (used for native memory tracking)
 
-  NOT_PRODUCT(static julong _bytes_allocated;) // total #bytes allocated since start
+#ifndef PRODUCT
+  static julong _bytes_allocated; // total #bytes allocated since start
+  // Inlinable increment function (not atomic on MP, but avoids word-tearing on 32 bit)
+  void inc_bytes_allocated(size_t x) {
+    // Only do it if needed. Otherwise avoid contention.
+    if (PrintMallocStatistics) {
+#ifdef _LP64
+      _bytes_allocated += x;
+#else
+      julong value = Atomic::load(&_bytes_allocated);
+      Atomic::store(value + x, &_bytes_allocated);
+#endif
+    }
+  }
+#endif
+
   friend class AllocStats;
   debug_only(void* malloc(size_t size);)
   debug_only(void* internal_malloc_4(size_t x);)
-  NOT_PRODUCT(void inc_bytes_allocated(size_t x);)
 
   void signal_out_of_memory(size_t request, const char* whence) const;