src/share/vm/prims/unsafe.cpp

rev 10065 : imported patch unsafecopyswap
rev 10066 : imported patch unsafecopyswap2

*** 1,7 ****
  /*
!  * Copyright (c) 2000, 2015, 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.
--- 1,7 ----
  /*
!  * Copyright (c) 2000, 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
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
*** 658,667 ****
--- 658,697 ----
    void* src = index_oop_from_field_offset_long(srcp, srcOffset);
    void* dst = index_oop_from_field_offset_long(dstp, dstOffset);
    Copy::conjoint_memory_atomic(src, dst, sz);
  UNSAFE_END
  
+ // This function is a leaf since if the source and destination are both in native memory
+ // the copy may potentially be very large, and we don't want to disable GC if we can avoid it.
+ // If either source or destination (or both) are on the heap, the function will enter VM using
+ // JVM_ENTRY_FROM_LEAF
+ JVM_LEAF(void, Unsafe_CopySwapMemory0(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size, jlong elemSize)) {
+   UnsafeWrapper("Unsafe_CopySwapMemory0");
+ 
+   size_t sz = (size_t)size;
+   size_t esz = (size_t)elemSize;
+ 
+   if (srcObj == NULL && dstObj == NULL) {
+     // Both src & dst are in native memory
+     address src = (address)srcOffset;
+     address dst = (address)dstOffset;
+ 
+     Copy::conjoint_swap(src, dst, sz, esz);
+   } else {
+     // At least one of src/dst are on heap, transition to VM to access raw pointers
+ 
+     JVM_ENTRY_FROM_LEAF(env, void, Unsafe_CopySwapMemory0) {
+       oop srcp = JNIHandles::resolve(srcObj);
+       oop dstp = JNIHandles::resolve(dstObj);
+ 
+       address src = (address)index_oop_from_field_offset_long(srcp, srcOffset);
+       address dst = (address)index_oop_from_field_offset_long(dstp, dstOffset);
+ 
+       Copy::conjoint_swap(src, dst, sz, esz);
+     } JVM_END
+   }
+ } JVM_END
  
  ////// Random queries
  
  // See comment at file start about UNSAFE_LEAF
  //UNSAFE_LEAF(jint, Unsafe_AddressSize())
*** 1361,1370 ****
--- 1391,1401 ----
      {CC "unpark",             CC "(" OBJ ")V",           FN_PTR(Unsafe_Unpark)},
  
      {CC "getLoadAverage",     CC "([DI)I",               FN_PTR(Unsafe_Loadavg)},
  
      {CC "copyMemory",         CC "(" OBJ "J" OBJ "JJ)V", FN_PTR(Unsafe_CopyMemory)},
+     {CC "copySwapMemory0",    CC "(" OBJ "J" OBJ "JJJ)V", FN_PTR(Unsafe_CopySwapMemory0)},
      {CC "setMemory",          CC "(" OBJ "JJB)V",        FN_PTR(Unsafe_SetMemory)},
  
      {CC "defineAnonymousClass", CC "(" DAC_Args ")" CLS, FN_PTR(Unsafe_DefineAnonymousClass)},
  
      {CC "shouldBeInitialized",CC "(" CLS ")Z",           FN_PTR(Unsafe_ShouldBeInitialized)},