diff --git a/src/os_cpu/bsd_x86/vm/globals_bsd_x86.hpp b/src/os_cpu/bsd_x86/vm/globals_bsd_x86.hpp
index 1144115bc5ed9cf19c7205f180c443b7ce8b7b49..0da430230a8d42d47fb78b2ae335920cdc080770 100644
--- a/src/os_cpu/bsd_x86/vm/globals_bsd_x86.hpp
+++ b/src/os_cpu/bsd_x86/vm/globals_bsd_x86.hpp
@@ -46,7 +46,7 @@ define_pd_global(uintx, SurvivorRatio,           8);
 
 define_pd_global(uintx, JVMInvokeMethodSlack,    8192);
 
-// Used on 64 bit platforms for UseCompressedOops base address or CDS
+// Used on 64 bit platforms for UseCompressedOops base address
 define_pd_global(uintx, HeapBaseMinAddress,      2*G);
 
 #endif // OS_CPU_BSD_X86_VM_GLOBALS_BSD_X86_HPP
diff --git a/src/os_cpu/bsd_zero/vm/globals_bsd_zero.hpp b/src/os_cpu/bsd_zero/vm/globals_bsd_zero.hpp
index 9c988eb743b9a1505209941fdfc7fc6f4b126044..44f72df22cf788f55511b088e5ca69f2b4e642d7 100644
--- a/src/os_cpu/bsd_zero/vm/globals_bsd_zero.hpp
+++ b/src/os_cpu/bsd_zero/vm/globals_bsd_zero.hpp
@@ -41,7 +41,7 @@ define_pd_global(intx,  VMThreadStackSize,       512);
 define_pd_global(intx,  CompilerThreadStackSize, 0);
 define_pd_global(uintx, JVMInvokeMethodSlack,    8192);
 
-// Used on 64 bit platforms for UseCompressedOops base address or CDS
+// Used on 64 bit platforms for UseCompressedOops base address
 define_pd_global(uintx, HeapBaseMinAddress,      2*G);
 
 #endif // OS_CPU_BSD_ZERO_VM_GLOBALS_BSD_ZERO_HPP
diff --git a/src/os_cpu/linux_sparc/vm/globals_linux_sparc.hpp b/src/os_cpu/linux_sparc/vm/globals_linux_sparc.hpp
index 4ac5ead19461f8f6c64799d54a7cec7edeb05b64..844279e41e0a0f3ec7883586632c5498939623fb 100644
--- a/src/os_cpu/linux_sparc/vm/globals_linux_sparc.hpp
+++ b/src/os_cpu/linux_sparc/vm/globals_linux_sparc.hpp
@@ -33,7 +33,7 @@
 define_pd_global(uintx, JVMInvokeMethodSlack,    12288);
 define_pd_global(intx, CompilerThreadStackSize,  0);
 
-// Used on 64 bit platforms for UseCompressedOops base address or CDS
+// Used on 64 bit platforms for UseCompressedOops base address
 define_pd_global(uintx, HeapBaseMinAddress,      CONST64(4)*G);
 
 #endif // OS_CPU_LINUX_SPARC_VM_GLOBALS_LINUX_SPARC_HPP
diff --git a/src/os_cpu/linux_x86/vm/globals_linux_x86.hpp b/src/os_cpu/linux_x86/vm/globals_linux_x86.hpp
index b11a6f3aa276aaa5eee24047d5a56d0807cea476..622928aa17bf3ca4817f6a6d5f3c79e29f9e1f63 100644
--- a/src/os_cpu/linux_x86/vm/globals_linux_x86.hpp
+++ b/src/os_cpu/linux_x86/vm/globals_linux_x86.hpp
@@ -44,7 +44,7 @@ define_pd_global(intx, CompilerThreadStackSize,  0);
 
 define_pd_global(uintx,JVMInvokeMethodSlack,     8192);
 
-// Used on 64 bit platforms for UseCompressedOops base address or CDS
+// Used on 64 bit platforms for UseCompressedOops base address
 define_pd_global(uintx,HeapBaseMinAddress,       2*G);
 
 #endif // OS_CPU_LINUX_X86_VM_GLOBALS_LINUX_X86_HPP
diff --git a/src/os_cpu/linux_zero/vm/globals_linux_zero.hpp b/src/os_cpu/linux_zero/vm/globals_linux_zero.hpp
index 56495d176d1d1b1812ac912a77842edd63412be7..4e0be5c79f32baef1e2f4b85c1ed3d9cfea9d6b2 100644
--- a/src/os_cpu/linux_zero/vm/globals_linux_zero.hpp
+++ b/src/os_cpu/linux_zero/vm/globals_linux_zero.hpp
@@ -41,7 +41,7 @@ define_pd_global(intx,  VMThreadStackSize,       512);
 define_pd_global(intx,  CompilerThreadStackSize, 0);
 define_pd_global(uintx, JVMInvokeMethodSlack,    8192);
 
-// Used on 64 bit platforms for UseCompressedOops base address or CDS
+// Used on 64 bit platforms for UseCompressedOops base address
 define_pd_global(uintx, HeapBaseMinAddress,      2*G);
 
 #endif // OS_CPU_LINUX_ZERO_VM_GLOBALS_LINUX_ZERO_HPP
diff --git a/src/os_cpu/solaris_sparc/vm/globals_solaris_sparc.hpp b/src/os_cpu/solaris_sparc/vm/globals_solaris_sparc.hpp
index e6cb0dddb01c9bb50ec841121d8466ea119950a1..595cd781447d4bc4d60a8b1c56251046b75ad310 100644
--- a/src/os_cpu/solaris_sparc/vm/globals_solaris_sparc.hpp
+++ b/src/os_cpu/solaris_sparc/vm/globals_solaris_sparc.hpp
@@ -33,7 +33,7 @@
 define_pd_global(uintx, JVMInvokeMethodSlack,    12288);
 define_pd_global(intx, CompilerThreadStackSize,  0);
 
-// Used on 64 bit platforms for UseCompressedOops base address or CDS
+// Used on 64 bit platforms for UseCompressedOops base address
 #ifdef _LP64
 define_pd_global(uintx, HeapBaseMinAddress,      CONST64(4)*G);
 #else
diff --git a/src/os_cpu/solaris_x86/vm/globals_solaris_x86.hpp b/src/os_cpu/solaris_x86/vm/globals_solaris_x86.hpp
index 5d99a09c447c83334543551dfeaefe318db54e3f..91a4336d9035554bd721d70f385516a79a268c03 100644
--- a/src/os_cpu/solaris_x86/vm/globals_solaris_x86.hpp
+++ b/src/os_cpu/solaris_x86/vm/globals_solaris_x86.hpp
@@ -43,7 +43,7 @@ define_pd_global(uintx,JVMInvokeMethodSlack,     10*K);
 
 define_pd_global(intx, CompilerThreadStackSize,  0);
 
-// Used on 64 bit platforms for UseCompressedOops base address or CDS
+// Used on 64 bit platforms for UseCompressedOops base address
 define_pd_global(uintx,HeapBaseMinAddress,       256*M);
 
 #endif // OS_CPU_SOLARIS_X86_VM_GLOBALS_SOLARIS_X86_HPP
diff --git a/src/os_cpu/windows_x86/vm/globals_windows_x86.hpp b/src/os_cpu/windows_x86/vm/globals_windows_x86.hpp
index f4167f5eb5ca6f661cce1db997a9e36d283bca74..10e0aaff7472af929681e09b981c9bb53be50163 100644
--- a/src/os_cpu/windows_x86/vm/globals_windows_x86.hpp
+++ b/src/os_cpu/windows_x86/vm/globals_windows_x86.hpp
@@ -45,7 +45,7 @@ define_pd_global(intx, CompilerThreadStackSize,  0);
 
 define_pd_global(uintx, JVMInvokeMethodSlack,    8192);
 
-// Used on 64 bit platforms for UseCompressedOops base address or CDS
+// Used on 64 bit platforms for UseCompressedOops base address
 define_pd_global(uintx, HeapBaseMinAddress,      2*G);
 
 #endif // OS_CPU_WINDOWS_X86_VM_GLOBALS_WINDOWS_X86_HPP
diff --git a/src/share/vm/memory/filemap.cpp b/src/share/vm/memory/filemap.cpp
index fec0957f145d71f84997bc9a1b36ff43e607fa06..133685932fd430bb89e8a984a0c6eddeea787df9 100644
--- a/src/share/vm/memory/filemap.cpp
+++ b/src/share/vm/memory/filemap.cpp
@@ -372,7 +372,7 @@ ReservedSpace FileMapInfo::reserve_shared_memory() {
   // other reserved memory (like the code cache).
   ReservedSpace rs(size, alignment, false, requested_addr);
   if (!rs.is_reserved()) {
-    fail_continue(err_msg("Unable to reserved shared space at required address " INTPTR_FORMAT, requested_addr));
+    fail_continue(err_msg("Unable to reserve shared space at required address " INTPTR_FORMAT, requested_addr));
     return rs;
   }
   // the reserved virtual memory is for mapping class data sharing archive
diff --git a/src/share/vm/memory/metaspace.cpp b/src/share/vm/memory/metaspace.cpp
index 6e3145dfac5efe6628e03307d24376643aa4320b..47cbeaa19ed419bf2f207f94557ff9108590bd40 100644
--- a/src/share/vm/memory/metaspace.cpp
+++ b/src/share/vm/memory/metaspace.cpp
@@ -337,27 +337,16 @@ VirtualSpaceNode::VirtualSpaceNode(size_t byte_size) : _top(NULL), _next(NULL),
   // align up to vm allocation granularity
   byte_size = align_size_up(byte_size, os::vm_allocation_granularity());
 
-  // This allocates memory with mmap.  For DumpSharedspaces, allocate the
-  // space at low memory so that other shared images don't conflict.
-  // This is the same address as memory needed for UseCompressedOops but
-  // compressed oops don't work with CDS (offsets in metadata are wrong), so
-  // borrow the same address.
+  // This allocates memory with mmap.  For DumpSharedspaces, try to reserve
+  // configurable address, generally at the top of the Java heap so other
+  // memory addresses don't conflict.
   if (DumpSharedSpaces) {
-    char* shared_base = (char*)HeapBaseMinAddress;
+    char* shared_base = (char*)SharedBaseAddress;
     _rs = ReservedSpace(byte_size, 0, false, shared_base, 0);
     if (_rs.is_reserved()) {
-      assert(_rs.base() == shared_base, "should match");
+      assert(shared_base == 0 || _rs.base() == shared_base, "should match");
     } else {
-      // If we are dumping the heap, then allocate a wasted block of address
-      // space in order to push the heap to a lower address.  This extra
-      // address range allows for other (or larger) libraries to be loaded
-      // without them occupying the space required for the shared spaces.
-      uintx reserved = 0;
-      uintx block_size = 64*1024*1024;
-      while (reserved < SharedDummyBlockSize) {
-        char* dummy = os::reserve_memory(block_size);
-        reserved += block_size;
-      }
+      // Get a mmap region anywhere if the SharedBaseAddress fails.
       _rs = ReservedSpace(byte_size);
     }
     MetaspaceShared::set_shared_rs(&_rs);
diff --git a/src/share/vm/runtime/globals.hpp b/src/share/vm/runtime/globals.hpp
index 489999f6c4a49c60634e6d188f4d7f15e40e2bac..7a8dd4a436e290ca2ae5d4884d66936db0c63f8e 100644
--- a/src/share/vm/runtime/globals.hpp
+++ b/src/share/vm/runtime/globals.hpp
@@ -3573,8 +3573,9 @@ class CommandLineFlags {
   product(uintx, SharedMiscCodeSize,    120*K,                              \
           "Size of the shared miscellaneous code area (in bytes)")          \
                                                                             \
-  product(uintx, SharedDummyBlockSize, 0,                                   \
-          "Size of dummy block used to shift heap addresses (in bytes)")    \
+  product(uintx, SharedBaseAddress, LP64_ONLY(32*G)                         \
+          NOT_LP64(LINUX_ONLY(2*G) NOT_LINUX(0)),                           \
+          "Address to allocate shared memory region for class data")        \
                                                                             \
   diagnostic(bool, EnableInvokeDynamic, true,                               \
           "support JSR 292 (method handles, invokedynamic, "                \