8000968: NPG: UseCompressedKlassPointers asserts with ObjectAlignmentInBytes...

8000968: NPG: UseCompressedKlassPointers asserts with ObjectAlignmentInBytes for > 32G CompressedOops
Summary: Pick a base that works for both CompressedOpps alignment and CompressedKlassPtrs alignment.
Reviewed-by: kvn, roland

src/share/vm/memory/universe.cpp

@@ -144,6 +144,7 @@ NarrowPtrStruct Universe::_narrow_oop = { NULL, 0, true };
 NarrowPtrStruct Universe::_narrow_klass = { NULL, 0, true };
 address Universe::_narrow_ptrs_base;
 
+size_t          Universe::_class_metaspace_size;
 
 void Universe::basic_type_classes_do(void f(Klass*)) {
   f(boolArrayKlassObj());
@@ -689,8 +690,15 @@ char* Universe::preferred_heap_base(size_t heap_size, NARROW_OOP_MODE mode) {
     // Return specified base for the first request.
     if (!FLAG_IS_DEFAULT(HeapBaseMinAddress) && (mode == UnscaledNarrowOop)) {
       base = HeapBaseMinAddress;
-    } else if (total_size <= OopEncodingHeapMax && (mode != HeapBasedNarrowOop)) {
-      if (total_size <= NarrowOopHeapMax && (mode == UnscaledNarrowOop) &&
+
+    // If the total size and the metaspace size are small enough to allow
+    // UnscaledNarrowOop then just use UnscaledNarrowOop.
+    } else if ((total_size <= OopEncodingHeapMax) && (mode != HeapBasedNarrowOop) &&
+        (!UseCompressedKlassPointers ||
+          (((OopEncodingHeapMax - heap_size) + Universe::class_metaspace_size()) <= KlassEncodingMetaspaceMax))) {
+      // We don't need to check the metaspace size here because it is always smaller
+      // than total_size.
+      if ((total_size <= NarrowOopHeapMax) && (mode == UnscaledNarrowOop) &&
           (Universe::narrow_oop_shift() == 0)) {
         // Use 32-bits oops without encoding and
         // place heap's top on the 4Gb boundary
@@ -706,14 +714,24 @@ char* Universe::preferred_heap_base(size_t heap_size, NARROW_OOP_MODE mode) {
           base = (OopEncodingHeapMax - heap_size);
         }
       }
+
+    // See if ZeroBaseNarrowOop encoding will work for a heap based at
+    // (KlassEncodingMetaspaceMax - class_metaspace_size()).
+    } else if (UseCompressedKlassPointers && (mode != HeapBasedNarrowOop) &&
+        (Universe::class_metaspace_size() + HeapBaseMinAddress <= KlassEncodingMetaspaceMax) &&
+        (KlassEncodingMetaspaceMax + heap_size - Universe::class_metaspace_size() <= OopEncodingHeapMax)) {
+      base = (KlassEncodingMetaspaceMax - Universe::class_metaspace_size());
     } else {
-      // Can't reserve below 32Gb.
+      // UnscaledNarrowOop encoding didn't work, and no base was found for ZeroBasedOops or
+      // HeapBasedNarrowOop encoding was requested.  So, can't reserve below 32Gb.
       Universe::set_narrow_oop_shift(LogMinObjAlignmentInBytes);
     }
+
     // Set narrow_oop_base and narrow_oop_use_implicit_null_checks
     // used in ReservedHeapSpace() constructors.
     // The final values will be set in initialize_heap() below.
-    if (base != 0 && (base + heap_size) <= OopEncodingHeapMax) {
+    if ((base != 0) && ((base + heap_size) <= OopEncodingHeapMax) &&
+        (!UseCompressedKlassPointers || (base + Universe::class_metaspace_size()) <= KlassEncodingMetaspaceMax)) {
       // Use zero based compressed oops
       Universe::set_narrow_oop_base(NULL);
       // Don't need guard page for implicit checks in indexed
@@ -796,7 +814,9 @@ jint Universe::initialize_heap() {
       tty->print("heap address: " PTR_FORMAT ", size: " SIZE_FORMAT " MB",
                  Universe::heap()->base(), Universe::heap()->reserved_region().byte_size()/M);
     }
-    if ((uint64_t)Universe::heap()->reserved_region().end() > OopEncodingHeapMax) {
+    if (((uint64_t)Universe::heap()->reserved_region().end() > OopEncodingHeapMax) ||
+        (UseCompressedKlassPointers &&
+        ((uint64_t)Universe::heap()->base() + Universe::class_metaspace_size() > KlassEncodingMetaspaceMax))) {
       // Can't reserve heap below 32Gb.
       // keep the Universe::narrow_oop_base() set in Universe::reserve_heap()
       Universe::set_narrow_oop_shift(LogMinObjAlignmentInBytes);
@@ -862,8 +882,8 @@ ReservedSpace Universe::reserve_heap(size_t heap_size, size_t alignment) {
   // be compressed the same as instances.
   // Need to round class space size up because it's below the heap and
   // the actual alignment depends on its size.
-  size_t metaspace_size = align_size_up(ClassMetaspaceSize, alignment);
-  size_t total_reserved = align_size_up(heap_size + metaspace_size, alignment);
+  Universe::set_class_metaspace_size(align_size_up(ClassMetaspaceSize, alignment));
+  size_t total_reserved = align_size_up(heap_size + Universe::class_metaspace_size(), alignment);
   char* addr = Universe::preferred_heap_base(total_reserved, Universe::UnscaledNarrowOop);
 
   ReservedHeapSpace total_rs(total_reserved, alignment, UseLargePages, addr);
@@ -904,8 +924,8 @@ ReservedSpace Universe::reserve_heap(size_t heap_size, size_t alignment) {
   // compressed oops is greater than the one used for compressed klass
   // ptrs, a metadata space on top of the heap could become
   // unreachable.
-  ReservedSpace class_rs = total_rs.first_part(metaspace_size);
-  ReservedSpace heap_rs = total_rs.last_part(metaspace_size, alignment);
+  ReservedSpace class_rs = total_rs.first_part(Universe::class_metaspace_size());
+  ReservedSpace heap_rs = total_rs.last_part(Universe::class_metaspace_size(), alignment);
   Metaspace::initialize_class_space(class_rs);
 
   if (UseCompressedOops) {

src/share/vm/memory/universe.hpp

 /*
- * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2013, 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
@@ -211,6 +211,9 @@ class Universe: AllStatic {
   static struct NarrowPtrStruct _narrow_klass;
   static address _narrow_ptrs_base;
 
+  // Aligned size of the metaspace.
+  static size_t _class_metaspace_size;
+
   // array of dummy objects used with +FullGCAlot
   debug_only(static objArrayOop _fullgc_alot_dummy_array;)
   // index of next entry to clear
@@ -278,6 +281,13 @@ class Universe: AllStatic {
   static bool     reserve_metaspace_helper(bool with_base = false);
   static ReservedHeapSpace reserve_heap_metaspace(size_t heap_size, size_t alignment, bool& contiguous);
 
+  static size_t  class_metaspace_size() {
+    return _class_metaspace_size;
+  }
+  static void    set_class_metaspace_size(size_t metaspace_size) {
+    _class_metaspace_size = metaspace_size;
+  }
+
   // Debugging
   static int _verify_count;                           // number of verifies done
   // True during call to verify().  Should only be set/cleared in verify().

src/share/vm/oops/oop.inline.hpp

 /*
- * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2013, 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
@@ -227,12 +227,12 @@ inline oop oopDesc::decode_heap_oop(oop v)  { return v; }
 // might not be the same as oop.
 
 inline narrowOop oopDesc::encode_klass_not_null(Klass* v) {
-  assert(!is_null(v), "oop value can never be zero");
+  assert(!is_null(v), "klass value can never be zero");
   assert(check_klass_alignment(v), "Address not aligned");
   address base = Universe::narrow_klass_base();
   int    shift = Universe::narrow_klass_shift();
   uint64_t  pd = (uint64_t)(pointer_delta((void*)v, (void*)base, 1));
-  assert(OopEncodingHeapMax > pd, "change encoding max if new encoding");
+  assert(KlassEncodingMetaspaceMax > pd, "change encoding max if new encoding");
   uint64_t result = pd >> shift;
   assert((result & CONST64(0xffffffff00000000)) == 0, "narrow klass pointer overflow");
   assert(decode_klass(result) == v, "reversibility");

src/share/vm/runtime/arguments.cpp

@@ -1446,13 +1446,18 @@ void Arguments::set_ergonomics_flags() {
     }
     // Set the ClassMetaspaceSize to something that will not need to be
     // expanded, since it cannot be expanded.
-    if (UseCompressedKlassPointers && FLAG_IS_DEFAULT(ClassMetaspaceSize)) {
-      // 100,000 classes seems like a good size, so 100M assumes around 1K
-      // per klass.   The vtable and oopMap is embedded so we don't have a fixed
-      // size per klass.   Eventually, this will be parameterized because it
-      // would also be useful to determine the optimal size of the
-      // systemDictionary.
-      FLAG_SET_ERGO(uintx, ClassMetaspaceSize, 100*M);
+    if (UseCompressedKlassPointers) {
+      if (ClassMetaspaceSize > KlassEncodingMetaspaceMax) {
+        warning("Class metaspace size is too large for UseCompressedKlassPointers");
+        FLAG_SET_DEFAULT(UseCompressedKlassPointers, false);
+      } else if (FLAG_IS_DEFAULT(ClassMetaspaceSize)) {
+        // 100,000 classes seems like a good size, so 100M assumes around 1K
+        // per klass.   The vtable and oopMap is embedded so we don't have a fixed
+        // size per klass.   Eventually, this will be parameterized because it
+        // would also be useful to determine the optimal size of the
+        // systemDictionary.
+        FLAG_SET_ERGO(uintx, ClassMetaspaceSize, 100*M);
+      }
     }
   }
   // Also checks that certain machines are slower with compressed oops

test/runtime/8000968/Test8000968.sh

+#
+#  Copyright (c) 2013, 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.
+#
+
+
+# @test Test8000968.sh
+# @bug 8000968
+# @summary NPG: UseCompressedKlassPointers asserts with ObjectAlignmentInBytes=32
+# @run shell Test8000968.sh
+#
+
+if [ "${TESTJAVA}" = "" ]
+then
+  PARENT=`dirname \`which java\``
+  TESTJAVA=`dirname ${PARENT}`
+  printf "TESTJAVA not set, selecting " ${TESTJAVA}
+  printf "  If this is incorrect, try setting the variable manually.\n"
+fi
+
+
+# set platform-dependent variables
+OS=`uname -s`
+case "$OS" in
+  Windows_* )
+    FS="\\"
+    NULL=NUL
+    ;;
+  * )
+    FS="/"
+    NULL=/dev/null
+    ;;
+esac
+
+JAVA=${TESTJAVA}${FS}bin${FS}java
+
+#
+# See if platform has 64 bit java.
+#
+${JAVA} ${TESTVMOPTS} -d64 -version 2>&1 | grep -i "does not support" > ${NULL}
+if [ "$?" != "1" ]
+then
+  printf "Platform is 32 bit, does not support -XX:ObjectAlignmentInBytes= option.\n"
+  printf "Passed.\n"
+  exit 0
+fi
+
+#
+# Test -XX:ObjectAlignmentInBytes with -XX:+UseCompressedKlassPointers -XX:+UseCompressedOops.
+#
+${JAVA} ${TESTVMOPTS} -d64 -XX:+UseCompressedKlassPointers -XX:+UseCompressedOops -XX:ObjectAlignmentInBytes=16 -version 2>&1 > ${NULL}
+if [ "$?" != "0" ]
+then
+  printf "FAILED: -XX:ObjectAlignmentInBytes=16 option did not work.\n"
+  exit 1
+fi
+
+${JAVA} ${TESTVMOPTS} -d64 -XX:+UseCompressedKlassPointers -XX:+UseCompressedOops -XX:ObjectAlignmentInBytes=32 -version 2>&1 > ${NULL}
+if [ "$?" != "0" ]
+then
+  printf "FAILED: -XX:ObjectAlignmentInBytes=32 option did not work.\n"
+  exit 1
+fi
+
+${JAVA} ${TESTVMOPTS} -d64 -XX:+UseCompressedKlassPointers -XX:+UseCompressedOops -XX:ObjectAlignmentInBytes=64 -version 2>&1 > ${NULL}
+if [ "$?" != "0" ]
+then
+  printf "FAILED: -XX:ObjectAlignmentInBytes=64 option did not work.\n"
+  exit 1
+fi
+
+${JAVA} ${TESTVMOPTS} -d64 -XX:+UseCompressedKlassPointers -XX:+UseCompressedOops -XX:ObjectAlignmentInBytes=128 -version 2>&1 > ${NULL}
+if [ "$?" != "0" ]
+then
+  printf "FAILED: -XX:ObjectAlignmentInBytes=128 option did not work.\n"
+  exit 1
+fi
+
+
+printf "Passed.\n"
+exit 0