--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc/shared/spaceDecorator.hpp Wed May 13 15:16:06 2015 +0200
@@ -0,0 +1,150 @@
+/*
+ * Copyright (c) 2002, 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.
+ *
+ * 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.
+ *
+ */
+
+#ifndef SHARE_VM_GC_SHARED_SPACEDECORATOR_HPP
+#define SHARE_VM_GC_SHARED_SPACEDECORATOR_HPP
+
+#include "gc/parallel/mutableSpace.hpp"
+#include "gc/shared/space.hpp"
+#include "utilities/globalDefinitions.hpp"
+
+class SpaceDecorator: public AllStatic {
+ public:
+ // Initialization flags.
+ static const bool Clear = true;
+ static const bool DontClear = false;
+ static const bool Mangle = true;
+ static const bool DontMangle = false;
+};
+
+// Functionality for use with class Space and class MutableSpace.
+// The approach taken with the mangling is to mangle all
+// the space initially and then to mangle areas that have
+// been allocated since the last collection. Mangling is
+// done in the context of a generation and in the context
+// of a space.
+// The space in a generation is mangled when it is first
+// initialized and when the generation grows. The spaces
+// are not necessarily up-to-date when this mangling occurs
+// and the method mangle_region() is used.
+// After allocations have been done in a space, the space generally
+// need to be remangled. Remangling is only done on the
+// recently allocated regions in the space. Typically, that is
+// the region between the new top and the top just before a
+// garbage collection.
+// An exception to the usual mangling in a space is done when the
+// space is used for an extraordinary purpose. Specifically, when
+// to-space is used as scratch space for a mark-sweep-compact
+// collection.
+// Spaces are mangled after a collection. If the generation
+// grows after a collection, the added space is mangled as part of
+// the growth of the generation. No additional mangling is needed when the
+// spaces are resized after an expansion.
+// The class SpaceMangler keeps a pointer to the top of the allocated
+// area and provides the methods for doing the piece meal mangling.
+// Methods for doing sparces and full checking of the mangling are
+// included. The full checking is done if DEBUG_MANGLING is defined.
+// GenSpaceMangler is used with the GenCollectedHeap collectors and
+// MutableSpaceMangler is used with the ParallelScavengeHeap collectors.
+// These subclasses abstract the differences in the types of spaces used
+// by each heap.
+
+class SpaceMangler: public CHeapObj<mtGC> {
+ friend class VMStructs;
+
+ // High water mark for allocations. Typically, the space above
+ // this point have been mangle previously and don't need to be
+ // touched again. Space below this point has been allocated
+ // and remangling is needed between the current top and this
+ // high water mark.
+ HeapWord* _top_for_allocations;
+ HeapWord* top_for_allocations() { return _top_for_allocations; }
+
+ public:
+
+ // Setting _top_for_allocations to NULL at initialization
+ // makes it always below top so that mangling done as part
+ // of the initialize() call of a space does nothing (as it
+ // should since the mangling is done as part of the constructor
+ // for the space.
+ SpaceMangler() : _top_for_allocations(NULL) {}
+
+ // Methods for top and end that delegate to the specific
+ // space type.
+ virtual HeapWord* top() const = 0;
+ virtual HeapWord* end() const = 0;
+
+ // Return true if q matches the mangled pattern.
+ static bool is_mangled(HeapWord* q) PRODUCT_RETURN0;
+
+ // Used to save the an address in a space for later use during mangling.
+ void set_top_for_allocations(HeapWord* v);
+
+ // Overwrites the unused portion of this space.
+ // Mangle only the region not previously mangled [top, top_previously_mangled)
+ void mangle_unused_area();
+ // Mangle all the unused region [top, end)
+ void mangle_unused_area_complete();
+ // Do some sparse checking on the area that should have been mangled.
+ void check_mangled_unused_area(HeapWord* limit) PRODUCT_RETURN;
+ // Do a complete check of the area that should be mangled.
+ void check_mangled_unused_area_complete() PRODUCT_RETURN;
+
+ // Mangle the MemRegion. This is a non-space specific mangler. It
+ // is used during the initial mangling of a space before the space
+ // is fully constructed. Also is used when a generation is expanded
+ // and possibly before the spaces have been reshaped to to the new
+ // size of the generation.
+ static void mangle_region(MemRegion mr) PRODUCT_RETURN;
+};
+
+class ContiguousSpace;
+
+// For use with GenCollectedHeap's
+class GenSpaceMangler: public SpaceMangler {
+ ContiguousSpace* _sp;
+
+ ContiguousSpace* sp() { return _sp; }
+
+ HeapWord* top() const { return _sp->top(); }
+ HeapWord* end() const { return _sp->end(); }
+
+ public:
+ GenSpaceMangler(ContiguousSpace* sp) : SpaceMangler(), _sp(sp) {}
+};
+
+// For use with ParallelScavengeHeap's.
+class MutableSpaceMangler: public SpaceMangler {
+ MutableSpace* _sp;
+
+ MutableSpace* sp() { return _sp; }
+
+ HeapWord* top() const { return _sp->top(); }
+ HeapWord* end() const { return _sp->end(); }
+
+ public:
+ MutableSpaceMangler(MutableSpace* sp) : SpaceMangler(), _sp(sp) {}
+};
+
+#endif // SHARE_VM_GC_SHARED_SPACEDECORATOR_HPP