| /* |
| * 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 |