jdk8-mips64-public/hotspot: comparison src/share/vm/memory/metachunk.hpp

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+/*
+* Copyright (c) 2012, 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.
+*
+*/
+#ifndef SHARE_VM_MEMORY_METACHUNK_HPP
+#define SHARE_VM_MEMORY_METACHUNK_HPP
+#include "memory/allocation.hpp"
+#include "utilities/debug.hpp"
+#include "utilities/globalDefinitions.hpp"
+class VirtualSpaceNode;
+// Super class of Metablock and Metachunk to allow them to
+// be put on the FreeList and in the BinaryTreeDictionary.
+template <class T>
+class Metabase VALUE_OBJ_CLASS_SPEC {
+size_t _word_size;
+T*     _next;
+T*     _prev;
+protected:
+Metabase(size_t word_size) : _word_size(word_size), _next(NULL), _prev(NULL) {}
+public:
+T* next() const         { return _next; }
+T* prev() const         { return _prev; }
+void set_next(T* v)     { _next = v; assert(v != this, "Boom");}
+void set_prev(T* v)     { _prev = v; assert(v != this, "Boom");}
+void clear_next()       { set_next(NULL); }
+void clear_prev()       { set_prev(NULL); }
+size_t size() const volatile { return _word_size; }
+void set_size(size_t v) { _word_size = v; }
+void link_next(T* ptr)  { set_next(ptr); }
+void link_prev(T* ptr)  { set_prev(ptr); }
+void link_after(T* ptr) {
+link_next(ptr);
+if (ptr != NULL) ptr->link_prev((T*)this);
+}
+uintptr_t* end() const        { return ((uintptr_t*) this) + size(); }
+bool cantCoalesce() const     { return false; }
+// Debug support
+#ifdef ASSERT
+void* prev_addr() const { return (void*)&_prev; }
+void* next_addr() const { return (void*)&_next; }
+void* size_addr() const { return (void*)&_word_size; }
+#endif
+bool verify_chunk_in_free_list(T* tc) const { return true; }
+bool verify_par_locked() { return true; }
+void assert_is_mangled() const {/* Don't check "\*/}
+bool is_free()                 { return true; }
+};
+//  Metachunk - Quantum of allocation from a Virtualspace
+//    Metachunks are reused (when freed are put on a global freelist) and
+//    have no permanent association to a SpaceManager.
+//            +--------------+ <- end    --+       --+
+//            |              |             |         |
+//            |              |             | free    |
+//            |              |             |         |
+//            |              |             |         | size | capacity
+//            |              |             |         |
+//            |              | <- top   -- +         |
+//            |              |             |         |
+//            |              |             | used    |
+//            |              |             |         |
+//            |              |             |         |
+//            +--------------+ <- bottom --+       --+
+class Metachunk : public Metabase<Metachunk> {
+friend class TestMetachunk;
+// The VirtualSpaceNode containing this chunk.
+VirtualSpaceNode* _container;
+// Current allocation top.
+MetaWord* _top;
+DEBUG_ONLY(bool _is_tagged_free;)
+MetaWord* initial_top() const { return (MetaWord*)this + overhead(); }
+MetaWord* top() const         { return _top; }
+public:
+// Metachunks are allocated out of a MetadataVirtualSpace and
+// and use some of its space to describe itself (plus alignment
+// considerations).  Metadata is allocated in the rest of the chunk.
+// This size is the overhead of maintaining the Metachunk within
+// the space.
+// Alignment of each allocation in the chunks.
+static size_t object_alignment();
+// Size of the Metachunk header, including alignment.
+static size_t overhead();
+Metachunk(size_t word_size , VirtualSpaceNode* container);
+MetaWord* allocate(size_t word_size);
+VirtualSpaceNode* container() const { return _container; }
+MetaWord* bottom() const { return (MetaWord*) this; }
+// Reset top to bottom so chunk can be reused.
+void reset_empty() { _top = initial_top(); clear_next(); clear_prev(); }
+bool is_empty() { return _top == initial_top(); }
+// used (has been allocated)
+// free (available for future allocations)
+size_t word_size() const { return size(); }
+size_t used_word_size() const;
+size_t free_word_size() const;
+#ifdef ASSERT
+bool is_tagged_free() { return _is_tagged_free; }
+void set_is_tagged_free(bool v) { _is_tagged_free = v; }
+#endif
+bool contains(const void* ptr) { return bottom() <= ptr && ptr < _top; }
+NOT_PRODUCT(void mangle();)
+void print_on(outputStream* st) const;
+void verify();
+};
+// Metablock is the unit of allocation from a Chunk.
+//
+// A Metablock may be reused by its SpaceManager but are never moved between
+// SpaceManagers.  There is no explicit link to the Metachunk
+// from which it was allocated.  Metablock may be deallocated and
+// put on a freelist but the space is never freed, rather
+// the Metachunk it is a part of will be deallocated when it's
+// associated class loader is collected.
+class Metablock : public Metabase<Metablock> {
+friend class VMStructs;
+public:
+Metablock(size_t word_size) : Metabase<Metablock>(word_size) {}
+};
+#endif  // SHARE_VM_MEMORY_METACHUNK_HPP

Mercurial > jdk8-mips64-public > hotspot / file comparison

comparison: src/share/vm/memory/metachunk.hpp

src/share/vm/memory/metachunk.hpp