--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/memory/metachunk.hpp Tue Sep 18 23:35:42 2012 -0700
@@ -0,0 +1,133 @@
+/*
+ * Copyright (c) 2012, 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
+
+// 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 |
+// | | | |
+// | | | | capacity
+// | | | |
+// | | <- top --+ |
+// | | ---+ |
+// | | | used |
+// | | | |
+// | | | |
+// +--------------+ <- bottom ---+ ---+
+
+class Metachunk VALUE_OBJ_CLASS_SPEC {
+ // link to support lists of chunks
+ Metachunk* _next;
+ Metachunk* _prev;
+
+ MetaWord* _bottom;
+ MetaWord* _end;
+ MetaWord* _top;
+ size_t _word_size;
+ // Used in a guarantee() so included in the Product builds
+ // even through it is only for debugging.
+ bool _is_free;
+
+ // 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.
+ static size_t _overhead;
+
+ void set_bottom(MetaWord* v) { _bottom = v; }
+ void set_end(MetaWord* v) { _end = v; }
+ void set_top(MetaWord* v) { _top = v; }
+ void set_word_size(size_t v) { _word_size = v; }
+ public:
+#ifdef ASSERT
+ Metachunk() : _bottom(NULL), _end(NULL), _top(NULL), _is_free(false) {}
+#else
+ Metachunk() : _bottom(NULL), _end(NULL), _top(NULL) {}
+#endif
+
+ // Used to add a Metachunk to a list of Metachunks
+ void set_next(Metachunk* v) { _next = v; assert(v != this, "Boom");}
+ void set_prev(Metachunk* v) { _prev = v; assert(v != this, "Boom");}
+
+ MetaWord* allocate(size_t word_size);
+ static Metachunk* initialize(MetaWord* ptr, size_t word_size);
+
+ // Accessors
+ Metachunk* next() const { return _next; }
+ Metachunk* prev() const { return _prev; }
+ MetaWord* bottom() const { return _bottom; }
+ MetaWord* end() const { return _end; }
+ MetaWord* top() const { return _top; }
+ size_t word_size() const { return _word_size; }
+ size_t size() const volatile { return _word_size; }
+ void set_size(size_t v) { _word_size = v; }
+ bool is_free() { return _is_free; }
+ void set_is_free(bool v) { _is_free = v; }
+ static size_t overhead() { return _overhead; }
+ void clear_next() { set_next(NULL); }
+ void link_prev(Metachunk* ptr) { set_prev(ptr); }
+ uintptr_t* end() { return ((uintptr_t*) this) + size(); }
+ bool cantCoalesce() const { return false; }
+ void link_next(Metachunk* ptr) { set_next(ptr); }
+ void link_after(Metachunk* ptr){
+ link_next(ptr);
+ if (ptr != NULL) ptr->link_prev(this);
+ }
+
+ // Reset top to bottom so chunk can be reused.
+ void reset_empty() { _top = (_bottom + _overhead); }
+ bool is_empty() { return _top == (_bottom + _overhead); }
+
+ // used (has been allocated)
+ // free (available for future allocations)
+ // capacity (total size of chunk)
+ size_t used_word_size();
+ size_t free_word_size();
+ size_t capacity_word_size();
+
+ // 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(Metachunk* tc) const { return true; }
+ bool verify_par_locked() { return true; }
+
+ void assert_is_mangled() const {/* Don't check "\*/}
+
+#ifdef ASSERT
+ void mangle();
+#endif // ASSERT
+
+ void print_on(outputStream* st) const;
+ void verify();
+};
+#endif // SHARE_VM_MEMORY_METACHUNK_HPP