Fri, 01 Feb 2013 23:48:08 +0100
8005012: Add WB APIs to better support NMT testing
Summary: Add WB API functions to enable better NMT testing
Reviewed-by: dholmes, zgu
1 /*
2 * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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23 */
24 #ifndef SHARE_VM_MEMORY_METACHUNK_HPP
25 #define SHARE_VM_MEMORY_METACHUNK_HPP
27 // Metachunk - Quantum of allocation from a Virtualspace
28 // Metachunks are reused (when freed are put on a global freelist) and
29 // have no permanent association to a SpaceManager.
31 // +--------------+ <- end
32 // | | --+ ---+
33 // | | | free |
34 // | | | |
35 // | | | | capacity
36 // | | | |
37 // | | <- top --+ |
38 // | | ---+ |
39 // | | | used |
40 // | | | |
41 // | | | |
42 // +--------------+ <- bottom ---+ ---+
44 class Metachunk VALUE_OBJ_CLASS_SPEC {
45 // link to support lists of chunks
46 Metachunk* _next;
47 Metachunk* _prev;
49 MetaWord* _bottom;
50 MetaWord* _end;
51 MetaWord* _top;
52 size_t _word_size;
53 // Used in a guarantee() so included in the Product builds
54 // even through it is only for debugging.
55 bool _is_free;
57 // Metachunks are allocated out of a MetadataVirtualSpace and
58 // and use some of its space to describe itself (plus alignment
59 // considerations). Metadata is allocated in the rest of the chunk.
60 // This size is the overhead of maintaining the Metachunk within
61 // the space.
62 static size_t _overhead;
64 void set_bottom(MetaWord* v) { _bottom = v; }
65 void set_end(MetaWord* v) { _end = v; }
66 void set_top(MetaWord* v) { _top = v; }
67 void set_word_size(size_t v) { _word_size = v; }
68 public:
69 #ifdef ASSERT
70 Metachunk() : _bottom(NULL), _end(NULL), _top(NULL), _is_free(false),
71 _next(NULL), _prev(NULL) {}
72 #else
73 Metachunk() : _bottom(NULL), _end(NULL), _top(NULL),
74 _next(NULL), _prev(NULL) {}
75 #endif
77 // Used to add a Metachunk to a list of Metachunks
78 void set_next(Metachunk* v) { _next = v; assert(v != this, "Boom");}
79 void set_prev(Metachunk* v) { _prev = v; assert(v != this, "Boom");}
81 MetaWord* allocate(size_t word_size);
82 static Metachunk* initialize(MetaWord* ptr, size_t word_size);
84 // Accessors
85 Metachunk* next() const { return _next; }
86 Metachunk* prev() const { return _prev; }
87 MetaWord* bottom() const { return _bottom; }
88 MetaWord* end() const { return _end; }
89 MetaWord* top() const { return _top; }
90 size_t word_size() const { return _word_size; }
91 size_t size() const volatile { return _word_size; }
92 void set_size(size_t v) { _word_size = v; }
93 bool is_free() { return _is_free; }
94 void set_is_free(bool v) { _is_free = v; }
95 static size_t overhead() { return _overhead; }
96 void clear_next() { set_next(NULL); }
97 void link_prev(Metachunk* ptr) { set_prev(ptr); }
98 uintptr_t* end() { return ((uintptr_t*) this) + size(); }
99 bool cantCoalesce() const { return false; }
100 void link_next(Metachunk* ptr) { set_next(ptr); }
101 void link_after(Metachunk* ptr){
102 link_next(ptr);
103 if (ptr != NULL) ptr->link_prev(this);
104 }
106 // Reset top to bottom so chunk can be reused.
107 void reset_empty() { _top = (_bottom + _overhead); _next = NULL; _prev = NULL; }
108 bool is_empty() { return _top == (_bottom + _overhead); }
110 // used (has been allocated)
111 // free (available for future allocations)
112 // capacity (total size of chunk)
113 size_t used_word_size() const;
114 size_t free_word_size() const;
115 size_t capacity_word_size()const;
117 // Debug support
118 #ifdef ASSERT
119 void* prev_addr() const { return (void*)&_prev; }
120 void* next_addr() const { return (void*)&_next; }
121 void* size_addr() const { return (void*)&_word_size; }
122 #endif
123 bool verify_chunk_in_free_list(Metachunk* tc) const { return true; }
124 bool verify_par_locked() { return true; }
126 void assert_is_mangled() const {/* Don't check "\*/}
128 NOT_PRODUCT(void mangle();)
130 void print_on(outputStream* st) const;
131 void verify();
132 };
133 #endif // SHARE_VM_MEMORY_METACHUNK_HPP