Add linux-next specific files for 20110831
[linux-2.6/next.git] / drivers / staging / zcache / tmem.h
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1 /*
2 * tmem.h
4 * Transcendent memory
6 * Copyright (c) 2009-2011, Dan Magenheimer, Oracle Corp.
7 */
9 #ifndef _TMEM_H_
10 #define _TMEM_H_
12 #include <linux/types.h>
13 #include <linux/highmem.h>
14 #include <linux/hash.h>
15 #include <linux/atomic.h>
18 * These are pre-defined by the Xen<->Linux ABI
20 #define TMEM_PUT_PAGE 4
21 #define TMEM_GET_PAGE 5
22 #define TMEM_FLUSH_PAGE 6
23 #define TMEM_FLUSH_OBJECT 7
24 #define TMEM_POOL_PERSIST 1
25 #define TMEM_POOL_SHARED 2
26 #define TMEM_POOL_PRECOMPRESSED 4
27 #define TMEM_POOL_PAGESIZE_SHIFT 4
28 #define TMEM_POOL_PAGESIZE_MASK 0xf
29 #define TMEM_POOL_RESERVED_BITS 0x00ffff00
32 * sentinels have proven very useful for debugging but can be removed
33 * or disabled before final merge.
35 #define SENTINELS
36 #ifdef SENTINELS
37 #define DECL_SENTINEL uint32_t sentinel;
38 #define SET_SENTINEL(_x, _y) (_x->sentinel = _y##_SENTINEL)
39 #define INVERT_SENTINEL(_x, _y) (_x->sentinel = ~_y##_SENTINEL)
40 #define ASSERT_SENTINEL(_x, _y) WARN_ON(_x->sentinel != _y##_SENTINEL)
41 #define ASSERT_INVERTED_SENTINEL(_x, _y) WARN_ON(_x->sentinel != ~_y##_SENTINEL)
42 #else
43 #define DECL_SENTINEL
44 #define SET_SENTINEL(_x, _y) do { } while (0)
45 #define INVERT_SENTINEL(_x, _y) do { } while (0)
46 #define ASSERT_SENTINEL(_x, _y) do { } while (0)
47 #define ASSERT_INVERTED_SENTINEL(_x, _y) do { } while (0)
48 #endif
50 #define ASSERT_SPINLOCK(_l) WARN_ON(!spin_is_locked(_l))
53 * A pool is the highest-level data structure managed by tmem and
54 * usually corresponds to a large independent set of pages such as
55 * a filesystem. Each pool has an id, and certain attributes and counters.
56 * It also contains a set of hash buckets, each of which contains an rbtree
57 * of objects and a lock to manage concurrency within the pool.
60 #define TMEM_HASH_BUCKET_BITS 8
61 #define TMEM_HASH_BUCKETS (1<<TMEM_HASH_BUCKET_BITS)
63 struct tmem_hashbucket {
64 struct rb_root obj_rb_root;
65 spinlock_t lock;
68 struct tmem_pool {
69 void *client; /* "up" for some clients, avoids table lookup */
70 struct list_head pool_list;
71 uint32_t pool_id;
72 bool persistent;
73 bool shared;
74 atomic_t obj_count;
75 atomic_t refcount;
76 struct tmem_hashbucket hashbucket[TMEM_HASH_BUCKETS];
77 DECL_SENTINEL
80 #define is_persistent(_p) (_p->persistent)
81 #define is_ephemeral(_p) (!(_p->persistent))
84 * An object id ("oid") is large: 192-bits (to ensure, for example, files
85 * in a modern filesystem can be uniquely identified).
88 struct tmem_oid {
89 uint64_t oid[3];
92 static inline void tmem_oid_set_invalid(struct tmem_oid *oidp)
94 oidp->oid[0] = oidp->oid[1] = oidp->oid[2] = -1UL;
97 static inline bool tmem_oid_valid(struct tmem_oid *oidp)
99 return oidp->oid[0] != -1UL || oidp->oid[1] != -1UL ||
100 oidp->oid[2] != -1UL;
103 static inline int tmem_oid_compare(struct tmem_oid *left,
104 struct tmem_oid *right)
106 int ret;
108 if (left->oid[2] == right->oid[2]) {
109 if (left->oid[1] == right->oid[1]) {
110 if (left->oid[0] == right->oid[0])
111 ret = 0;
112 else if (left->oid[0] < right->oid[0])
113 ret = -1;
114 else
115 return 1;
116 } else if (left->oid[1] < right->oid[1])
117 ret = -1;
118 else
119 ret = 1;
120 } else if (left->oid[2] < right->oid[2])
121 ret = -1;
122 else
123 ret = 1;
124 return ret;
127 static inline unsigned tmem_oid_hash(struct tmem_oid *oidp)
129 return hash_long(oidp->oid[0] ^ oidp->oid[1] ^ oidp->oid[2],
130 TMEM_HASH_BUCKET_BITS);
134 * A tmem_obj contains an identifier (oid), pointers to the parent
135 * pool and the rb_tree to which it belongs, counters, and an ordered
136 * set of pampds, structured in a radix-tree-like tree. The intermediate
137 * nodes of the tree are called tmem_objnodes.
140 struct tmem_objnode;
142 struct tmem_obj {
143 struct tmem_oid oid;
144 struct tmem_pool *pool;
145 struct rb_node rb_tree_node;
146 struct tmem_objnode *objnode_tree_root;
147 unsigned int objnode_tree_height;
148 unsigned long objnode_count;
149 long pampd_count;
150 void *extra; /* for private use by pampd implementation */
151 DECL_SENTINEL
154 #define OBJNODE_TREE_MAP_SHIFT 6
155 #define OBJNODE_TREE_MAP_SIZE (1UL << OBJNODE_TREE_MAP_SHIFT)
156 #define OBJNODE_TREE_MAP_MASK (OBJNODE_TREE_MAP_SIZE-1)
157 #define OBJNODE_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long))
158 #define OBJNODE_TREE_MAX_PATH \
159 (OBJNODE_TREE_INDEX_BITS/OBJNODE_TREE_MAP_SHIFT + 2)
161 struct tmem_objnode {
162 struct tmem_obj *obj;
163 DECL_SENTINEL
164 void *slots[OBJNODE_TREE_MAP_SIZE];
165 unsigned int slots_in_use;
168 /* pampd abstract datatype methods provided by the PAM implementation */
169 struct tmem_pamops {
170 void *(*create)(char *, size_t, bool, int,
171 struct tmem_pool *, struct tmem_oid *, uint32_t);
172 int (*get_data)(char *, size_t *, bool, void *, struct tmem_pool *,
173 struct tmem_oid *, uint32_t);
174 int (*get_data_and_free)(char *, size_t *, bool, void *,
175 struct tmem_pool *, struct tmem_oid *,
176 uint32_t);
177 void (*free)(void *, struct tmem_pool *, struct tmem_oid *, uint32_t);
178 void (*free_obj)(struct tmem_pool *, struct tmem_obj *);
179 bool (*is_remote)(void *);
180 void (*new_obj)(struct tmem_obj *);
181 int (*replace_in_obj)(void *, struct tmem_obj *);
183 extern void tmem_register_pamops(struct tmem_pamops *m);
185 /* memory allocation methods provided by the host implementation */
186 struct tmem_hostops {
187 struct tmem_obj *(*obj_alloc)(struct tmem_pool *);
188 void (*obj_free)(struct tmem_obj *, struct tmem_pool *);
189 struct tmem_objnode *(*objnode_alloc)(struct tmem_pool *);
190 void (*objnode_free)(struct tmem_objnode *, struct tmem_pool *);
192 extern void tmem_register_hostops(struct tmem_hostops *m);
194 /* core tmem accessor functions */
195 extern int tmem_put(struct tmem_pool *, struct tmem_oid *, uint32_t index,
196 char *, size_t, bool, bool);
197 extern int tmem_get(struct tmem_pool *, struct tmem_oid *, uint32_t index,
198 char *, size_t *, bool, int);
199 extern int tmem_replace(struct tmem_pool *, struct tmem_oid *, uint32_t index,
200 void *);
201 extern int tmem_flush_page(struct tmem_pool *, struct tmem_oid *,
202 uint32_t index);
203 extern int tmem_flush_object(struct tmem_pool *, struct tmem_oid *);
204 extern int tmem_destroy_pool(struct tmem_pool *);
205 extern void tmem_new_pool(struct tmem_pool *, uint32_t);
206 #endif /* _TMEM_H */