xref: /freebsd/usr.sbin/nscd/cacheplcs.h (revision 42249ef2)
1 /*-
2  * Copyright (c) 2005 Michael Bushkov <bushman@rsu.ru>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  * $FreeBSD$
27  */
28 
29 #ifndef __NSCD_CACHEPLCS_H__
30 #define __NSCD_CACHEPLCS_H__
31 
32 #include <sys/queue.h>
33 
34 /* common policy definitions */
35 #define CACHELIB_MAX_FREQUENCY 100
36 
37 /*
38  * cache_policy_item_ represents some abstract cache element in the policy
39  * queue. connected_item pointers to the corresponding cache_policy_item_ in
40  * another policy queue.
41  */
42 struct cache_policy_item_ {
43 	char	*key;
44     	size_t	key_size;
45 
46 	size_t	request_count;
47 	struct timeval last_request_time;
48 	struct timeval creation_time;
49 
50 	struct cache_policy_item_ *connected_item;
51 };
52 
53 /*
54  * cache_policy_ represents an abstract policy queue. It can be customized by
55  * setting appropriate function pointers
56  */
57 struct cache_policy_ {
58 	struct cache_policy_item_* (*create_item_func)(void);
59 	void (*destroy_item_func)(struct cache_policy_item_ *);
60 
61 	void (*add_item_func)(struct cache_policy_ *,
62 		struct cache_policy_item_ *);
63 	void (*remove_item_func)(struct cache_policy_ *,
64 		struct cache_policy_item_ *);
65 	void (*update_item_func)(struct cache_policy_ *,
66 		struct cache_policy_item_ *);
67 
68 	struct cache_policy_item_ *(*get_first_item_func)(
69 		struct cache_policy_ *);
70 	struct cache_policy_item_ *(*get_last_item_func)(
71 		struct cache_policy_ *);
72 	struct cache_policy_item_ *(*get_next_item_func)(
73 		struct cache_policy_ *, struct cache_policy_item_ *);
74 	struct cache_policy_item_ *(*get_prev_item_func)(
75 		struct cache_policy_ *, struct cache_policy_item_ *);
76 };
77 
78 /*
79  * LFU cache policy item "inherited" from cache_policy_item_ structure
80  */
81 struct cache_lfu_policy_item_ {
82 	struct cache_policy_item_ parent_data;
83 	int	frequency;
84 
85 	TAILQ_ENTRY(cache_lfu_policy_item_) entries;
86 };
87 
88 TAILQ_HEAD(cache_lfu_policy_group_, cache_lfu_policy_item_);
89 
90 /*
91  * LFU policy queue "inherited" from cache_policy_.
92  */
93 struct cache_lfu_policy_ {
94 	struct cache_policy_ parent_data;
95 	struct cache_lfu_policy_group_ groups[CACHELIB_MAX_FREQUENCY];
96 };
97 
98 /*
99  * LRU and FIFO policies item "inherited" from cache_policy_item_
100  */
101 struct cache_queue_policy_item_ {
102 	struct cache_policy_item_ parent_data;
103 	TAILQ_ENTRY(cache_queue_policy_item_) entries;
104 };
105 
106 /*
107  * LRU and FIFO policies "inherited" from cache_policy_
108  */
109 struct cache_queue_policy_ {
110 	struct cache_policy_ parent_data;
111 	TAILQ_HEAD(cache_queue_policy_head_, cache_queue_policy_item_) head;
112 };
113 
114 typedef struct cache_queue_policy_ cache_fifo_policy_;
115 typedef struct cache_queue_policy_ cache_lru_policy_;
116 
117 /* fifo policy routines */
118 struct cache_policy_ *init_cache_fifo_policy(void);
119 void destroy_cache_fifo_policy(struct cache_policy_ *);
120 
121 /* lru policy routines */
122 struct cache_policy_ *init_cache_lru_policy(void);
123 void destroy_cache_lru_policy(struct cache_policy_ *);
124 
125 /* lfu policy routines */
126 struct cache_policy_ *init_cache_lfu_policy(void);
127 void destroy_cache_lfu_policy(struct cache_policy_ *);
128 
129 #endif
130