cacheplcs.h revision 194089 
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: head/usr.sbin/nscd/cacheplcs.h 194089 2009-06-13 00:06:52Z des $
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 */
42struct cache_policy_item_
43{
44	char	*key;
45    	size_t	key_size;
46
47	size_t	request_count;
48	struct timeval last_request_time;
49	struct timeval creation_time;
50
51	struct cache_policy_item_ *connected_item;
52};
53
54/*
55 * cache_policy_ represents an abstract policy queue. It can be customized by
56 * setting appropriate function pointers
57 */
58struct cache_policy_
59{
60	struct cache_policy_item_* (*create_item_func)(void);
61	void (*destroy_item_func)(struct cache_policy_item_ *);
62
63	void (*add_item_func)(struct cache_policy_ *,
64		struct cache_policy_item_ *);
65	void (*remove_item_func)(struct cache_policy_ *,
66		struct cache_policy_item_ *);
67	void (*update_item_func)(struct cache_policy_ *,
68		struct cache_policy_item_ *);
69
70	struct cache_policy_item_ *(*get_first_item_func)(
71		struct cache_policy_ *);
72	struct cache_policy_item_ *(*get_last_item_func)(
73		struct cache_policy_ *);
74	struct cache_policy_item_ *(*get_next_item_func)(
75		struct cache_policy_ *, struct cache_policy_item_ *);
76	struct cache_policy_item_ *(*get_prev_item_func)(
77		struct cache_policy_ *, struct cache_policy_item_ *);
78};
79
80/*
81 * LFU cache policy item "inherited" from cache_policy_item_ structure
82 */
83struct cache_lfu_policy_item_
84{
85	struct cache_policy_item_ parent_data;
86	int	frequency;
87
88	TAILQ_ENTRY(cache_lfu_policy_item_) entries;
89};
90
91TAILQ_HEAD(cache_lfu_policy_group_, cache_lfu_policy_item_);
92
93/*
94 * LFU policy queue "inherited" from cache_policy_.
95 */
96struct cache_lfu_policy_
97{
98	struct cache_policy_ parent_data;
99	struct cache_lfu_policy_group_ groups[CACHELIB_MAX_FREQUENCY];
100};
101
102/*
103 * LRU and FIFO policies item "inherited" from cache_policy_item_
104 */
105struct cache_queue_policy_item_
106{
107	struct cache_policy_item_ parent_data;
108	TAILQ_ENTRY(cache_queue_policy_item_) entries;
109};
110
111/*
112 * LRU and FIFO policies "inherited" from cache_policy_
113 */
114struct cache_queue_policy_
115{
116	struct cache_policy_ parent_data;
117	TAILQ_HEAD(cache_queue_policy_head_, cache_queue_policy_item_) head;
118};
119
120typedef struct cache_queue_policy_ cache_fifo_policy_;
121typedef struct cache_queue_policy_ cache_lru_policy_;
122
123/* fifo policy routines */
124extern struct cache_policy_ *init_cache_fifo_policy(void);
125extern void destroy_cache_fifo_policy(struct cache_policy_ *);
126
127/* lru policy routines */
128extern struct cache_policy_ *init_cache_lru_policy(void);
129extern void destroy_cache_lru_policy(struct cache_policy_ *);
130
131/* lfu policy routines */
132extern struct cache_policy_ *init_cache_lfu_policy(void);
133extern void destroy_cache_lfu_policy(struct cache_policy_ *);
134
135#endif
136