cacheplcs.h revision 171795 
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 171795 2007-08-09 13:06:12Z bushman $
27 */
28
29#ifndef __NSCD_CACHEPLCS_H__
30#define __NSCD_CACHEPLCS_H__
31
32#include <sys/queue.h>
33#include <sys/time.h>
34#include <stdlib.h>
35
36/* common policy definitions */
37#define CACHELIB_MAX_FREQUENCY 100
38
39/*
40 * cache_policy_item_ represents some abstract cache element in the policy
41 * queue. connected_item pointers to the corresponding cache_policy_item_ in
42 * another policy queue.
43 */
44struct cache_policy_item_
45{
46	char	*key;
47    	size_t	key_size;
48
49	size_t	request_count;
50	struct timeval last_request_time;
51	struct timeval creation_time;
52
53	struct cache_policy_item_ *connected_item;
54};
55
56/*
57 * cache_policy_ represents an abstract policy queue. It can be customized by
58 * setting appropriate function pointers
59 */
60struct cache_policy_
61{
62	struct cache_policy_item_* (*create_item_func)();
63	void (*destroy_item_func)(struct cache_policy_item_ *);
64
65	void (*add_item_func)(struct cache_policy_ *,
66		struct cache_policy_item_ *);
67	void (*remove_item_func)(struct cache_policy_ *,
68		struct cache_policy_item_ *);
69	void (*update_item_func)(struct cache_policy_ *,
70		struct cache_policy_item_ *);
71
72	struct cache_policy_item_ *(*get_first_item_func)(
73		struct cache_policy_ *);
74	struct cache_policy_item_ *(*get_last_item_func)(
75		struct cache_policy_ *);
76	struct cache_policy_item_ *(*get_next_item_func)(
77		struct cache_policy_ *, struct cache_policy_item_ *);
78	struct cache_policy_item_ *(*get_prev_item_func)(
79		struct cache_policy_ *, struct cache_policy_item_ *);
80};
81
82/*
83 * LFU cache policy item "inherited" from cache_policy_item_ structure
84 */
85struct cache_lfu_policy_item_
86{
87	struct cache_policy_item_ parent_data;
88	int	frequency;
89
90	TAILQ_ENTRY(cache_lfu_policy_item_) entries;
91};
92
93TAILQ_HEAD(cache_lfu_policy_group_, cache_lfu_policy_item_);
94
95/*
96 * LFU policy queue "inherited" from cache_policy_.
97 */
98struct cache_lfu_policy_
99{
100	struct cache_policy_ parent_data;
101	struct cache_lfu_policy_group_ groups[CACHELIB_MAX_FREQUENCY];
102};
103
104/*
105 * LRU and FIFO policies item "inherited" from cache_policy_item_
106 */
107struct cache_queue_policy_item_
108{
109	struct cache_policy_item_ parent_data;
110	TAILQ_ENTRY(cache_queue_policy_item_) entries;
111};
112
113/*
114 * LRU and FIFO policies "inherited" from cache_policy_
115 */
116struct cache_queue_policy_
117{
118	struct cache_policy_ parent_data;
119	TAILQ_HEAD(cache_queue_policy_head_, cache_queue_policy_item_) head;
120};
121
122typedef struct cache_queue_policy_ cache_fifo_policy_;
123typedef struct cache_queue_policy_ cache_lru_policy_;
124
125/* fifo policy routines */
126extern struct cache_policy_ *init_cache_fifo_policy();
127extern void destroy_cache_fifo_policy(struct cache_policy_ *);
128
129/* lru policy routines */
130extern struct cache_policy_ *init_cache_lru_policy();
131extern void destroy_cache_lru_policy(struct cache_policy_ *);
132
133/* lfu policy routines */
134extern struct cache_policy_ *init_cache_lfu_policy();
135extern void destroy_cache_lfu_policy(struct cache_policy_ *);
136
137#endif
138