usr.sbin/nscd/cacheplcs.h

   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: src/usr.sbin/nscd/cacheplcs.h,v 1.3 2007/09/27 12:30:11 bushman Exp $
  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  */
  44 struct 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  */
  60 struct cache_policy_
  61 {
  62         struct cache_policy_item_* (*create_item_func)(void);
  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  */
  85 struct 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
  93 TAILQ_HEAD(cache_lfu_policy_group_, cache_lfu_policy_item_);
  94
  95 /*
  96  * LFU policy queue "inherited" from cache_policy_.
  97  */
  98 struct 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  */
 107 struct 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  */
 116 struct cache_queue_policy_
 117 {
 118         struct cache_policy_ parent_data;
 119         TAILQ_HEAD(cache_queue_policy_head_, cache_queue_policy_item_) head;
 120 };
 121
 122 typedef struct cache_queue_policy_ cache_fifo_policy_;
 123 typedef struct cache_queue_policy_ cache_lru_policy_;
 124
 125 /* fifo policy routines */
 126 extern struct cache_policy_ *init_cache_fifo_policy(void);
 127 extern void destroy_cache_fifo_policy(struct cache_policy_ *);
 128
 129 /* lru policy routines */
 130 extern struct cache_policy_ *init_cache_lru_policy(void);
 131 extern void destroy_cache_lru_policy(struct cache_policy_ *);
 132
 133 /* lfu policy routines */
 134 extern struct cache_policy_ *init_cache_lfu_policy(void);
 135 extern void destroy_cache_lfu_policy(struct cache_policy_ *);
 136
 137 #endif