1 /*
2  * Summary: Specification of the storage engine interface.
3  *
4  * Copy: See Copyright for the status of this software.
5  *
6  * Author: Trond Norbye <trond.norbye@sun.com>
7  */
8 #ifndef MEMCACHED_DEFAULT_ENGINE_H
9 #define MEMCACHED_DEFAULT_ENGINE_H
10 
11 #include "config.h"
12 
13 #include <pthread.h>
14 #include <stdbool.h>
15 
16 #include <memcached/engine.h>
17 #include <memcached/util.h>
18 #include <memcached/visibility.h>
19 
20 /* Slab sizing definitions. */
21 #define POWER_SMALLEST 1
22 #define POWER_LARGEST  200
23 #define CHUNK_ALIGN_BYTES 8
24 #define DONT_PREALLOC_SLABS
25 #define MAX_NUMBER_OF_SLAB_CLASSES (POWER_LARGEST + 1)
26 
27 /** How long an object can reasonably be assumed to be locked before
28     harvesting it on a low memory condition. */
29 #define TAIL_REPAIR_TIME (3 * 3600)
30 
31 
32 /* Forward decl */
33 struct default_engine;
34 
35 #include "trace.h"
36 #include "items.h"
37 #include "assoc.h"
38 #include "slabs.h"
39 
40 #ifdef __cplusplus
41 extern "C" {
42 #endif
43 
44    /* Flags */
45 #define ITEM_WITH_CAS 1
46 
47 #define ITEM_LINKED (1<<8)
48 
49 /* temp */
50 #define ITEM_SLABBED (2<<8)
51 
52 struct config {
53    bool use_cas;
54    size_t verbose;
55    rel_time_t oldest_live;
56    bool evict_to_free;
57    size_t maxbytes;
58    bool preallocate;
59    float factor;
60    size_t chunk_size;
61    size_t item_size_max;
62    bool ignore_vbucket;
63    bool vb0;
64 };
65 
66 MEMCACHED_PUBLIC_API
67 ENGINE_ERROR_CODE create_instance(uint64_t interface,
68                                   GET_SERVER_API get_server_api,
69                                   ENGINE_HANDLE **handle);
70 
71 /**
72  * Statistic information collected by the default engine
73  */
74 struct engine_stats {
75    pthread_mutex_t lock;
76    uint64_t evictions;
77    uint64_t reclaimed;
78    uint64_t curr_bytes;
79    uint64_t curr_items;
80    uint64_t total_items;
81 };
82 
83 struct engine_scrubber {
84    pthread_mutex_t lock;
85    bool running;
86    uint64_t visited;
87    uint64_t cleaned;
88    time_t started;
89    time_t stopped;
90 };
91 
92 struct tap_connections {
93     pthread_mutex_t lock;
94     size_t size;
95     const void* *clients;
96 };
97 
98 struct vbucket_info {
99     int state : 2;
100 };
101 
102 #define NUM_VBUCKETS 65536
103 
104 /**
105  * Definition of the private instance data used by the default engine.
106  *
107  * This is currently "work in progress" so it is not as clean as it should be.
108  */
109 struct default_engine {
110    ENGINE_HANDLE_V1 engine;
111    SERVER_HANDLE_V1 server;
112    GET_SERVER_API get_server_api;
113 
114    /**
115     * Is the engine initalized or not
116     */
117    bool initialized;
118 
119    struct assoc assoc;
120    struct slabs slabs;
121    struct items items;
122 
123    /**
124     * The cache layer (item_* and assoc_*) is currently protected by
125     * this single mutex
126     */
127    pthread_mutex_t cache_lock;
128 
129    struct config config;
130    struct engine_stats stats;
131    struct engine_scrubber scrubber;
132    struct tap_connections tap_connections;
133 
134    union {
135        engine_info engine_info;
136        char buffer[sizeof(engine_info) +
137                    (sizeof(feature_info) * LAST_REGISTERED_ENGINE_FEATURE)];
138    } info;
139 
140    char vbucket_infos[NUM_VBUCKETS];
141 };
142 
143 char* item_get_data(const hash_item* item);
144 const void* item_get_key(const hash_item* item);
145 void item_set_cas(ENGINE_HANDLE *handle, const void *cookie,
146                   item* item, uint64_t val);
147 uint64_t item_get_cas(const hash_item* item);
148 uint8_t item_get_clsid(const hash_item* item);
149 #endif
150