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33 * @(#)mpool.h 8.2 (Berkeley) 7/14/94
39 #include <sys/queue.h>
41 #include <circ-queue.h>
45 * The memory pool scheme is a simple one. Each in-memory page is referenced
46 * by a bucket which is threaded in up to two of three ways. All active pages
47 * are threaded on a hash chain (hashed by page number) and an lru chain.
48 * Inactive pages are threaded on a free chain. Each reference to a memory
49 * pool is handed an opaque MPOOL cookie which stores all of this information.
52 #define HASHKEY(pgno) ((pgno - 1) % HASHSIZE)
54 /* The BKT structures are the elements of the queues. */
56 CIRCLEQ_ENTRY(_bkt) hq; /* hash queue */
57 CIRCLEQ_ENTRY(_bkt) q; /* lru queue */
58 void *page; /* page */
59 pgno_t pgno; /* page number */
61 #define MPOOL_DIRTY 0x01 /* page needs to be written */
62 #define MPOOL_PINNED 0x02 /* page is pinned into memory */
63 u_int8_t flags; /* flags */
66 typedef struct MPOOL {
67 CIRCLEQ_HEAD(_lqh, _bkt) lqh; /* lru queue head */
68 /* hash queue array */
69 CIRCLEQ_HEAD(_hqh, _bkt) hqh[HASHSIZE];
70 pgno_t curcache; /* current number of cached pages */
71 pgno_t maxcache; /* max number of cached pages */
72 pgno_t npages; /* number of pages in the file */
73 u_long pagesize; /* file page size */
74 int fd; /* file descriptor */
75 /* page in conversion routine */
76 void (*pgin) __P((void *, pgno_t, void *));
77 /* page out conversion routine */
78 void (*pgout) __P((void *, pgno_t, void *));
79 void *pgcookie; /* cookie for page in/out routines */
94 MPOOL *__mpool_open __P((void *, int, pgno_t, pgno_t));
95 MPOOL *mpool_open __P((void *, int, pgno_t, pgno_t));
96 void __mpool_filter __P((MPOOL *, void (*)(void *, pgno_t, void *),
97 void (*)(void *, pgno_t, void *), void *));
98 void mpool_filter __P((MPOOL *, void (*)(void *, pgno_t, void *),
99 void (*)(void *, pgno_t, void *), void *));
100 void *__mpool_new __P((MPOOL *, pgno_t *));
101 void *mpool_new __P((MPOOL *, pgno_t *));
102 void *__mpool_get __P((MPOOL *, pgno_t, u_int));
103 void *mpool_get __P((MPOOL *, pgno_t, u_int));
104 int __mpool_put __P((MPOOL *, void *, u_int));
105 int mpool_put __P((MPOOL *, void *, u_int));
106 int __mpool_sync __P((MPOOL *));
107 int mpool_sync __P((MPOOL *));
108 int __mpool_close __P((MPOOL *));
109 int mpool_close __P((MPOOL *));
111 void mpool_stat __P((MPOOL *));