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29 * @(#)mpool.h 8.4 (Berkeley) 11/2/95
36 #include <sys/queue.h>
39 * The memory pool scheme is a simple one. Each in-memory page is referenced
40 * by a bucket which is threaded in up to two of three ways. All active pages
41 * are threaded on a hash chain (hashed by page number) and an lru chain.
42 * Inactive pages are threaded on a free chain. Each reference to a memory
43 * pool is handed an opaque MPOOL cookie which stores all of this information.
46 #define HASHKEY(pgno) ((pgno - 1 + HASHSIZE) % HASHSIZE)
48 /* The BKT structures are the elements of the queues. */
50 TAILQ_ENTRY(_bkt
) hq
; /* hash queue */
51 TAILQ_ENTRY(_bkt
) q
; /* lru queue */
52 void *page
; /* page */
53 pgno_t pgno
; /* page number */
55 #define MPOOL_DIRTY 0x01 /* page needs to be written */
56 #define MPOOL_PINNED 0x02 /* page is pinned into memory */
57 #define MPOOL_INUSE 0x04 /* page address is valid */
58 u_int8_t flags
; /* flags */
61 typedef struct MPOOL
{
62 TAILQ_HEAD(_lqh
, _bkt
) lqh
; /* lru queue head */
63 /* hash queue array */
64 TAILQ_HEAD(_hqh
, _bkt
) hqh
[HASHSIZE
];
65 pgno_t curcache
; /* current number of cached pages */
66 pgno_t maxcache
; /* max number of cached pages */
67 pgno_t npages
; /* number of pages in the file */
68 unsigned long pagesize
; /* file page size */
69 int fd
; /* file descriptor */
70 /* page in conversion routine */
71 void (*pgin
)(void *, pgno_t
, void *);
72 /* page out conversion routine */
73 void (*pgout
)(void *, pgno_t
, void *);
74 void *pgcookie
; /* cookie for page in/out routines */
76 unsigned long cachehit
;
77 unsigned long cachemiss
;
78 unsigned long pagealloc
;
79 unsigned long pageflush
;
80 unsigned long pageget
;
81 unsigned long pagenew
;
82 unsigned long pageput
;
83 unsigned long pageread
;
84 unsigned long pagewrite
;
88 #define MPOOL_IGNOREPIN 0x01 /* Ignore if the page is pinned. */
89 #define MPOOL_PAGE_REQUEST 0x01 /* Allocate a new page with a
90 specific page number. */
91 #define MPOOL_PAGE_NEXT 0x02 /* Allocate a new page with the next
95 MPOOL
*mpool_open(void *, int, pgno_t
, pgno_t
);
96 void mpool_filter(MPOOL
*, void (*)(void *, pgno_t
, void *),
97 void (*)(void *, pgno_t
, void *), void *);
98 void *mpool_new(MPOOL
*, pgno_t
*, unsigned int);
99 void *mpool_get(MPOOL
*, pgno_t
, unsigned int);
100 int mpool_delete(MPOOL
*, void *);
101 int mpool_put(MPOOL
*, void *, unsigned int);
102 int mpool_sync(MPOOL
*);
103 int mpool_close(MPOOL
*);
105 void mpool_stat(MPOOL
*);