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