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