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