* Copyright (c) 1991 The Regents of the University of California.
* %sccs.include.redist.c%
* @(#)mpool.h 5.1 (Berkeley) %G%
* The memory pool scheme is a simple one. Each in memory page is referenced
* by a bucket which is threaded in three ways. All active pages are threaded
* on a hash chain (hashed by the page number) and an lru chain. Inactive
* pages are threaded on a free chain. Each reference to a memory pool is
* handed an MPOOL which is the opaque cookie passed to all of the memory
#define HASHKEY(pgno) ((pgno - 1) % HASHSIZE)
/* The BKT structures are the elements of the lists. */
struct BKT
*hnext
; /* next hash bucket */
struct BKT
*hprev
; /* previous hash bucket */
struct BKT
*cnext
; /* next free/lru bucket */
struct BKT
*cprev
; /* previous free/lru bucket */
pgno_t pgno
; /* page number */
#define MPOOL_DIRTY 0x01 /* page needs to be written */
#define MPOOL_PINNED 0x02 /* page is pinned into memory */
unsigned long flags
; /* flags */
/* The BKTHDR structures are the heads of the lists. */
struct BKT
*hnext
; /* next hash bucket */
struct BKT
*hprev
; /* previous hash bucket */
struct BKT
*cnext
; /* next free/lru bucket */
struct BKT
*cprev
; /* previous free/lru bucket */
BKTHDR free
; /* The free list. */
BKTHDR lru
; /* The LRU list. */
BKTHDR hashtable
[HASHSIZE
]; /* Hashed list by page number. */
pgno_t curcache
; /* Current number of cached pages. */
pgno_t maxcache
; /* Max number of cached pages. */
pgno_t npages
; /* Number of pages in the file. */
index_t pagesize
; /* File page size. */
int fd
; /* File descriptor. */
/* Page in conversion routine. */
void (*pgin
) __P((void *, pgno_t
, void *));
/* Page out conversion routine. */
void (*pgout
) __P((void *, pgno_t
, void *));
void *pgcookie
; /* Cookie for page in/out routines. */
#ifdef __MPOOLINTERFACE_PRIVATE
/* Macros to insert/delete into/from hash chain. */
(bp)->hprev->hnext = (bp)->hnext; \
(bp)->hnext->hprev = (bp)->hprev; \
#define inshash(bp, pg) { \
hp = &mp->hashtable[HASHKEY(pg)]; \
(bp)->hnext = hp->hnext; \
(bp)->hprev = (struct BKT *)hp; \
hp->hnext->hprev = (bp); \
/* Macros to insert/delete into/from lru and free chains. */
(bp)->cprev->cnext = (bp)->cnext; \
(bp)->cnext->cprev = (bp)->cprev; \
#define inschain(bp, dp) { \
(bp)->cnext = (dp)->cnext; \
(bp)->cprev = (struct BKT *)(dp); \
(dp)->cnext->cprev = (bp); \
MPOOL
*mpool_open
__P((DBT
*, int, pgno_t
, pgno_t
));
void mpool_filter
__P((MPOOL
*, void (*)(void *, pgno_t
, void *),
void (*)(void *, pgno_t
, void *), void *));
void *mpool_new
__P((MPOOL
*, pgno_t
*));
void *mpool_get
__P((MPOOL
*, pgno_t
, u_int
));
int mpool_put
__P((MPOOL
*, void *, u_int
));
int mpool_sync
__P((MPOOL
*));
int mpool_close
__P((MPOOL
*));
void mpool_stat
__P((MPOOL
*));