1 /*- 2 * Copyright (c) 1991 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 * 7 * @(#)mpool.h 5.1 (Berkeley) 09/04/91 8 */ 9 10 /* 11 * The memory pool scheme is a simple one. Each in memory page is referenced 12 * by a bucket which is threaded in three ways. All active pages are threaded 13 * on a hash chain (hashed by the page number) and an lru chain. Inactive 14 * pages are threaded on a free chain. Each reference to a memory pool is 15 * handed an MPOOL which is the opaque cookie passed to all of the memory 16 * routines. 17 */ 18 #define HASHSIZE 128 19 #define HASHKEY(pgno) ((pgno - 1) % HASHSIZE) 20 21 /* The BKT structures are the elements of the lists. */ 22 typedef struct BKT { 23 struct BKT *hnext; /* next hash bucket */ 24 struct BKT *hprev; /* previous hash bucket */ 25 struct BKT *cnext; /* next free/lru bucket */ 26 struct BKT *cprev; /* previous free/lru bucket */ 27 void *page; /* page */ 28 pgno_t pgno; /* page number */ 29 30 #define MPOOL_DIRTY 0x01 /* page needs to be written */ 31 #define MPOOL_PINNED 0x02 /* page is pinned into memory */ 32 unsigned long flags; /* flags */ 33 } BKT; 34 35 /* The BKTHDR structures are the heads of the lists. */ 36 typedef struct BKTHDR { 37 struct BKT *hnext; /* next hash bucket */ 38 struct BKT *hprev; /* previous hash bucket */ 39 struct BKT *cnext; /* next free/lru bucket */ 40 struct BKT *cprev; /* previous free/lru bucket */ 41 } BKTHDR; 42 43 typedef struct MPOOL { 44 BKTHDR free; /* The free list. */ 45 BKTHDR lru; /* The LRU list. */ 46 BKTHDR hashtable[HASHSIZE]; /* Hashed list by page number. */ 47 pgno_t curcache; /* Current number of cached pages. */ 48 pgno_t maxcache; /* Max number of cached pages. */ 49 pgno_t npages; /* Number of pages in the file. */ 50 index_t pagesize; /* File page size. */ 51 int fd; /* File descriptor. */ 52 /* Page in conversion routine. */ 53 void (*pgin) __P((void *, pgno_t, void *)); 54 /* Page out conversion routine. */ 55 void (*pgout) __P((void *, pgno_t, void *)); 56 void *pgcookie; /* Cookie for page in/out routines. */ 57 #ifdef STATISTICS 58 unsigned long cachehit; 59 unsigned long cachemiss; 60 unsigned long pagealloc; 61 unsigned long pageflush; 62 unsigned long pageget; 63 unsigned long pagenew; 64 unsigned long pageput; 65 unsigned long pageread; 66 unsigned long pagewrite; 67 #endif 68 } MPOOL; 69 70 #ifdef __MPOOLINTERFACE_PRIVATE 71 /* Macros to insert/delete into/from hash chain. */ 72 #define rmhash(bp) { \ 73 (bp)->hprev->hnext = (bp)->hnext; \ 74 (bp)->hnext->hprev = (bp)->hprev; \ 75 } 76 #define inshash(bp, pg) { \ 77 hp = &mp->hashtable[HASHKEY(pg)]; \ 78 (bp)->hnext = hp->hnext; \ 79 (bp)->hprev = (struct BKT *)hp; \ 80 hp->hnext->hprev = (bp); \ 81 hp->hnext = (bp); \ 82 } 83 84 /* Macros to insert/delete into/from lru and free chains. */ 85 #define rmchain(bp) { \ 86 (bp)->cprev->cnext = (bp)->cnext; \ 87 (bp)->cnext->cprev = (bp)->cprev; \ 88 } 89 #define inschain(bp, dp) { \ 90 (bp)->cnext = (dp)->cnext; \ 91 (bp)->cprev = (struct BKT *)(dp); \ 92 (dp)->cnext->cprev = (bp); \ 93 (dp)->cnext = (bp); \ 94 } 95 #endif 96 97 __BEGIN_DECLS 98 MPOOL *mpool_open __P((DBT *, int, pgno_t, pgno_t)); 99 void mpool_filter __P((MPOOL *, void (*)(void *, pgno_t, void *), 100 void (*)(void *, pgno_t, void *), void *)); 101 void *mpool_new __P((MPOOL *, pgno_t *)); 102 void *mpool_get __P((MPOOL *, pgno_t, u_int)); 103 int mpool_put __P((MPOOL *, void *, u_int)); 104 int mpool_sync __P((MPOOL *)); 105 int mpool_close __P((MPOOL *)); 106 #ifdef STATISTICS 107 void mpool_stat __P((MPOOL *)); 108 #endif 109 __END_DECLS 110