include/mpool.h

   1 /*      $NetBSD: mpool.h,v 1.13 2008/08/26 21:18:38 joerg Exp $ */
   2
   3 /*-
   4  * Copyright (c) 1991, 1993, 1994
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  *
  31  *      @(#)mpool.h     8.2 (Berkeley) 7/14/94
  32  */
  33
  34 #ifndef _MPOOL_H_
  35 #define _MPOOL_H_
  36
  37 #include <sys/cdefs.h>
  38 #include <sys/queue.h>
  39
  40 /*
  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.
  46  */
  47 #define HASHSIZE        128
  48 #define HASHKEY(pgno)   ((pgno - 1) % HASHSIZE)
  49
  50 /* The BKT structures are the elements of the queues. */
  51 typedef struct _bkt {
  52         CIRCLEQ_ENTRY(_bkt) hq;         /* hash queue */
  53         CIRCLEQ_ENTRY(_bkt) q;          /* lru queue */
  54         void    *page;                  /* page */
  55         pgno_t   pgno;                  /* page number */
  56
  57 #define MPOOL_DIRTY     0x01            /* page needs to be written */
  58 #define MPOOL_PINNED    0x02            /* page is pinned into memory */
  59         uint8_t flags;                  /* flags */
  60 } BKT;
  61
  62 typedef struct MPOOL {
  63         CIRCLEQ_HEAD(_lqh, _bkt) lqh;   /* lru queue head */
  64                                         /* hash queue array */
  65         CIRCLEQ_HEAD(_hqh, _bkt) hqh[HASHSIZE];
  66         pgno_t  curcache;               /* current number of cached pages */
  67         pgno_t  maxcache;               /* max number of cached pages */
  68         pgno_t  npages;                 /* number of pages in the file */
  69         unsigned long   pagesize;               /* file page size */
  70         int     fd;                     /* file descriptor */
  71                                         /* page in conversion routine */
  72         void    (*pgin)(void *, pgno_t, void *);
  73                                         /* page out conversion routine */
  74         void    (*pgout)(void *, pgno_t, void *);
  75         void    *pgcookie;              /* cookie for page in/out routines */
  76 #ifdef STATISTICS
  77         unsigned long   cachehit;
  78         unsigned long   cachemiss;
  79         unsigned long   pagealloc;
  80         unsigned long   pageflush;
  81         unsigned long   pageget;
  82         unsigned long   pagenew;
  83         unsigned long   pageput;
  84         unsigned long   pageread;
  85         unsigned long   pagewrite;
  86 #endif
  87 } MPOOL;
  88
  89 __BEGIN_DECLS
  90 MPOOL   *mpool_open(void *, int, pgno_t, pgno_t);
  91 void     mpool_filter(MPOOL *, void (*)(void *, pgno_t, void *),
  92             void (*)(void *, pgno_t, void *), void *);
  93 void    *mpool_new(MPOOL *, pgno_t *);
  94 void    *mpool_get(MPOOL *, pgno_t, unsigned int);
  95 int      mpool_put(MPOOL *, void *, unsigned int);
  96 int      mpool_sync(MPOOL *);
  97 int      mpool_close(MPOOL *);
  98 #ifdef STATISTICS
  99 void     mpool_stat(MPOOL *);
 100 #endif
 101 __END_DECLS
 102
 103 #endif /* _MPOOL_H_ */