include/mpool.h

   1 /*-
   2  * Copyright (c) 1991, 1993, 1994
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  *      @(#)mpool.h     8.4 (Berkeley) 11/2/95
  30  * $FreeBSD: head/include/mpool.h 203964 2010-02-16 19:39:50Z imp $
  31  */
  32
  33 #ifndef _MPOOL_H_
  34 #define _MPOOL_H_
  35
  36 #include <sys/cdefs.h>
  37 #include <sys/queue.h>
  38 #include <db.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) % HASHSIZE)
  49
  50 /* The BKT structures are the elements of the queues. */
  51 typedef struct _bkt {
  52         TAILQ_ENTRY(_bkt) hq;           /* hash queue */
  53         TAILQ_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 #define MPOOL_INUSE     0x04            /* page address is valid */
  60         u_int8_t flags;                 /* flags */
  61 } BKT;
  62
  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 */
  77 #ifdef STATISTICS
  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;
  87 #endif
  88 } MPOOL;
  89
  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
  94                                           page number. */
  95
  96 __BEGIN_DECLS
  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 *);
 106 #ifdef STATISTICS
 107 void     mpool_stat(MPOOL *);
 108 #endif
 109 __END_DECLS
 110
 111 #endif