usr/src/sys/h/cmap.h

/*      cmap.h  4.1     11/9/80 */

/*
 * core map entry
 *
 * NB: THE SIZE OF THIS STRUCTURE IS WELL KNOWN IN cmap.m
 */
struct cmap
{
unsigned int    c_next:13,      /* index of next free list entry */
                c_prev:13,      /* index of previous free list entry */
                c_mdev:4,       /* which mounted dev this is from */
                c_lock:1,       /* locked for raw i/o or pagein */
                c_want:1,       /* wanted */
                c_page:16,      /* virtual page number in segment */
                c_hlink:13,     /* hash link for <blkno,mdev> */
                c_intrans:1,    /* intransit bit */
                c_free:1,       /* on the free list */
                c_gone:1,       /* associated page has been released */
                c_type:2,       /* type CSYS or CTEXT or CSTACK or CDATA */
                c_blkno:20,     /* disk block this is a copy of */
                c_ndx:10;       /* index of owner proc or text */
};

#define CMHEAD  0

/*
 * Shared text pages are not totally abandoned when a process
 * exits, but are remembered while in the free list hashed by <mdev,blkno>
 * off the cmhash structure so that they can be reattached
 * if another instance of the program runs again soon.
 */
#define CMHSIZ  512             /* SHOULD BE DYNAMIC */
#define CMHASH(bn)      ((bn)&(CMHSIZ-1))

#ifdef  KERNEL
extern  struct cmap *cmap;
extern  struct cmap *ecmap;
struct  cmap *mfind();
struct  cmap zcmap;
int     firstfree, maxfree;
int     ecmx;                   /* cmap index of ecmap */
short   cmhash[CMHSIZ];
#endif

/* bits defined in c_type */

#define CSYS            0               /* none of below */
#define CTEXT           1               /* belongs to shared text segment */
#define CDATA           2               /* belongs to data segment */
#define CSTACK          3               /* belongs to stack segment */

#define pgtocm(x)       ((((x)-firstfree) / CLSIZE) + 1)
#define cmtopg(x)       ((((x)-1) * CLSIZE) + firstfree)