tools/diag/dumpvfscache/dumpvfscache.c

   1 /* $FreeBSD$ */
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <unistd.h>
   5 #include <fcntl.h>
   6 #include <kvm.h>
   7 #include <nlist.h>
   8 #include <sysexits.h>
   9 #include <sys/uio.h>
  10 #include <sys/namei.h>
  11 #include <sys/param.h>
  12 #include <sys/queue.h>
  13 #include <sys/time.h>
  14 #include <sys/vnode.h>
  15 /*----------------------------------*/
  16 static u_int crc16_table[16] = {
  17     0x0000, 0xCC01, 0xD801, 0x1400,
  18     0xF001, 0x3C00, 0x2800, 0xE401,
  19     0xA001, 0x6C00, 0x7800, 0xB401,
  20     0x5000, 0x9C01, 0x8801, 0x4400
  21 };
  22
  23 /* XXX Taken from sys/kern/vfs_cache.c */
  24 struct  namecache {
  25         LIST_ENTRY(namecache) nc_hash;
  26         LIST_ENTRY(namecache) nc_src;
  27         TAILQ_ENTRY(namecache) nc_dst;
  28         struct  vnode *nc_dvp;
  29         struct  vnode *nc_vp;
  30         u_char  nc_flag;
  31         u_char  nc_nlen;
  32         char    nc_name[0];
  33 };
  34
  35 static u_short
  36 wlpsacrc(u_char *buf, u_int len)
  37 {
  38     u_short     crc = 0;
  39     int         i, r1;
  40
  41     for (i = 0; i < len; i++, buf++) {
  42         /* lower 4 bits */
  43         r1 = crc16_table[crc & 0xF];
  44         crc = (crc >> 4) & 0x0FFF;
  45         crc = crc ^ r1 ^ crc16_table[*buf & 0xF];
  46
  47         /* upper 4 bits */
  48         r1 = crc16_table[crc & 0xF];
  49         crc = (crc >> 4) & 0x0FFF;
  50         crc = crc ^ r1 ^ crc16_table[(*buf >> 4) & 0xF];
  51     }
  52     return(crc);
  53 }
  54
  55 /*----------------------------------*/
  56 struct nlist nl[] = {
  57         { "_nchash", 0},
  58         { "_nchashtbl", 0},
  59         { 0, 0 },
  60 };
  61
  62 int histo[2047];
  63 int histn[2047];
  64 int *newbucket;
  65
  66 int
  67 main(int argc, char **argv)
  68 {
  69         int nchash, i, j, k, kn;
  70         int nb, p1, p2;
  71         u_long p;
  72         LIST_HEAD(nchashhead, namecache) *nchashtbl;
  73         struct namecache *nc;
  74         struct vnode vn;
  75
  76         kvm_t *kvm = kvm_open(NULL, NULL, NULL, O_RDONLY, argv[0]);
  77         if (kvm == NULL)
  78                 return(EX_OSERR);
  79
  80         printf("kvm: %p\n", kvm);
  81         printf("kvm_nlist: %d\n", kvm_nlist(kvm, nl));
  82         kvm_read(kvm, nl[0].n_value, &nchash, sizeof nchash);
  83         nchash++;
  84         nchashtbl = malloc(nchash * sizeof *nchashtbl);
  85         nc = malloc(sizeof *nc + NAME_MAX);
  86         newbucket = malloc(nchash * sizeof (int));
  87         memset(newbucket, 0, nchash * sizeof (int));
  88         kvm_read(kvm, nl[1].n_value, &p, sizeof p);
  89         kvm_read(kvm, p, nchashtbl, nchash * sizeof *nchashtbl);
  90         for (i=0; i < nchash; i++) {
  91 #if 0
  92                 printf("%d\n", i);
  93 #endif
  94                 nb=0;
  95                 p = (u_long)LIST_FIRST(nchashtbl+i);
  96                 while (p) {
  97                         nb++;
  98                         kvm_read(kvm, p, nc, sizeof *nc + NAME_MAX);
  99                         kvm_read(kvm, (u_long)nc->nc_dvp, &vn, sizeof vn);
 100                         nc->nc_name[nc->nc_nlen] = '\0';
 101                         for (j=k=kn=0;nc->nc_name[j];j++) {
 102                                 k+= nc->nc_name[j];
 103                                 kn <<= 1;
 104                                 kn+= nc->nc_name[j];
 105                         }
 106                         /*
 107                         kn = k;
 108                         */
 109                         kn = wlpsacrc(nc->nc_name,nc->nc_nlen);
 110
 111                         /* kn += (u_long)vn.v_data >> 8;  */
 112                         /* kn += (u_long)nc->nc_dvp >> 7;    */
 113                         kn += vn.v_id;
 114                         kn &= (nchash - 1);
 115                         newbucket[kn]++;
 116 #if 1
 117                         printf("%4d  dvp %08x  hash %08x  vp %08x  id %08x  name <%s>\n",
 118                                 i,nc->nc_dvp, k, nc->nc_vp, vn.v_id, nc->nc_name);
 119 #endif
 120                         p = (u_long)LIST_NEXT(nc, nc_hash);
 121                 }
 122                 histo[nb]++;
 123         }
 124         for (i=0; i < nchash; i++) {
 125                 histn[newbucket[i]]++;
 126         }
 127         p1=p2 = 0;
 128         for (i=0;i<30;i++) {
 129                 p1 += histo[i] * i;
 130                 p2 += histn[i] * i;
 131                 if (histo[i] || histn[i])
 132                         printf("H%02d %4d %4d / %4d %4d\n",i,histo[i], p1 , histn[i], p2);
 133         }
 134
 135         return (0);
 136 }
 137