lib/libkvm/kvm_getswapinfo.c

   1 /*
   2  * Copyright (c) 1999 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@backplane.com>
   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  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  * $FreeBSD: src/lib/libkvm/kvm_getswapinfo.c,v 1.10.2.4 2003/01/12 09:23:13 dillon Exp $
  35  * $DragonFly: src/lib/libkvm/kvm_getswapinfo.c,v 1.5 2006/03/18 18:15:35 dillon Exp $
  36  */
  37
  38 #define _KERNEL_STRUCTURES
  39
  40 #include <sys/param.h>
  41 #include <sys/time.h>
  42 #include <sys/ucred.h>
  43 #include <sys/stat.h>
  44 #include <sys/conf.h>
  45 #include <sys/blist.h>
  46
  47 #include <err.h>
  48 #include <fcntl.h>
  49 #include <kvm.h>
  50 #include <nlist.h>
  51 #include <paths.h>
  52 #include <stdio.h>
  53 #include <stdlib.h>
  54 #include <string.h>
  55 #include <unistd.h>
  56
  57 static struct nlist kvm_swap_nl[] = {
  58         { "_swapblist" },       /* new radix swap list          */
  59         { "_swdevt" },          /* list of swap devices and sizes */
  60         { "_nswdev" },          /* number of swap devices */
  61         { "_dmmax" },           /* maximum size of a swap block */
  62         { "" }
  63 };
  64
  65 #define NL_SWAPBLIST    0
  66 #define NL_SWDEVT       1
  67 #define NL_NSWDEV       2
  68 #define NL_DMMAX        3
  69
  70 static int kvm_swap_nl_cached = 0;
  71 static int nswdev;
  72 static int unswdev;
  73 static int dmmax;
  74
  75 static void getswapinfo_radix(kvm_t *kd, struct kvm_swap *swap_ary,
  76                               int swap_max, int flags);
  77
  78 #define SVAR(var) __STRING(var) /* to force expansion */
  79 #define KGET(idx, var)                                                  \
  80         KGET1(idx, &var, sizeof(var), SVAR(var))
  81 #define KGET1(idx, p, s, msg)                                           \
  82         KGET2(kvm_swap_nl[idx].n_value, p, s, msg)
  83 #define KGET2(addr, p, s, msg)                                          \
  84         if (kvm_read(kd, (u_long)(addr), p, s) != s)                    \
  85                 warnx("cannot read %s: %s", msg, kvm_geterr(kd))
  86 #define KGETN(idx, var)                                                 \
  87         KGET1N(idx, &var, sizeof(var), SVAR(var))
  88 #define KGET1N(idx, p, s, msg)                                          \
  89         KGET2N(kvm_swap_nl[idx].n_value, p, s, msg)
  90 #define KGET2N(addr, p, s, msg)                                         \
  91         ((kvm_read(kd, (u_long)(addr), p, s) == s) ? 1 : 0)
  92 #define KGETRET(addr, p, s, msg)                                        \
  93         if (kvm_read(kd, (u_long)(addr), p, s) != s) {                  \
  94                 warnx("cannot read %s: %s", msg, kvm_geterr(kd));       \
  95                 return (0);                                             \
  96         }
  97
  98 int
  99 kvm_getswapinfo(
 100         kvm_t *kd,
 101         struct kvm_swap *swap_ary,
 102         int swap_max,
 103         int flags
 104 ) {
 105         int ti = 0;
 106
 107         /*
 108          * clear cache
 109          */
 110         if (kd == NULL) {
 111                 kvm_swap_nl_cached = 0;
 112                 return(0);
 113         }
 114
 115         /*
 116          * namelist
 117          */
 118         if (kvm_swap_nl_cached == 0) {
 119                 struct swdevt *sw;
 120
 121                 if (kvm_nlist(kd, kvm_swap_nl) < 0)
 122                         return(-1);
 123
 124                 /*
 125                  * required entries
 126                  */
 127
 128                 if (
 129                     kvm_swap_nl[NL_SWDEVT].n_value == 0 ||
 130                     kvm_swap_nl[NL_NSWDEV].n_value == 0 ||
 131                     kvm_swap_nl[NL_DMMAX].n_value == 0 ||
 132                     kvm_swap_nl[NL_SWAPBLIST].n_type == 0
 133                 ) {
 134                         return(-1);
 135                 }
 136
 137                 /*
 138                  * get globals, type of swap
 139                  */
 140
 141                 KGET(NL_NSWDEV, nswdev);
 142                 KGET(NL_DMMAX, dmmax);
 143
 144                 /*
 145                  * figure out how many actual swap devices are enabled
 146                  */
 147
 148                 KGET(NL_SWDEVT, sw);
 149                 for (unswdev = nswdev - 1; unswdev >= 0; --unswdev) {
 150                         struct swdevt swinfo;
 151
 152                         KGET2(&sw[unswdev], &swinfo, sizeof(swinfo), "swinfo");
 153                         if (swinfo.sw_nblks)
 154                                 break;
 155                 }
 156                 ++unswdev;
 157
 158                 kvm_swap_nl_cached = 1;
 159         }
 160
 161
 162         {
 163                 struct swdevt *sw;
 164                 int i;
 165
 166                 ti = unswdev;
 167                 if (ti >= swap_max)
 168                         ti = swap_max - 1;
 169
 170                 if (ti >= 0)
 171                         bzero(swap_ary, sizeof(struct kvm_swap) * (ti + 1));
 172
 173                 KGET(NL_SWDEVT, sw);
 174                 for (i = 0; i < unswdev; ++i) {
 175                         struct swdevt swinfo;
 176                         int ttl;
 177
 178                         KGET2(&sw[i], &swinfo, sizeof(swinfo), "swinfo");
 179
 180                         /*
 181                          * old style: everything in DEV_BSIZE'd chunks,
 182                          * convert to pages.
 183                          *
 184                          * new style: swinfo in DEV_BSIZE'd chunks but dmmax
 185                          * in pages.
 186                          *
 187                          * The first dmmax is never allocating to avoid
 188                          * trashing the disklabels
 189                          */
 190
 191                         ttl = swinfo.sw_nblks - dmmax;
 192
 193                         if (ttl == 0)
 194                                 continue;
 195
 196                         if (i < ti) {
 197                                 swap_ary[i].ksw_total = ttl;
 198                                 swap_ary[i].ksw_used = ttl;
 199                                 swap_ary[i].ksw_flags = swinfo.sw_flags;
 200                                 if (swinfo.sw_dev == NODEV) {
 201                                         snprintf(
 202                                             swap_ary[i].ksw_devname,
 203                                             sizeof(swap_ary[i].ksw_devname),
 204                                             "%s",
 205                                             "[NFS swap]"
 206                                         );
 207                                 } else {
 208                                         snprintf(
 209                                             swap_ary[i].ksw_devname,
 210                                             sizeof(swap_ary[i].ksw_devname),
 211                                             "%s%s",
 212                                             ((flags & SWIF_DEV_PREFIX) ? _PATH_DEV : ""),
 213                                             devname(swinfo.sw_dev, S_IFCHR)
 214                                         );
 215                                 }
 216                         }
 217                         if (ti >= 0) {
 218                                 swap_ary[ti].ksw_total += ttl;
 219                                 swap_ary[ti].ksw_used += ttl;
 220                         }
 221                 }
 222         }
 223
 224         getswapinfo_radix(kd, swap_ary, swap_max, flags);
 225         return(ti);
 226 }
 227
 228 /*
 229  * scanradix() - support routine for radix scanner
 230  */
 231
 232 #define TABME   tab, tab, ""
 233
 234 static int
 235 scanradix(
 236         blmeta_t *scan,
 237         daddr_t blk,
 238         daddr_t radix,
 239         daddr_t skip,
 240         daddr_t count,
 241         kvm_t *kd,
 242         int dmmax,
 243         int nswdev,
 244         struct kvm_swap *swap_ary,
 245         int swap_max,
 246         int tab,
 247         int flags
 248 ) {
 249         blmeta_t meta;
 250         int ti = (unswdev >= swap_max) ? swap_max - 1 : unswdev;
 251
 252         KGET2(scan, &meta, sizeof(meta), "blmeta_t");
 253
 254         /*
 255          * Terminator
 256          */
 257         if (meta.bm_bighint == (daddr_t)-1) {
 258                 if (flags & SWIF_DUMP_TREE) {
 259                         printf("%*.*s(0x%06x,%d) Terminator\n",
 260                             TABME,
 261                             blk,
 262                             radix
 263                         );
 264                 }
 265                 return(-1);
 266         }
 267
 268         if (radix == BLIST_BMAP_RADIX) {
 269                 /*
 270                  * Leaf bitmap
 271                  */
 272                 int i;
 273
 274                 if (flags & SWIF_DUMP_TREE) {
 275                         printf("%*.*s(0x%06x,%d) Bitmap %08x big=%d\n",
 276                             TABME,
 277                             blk,
 278                             radix,
 279                             (int)meta.u.bmu_bitmap,
 280                             meta.bm_bighint
 281                         );
 282                 }
 283
 284                 /*
 285                  * If not all allocated, count.
 286                  */
 287                 if (meta.u.bmu_bitmap != 0) {
 288                         for (i = 0; i < BLIST_BMAP_RADIX && i < count; ++i) {
 289                                 /*
 290                                  * A 0 bit means allocated
 291                                  */
 292                                 if ((meta.u.bmu_bitmap & (1 << i))) {
 293                                         int t = 0;
 294
 295                                         if (nswdev)
 296                                                 t = (blk + i) / dmmax % nswdev;
 297                                         if (t < ti)
 298                                                 --swap_ary[t].ksw_used;
 299                                         if (ti >= 0)
 300                                                 --swap_ary[ti].ksw_used;
 301                                 }
 302                         }
 303                 }
 304         } else if (meta.u.bmu_avail == radix) {
 305                 /*
 306                  * Meta node if all free
 307                  */
 308                 if (flags & SWIF_DUMP_TREE) {
 309                         printf("%*.*s(0x%06x,%d) Submap ALL-FREE {\n",
 310                             TABME,
 311                             blk,
 312                             radix
 313                         );
 314                 }
 315                 /*
 316                  * Note: both dmmax and radix are powers of 2.  However, dmmax
 317                  * may be larger then radix so use a smaller increment if
 318                  * necessary.
 319                  */
 320                 {
 321                         int t;
 322                         int tinc = dmmax;
 323
 324                         while (tinc > radix)
 325                                 tinc >>= 1;
 326
 327                         for (t = blk; t < blk + radix; t += tinc) {
 328                                 int u = (nswdev) ? (t / dmmax % nswdev) : 0;
 329
 330                                 if (u < ti)
 331                                         swap_ary[u].ksw_used -= tinc;
 332                                 if (ti >= 0)
 333                                         swap_ary[ti].ksw_used -= tinc;
 334                         }
 335                 }
 336         } else if (meta.u.bmu_avail == 0) {
 337                 /*
 338                  * Meta node if all used
 339                  */
 340                 if (flags & SWIF_DUMP_TREE) {
 341                         printf("%*.*s(0x%06x,%d) Submap ALL-ALLOCATED\n",
 342                             TABME,
 343                             blk,
 344                             radix
 345                         );
 346                 }
 347         } else {
 348                 /*
 349                  * Meta node if not all free
 350                  */
 351                 int i;
 352                 int next_skip;
 353
 354                 if (flags & SWIF_DUMP_TREE) {
 355                         printf("%*.*s(0x%06x,%d) Submap avail=%d big=%d {\n",
 356                             TABME,
 357                             blk,
 358                             radix,
 359                             (int)meta.u.bmu_avail,
 360                             meta.bm_bighint
 361                         );
 362                 }
 363
 364                 radix /= BLIST_META_RADIX;
 365                 next_skip = skip / BLIST_META_RADIX;
 366
 367                 for (i = 1; i <= skip; i += next_skip) {
 368                         int r;
 369                         daddr_t vcount = (count > radix) ? radix : count;
 370
 371                         r = scanradix(
 372                             &scan[i],
 373                             blk,
 374                             radix,
 375                             next_skip - 1,
 376                             vcount,
 377                             kd,
 378                             dmmax,
 379                             nswdev,
 380                             swap_ary,
 381                             swap_max,
 382                             tab + 4,
 383                             flags
 384                         );
 385                         if (r < 0)
 386                                 break;
 387                         blk += radix;
 388                 }
 389                 if (flags & SWIF_DUMP_TREE) {
 390                         printf("%*.*s}\n", TABME);
 391                 }
 392         }
 393         return(0);
 394 }
 395
 396 static void
 397 getswapinfo_radix(kvm_t *kd, struct kvm_swap *swap_ary, int swap_max, int flags)
 398 {
 399         struct blist *swapblist = NULL;
 400         struct blist blcopy = { 0 };
 401
 402         KGET(NL_SWAPBLIST, swapblist);
 403
 404         if (swapblist == NULL) {
 405                 if (flags & SWIF_DUMP_TREE)
 406                         printf("radix tree: NULL - no swap in system\n");
 407                 return;
 408         }
 409
 410         KGET2(swapblist, &blcopy, sizeof(blcopy), "*swapblist");
 411
 412         if (flags & SWIF_DUMP_TREE) {
 413                 printf("radix tree: %d/%d/%d blocks, %dK wired\n",
 414                         blcopy.bl_free,
 415                         blcopy.bl_blocks,
 416                         blcopy.bl_radix,
 417                         (int)((blcopy.bl_rootblks * sizeof(blmeta_t) + 1023)/
 418                             1024)
 419                 );
 420         }
 421         scanradix(
 422             blcopy.bl_root,
 423             0,
 424             blcopy.bl_radix,
 425             blcopy.bl_skip,
 426             blcopy.bl_rootblks,
 427             kd,
 428             dmmax,
 429             nswdev,
 430             swap_ary,
 431             swap_max,
 432             0,
 433             flags
 434         );
 435 }