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 17:15:35 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 #include <sys/sysctl.h>
  47 #include <vm/vm_param.h>
  48
  49 #include <err.h>
  50 #include <fcntl.h>
  51 #include <kvm.h>
  52 #include <nlist.h>
  53 #include <paths.h>
  54 #include <stdio.h>
  55 #include <stdlib.h>
  56 #include <string.h>
  57 #include <unistd.h>
  58 #include <limits.h>
  59
  60 #include "kvm_private.h"
  61
  62 static struct nlist kvm_swap_nl[] = {
  63         { "_swapblist" },       /* new radix swap list          */
  64         { "_swdevt" },          /* list of swap devices and sizes */
  65         { "_nswdev" },          /* number of swap devices */
  66         { "_dmmax" },           /* maximum size of a swap block */
  67         { "" }
  68 };
  69
  70 #define NL_SWAPBLIST    0
  71 #define NL_SWDEVT       1
  72 #define NL_NSWDEV       2
  73 #define NL_DMMAX        3
  74
  75 static int kvm_swap_nl_cached = 0;
  76 static int nswdev;
  77 static int unswdev;
  78 static int dmmax;
  79
  80 static int nlist_init(kvm_t *kd);
  81 static void dump_blist(kvm_t *kd);
  82 static int kvm_getswapinfo_sysctl(kvm_t *kd, struct kvm_swap *swap_ary,
  83                               int swap_max, int flags);
  84
  85 #define SVAR(var) __STRING(var) /* to force expansion */
  86 #define KGET(idx, var)                                                  \
  87         KGET1(idx, &var, sizeof(var), SVAR(var))
  88 #define KGET1(idx, p, s, msg)                                           \
  89         KGET2(kvm_swap_nl[idx].n_value, p, s, msg)
  90 #define KGET2(addr, p, s, msg)                                          \
  91         if (kvm_read(kd, (u_long)(addr), p, s) != s)                    \
  92                 warnx("cannot read %s: %s", msg, kvm_geterr(kd))
  93 #define KGETN(idx, var)                                                 \
  94         KGET1N(idx, &var, sizeof(var), SVAR(var))
  95 #define KGET1N(idx, p, s, msg)                                          \
  96         KGET2N(kvm_swap_nl[idx].n_value, p, s, msg)
  97 #define KGET2N(addr, p, s, msg)                                         \
  98         ((kvm_read(kd, (u_long)(addr), p, s) == s) ? 1 : 0)
  99 #define KGETRET(addr, p, s, msg)                                        \
 100         if (kvm_read(kd, (u_long)(addr), p, s) != s) {                  \
 101                 warnx("cannot read %s: %s", msg, kvm_geterr(kd));       \
 102                 return (0);                                             \
 103         }
 104
 105 #define GETSWDEVNAME(dev, str, flags)                                   \
 106         if (dev == NODEV) {                                             \
 107                 strlcpy(str, "[NFS swap]", sizeof(str));                \
 108         } else {                                                        \
 109                 snprintf(                                               \
 110                     str, sizeof(str), "%s%s",                           \
 111                     ((flags & SWIF_DEV_PREFIX) ? _PATH_DEV : ""),       \
 112                     devname(dev, S_IFCHR)                               \
 113                 );                                                      \
 114         }
 115
 116 int
 117 kvm_getswapinfo(
 118         kvm_t *kd,
 119         struct kvm_swap *swap_ary,
 120         int swap_max,
 121         int flags
 122 ) {
 123         int i, ti, swi;
 124         int ttl;
 125         struct swdevt *sw;
 126         struct swdevt swinfo;
 127
 128         /*
 129          * clear cache
 130          */
 131         if (kd == NULL) {
 132                 kvm_swap_nl_cached = 0;
 133                 return(0);
 134         }
 135
 136         if (swap_max < 1)
 137                 return (-1);
 138
 139         /*
 140          * Use sysctl if possible
 141          */
 142         if (kvm_ishost(kd) && (flags & SWIF_DUMP_TREE) == 0) {
 143                 ti = kvm_getswapinfo_sysctl(kd, swap_ary, swap_max, flags);
 144                 if (ti >= 0)
 145                         return(ti);
 146         }
 147
 148         /*
 149          * namelist
 150          */
 151         if (!nlist_init(kd))
 152                 return (-1);
 153
 154         swi = unswdev;
 155         if (swi >= swap_max)
 156                 swi = swap_max - 1;
 157
 158         bzero(swap_ary, sizeof(struct kvm_swap) * (swi + 1));
 159
 160         KGET(NL_SWDEVT, sw);
 161         for (i = ti = 0; i < nswdev; ++i) {
 162                 KGET2(&sw[i], &swinfo, sizeof(swinfo), "swinfo");
 163
 164                 if (swinfo.sw_nblks == 0)
 165                         continue;
 166
 167                 /*
 168                  * The first dmmax is never allocated to avoid
 169                  * trashing the disklabels.
 170                  */
 171                 ttl = swinfo.sw_nblks - dmmax;
 172                 if (ttl == 0)
 173                         continue;
 174
 175                 swap_ary[swi].ksw_total += ttl;
 176                 swap_ary[swi].ksw_used += swinfo.sw_nused;
 177
 178                 if (ti < swi) {
 179                         swap_ary[ti].ksw_total = ttl;
 180                         swap_ary[ti].ksw_used = swinfo.sw_nused;
 181                         swap_ary[ti].ksw_flags = swinfo.sw_flags;
 182                         GETSWDEVNAME(swinfo.sw_dev, swap_ary[ti].ksw_devname,
 183                             flags);
 184                         ++ti;
 185                 }
 186         }
 187
 188         if (flags & SWIF_DUMP_TREE)
 189                 dump_blist(kd);
 190         return (swi);
 191 }
 192
 193 static int
 194 nlist_init(kvm_t *kd)
 195 {
 196         int i;
 197         struct swdevt *sw;
 198         struct swdevt swinfo;
 199
 200         if (kvm_swap_nl_cached)
 201                 return (1);
 202
 203         if (kvm_nlist(kd, kvm_swap_nl) < 0)
 204                 return (0);
 205
 206         /*
 207          * required entries
 208          */
 209         if (kvm_swap_nl[NL_SWDEVT].n_value == 0 ||
 210             kvm_swap_nl[NL_NSWDEV].n_value == 0 ||
 211             kvm_swap_nl[NL_DMMAX].n_value == 0 ||
 212             kvm_swap_nl[NL_SWAPBLIST].n_type == 0) {
 213                 return (0);
 214         }
 215
 216         /*
 217          * get globals, type of swap
 218          */
 219         KGET(NL_NSWDEV, nswdev);
 220         KGET(NL_DMMAX, dmmax);
 221
 222         /*
 223          * figure out how many actual swap devices are enabled
 224          */
 225         KGET(NL_SWDEVT, sw);
 226         for (i = unswdev = 0; i < nswdev; ++i) {
 227                 KGET2(&sw[i], &swinfo, sizeof(swinfo), "swinfo");
 228                 if (swinfo.sw_nblks)
 229                         ++unswdev;
 230
 231         }
 232
 233         kvm_swap_nl_cached = 1;
 234         return (1);
 235 }
 236
 237 /*
 238  * scanradix() - support routine for radix scanner
 239  */
 240
 241 #define TABME   tab, tab, ""
 242
 243 static int
 244 scanradix(
 245         blmeta_t *scan,
 246         blmeta_t *scan_cache,
 247         swblk_t blk,
 248         int64_t radix,
 249         swblk_t skip,
 250         swblk_t count,
 251         kvm_t *kd,
 252         int dmmax,
 253         int nswdev,
 254         int64_t *availp,
 255         int tab
 256 ) {
 257         blmeta_t meta;
 258         blmeta_t scan_array[BLIST_BMAP_RADIX];
 259         int i;
 260
 261         if (scan_cache) {
 262                 meta = *scan_cache;
 263         } else if (skip == BLIST_META_RADIX) {
 264                 if (kvm_read(kd, (u_long)scan, scan_array, sizeof(scan_array)) != sizeof(scan_array)) {
 265                         warnx("cannot read %s: %s", "blmeta_t", kvm_geterr(kd));
 266                         bzero(scan_array, sizeof(scan_array));
 267                 }
 268                 meta = scan_array[0];
 269         } else {
 270                 KGET2(scan, &meta, sizeof(meta), "blmeta_t");
 271         }
 272
 273         /*
 274          * Terminator
 275          */
 276         if (meta.bm_bighint == (swblk_t)-1) {
 277                 printf("%*.*s(0x%06x,%lld) Terminator\n",
 278                     TABME,
 279                     blk,
 280                     (long long)radix
 281                 );
 282                 return(-1);
 283         }
 284
 285         if (radix == BLIST_BMAP_RADIX) {
 286                 /*
 287                  * Leaf bitmap
 288                  */
 289                 printf("%*.*s(0x%06x,%lld) Bitmap %08x big=%d\n",
 290                     TABME,
 291                     blk,
 292                     (long long)radix,
 293                     (int)meta.u.bmu_bitmap,
 294                     meta.bm_bighint
 295                 );
 296
 297                 if (meta.u.bmu_bitmap) {
 298                         for (i = 0; i < BLIST_BMAP_RADIX; ++i) {
 299                                 if (meta.u.bmu_bitmap & (1 << i))
 300                                         ++*availp;
 301                         }
 302                 }
 303         } else if (meta.u.bmu_avail == radix) {
 304                 /*
 305                  * Meta node if all free
 306                  */
 307                 printf("%*.*s(0x%06x,%lld) Submap ALL-FREE (big=%d) {\n",
 308                     TABME,
 309                     blk,
 310                     (long long)radix,
 311                     meta.bm_bighint
 312                 );
 313                 *availp += radix;
 314         } else if (meta.u.bmu_avail == 0) {
 315                 /*
 316                  * Meta node if all used
 317                  */
 318                 printf("%*.*s(0x%06x,%lld) Submap ALL-ALLOCATED (big=%d)\n",
 319                     TABME,
 320                     blk,
 321                     (long long)radix,
 322                     meta.bm_bighint
 323                 );
 324         } else {
 325                 /*
 326                  * Meta node if not all free
 327                  */
 328                 int i;
 329                 int next_skip;
 330                 int64_t avail_tmp = 0;
 331
 332                 printf("%*.*s(0x%06x,%lld) Submap avail=%d big=%d {\n",
 333                     TABME,
 334                     blk,
 335                     (long long)radix,
 336                     (int)meta.u.bmu_avail,
 337                     meta.bm_bighint
 338                 );
 339
 340                 radix /= BLIST_META_RADIX;
 341                 next_skip = skip / BLIST_META_RADIX;
 342
 343                 for (i = 1; i <= skip; i += next_skip) {
 344                         int r;
 345                         swblk_t vcount = (count > radix) ?
 346                                         (swblk_t)radix : count;
 347
 348                         r = scanradix(
 349                             &scan[i],
 350                             ((next_skip == 1) ? &scan_array[i] : NULL),
 351                             blk,
 352                             radix,
 353                             next_skip - 1,
 354                             vcount,
 355                             kd,
 356                             dmmax,
 357                             nswdev,
 358                             &avail_tmp,
 359                             tab + 4
 360                         );
 361                         if (r < 0)
 362                                 break;
 363                         blk += (swblk_t)radix;
 364                 }
 365                 *availp += avail_tmp;
 366                 if (avail_tmp == meta.u.bmu_avail)
 367                         printf("%*.*s}\n", TABME);
 368                 else
 369                         printf("%*.*s} (AVAIL MISMATCH %jd/%jd\n",
 370                                 TABME,
 371                                 (intmax_t)avail_tmp,
 372                                 (intmax_t)meta.u.bmu_avail);
 373         }
 374         return(0);
 375 }
 376
 377 static void
 378 dump_blist(kvm_t *kd)
 379 {
 380         struct blist *swapblist = NULL;
 381         struct blist blcopy = { 0 };
 382         int64_t avail = 0;
 383
 384         KGET(NL_SWAPBLIST, swapblist);
 385
 386         if (swapblist == NULL) {
 387                 printf("radix tree: NULL - no swap in system\n");
 388                 return;
 389         }
 390
 391         KGET2(swapblist, &blcopy, sizeof(blcopy), "*swapblist");
 392
 393         printf("radix tree: %d/%d/%lld blocks, %dK wired\n",
 394                 blcopy.bl_free,
 395                 blcopy.bl_blocks,
 396                 (long long)blcopy.bl_radix,
 397                 (int)((blcopy.bl_rootblks * sizeof(blmeta_t) + 1023)/
 398                     1024)
 399         );
 400
 401         scanradix(
 402             blcopy.bl_root,
 403             NULL,
 404             0,
 405             blcopy.bl_radix,
 406             blcopy.bl_skip,
 407             blcopy.bl_rootblks,
 408             kd,
 409             dmmax,
 410             nswdev,
 411             &avail,
 412             0
 413         );
 414         printf("final availability: %jd\n", (intmax_t)avail);
 415 }
 416
 417 static
 418 int
 419 kvm_getswapinfo_sysctl(kvm_t *kd, struct kvm_swap *swap_ary,
 420                        int swap_max, int flags)
 421 {
 422         size_t bytes = 0;
 423         size_t ksize;
 424         int ti;
 425         int swi;
 426         int n;
 427         int i;
 428         char *xswbuf;
 429         struct xswdev *xsw;
 430
 431         if (sysctlbyname("vm.swap_info_array", NULL, &bytes, NULL, 0) < 0)
 432                 return(-1);
 433         if (bytes == 0)
 434                 return(-1);
 435
 436         xswbuf = malloc(bytes);
 437         if (sysctlbyname("vm.swap_info_array", xswbuf, &bytes, NULL, 0) < 0) {
 438                 free(xswbuf);
 439                 return(-1);
 440         }
 441         if (bytes == 0) {
 442                 free(xswbuf);
 443                 return(-1);
 444         }
 445
 446         /*
 447          * Calculate size of xsw entry returned by kernel (it can be larger
 448          * than the one we have if there is a version mismatch).
 449          */
 450         ksize = ((struct xswdev *)xswbuf)->xsw_size;
 451         n = (int)(bytes / ksize);
 452
 453         /*
 454          * Calculate the number of live swap devices and calculate
 455          * the swap_ary[] index used for the cumulative result (swi)
 456          */
 457         for (i = swi = 0; i < n; ++i) {
 458                 xsw = (void *)((char *)xswbuf + i * ksize);
 459                 if ((xsw->xsw_flags & SW_FREED) == 0)
 460                         continue;
 461                 ++swi;
 462         }
 463         if (swi >= swap_max)
 464                 swi = swap_max - 1;
 465
 466         bzero(swap_ary, sizeof(struct kvm_swap) * (swi + 1));
 467
 468         /*
 469          * Accumulate results.  If the provided swap_ary[] is too
 470          * small will only populate up to the available entries,
 471          * but we always populate the cumulative results entry.
 472          */
 473         for (i = ti = 0; i < n; ++i) {
 474                 xsw = (void *)((char *)xswbuf + i * ksize);
 475
 476                 if ((xsw->xsw_flags & SW_FREED) == 0)
 477                         continue;
 478
 479                 swap_ary[swi].ksw_total += xsw->xsw_nblks;
 480                 swap_ary[swi].ksw_used += xsw->xsw_used;
 481
 482                 if (ti < swi) {
 483                         swap_ary[ti].ksw_total = xsw->xsw_nblks;
 484                         swap_ary[ti].ksw_used = xsw->xsw_used;
 485                         swap_ary[ti].ksw_flags = xsw->xsw_flags;
 486                         GETSWDEVNAME(xsw->xsw_dev, swap_ary[ti].ksw_devname,
 487                             flags);
 488                         ++ti;
 489                 }
 490         }
 491
 492         free(xswbuf);
 493         return(swi);
 494 }