fs/xfs/support/ktrace.c

   1 /*
   2  * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
   3  * All Rights Reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18 #include <xfs.h>
  19
  20 static kmem_zone_t *ktrace_hdr_zone;
  21 static kmem_zone_t *ktrace_ent_zone;
  22 static int          ktrace_zentries;
  23
  24 void __init
  25 ktrace_init(int zentries)
  26 {
  27         ktrace_zentries = zentries;
  28
  29         ktrace_hdr_zone = kmem_zone_init(sizeof(ktrace_t),
  30                                         "ktrace_hdr");
  31         ASSERT(ktrace_hdr_zone);
  32
  33         ktrace_ent_zone = kmem_zone_init(ktrace_zentries
  34                                         * sizeof(ktrace_entry_t),
  35                                         "ktrace_ent");
  36         ASSERT(ktrace_ent_zone);
  37 }
  38
  39 void __exit
  40 ktrace_uninit(void)
  41 {
  42         kmem_zone_destroy(ktrace_hdr_zone);
  43         kmem_zone_destroy(ktrace_ent_zone);
  44 }
  45
  46 /*
  47  * ktrace_alloc()
  48  *
  49  * Allocate a ktrace header and enough buffering for the given
  50  * number of entries.
  51  */
  52 ktrace_t *
  53 ktrace_alloc(int nentries, unsigned int __nocast sleep)
  54 {
  55         ktrace_t        *ktp;
  56         ktrace_entry_t  *ktep;
  57
  58         ktp = (ktrace_t*)kmem_zone_alloc(ktrace_hdr_zone, sleep);
  59
  60         if (ktp == (ktrace_t*)NULL) {
  61                 /*
  62                  * KM_SLEEP callers don't expect failure.
  63                  */
  64                 if (sleep & KM_SLEEP)
  65                         panic("ktrace_alloc: NULL memory on KM_SLEEP request!");
  66
  67                 return NULL;
  68         }
  69
  70         /*
  71          * Special treatment for buffers with the ktrace_zentries entries
  72          */
  73         if (nentries == ktrace_zentries) {
  74                 ktep = (ktrace_entry_t*)kmem_zone_zalloc(ktrace_ent_zone,
  75                                                             sleep);
  76         } else {
  77                 ktep = (ktrace_entry_t*)kmem_zalloc((nentries * sizeof(*ktep)),
  78                                                             sleep | KM_LARGE);
  79         }
  80
  81         if (ktep == NULL) {
  82                 /*
  83                  * KM_SLEEP callers don't expect failure.
  84                  */
  85                 if (sleep & KM_SLEEP)
  86                         panic("ktrace_alloc: NULL memory on KM_SLEEP request!");
  87
  88                 kmem_free(ktp, sizeof(*ktp));
  89
  90                 return NULL;
  91         }
  92
  93         ktp->kt_entries  = ktep;
  94         ktp->kt_nentries = nentries;
  95         ktp->kt_index    = 0;
  96         ktp->kt_rollover = 0;
  97         return ktp;
  98 }
  99
 100
 101 /*
 102  * ktrace_free()
 103  *
 104  * Free up the ktrace header and buffer.  It is up to the caller
 105  * to ensure that no-one is referencing it.
 106  */
 107 void
 108 ktrace_free(ktrace_t *ktp)
 109 {
 110         int     entries_size;
 111
 112         if (ktp == (ktrace_t *)NULL)
 113                 return;
 114
 115         /*
 116          * Special treatment for the Vnode trace buffer.
 117          */
 118         if (ktp->kt_nentries == ktrace_zentries) {
 119                 kmem_zone_free(ktrace_ent_zone, ktp->kt_entries);
 120         } else {
 121                 entries_size = (int)(ktp->kt_nentries * sizeof(ktrace_entry_t));
 122
 123                 kmem_free(ktp->kt_entries, entries_size);
 124         }
 125
 126         kmem_zone_free(ktrace_hdr_zone, ktp);
 127 }
 128
 129
 130 /*
 131  * Enter the given values into the "next" entry in the trace buffer.
 132  * kt_index is always the index of the next entry to be filled.
 133  */
 134 void
 135 ktrace_enter(
 136         ktrace_t        *ktp,
 137         void            *val0,
 138         void            *val1,
 139         void            *val2,
 140         void            *val3,
 141         void            *val4,
 142         void            *val5,
 143         void            *val6,
 144         void            *val7,
 145         void            *val8,
 146         void            *val9,
 147         void            *val10,
 148         void            *val11,
 149         void            *val12,
 150         void            *val13,
 151         void            *val14,
 152         void            *val15)
 153 {
 154         static DEFINE_SPINLOCK(wrap_lock);
 155         unsigned long   flags;
 156         int             index;
 157         ktrace_entry_t  *ktep;
 158
 159         ASSERT(ktp != NULL);
 160
 161         /*
 162          * Grab an entry by pushing the index up to the next one.
 163          */
 164         spin_lock_irqsave(&wrap_lock, flags);
 165         index = ktp->kt_index;
 166         if (++ktp->kt_index == ktp->kt_nentries)
 167                 ktp->kt_index = 0;
 168         spin_unlock_irqrestore(&wrap_lock, flags);
 169
 170         if (!ktp->kt_rollover && index == ktp->kt_nentries - 1)
 171                 ktp->kt_rollover = 1;
 172
 173         ASSERT((index >= 0) && (index < ktp->kt_nentries));
 174
 175         ktep = &(ktp->kt_entries[index]);
 176
 177         ktep->val[0]  = val0;
 178         ktep->val[1]  = val1;
 179         ktep->val[2]  = val2;
 180         ktep->val[3]  = val3;
 181         ktep->val[4]  = val4;
 182         ktep->val[5]  = val5;
 183         ktep->val[6]  = val6;
 184         ktep->val[7]  = val7;
 185         ktep->val[8]  = val8;
 186         ktep->val[9]  = val9;
 187         ktep->val[10] = val10;
 188         ktep->val[11] = val11;
 189         ktep->val[12] = val12;
 190         ktep->val[13] = val13;
 191         ktep->val[14] = val14;
 192         ktep->val[15] = val15;
 193 }
 194
 195 /*
 196  * Return the number of entries in the trace buffer.
 197  */
 198 int
 199 ktrace_nentries(
 200         ktrace_t        *ktp)
 201 {
 202         if (ktp == NULL) {
 203                 return 0;
 204         }
 205
 206         return (ktp->kt_rollover ? ktp->kt_nentries : ktp->kt_index);
 207 }
 208
 209 /*
 210  * ktrace_first()
 211  *
 212  * This is used to find the start of the trace buffer.
 213  * In conjunction with ktrace_next() it can be used to
 214  * iterate through the entire trace buffer.  This code does
 215  * not do any locking because it is assumed that it is called
 216  * from the debugger.
 217  *
 218  * The caller must pass in a pointer to a ktrace_snap
 219  * structure in which we will keep some state used to
 220  * iterate through the buffer.  This state must not touched
 221  * by any code outside of this module.
 222  */
 223 ktrace_entry_t *
 224 ktrace_first(ktrace_t   *ktp, ktrace_snap_t     *ktsp)
 225 {
 226         ktrace_entry_t  *ktep;
 227         int             index;
 228         int             nentries;
 229
 230         if (ktp->kt_rollover)
 231                 index = ktp->kt_index;
 232         else
 233                 index = 0;
 234
 235         ktsp->ks_start = index;
 236         ktep = &(ktp->kt_entries[index]);
 237
 238         nentries = ktrace_nentries(ktp);
 239         index++;
 240         if (index < nentries) {
 241                 ktsp->ks_index = index;
 242         } else {
 243                 ktsp->ks_index = 0;
 244                 if (index > nentries)
 245                         ktep = NULL;
 246         }
 247         return ktep;
 248 }
 249
 250 /*
 251  * ktrace_next()
 252  *
 253  * This is used to iterate through the entries of the given
 254  * trace buffer.  The caller must pass in the ktrace_snap_t
 255  * structure initialized by ktrace_first().  The return value
 256  * will be either a pointer to the next ktrace_entry or NULL
 257  * if all of the entries have been traversed.
 258  */
 259 ktrace_entry_t *
 260 ktrace_next(
 261         ktrace_t        *ktp,
 262         ktrace_snap_t   *ktsp)
 263 {
 264         int             index;
 265         ktrace_entry_t  *ktep;
 266
 267         index = ktsp->ks_index;
 268         if (index == ktsp->ks_start) {
 269                 ktep = NULL;
 270         } else {
 271                 ktep = &ktp->kt_entries[index];
 272         }
 273
 274         index++;
 275         if (index == ktrace_nentries(ktp)) {
 276                 ktsp->ks_index = 0;
 277         } else {
 278                 ktsp->ks_index = index;
 279         }
 280
 281         return ktep;
 282 }
 283
 284 /*
 285  * ktrace_skip()
 286  *
 287  * Skip the next "count" entries and return the entry after that.
 288  * Return NULL if this causes us to iterate past the beginning again.
 289  */
 290 ktrace_entry_t *
 291 ktrace_skip(
 292         ktrace_t        *ktp,
 293         int             count,
 294         ktrace_snap_t   *ktsp)
 295 {
 296         int             index;
 297         int             new_index;
 298         ktrace_entry_t  *ktep;
 299         int             nentries = ktrace_nentries(ktp);
 300
 301         index = ktsp->ks_index;
 302         new_index = index + count;
 303         while (new_index >= nentries) {
 304                 new_index -= nentries;
 305         }
 306         if (index == ktsp->ks_start) {
 307                 /*
 308                  * We've iterated around to the start, so we're done.
 309                  */
 310                 ktep = NULL;
 311         } else if ((new_index < index) && (index < ktsp->ks_index)) {
 312                 /*
 313                  * We've skipped past the start again, so we're done.
 314                  */
 315                 ktep = NULL;
 316                 ktsp->ks_index = ktsp->ks_start;
 317         } else {
 318                 ktep = &(ktp->kt_entries[new_index]);
 319                 new_index++;
 320                 if (new_index == nentries) {
 321                         ktsp->ks_index = 0;
 322                 } else {
 323                         ktsp->ks_index = new_index;
 324                 }
 325         }
 326         return ktep;
 327 }