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
  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
  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);
  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         spinlock_init(&(ktp->kt_lock), "kt_lock");
  94
  95         ktp->kt_entries  = ktep;
  96         ktp->kt_nentries = nentries;
  97         ktp->kt_index    = 0;
  98         ktp->kt_rollover = 0;
  99         return ktp;
 100 }
 101
 102
 103 /*
 104  * ktrace_free()
 105  *
 106  * Free up the ktrace header and buffer.  It is up to the caller
 107  * to ensure that no-one is referencing it.
 108  */
 109 void
 110 ktrace_free(ktrace_t *ktp)
 111 {
 112         int     entries_size;
 113
 114         if (ktp == (ktrace_t *)NULL)
 115                 return;
 116
 117         spinlock_destroy(&ktp->kt_lock);
 118
 119         /*
 120          * Special treatment for the Vnode trace buffer.
 121          */
 122         if (ktp->kt_nentries == ktrace_zentries) {
 123                 kmem_zone_free(ktrace_ent_zone, ktp->kt_entries);
 124         } else {
 125                 entries_size = (int)(ktp->kt_nentries * sizeof(ktrace_entry_t));
 126
 127                 kmem_free(ktp->kt_entries, entries_size);
 128         }
 129
 130         kmem_zone_free(ktrace_hdr_zone, ktp);
 131 }
 132
 133
 134 /*
 135  * Enter the given values into the "next" entry in the trace buffer.
 136  * kt_index is always the index of the next entry to be filled.
 137  */
 138 void
 139 ktrace_enter(
 140         ktrace_t        *ktp,
 141         void            *val0,
 142         void            *val1,
 143         void            *val2,
 144         void            *val3,
 145         void            *val4,
 146         void            *val5,
 147         void            *val6,
 148         void            *val7,
 149         void            *val8,
 150         void            *val9,
 151         void            *val10,
 152         void            *val11,
 153         void            *val12,
 154         void            *val13,
 155         void            *val14,
 156         void            *val15)
 157 {
 158         static DEFINE_SPINLOCK(wrap_lock);
 159         unsigned long   flags;
 160         int             index;
 161         ktrace_entry_t  *ktep;
 162
 163         ASSERT(ktp != NULL);
 164
 165         /*
 166          * Grab an entry by pushing the index up to the next one.
 167          */
 168         spin_lock_irqsave(&wrap_lock, flags);
 169         index = ktp->kt_index;
 170         if (++ktp->kt_index == ktp->kt_nentries)
 171                 ktp->kt_index = 0;
 172         spin_unlock_irqrestore(&wrap_lock, flags);
 173
 174         if (!ktp->kt_rollover && index == ktp->kt_nentries - 1)
 175                 ktp->kt_rollover = 1;
 176
 177         ASSERT((index >= 0) && (index < ktp->kt_nentries));
 178
 179         ktep = &(ktp->kt_entries[index]);
 180
 181         ktep->val[0]  = val0;
 182         ktep->val[1]  = val1;
 183         ktep->val[2]  = val2;
 184         ktep->val[3]  = val3;
 185         ktep->val[4]  = val4;
 186         ktep->val[5]  = val5;
 187         ktep->val[6]  = val6;
 188         ktep->val[7]  = val7;
 189         ktep->val[8]  = val8;
 190         ktep->val[9]  = val9;
 191         ktep->val[10] = val10;
 192         ktep->val[11] = val11;
 193         ktep->val[12] = val12;
 194         ktep->val[13] = val13;
 195         ktep->val[14] = val14;
 196         ktep->val[15] = val15;
 197 }
 198
 199 /*
 200  * Return the number of entries in the trace buffer.
 201  */
 202 int
 203 ktrace_nentries(
 204         ktrace_t        *ktp)
 205 {
 206         if (ktp == NULL) {
 207                 return 0;
 208         }
 209
 210         return (ktp->kt_rollover ? ktp->kt_nentries : ktp->kt_index);
 211 }
 212
 213 /*
 214  * ktrace_first()
 215  *
 216  * This is used to find the start of the trace buffer.
 217  * In conjunction with ktrace_next() it can be used to
 218  * iterate through the entire trace buffer.  This code does
 219  * not do any locking because it is assumed that it is called
 220  * from the debugger.
 221  *
 222  * The caller must pass in a pointer to a ktrace_snap
 223  * structure in which we will keep some state used to
 224  * iterate through the buffer.  This state must not touched
 225  * by any code outside of this module.
 226  */
 227 ktrace_entry_t *
 228 ktrace_first(ktrace_t   *ktp, ktrace_snap_t     *ktsp)
 229 {
 230         ktrace_entry_t  *ktep;
 231         int             index;
 232         int             nentries;
 233
 234         if (ktp->kt_rollover)
 235                 index = ktp->kt_index;
 236         else
 237                 index = 0;
 238
 239         ktsp->ks_start = index;
 240         ktep = &(ktp->kt_entries[index]);
 241
 242         nentries = ktrace_nentries(ktp);
 243         index++;
 244         if (index < nentries) {
 245                 ktsp->ks_index = index;
 246         } else {
 247                 ktsp->ks_index = 0;
 248                 if (index > nentries)
 249                         ktep = NULL;
 250         }
 251         return ktep;
 252 }
 253
 254 /*
 255  * ktrace_next()
 256  *
 257  * This is used to iterate through the entries of the given
 258  * trace buffer.  The caller must pass in the ktrace_snap_t
 259  * structure initialized by ktrace_first().  The return value
 260  * will be either a pointer to the next ktrace_entry or NULL
 261  * if all of the entries have been traversed.
 262  */
 263 ktrace_entry_t *
 264 ktrace_next(
 265         ktrace_t        *ktp,
 266         ktrace_snap_t   *ktsp)
 267 {
 268         int             index;
 269         ktrace_entry_t  *ktep;
 270
 271         index = ktsp->ks_index;
 272         if (index == ktsp->ks_start) {
 273                 ktep = NULL;
 274         } else {
 275                 ktep = &ktp->kt_entries[index];
 276         }
 277
 278         index++;
 279         if (index == ktrace_nentries(ktp)) {
 280                 ktsp->ks_index = 0;
 281         } else {
 282                 ktsp->ks_index = index;
 283         }
 284
 285         return ktep;
 286 }
 287
 288 /*
 289  * ktrace_skip()
 290  *
 291  * Skip the next "count" entries and return the entry after that.
 292  * Return NULL if this causes us to iterate past the beginning again.
 293  */
 294 ktrace_entry_t *
 295 ktrace_skip(
 296         ktrace_t        *ktp,
 297         int             count,
 298         ktrace_snap_t   *ktsp)
 299 {
 300         int             index;
 301         int             new_index;
 302         ktrace_entry_t  *ktep;
 303         int             nentries = ktrace_nentries(ktp);
 304
 305         index = ktsp->ks_index;
 306         new_index = index + count;
 307         while (new_index >= nentries) {
 308                 new_index -= nentries;
 309         }
 310         if (index == ktsp->ks_start) {
 311                 /*
 312                  * We've iterated around to the start, so we're done.
 313                  */
 314                 ktep = NULL;
 315         } else if ((new_index < index) && (index < ktsp->ks_index)) {
 316                 /*
 317                  * We've skipped past the start again, so we're done.
 318                  */
 319                 ktep = NULL;
 320                 ktsp->ks_index = ktsp->ks_start;
 321         } else {
 322                 ktep = &(ktp->kt_entries[new_index]);
 323                 new_index++;
 324                 if (new_index == nentries) {
 325                         ktsp->ks_index = 0;
 326                 } else {
 327                         ktsp->ks_index = new_index;
 328                 }
 329         }
 330         return ktep;
 331 }