subr_devstat.c

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    1 /*
    2  * Copyright (c) 1997, 1998, 1999 Kenneth D. Merry.
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  * 3. The name of the author may not be used to endorse or promote products
   14  *    derived from this software without specific prior written permission.
   15  *
   16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   26  * SUCH DAMAGE.
   27  *
   28  * $FreeBSD$
   29  */
   30 
   31 #include <sys/param.h>
   32 #include <sys/kernel.h>
   33 #include <sys/systm.h>
   34 #include <sys/time.h>
   35 #include <sys/types.h>
   36 #include <sys/sysctl.h>
   37 
   38 #include <sys/devicestat.h>
   39 
   40 static int devstat_num_devs;
   41 static long devstat_generation;
   42 static int devstat_version = DEVSTAT_VERSION;
   43 static int devstat_current_devnumber;
   44 
   45 STAILQ_HEAD(devstatlist, devstat) device_statq;
   46 
   47 /*
   48  * Take a malloced and zeroed devstat structure given to us, fill it in 
   49  * and add it to the queue of devices.  
   50  */
   51 void
   52 devstat_add_entry(struct devstat *ds, const char *dev_name, 
   53                   int unit_number, u_int32_t block_size,
   54                   devstat_support_flags flags,
   55                   devstat_type_flags device_type,
   56                   devstat_priority priority)
   57 {
   58         int s;
   59         struct devstatlist *devstat_head;
   60         struct devstat *ds_tmp;
   61 
   62         if (ds == NULL)
   63                 return;
   64 
   65         if (devstat_num_devs == 0)
   66                 STAILQ_INIT(&device_statq);
   67 
   68         devstat_generation++;
   69         devstat_num_devs++;
   70 
   71         devstat_head = &device_statq;
   72 
   73         /*
   74          * Priority sort.  Each driver passes in its priority when it adds
   75          * its devstat entry.  Drivers are sorted first by priority, and
   76          * then by probe order.
   77          * 
   78          * For the first device, we just insert it, since the priority
   79          * doesn't really matter yet.  Subsequent devices are inserted into
   80          * the list using the order outlined above.
   81          */
   82         if (devstat_num_devs == 1)
   83                 STAILQ_INSERT_TAIL(devstat_head, ds, dev_links);
   84         else {
   85                 for (ds_tmp = STAILQ_FIRST(devstat_head); ds_tmp != NULL;
   86                      ds_tmp = STAILQ_NEXT(ds_tmp, dev_links)) {
   87                         struct devstat *ds_next;
   88 
   89                         ds_next = STAILQ_NEXT(ds_tmp, dev_links);
   90 
   91                         /*
   92                          * If we find a break between higher and lower
   93                          * priority items, and if this item fits in the
   94                          * break, insert it.  This also applies if the
   95                          * "lower priority item" is the end of the list.
   96                          */
   97                         if ((priority <= ds_tmp->priority)
   98                          && ((ds_next == NULL)
   99                            || (priority > ds_next->priority))) {
  100                                 STAILQ_INSERT_AFTER(devstat_head, ds_tmp, ds,
  101                                                     dev_links);
  102                                 break;
  103                         } else if (priority > ds_tmp->priority) {
  104                                 /*
  105                                  * If this is the case, we should be able
  106                                  * to insert ourselves at the head of the
  107                                  * list.  If we can't, something is wrong.
  108                                  */
  109                                 if (ds_tmp == STAILQ_FIRST(devstat_head)) {
  110                                         STAILQ_INSERT_HEAD(devstat_head,
  111                                                            ds, dev_links);
  112                                         break;
  113                                 } else {
  114                                         STAILQ_INSERT_TAIL(devstat_head,
  115                                                            ds, dev_links);
  116                                         printf("devstat_add_entry: HELP! "
  117                                                "sorting problem detected "
  118                                                "for %s%d\n", dev_name,
  119                                                unit_number);
  120                                         break;
  121                                 }
  122                         }
  123                 }
  124         }
  125 
  126         ds->device_number = devstat_current_devnumber++;
  127         ds->unit_number = unit_number;
  128         strncpy(ds->device_name, dev_name, DEVSTAT_NAME_LEN);
  129         ds->device_name[DEVSTAT_NAME_LEN - 1] = '\0';
  130         ds->block_size = block_size;
  131         ds->flags = flags;
  132         ds->device_type = device_type;
  133         ds->priority = priority;
  134 
  135         s = splclock();
  136         getmicrotime(&ds->dev_creation_time);
  137         splx(s);
  138 }
  139 
  140 /*
  141  * Remove a devstat structure from the list of devices.
  142  */
  143 void
  144 devstat_remove_entry(struct devstat *ds)
  145 {
  146         struct devstatlist *devstat_head;
  147 
  148         if (ds == NULL)
  149                 return;
  150 
  151         devstat_generation++;
  152         devstat_num_devs--;
  153 
  154         devstat_head = &device_statq;
  155 
  156         /* Remove this entry from the devstat queue */
  157         STAILQ_REMOVE(devstat_head, ds, devstat, dev_links);
  158 }
  159 
  160 /*
  161  * Record a transaction start.
  162  */
  163 void
  164 devstat_start_transaction(struct devstat *ds)
  165 {
  166         int s;
  167 
  168         /* sanity check */
  169         if (ds == NULL)
  170                 return;
  171 
  172         /*
  173          * We only want to set the start time when we are going from idle
  174          * to busy.  The start time is really the start of the latest busy
  175          * period.
  176          */
  177         if (ds->busy_count == 0) {
  178                 s = splclock(); 
  179                 getmicrouptime(&ds->start_time);
  180                 splx(s);
  181         }
  182         ds->busy_count++;
  183 }
  184 
  185 /*
  186  * Record the ending of a transaction, and incrment the various counters.
  187  */
  188 void
  189 devstat_end_transaction(struct devstat *ds, u_int32_t bytes, 
  190                         devstat_tag_type tag_type, devstat_trans_flags flags)
  191 {
  192         int s;
  193         struct timeval busy_time;
  194 
  195         /* sanity check */
  196         if (ds == NULL)
  197                 return;
  198 
  199         s = splclock();
  200         getmicrouptime(&ds->last_comp_time);
  201         splx(s);
  202 
  203         ds->busy_count--;
  204 
  205         /*
  206          * There might be some transactions (DEVSTAT_NO_DATA) that don't
  207          * transfer any data.
  208          */
  209         if (flags == DEVSTAT_READ) {
  210                 ds->bytes_read += bytes;
  211                 ds->num_reads++;
  212         } else if (flags == DEVSTAT_WRITE) {
  213                 ds->bytes_written += bytes;
  214                 ds->num_writes++;
  215         } else
  216                 ds->num_other++;
  217 
  218         /*
  219          * Keep a count of the various tag types sent.
  220          */
  221         if (tag_type != DEVSTAT_TAG_NONE)
  222                 ds->tag_types[tag_type]++;
  223 
  224         /*
  225          * We only update the busy time when we go idle.  Otherwise, this
  226          * calculation would require many more clock cycles.
  227          */
  228         if (ds->busy_count == 0) {
  229                 /* Calculate how long we were busy */
  230                 busy_time = ds->last_comp_time;
  231                 timevalsub(&busy_time, &ds->start_time);
  232 
  233                 /* Add our busy time to the total busy time. */
  234                 timevaladd(&ds->busy_time, &busy_time);
  235         } else if (ds->busy_count < 0)
  236                 printf("devstat_end_transaction: HELP!! busy_count "
  237                        "for %s%d is < 0 (%d)!\n", ds->device_name,
  238                        ds->unit_number, ds->busy_count);
  239 }
  240 
  241 /*
  242  * This is the sysctl handler for the devstat package.  The data pushed out
  243  * on the kern.devstat.all sysctl variable consists of the current devstat
  244  * generation number, and then an array of devstat structures, one for each
  245  * device in the system.
  246  *
  247  * I'm really not too fond of this method of doing things, but there really
  248  * aren't that many alternatives.  We must have some method of making sure
  249  * that the generation number the user gets corresponds with the data the
  250  * user gets.  If the user makes a separate sysctl call to get the
  251  * generation, and then a sysctl call to get the device statistics, the
  252  * device list could have changed in that brief period of time.  By
  253  * supplying the generation number along with the statistics output, we can
  254  * guarantee that the generation number and the statistics match up.
  255  */
  256 static int
  257 sysctl_devstat SYSCTL_HANDLER_ARGS
  258 {
  259         int error, i;
  260         struct devstat *nds;
  261         struct devstatlist *devstat_head;
  262 
  263         if (devstat_num_devs == 0)
  264                 return(EINVAL);
  265 
  266         error = 0;
  267         devstat_head = &device_statq;
  268 
  269         /*
  270          * First push out the generation number.
  271          */
  272         error = SYSCTL_OUT(req, &devstat_generation, sizeof(long));
  273 
  274         /*
  275          * Now push out all the devices.
  276          */
  277         for (i = 0, nds = devstat_head->stqh_first; 
  278             (nds != NULL) && (i < devstat_num_devs) && (error == 0); 
  279              nds = nds->dev_links.stqe_next, i++)
  280                 error = SYSCTL_OUT(req, nds, sizeof(struct devstat));
  281 
  282         return(error);
  283 }
  284 
  285 /*
  286  * Sysctl entries for devstat.  The first one is a node that all the rest
  287  * hang off of. 
  288  */
  289 SYSCTL_NODE(_kern, OID_AUTO, devstat, CTLFLAG_RD, 0, "Device Statistics");
  290 
  291 SYSCTL_PROC(_kern_devstat, OID_AUTO, all, CTLFLAG_RD|CTLTYPE_OPAQUE,
  292             0, 0, sysctl_devstat, "S,devstat", "All Devices");
  293 /*
  294  * Export the number of devices in the system so that userland utilities
  295  * can determine how much memory to allocate to hold all the devices.
  296  */
  297 SYSCTL_INT(_kern_devstat, OID_AUTO, numdevs, CTLFLAG_RD, &devstat_num_devs,
  298           0, "Number of devices in the devstat list");
  299 SYSCTL_LONG(_kern_devstat, OID_AUTO, generation, CTLFLAG_RD,
  300             &devstat_generation, "Devstat list generation");
  301 SYSCTL_INT(_kern_devstat, OID_AUTO, version, CTLFLAG_RD, &devstat_version,
  302           0, "Devstat list version number");
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FreeBSD/Linux Kernel Cross Reference sys/kern/subr_devstat.c

FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_devstat.c
