sys/kern/kern_collect.c

   1 /*
   2  * Copyright (c) 2017 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  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  21  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  22  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  23  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  24  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  25  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  26  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  27  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  28  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 /*
  33  * Collects general statistics on a 10-second interval.
  34  */
  35
  36 #include <sys/param.h>
  37 #include <sys/systm.h>
  38 #include <sys/kernel.h>
  39 #include <sys/proc.h>
  40 #include <sys/kinfo.h>
  41 #include <sys/queue.h>
  42 #include <sys/sysctl.h>
  43 #include <sys/kthread.h>
  44 #include <machine/cpu.h>
  45 #include <sys/lock.h>
  46 #include <sys/spinlock.h>
  47 #include <sys/kcollect.h>
  48 #include <sys/malloc.h>
  49
  50 #include <sys/thread2.h>
  51 #include <sys/spinlock2.h>
  52
  53 #include <vm/vm.h>
  54 #include <vm/vm_param.h>
  55 #include <vm/vm_kern.h>
  56 #include <vm/vm_object.h>
  57 #include <vm/vm_page.h>
  58 #include <vm/vm_map.h>
  59 #include <vm/vm_pager.h>
  60 #include <vm/vm_extern.h>
  61
  62 #include <machine/stdarg.h>
  63 #include <machine/smp.h>
  64 #include <machine/clock.h>
  65
  66 static uint32_t kcollect_samples = -1;  /* 0 to disable */
  67 TUNABLE_INT("kern.collect_samples", &kcollect_samples);
  68 SYSCTL_UINT(_kern, OID_AUTO, collect_samples, CTLFLAG_RD,
  69         &kcollect_samples, 0, "number of 10-second samples");
  70
  71 static uint64_t kcollect_index;
  72 static const char *kcollect_slots[KCOLLECT_ENTRIES];
  73 static kcallback_t kcollect_callback[KCOLLECT_ENTRIES];
  74 static kcollect_t kcollect_scale;
  75 static kcollect_t *kcollect_ary;
  76 static struct lock kcollect_lock = LOCK_INITIALIZER("kcolk", 0, 0);
  77
  78 MALLOC_DEFINE(M_KCOLLECT, "kcollect", "kcollect array");
  79
  80 int
  81 kcollect_register(int which, const char *id, kcallback_t func, uint64_t scale)
  82 {
  83         int n;
  84
  85         lockmgr(&kcollect_lock, LK_EXCLUSIVE);
  86         if (which >= 0) {
  87                 n = which;
  88         } else {
  89                 for (n = KCOLLECT_DYNAMIC_START; n < KCOLLECT_ENTRIES; ++n) {
  90                         if (kcollect_slots[n] == NULL)
  91                                 break;
  92                 }
  93         }
  94         if (n < 0 || n >= KCOLLECT_ENTRIES) {
  95                 n = -1;
  96         } else {
  97                 kcollect_slots[n] = id;
  98                 kcollect_callback[n] = func;
  99                 kcollect_scale.data[n] = scale;
 100         }
 101         lockmgr(&kcollect_lock, LK_RELEASE);
 102
 103         return n;
 104 }
 105
 106 void
 107 kcollect_unregister(int n)
 108 {
 109         lockmgr(&kcollect_lock, LK_EXCLUSIVE);
 110         if (n >= 0 && n < KCOLLECT_ENTRIES) {
 111                 kcollect_slots[n] = NULL;
 112                 kcollect_callback[n] = NULL;
 113         }
 114         lockmgr(&kcollect_lock, LK_RELEASE);
 115 }
 116
 117 /*
 118  * Typically called by a rollup function in the callback from the
 119  * collection thread.  Not usually called ad-hoc.  This allows a
 120  * subsystem to register several collection ids but only one callback
 121  * which populates all of them.
 122  */
 123 void
 124 kcollect_setvalue(int n, uint64_t value)
 125 {
 126         uint32_t i;
 127
 128         if (n >= 0 && n < KCOLLECT_ENTRIES) {
 129                 i = kcollect_index % kcollect_samples;
 130                 kcollect_ary[i].data[n] = value;
 131         }
 132 }
 133
 134 /*
 135  * Callback to change scale adjustment, if necessary.  Certain statistics
 136  * have scale info available (such as KCOLLECT_SWAPANO and SWAPCAC).
 137  */
 138 void
 139 kcollect_setscale(int n, uint64_t value)
 140 {
 141         if (n >= 0 && n < KCOLLECT_ENTRIES) {
 142                 kcollect_scale.data[n] = value;
 143         }
 144 }
 145
 146 static
 147 void
 148 kcollect_thread(void *dummy)
 149 {
 150         uint32_t i;
 151         int n;
 152
 153         for (;;) {
 154                 lockmgr(&kcollect_lock, LK_EXCLUSIVE);
 155                 i = kcollect_index % kcollect_samples;
 156                 bzero(&kcollect_ary[i], sizeof(kcollect_ary[i]));
 157                 crit_enter();
 158                 kcollect_ary[i].ticks = ticks;
 159                 getmicrotime(&kcollect_ary[i].realtime);
 160                 crit_exit();
 161                 for (n = 0; n < KCOLLECT_ENTRIES; ++n) {
 162                         if (kcollect_callback[n]) {
 163                                 kcollect_ary[i].data[n] =
 164                                         kcollect_callback[n](n);
 165                         }
 166                 }
 167                 cpu_sfence();
 168                 ++kcollect_index;
 169                 lockmgr(&kcollect_lock, LK_RELEASE);
 170                 tsleep(&dummy, 0, "sleep", hz * KCOLLECT_INTERVAL);
 171         }
 172 }
 173
 174 /*
 175  * No requirements.
 176  */
 177 static int
 178 sysctl_kcollect_data(SYSCTL_HANDLER_ARGS)
 179 {
 180         int error;
 181         uint32_t i;
 182         uint32_t start;
 183         uint64_t count;
 184         kcollect_t scale;
 185         kcollect_t id;
 186
 187         if (kcollect_samples == (uint32_t)-1 ||
 188             kcollect_samples == 0) {
 189                 return EINVAL;
 190         }
 191
 192         error = 0;
 193         count = kcollect_index;
 194         start = count % kcollect_samples;
 195         if (count >= kcollect_samples)
 196                 count = kcollect_samples - 1;
 197
 198         /*
 199          * Sizing request
 200          */
 201         if (req->oldptr == NULL) {
 202                 error = SYSCTL_OUT(req, 0, sizeof(kcollect_t) * (count + 2));
 203                 return error;
 204         }
 205
 206         /*
 207          * Output request.  We output a scale record, a string record, and
 208          * N collection records.  The strings in the string record can be
 209          * up to 8 characters long, and if a string is 8 characters long it
 210          * will not be zero-terminated.
 211          *
 212          * The low byte of the scale record specifies the format.  To get
 213          * the scale value shift right by 8.
 214          */
 215         if (kcollect_ary == NULL)
 216                 return ENOTSUP;
 217
 218         lockmgr(&kcollect_lock, LK_EXCLUSIVE);
 219         scale = kcollect_scale;
 220         scale.ticks = ticks;
 221         scale.hz = hz;
 222
 223         bzero(&id, sizeof(id));
 224         for (i = 0; i < KCOLLECT_ENTRIES; ++i) {
 225                 if (kcollect_slots[i]) {
 226                         char *ptr = (char *)&id.data[i];
 227                         size_t len = strlen(kcollect_slots[i]);
 228                         if (len > sizeof(id.data[0]))
 229                                 len = sizeof(id.data[0]);
 230                         bcopy(kcollect_slots[i], ptr, len);
 231                 }
 232         }
 233         lockmgr(&kcollect_lock, LK_RELEASE);
 234
 235         error = SYSCTL_OUT(req, &scale, sizeof(scale));
 236         if (error == 0)
 237                 error = SYSCTL_OUT(req, &id, sizeof(id));
 238
 239         /*
 240          * Start at the current entry (not yet populated) and work
 241          * backwards.  This allows callers of the sysctl to acquire
 242          * a lesser amount of data aligned to the most recent side of
 243          * the array.
 244          */
 245         i = start;
 246         while (count) {
 247                 if (req->oldlen - req->oldidx < sizeof(kcollect_t))
 248                         break;
 249                 if (i == 0)
 250                         i = kcollect_samples - 1;
 251                 else
 252                         --i;
 253                 error = SYSCTL_OUT(req, &kcollect_ary[i], sizeof(kcollect_t));
 254                 if (error)
 255                         break;
 256                 --count;
 257         }
 258         return error;
 259 }
 260 SYSCTL_PROC(_kern, OID_AUTO, collect_data,
 261         CTLFLAG_RD | CTLTYPE_STRUCT, 0, 0,
 262         sysctl_kcollect_data, "S,kcollect", "Dump collected statistics");
 263
 264 static
 265 void
 266 kcollect_thread_init(void)
 267 {
 268         thread_t td = NULL;
 269
 270         /*
 271          * Autosize sample retention (10 second interval)
 272          */
 273         if ((int)kcollect_samples < 0) {
 274                 if (kmem_lim_size() < 1024)
 275                         kcollect_samples = 1024;
 276                 else
 277                         kcollect_samples = 8192;
 278         }
 279
 280         if (kcollect_samples) {
 281                 kcollect_ary = kmalloc(kcollect_samples * sizeof(kcollect_t),
 282                                        M_KCOLLECT, M_WAITOK | M_ZERO);
 283                 lwkt_create(kcollect_thread, NULL, &td, NULL, 0, 0, "kcollect");
 284         }
 285 }
 286 SYSINIT(kcol, SI_SUB_HELPER_THREADS, SI_ORDER_ANY, kcollect_thread_init, 0);