kernel/time/timer_list.c

   1 /*
   2  * kernel/time/timer_list.c
   3  *
   4  * List pending timers
   5  *
   6  * Copyright(C) 2006, Red Hat, Inc., Ingo Molnar
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/proc_fs.h>
  14 #include <linux/module.h>
  15 #include <linux/spinlock.h>
  16 #include <linux/sched.h>
  17 #include <linux/seq_file.h>
  18 #include <linux/kallsyms.h>
  19
  20 #include <linux/uaccess.h>
  21
  22 #include "tick-internal.h"
  23
  24 struct timer_list_iter {
  25         int cpu;
  26         bool second_pass;
  27         u64 now;
  28 };
  29
  30 typedef void (*print_fn_t)(struct seq_file *m, unsigned int *classes);
  31
  32 /*
  33  * This allows printing both to /proc/timer_list and
  34  * to the console (on SysRq-Q):
  35  */
  36 __printf(2, 3)
  37 static void SEQ_printf(struct seq_file *m, const char *fmt, ...)
  38 {
  39         va_list args;
  40
  41         va_start(args, fmt);
  42
  43         if (m)
  44                 seq_vprintf(m, fmt, args);
  45         else
  46                 vprintk(fmt, args);
  47
  48         va_end(args);
  49 }
  50
  51 static void print_name_offset(struct seq_file *m, void *sym)
  52 {
  53         char symname[KSYM_NAME_LEN];
  54
  55         if (lookup_symbol_name((unsigned long)sym, symname) < 0)
  56                 SEQ_printf(m, "<%pK>", sym);
  57         else
  58                 SEQ_printf(m, "%s", symname);
  59 }
  60
  61 static void
  62 print_timer(struct seq_file *m, struct hrtimer *taddr, struct hrtimer *timer,
  63             int idx, u64 now)
  64 {
  65         SEQ_printf(m, " #%d: ", idx);
  66         print_name_offset(m, taddr);
  67         SEQ_printf(m, ", ");
  68         print_name_offset(m, timer->function);
  69         SEQ_printf(m, ", S:%02x", timer->state);
  70         SEQ_printf(m, "\n");
  71         SEQ_printf(m, " # expires at %Lu-%Lu nsecs [in %Ld to %Ld nsecs]\n",
  72                 (unsigned long long)ktime_to_ns(hrtimer_get_softexpires(timer)),
  73                 (unsigned long long)ktime_to_ns(hrtimer_get_expires(timer)),
  74                 (long long)(ktime_to_ns(hrtimer_get_softexpires(timer)) - now),
  75                 (long long)(ktime_to_ns(hrtimer_get_expires(timer)) - now));
  76 }
  77
  78 static void
  79 print_active_timers(struct seq_file *m, struct hrtimer_clock_base *base,
  80                     u64 now)
  81 {
  82         struct hrtimer *timer, tmp;
  83         unsigned long next = 0, i;
  84         struct timerqueue_node *curr;
  85         unsigned long flags;
  86
  87 next_one:
  88         i = 0;
  89         raw_spin_lock_irqsave(&base->cpu_base->lock, flags);
  90
  91         curr = timerqueue_getnext(&base->active);
  92         /*
  93          * Crude but we have to do this O(N*N) thing, because
  94          * we have to unlock the base when printing:
  95          */
  96         while (curr && i < next) {
  97                 curr = timerqueue_iterate_next(curr);
  98                 i++;
  99         }
 100
 101         if (curr) {
 102
 103                 timer = container_of(curr, struct hrtimer, node);
 104                 tmp = *timer;
 105                 raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags);
 106
 107                 print_timer(m, timer, &tmp, i, now);
 108                 next++;
 109                 goto next_one;
 110         }
 111         raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags);
 112 }
 113
 114 static void
 115 print_base(struct seq_file *m, struct hrtimer_clock_base *base, u64 now)
 116 {
 117         SEQ_printf(m, "  .base:       %pK\n", base);
 118         SEQ_printf(m, "  .index:      %d\n", base->index);
 119
 120         SEQ_printf(m, "  .resolution: %u nsecs\n", hrtimer_resolution);
 121
 122         SEQ_printf(m,   "  .get_time:   ");
 123         print_name_offset(m, base->get_time);
 124         SEQ_printf(m,   "\n");
 125 #ifdef CONFIG_HIGH_RES_TIMERS
 126         SEQ_printf(m, "  .offset:     %Lu nsecs\n",
 127                    (unsigned long long) ktime_to_ns(base->offset));
 128 #endif
 129         SEQ_printf(m,   "active timers:\n");
 130         print_active_timers(m, base, now + ktime_to_ns(base->offset));
 131 }
 132
 133 static void print_cpu(struct seq_file *m, int cpu, u64 now)
 134 {
 135         struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
 136         int i;
 137
 138         SEQ_printf(m, "cpu: %d\n", cpu);
 139         for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
 140                 SEQ_printf(m, " clock %d:\n", i);
 141                 print_base(m, cpu_base->clock_base + i, now);
 142         }
 143 #define P(x) \
 144         SEQ_printf(m, "  .%-15s: %Lu\n", #x, \
 145                    (unsigned long long)(cpu_base->x))
 146 #define P_ns(x) \
 147         SEQ_printf(m, "  .%-15s: %Lu nsecs\n", #x, \
 148                    (unsigned long long)(ktime_to_ns(cpu_base->x)))
 149
 150 #ifdef CONFIG_HIGH_RES_TIMERS
 151         P_ns(expires_next);
 152         P(hres_active);
 153         P(nr_events);
 154         P(nr_retries);
 155         P(nr_hangs);
 156         P(max_hang_time);
 157 #endif
 158 #undef P
 159 #undef P_ns
 160
 161 #ifdef CONFIG_TICK_ONESHOT
 162 # define P(x) \
 163         SEQ_printf(m, "  .%-15s: %Lu\n", #x, \
 164                    (unsigned long long)(ts->x))
 165 # define P_ns(x) \
 166         SEQ_printf(m, "  .%-15s: %Lu nsecs\n", #x, \
 167                    (unsigned long long)(ktime_to_ns(ts->x)))
 168         {
 169                 struct tick_sched *ts = tick_get_tick_sched(cpu);
 170                 P(nohz_mode);
 171                 P_ns(last_tick);
 172                 P(tick_stopped);
 173                 P(idle_jiffies);
 174                 P(idle_calls);
 175                 P(idle_sleeps);
 176                 P_ns(idle_entrytime);
 177                 P_ns(idle_waketime);
 178                 P_ns(idle_exittime);
 179                 P_ns(idle_sleeptime);
 180                 P_ns(iowait_sleeptime);
 181                 P(last_jiffies);
 182                 P(next_timer);
 183                 P_ns(idle_expires);
 184                 SEQ_printf(m, "jiffies: %Lu\n",
 185                            (unsigned long long)jiffies);
 186         }
 187 #endif
 188
 189 #undef P
 190 #undef P_ns
 191         SEQ_printf(m, "\n");
 192 }
 193
 194 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 195 static void
 196 print_tickdevice(struct seq_file *m, struct tick_device *td, int cpu)
 197 {
 198         struct clock_event_device *dev = td->evtdev;
 199
 200         SEQ_printf(m, "Tick Device: mode:     %d\n", td->mode);
 201         if (cpu < 0)
 202                 SEQ_printf(m, "Broadcast device\n");
 203         else
 204                 SEQ_printf(m, "Per CPU device: %d\n", cpu);
 205
 206         SEQ_printf(m, "Clock Event Device: ");
 207         if (!dev) {
 208                 SEQ_printf(m, "<NULL>\n");
 209                 return;
 210         }
 211         SEQ_printf(m, "%s\n", dev->name);
 212         SEQ_printf(m, " max_delta_ns:   %llu\n",
 213                    (unsigned long long) dev->max_delta_ns);
 214         SEQ_printf(m, " min_delta_ns:   %llu\n",
 215                    (unsigned long long) dev->min_delta_ns);
 216         SEQ_printf(m, " mult:           %u\n", dev->mult);
 217         SEQ_printf(m, " shift:          %u\n", dev->shift);
 218         SEQ_printf(m, " mode:           %d\n", clockevent_get_state(dev));
 219         SEQ_printf(m, " next_event:     %Ld nsecs\n",
 220                    (unsigned long long) ktime_to_ns(dev->next_event));
 221
 222         SEQ_printf(m, " set_next_event: ");
 223         print_name_offset(m, dev->set_next_event);
 224         SEQ_printf(m, "\n");
 225
 226         if (dev->set_state_shutdown) {
 227                 SEQ_printf(m, " shutdown: ");
 228                 print_name_offset(m, dev->set_state_shutdown);
 229                 SEQ_printf(m, "\n");
 230         }
 231
 232         if (dev->set_state_periodic) {
 233                 SEQ_printf(m, " periodic: ");
 234                 print_name_offset(m, dev->set_state_periodic);
 235                 SEQ_printf(m, "\n");
 236         }
 237
 238         if (dev->set_state_oneshot) {
 239                 SEQ_printf(m, " oneshot:  ");
 240                 print_name_offset(m, dev->set_state_oneshot);
 241                 SEQ_printf(m, "\n");
 242         }
 243
 244         if (dev->set_state_oneshot_stopped) {
 245                 SEQ_printf(m, " oneshot stopped: ");
 246                 print_name_offset(m, dev->set_state_oneshot_stopped);
 247                 SEQ_printf(m, "\n");
 248         }
 249
 250         if (dev->tick_resume) {
 251                 SEQ_printf(m, " resume:   ");
 252                 print_name_offset(m, dev->tick_resume);
 253                 SEQ_printf(m, "\n");
 254         }
 255
 256         SEQ_printf(m, " event_handler:  ");
 257         print_name_offset(m, dev->event_handler);
 258         SEQ_printf(m, "\n");
 259         SEQ_printf(m, " retries:        %lu\n", dev->retries);
 260         SEQ_printf(m, "\n");
 261 }
 262
 263 static void timer_list_show_tickdevices_header(struct seq_file *m)
 264 {
 265 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 266         print_tickdevice(m, tick_get_broadcast_device(), -1);
 267         SEQ_printf(m, "tick_broadcast_mask: %*pb\n",
 268                    cpumask_pr_args(tick_get_broadcast_mask()));
 269 #ifdef CONFIG_TICK_ONESHOT
 270         SEQ_printf(m, "tick_broadcast_oneshot_mask: %*pb\n",
 271                    cpumask_pr_args(tick_get_broadcast_oneshot_mask()));
 272 #endif
 273         SEQ_printf(m, "\n");
 274 #endif
 275 }
 276 #endif
 277
 278 static inline void timer_list_header(struct seq_file *m, u64 now)
 279 {
 280         SEQ_printf(m, "Timer List Version: v0.8\n");
 281         SEQ_printf(m, "HRTIMER_MAX_CLOCK_BASES: %d\n", HRTIMER_MAX_CLOCK_BASES);
 282         SEQ_printf(m, "now at %Ld nsecs\n", (unsigned long long)now);
 283         SEQ_printf(m, "\n");
 284 }
 285
 286 static int timer_list_show(struct seq_file *m, void *v)
 287 {
 288         struct timer_list_iter *iter = v;
 289
 290         if (iter->cpu == -1 && !iter->second_pass)
 291                 timer_list_header(m, iter->now);
 292         else if (!iter->second_pass)
 293                 print_cpu(m, iter->cpu, iter->now);
 294 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 295         else if (iter->cpu == -1 && iter->second_pass)
 296                 timer_list_show_tickdevices_header(m);
 297         else
 298                 print_tickdevice(m, tick_get_device(iter->cpu), iter->cpu);
 299 #endif
 300         return 0;
 301 }
 302
 303 void sysrq_timer_list_show(void)
 304 {
 305         u64 now = ktime_to_ns(ktime_get());
 306         int cpu;
 307
 308         timer_list_header(NULL, now);
 309
 310         for_each_online_cpu(cpu)
 311                 print_cpu(NULL, cpu, now);
 312
 313 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 314         timer_list_show_tickdevices_header(NULL);
 315         for_each_online_cpu(cpu)
 316                 print_tickdevice(NULL, tick_get_device(cpu), cpu);
 317 #endif
 318         return;
 319 }
 320
 321 static void *move_iter(struct timer_list_iter *iter, loff_t offset)
 322 {
 323         for (; offset; offset--) {
 324                 iter->cpu = cpumask_next(iter->cpu, cpu_online_mask);
 325                 if (iter->cpu >= nr_cpu_ids) {
 326 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 327                         if (!iter->second_pass) {
 328                                 iter->cpu = -1;
 329                                 iter->second_pass = true;
 330                         } else
 331                                 return NULL;
 332 #else
 333                         return NULL;
 334 #endif
 335                 }
 336         }
 337         return iter;
 338 }
 339
 340 static void *timer_list_start(struct seq_file *file, loff_t *offset)
 341 {
 342         struct timer_list_iter *iter = file->private;
 343
 344         if (!*offset)
 345                 iter->now = ktime_to_ns(ktime_get());
 346         iter->cpu = -1;
 347         iter->second_pass = false;
 348         return move_iter(iter, *offset);
 349 }
 350
 351 static void *timer_list_next(struct seq_file *file, void *v, loff_t *offset)
 352 {
 353         struct timer_list_iter *iter = file->private;
 354         ++*offset;
 355         return move_iter(iter, 1);
 356 }
 357
 358 static void timer_list_stop(struct seq_file *seq, void *v)
 359 {
 360 }
 361
 362 static const struct seq_operations timer_list_sops = {
 363         .start = timer_list_start,
 364         .next = timer_list_next,
 365         .stop = timer_list_stop,
 366         .show = timer_list_show,
 367 };
 368
 369 static int timer_list_open(struct inode *inode, struct file *filp)
 370 {
 371         return seq_open_private(filp, &timer_list_sops,
 372                         sizeof(struct timer_list_iter));
 373 }
 374
 375 static const struct file_operations timer_list_fops = {
 376         .open           = timer_list_open,
 377         .read           = seq_read,
 378         .llseek         = seq_lseek,
 379         .release        = seq_release_private,
 380 };
 381
 382 static int __init init_timer_list_procfs(void)
 383 {
 384         struct proc_dir_entry *pe;
 385
 386         pe = proc_create("timer_list", 0444, NULL, &timer_list_fops);
 387         if (!pe)
 388                 return -ENOMEM;
 389         return 0;
 390 }
 391 __initcall(init_timer_list_procfs);