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 #include <linux/nmi.h>
  20
  21 #include <linux/uaccess.h>
  22
  23 #include "tick-internal.h"
  24
  25 struct timer_list_iter {
  26         int cpu;
  27         bool second_pass;
  28         u64 now;
  29 };
  30
  31 /*
  32  * This allows printing both to /proc/timer_list and
  33  * to the console (on SysRq-Q):
  34  */
  35 __printf(2, 3)
  36 static void SEQ_printf(struct seq_file *m, const char *fmt, ...)
  37 {
  38         va_list args;
  39
  40         va_start(args, fmt);
  41
  42         if (m)
  43                 seq_vprintf(m, fmt, args);
  44         else
  45                 vprintk(fmt, args);
  46
  47         va_end(args);
  48 }
  49
  50 static void print_name_offset(struct seq_file *m, void *sym)
  51 {
  52         char symname[KSYM_NAME_LEN];
  53
  54         if (lookup_symbol_name((unsigned long)sym, symname) < 0)
  55                 SEQ_printf(m, "<%pK>", sym);
  56         else
  57                 SEQ_printf(m, "%s", symname);
  58 }
  59
  60 static void
  61 print_timer(struct seq_file *m, struct hrtimer *taddr, struct hrtimer *timer,
  62             int idx, u64 now)
  63 {
  64         SEQ_printf(m, " #%d: ", idx);
  65         print_name_offset(m, taddr);
  66         SEQ_printf(m, ", ");
  67         print_name_offset(m, timer->function);
  68         SEQ_printf(m, ", S:%02x", timer->state);
  69         SEQ_printf(m, "\n");
  70         SEQ_printf(m, " # expires at %Lu-%Lu nsecs [in %Ld to %Ld nsecs]\n",
  71                 (unsigned long long)ktime_to_ns(hrtimer_get_softexpires(timer)),
  72                 (unsigned long long)ktime_to_ns(hrtimer_get_expires(timer)),
  73                 (long long)(ktime_to_ns(hrtimer_get_softexpires(timer)) - now),
  74                 (long long)(ktime_to_ns(hrtimer_get_expires(timer)) - now));
  75 }
  76
  77 static void
  78 print_active_timers(struct seq_file *m, struct hrtimer_clock_base *base,
  79                     u64 now)
  80 {
  81         struct hrtimer *timer, tmp;
  82         unsigned long next = 0, i;
  83         struct timerqueue_node *curr;
  84         unsigned long flags;
  85
  86 next_one:
  87         i = 0;
  88
  89         touch_nmi_watchdog();
  90
  91         raw_spin_lock_irqsave(&base->cpu_base->lock, flags);
  92
  93         curr = timerqueue_getnext(&base->active);
  94         /*
  95          * Crude but we have to do this O(N*N) thing, because
  96          * we have to unlock the base when printing:
  97          */
  98         while (curr && i < next) {
  99                 curr = timerqueue_iterate_next(curr);
 100                 i++;
 101         }
 102
 103         if (curr) {
 104
 105                 timer = container_of(curr, struct hrtimer, node);
 106                 tmp = *timer;
 107                 raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags);
 108
 109                 print_timer(m, timer, &tmp, i, now);
 110                 next++;
 111                 goto next_one;
 112         }
 113         raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags);
 114 }
 115
 116 static void
 117 print_base(struct seq_file *m, struct hrtimer_clock_base *base, u64 now)
 118 {
 119         SEQ_printf(m, "  .base:       %pK\n", base);
 120         SEQ_printf(m, "  .index:      %d\n", base->index);
 121
 122         SEQ_printf(m, "  .resolution: %u nsecs\n", hrtimer_resolution);
 123
 124         SEQ_printf(m,   "  .get_time:   ");
 125         print_name_offset(m, base->get_time);
 126         SEQ_printf(m,   "\n");
 127 #ifdef CONFIG_HIGH_RES_TIMERS
 128         SEQ_printf(m, "  .offset:     %Lu nsecs\n",
 129                    (unsigned long long) ktime_to_ns(base->offset));
 130 #endif
 131         SEQ_printf(m,   "active timers:\n");
 132         print_active_timers(m, base, now + ktime_to_ns(base->offset));
 133 }
 134
 135 static void print_cpu(struct seq_file *m, int cpu, u64 now)
 136 {
 137         struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
 138         int i;
 139
 140         SEQ_printf(m, "cpu: %d\n", cpu);
 141         for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
 142                 SEQ_printf(m, " clock %d:\n", i);
 143                 print_base(m, cpu_base->clock_base + i, now);
 144         }
 145 #define P(x) \
 146         SEQ_printf(m, "  .%-15s: %Lu\n", #x, \
 147                    (unsigned long long)(cpu_base->x))
 148 #define P_ns(x) \
 149         SEQ_printf(m, "  .%-15s: %Lu nsecs\n", #x, \
 150                    (unsigned long long)(ktime_to_ns(cpu_base->x)))
 151
 152 #ifdef CONFIG_HIGH_RES_TIMERS
 153         P_ns(expires_next);
 154         P(hres_active);
 155         P(nr_events);
 156         P(nr_retries);
 157         P(nr_hangs);
 158         P(max_hang_time);
 159 #endif
 160 #undef P
 161 #undef P_ns
 162
 163 #ifdef CONFIG_TICK_ONESHOT
 164 # define P(x) \
 165         SEQ_printf(m, "  .%-15s: %Lu\n", #x, \
 166                    (unsigned long long)(ts->x))
 167 # define P_ns(x) \
 168         SEQ_printf(m, "  .%-15s: %Lu nsecs\n", #x, \
 169                    (unsigned long long)(ktime_to_ns(ts->x)))
 170         {
 171                 struct tick_sched *ts = tick_get_tick_sched(cpu);
 172                 P(nohz_mode);
 173                 P_ns(last_tick);
 174                 P(tick_stopped);
 175                 P(idle_jiffies);
 176                 P(idle_calls);
 177                 P(idle_sleeps);
 178                 P_ns(idle_entrytime);
 179                 P_ns(idle_waketime);
 180                 P_ns(idle_exittime);
 181                 P_ns(idle_sleeptime);
 182                 P_ns(iowait_sleeptime);
 183                 P(last_jiffies);
 184                 P(next_timer);
 185                 P_ns(idle_expires);
 186                 SEQ_printf(m, "jiffies: %Lu\n",
 187                            (unsigned long long)jiffies);
 188         }
 189 #endif
 190
 191 #undef P
 192 #undef P_ns
 193         SEQ_printf(m, "\n");
 194 }
 195
 196 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 197 static void
 198 print_tickdevice(struct seq_file *m, struct tick_device *td, int cpu)
 199 {
 200         struct clock_event_device *dev = td->evtdev;
 201
 202         touch_nmi_watchdog();
 203
 204         SEQ_printf(m, "Tick Device: mode:     %d\n", td->mode);
 205         if (cpu < 0)
 206                 SEQ_printf(m, "Broadcast device\n");
 207         else
 208                 SEQ_printf(m, "Per CPU device: %d\n", cpu);
 209
 210         SEQ_printf(m, "Clock Event Device: ");
 211         if (!dev) {
 212                 SEQ_printf(m, "<NULL>\n");
 213                 return;
 214         }
 215         SEQ_printf(m, "%s\n", dev->name);
 216         SEQ_printf(m, " max_delta_ns:   %llu\n",
 217                    (unsigned long long) dev->max_delta_ns);
 218         SEQ_printf(m, " min_delta_ns:   %llu\n",
 219                    (unsigned long long) dev->min_delta_ns);
 220         SEQ_printf(m, " mult:           %u\n", dev->mult);
 221         SEQ_printf(m, " shift:          %u\n", dev->shift);
 222         SEQ_printf(m, " mode:           %d\n", clockevent_get_state(dev));
 223         SEQ_printf(m, " next_event:     %Ld nsecs\n",
 224                    (unsigned long long) ktime_to_ns(dev->next_event));
 225
 226         SEQ_printf(m, " set_next_event: ");
 227         print_name_offset(m, dev->set_next_event);
 228         SEQ_printf(m, "\n");
 229
 230         if (dev->set_state_shutdown) {
 231                 SEQ_printf(m, " shutdown: ");
 232                 print_name_offset(m, dev->set_state_shutdown);
 233                 SEQ_printf(m, "\n");
 234         }
 235
 236         if (dev->set_state_periodic) {
 237                 SEQ_printf(m, " periodic: ");
 238                 print_name_offset(m, dev->set_state_periodic);
 239                 SEQ_printf(m, "\n");
 240         }
 241
 242         if (dev->set_state_oneshot) {
 243                 SEQ_printf(m, " oneshot:  ");
 244                 print_name_offset(m, dev->set_state_oneshot);
 245                 SEQ_printf(m, "\n");
 246         }
 247
 248         if (dev->set_state_oneshot_stopped) {
 249                 SEQ_printf(m, " oneshot stopped: ");
 250                 print_name_offset(m, dev->set_state_oneshot_stopped);
 251                 SEQ_printf(m, "\n");
 252         }
 253
 254         if (dev->tick_resume) {
 255                 SEQ_printf(m, " resume:   ");
 256                 print_name_offset(m, dev->tick_resume);
 257                 SEQ_printf(m, "\n");
 258         }
 259
 260         SEQ_printf(m, " event_handler:  ");
 261         print_name_offset(m, dev->event_handler);
 262         SEQ_printf(m, "\n");
 263         SEQ_printf(m, " retries:        %lu\n", dev->retries);
 264         SEQ_printf(m, "\n");
 265 }
 266
 267 static void timer_list_show_tickdevices_header(struct seq_file *m)
 268 {
 269 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 270         print_tickdevice(m, tick_get_broadcast_device(), -1);
 271         SEQ_printf(m, "tick_broadcast_mask: %*pb\n",
 272                    cpumask_pr_args(tick_get_broadcast_mask()));
 273 #ifdef CONFIG_TICK_ONESHOT
 274         SEQ_printf(m, "tick_broadcast_oneshot_mask: %*pb\n",
 275                    cpumask_pr_args(tick_get_broadcast_oneshot_mask()));
 276 #endif
 277         SEQ_printf(m, "\n");
 278 #endif
 279 }
 280 #endif
 281
 282 static inline void timer_list_header(struct seq_file *m, u64 now)
 283 {
 284         SEQ_printf(m, "Timer List Version: v0.8\n");
 285         SEQ_printf(m, "HRTIMER_MAX_CLOCK_BASES: %d\n", HRTIMER_MAX_CLOCK_BASES);
 286         SEQ_printf(m, "now at %Ld nsecs\n", (unsigned long long)now);
 287         SEQ_printf(m, "\n");
 288 }
 289
 290 void sysrq_timer_list_show(void)
 291 {
 292         u64 now = ktime_to_ns(ktime_get());
 293         int cpu;
 294
 295         timer_list_header(NULL, now);
 296
 297         for_each_online_cpu(cpu)
 298                 print_cpu(NULL, cpu, now);
 299
 300 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 301         timer_list_show_tickdevices_header(NULL);
 302         for_each_online_cpu(cpu)
 303                 print_tickdevice(NULL, tick_get_device(cpu), cpu);
 304 #endif
 305         return;
 306 }
 307
 308 #ifdef CONFIG_PROC_FS
 309 static int timer_list_show(struct seq_file *m, void *v)
 310 {
 311         struct timer_list_iter *iter = v;
 312
 313         if (iter->cpu == -1 && !iter->second_pass)
 314                 timer_list_header(m, iter->now);
 315         else if (!iter->second_pass)
 316                 print_cpu(m, iter->cpu, iter->now);
 317 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 318         else if (iter->cpu == -1 && iter->second_pass)
 319                 timer_list_show_tickdevices_header(m);
 320         else
 321                 print_tickdevice(m, tick_get_device(iter->cpu), iter->cpu);
 322 #endif
 323         return 0;
 324 }
 325
 326 static void *move_iter(struct timer_list_iter *iter, loff_t offset)
 327 {
 328         for (; offset; offset--) {
 329                 iter->cpu = cpumask_next(iter->cpu, cpu_online_mask);
 330                 if (iter->cpu >= nr_cpu_ids) {
 331 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 332                         if (!iter->second_pass) {
 333                                 iter->cpu = -1;
 334                                 iter->second_pass = true;
 335                         } else
 336                                 return NULL;
 337 #else
 338                         return NULL;
 339 #endif
 340                 }
 341         }
 342         return iter;
 343 }
 344
 345 static void *timer_list_start(struct seq_file *file, loff_t *offset)
 346 {
 347         struct timer_list_iter *iter = file->private;
 348
 349         if (!*offset)
 350                 iter->now = ktime_to_ns(ktime_get());
 351         iter->cpu = -1;
 352         iter->second_pass = false;
 353         return move_iter(iter, *offset);
 354 }
 355
 356 static void *timer_list_next(struct seq_file *file, void *v, loff_t *offset)
 357 {
 358         struct timer_list_iter *iter = file->private;
 359         ++*offset;
 360         return move_iter(iter, 1);
 361 }
 362
 363 static void timer_list_stop(struct seq_file *seq, void *v)
 364 {
 365 }
 366
 367 static const struct seq_operations timer_list_sops = {
 368         .start = timer_list_start,
 369         .next = timer_list_next,
 370         .stop = timer_list_stop,
 371         .show = timer_list_show,
 372 };
 373
 374 static int __init init_timer_list_procfs(void)
 375 {
 376         struct proc_dir_entry *pe;
 377
 378         pe = proc_create_seq_private("timer_list", 0400, NULL, &timer_list_sops,
 379                         sizeof(struct timer_list_iter), NULL);
 380         if (!pe)
 381                 return -ENOMEM;
 382         return 0;
 383 }
 384 __initcall(init_timer_list_procfs);
 385 #endif