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 typedef void (*print_fn_t)(struct seq_file *m, unsigned int *classes);
  32
  33 /*
  34  * This allows printing both to /proc/timer_list and
  35  * to the console (on SysRq-Q):
  36  */
  37 __printf(2, 3)
  38 static void SEQ_printf(struct seq_file *m, const char *fmt, ...)
  39 {
  40         va_list args;
  41
  42         va_start(args, fmt);
  43
  44         if (m)
  45                 seq_vprintf(m, fmt, args);
  46         else
  47                 vprintk(fmt, args);
  48
  49         va_end(args);
  50 }
  51
  52 static void print_name_offset(struct seq_file *m, void *sym)
  53 {
  54         char symname[KSYM_NAME_LEN];
  55
  56         if (lookup_symbol_name((unsigned long)sym, symname) < 0)
  57                 SEQ_printf(m, "<%pK>", sym);
  58         else
  59                 SEQ_printf(m, "%s", symname);
  60 }
  61
  62 static void
  63 print_timer(struct seq_file *m, struct hrtimer *taddr, struct hrtimer *timer,
  64             int idx, u64 now)
  65 {
  66         SEQ_printf(m, " #%d: ", idx);
  67         print_name_offset(m, taddr);
  68         SEQ_printf(m, ", ");
  69         print_name_offset(m, timer->function);
  70         SEQ_printf(m, ", S:%02x", timer->state);
  71         SEQ_printf(m, "\n");
  72         SEQ_printf(m, " # expires at %Lu-%Lu nsecs [in %Ld to %Ld nsecs]\n",
  73                 (unsigned long long)ktime_to_ns(hrtimer_get_softexpires(timer)),
  74                 (unsigned long long)ktime_to_ns(hrtimer_get_expires(timer)),
  75                 (long long)(ktime_to_ns(hrtimer_get_softexpires(timer)) - now),
  76                 (long long)(ktime_to_ns(hrtimer_get_expires(timer)) - now));
  77 }
  78
  79 static void
  80 print_active_timers(struct seq_file *m, struct hrtimer_clock_base *base,
  81                     u64 now)
  82 {
  83         struct hrtimer *timer, tmp;
  84         unsigned long next = 0, i;
  85         struct timerqueue_node *curr;
  86         unsigned long flags;
  87
  88 next_one:
  89         i = 0;
  90
  91         touch_nmi_watchdog();
  92
  93         raw_spin_lock_irqsave(&base->cpu_base->lock, flags);
  94
  95         curr = timerqueue_getnext(&base->active);
  96         /*
  97          * Crude but we have to do this O(N*N) thing, because
  98          * we have to unlock the base when printing:
  99          */
 100         while (curr && i < next) {
 101                 curr = timerqueue_iterate_next(curr);
 102                 i++;
 103         }
 104
 105         if (curr) {
 106
 107                 timer = container_of(curr, struct hrtimer, node);
 108                 tmp = *timer;
 109                 raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags);
 110
 111                 print_timer(m, timer, &tmp, i, now);
 112                 next++;
 113                 goto next_one;
 114         }
 115         raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags);
 116 }
 117
 118 static void
 119 print_base(struct seq_file *m, struct hrtimer_clock_base *base, u64 now)
 120 {
 121         SEQ_printf(m, "  .base:       %pK\n", base);
 122         SEQ_printf(m, "  .index:      %d\n", base->index);
 123
 124         SEQ_printf(m, "  .resolution: %u nsecs\n", hrtimer_resolution);
 125
 126         SEQ_printf(m,   "  .get_time:   ");
 127         print_name_offset(m, base->get_time);
 128         SEQ_printf(m,   "\n");
 129 #ifdef CONFIG_HIGH_RES_TIMERS
 130         SEQ_printf(m, "  .offset:     %Lu nsecs\n",
 131                    (unsigned long long) ktime_to_ns(base->offset));
 132 #endif
 133         SEQ_printf(m,   "active timers:\n");
 134         print_active_timers(m, base, now + ktime_to_ns(base->offset));
 135 }
 136
 137 static void print_cpu(struct seq_file *m, int cpu, u64 now)
 138 {
 139         struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
 140         int i;
 141
 142         SEQ_printf(m, "cpu: %d\n", cpu);
 143         for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
 144                 SEQ_printf(m, " clock %d:\n", i);
 145                 print_base(m, cpu_base->clock_base + i, now);
 146         }
 147 #define P(x) \
 148         SEQ_printf(m, "  .%-15s: %Lu\n", #x, \
 149                    (unsigned long long)(cpu_base->x))
 150 #define P_ns(x) \
 151         SEQ_printf(m, "  .%-15s: %Lu nsecs\n", #x, \
 152                    (unsigned long long)(ktime_to_ns(cpu_base->x)))
 153
 154 #ifdef CONFIG_HIGH_RES_TIMERS
 155         P_ns(expires_next);
 156         P(hres_active);
 157         P(nr_events);
 158         P(nr_retries);
 159         P(nr_hangs);
 160         P(max_hang_time);
 161 #endif
 162 #undef P
 163 #undef P_ns
 164
 165 #ifdef CONFIG_TICK_ONESHOT
 166 # define P(x) \
 167         SEQ_printf(m, "  .%-15s: %Lu\n", #x, \
 168                    (unsigned long long)(ts->x))
 169 # define P_ns(x) \
 170         SEQ_printf(m, "  .%-15s: %Lu nsecs\n", #x, \
 171                    (unsigned long long)(ktime_to_ns(ts->x)))
 172         {
 173                 struct tick_sched *ts = tick_get_tick_sched(cpu);
 174                 P(nohz_mode);
 175                 P_ns(last_tick);
 176                 P(tick_stopped);
 177                 P(idle_jiffies);
 178                 P(idle_calls);
 179                 P(idle_sleeps);
 180                 P_ns(idle_entrytime);
 181                 P_ns(idle_waketime);
 182                 P_ns(idle_exittime);
 183                 P_ns(idle_sleeptime);
 184                 P_ns(iowait_sleeptime);
 185                 P(last_jiffies);
 186                 P(next_timer);
 187                 P_ns(idle_expires);
 188                 SEQ_printf(m, "jiffies: %Lu\n",
 189                            (unsigned long long)jiffies);
 190         }
 191 #endif
 192
 193 #undef P
 194 #undef P_ns
 195         SEQ_printf(m, "\n");
 196 }
 197
 198 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 199 static void
 200 print_tickdevice(struct seq_file *m, struct tick_device *td, int cpu)
 201 {
 202         struct clock_event_device *dev = td->evtdev;
 203
 204         touch_nmi_watchdog();
 205
 206         SEQ_printf(m, "Tick Device: mode:     %d\n", td->mode);
 207         if (cpu < 0)
 208                 SEQ_printf(m, "Broadcast device\n");
 209         else
 210                 SEQ_printf(m, "Per CPU device: %d\n", cpu);
 211
 212         SEQ_printf(m, "Clock Event Device: ");
 213         if (!dev) {
 214                 SEQ_printf(m, "<NULL>\n");
 215                 return;
 216         }
 217         SEQ_printf(m, "%s\n", dev->name);
 218         SEQ_printf(m, " max_delta_ns:   %llu\n",
 219                    (unsigned long long) dev->max_delta_ns);
 220         SEQ_printf(m, " min_delta_ns:   %llu\n",
 221                    (unsigned long long) dev->min_delta_ns);
 222         SEQ_printf(m, " mult:           %u\n", dev->mult);
 223         SEQ_printf(m, " shift:          %u\n", dev->shift);
 224         SEQ_printf(m, " mode:           %d\n", clockevent_get_state(dev));
 225         SEQ_printf(m, " next_event:     %Ld nsecs\n",
 226                    (unsigned long long) ktime_to_ns(dev->next_event));
 227
 228         SEQ_printf(m, " set_next_event: ");
 229         print_name_offset(m, dev->set_next_event);
 230         SEQ_printf(m, "\n");
 231
 232         if (dev->set_state_shutdown) {
 233                 SEQ_printf(m, " shutdown: ");
 234                 print_name_offset(m, dev->set_state_shutdown);
 235                 SEQ_printf(m, "\n");
 236         }
 237
 238         if (dev->set_state_periodic) {
 239                 SEQ_printf(m, " periodic: ");
 240                 print_name_offset(m, dev->set_state_periodic);
 241                 SEQ_printf(m, "\n");
 242         }
 243
 244         if (dev->set_state_oneshot) {
 245                 SEQ_printf(m, " oneshot:  ");
 246                 print_name_offset(m, dev->set_state_oneshot);
 247                 SEQ_printf(m, "\n");
 248         }
 249
 250         if (dev->set_state_oneshot_stopped) {
 251                 SEQ_printf(m, " oneshot stopped: ");
 252                 print_name_offset(m, dev->set_state_oneshot_stopped);
 253                 SEQ_printf(m, "\n");
 254         }
 255
 256         if (dev->tick_resume) {
 257                 SEQ_printf(m, " resume:   ");
 258                 print_name_offset(m, dev->tick_resume);
 259                 SEQ_printf(m, "\n");
 260         }
 261
 262         SEQ_printf(m, " event_handler:  ");
 263         print_name_offset(m, dev->event_handler);
 264         SEQ_printf(m, "\n");
 265         SEQ_printf(m, " retries:        %lu\n", dev->retries);
 266         SEQ_printf(m, "\n");
 267 }
 268
 269 static void timer_list_show_tickdevices_header(struct seq_file *m)
 270 {
 271 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 272         print_tickdevice(m, tick_get_broadcast_device(), -1);
 273         SEQ_printf(m, "tick_broadcast_mask: %*pb\n",
 274                    cpumask_pr_args(tick_get_broadcast_mask()));
 275 #ifdef CONFIG_TICK_ONESHOT
 276         SEQ_printf(m, "tick_broadcast_oneshot_mask: %*pb\n",
 277                    cpumask_pr_args(tick_get_broadcast_oneshot_mask()));
 278 #endif
 279         SEQ_printf(m, "\n");
 280 #endif
 281 }
 282 #endif
 283
 284 static inline void timer_list_header(struct seq_file *m, u64 now)
 285 {
 286         SEQ_printf(m, "Timer List Version: v0.8\n");
 287         SEQ_printf(m, "HRTIMER_MAX_CLOCK_BASES: %d\n", HRTIMER_MAX_CLOCK_BASES);
 288         SEQ_printf(m, "now at %Ld nsecs\n", (unsigned long long)now);
 289         SEQ_printf(m, "\n");
 290 }
 291
 292 void sysrq_timer_list_show(void)
 293 {
 294         u64 now = ktime_to_ns(ktime_get());
 295         int cpu;
 296
 297         timer_list_header(NULL, now);
 298
 299         for_each_online_cpu(cpu)
 300                 print_cpu(NULL, cpu, now);
 301
 302 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 303         timer_list_show_tickdevices_header(NULL);
 304         for_each_online_cpu(cpu)
 305                 print_tickdevice(NULL, tick_get_device(cpu), cpu);
 306 #endif
 307         return;
 308 }
 309
 310 #ifdef CONFIG_PROC_FS
 311 static int timer_list_show(struct seq_file *m, void *v)
 312 {
 313         struct timer_list_iter *iter = v;
 314
 315         if (iter->cpu == -1 && !iter->second_pass)
 316                 timer_list_header(m, iter->now);
 317         else if (!iter->second_pass)
 318                 print_cpu(m, iter->cpu, iter->now);
 319 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 320         else if (iter->cpu == -1 && iter->second_pass)
 321                 timer_list_show_tickdevices_header(m);
 322         else
 323                 print_tickdevice(m, tick_get_device(iter->cpu), iter->cpu);
 324 #endif
 325         return 0;
 326 }
 327
 328 static void *move_iter(struct timer_list_iter *iter, loff_t offset)
 329 {
 330         for (; offset; offset--) {
 331                 iter->cpu = cpumask_next(iter->cpu, cpu_online_mask);
 332                 if (iter->cpu >= nr_cpu_ids) {
 333 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 334                         if (!iter->second_pass) {
 335                                 iter->cpu = -1;
 336                                 iter->second_pass = true;
 337                         } else
 338                                 return NULL;
 339 #else
 340                         return NULL;
 341 #endif
 342                 }
 343         }
 344         return iter;
 345 }
 346
 347 static void *timer_list_start(struct seq_file *file, loff_t *offset)
 348 {
 349         struct timer_list_iter *iter = file->private;
 350
 351         if (!*offset)
 352                 iter->now = ktime_to_ns(ktime_get());
 353         iter->cpu = -1;
 354         iter->second_pass = false;
 355         return move_iter(iter, *offset);
 356 }
 357
 358 static void *timer_list_next(struct seq_file *file, void *v, loff_t *offset)
 359 {
 360         struct timer_list_iter *iter = file->private;
 361         ++*offset;
 362         return move_iter(iter, 1);
 363 }
 364
 365 static void timer_list_stop(struct seq_file *seq, void *v)
 366 {
 367 }
 368
 369 static const struct seq_operations timer_list_sops = {
 370         .start = timer_list_start,
 371         .next = timer_list_next,
 372         .stop = timer_list_stop,
 373         .show = timer_list_show,
 374 };
 375
 376 static int timer_list_open(struct inode *inode, struct file *filp)
 377 {
 378         return seq_open_private(filp, &timer_list_sops,
 379                         sizeof(struct timer_list_iter));
 380 }
 381
 382 static const struct file_operations timer_list_fops = {
 383         .open           = timer_list_open,
 384         .read           = seq_read,
 385         .llseek         = seq_lseek,
 386         .release        = seq_release_private,
 387 };
 388
 389 static int __init init_timer_list_procfs(void)
 390 {
 391         struct proc_dir_entry *pe;
 392
 393         pe = proc_create("timer_list", 0400, NULL, &timer_list_fops);
 394         if (!pe)
 395                 return -ENOMEM;
 396         return 0;
 397 }
 398 __initcall(init_timer_list_procfs);
 399 #endif