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 #ifdef CONFIG_TIMER_STATS
  66         char tmp[TASK_COMM_LEN + 1];
  67 #endif
  68         SEQ_printf(m, " #%d: ", idx);
  69         print_name_offset(m, taddr);
  70         SEQ_printf(m, ", ");
  71         print_name_offset(m, timer->function);
  72         SEQ_printf(m, ", S:%02x", timer->state);
  73 #ifdef CONFIG_TIMER_STATS
  74         SEQ_printf(m, ", ");
  75         print_name_offset(m, timer->start_site);
  76         memcpy(tmp, timer->start_comm, TASK_COMM_LEN);
  77         tmp[TASK_COMM_LEN] = 0;
  78         SEQ_printf(m, ", %s/%d", tmp, timer->start_pid);
  79 #endif
  80         SEQ_printf(m, "\n");
  81         SEQ_printf(m, " # expires at %Lu-%Lu nsecs [in %Ld to %Ld nsecs]\n",
  82                 (unsigned long long)ktime_to_ns(hrtimer_get_softexpires(timer)),
  83                 (unsigned long long)ktime_to_ns(hrtimer_get_expires(timer)),
  84                 (long long)(ktime_to_ns(hrtimer_get_softexpires(timer)) - now),
  85                 (long long)(ktime_to_ns(hrtimer_get_expires(timer)) - now));
  86 }
  87
  88 static void
  89 print_active_timers(struct seq_file *m, struct hrtimer_clock_base *base,
  90                     u64 now)
  91 {
  92         struct hrtimer *timer, tmp;
  93         unsigned long next = 0, i;
  94         struct timerqueue_node *curr;
  95         unsigned long flags;
  96
  97 next_one:
  98         i = 0;
  99         raw_spin_lock_irqsave(&base->cpu_base->lock, flags);
 100
 101         curr = timerqueue_getnext(&base->active);
 102         /*
 103          * Crude but we have to do this O(N*N) thing, because
 104          * we have to unlock the base when printing:
 105          */
 106         while (curr && i < next) {
 107                 curr = timerqueue_iterate_next(curr);
 108                 i++;
 109         }
 110
 111         if (curr) {
 112
 113                 timer = container_of(curr, struct hrtimer, node);
 114                 tmp = *timer;
 115                 raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags);
 116
 117                 print_timer(m, timer, &tmp, i, now);
 118                 next++;
 119                 goto next_one;
 120         }
 121         raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags);
 122 }
 123
 124 static void
 125 print_base(struct seq_file *m, struct hrtimer_clock_base *base, u64 now)
 126 {
 127         SEQ_printf(m, "  .base:       %pK\n", base);
 128         SEQ_printf(m, "  .index:      %d\n", base->index);
 129
 130         SEQ_printf(m, "  .resolution: %u nsecs\n", (unsigned) hrtimer_resolution);
 131
 132         SEQ_printf(m,   "  .get_time:   ");
 133         print_name_offset(m, base->get_time);
 134         SEQ_printf(m,   "\n");
 135 #ifdef CONFIG_HIGH_RES_TIMERS
 136         SEQ_printf(m, "  .offset:     %Lu nsecs\n",
 137                    (unsigned long long) ktime_to_ns(base->offset));
 138 #endif
 139         SEQ_printf(m,   "active timers:\n");
 140         print_active_timers(m, base, now + ktime_to_ns(base->offset));
 141 }
 142
 143 static void print_cpu(struct seq_file *m, int cpu, u64 now)
 144 {
 145         struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
 146         int i;
 147
 148         SEQ_printf(m, "cpu: %d\n", cpu);
 149         for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
 150                 SEQ_printf(m, " clock %d:\n", i);
 151                 print_base(m, cpu_base->clock_base + i, now);
 152         }
 153 #define P(x) \
 154         SEQ_printf(m, "  .%-15s: %Lu\n", #x, \
 155                    (unsigned long long)(cpu_base->x))
 156 #define P_ns(x) \
 157         SEQ_printf(m, "  .%-15s: %Lu nsecs\n", #x, \
 158                    (unsigned long long)(ktime_to_ns(cpu_base->x)))
 159
 160 #ifdef CONFIG_HIGH_RES_TIMERS
 161         P_ns(expires_next);
 162         P(hres_active);
 163         P(nr_events);
 164         P(nr_retries);
 165         P(nr_hangs);
 166         P(max_hang_time);
 167 #endif
 168 #undef P
 169 #undef P_ns
 170
 171 #ifdef CONFIG_TICK_ONESHOT
 172 # define P(x) \
 173         SEQ_printf(m, "  .%-15s: %Lu\n", #x, \
 174                    (unsigned long long)(ts->x))
 175 # define P_ns(x) \
 176         SEQ_printf(m, "  .%-15s: %Lu nsecs\n", #x, \
 177                    (unsigned long long)(ktime_to_ns(ts->x)))
 178         {
 179                 struct tick_sched *ts = tick_get_tick_sched(cpu);
 180                 P(nohz_mode);
 181                 P_ns(last_tick);
 182                 P(tick_stopped);
 183                 P(idle_jiffies);
 184                 P(idle_calls);
 185                 P(idle_sleeps);
 186                 P_ns(idle_entrytime);
 187                 P_ns(idle_waketime);
 188                 P_ns(idle_exittime);
 189                 P_ns(idle_sleeptime);
 190                 P_ns(iowait_sleeptime);
 191                 P(last_jiffies);
 192                 P(next_timer);
 193                 P_ns(idle_expires);
 194                 SEQ_printf(m, "jiffies: %Lu\n",
 195                            (unsigned long long)jiffies);
 196         }
 197 #endif
 198
 199 #undef P
 200 #undef P_ns
 201         SEQ_printf(m, "\n");
 202 }
 203
 204 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 205 static void
 206 print_tickdevice(struct seq_file *m, struct tick_device *td, int cpu)
 207 {
 208         struct clock_event_device *dev = td->evtdev;
 209
 210         SEQ_printf(m, "Tick Device: mode:     %d\n", td->mode);
 211         if (cpu < 0)
 212                 SEQ_printf(m, "Broadcast device\n");
 213         else
 214                 SEQ_printf(m, "Per CPU device: %d\n", cpu);
 215
 216         SEQ_printf(m, "Clock Event Device: ");
 217         if (!dev) {
 218                 SEQ_printf(m, "<NULL>\n");
 219                 return;
 220         }
 221         SEQ_printf(m, "%s\n", dev->name);
 222         SEQ_printf(m, " max_delta_ns:   %llu\n",
 223                    (unsigned long long) dev->max_delta_ns);
 224         SEQ_printf(m, " min_delta_ns:   %llu\n",
 225                    (unsigned long long) dev->min_delta_ns);
 226         SEQ_printf(m, " mult:           %u\n", dev->mult);
 227         SEQ_printf(m, " shift:          %u\n", dev->shift);
 228         SEQ_printf(m, " mode:           %d\n", clockevent_get_state(dev));
 229         SEQ_printf(m, " next_event:     %Ld nsecs\n",
 230                    (unsigned long long) ktime_to_ns(dev->next_event));
 231
 232         SEQ_printf(m, " set_next_event: ");
 233         print_name_offset(m, dev->set_next_event);
 234         SEQ_printf(m, "\n");
 235
 236         if (dev->set_state_shutdown) {
 237                 SEQ_printf(m, " shutdown: ");
 238                 print_name_offset(m, dev->set_state_shutdown);
 239                 SEQ_printf(m, "\n");
 240         }
 241
 242         if (dev->set_state_periodic) {
 243                 SEQ_printf(m, " periodic: ");
 244                 print_name_offset(m, dev->set_state_periodic);
 245                 SEQ_printf(m, "\n");
 246         }
 247
 248         if (dev->set_state_oneshot) {
 249                 SEQ_printf(m, " oneshot:  ");
 250                 print_name_offset(m, dev->set_state_oneshot);
 251                 SEQ_printf(m, "\n");
 252         }
 253
 254         if (dev->set_state_oneshot_stopped) {
 255                 SEQ_printf(m, " oneshot stopped: ");
 256                 print_name_offset(m, dev->set_state_oneshot_stopped);
 257                 SEQ_printf(m, "\n");
 258         }
 259
 260         if (dev->tick_resume) {
 261                 SEQ_printf(m, " resume:   ");
 262                 print_name_offset(m, dev->tick_resume);
 263                 SEQ_printf(m, "\n");
 264         }
 265
 266         SEQ_printf(m, " event_handler:  ");
 267         print_name_offset(m, dev->event_handler);
 268         SEQ_printf(m, "\n");
 269         SEQ_printf(m, " retries:        %lu\n", dev->retries);
 270         SEQ_printf(m, "\n");
 271 }
 272
 273 static void timer_list_show_tickdevices_header(struct seq_file *m)
 274 {
 275 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 276         print_tickdevice(m, tick_get_broadcast_device(), -1);
 277         SEQ_printf(m, "tick_broadcast_mask: %*pb\n",
 278                    cpumask_pr_args(tick_get_broadcast_mask()));
 279 #ifdef CONFIG_TICK_ONESHOT
 280         SEQ_printf(m, "tick_broadcast_oneshot_mask: %*pb\n",
 281                    cpumask_pr_args(tick_get_broadcast_oneshot_mask()));
 282 #endif
 283         SEQ_printf(m, "\n");
 284 #endif
 285 }
 286 #endif
 287
 288 static inline void timer_list_header(struct seq_file *m, u64 now)
 289 {
 290         SEQ_printf(m, "Timer List Version: v0.8\n");
 291         SEQ_printf(m, "HRTIMER_MAX_CLOCK_BASES: %d\n", HRTIMER_MAX_CLOCK_BASES);
 292         SEQ_printf(m, "now at %Ld nsecs\n", (unsigned long long)now);
 293         SEQ_printf(m, "\n");
 294 }
 295
 296 static int timer_list_show(struct seq_file *m, void *v)
 297 {
 298         struct timer_list_iter *iter = v;
 299
 300         if (iter->cpu == -1 && !iter->second_pass)
 301                 timer_list_header(m, iter->now);
 302         else if (!iter->second_pass)
 303                 print_cpu(m, iter->cpu, iter->now);
 304 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 305         else if (iter->cpu == -1 && iter->second_pass)
 306                 timer_list_show_tickdevices_header(m);
 307         else
 308                 print_tickdevice(m, tick_get_device(iter->cpu), iter->cpu);
 309 #endif
 310         return 0;
 311 }
 312
 313 void sysrq_timer_list_show(void)
 314 {
 315         u64 now = ktime_to_ns(ktime_get());
 316         int cpu;
 317
 318         timer_list_header(NULL, now);
 319
 320         for_each_online_cpu(cpu)
 321                 print_cpu(NULL, cpu, now);
 322
 323 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 324         timer_list_show_tickdevices_header(NULL);
 325         for_each_online_cpu(cpu)
 326                 print_tickdevice(NULL, tick_get_device(cpu), cpu);
 327 #endif
 328         return;
 329 }
 330
 331 static void *move_iter(struct timer_list_iter *iter, loff_t offset)
 332 {
 333         for (; offset; offset--) {
 334                 iter->cpu = cpumask_next(iter->cpu, cpu_online_mask);
 335                 if (iter->cpu >= nr_cpu_ids) {
 336 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 337                         if (!iter->second_pass) {
 338                                 iter->cpu = -1;
 339                                 iter->second_pass = true;
 340                         } else
 341                                 return NULL;
 342 #else
 343                         return NULL;
 344 #endif
 345                 }
 346         }
 347         return iter;
 348 }
 349
 350 static void *timer_list_start(struct seq_file *file, loff_t *offset)
 351 {
 352         struct timer_list_iter *iter = file->private;
 353
 354         if (!*offset)
 355                 iter->now = ktime_to_ns(ktime_get());
 356         iter->cpu = -1;
 357         iter->second_pass = false;
 358         return move_iter(iter, *offset);
 359 }
 360
 361 static void *timer_list_next(struct seq_file *file, void *v, loff_t *offset)
 362 {
 363         struct timer_list_iter *iter = file->private;
 364         ++*offset;
 365         return move_iter(iter, 1);
 366 }
 367
 368 static void timer_list_stop(struct seq_file *seq, void *v)
 369 {
 370 }
 371
 372 static const struct seq_operations timer_list_sops = {
 373         .start = timer_list_start,
 374         .next = timer_list_next,
 375         .stop = timer_list_stop,
 376         .show = timer_list_show,
 377 };
 378
 379 static int timer_list_open(struct inode *inode, struct file *filp)
 380 {
 381         return seq_open_private(filp, &timer_list_sops,
 382                         sizeof(struct timer_list_iter));
 383 }
 384
 385 static const struct file_operations timer_list_fops = {
 386         .open           = timer_list_open,
 387         .read           = seq_read,
 388         .llseek         = seq_lseek,
 389         .release        = seq_release_private,
 390 };
 391
 392 static int __init init_timer_list_procfs(void)
 393 {
 394         struct proc_dir_entry *pe;
 395
 396         pe = proc_create("timer_list", 0444, NULL, &timer_list_fops);
 397         if (!pe)
 398                 return -ENOMEM;
 399         return 0;
 400 }
 401 __initcall(init_timer_list_procfs);