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 <asm/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 #ifdef CONFIG_TIMER_STATS
  67         char tmp[TASK_COMM_LEN + 1];
  68 #endif
  69         SEQ_printf(m, " #%d: ", idx);
  70         print_name_offset(m, taddr);
  71         SEQ_printf(m, ", ");
  72         print_name_offset(m, timer->function);
  73         SEQ_printf(m, ", S:%02x", timer->state);
  74 #ifdef CONFIG_TIMER_STATS
  75         SEQ_printf(m, ", ");
  76         print_name_offset(m, timer->start_site);
  77         memcpy(tmp, timer->start_comm, TASK_COMM_LEN);
  78         tmp[TASK_COMM_LEN] = 0;
  79         SEQ_printf(m, ", %s/%d", tmp, timer->start_pid);
  80 #endif
  81         SEQ_printf(m, "\n");
  82         SEQ_printf(m, " # expires at %Lu-%Lu nsecs [in %Ld to %Ld nsecs]\n",
  83                 (unsigned long long)ktime_to_ns(hrtimer_get_softexpires(timer)),
  84                 (unsigned long long)ktime_to_ns(hrtimer_get_expires(timer)),
  85                 (long long)(ktime_to_ns(hrtimer_get_softexpires(timer)) - now),
  86                 (long long)(ktime_to_ns(hrtimer_get_expires(timer)) - now));
  87 }
  88
  89 static void
  90 print_active_timers(struct seq_file *m, struct hrtimer_clock_base *base,
  91                     u64 now)
  92 {
  93         struct hrtimer *timer, tmp;
  94         unsigned long next = 0, i;
  95         struct timerqueue_node *curr;
  96         unsigned long flags;
  97
  98 next_one:
  99         i = 0;
 100
 101         touch_nmi_watchdog();
 102
 103         raw_spin_lock_irqsave(&base->cpu_base->lock, flags);
 104
 105         curr = timerqueue_getnext(&base->active);
 106         /*
 107          * Crude but we have to do this O(N*N) thing, because
 108          * we have to unlock the base when printing:
 109          */
 110         while (curr && i < next) {
 111                 curr = timerqueue_iterate_next(curr);
 112                 i++;
 113         }
 114
 115         if (curr) {
 116
 117                 timer = container_of(curr, struct hrtimer, node);
 118                 tmp = *timer;
 119                 raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags);
 120
 121                 print_timer(m, timer, &tmp, i, now);
 122                 next++;
 123                 goto next_one;
 124         }
 125         raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags);
 126 }
 127
 128 static void
 129 print_base(struct seq_file *m, struct hrtimer_clock_base *base, u64 now)
 130 {
 131         SEQ_printf(m, "  .base:       %pK\n", base);
 132         SEQ_printf(m, "  .index:      %d\n", base->index);
 133
 134         SEQ_printf(m, "  .resolution: %u nsecs\n", (unsigned) hrtimer_resolution);
 135
 136         SEQ_printf(m,   "  .get_time:   ");
 137         print_name_offset(m, base->get_time);
 138         SEQ_printf(m,   "\n");
 139 #ifdef CONFIG_HIGH_RES_TIMERS
 140         SEQ_printf(m, "  .offset:     %Lu nsecs\n",
 141                    (unsigned long long) ktime_to_ns(base->offset));
 142 #endif
 143         SEQ_printf(m,   "active timers:\n");
 144         print_active_timers(m, base, now + ktime_to_ns(base->offset));
 145 }
 146
 147 static void print_cpu(struct seq_file *m, int cpu, u64 now)
 148 {
 149         struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
 150         int i;
 151
 152         SEQ_printf(m, "cpu: %d\n", cpu);
 153         for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
 154                 SEQ_printf(m, " clock %d:\n", i);
 155                 print_base(m, cpu_base->clock_base + i, now);
 156         }
 157 #define P(x) \
 158         SEQ_printf(m, "  .%-15s: %Lu\n", #x, \
 159                    (unsigned long long)(cpu_base->x))
 160 #define P_ns(x) \
 161         SEQ_printf(m, "  .%-15s: %Lu nsecs\n", #x, \
 162                    (unsigned long long)(ktime_to_ns(cpu_base->x)))
 163
 164 #ifdef CONFIG_HIGH_RES_TIMERS
 165         P_ns(expires_next);
 166         P(hres_active);
 167         P(nr_events);
 168         P(nr_retries);
 169         P(nr_hangs);
 170         P(max_hang_time);
 171 #endif
 172 #undef P
 173 #undef P_ns
 174
 175 #ifdef CONFIG_TICK_ONESHOT
 176 # define P(x) \
 177         SEQ_printf(m, "  .%-15s: %Lu\n", #x, \
 178                    (unsigned long long)(ts->x))
 179 # define P_ns(x) \
 180         SEQ_printf(m, "  .%-15s: %Lu nsecs\n", #x, \
 181                    (unsigned long long)(ktime_to_ns(ts->x)))
 182         {
 183                 struct tick_sched *ts = tick_get_tick_sched(cpu);
 184                 P(nohz_mode);
 185                 P_ns(last_tick);
 186                 P(tick_stopped);
 187                 P(idle_jiffies);
 188                 P(idle_calls);
 189                 P(idle_sleeps);
 190                 P_ns(idle_entrytime);
 191                 P_ns(idle_waketime);
 192                 P_ns(idle_exittime);
 193                 P_ns(idle_sleeptime);
 194                 P_ns(iowait_sleeptime);
 195                 P(last_jiffies);
 196                 P(next_timer);
 197                 P_ns(idle_expires);
 198                 SEQ_printf(m, "jiffies: %Lu\n",
 199                            (unsigned long long)jiffies);
 200         }
 201 #endif
 202
 203 #undef P
 204 #undef P_ns
 205         SEQ_printf(m, "\n");
 206 }
 207
 208 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 209 static void
 210 print_tickdevice(struct seq_file *m, struct tick_device *td, int cpu)
 211 {
 212         struct clock_event_device *dev = td->evtdev;
 213
 214         touch_nmi_watchdog();
 215
 216         SEQ_printf(m, "Tick Device: mode:     %d\n", td->mode);
 217         if (cpu < 0)
 218                 SEQ_printf(m, "Broadcast device\n");
 219         else
 220                 SEQ_printf(m, "Per CPU device: %d\n", cpu);
 221
 222         SEQ_printf(m, "Clock Event Device: ");
 223         if (!dev) {
 224                 SEQ_printf(m, "<NULL>\n");
 225                 return;
 226         }
 227         SEQ_printf(m, "%s\n", dev->name);
 228         SEQ_printf(m, " max_delta_ns:   %llu\n",
 229                    (unsigned long long) dev->max_delta_ns);
 230         SEQ_printf(m, " min_delta_ns:   %llu\n",
 231                    (unsigned long long) dev->min_delta_ns);
 232         SEQ_printf(m, " mult:           %u\n", dev->mult);
 233         SEQ_printf(m, " shift:          %u\n", dev->shift);
 234         SEQ_printf(m, " mode:           %d\n", clockevent_get_state(dev));
 235         SEQ_printf(m, " next_event:     %Ld nsecs\n",
 236                    (unsigned long long) ktime_to_ns(dev->next_event));
 237
 238         SEQ_printf(m, " set_next_event: ");
 239         print_name_offset(m, dev->set_next_event);
 240         SEQ_printf(m, "\n");
 241
 242         if (dev->set_state_shutdown) {
 243                 SEQ_printf(m, " shutdown: ");
 244                 print_name_offset(m, dev->set_state_shutdown);
 245                 SEQ_printf(m, "\n");
 246         }
 247
 248         if (dev->set_state_periodic) {
 249                 SEQ_printf(m, " periodic: ");
 250                 print_name_offset(m, dev->set_state_periodic);
 251                 SEQ_printf(m, "\n");
 252         }
 253
 254         if (dev->set_state_oneshot) {
 255                 SEQ_printf(m, " oneshot:  ");
 256                 print_name_offset(m, dev->set_state_oneshot);
 257                 SEQ_printf(m, "\n");
 258         }
 259
 260         if (dev->set_state_oneshot_stopped) {
 261                 SEQ_printf(m, " oneshot stopped: ");
 262                 print_name_offset(m, dev->set_state_oneshot_stopped);
 263                 SEQ_printf(m, "\n");
 264         }
 265
 266         if (dev->tick_resume) {
 267                 SEQ_printf(m, " resume:   ");
 268                 print_name_offset(m, dev->tick_resume);
 269                 SEQ_printf(m, "\n");
 270         }
 271
 272         SEQ_printf(m, " event_handler:  ");
 273         print_name_offset(m, dev->event_handler);
 274         SEQ_printf(m, "\n");
 275         SEQ_printf(m, " retries:        %lu\n", dev->retries);
 276         SEQ_printf(m, "\n");
 277 }
 278
 279 static void timer_list_show_tickdevices_header(struct seq_file *m)
 280 {
 281 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 282         print_tickdevice(m, tick_get_broadcast_device(), -1);
 283         SEQ_printf(m, "tick_broadcast_mask: %*pb\n",
 284                    cpumask_pr_args(tick_get_broadcast_mask()));
 285 #ifdef CONFIG_TICK_ONESHOT
 286         SEQ_printf(m, "tick_broadcast_oneshot_mask: %*pb\n",
 287                    cpumask_pr_args(tick_get_broadcast_oneshot_mask()));
 288 #endif
 289         SEQ_printf(m, "\n");
 290 #endif
 291 }
 292 #endif
 293
 294 static inline void timer_list_header(struct seq_file *m, u64 now)
 295 {
 296         SEQ_printf(m, "Timer List Version: v0.8\n");
 297         SEQ_printf(m, "HRTIMER_MAX_CLOCK_BASES: %d\n", HRTIMER_MAX_CLOCK_BASES);
 298         SEQ_printf(m, "now at %Ld nsecs\n", (unsigned long long)now);
 299         SEQ_printf(m, "\n");
 300 }
 301
 302 void sysrq_timer_list_show(void)
 303 {
 304         u64 now = ktime_to_ns(ktime_get());
 305         int cpu;
 306
 307         timer_list_header(NULL, now);
 308
 309         for_each_online_cpu(cpu)
 310                 print_cpu(NULL, cpu, now);
 311
 312 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 313         timer_list_show_tickdevices_header(NULL);
 314         for_each_online_cpu(cpu)
 315                 print_tickdevice(NULL, tick_get_device(cpu), cpu);
 316 #endif
 317         return;
 318 }
 319
 320 #ifdef CONFIG_PROC_FS
 321 static int timer_list_show(struct seq_file *m, void *v)
 322 {
 323         struct timer_list_iter *iter = v;
 324
 325         if (iter->cpu == -1 && !iter->second_pass)
 326                 timer_list_header(m, iter->now);
 327         else if (!iter->second_pass)
 328                 print_cpu(m, iter->cpu, iter->now);
 329 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 330         else if (iter->cpu == -1 && iter->second_pass)
 331                 timer_list_show_tickdevices_header(m);
 332         else
 333                 print_tickdevice(m, tick_get_device(iter->cpu), iter->cpu);
 334 #endif
 335         return 0;
 336 }
 337
 338 static void *move_iter(struct timer_list_iter *iter, loff_t offset)
 339 {
 340         for (; offset; offset--) {
 341                 iter->cpu = cpumask_next(iter->cpu, cpu_online_mask);
 342                 if (iter->cpu >= nr_cpu_ids) {
 343 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 344                         if (!iter->second_pass) {
 345                                 iter->cpu = -1;
 346                                 iter->second_pass = true;
 347                         } else
 348                                 return NULL;
 349 #else
 350                         return NULL;
 351 #endif
 352                 }
 353         }
 354         return iter;
 355 }
 356
 357 static void *timer_list_start(struct seq_file *file, loff_t *offset)
 358 {
 359         struct timer_list_iter *iter = file->private;
 360
 361         if (!*offset)
 362                 iter->now = ktime_to_ns(ktime_get());
 363         iter->cpu = -1;
 364         iter->second_pass = false;
 365         return move_iter(iter, *offset);
 366 }
 367
 368 static void *timer_list_next(struct seq_file *file, void *v, loff_t *offset)
 369 {
 370         struct timer_list_iter *iter = file->private;
 371         ++*offset;
 372         return move_iter(iter, 1);
 373 }
 374
 375 static void timer_list_stop(struct seq_file *seq, void *v)
 376 {
 377 }
 378
 379 static const struct seq_operations timer_list_sops = {
 380         .start = timer_list_start,
 381         .next = timer_list_next,
 382         .stop = timer_list_stop,
 383         .show = timer_list_show,
 384 };
 385
 386 static int timer_list_open(struct inode *inode, struct file *filp)
 387 {
 388         return seq_open_private(filp, &timer_list_sops,
 389                         sizeof(struct timer_list_iter));
 390 }
 391
 392 static const struct file_operations timer_list_fops = {
 393         .open           = timer_list_open,
 394         .read           = seq_read,
 395         .llseek         = seq_lseek,
 396         .release        = seq_release_private,
 397 };
 398
 399 static int __init init_timer_list_procfs(void)
 400 {
 401         struct proc_dir_entry *pe;
 402
 403         pe = proc_create("timer_list", 0400, NULL, &timer_list_fops);
 404         if (!pe)
 405                 return -ENOMEM;
 406         return 0;
 407 }
 408 __initcall(init_timer_list_procfs);
 409 #endif