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/tick.h>
  20
  21 #include <asm/uaccess.h>
  22
  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 DECLARE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases);
  33
  34 /*
  35  * This allows printing both to /proc/timer_list and
  36  * to the console (on SysRq-Q):
  37  */
  38 #define SEQ_printf(m, x...)                     \
  39  do {                                           \
  40         if (m)                                  \
  41                 seq_printf(m, x);               \
  42         else                                    \
  43                 printk(x);                      \
  44  } while (0)
  45
  46 static void print_name_offset(struct seq_file *m, void *sym)
  47 {
  48         char symname[KSYM_NAME_LEN];
  49
  50         if (lookup_symbol_name((unsigned long)sym, symname) < 0)
  51                 SEQ_printf(m, "<%pK>", sym);
  52         else
  53                 SEQ_printf(m, "%s", symname);
  54 }
  55
  56 static void
  57 print_timer(struct seq_file *m, struct hrtimer *taddr, struct hrtimer *timer,
  58             int idx, u64 now)
  59 {
  60 #ifdef CONFIG_TIMER_STATS
  61         char tmp[TASK_COMM_LEN + 1];
  62 #endif
  63         SEQ_printf(m, " #%d: ", idx);
  64         print_name_offset(m, taddr);
  65         SEQ_printf(m, ", ");
  66         print_name_offset(m, timer->function);
  67         SEQ_printf(m, ", S:%02lx", timer->state);
  68 #ifdef CONFIG_TIMER_STATS
  69         SEQ_printf(m, ", ");
  70         print_name_offset(m, timer->start_site);
  71         memcpy(tmp, timer->start_comm, TASK_COMM_LEN);
  72         tmp[TASK_COMM_LEN] = 0;
  73         SEQ_printf(m, ", %s/%d", tmp, timer->start_pid);
  74 #endif
  75         SEQ_printf(m, "\n");
  76         SEQ_printf(m, " # expires at %Lu-%Lu nsecs [in %Ld to %Ld nsecs]\n",
  77                 (unsigned long long)ktime_to_ns(hrtimer_get_softexpires(timer)),
  78                 (unsigned long long)ktime_to_ns(hrtimer_get_expires(timer)),
  79                 (long long)(ktime_to_ns(hrtimer_get_softexpires(timer)) - now),
  80                 (long long)(ktime_to_ns(hrtimer_get_expires(timer)) - now));
  81 }
  82
  83 static void
  84 print_active_timers(struct seq_file *m, struct hrtimer_clock_base *base,
  85                     u64 now)
  86 {
  87         struct hrtimer *timer, tmp;
  88         unsigned long next = 0, i;
  89         struct timerqueue_node *curr;
  90         unsigned long flags;
  91
  92 next_one:
  93         i = 0;
  94         raw_spin_lock_irqsave(&base->cpu_base->lock, flags);
  95
  96         curr = timerqueue_getnext(&base->active);
  97         /*
  98          * Crude but we have to do this O(N*N) thing, because
  99          * we have to unlock the base when printing:
 100          */
 101         while (curr && i < next) {
 102                 curr = timerqueue_iterate_next(curr);
 103                 i++;
 104         }
 105
 106         if (curr) {
 107
 108                 timer = container_of(curr, struct hrtimer, node);
 109                 tmp = *timer;
 110                 raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags);
 111
 112                 print_timer(m, timer, &tmp, i, now);
 113                 next++;
 114                 goto next_one;
 115         }
 116         raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags);
 117 }
 118
 119 static void
 120 print_base(struct seq_file *m, struct hrtimer_clock_base *base, u64 now)
 121 {
 122         SEQ_printf(m, "  .base:       %pK\n", base);
 123         SEQ_printf(m, "  .index:      %d\n",
 124                         base->index);
 125         SEQ_printf(m, "  .resolution: %Lu nsecs\n",
 126                         (unsigned long long)ktime_to_ns(base->resolution));
 127         SEQ_printf(m,   "  .get_time:   ");
 128         print_name_offset(m, base->get_time);
 129         SEQ_printf(m,   "\n");
 130 #ifdef CONFIG_HIGH_RES_TIMERS
 131         SEQ_printf(m, "  .offset:     %Lu nsecs\n",
 132                    (unsigned long long) ktime_to_ns(base->offset));
 133 #endif
 134         SEQ_printf(m,   "active timers:\n");
 135         print_active_timers(m, base, now);
 136 }
 137
 138 static void print_cpu(struct seq_file *m, int cpu, u64 now)
 139 {
 140         struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
 141         int i;
 142
 143         SEQ_printf(m, "cpu: %d\n", cpu);
 144         for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
 145                 SEQ_printf(m, " clock %d:\n", i);
 146                 print_base(m, cpu_base->clock_base + i, now);
 147         }
 148 #define P(x) \
 149         SEQ_printf(m, "  .%-15s: %Lu\n", #x, \
 150                    (unsigned long long)(cpu_base->x))
 151 #define P_ns(x) \
 152         SEQ_printf(m, "  .%-15s: %Lu nsecs\n", #x, \
 153                    (unsigned long long)(ktime_to_ns(cpu_base->x)))
 154
 155 #ifdef CONFIG_HIGH_RES_TIMERS
 156         P_ns(expires_next);
 157         P(hres_active);
 158         P(nr_events);
 159         P(nr_retries);
 160         P(nr_hangs);
 161         P_ns(max_hang_time);
 162 #endif
 163 #undef P
 164 #undef P_ns
 165
 166 #ifdef CONFIG_TICK_ONESHOT
 167 # define P(x) \
 168         SEQ_printf(m, "  .%-15s: %Lu\n", #x, \
 169                    (unsigned long long)(ts->x))
 170 # define P_ns(x) \
 171         SEQ_printf(m, "  .%-15s: %Lu nsecs\n", #x, \
 172                    (unsigned long long)(ktime_to_ns(ts->x)))
 173         {
 174                 struct tick_sched *ts = tick_get_tick_sched(cpu);
 175                 P(nohz_mode);
 176                 P_ns(last_tick);
 177                 P(tick_stopped);
 178                 P(idle_jiffies);
 179                 P(idle_calls);
 180                 P(idle_sleeps);
 181                 P_ns(idle_entrytime);
 182                 P_ns(idle_waketime);
 183                 P_ns(idle_exittime);
 184                 P_ns(idle_sleeptime);
 185                 P_ns(iowait_sleeptime);
 186                 P(last_jiffies);
 187                 P(next_jiffies);
 188                 P_ns(idle_expires);
 189                 SEQ_printf(m, "jiffies: %Lu\n",
 190                            (unsigned long long)jiffies);
 191         }
 192 #endif
 193
 194 #undef P
 195 #undef P_ns
 196         SEQ_printf(m, "\n");
 197 }
 198
 199 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 200 static void
 201 print_tickdevice(struct seq_file *m, struct tick_device *td, int cpu)
 202 {
 203         struct clock_event_device *dev = td->evtdev;
 204
 205         SEQ_printf(m, "Tick Device: mode:     %d\n", td->mode);
 206         if (cpu < 0)
 207                 SEQ_printf(m, "Broadcast device\n");
 208         else
 209                 SEQ_printf(m, "Per CPU device: %d\n", cpu);
 210
 211         SEQ_printf(m, "Clock Event Device: ");
 212         if (!dev) {
 213                 SEQ_printf(m, "<NULL>\n");
 214                 return;
 215         }
 216         SEQ_printf(m, "%s\n", dev->name);
 217         SEQ_printf(m, " max_delta_ns:   %llu\n",
 218                    (unsigned long long) dev->max_delta_ns);
 219         SEQ_printf(m, " min_delta_ns:   %llu\n",
 220                    (unsigned long long) dev->min_delta_ns);
 221         SEQ_printf(m, " mult:           %u\n", dev->mult);
 222         SEQ_printf(m, " shift:          %u\n", dev->shift);
 223         SEQ_printf(m, " mode:           %d\n", dev->mode);
 224         SEQ_printf(m, " next_event:     %Ld nsecs\n",
 225                    (unsigned long long) ktime_to_ns(dev->next_event));
 226
 227         SEQ_printf(m, " set_next_event: ");
 228         print_name_offset(m, dev->set_next_event);
 229         SEQ_printf(m, "\n");
 230
 231         SEQ_printf(m, " set_mode:       ");
 232         print_name_offset(m, dev->set_mode);
 233         SEQ_printf(m, "\n");
 234
 235         SEQ_printf(m, " event_handler:  ");
 236         print_name_offset(m, dev->event_handler);
 237         SEQ_printf(m, "\n");
 238         SEQ_printf(m, " retries:        %lu\n", dev->retries);
 239         SEQ_printf(m, "\n");
 240 }
 241
 242 static void timer_list_show_tickdevices_header(struct seq_file *m)
 243 {
 244 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 245         print_tickdevice(m, tick_get_broadcast_device(), -1);
 246         SEQ_printf(m, "tick_broadcast_mask: %08lx\n",
 247                    cpumask_bits(tick_get_broadcast_mask())[0]);
 248 #ifdef CONFIG_TICK_ONESHOT
 249         SEQ_printf(m, "tick_broadcast_oneshot_mask: %08lx\n",
 250                    cpumask_bits(tick_get_broadcast_oneshot_mask())[0]);
 251 #endif
 252         SEQ_printf(m, "\n");
 253 #endif
 254 }
 255 #endif
 256
 257 static inline void timer_list_header(struct seq_file *m, u64 now)
 258 {
 259         SEQ_printf(m, "Timer List Version: v0.7\n");
 260         SEQ_printf(m, "HRTIMER_MAX_CLOCK_BASES: %d\n", HRTIMER_MAX_CLOCK_BASES);
 261         SEQ_printf(m, "now at %Ld nsecs\n", (unsigned long long)now);
 262         SEQ_printf(m, "\n");
 263 }
 264
 265 static int timer_list_show(struct seq_file *m, void *v)
 266 {
 267         struct timer_list_iter *iter = v;
 268
 269         if (iter->cpu == -1 && !iter->second_pass)
 270                 timer_list_header(m, iter->now);
 271         else if (!iter->second_pass)
 272                 print_cpu(m, iter->cpu, iter->now);
 273 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 274         else if (iter->cpu == -1 && iter->second_pass)
 275                 timer_list_show_tickdevices_header(m);
 276         else
 277                 print_tickdevice(m, tick_get_device(iter->cpu), iter->cpu);
 278 #endif
 279         return 0;
 280 }
 281
 282 void sysrq_timer_list_show(void)
 283 {
 284         u64 now = ktime_to_ns(ktime_get());
 285         int cpu;
 286
 287         timer_list_header(NULL, now);
 288
 289         for_each_online_cpu(cpu)
 290                 print_cpu(NULL, cpu, now);
 291
 292 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 293         timer_list_show_tickdevices_header(NULL);
 294         for_each_online_cpu(cpu)
 295                 print_tickdevice(NULL, tick_get_device(cpu), cpu);
 296 #endif
 297         return;
 298 }
 299
 300 static void *move_iter(struct timer_list_iter *iter, loff_t offset)
 301 {
 302         for (; offset; offset--) {
 303                 iter->cpu = cpumask_next(iter->cpu, cpu_online_mask);
 304                 if (iter->cpu >= nr_cpu_ids) {
 305 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 306                         if (!iter->second_pass) {
 307                                 iter->cpu = -1;
 308                                 iter->second_pass = true;
 309                         } else
 310                                 return NULL;
 311 #else
 312                         return NULL;
 313 #endif
 314                 }
 315         }
 316         return iter;
 317 }
 318
 319 static void *timer_list_start(struct seq_file *file, loff_t *offset)
 320 {
 321         struct timer_list_iter *iter = file->private;
 322
 323         if (!*offset)
 324                 iter->now = ktime_to_ns(ktime_get());
 325         iter->cpu = -1;
 326         iter->second_pass = false;
 327         return move_iter(iter, *offset);
 328 }
 329
 330 static void *timer_list_next(struct seq_file *file, void *v, loff_t *offset)
 331 {
 332         struct timer_list_iter *iter = file->private;
 333         ++*offset;
 334         return move_iter(iter, 1);
 335 }
 336
 337 static void timer_list_stop(struct seq_file *seq, void *v)
 338 {
 339 }
 340
 341 static const struct seq_operations timer_list_sops = {
 342         .start = timer_list_start,
 343         .next = timer_list_next,
 344         .stop = timer_list_stop,
 345         .show = timer_list_show,
 346 };
 347
 348 static int timer_list_open(struct inode *inode, struct file *filp)
 349 {
 350         return seq_open_private(filp, &timer_list_sops,
 351                         sizeof(struct timer_list_iter));
 352 }
 353
 354 static const struct file_operations timer_list_fops = {
 355         .open           = timer_list_open,
 356         .read           = seq_read,
 357         .llseek         = seq_lseek,
 358         .release        = seq_release_private,
 359 };
 360
 361 static int __init init_timer_list_procfs(void)
 362 {
 363         struct proc_dir_entry *pe;
 364
 365         pe = proc_create("timer_list", 0444, NULL, &timer_list_fops);
 366         if (!pe)
 367                 return -ENOMEM;
 368         return 0;
 369 }
 370 __initcall(init_timer_list_procfs);