linux/kernel/time/timer_list.c
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   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
  25struct timer_list_iter {
  26        int cpu;
  27        bool second_pass;
  28        u64 now;
  29};
  30
  31typedef 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)
  38static 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
  52static 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
  62static void
  63print_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
  79static void
  80print_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
  88next_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
 118static void
 119print_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
 137static 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
 199static void
 200print_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
 269static 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
 284static 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
 292static int timer_list_show(struct seq_file *m, void *v)
 293{
 294        struct timer_list_iter *iter = v;
 295
 296        if (iter->cpu == -1 && !iter->second_pass)
 297                timer_list_header(m, iter->now);
 298        else if (!iter->second_pass)
 299                print_cpu(m, iter->cpu, iter->now);
 300#ifdef CONFIG_GENERIC_CLOCKEVENTS
 301        else if (iter->cpu == -1 && iter->second_pass)
 302                timer_list_show_tickdevices_header(m);
 303        else
 304                print_tickdevice(m, tick_get_device(iter->cpu), iter->cpu);
 305#endif
 306        return 0;
 307}
 308
 309void sysrq_timer_list_show(void)
 310{
 311        u64 now = ktime_to_ns(ktime_get());
 312        int cpu;
 313
 314        timer_list_header(NULL, now);
 315
 316        for_each_online_cpu(cpu)
 317                print_cpu(NULL, cpu, now);
 318
 319#ifdef CONFIG_GENERIC_CLOCKEVENTS
 320        timer_list_show_tickdevices_header(NULL);
 321        for_each_online_cpu(cpu)
 322                print_tickdevice(NULL, tick_get_device(cpu), cpu);
 323#endif
 324        return;
 325}
 326
 327static void *move_iter(struct timer_list_iter *iter, loff_t offset)
 328{
 329        for (; offset; offset--) {
 330                iter->cpu = cpumask_next(iter->cpu, cpu_online_mask);
 331                if (iter->cpu >= nr_cpu_ids) {
 332#ifdef CONFIG_GENERIC_CLOCKEVENTS
 333                        if (!iter->second_pass) {
 334                                iter->cpu = -1;
 335                                iter->second_pass = true;
 336                        } else
 337                                return NULL;
 338#else
 339                        return NULL;
 340#endif
 341                }
 342        }
 343        return iter;
 344}
 345
 346static void *timer_list_start(struct seq_file *file, loff_t *offset)
 347{
 348        struct timer_list_iter *iter = file->private;
 349
 350        if (!*offset)
 351                iter->now = ktime_to_ns(ktime_get());
 352        iter->cpu = -1;
 353        iter->second_pass = false;
 354        return move_iter(iter, *offset);
 355}
 356
 357static void *timer_list_next(struct seq_file *file, void *v, loff_t *offset)
 358{
 359        struct timer_list_iter *iter = file->private;
 360        ++*offset;
 361        return move_iter(iter, 1);
 362}
 363
 364static void timer_list_stop(struct seq_file *seq, void *v)
 365{
 366}
 367
 368static const struct seq_operations timer_list_sops = {
 369        .start = timer_list_start,
 370        .next = timer_list_next,
 371        .stop = timer_list_stop,
 372        .show = timer_list_show,
 373};
 374
 375static int timer_list_open(struct inode *inode, struct file *filp)
 376{
 377        return seq_open_private(filp, &timer_list_sops,
 378                        sizeof(struct timer_list_iter));
 379}
 380
 381static const struct file_operations timer_list_fops = {
 382        .open           = timer_list_open,
 383        .read           = seq_read,
 384        .llseek         = seq_lseek,
 385        .release        = seq_release_private,
 386};
 387
 388static int __init init_timer_list_procfs(void)
 389{
 390        struct proc_dir_entry *pe;
 391
 392        pe = proc_create("timer_list", 0400, NULL, &timer_list_fops);
 393        if (!pe)
 394                return -ENOMEM;
 395        return 0;
 396}
 397__initcall(init_timer_list_procfs);
 398