timer_list.c

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/*
 * kernel/time/timer_list.c
 *
 * List pending timers
 *
 * Copyright(C) 2006, Red Hat, Inc., Ingo Molnar
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/proc_fs.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/kallsyms.h>
#include <linux/tick.h>

#include <asm/uaccess.h>

typedef void (*print_fn_t)(struct seq_file *m, unsigned int *classes);

DECLARE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases);

/*
 * This allows printing both to /proc/timer_list and
 * to the console (on SysRq-Q):
 */
#define SEQ_printf(m, x...)         \
 do {                       \
    if (m)                  \
        seq_printf(m, x);       \
    else                    \
        printk(x);          \
 } while (0)

static void print_name_offset(struct seq_file *m, void *sym)
{
    char symname[KSYM_NAME_LEN];

    if (lookup_symbol_name((unsigned long)sym, symname) < 0)
        SEQ_printf(m, "<%pK>", sym);
    else
        SEQ_printf(m, "%s", symname);
}

static void
print_timer(struct seq_file *m, struct hrtimer *taddr, struct hrtimer *timer,
        int idx, u64 now)
{
#ifdef CONFIG_TIMER_STATS
    char tmp[TASK_COMM_LEN + 1];
#endif
    SEQ_printf(m, " #%d: ", idx);
    print_name_offset(m, taddr);
    SEQ_printf(m, ", ");
    print_name_offset(m, timer->function);
    SEQ_printf(m, ", S:%02lx", timer->state);
#ifdef CONFIG_TIMER_STATS
    SEQ_printf(m, ", ");
    print_name_offset(m, timer->start_site);
    memcpy(tmp, timer->start_comm, TASK_COMM_LEN);
    tmp[TASK_COMM_LEN] = 0;
    SEQ_printf(m, ", %s/%d", tmp, timer->start_pid);
#endif
    SEQ_printf(m, "\n");
    SEQ_printf(m, " # expires at %Lu-%Lu nsecs [in %Ld to %Ld nsecs]\n",
        (unsigned long long)ktime_to_ns(hrtimer_get_softexpires(timer)),
        (unsigned long long)ktime_to_ns(hrtimer_get_expires(timer)),
        (long long)(ktime_to_ns(hrtimer_get_softexpires(timer)) - now),
        (long long)(ktime_to_ns(hrtimer_get_expires(timer)) - now));
}

static void
print_active_timers(struct seq_file *m, struct hrtimer_clock_base *base,
            u64 now)
{
    struct hrtimer *timer, tmp;
    unsigned long next = 0, i;
    struct timerqueue_node *curr;
    unsigned long flags;

next_one:
    i = 0;
    raw_spin_lock_irqsave(&base->cpu_base->lock, flags);

    curr = timerqueue_getnext(&base->active);
    /*
     * Crude but we have to do this O(N*N) thing, because
     * we have to unlock the base when printing:
     */
    while (curr && i < next) {
        curr = timerqueue_iterate_next(curr);
        i++;
    }

    if (curr) {

        timer = container_of(curr, struct hrtimer, node);
        tmp = *timer;
        raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags);

        print_timer(m, timer, &tmp, i, now);
        next++;
        goto next_one;
    }
    raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags);
}

static void
print_base(struct seq_file *m, struct hrtimer_clock_base *base, u64 now)
{
    SEQ_printf(m, "  .base:       %pK\n", base);
    SEQ_printf(m, "  .index:      %d\n",
            base->index);
    SEQ_printf(m, "  .resolution: %Lu nsecs\n",
            (unsigned long long)ktime_to_ns(base->resolution));
    SEQ_printf(m,   "  .get_time:   ");
    print_name_offset(m, base->get_time);
    SEQ_printf(m,   "\n");
#ifdef CONFIG_HIGH_RES_TIMERS
    SEQ_printf(m, "  .offset:     %Lu nsecs\n",
           (unsigned long long) ktime_to_ns(base->offset));
#endif
    SEQ_printf(m,   "active timers:\n");
    print_active_timers(m, base, now);
}

static void print_cpu(struct seq_file *m, int cpu, u64 now)
{
    struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
    int i;

    SEQ_printf(m, "\n");
    SEQ_printf(m, "cpu: %d\n", cpu);
    for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
        SEQ_printf(m, " clock %d:\n", i);
        print_base(m, cpu_base->clock_base + i, now);
    }
#define P(x) \
    SEQ_printf(m, "  .%-15s: %Lu\n", #x, \
           (unsigned long long)(cpu_base->x))
#define P_ns(x) \
    SEQ_printf(m, "  .%-15s: %Lu nsecs\n", #x, \
           (unsigned long long)(ktime_to_ns(cpu_base->x)))

#ifdef CONFIG_HIGH_RES_TIMERS
    P_ns(expires_next);
    P(hres_active);
    P(nr_events);
    P(nr_retries);
    P(nr_hangs);
    P_ns(max_hang_time);
#endif
#undef P
#undef P_ns

#ifdef CONFIG_TICK_ONESHOT
# define P(x) \
    SEQ_printf(m, "  .%-15s: %Lu\n", #x, \
           (unsigned long long)(ts->x))
# define P_ns(x) \
    SEQ_printf(m, "  .%-15s: %Lu nsecs\n", #x, \
           (unsigned long long)(ktime_to_ns(ts->x)))
    {
        struct tick_sched *ts = tick_get_tick_sched(cpu);
        P(nohz_mode);
        P_ns(last_tick);
        P(tick_stopped);
        P(idle_jiffies);
        P(idle_calls);
        P(idle_sleeps);
        P_ns(idle_entrytime);
        P_ns(idle_waketime);
        P_ns(idle_exittime);
        P_ns(idle_sleeptime);
        P_ns(iowait_sleeptime);
        P(last_jiffies);
        P(next_jiffies);
        P_ns(idle_expires);
        SEQ_printf(m, "jiffies: %Lu\n",
               (unsigned long long)jiffies);
    }
#endif

#undef P
#undef P_ns
}

#ifdef CONFIG_GENERIC_CLOCKEVENTS
static void
print_tickdevice(struct seq_file *m, struct tick_device *td, int cpu)
{
    struct clock_event_device *dev = td->evtdev;

    SEQ_printf(m, "\n");
    SEQ_printf(m, "Tick Device: mode:     %d\n", td->mode);
    if (cpu < 0)
        SEQ_printf(m, "Broadcast device\n");
    else
        SEQ_printf(m, "Per CPU device: %d\n", cpu);

    SEQ_printf(m, "Clock Event Device: ");
    if (!dev) {
        SEQ_printf(m, "<NULL>\n");
        return;
    }
    SEQ_printf(m, "%s\n", dev->name);
    SEQ_printf(m, " max_delta_ns:   %llu\n",
           (unsigned long long) dev->max_delta_ns);
    SEQ_printf(m, " min_delta_ns:   %llu\n",
           (unsigned long long) dev->min_delta_ns);
    SEQ_printf(m, " mult:           %u\n", dev->mult);
    SEQ_printf(m, " shift:          %u\n", dev->shift);
    SEQ_printf(m, " mode:           %d\n", dev->mode);
    SEQ_printf(m, " next_event:     %Ld nsecs\n",
           (unsigned long long) ktime_to_ns(dev->next_event));

    SEQ_printf(m, " set_next_event: ");
    print_name_offset(m, dev->set_next_event);
    SEQ_printf(m, "\n");

    SEQ_printf(m, " set_mode:       ");
    print_name_offset(m, dev->set_mode);
    SEQ_printf(m, "\n");

    SEQ_printf(m, " event_handler:  ");
    print_name_offset(m, dev->event_handler);
    SEQ_printf(m, "\n");
    SEQ_printf(m, " retries:        %lu\n", dev->retries);
}

static void timer_list_show_tickdevices(struct seq_file *m)
{
    int cpu;

#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
    print_tickdevice(m, tick_get_broadcast_device(), -1);
    SEQ_printf(m, "tick_broadcast_mask: %08lx\n",
           cpumask_bits(tick_get_broadcast_mask())[0]);
#ifdef CONFIG_TICK_ONESHOT
    SEQ_printf(m, "tick_broadcast_oneshot_mask: %08lx\n",
           cpumask_bits(tick_get_broadcast_oneshot_mask())[0]);
#endif
    SEQ_printf(m, "\n");
#endif
    for_each_online_cpu(cpu)
        print_tickdevice(m, tick_get_device(cpu), cpu);
    SEQ_printf(m, "\n");
}
#else
static void timer_list_show_tickdevices(struct seq_file *m) { }
#endif

static int timer_list_show(struct seq_file *m, void *v)
{
    u64 now = ktime_to_ns(ktime_get());
    int cpu;

    SEQ_printf(m, "Timer List Version: v0.7\n");
    SEQ_printf(m, "HRTIMER_MAX_CLOCK_BASES: %d\n", HRTIMER_MAX_CLOCK_BASES);
    SEQ_printf(m, "now at %Ld nsecs\n", (unsigned long long)now);

    for_each_online_cpu(cpu)
        print_cpu(m, cpu, now);

    SEQ_printf(m, "\n");
    timer_list_show_tickdevices(m);

    return 0;
}

void sysrq_timer_list_show(void)
{
    timer_list_show(NULL, NULL);
}

static int timer_list_open(struct inode *inode, struct file *filp)
{
    return single_open(filp, timer_list_show, NULL);
}

static const struct file_operations timer_list_fops = {
    .open       = timer_list_open,
    .read       = seq_read,
    .llseek     = seq_lseek,
    .release    = single_release,
};

static int __init init_timer_list_procfs(void)
{
    struct proc_dir_entry *pe;

    pe = proc_create("timer_list", 0444, NULL, &timer_list_fops);
    if (!pe)
        return -ENOMEM;
    return 0;
}
__initcall(init_timer_list_procfs);