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https://github.com/torvalds/linux
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![Frederic Weisbecker](/assets/img/avatar_default.png)
The nohz mode field tells about low resolution nohz mode or high resolution nohz mode but it doesn't tell about high resolution non-nohz mode. In order to retrieve the latter state, tick_cancel_sched_timer() must fiddle with struct hrtimer's internals to guess if the tick has been initialized in high resolution. Move instead the nohz mode field information into the tick flags and provide two new bits: one to know if the tick is in nohz mode and another one to know if the tick is in high resolution. The combination of those two flags provides all the needed informations to determine which of the three tick modes is running. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20240225225508.11587-14-frederic@kernel.org
365 lines
8.7 KiB
C
365 lines
8.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* List pending timers
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*
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* Copyright(C) 2006, Red Hat, Inc., Ingo Molnar
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*/
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#include <linux/proc_fs.h>
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#include <linux/module.h>
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#include <linux/spinlock.h>
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#include <linux/sched.h>
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#include <linux/seq_file.h>
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#include <linux/kallsyms.h>
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#include <linux/nmi.h>
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#include <linux/uaccess.h>
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#include "tick-internal.h"
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struct timer_list_iter {
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int cpu;
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bool second_pass;
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u64 now;
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};
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/*
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* This allows printing both to /proc/timer_list and
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* to the console (on SysRq-Q):
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*/
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__printf(2, 3)
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static void SEQ_printf(struct seq_file *m, const char *fmt, ...)
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{
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va_list args;
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va_start(args, fmt);
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if (m)
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seq_vprintf(m, fmt, args);
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else
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vprintk(fmt, args);
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va_end(args);
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}
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static void
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print_timer(struct seq_file *m, struct hrtimer *taddr, struct hrtimer *timer,
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int idx, u64 now)
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{
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SEQ_printf(m, " #%d: <%pK>, %ps", idx, taddr, timer->function);
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SEQ_printf(m, ", S:%02x", timer->state);
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SEQ_printf(m, "\n");
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SEQ_printf(m, " # expires at %Lu-%Lu nsecs [in %Ld to %Ld nsecs]\n",
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(unsigned long long)ktime_to_ns(hrtimer_get_softexpires(timer)),
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(unsigned long long)ktime_to_ns(hrtimer_get_expires(timer)),
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(long long)(ktime_to_ns(hrtimer_get_softexpires(timer)) - now),
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(long long)(ktime_to_ns(hrtimer_get_expires(timer)) - now));
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}
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static void
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print_active_timers(struct seq_file *m, struct hrtimer_clock_base *base,
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u64 now)
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{
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struct hrtimer *timer, tmp;
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unsigned long next = 0, i;
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struct timerqueue_node *curr;
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unsigned long flags;
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next_one:
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i = 0;
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touch_nmi_watchdog();
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raw_spin_lock_irqsave(&base->cpu_base->lock, flags);
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curr = timerqueue_getnext(&base->active);
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/*
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* Crude but we have to do this O(N*N) thing, because
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* we have to unlock the base when printing:
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*/
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while (curr && i < next) {
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curr = timerqueue_iterate_next(curr);
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i++;
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}
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if (curr) {
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timer = container_of(curr, struct hrtimer, node);
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tmp = *timer;
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raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags);
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print_timer(m, timer, &tmp, i, now);
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next++;
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goto next_one;
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}
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raw_spin_unlock_irqrestore(&base->cpu_base->lock, flags);
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}
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static void
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print_base(struct seq_file *m, struct hrtimer_clock_base *base, u64 now)
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{
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SEQ_printf(m, " .base: %pK\n", base);
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SEQ_printf(m, " .index: %d\n", base->index);
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SEQ_printf(m, " .resolution: %u nsecs\n", hrtimer_resolution);
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SEQ_printf(m, " .get_time: %ps\n", base->get_time);
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#ifdef CONFIG_HIGH_RES_TIMERS
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SEQ_printf(m, " .offset: %Lu nsecs\n",
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(unsigned long long) ktime_to_ns(base->offset));
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#endif
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SEQ_printf(m, "active timers:\n");
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print_active_timers(m, base, now + ktime_to_ns(base->offset));
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}
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static void print_cpu(struct seq_file *m, int cpu, u64 now)
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{
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struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
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int i;
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SEQ_printf(m, "cpu: %d\n", cpu);
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for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
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SEQ_printf(m, " clock %d:\n", i);
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print_base(m, cpu_base->clock_base + i, now);
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}
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#define P(x) \
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SEQ_printf(m, " .%-15s: %Lu\n", #x, \
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(unsigned long long)(cpu_base->x))
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#define P_ns(x) \
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SEQ_printf(m, " .%-15s: %Lu nsecs\n", #x, \
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(unsigned long long)(ktime_to_ns(cpu_base->x)))
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#ifdef CONFIG_HIGH_RES_TIMERS
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P_ns(expires_next);
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P(hres_active);
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P(nr_events);
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P(nr_retries);
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P(nr_hangs);
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P(max_hang_time);
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#endif
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#undef P
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#undef P_ns
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#ifdef CONFIG_TICK_ONESHOT
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# define P(x) \
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SEQ_printf(m, " .%-15s: %Lu\n", #x, \
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(unsigned long long)(ts->x))
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# define P_ns(x) \
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SEQ_printf(m, " .%-15s: %Lu nsecs\n", #x, \
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(unsigned long long)(ktime_to_ns(ts->x)))
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# define P_flag(x, f) \
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SEQ_printf(m, " .%-15s: %d\n", #x, !!(ts->flags & (f)))
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{
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struct tick_sched *ts = tick_get_tick_sched(cpu);
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P_flag(nohz, TS_FLAG_NOHZ);
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P_flag(highres, TS_FLAG_HIGHRES);
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P_ns(last_tick);
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P_flag(tick_stopped, TS_FLAG_STOPPED);
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P(idle_jiffies);
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P(idle_calls);
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P(idle_sleeps);
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P_ns(idle_entrytime);
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P_ns(idle_waketime);
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P_ns(idle_exittime);
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P_ns(idle_sleeptime);
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P_ns(iowait_sleeptime);
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P(last_jiffies);
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P(next_timer);
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P_ns(idle_expires);
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SEQ_printf(m, "jiffies: %Lu\n",
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(unsigned long long)jiffies);
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}
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#endif
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#undef P
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#undef P_ns
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SEQ_printf(m, "\n");
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}
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#ifdef CONFIG_GENERIC_CLOCKEVENTS
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static void
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print_tickdevice(struct seq_file *m, struct tick_device *td, int cpu)
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{
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struct clock_event_device *dev = td->evtdev;
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touch_nmi_watchdog();
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SEQ_printf(m, "Tick Device: mode: %d\n", td->mode);
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if (cpu < 0)
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SEQ_printf(m, "Broadcast device\n");
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else
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SEQ_printf(m, "Per CPU device: %d\n", cpu);
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SEQ_printf(m, "Clock Event Device: ");
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if (!dev) {
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SEQ_printf(m, "<NULL>\n");
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return;
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}
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SEQ_printf(m, "%s\n", dev->name);
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SEQ_printf(m, " max_delta_ns: %llu\n",
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(unsigned long long) dev->max_delta_ns);
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SEQ_printf(m, " min_delta_ns: %llu\n",
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(unsigned long long) dev->min_delta_ns);
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SEQ_printf(m, " mult: %u\n", dev->mult);
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SEQ_printf(m, " shift: %u\n", dev->shift);
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SEQ_printf(m, " mode: %d\n", clockevent_get_state(dev));
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SEQ_printf(m, " next_event: %Ld nsecs\n",
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(unsigned long long) ktime_to_ns(dev->next_event));
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SEQ_printf(m, " set_next_event: %ps\n", dev->set_next_event);
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if (dev->set_state_shutdown)
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SEQ_printf(m, " shutdown: %ps\n",
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dev->set_state_shutdown);
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if (dev->set_state_periodic)
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SEQ_printf(m, " periodic: %ps\n",
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dev->set_state_periodic);
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if (dev->set_state_oneshot)
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SEQ_printf(m, " oneshot: %ps\n",
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dev->set_state_oneshot);
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if (dev->set_state_oneshot_stopped)
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SEQ_printf(m, " oneshot stopped: %ps\n",
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dev->set_state_oneshot_stopped);
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if (dev->tick_resume)
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SEQ_printf(m, " resume: %ps\n",
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dev->tick_resume);
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SEQ_printf(m, " event_handler: %ps\n", dev->event_handler);
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SEQ_printf(m, "\n");
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SEQ_printf(m, " retries: %lu\n", dev->retries);
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#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
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if (cpu >= 0) {
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const struct clock_event_device *wd = tick_get_wakeup_device(cpu);
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SEQ_printf(m, "Wakeup Device: %s\n", wd ? wd->name : "<NULL>");
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}
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#endif
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SEQ_printf(m, "\n");
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}
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static void timer_list_show_tickdevices_header(struct seq_file *m)
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{
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#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
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print_tickdevice(m, tick_get_broadcast_device(), -1);
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SEQ_printf(m, "tick_broadcast_mask: %*pb\n",
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cpumask_pr_args(tick_get_broadcast_mask()));
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#ifdef CONFIG_TICK_ONESHOT
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SEQ_printf(m, "tick_broadcast_oneshot_mask: %*pb\n",
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cpumask_pr_args(tick_get_broadcast_oneshot_mask()));
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#endif
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SEQ_printf(m, "\n");
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#endif
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}
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#endif
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static inline void timer_list_header(struct seq_file *m, u64 now)
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{
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SEQ_printf(m, "Timer List Version: v0.10\n");
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SEQ_printf(m, "HRTIMER_MAX_CLOCK_BASES: %d\n", HRTIMER_MAX_CLOCK_BASES);
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SEQ_printf(m, "now at %Ld nsecs\n", (unsigned long long)now);
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SEQ_printf(m, "\n");
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}
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void sysrq_timer_list_show(void)
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{
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u64 now = ktime_to_ns(ktime_get());
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int cpu;
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timer_list_header(NULL, now);
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for_each_online_cpu(cpu)
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print_cpu(NULL, cpu, now);
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#ifdef CONFIG_GENERIC_CLOCKEVENTS
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timer_list_show_tickdevices_header(NULL);
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for_each_online_cpu(cpu)
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print_tickdevice(NULL, tick_get_device(cpu), cpu);
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#endif
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return;
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}
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#ifdef CONFIG_PROC_FS
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static int timer_list_show(struct seq_file *m, void *v)
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{
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struct timer_list_iter *iter = v;
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if (iter->cpu == -1 && !iter->second_pass)
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timer_list_header(m, iter->now);
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else if (!iter->second_pass)
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print_cpu(m, iter->cpu, iter->now);
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#ifdef CONFIG_GENERIC_CLOCKEVENTS
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else if (iter->cpu == -1 && iter->second_pass)
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timer_list_show_tickdevices_header(m);
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else
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print_tickdevice(m, tick_get_device(iter->cpu), iter->cpu);
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#endif
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return 0;
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}
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static void *move_iter(struct timer_list_iter *iter, loff_t offset)
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{
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for (; offset; offset--) {
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iter->cpu = cpumask_next(iter->cpu, cpu_online_mask);
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if (iter->cpu >= nr_cpu_ids) {
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#ifdef CONFIG_GENERIC_CLOCKEVENTS
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if (!iter->second_pass) {
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iter->cpu = -1;
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iter->second_pass = true;
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} else
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return NULL;
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#else
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return NULL;
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#endif
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}
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}
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return iter;
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}
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static void *timer_list_start(struct seq_file *file, loff_t *offset)
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{
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struct timer_list_iter *iter = file->private;
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if (!*offset)
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iter->now = ktime_to_ns(ktime_get());
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iter->cpu = -1;
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iter->second_pass = false;
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return move_iter(iter, *offset);
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}
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static void *timer_list_next(struct seq_file *file, void *v, loff_t *offset)
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{
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struct timer_list_iter *iter = file->private;
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++*offset;
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return move_iter(iter, 1);
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}
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static void timer_list_stop(struct seq_file *seq, void *v)
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{
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}
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static const struct seq_operations timer_list_sops = {
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.start = timer_list_start,
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.next = timer_list_next,
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.stop = timer_list_stop,
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.show = timer_list_show,
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};
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static int __init init_timer_list_procfs(void)
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{
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struct proc_dir_entry *pe;
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pe = proc_create_seq_private("timer_list", 0400, NULL, &timer_list_sops,
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sizeof(struct timer_list_iter), NULL);
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if (!pe)
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return -ENOMEM;
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return 0;
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}
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__initcall(init_timer_list_procfs);
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#endif
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