[PATCH v2 5/5] timer_list: Print name of per-cpu wakeup device

From: Will Deacon
Date: Mon May 24 2021 - 18:18:49 EST


With the introduction of per-cpu wakeup devices that can be used in
preference to the broadcast timer, print the name of such devices when
they are available.

Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Marc Zyngier <maz@xxxxxxxxxx>
Cc: Lorenzo Colitti <lorenzo@xxxxxxxxxx>
Cc: John Stultz <john.stultz@xxxxxxxxxx>
Cc: Stephen Boyd <sboyd@xxxxxxxxxx>
Signed-off-by: Will Deacon <will@xxxxxxxxxx>
---
kernel/time/tick-broadcast.c | 7 +++++++
kernel/time/tick-internal.h | 1 +
kernel/time/timer_list.c | 10 +++++++++-
3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 9b845212430b..f7fe6fe36173 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -63,6 +63,13 @@ struct cpumask *tick_get_broadcast_mask(void)
return tick_broadcast_mask;
}

+static struct clock_event_device *tick_get_oneshot_wakeup_device(int cpu);
+
+const struct clock_event_device *tick_get_wakeup_device(int cpu)
+{
+ return tick_get_oneshot_wakeup_device(cpu);
+}
+
/*
* Start the device in periodic mode
*/
diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index 30c89639e305..6a742a29e545 100644
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -71,6 +71,7 @@ extern void tick_set_periodic_handler(struct clock_event_device *dev, int broadc
extern int tick_broadcast_update_freq(struct clock_event_device *dev, u32 freq);
extern struct tick_device *tick_get_broadcast_device(void);
extern struct cpumask *tick_get_broadcast_mask(void);
+extern const struct clock_event_device *tick_get_wakeup_device(int cpu);
# else /* !CONFIG_GENERIC_CLOCKEVENTS_BROADCAST: */
static inline void tick_install_broadcast_device(struct clock_event_device *dev, int cpu) { }
static inline int tick_is_broadcast_device(struct clock_event_device *dev) { return 0; }
diff --git a/kernel/time/timer_list.c b/kernel/time/timer_list.c
index 6939140ab7c5..cca611edfd65 100644
--- a/kernel/time/timer_list.c
+++ b/kernel/time/timer_list.c
@@ -228,6 +228,14 @@ print_tickdevice(struct seq_file *m, struct tick_device *td, int cpu)
SEQ_printf(m, " event_handler: %ps\n", dev->event_handler);
SEQ_printf(m, "\n");
SEQ_printf(m, " retries: %lu\n", dev->retries);
+
+#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
+ if (cpu >= 0) {
+ const struct clock_event_device *wd =
+ tick_get_wakeup_device(cpu);
+ SEQ_printf(m, "Wakeup Device: %s\n", wd ? wd->name : "<NULL>");
+ }
+#endif
SEQ_printf(m, "\n");
}

@@ -248,7 +256,7 @@ static void timer_list_show_tickdevices_header(struct seq_file *m)

static inline void timer_list_header(struct seq_file *m, u64 now)
{
- SEQ_printf(m, "Timer List Version: v0.8\n");
+ SEQ_printf(m, "Timer List Version: v0.9\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);
SEQ_printf(m, "\n");
--
2.31.1.818.g46aad6cb9e-goog