[PATCH v10 17/20] timers: Introduce function to check timer base is_idle flag

Anna-Maria Behnsen
2024-01-15T14:38:14Z

flag

To prepare for the conversion of the NOHZ timer placement to a pull at
expiry time model it's required to have a function that returns the value
of the is_idle flag of the timer base to keep the hierarchy states during
online in sync with timer base state.

No functional change.

Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
---
v10: Fix fallout of 0day: Move function definition of timer_base_is_idle()
into SMP && NO_HZ_COMMON ifdef section

v9: new in v9
---
kernel/time/tick-internal.h | 1 +
kernel/time/timer.c | 10 ++++++++++
2 files changed, 11 insertions(+)

diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index ccf39befde85..7e3090109e33 100644
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -165,6 +165,7 @@ extern void fetch_next_timer_interrupt_remote(unsigned long basej, u64 basem,
unsigned int cpu);
extern void timer_lock_remote_bases(unsigned int cpu);
extern void timer_unlock_remote_bases(unsigned int cpu);
+extern bool timer_base_is_idle(void);
# endif
#else /* CONFIG_NO_HZ_COMMON */
static inline void timers_update_nohz(void) { }
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index eb99297a96fe..3c49d8fdfd53 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -2099,6 +2099,16 @@ void timer_lock_remote_bases(unsigned int cpu)
raw_spin_lock(&base_local->lock);
raw_spin_lock_nested(&base_global->lock, SINGLE_DEPTH_NESTING);
}
+
+/**
+ * timer_base_is_idle() - Return whether timer base is set idle
+ *
+ * Returns value of local timer base is_idle value.
+ */
+bool timer_base_is_idle(void)
+{
+ return __this_cpu_read(timer_bases[BASE_LOCAL].is_idle);
+}
# endif /* CONFIG_SMP */

static inline u64 __get_next_timer_interrupt(unsigned long basej, u64 basem,
--
2.39.2