[PATCH v6 1/6] timers: Rename tmigr 'online' bit to 'available'

Gabriele Monaco
2025-05-30T14:21:24Z

The timer migration hierarchy excludes offline CPUs via the
tmigr_is_not_available function, which is essentially checking the
online bit for the CPU.

Rename the online bit to available and all references in function names
and tracepoint to generalise the concept of available CPUs.

Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
---
include/trace/events/timer_migration.h | 4 ++--
kernel/time/timer_migration.c | 22 +++++++++++-----------
kernel/time/timer_migration.h | 2 +-
3 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/include/trace/events/timer_migration.h b/include/trace/events/timer_migration.h
index 47db5eaf2f9ab..61171b13c687c 100644
--- a/include/trace/events/timer_migration.h
+++ b/include/trace/events/timer_migration.h
@@ -173,14 +173,14 @@ DEFINE_EVENT(tmigr_cpugroup, tmigr_cpu_active,
TP_ARGS(tmc)
);

-DEFINE_EVENT(tmigr_cpugroup, tmigr_cpu_online,
+DEFINE_EVENT(tmigr_cpugroup, tmigr_cpu_available,

TP_PROTO(struct tmigr_cpu *tmc),

TP_ARGS(tmc)
);

-DEFINE_EVENT(tmigr_cpugroup, tmigr_cpu_offline,
+DEFINE_EVENT(tmigr_cpugroup, tmigr_cpu_unavailable,

TP_PROTO(struct tmigr_cpu *tmc),

diff --git a/kernel/time/timer_migration.c b/kernel/time/timer_migration.c
index 2f6330831f084..7efd897c79599 100644
--- a/kernel/time/timer_migration.c
+++ b/kernel/time/timer_migration.c
@@ -427,7 +427,7 @@ static DEFINE_PER_CPU(struct tmigr_cpu, tmigr_cpu);

static inline bool tmigr_is_not_available(struct tmigr_cpu *tmc)
{
- return !(tmc->tmgroup && tmc->online);
+ return !(tmc->tmgroup && tmc->available);
}

/*
@@ -926,7 +926,7 @@ static void tmigr_handle_remote_cpu(unsigned int cpu, u64 now,
* updated the event takes care when hierarchy is completely
* idle. Otherwise the migrator does it as the event is enqueued.
*/
- if (!tmc->online || tmc->remote || tmc->cpuevt.ignore ||
+ if (!tmc->available || tmc->remote || tmc->cpuevt.ignore ||
now < tmc->cpuevt.nextevt.expires) {
raw_spin_unlock_irq(&tmc->lock);
return;
@@ -973,7 +973,7 @@ static void tmigr_handle_remote_cpu(unsigned int cpu, u64 now,
* (See also section "Required event and timerqueue update after a
* remote expiry" in the documentation at the top)
*/
- if (!tmc->online || !tmc->idle) {
+ if (!tmc->available || !tmc->idle) {
timer_unlock_remote_bases(cpu);
goto unlock;
}
@@ -1435,19 +1435,19 @@ static long tmigr_trigger_active(void *unused)
{
struct tmigr_cpu *tmc = this_cpu_ptr(&tmigr_cpu);

- WARN_ON_ONCE(!tmc->online || tmc->idle);
+ WARN_ON_ONCE(!tmc->available || tmc->idle);

return 0;
}

-static int tmigr_cpu_offline(unsigned int cpu)
+static int tmigr_cpu_unavailable(unsigned int cpu)
{
struct tmigr_cpu *tmc = this_cpu_ptr(&tmigr_cpu);
int migrator;
u64 firstexp;

raw_spin_lock_irq(&tmc->lock);
- tmc->online = false;
+ tmc->available = false;
WRITE_ONCE(tmc->wakeup, KTIME_MAX);

/*
@@ -1455,7 +1455,7 @@ static int tmigr_cpu_offline(unsigned int cpu)
* offline; Therefore nextevt value is set to KTIME_MAX
*/
firstexp = __tmigr_cpu_deactivate(tmc, KTIME_MAX);
- trace_tmigr_cpu_offline(tmc);
+ trace_tmigr_cpu_unavailable(tmc);
raw_spin_unlock_irq(&tmc->lock);

if (firstexp != KTIME_MAX) {
@@ -1466,7 +1466,7 @@ static int tmigr_cpu_offline(unsigned int cpu)
return 0;
}

-static int tmigr_cpu_online(unsigned int cpu)
+static int tmigr_cpu_available(unsigned int cpu)
{
struct tmigr_cpu *tmc = this_cpu_ptr(&tmigr_cpu);

@@ -1475,11 +1475,11 @@ static int tmigr_cpu_online(unsigned int cpu)
return -EINVAL;

raw_spin_lock_irq(&tmc->lock);
- trace_tmigr_cpu_online(tmc);
+ trace_tmigr_cpu_available(tmc);
tmc->idle = timer_base_is_idle();
if (!tmc->idle)
__tmigr_cpu_activate(tmc);
- tmc->online = true;
+ tmc->available = true;
raw_spin_unlock_irq(&tmc->lock);
return 0;
}
@@ -1850,7 +1850,7 @@ static int __init tmigr_init(void)
goto err;

ret = cpuhp_setup_state(CPUHP_AP_TMIGR_ONLINE, "tmigr:online",
- tmigr_cpu_online, tmigr_cpu_offline);
+ tmigr_cpu_available, tmigr_cpu_unavailable);
if (ret)
goto err;

diff --git a/kernel/time/timer_migration.h b/kernel/time/timer_migration.h
index ae19f70f8170f..70879cde6fdd0 100644
--- a/kernel/time/timer_migration.h
+++ b/kernel/time/timer_migration.h
@@ -97,7 +97,7 @@ struct tmigr_group {
*/
struct tmigr_cpu {
raw_spinlock_t lock;
- bool online;
+ bool available;
bool idle;
bool remote;
struct tmigr_group *tmgroup;
--
2.49.0