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| author | Thomas Gleixner <tglx@kernel.org> | 2026-04-08 13:54:01 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@kernel.org> | 2026-05-01 21:36:12 +0200 |
| commit | cfb7fe3fdd4ca1d37da1ed15a1897d4a27c47a8a (patch) | |
| tree | 0df10623b12923494bda0a8f8b5c15c7fb1c48ff | |
| parent | 6fdb2677a594ab38eade927919bbd4d9688bfa1c (diff) | |
| download | linux-cfb7fe3fdd4ca1d37da1ed15a1897d4a27c47a8a.tar.gz linux-cfb7fe3fdd4ca1d37da1ed15a1897d4a27c47a8a.zip | |
posix-timers: Handle the timer_[re]arm() return value
The [re]arm callbacks will return true when the timer was queued and false
if it was already expired at enqueue time.
In both cases the call sites can trivially queue the signal right there,
when the timer was already expired. That avoids a full round trip through
the hrtimer interrupt.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260408114952.198028466@kernel.org
| -rw-r--r-- | kernel/time/posix-timers.c | 22 |
1 files changed, 17 insertions, 5 deletions
diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c index da04ed42bf82..db62cfac169d 100644 --- a/kernel/time/posix-timers.c +++ b/kernel/time/posix-timers.c @@ -299,6 +299,8 @@ static bool common_hrtimer_rearm(struct k_itimer *timr) static bool __posixtimer_deliver_signal(struct kernel_siginfo *info, struct k_itimer *timr) { + bool queued; + guard(spinlock)(&timr->it_lock); /* @@ -312,12 +314,18 @@ static bool __posixtimer_deliver_signal(struct kernel_siginfo *info, struct k_it if (!timr->it_interval || WARN_ON_ONCE(timr->it_status != POSIX_TIMER_REQUEUE_PENDING)) return true; - timr->kclock->timer_rearm(timr); - timr->it_status = POSIX_TIMER_ARMED; + /* timer_rearm() updates timr::it_overrun */ + queued = timr->kclock->timer_rearm(timr); + timr->it_overrun_last = timr->it_overrun; timr->it_overrun = -1LL; ++timr->it_signal_seq; info->si_overrun = timer_overrun_to_int(timr); + + if (queued) + timr->it_status = POSIX_TIMER_ARMED; + else + posix_timer_queue_signal(timr); return true; } @@ -905,9 +913,13 @@ int common_timer_set(struct k_itimer *timr, int flags, expires = timens_ktime_to_host(timr->it_clock, expires); sigev_none = timr->it_sigev_notify == SIGEV_NONE; - kc->timer_arm(timr, expires, flags & TIMER_ABSTIME, sigev_none); - if (!sigev_none) - timr->it_status = POSIX_TIMER_ARMED; + if (kc->timer_arm(timr, expires, flags & TIMER_ABSTIME, sigev_none)) { + if (!sigev_none) + timr->it_status = POSIX_TIMER_ARMED; + } else { + /* Timer was already expired, queue the signal */ + posix_timer_queue_signal(timr); + } return 0; } |