2023-06-06 15:10:38

by Thomas Gleixner

[permalink] [raw]
Subject: [patch 16/45] posix-timers: Consolidate timer setup

hrtimer based and CPU timers have their own way to install the new interval
and to reset overrun and signal handling related data.

Create a helper function and do the same operation for all variants.

Signed-off-by: Thomas Gleixner <[email protected]>
---
kernel/time/posix-cpu-timers.c | 15 +--------------
kernel/time/posix-timers.c | 23 +++++++++++++++++------
kernel/time/posix-timers.h | 1 +
3 files changed, 19 insertions(+), 20 deletions(-)

--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -709,21 +709,8 @@ static int posix_cpu_timer_set(struct k_
trigger_base_recalc_expires(timer, p);

unlock_task_sighand(p, &flags);
- /*
- * Install the new reload setting, and
- * set up the signal and overrun bookkeeping.
- */
- timer->it_interval = timespec64_to_ktime(new->it_interval);

- /*
- * This acts as a modification timestamp for the timer,
- * so any automatic reload attempt will punt on seeing
- * that we have reset the timer manually.
- */
- timer->it_requeue_pending = (timer->it_requeue_pending + 2) &
- ~REQUEUE_PENDING;
- timer->it_overrun_last = 0;
- timer->it_overrun = -1;
+ posix_timer_set_common(timer, new);

/*
* If the new expiry time was already in the past the timer was not
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -853,6 +853,21 @@ static struct k_itimer *timer_wait_runni
return lock_timer(timer_id, flags);
}

+/*
+ * Set up the new interval and reset the signal delivery data
+ */
+void posix_timer_set_common(struct k_itimer *timer, struct itimerspec64 *new_setting)
+{
+ if (new_setting->it_value.tv_sec || new_setting->it_value.tv_nsec)
+ timer->it_interval = timespec64_to_ktime(new_setting->it_interval);
+
+ /* Prevent reloading in case there is a signal pending */
+ timer->it_requeue_pending = (timer->it_requeue_pending + 2) & ~REQUEUE_PENDING;
+ /* Reset overrun accounting */
+ timer->it_overrun_last = 0;
+ timer->it_overrun = -1LL;
+}
+
/* Set a POSIX.1b interval timer. */
int common_timer_set(struct k_itimer *timr, int flags,
struct itimerspec64 *new_setting,
@@ -875,16 +890,12 @@ int common_timer_set(struct k_itimer *ti
return TIMER_RETRY;

timr->it_active = 0;
- timr->it_requeue_pending = (timr->it_requeue_pending + 2) &
- ~REQUEUE_PENDING;
- timr->it_overrun_last = 0;
- timr->it_overrun = -1LL;
+ posix_timer_set_common(timr, new_setting);

- /* Switch off the timer when it_value is zero */
+ /* Keep timer disarmed when it_value is zero */
if (!new_setting->it_value.tv_sec && !new_setting->it_value.tv_nsec)
return 0;

- timr->it_interval = timespec64_to_ktime(new_setting->it_interval);
expires = timespec64_to_ktime(new_setting->it_value);
if (flags & TIMER_ABSTIME)
expires = timens_ktime_to_host(timr->it_clock, expires);
--- a/kernel/time/posix-timers.h
+++ b/kernel/time/posix-timers.h
@@ -42,4 +42,5 @@ void common_timer_get(struct k_itimer *t
int common_timer_set(struct k_itimer *timr, int flags,
struct itimerspec64 *new_setting,
struct itimerspec64 *old_setting);
+void posix_timer_set_common(struct k_itimer *timer, struct itimerspec64 *new_setting);
int common_timer_del(struct k_itimer *timer);



2023-07-03 21:32:25

by Frederic Weisbecker

[permalink] [raw]
Subject: Re: [patch 16/45] posix-timers: Consolidate timer setup

Le Tue, Jun 06, 2023 at 04:37:44PM +0200, Thomas Gleixner a ?crit :
> hrtimer based and CPU timers have their own way to install the new interval
> and to reset overrun and signal handling related data.
>
> Create a helper function and do the same operation for all variants.
>
> Signed-off-by: Thomas Gleixner <[email protected]>
> ---
> kernel/time/posix-cpu-timers.c | 15 +--------------
> kernel/time/posix-timers.c | 23 +++++++++++++++++------
> kernel/time/posix-timers.h | 1 +
> 3 files changed, 19 insertions(+), 20 deletions(-)
>
> --- a/kernel/time/posix-cpu-timers.c
> +++ b/kernel/time/posix-cpu-timers.c
> @@ -709,21 +709,8 @@ static int posix_cpu_timer_set(struct k_
> trigger_base_recalc_expires(timer, p);
>
> unlock_task_sighand(p, &flags);
> - /*
> - * Install the new reload setting, and
> - * set up the signal and overrun bookkeeping.
> - */
> - timer->it_interval = timespec64_to_ktime(new->it_interval);
>
> - /*
> - * This acts as a modification timestamp for the timer,
> - * so any automatic reload attempt will punt on seeing
> - * that we have reset the timer manually.
> - */
> - timer->it_requeue_pending = (timer->it_requeue_pending + 2) &
> - ~REQUEUE_PENDING;
> - timer->it_overrun_last = 0;
> - timer->it_overrun = -1;
> + posix_timer_set_common(timer, new);

So before this patch if a posix cpu timer is set with:

.it_value = 0,
.it_interval = 5

a further retrieval would return the same. But after this patch
it will return:

.it_value = 0,
.it_interval = 0

That's an ABI change, not sure if it matters though...