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From: Anna-Maria Behnsen <anna-maria@linutronix.de>
To: Thomas Gleixner <tglx@linutronix.de>, LKML <linux-kernel@vger.kernel.org>
Cc: Frederic Weisbecker <frederic@kernel.org>, John Stultz
 <jstultz@google.com>, Peter Zijlstra <peterz@infradead.org>, Ingo Molnar
 <mingo@kernel.org>, Stephen Boyd <sboyd@kernel.org>, Eric Biederman
 <ebiederm@xmission.com>, Oleg Nesterov <oleg@redhat.com>
Subject: Re: [patch V2 21/50] posix-cpu-timers: Make k_itimer::it_active
 consistent
In-Reply-To: <20240410165552.256162566@linutronix.de>
References: <20240410164558.316665885@linutronix.de>
 <20240410165552.256162566@linutronix.de>
Date: Wed, 17 Apr 2024 12:11:27 +0200
Message-ID: <87le5cwb74.fsf@somnus>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain

Thomas Gleixner <tglx@linutronix.de> writes:

> Posix CPU timers are not updating k_itimer::it_active which makes it
> impossible to base decisions in the common posix timer code on it.
>
> Update it when queueing or dequeueing posix CPU timers.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
> V2: Move the clearing to cpu_timer_fire() - Frederic
> ---
>  kernel/time/posix-cpu-timers.c |    4 ++++
>  1 file changed, 4 insertions(+)
>
> --- a/kernel/time/posix-cpu-timers.c
> +++ b/kernel/time/posix-cpu-timers.c
> @@ -453,6 +453,7 @@ static void disarm_timer(struct k_itimer
>  	struct cpu_timer *ctmr = &timer->it.cpu;
>  	struct posix_cputimer_base *base;
>  
> +	timer->it_active = 0;
>  	if (!cpu_timer_dequeue(ctmr))
>  		return;
>  
> @@ -559,6 +560,7 @@ static void arm_timer(struct k_itimer *t
>  	struct cpu_timer *ctmr = &timer->it.cpu;
>  	u64 newexp = cpu_timer_getexpires(ctmr);
>  
> +	timer->it_active = 1;
>  	if (!cpu_timer_enqueue(&base->tqhead, ctmr))
>  		return;
>  
> @@ -584,6 +586,7 @@ static void cpu_timer_fire(struct k_itim
>  {
>  	struct cpu_timer *ctmr = &timer->it.cpu;
>  
> +	timer->it_active = 0;
>  	if (unlikely(timer->sigq == NULL)) {
>  		/*
>  		 * This a special case for clock_nanosleep,
> @@ -668,6 +671,7 @@ static int posix_cpu_timer_set(struct k_
>  		ret = TIMER_RETRY;
>  	} else {
>  		cpu_timer_dequeue(ctmr);
> +		timer->it_active = 0;

NIT: you could change the order of the above two commands, then it is in
the same order as the others.

with or without changing the NIT:
Reviewed-by: Anna-Maria Behnsen <anna-maria@linutronix.de>