linux-kernel - Re: [PATCH 2/2] clocksource: timer-imx-sysctr: set cpumask to cpu_possible

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Date:   Thu, 2 Dec 2021 11:22:13 +0100
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     "Peng Fan (OSS)" <peng.fan@....nxp.com>, tglx@...utronix.de,
        shawnguo@...nel.org, s.hauer@...gutronix.de
Cc:     kernel@...gutronix.de, festevam@...il.com, linux-imx@....com,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        van.freenix@...il.com, Peng Fan <peng.fan@....com>
Subject: Re: [PATCH 2/2] clocksource: timer-imx-sysctr: set cpumask to
 cpu_possible_mask

On 01/12/2021 13:50, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@....com>
> 
> Actually we have CLOCK_EVT_FEAT_DYNIRQ, the irq affinity will be runtime
> changed and no issue. But the system counter timer is not tied to CPU0,
> so use cpu_possible_mask here.

Did you mean:

"There is no reason to tie the system counter timer to CPU0, change its
affinity to cpu_possible_mask.

Moreover, the timer has the flag CLOCK_EVT_FEAT_DYNIRQ set, changing to
cpu_possibl_mask will reduce the number of wakeups related to the system
timer"

?

Note you may want to explain why 'there is no reason'


> Signed-off-by: Peng Fan <peng.fan@....com>
> ---
>  drivers/clocksource/timer-imx-sysctr.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/clocksource/timer-imx-sysctr.c b/drivers/clocksource/timer-imx-sysctr.c
> index 2b309af11266..55a8e198d2a1 100644
> --- a/drivers/clocksource/timer-imx-sysctr.c
> +++ b/drivers/clocksource/timer-imx-sysctr.c
> @@ -119,7 +119,7 @@ static struct timer_of to_sysctr = {
>  
>  static void __init sysctr_clockevent_init(void)
>  {
> -	to_sysctr.clkevt.cpumask = cpumask_of(0);
> +	to_sysctr.clkevt.cpumask = cpu_possible_mask;
>  
>  	clockevents_config_and_register(&to_sysctr.clkevt,
>  					timer_of_rate(&to_sysctr),
> 


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