linux-kernel - Re: [PATCH 3/4] RISC-V: Remove per cpu clocksource

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Message-ID: <mhng-a0437cab-9a27-45a5-aabe-0dee2c1d96db@palmer-si-x1c4>
Date:   Fri, 07 Dec 2018 09:00:07 -0800 (PST)
From:   Palmer Dabbelt <palmer@...ive.com>
To:     atish.patra@....com
CC:     linux-kernel@...r.kernel.org, atish.patra@....com,
        aou@...s.berkeley.edu, daniel.lezcano@...aro.org,
        devicetree@...r.kernel.org, dmitriy@...-tech.org,
        linux-riscv@...ts.infradead.org, mark.rutland@....com,
        robh+dt@...nel.org, tglx@...utronix.de, anup@...infault.org,
        Damien.LeMoal@....com
Subject:     Re: [PATCH 3/4] RISC-V: Remove per cpu clocksource

On Mon, 03 Dec 2018 12:57:30 PST (-0800), atish.patra@....com wrote:
> There is only one clocksource in RISC-V. The boot cpu initializes
> that clocksource. No need to keep a percpu data structure.
>
> Signed-off-by: Atish Patra <atish.patra@....com>
> ---
>  drivers/clocksource/riscv_timer.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/clocksource/riscv_timer.c b/drivers/clocksource/riscv_timer.c
> index 96af7058..39de6e49 100644
> --- a/drivers/clocksource/riscv_timer.c
> +++ b/drivers/clocksource/riscv_timer.c
> @@ -49,7 +49,7 @@ static unsigned long long riscv_clocksource_rdtime(struct clocksource *cs)
>  	return get_cycles64();
>  }
>
> -static DEFINE_PER_CPU(struct clocksource, riscv_clocksource) = {
> +static struct clocksource riscv_clocksource = {
>  	.name		= "riscv_clocksource",
>  	.rating		= 300,
>  	.mask		= CLOCKSOURCE_MASK(BITS_PER_LONG),
> @@ -106,7 +106,6 @@ static long __init riscv_timebase_frequency(struct device_node *node)
>  static int __init riscv_timer_init_dt(struct device_node *n)
>  {
>  	int cpuid, hartid, error;
> -	struct clocksource *cs;
>
>  	hartid = riscv_of_processor_hartid(n);
>  	cpuid = riscv_hartid_to_cpuid(hartid);
> @@ -116,8 +115,7 @@ static int __init riscv_timer_init_dt(struct device_node *n)
>
>  	/* This should be called only for boot cpu */
>  	riscv_timebase = riscv_timebase_frequency(n);
> -	cs = per_cpu_ptr(&riscv_clocksource, cpuid);
> -	clocksource_register_hz(cs, riscv_timebase);
> +	clocksource_register_hz(&riscv_clocksource, riscv_timebase);
>
>  	error = cpuhp_setup_state(CPUHP_AP_RISCV_TIMER_STARTING,
>  			 "clockevents/riscv/timer:starting",

Reviewed-by: Palmer Dabbelt <palmer@...ive.com>