linux-kernel - Re: [PATCH V2 1/4] x86/resctrl: Use IPI instead of task_work_add() to update PQR

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Message-ID: <20210106111958.GD5729@zn.tnic>
Date:   Wed, 6 Jan 2021 12:19:58 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Reinette Chatre <reinette.chatre@...el.com>
Cc:     tglx@...utronix.de, fenghua.yu@...el.com, tony.luck@...el.com,
        kuo-lang.tseng@...el.com, shakeelb@...gle.com,
        valentin.schneider@....com, mingo@...hat.com, babu.moger@....com,
        james.morse@....com, hpa@...or.com, x86@...nel.org,
        linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH V2 1/4] x86/resctrl: Use IPI instead of task_work_add()
 to update PQR_ASSOC MSR

On Thu, Dec 17, 2020 at 02:31:18PM -0800, Reinette Chatre wrote:
> +#ifdef CONFIG_SMP
> +static void update_task_closid_rmid(struct task_struct *t)
> +{
> +	if (task_curr(t))
> +		smp_call_function_single(task_cpu(t), _update_task_closid_rmid,
> +					 t, 1);
>  }
> +#else
> +static void update_task_closid_rmid(struct task_struct *t)
> +{
> +	_update_task_closid_rmid(t);
> +}
> +#endif

Why the ifdeffery? Why not simply:

static void update_task_closid_rmid(struct task_struct *t)
{
        if (IS_ENABLED(CONFIG_SMP) && task_curr(t))
                smp_call_function_single(task_cpu(t), _update_task_closid_rmid, t, 1);
        else
                _update_task_closid_rmid(t);
}

?

If no particular reason, I'll change it before committing.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette