linux-kernel - Re: [patch V3 26/60] x86/apic/32: Decrapify the def

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Message-ID: <09100858-3be2-a9f2-e0af-b6cad67d760b@intel.com>
Date:   Mon, 7 Aug 2023 13:11:43 -0700
From:   Dave Hansen <dave.hansen@...el.com>
To:     Thomas Gleixner <tglx@...utronix.de>,
        LKML <linux-kernel@...r.kernel.org>
Cc:     x86@...nel.org, Andrew Cooper <andrew.cooper3@...rix.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Wei Liu <wei.liu@...nel.org>,
        Arjan van de Ven <arjan@...ux.intel.com>,
        Juergen Gross <jgross@...e.com>,
        Michael Kelley <mikelley@...rosoft.com>,
        Peter Keresztes Schmidt <peter@...esztesschmidt.de>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>
Subject: Re: [patch V3 26/60] x86/apic/32: Decrapify the def_bigsmp mechanism

On 8/1/23 03:47, Thomas Gleixner wrote:
...
> -void __init default_setup_apic_routing(void)
> +void __init x86_32_probe_bigsmp_early(void)
>  {
> -	int version = boot_cpu_apic_version;
> +	if (nr_cpu_ids <= 8 || xen_pv_domain())
> +		return;
...
> +void __init default_setup_apic_routing(void)
> +{
> +	if (nr_cpu_ids >= 8 && !xen_pv_domain())
> +		apic_bigsmp_force();

I thought bigsmp didn't come into play until 9 or more CPUs.  Won't this
do apic_bigsmp_force() at nr_cpu_ids==8?

Should this be:

	if (nr_cpu_ids > 8 && !xen_pv_domain())
		apic_bigsmp_force();

?