linux-kernel - Re: [PATCH v2 8/8] x86/vdso: Move out the CPU number store

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Date:   Wed, 6 Jun 2018 22:59:53 +0000
From:   "Bae, Chang Seok" <chang.seok.bae@...el.com>
To:     Andy Lutomirski <luto@...nel.org>
CC:     "H. Peter Anvin" <hpa@...or.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>,
        Andi Kleen <ak@...ux.intel.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "Metzger, Markus T" <markus.t.metzger@...el.com>,
        "Shankar, Ravi V" <ravi.v.shankar@...el.com>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 8/8] x86/vdso: Move out the CPU number store

> On Wed, Jun 6, 2018 at 10:25 AM Andy Lutomirski <luto@...nel.org> wrote:
>> On Wed, Jun 6, 2018 at 9:23 AM Chang S. Bae <chang.seok.bae@...el.com> wrote:
>> +static inline void setup_cpu_number_segment(int cpu)
>> +{
>> +#ifdef CONFIG_NUMA
>> +       unsigned long node = early_cpu_to_node(cpu);
>> +#else
>> +       unsigned long node = 0;
>> +#endif
> This duplicates half the rdtscp_aux code.  How about making this one
> function setup_cpu_number() that does all of it?
Looks like the segment setup done during early boot (single-threaded).
So, separating MSR TSC_AUX setup out to each CPU initialization seems
to be still reasonable to me.

Thanks,
Chang