linux-kernel - Re: [PATCH 13/21] x86/intel_rdt/cqm: Add cpus file support

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Date:   Thu, 6 Jul 2017 14:26:09 -0700 (PDT)
From:   Shivappa Vikas <vikas.shivappa@...el.com>
To:     Thomas Gleixner <tglx@...utronix.de>
cc:     Vikas Shivappa <vikas.shivappa@...ux.intel.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org, hpa@...or.com, peterz@...radead.org,
        ravi.v.shankar@...el.com, vikas.shivappa@...el.com,
        tony.luck@...el.com, fenghua.yu@...el.com, andi.kleen@...el.com
Subject: Re: [PATCH 13/21] x86/intel_rdt/cqm: Add cpus file support



On Sun, 2 Jul 2017, Thomas Gleixner wrote:

> On Mon, 26 Jun 2017, Vikas Shivappa wrote:
>> diff --git a/arch/x86/kernel/cpu/intel_rdt.h b/arch/x86/kernel/cpu/intel_rdt.h
>> index fdf3654..fec8ba9 100644
>> --- a/arch/x86/kernel/cpu/intel_rdt.h
>> +++ b/arch/x86/kernel/cpu/intel_rdt.h
>> @@ -37,6 +37,8 @@ struct mon_evt {
>>  extern bool rdt_alloc_enabled;
>>  extern int rdt_mon_features;
>>
>> +DECLARE_PER_CPU_READ_MOSTLY(int, cpu_rmid);
>
> u32
>
>>
>> +DEFINE_PER_CPU_READ_MOSTLY(int, cpu_rmid);
>>  static inline struct rmid_entry *__rmid_entry(u32 rmid)
>
> Bah. Please add a new line between the DEFINE... and the function.
>
> But that whole thing is wrong. The per cpu default closid and rmid want to
> be in a single place, not in two distinct per cpu variables.
>
> struct rdt_cpu_default {
>       u32	rmid;
>       u32	closid;
> };
>
> DEFINE_PER_CPU_READ_MOSTLY(struct rdt_cpu_default, rdt_cpu_default);
>
> or something like this. That way it's guaranteed that the context switch
> code touches a single cache line for the per cpu defaults.

Will fix and add both rmid and closid into common struct.

Thanks,
Vikas

>
> Thanks,
>
> 	tglx
>
>