linux-kernel - Re: [PATCH v7 06/24] x86/resctrl: Access per-rmid structures by index

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Message-ID: <8f1c6ec9-fbd8-4fc1-eeb7-2c6badcd0065@arm.com>
Date:   Wed, 13 Dec 2023 18:04:22 +0000
From:   James Morse <james.morse@....com>
To:     Reinette Chatre <reinette.chatre@...el.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Cc:     Fenghua Yu <fenghua.yu@...el.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        H Peter Anvin <hpa@...or.com>,
        Babu Moger <Babu.Moger@....com>,
        shameerali.kolothum.thodi@...wei.com,
        D Scott Phillips OS <scott@...amperecomputing.com>,
        carl@...amperecomputing.com, lcherian@...vell.com,
        bobo.shaobowang@...wei.com, tan.shaopeng@...itsu.com,
        baolin.wang@...ux.alibaba.com, Jamie Iles <quic_jiles@...cinc.com>,
        Xin Hao <xhao@...ux.alibaba.com>, peternewman@...gle.com,
        dfustini@...libre.com, amitsinght@...vell.com
Subject: Re: [PATCH v7 06/24] x86/resctrl: Access per-rmid structures by index

Hi Reinette,

On 09/11/2023 17:42, Reinette Chatre wrote:
> On 10/25/2023 11:03 AM, James Morse wrote:
>> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
>> index 0056c9962a44..fc70a2650729 100644
>> --- a/arch/x86/kernel/cpu/resctrl/core.c
>> +++ b/arch/x86/kernel/cpu/resctrl/core.c
>> @@ -604,7 +604,8 @@ static void clear_closid_rmid(int cpu)
>>  	state->default_rmid = 0;
>>  	state->cur_closid = 0;
>>  	state->cur_rmid = 0;
> 
> These assignments can also use the new RESERVED defines, no?

Yup, done.

>> -	wrmsr(MSR_IA32_PQR_ASSOC, 0, 0);
>> +	wrmsr(MSR_IA32_PQR_ASSOC, RESCTRL_RESERVED_RMID,
>> +	      RESCTRL_RESERVED_CLOSID);
>>  }
>>  
> 
> 
> Looks like rdtgroup_setup_default() is also a candidate to replace
> hardcoded "0" for closid and rmid with the new defines.

Sure, done.


>> @@ -670,7 +703,7 @@ void cqm_handle_limbo(struct work_struct *work)
>>  
>>  	__check_limbo(d, false);
>>  
>> -	if (has_busy_rmid(r, d))
>> +	if (has_busy_rmid(d))
>>  		schedule_delayed_work_on(cpu, &d->cqm_limbo, delay);
>>  
> 
> This change results in a new compile warning:
> 
> arch/x86/kernel/cpu/resctrl/monitor.c: In function ‘cqm_handle_limbo’:
> arch/x86/kernel/cpu/resctrl/monitor.c:805:30: warning: variable ‘r’ set but not used [-Wunused-but-set-variable]
>   805 |         struct rdt_resource *r; 

Hmm, looks like the assignment foxes gcc-12 into thinking this is okay.
I've removed that now.


Thanks,

James