linux-kernel - Re: [PATCH v15-RFC 1/8] x86/resctrl: Split the RDT_RESOURCE

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Date: Fri, 9 Feb 2024 13:40:57 -0600
From: "Moger, Babu" <babu.moger@....com>
To: Tony Luck <tony.luck@...el.com>
Cc: Fenghua Yu <fenghua.yu@...el.com>,
 Reinette Chatre <reinette.chatre@...el.com>,
 Peter Newman <peternewman@...gle.com>, Jonathan Corbet <corbet@....net>,
 Shuah Khan <skhan@...uxfoundation.org>, x86@...nel.org,
 Shaopeng Tan <tan.shaopeng@...itsu.com>, James Morse <james.morse@....com>,
 Jamie Iles <quic_jiles@...cinc.com>, Randy Dunlap <rdunlap@...radead.org>,
 Drew Fustini <dfustini@...libre.com>, linux-kernel@...r.kernel.org,
 linux-doc@...r.kernel.org, patches@...ts.linux.dev
Subject: Re: [PATCH v15-RFC 1/8] x86/resctrl: Split the RDT_RESOURCE_L3
 resource



On 2/9/24 12:44, Tony Luck wrote:
> On Fri, Feb 09, 2024 at 09:28:16AM -0600, Moger, Babu wrote:
>>>  enum resctrl_res_level {
>>> +	RDT_RESOURCE_L3_MON,
>>>  	RDT_RESOURCE_L3,
>>
>> How about?
>> RDT_RESOURCE_L3,
>> RDT_RESOURCE_L3_MON,
> 
> Does the order matter? I put the L3_MON one first because historically
> cache occupancy was the first resctrl tool. But if you have a better
> argument for the order, then I can change it.

That is fine. No need to change.

> 
>>>  	RDT_RESOURCE_L2,
>>>  	RDT_RESOURCE_MBA,
>>> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
>>> index aa9810a64258..c50f55d7790e 100644
>>> --- a/arch/x86/kernel/cpu/resctrl/core.c
>>> +++ b/arch/x86/kernel/cpu/resctrl/core.c
>>> @@ -60,6 +60,16 @@ mba_wrmsr_amd(struct rdt_domain *d, struct msr_param *m,
>>>  #define domain_init(id) LIST_HEAD_INIT(rdt_resources_all[id].r_resctrl.domains)
>>>  
>>>  struct rdt_hw_resource rdt_resources_all[] = {
>>> +	[RDT_RESOURCE_L3_MON] =
>>> +	{
>>> +		.r_resctrl = {
>>> +			.rid			= RDT_RESOURCE_L3_MON,
>>> +			.name			= "L3",
>>
>> L3_MON ?
> 
> That was my first choice too. But I found:
> 
> $ ls /sys/fs/resctrl/info
> L3  L3_MON_MON  last_cmd_status  MB
> 
> This would be easy to fix ... just change this code to not append
> an extra "_MON" to the directory name:
> 
>         for_each_mon_capable_rdt_resource(r) {
>                 fflags = r->fflags | RFTYPE_MON_INFO;
>                 sprintf(name, "%s_MON", r->name);
>                 ret = rdtgroup_mkdir_info_resdir(r, name, fflags);
>                 if (ret)
>                         goto out_destroy;
>         }
> 
> But I also saw this:
> $ ls /sys/fs/resctrl/mon_data/
> mon_L3_MON_00  mon_L3_MON_01
> 
> which didn't seem to have an easy fix. So I took the easy route and left
> the ".name" field as "L3_MON".
> 

Ok. Sounds good.

-- 
Thanks
Babu Moger