linux-kernel - Re: [PATCH v7 16/24] x86/resctrl: Add the interface to assign/update counter assignment

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Message-ID: <f3edc43a-886f-47a2-bde4-1acc0c0dcc88@intel.com>
Date: Thu, 26 Sep 2024 18:48:14 -0700
From: Reinette Chatre <reinette.chatre@...el.com>
To: <babu.moger@....com>, <corbet@....net>, <fenghua.yu@...el.com>,
	<tglx@...utronix.de>, <mingo@...hat.com>, <bp@...en8.de>,
	<dave.hansen@...ux.intel.com>
CC: <x86@...nel.org>, <hpa@...or.com>, <paulmck@...nel.org>,
	<rdunlap@...radead.org>, <tj@...nel.org>, <peterz@...radead.org>,
	<yanjiewtw@...il.com>, <kim.phillips@....com>, <lukas.bulwahn@...il.com>,
	<seanjc@...gle.com>, <jmattson@...gle.com>, <leitao@...ian.org>,
	<jpoimboe@...nel.org>, <rick.p.edgecombe@...el.com>,
	<kirill.shutemov@...ux.intel.com>, <jithu.joseph@...el.com>,
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	<daniel.sneddon@...ux.intel.com>, <pbonzini@...hat.com>,
	<sandipan.das@....com>, <ilpo.jarvinen@...ux.intel.com>,
	<peternewman@...gle.com>, <maciej.wieczor-retman@...el.com>,
	<linux-doc@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<eranian@...gle.com>, <james.morse@....com>
Subject: Re: [PATCH v7 16/24] x86/resctrl: Add the interface to assign/update
 counter assignment

Hi Babu,

On 9/26/24 9:59 AM, Moger, Babu wrote:
> On 9/26/24 11:46, Reinette Chatre wrote:
>> On 9/26/24 9:28 AM, Moger, Babu wrote:
>>> On 9/19/24 12:20, Reinette Chatre wrote:
>>>> On 9/4/24 3:21 PM, Babu Moger wrote:
>>>>> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>>>>> index 7ad653b4e768..1d45120ff2b5 100644
>>>>> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>>>>> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>>>>> @@ -864,6 +864,13 @@ static int rdtgroup_rmid_show(struct kernfs_open_file *of,
>>>>>  	return ret;
>>>>>  }
>>>>>  
>>>>> +/*
>>>>> + * Get the counter index for the assignable counter
>>>>> + * 0 for evtid == QOS_L3_MBM_TOTAL_EVENT_ID
>>>>> + * 1 for evtid == QOS_L3_MBM_LOCAL_EVENT_ID
>>>>> + */
>>>>> +#define MBM_EVENT_ARRAY_INDEX(_event) ((_event) - 2)
>>>>> +
>>>>>  static int rdtgroup_mbm_assign_mode_show(struct kernfs_open_file *of,
>>>>>  					 struct seq_file *s, void *v)
>>>>>  {
>>>>> @@ -1898,6 +1905,45 @@ int resctrl_arch_assign_cntr(struct rdt_resource *r, struct rdt_mon_domain *d,
>>>>>  	return 0;
>>>>>  }
>>>>>  
>>>>> +/*
>>>>> + * Assign a hardware counter to the group.
>>>>> + * Counter will be assigned to all the domains if rdt_mon_domain is NULL
>>>>> + * else the counter will be allocated to specific domain.
>>>>> + */
>>>>> +int rdtgroup_assign_cntr(struct rdt_resource *r, struct rdtgroup *rdtgrp,
>>>>> +			 struct rdt_mon_domain *d, enum resctrl_event_id evtid)
>>>>
>>>> Could we please review the naming of function as this series progresses? Using such a generic
>>>> name for this specific function seems to result in its callers later in series having even more
>>>> generic names that are hard to decipher. For example, later (very generic) "rdtgroup_assign_grp()"
>>>> calls this function and I find rdtgroup_assign_grp() to be very vague making the code more difficult
>>>> to follow. For example, rdtgroup_assign_cntr() could be rdtgroup_assign_cntr_event() and
>>>> rdtgroup_assign_grp() could instead be rdtgroup_assign_cntr()?  Please feel free to improve.
>>>
>>> Sure.
>>>
>>> How about rdtgroup_assign_cntr_event() and rdtgroup_assign_cntr_grp() ?
>>>
>>> Added grp extension for the second one.
>>
>> Is the "grp" extension needed? The function already has "rdtgroup_" as prefix so
>> the "grp" extension does not seem necessary to me since I think "rdtgroup_" and "grp"
>> intend to refer to the same?
> 
> How about rdtgroup_assign_cntrs() ?  Added 's' in the end.
> 
> We are assigning multiple counters here.
> 

rdtgroup_assign_cntrs() sounds good to me.

Thank you

Reinette