linux-kernel - Re: [PATCH v7 8/8] x86/resctrl: Display hardware ids of resource groups

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Date:   Thu, 17 Aug 2023 14:24:10 -0500
From:   "Moger, Babu" <babu.moger@....com>
To:     Reinette Chatre <reinette.chatre@...el.com>, corbet@....net,
        tglx@...utronix.de, mingo@...hat.com, bp@...en8.de
Cc:     fenghua.yu@...el.com, dave.hansen@...ux.intel.com, x86@...nel.org,
        hpa@...or.com, paulmck@...nel.org, akpm@...ux-foundation.org,
        quic_neeraju@...cinc.com, rdunlap@...radead.org,
        damien.lemoal@...nsource.wdc.com, songmuchun@...edance.com,
        peterz@...radead.org, jpoimboe@...nel.org, pbonzini@...hat.com,
        chang.seok.bae@...el.com, pawan.kumar.gupta@...ux.intel.com,
        jmattson@...gle.com, daniel.sneddon@...ux.intel.com,
        sandipan.das@....com, tony.luck@...el.com, james.morse@....com,
        linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
        bagasdotme@...il.com, eranian@...gle.com,
        christophe.leroy@...roup.eu, jarkko@...nel.org,
        adrian.hunter@...el.com, quic_jiles@...cinc.com,
        peternewman@...gle.com
Subject: Re: [PATCH v7 8/8] x86/resctrl: Display hardware ids of resource
 groups

Hi Reinette,

On 8/15/23 17:52, Reinette Chatre wrote:
> Hi Babu,
> 
> On 8/11/2023 1:10 PM, Babu Moger wrote:
>> In x86, hardware uses CLOSID and an RMID to identify a control group and
>> a monitoring group respectively. When a user creates a control or monitor
>> group these details are not visible to the user. These details can help
>> debugging.
>>
>> Add CLOSID(ctrl_hw_id) and RMID(mon_hw_id) to the control/monitor groups
>> display in resctrl interface. Users can see these details when resctrl
>> is mounted with "-o debug" option.
>>
>> Other architectures do not use "CLOSID" and "RMID". Use the names
>> ctrl_hw_id and mon_hw_id to refer "CLOSID" and "RMID" respectively in an
> 
> "to refer" -> "to refer to"

Sure.

> 
>> effort to keep the naming generic.
>>
>> For example:
>>  $cat /sys/fs/resctrl/ctrl_grp1/ctrl_hw_id
>>  1
>>  $cat /sys/fs/resctrl/mon_groups/mon_grp1/mon_hw_id
>>  3
>>
>> Reviewed-by: Shaopeng Tan <tan.shaopeng@...fujitsu.com>
>> Tested-by: Shaopeng Tan <tan.shaopeng@...fujitsu.com>
>> Signed-off-by: Babu Moger <babu.moger@....com>
>> ---
>>  Documentation/arch/x86/resctrl.rst     |    8 ++++++
>>  arch/x86/kernel/cpu/resctrl/rdtgroup.c |   46 ++++++++++++++++++++++++++++++++
>>  2 files changed, 54 insertions(+)
>>
>> diff --git a/Documentation/arch/x86/resctrl.rst b/Documentation/arch/x86/resctrl.rst
>> index 5a2346d2c561..41ad9b1f0c6a 100644
>> --- a/Documentation/arch/x86/resctrl.rst
>> +++ b/Documentation/arch/x86/resctrl.rst
>> @@ -351,6 +351,10 @@ When control is enabled all CTRL_MON groups will also contain:
>>  	file. On successful pseudo-locked region creation the mode will
>>  	automatically change to "pseudo-locked".
>>  
>> +"ctrl_hw_id":
>> +	Available only with debug option. The identifier used by hardware
>> +	for the control group. On x86 this is the CLOSID.
>> +
>>  When monitoring is enabled all MON groups will also contain:
>>  
>>  "mon_data":
>> @@ -364,6 +368,10 @@ When monitoring is enabled all MON groups will also contain:
>>  	the sum for all tasks in the CTRL_MON group and all tasks in
>>  	MON groups. Please see example section for more details on usage.
>>  
>> +"mon_hw_id":
>> +	Available only with debug option. The identifier used by hardware
>> +	for the monitor group. On x86 this is the RMID.
>> +
>>  Resource allocation rules
>>  -------------------------
>>  
>> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> index 6b7e914657fa..94471ad9d905 100644
>> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> @@ -776,6 +776,38 @@ static int rdtgroup_tasks_show(struct kernfs_open_file *of,
>>  	return ret;
>>  }
>>  
>> +static int rdtgroup_closid_show(struct kernfs_open_file *of,
>> +				struct seq_file *s, void *v)
>> +{
>> +	struct rdtgroup *rdtgrp;
>> +	int ret = 0;
>> +
>> +	rdtgrp = rdtgroup_kn_lock_live(of->kn);
>> +	if (rdtgrp)
>> +		seq_printf(s, "%u\n", rdtgrp->closid);
>> +	else
>> +		ret = -ENOENT;
>> +	rdtgroup_kn_unlock(of->kn);
>> +
>> +	return ret;
>> +}
>> +
>> +static int rdtgroup_rmid_show(struct kernfs_open_file *of,
>> +			      struct seq_file *s, void *v)
>> +{
>> +	struct rdtgroup *rdtgrp;
>> +	int ret = 0;
>> +
>> +	rdtgrp = rdtgroup_kn_lock_live(of->kn);
>> +	if (rdtgrp)
>> +		seq_printf(s, "%u\n", rdtgrp->mon.rmid);
>> +	else
>> +		ret = -ENOENT;
>> +	rdtgroup_kn_unlock(of->kn);
>> +
>> +	return ret;
>> +}
>> +
>>  #ifdef CONFIG_PROC_CPU_RESCTRL
>>  
>>  /*
>> @@ -1837,6 +1869,13 @@ static struct rftype res_common_files[] = {
>>  		.seq_show	= rdtgroup_tasks_show,
>>  		.fflags		= RFTYPE_BASE,
>>  	},
>> +	{
>> +		.name		= "mon_hw_id",
>> +		.mode		= 0444,
>> +		.kf_ops		= &rdtgroup_kf_single_ops,
>> +		.seq_show	= rdtgroup_rmid_show,
>> +		.fflags		= RFTYPE_BASE | RFTYPE_DEBUG,
>> +	},
>>  	{
>>  		.name		= "schemata",
>>  		.mode		= 0644,
>> @@ -1860,6 +1899,13 @@ static struct rftype res_common_files[] = {
>>  		.seq_show	= rdtgroup_size_show,
>>  		.fflags		= RFTYPE_CTRL_BASE,
>>  	},
>> +	{
>> +		.name		= "ctrl_hw_id",
>> +		.mode		= 0444,
>> +		.kf_ops		= &rdtgroup_kf_single_ops,
>> +		.seq_show	= rdtgroup_closid_show,
>> +		.fflags		= RFTYPE_CTRL_BASE | RFTYPE_DEBUG,
>> +	},
>>  
>>  };
>>  
>>
>>
> 
> I think the comments introduced in patch #4 may need to be updated
> in this patch.

Sure. Will add it.
> 
> Apart from that this patch looks good to me.
> Thanks
Babu Moger