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

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Date:   Tue, 15 Aug 2023 15:52:17 -0700
From:   Reinette Chatre <reinette.chatre@...el.com>
To:     Babu Moger <babu.moger@....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 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"

> 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.

Apart from that this patch looks good to me.

Reinette