linux-kernel - Re: [PATCH v10 10/10] x86/resctrl: Display RMID of resource group

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Date:   Fri, 29 Sep 2023 18:56:37 +0300 (EEST)
From:   Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To:     Babu Moger <babu.moger@....com>
cc:     corbet@....net, Reinette Chatre <reinette.chatre@...el.com>,
        tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
        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, LKML <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 v10 10/10] x86/resctrl: Display RMID of resource group

On Fri, 15 Sep 2023, Babu Moger wrote:

> In x86, hardware uses RMID to identify a monitoring group. When a user
> creates a monitor group these details are not visible. These details
> can help resctrl debugging.
> 
> Add RMID(mon_hw_id) to the monitor groups display in resctrl interface.
> Users can see these details when resctrl is mounted with "-o debug" option.
> 
> Other architectures do not use "RMID". Use the name mon_hw_id to refer
> to "RMID" in an effort to keep the naming generic.
> 
> For example:
>  $cat /sys/fs/resctrl/mon_groups/mon_grp1/mon_hw_id
>  3
> 
> Signed-off-by: Babu Moger <babu.moger@....com>
> ---
>  Documentation/arch/x86/resctrl.rst     |  4 ++++
>  arch/x86/kernel/cpu/resctrl/internal.h |  5 +++++
>  arch/x86/kernel/cpu/resctrl/rdtgroup.c | 23 +++++++++++++++++++++++
>  3 files changed, 32 insertions(+)
> 
> diff --git a/Documentation/arch/x86/resctrl.rst b/Documentation/arch/x86/resctrl.rst
> index 54691c8b832d..98b0eb509ed4 100644
> --- a/Documentation/arch/x86/resctrl.rst
> +++ b/Documentation/arch/x86/resctrl.rst
> @@ -369,6 +369,10 @@ 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/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
> index a07fa4329b65..b4910892b0a6 100644
> --- a/arch/x86/kernel/cpu/resctrl/internal.h
> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
> @@ -296,6 +296,11 @@ struct rdtgroup {
>   *	--> RFTYPE_BASE (Files common for both MON and CTRL groups)
>   *	    Files: cpus, cpus_list, tasks
>   *
> + *		--> RFTYPE_MON (Files only for MON group)
> + *
> + *			--> RFTYPE_DEBUG (Files to help resctrl debugging)
> + *			    File: mon_hw_id
> + *
>   *		--> RFTYPE_CTRL (Files only for CTRL group)
>   *		    Files: mode, schemata, size
>   *
> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> index 55d1b90f460e..ef4b18091e5d 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -795,6 +795,22 @@ static int rdtgroup_closid_show(struct kernfs_open_file *of,
>  	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
>  
>  /*
> @@ -1856,6 +1872,13 @@ 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_MON_BASE | RFTYPE_DEBUG,
> +	},
>  	{
>  		.name		= "schemata",
>  		.mode		= 0644,
> 

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>


-- 
 i.