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Subject: Re: [PATCH 5/7] x86/resctrl: Add a new "snc_ways" file to the
 monitoring info directory.
Content-Language: en-GB
To: Tony Luck <tony.luck@intel.com>, Fenghua Yu <fenghua.yu@intel.com>,
 Reinette Chatre <reinette.chatre@intel.com>,
 Peter Newman <peternewman@google.com>, Jonathan Corbet <corbet@lwn.net>,
 x86@kernel.org
Cc: Shaopeng Tan <tan.shaopeng@fujitsu.com>,
 Jamie Iles <quic_jiles@quicinc.com>, Babu Moger <babu.moger@amd.com>,
 linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
 patches@lists.linux.dev
References: <20230126184157.27626-1-tony.luck@intel.com>
 <20230126184157.27626-6-tony.luck@intel.com>
From: James Morse <james.morse@arm.com>
In-Reply-To: <20230126184157.27626-6-tony.luck@intel.com>
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Hi Tony,

On 26/01/2023 18:41, Tony Luck wrote:
> Make it easy for the user to tell if Sub-NUMA Cluster is enabled by
> providing an info/ file.

I think what this is conveying to user-space is 'domain_id_is_numa_node'.

Does user-space need to know the number of ways?

Will this always be a single number, or will it ever be possible to have an SNC=2 and
SNC=1 package in the same system?


Thanks,

James

> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> index a0dc64a70d01..392e7a08d083 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -997,6 +997,14 @@ static int rdt_num_rmids_show(struct kernfs_open_file *of,
>  	return 0;
>  }
>  
> +static int rdt_snc_ways_show(struct kernfs_open_file *of,
> +			     struct seq_file *seq, void *v)
> +{
> +	seq_printf(seq, "%d\n", snc_ways);
> +
> +	return 0;
> +}
> +
>  static int rdt_mon_features_show(struct kernfs_open_file *of,
>  				 struct seq_file *seq, void *v)
>  {
> @@ -1451,6 +1459,13 @@ static struct rftype res_common_files[] = {
>  		.seq_show	= rdt_num_rmids_show,
>  		.fflags		= RF_MON_INFO,
>  	},
> +	{
> +		.name		= "snc_ways",
> +		.mode		= 0444,
> +		.kf_ops		= &rdtgroup_kf_single_ops,
> +		.seq_show	= rdt_snc_ways_show,
> +		.fflags		= RF_MON_INFO,
> +	},
>  	{
>  		.name		= "cbm_mask",
>  		.mode		= 0444,