linux-kernel - Re: [PATCH v12 21/31] fs/resctrl: Refactor rmdir_mondata_subdir

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Message-ID: <3f02a7a8-9996-43e0-9f86-7d685f64f965@intel.com>
Date: Thu, 23 Oct 2025 10:45:35 -0700
From: Reinette Chatre <reinette.chatre@...el.com>
To: Tony Luck <tony.luck@...el.com>, Fenghua Yu <fenghuay@...dia.com>, "Maciej
 Wieczor-Retman" <maciej.wieczor-retman@...el.com>, Peter Newman
	<peternewman@...gle.com>, James Morse <james.morse@....com>, Babu Moger
	<babu.moger@....com>, Drew Fustini <dfustini@...libre.com>, Dave Martin
	<Dave.Martin@....com>, Chen Yu <yu.c.chen@...el.com>
CC: <x86@...nel.org>, <linux-kernel@...r.kernel.org>,
	<patches@...ts.linux.dev>
Subject: Re: [PATCH v12 21/31] fs/resctrl: Refactor
 rmdir_mondata_subdir_allrdtgrp()

Hi Tony,

On 10/13/25 3:33 PM, Tony Luck wrote:
> rmdir_mondata_subdir_allrdtgrp() is complicated because of the support for
> Sub-NUMA Cluster (SNC) mode.

"rmdir_mondata_subdir_allrdtgrp()" -> "Clearing a monitor group's mon_data directory"?

> 
> Refactor into a helper function for the SNC case to make it easier to add support

"Refactor into a helper function for the SNC case" -> "Refactor the SNC case into a helper function"?

> for a new telemetry resource.
> 
> Suggested-by: Reinette Chatre <reinette.chatre@...el.com>
> Signed-off-by: Tony Luck <tony.luck@...el.com>
> ---
>  fs/resctrl/rdtgroup.c | 41 +++++++++++++++++++++++++++++------------
>  1 file changed, 29 insertions(+), 12 deletions(-)
> 
> diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
> index b7eaa4388768..837279d97db4 100644
> --- a/fs/resctrl/rdtgroup.c
> +++ b/fs/resctrl/rdtgroup.c
> @@ -3162,6 +3162,29 @@ static void mon_rmdir_one_subdir(struct kernfs_node *pkn, char *name, char *subn
>  		kernfs_remove_by_name(kn, subname);
>  }
>  
> +static void rmdir_mondata_subdir_allrdtgrp_snc(struct rdt_resource *r,
> +					       struct rdt_domain_hdr *hdr)
> +{
> +	struct rdtgroup *prgrp, *crgrp;
> +	struct rdt_l3_mon_domain *d;
> +	char subname[32];
> +	char name[32];
> +
> +	if (!domain_header_is_valid(hdr, RESCTRL_MON_DOMAIN, RDT_RESOURCE_L3))
> +		return;
> +
> +	d = container_of(hdr, struct rdt_l3_mon_domain, hdr);
> +	sprintf(name, "mon_%s_%02d", r->name, d->ci_id);
> +	sprintf(subname, "mon_sub_%s_%02d", r->name, hdr->id);
> +
> +	list_for_each_entry(prgrp, &rdt_all_groups, rdtgroup_list) {
> +		mon_rmdir_one_subdir(prgrp->mon.mon_data_kn, name, subname);
> +
> +		list_for_each_entry(crgrp, &prgrp->mon.crdtgrp_list, mon.crdtgrp_list)
> +			mon_rmdir_one_subdir(crgrp->mon.mon_data_kn, name, subname);
> +	}
> +}
> +
>  /*
>   * Remove all subdirectories of mon_data of ctrl_mon groups
>   * and monitor groups for the given domain.
> @@ -3172,25 +3195,19 @@ static void rmdir_mondata_subdir_allrdtgrp(struct rdt_resource *r,
>  					   struct rdt_domain_hdr *hdr)

This function's comments still mentions the actions needed to support SNC. Can this be
moved with the code?

>  {
>  	struct rdtgroup *prgrp, *crgrp;
> -	struct rdt_l3_mon_domain *d;
> -	char subname[32];
> -	bool snc_mode;
>  	char name[32];
>  
> -	if (!domain_header_is_valid(hdr, RESCTRL_MON_DOMAIN, RDT_RESOURCE_L3))
> +	if (r->mon_scope == RESCTRL_L3_NODE) {

https://lore.kernel.org/lkml/aOhd_A5L8PV0OYba@agluck-desk3/

> +		rmdir_mondata_subdir_allrdtgrp_snc(r, hdr);
>  		return;
> +	}
>  
> -	d = container_of(hdr, struct rdt_l3_mon_domain, hdr);
> -	snc_mode = r->mon_scope == RESCTRL_L3_NODE;
> -	sprintf(name, "mon_%s_%02d", r->name, snc_mode ? d->ci_id : d->hdr.id);
> -	if (snc_mode)
> -		sprintf(subname, "mon_sub_%s_%02d", r->name, d->hdr.id);
> -
> +	sprintf(name, "mon_%s_%02d", r->name, hdr->id);
>  	list_for_each_entry(prgrp, &rdt_all_groups, rdtgroup_list) {
> -		mon_rmdir_one_subdir(prgrp->mon.mon_data_kn, name, subname);
> +		kernfs_remove_by_name(prgrp->mon.mon_data_kn, name);
>  
>  		list_for_each_entry(crgrp, &prgrp->mon.crdtgrp_list, mon.crdtgrp_list)
> -			mon_rmdir_one_subdir(crgrp->mon.mon_data_kn, name, subname);
> +			kernfs_remove_by_name(crgrp->mon.mon_data_kn, name);
>  	}
>  }
>  

Reinette