Re: [PATCH v9 9/9] x86/resctrl: Display RMID of resource group

[Fenghua Yu]

Hi, Babu,

On 9/7/23 16:51, Babu Moger wrote:
> In x86, hardware uses RMID to identify a a monitoring group. When a

s/a a/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.
>
> Add the flag RFTYPE_MON_BASE, which contains the files required only
> for the MON group.
>
> For example:
>   $cat /sys/fs/resctrl/mon_groups/mon_grp1/mon_hw_id
>   3
>
> Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
> ---
>   Documentation/arch/x86/resctrl.rst     |  4 +++
>   arch/x86/kernel/cpu/resctrl/internal.h |  6 ++++
>   arch/x86/kernel/cpu/resctrl/rdtgroup.c | 38 +++++++++++++++++++++++---
>   3 files changed, 44 insertions(+), 4 deletions(-)
>
> 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 ccdbed615d41..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
>    *
> @@ -315,6 +320,7 @@ struct rdtgroup {
>   #define RFTYPE_MON_INFO			(RFTYPE_INFO | RFTYPE_MON)
>   #define RFTYPE_TOP_INFO			(RFTYPE_INFO | RFTYPE_TOP)
>   #define RFTYPE_CTRL_BASE		(RFTYPE_BASE | RFTYPE_CTRL)
> +#define RFTYPE_MON_BASE			(RFTYPE_BASE | RFTYPE_MON)
>   
>   /* List of all resource groups */
>   extern struct list_head rdt_all_groups;
> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> index 8be0fb323ad3..fc830ffce82a 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,

Similar to showing ctrl_hw_id, is it better to rename 
"rdtgroup_rmid_show" as "rdtgroup_mon_hw_id_show" for arch neutral naming?

> +		.fflags		= RFTYPE_MON_BASE | RFTYPE_DEBUG,
> +	},
>   	{
>   		.name		= "schemata",
>   		.mode		= 0644,
> @@ -2535,6 +2558,7 @@ static void schemata_list_destroy(void)
>   static int rdt_get_tree(struct fs_context *fc)
>   {
>   	struct rdt_fs_context *ctx = rdt_fc2context(fc);
> +	unsigned long flags = RFTYPE_CTRL_BASE;
>   	struct rdt_domain *dom;
>   	struct rdt_resource *r;
>   	int ret;
> @@ -2565,7 +2589,10 @@ static int rdt_get_tree(struct fs_context *fc)
>   
>   	closid_init();
>   
> -	ret = rdtgroup_add_files(rdtgroup_default.kn, RFTYPE_CTRL_BASE);
> +	if (rdt_mon_capable)
> +		flags |= RFTYPE_MON;
> +
> +	ret = rdtgroup_add_files(rdtgroup_default.kn, flags);
>   	if (ret)
>   		goto out_schemata_free;
>   
> @@ -3255,8 +3282,8 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
>   			     enum rdt_group_type rtype, struct rdtgroup **r)
>   {
>   	struct rdtgroup *prdtgrp, *rdtgrp;
> +	unsigned long files = 0;
>   	struct kernfs_node *kn;
> -	uint files = 0;
>   	int ret;
>   
>   	prdtgrp = rdtgroup_kn_lock_live(parent_kn);
> @@ -3308,10 +3335,13 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
>   		goto out_destroy;
>   	}
>   
> -	if (rtype == RDTCTRL_GROUP)
> +	if (rtype == RDTCTRL_GROUP) {
>   		files = RFTYPE_BASE | RFTYPE_CTRL;
> -	else
> +		if (rdt_mon_capable)
> +			files |= RFTYPE_MON;
> +	} else {
>   		files = RFTYPE_BASE | RFTYPE_MON;
> +	}
>   
>   	ret = rdtgroup_add_files(kn, files);
>   	if (ret) {

Thanks.

-Fenghua