linux-kernel - Re: [PATCH 07/24] x86/resctrl: Label the resources with their configuration type

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Message-ID: <2de84538-9741-c902-9be0-5b279bbe162f@intel.com>
Date:   Tue, 17 Nov 2020 14:30:12 -0800
From:   Reinette Chatre <reinette.chatre@...el.com>
To:     James Morse <james.morse@....com>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Cc:     Fenghua Yu <fenghua.yu@...el.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        shameerali.kolothum.thodi@...wei.com,
        Jamie Iles <jamie@...iainc.com>,
        D Scott Phillips OS <scott@...amperecomputing.com>
Subject: Re: [PATCH 07/24] x86/resctrl: Label the resources with their
 configuration type

Hi James,

On 10/30/2020 9:11 AM, James Morse wrote:
> Before the name for the schema can be generated, the type of the
> configuration being applied to the resource needs to be known. Label
> all the entries in rdt_resources_all[], and copy that value in to struct

s/in to/into/ or s/in to/to/ ?

> resctrl_schema.
> 

This commit message does not explain why it is needed to copy this value.

> Subsequent patches will generate the schema names in what will become
> the fs code. Eventually the fs code will generate pairs of CODE/DATA if
> the platform supports CDP for this resource.

Explaining how the copy is a step towards accomplishing this goal would 
be very helpful.

> 
> Signed-off-by: James Morse <james.morse@....com>
> ---
>   arch/x86/kernel/cpu/resctrl/core.c     | 7 +++++++
>   arch/x86/kernel/cpu/resctrl/internal.h | 1 +
>   arch/x86/kernel/cpu/resctrl/rdtgroup.c | 1 +
>   include/linux/resctrl.h                | 8 ++++++++
>   4 files changed, 17 insertions(+)
> 


> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
> index 682e84aebd14..6c87a81946b1 100644
> --- a/arch/x86/kernel/cpu/resctrl/internal.h
> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
> @@ -367,6 +367,7 @@ struct rdt_parse_data {
>    * @mon_scale:		cqm counter * mon_scale = occupancy in bytes
>    */
>   struct rdt_hw_resource {
> +	enum resctrl_conf_type	conf_type;
>   	struct rdt_resource     resctrl;
>   

Missing an accompanying kernel-doc entry?

>   	int			num_closid;
> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> index 1bd785b1920c..628e5eb4d7a9 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -2141,6 +2141,7 @@ static int create_schemata_list(void)
>   
>   		s->res = r;
>   		s->num_closid = resctrl_arch_get_num_closid(r);

Above seems to be last user of this helper remaining ... why is helper 
needed instead of something similar to below?

> +		s->conf_type = resctrl_to_arch_res(r)->conf_type;
>   
>   		INIT_LIST_HEAD(&s->list);
>   		list_add(&s->list, &resctrl_all_schema);
> diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
> index b32152968bca..20d8b6dd4af4 100644
> --- a/include/linux/resctrl.h
> +++ b/include/linux/resctrl.h
> @@ -15,6 +15,12 @@ int proc_resctrl_show(struct seq_file *m,
>   
>   #endif
>   
> +enum resctrl_conf_type {
> +	CDP_BOTH,
> +	CDP_CODE,
> +	CDP_DATA,
> +};
> +
>   /**
>    * struct rdt_domain - group of cpus sharing an RDT resource
>    * @list:		all instances of this resource
> @@ -165,11 +171,13 @@ struct rdt_resource {
>   
>   /**
>    * @list:	Member of resctrl's schema list
> + * @cdp_type:	Whether this entry is for code/data/both

Typo? This is fixed in the next patch so that hunk could be merged here.

>    * @res:	The rdt_resource for this entry
>    * @num_closid	Number of CLOSIDs available for this resource
>    */
>   struct resctrl_schema {
>   	struct list_head		list;
> +	enum resctrl_conf_type		conf_type;
>   	struct rdt_resource		*res;
>   	u32				num_closid;
>   };
> 

Reinette