linux-kernel - Re: [RFC 06/12] fs/resctrl: Extend schemata read for priority partition control

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Message-ID: <c9466b46-6a03-e57b-4b8c-edeae8081951@intel.com>
Date:   Thu, 17 Aug 2023 10:42:58 -0700
From:   Fenghua Yu <fenghua.yu@...el.com>
To:     Amit Singh Tomar <amitsinght@...vell.com>,
        <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>
CC:     <reinette.chatre@...el.com>, <james.morse@....com>,
        <gcherian@...vell.com>, <robh@...nel.org>, <peternewman@...gle.com>
Subject: Re: [RFC 06/12] fs/resctrl: Extend schemata read for priority
 partition control

Hi, Amit,

On 8/15/23 08:27, Amit Singh Tomar wrote:
> At present, "schemata" file under resource control group reveals
> information about Cache portion bitmap and Memory Bandwidth allocation.
> With the introduction of priority partition control "schemata" is updated
> to adopt priority value.
> 
> Let's enable support for reading the priority values for "schemata" file.
> 
> Signed-off-by: Amit Singh Tomar <amitsinght@...vell.com>
> ---
>   drivers/platform/mpam/mpam_resctrl.c |  4 ++++
>   fs/resctrl/ctrlmondata.c             | 15 ++++++++++++---
>   include/linux/resctrl.h              |  4 ++++
>   3 files changed, 20 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/platform/mpam/mpam_resctrl.c b/drivers/platform/mpam/mpam_resctrl.c
> index cc843f1b0fb7..b491a0f897fd 100644
> --- a/drivers/platform/mpam/mpam_resctrl.c
> +++ b/drivers/platform/mpam/mpam_resctrl.c
> @@ -735,7 +735,11 @@ static int mpam_resctrl_resource_init(struct mpam_resctrl_res *res)
>   
>   		if (has_ppart) {
>   			r->priority_cap = true;
> +			if (class->props.dspri_wd > 0x10)
> +				class->props.dspri_wd = 0x10;
> +
>   			r->dspri_default_ctrl = BIT_MASK(class->props.dspri_wd) - 1;
> +			r->dspri_data_width = (class->props.dspri_wd + 3) / 4;
>   		}
>   
>   		/*
> diff --git a/fs/resctrl/ctrlmondata.c b/fs/resctrl/ctrlmondata.c
> index b19ac2509e38..8c8a4d09d22c 100644
> --- a/fs/resctrl/ctrlmondata.c
> +++ b/fs/resctrl/ctrlmondata.c
> @@ -379,7 +379,7 @@ static void show_doms(struct seq_file *s, struct resctrl_schema *schema, int clo
>   	struct rdt_resource *r = schema->res;
>   	struct rdt_domain *dom;
>   	bool sep = false;
> -	u32 ctrl_val;
> +	u32 ctrl_val, dspri_ctrl_val;
>   
>   	/* Walking r->domains, ensure it can't race with cpuhp */
>   	lockdep_assert_cpus_held();
> @@ -395,9 +395,18 @@ static void show_doms(struct seq_file *s, struct resctrl_schema *schema, int clo
>   			ctrl_val = resctrl_arch_get_config(r, dom, closid,
>   							   schema->conf_type);
>   
> -		seq_printf(s, r->format_str, dom->id, max_data_width,
> -			   ctrl_val);
> +		if (r->priority_cap) {
> +			r->dspri_show = true;
> +			dspri_ctrl_val = resctrl_arch_get_config(r, dom, closid,
> +								 CDP_NONE);
> +			seq_printf(s, r->format_str, dom->id, max_data_width, ctrl_val,
> +					r->dspri_data_width, dspri_ctrl_val);

Move r->dspri_show = false to here.

> +		} else
> +			seq_printf(s, r->format_str, dom->id, max_data_width,
> +				   ctrl_val);
> +
>   		sep = true;
> +		r->dspri_show = false;

dspri_show is irrelevant without priority_cap.

>   	}
>   	seq_puts(s, "\n");
>   }
> diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
> index d5b0661c0f70..d7100c330945 100644
> --- a/include/linux/resctrl.h
> +++ b/include/linux/resctrl.h
> @@ -199,12 +199,14 @@ struct resctrl_membw {
>    * @mon_capable:	Is monitor feature available on this machine
>    * @priority_capable:   Is priority partitioning feature available on this machine
>    * @dspri_store:
> + * @dspri_show:		flag to indicate downstream priority read
>    * @num_rmid:		Number of RMIDs available
>    * @cache_level:	Which cache level defines scope of this resource
>    * @cache:		Cache allocation related data
>    * @membw:		If the component has bandwidth controls, their properties.
>    * @domains:		RCU list of all domains for this resource
>    * @name:		Name to use in "schemata" file.
> + * @dspri_data_width    Character width of dspri value when displaying
>    * @data_width:		Character width of data when displaying
>    * @default_ctrl:	Specifies default cache cbm or memory B/W percent.
>    * @dspri_default_ctrl: Specifies default downstream priority value.
> @@ -219,6 +221,7 @@ struct rdt_resource {
>   	bool			mon_capable;
>   	bool                    priority_cap;
>   	bool			dspri_store;
> +	bool                    dspri_show;
>   	int			num_rmid;
>   	int			cache_level;
>   	struct resctrl_cache	cache;
> @@ -226,6 +229,7 @@ struct rdt_resource {
>   	struct list_head	domains;
>   	char			*name;
>   	int			data_width;
> +	int			dspri_data_width;
>   	u32			default_ctrl;
>   	u32			dspri_default_ctrl;
>   	const char		*format_str;

Thanks.

-Fenghua