linux-kernel - Re: [PATCH v6 04/42] x86/resctrl: Use schema type to determine how to parse schema values

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Message-ID: <e47db1dc-72cc-434f-bd07-4f0a1ffc6d36@intel.com>
Date: Wed, 19 Feb 2025 13:52:07 -0800
From: Reinette Chatre <reinette.chatre@...el.com>
To: James Morse <james.morse@....com>, <x86@...nel.org>,
	<linux-kernel@...r.kernel.org>
CC: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>, H Peter Anvin <hpa@...or.com>, Babu Moger
	<Babu.Moger@....com>, <shameerali.kolothum.thodi@...wei.com>, "D Scott
 Phillips OS" <scott@...amperecomputing.com>, <carl@...amperecomputing.com>,
	<lcherian@...vell.com>, <bobo.shaobowang@...wei.com>,
	<tan.shaopeng@...itsu.com>, <baolin.wang@...ux.alibaba.com>, Jamie Iles
	<quic_jiles@...cinc.com>, Xin Hao <xhao@...ux.alibaba.com>,
	<peternewman@...gle.com>, <dfustini@...libre.com>, <amitsinght@...vell.com>,
	David Hildenbrand <david@...hat.com>, Rex Nie <rex.nie@...uarmicro.com>,
	"Dave Martin" <dave.martin@....com>, Koba Ko <kobak@...dia.com>, Shanker
 Donthineni <sdonthineni@...dia.com>, Shaopeng Tan
	<tan.shaopeng@...fujitsu.com>, "Tony Luck" <tony.luck@...el.com>
Subject: Re: [PATCH v6 04/42] x86/resctrl: Use schema type to determine how to
 parse schema values

Hi James,

On 2/7/25 10:17 AM, James Morse wrote:
> Resctrl's architecture code gets to specify a function pointer that is
> used when parsing schema entries. This is expected to be one of two
> helpers from the filesystem code.
> 
> Setting this function pointer allows the architecture code to change
> the ABI resctrl presents to user-space, and forces resctrl to expose
> these helpers.
> 
> Instead, add a schema format enum to choose which schema parser to
> use. This allows the helpers to be made static and the structs used
> for passing arguments moved out of shared headers.
> 
> Signed-off-by: James Morse <james.morse@....com>
> Tested-by: Carl Worth <carl@...amperecomputing.com> # arm64
> Tested-by: Shaopeng Tan <tan.shaopeng@...fujitsu.com>
> Reviewed-by: Shaopeng Tan <tan.shaopeng@...fujitsu.com>
> Reviewed-by: Tony Luck <tony.luck@...el.com>
> ---

...

> diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
> index 496ddcaa4ecf..aed231a6d30c 100644
> --- a/include/linux/resctrl.h
> +++ b/include/linux/resctrl.h
> @@ -183,7 +183,6 @@ struct resctrl_membw {
>  	u32				*mb_map;
>  };
>  
> -struct rdt_parse_data;
>  struct resctrl_schema;
>  
>  enum resctrl_scope {
> @@ -192,6 +191,16 @@ enum resctrl_scope {
>  	RESCTRL_L3_NODE,
>  };
>  
> +/**
> + * enum resctrl_schema_fmt - The format user-space provides for a schema.
> + * @RESCTRL_SCHEMA_BITMAP:	The schema is a bitmap in hex.
> + * @RESCTRL_SCHEMA_RANGE:	The schema is a decimal number,

Nit: Please let sentence end with a period.

> + */
> +enum resctrl_schema_fmt {
> +	RESCTRL_SCHEMA_BITMAP,
> +	RESCTRL_SCHEMA_RANGE,
> +};
> +
>  /**
>   * struct rdt_resource - attributes of a resctrl resource
>   * @rid:		The index of the resource
> @@ -208,7 +217,7 @@ enum resctrl_scope {
>   * @data_width:		Character width of data when displaying
>   * @default_ctrl:	Specifies default cache cbm or memory B/W percent.
>   * @format_str:		Per resource format string to show domain value
> - * @parse_ctrlval:	Per resource function pointer to parse control values
> + * @schema_fmt:		Which format string and parser is used for this schema.
>   * @evt_list:		List of monitoring events
>   * @cdp_capable:	Is the CDP feature available on this resource
>   */
> @@ -227,9 +236,7 @@ struct rdt_resource {
>  	int			data_width;
>  	u32			default_ctrl;
>  	const char		*format_str;
> -	int			(*parse_ctrlval)(struct rdt_parse_data *data,
> -						 struct resctrl_schema *s,
> -						 struct rdt_ctrl_domain *d);
> +	enum resctrl_schema_fmt	schema_fmt;
>  	struct list_head	evt_list;
>  	bool			cdp_capable;
>  };

| Reviewed-by: Reinette Chatre <reinette.chatre@...el.com>

Reinette