linux-kernel - Re: [PATCH v7 23/24] x86/resctrl: Introduce interface to list assignment states of all the groups

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Message-ID: <fd370cfa-cee7-4b3a-8a95-b6047794d475@intel.com>
Date: Thu, 19 Sep 2024 10:53:03 -0700
From: Reinette Chatre <reinette.chatre@...el.com>
To: Babu Moger <babu.moger@....com>, <corbet@....net>, <fenghua.yu@...el.com>,
	<tglx@...utronix.de>, <mingo@...hat.com>, <bp@...en8.de>,
	<dave.hansen@...ux.intel.com>
CC: <x86@...nel.org>, <hpa@...or.com>, <paulmck@...nel.org>,
	<rdunlap@...radead.org>, <tj@...nel.org>, <peterz@...radead.org>,
	<yanjiewtw@...il.com>, <kim.phillips@....com>, <lukas.bulwahn@...il.com>,
	<seanjc@...gle.com>, <jmattson@...gle.com>, <leitao@...ian.org>,
	<jpoimboe@...nel.org>, <rick.p.edgecombe@...el.com>,
	<kirill.shutemov@...ux.intel.com>, <jithu.joseph@...el.com>,
	<kai.huang@...el.com>, <kan.liang@...ux.intel.com>,
	<daniel.sneddon@...ux.intel.com>, <pbonzini@...hat.com>,
	<sandipan.das@....com>, <ilpo.jarvinen@...ux.intel.com>,
	<peternewman@...gle.com>, <maciej.wieczor-retman@...el.com>,
	<linux-doc@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<eranian@...gle.com>, <james.morse@....com>
Subject: Re: [PATCH v7 23/24] x86/resctrl: Introduce interface to list
 assignment states of all the groups

Hi Babu,

On 9/4/24 3:21 PM, Babu Moger wrote:
> Provide the interface to list the assignment states of all the resctrl
> groups in mbm_cntr_assign mode.
> 
> Example:
> $cat /sys/fs/resctrl/info/L3_MON/mbm_assign_control

It is not clear what is intended with above example, was it intended to 
have some output?

> 
> List follows the following format:
> 
> "<CTRL_MON group>/<MON group>/<domain_id>=<flags>"
> 
> Format for specific type of groups:
> 
> - Default CTRL_MON group:
>   "//<domain_id>=<flags>"
> 
> - Non-default CTRL_MON group:
>   "<CTRL_MON group>//<domain_id>=<flags>"
> 
> - Child MON group of default CTRL_MON group:
>   "/<MON group>/<domain_id>=<flags>"
> 
> - Child MON group of non-default CTRL_MON group:
>   "<CTRL_MON group>/<MON group>/<domain_id>=<flags>"
> 
> Flags can be one of the following:
> t  MBM total event is enabled
> l  MBM local event is enabled
> tl Both total and local MBM events are enabled
> _  None of the MBM events are enabled
> 
> Signed-off-by: Babu Moger <babu.moger@....com>
> ---

> +"mbm_assign_control":
> +	Reports the resctrl group and monitor status of each group.
> +
> +	List follows the following format:
> +		"<CTRL_MON group>/<MON group>/<domain_id>=<flags>"
> +
> +	Format for specific type of groups:
> +
> +	* Default CTRL_MON group:
> +		"//<domain_id>=<flags>"
> +
> +	* Non-default CTRL_MON group:
> +		"<CTRL_MON group>//<domain_id>=<flags>"
> +
> +	* Child MON group of default CTRL_MON group:
> +		"/<MON group>/<domain_id>=<flags>"
> +
> +	* Child MON group of non-default CTRL_MON group:
> +		"<CTRL_MON group>/<MON group>/<domain_id>=<flags>"
> +
> +	Flags can be one of the following:
> +	::
> +
> +	 t  MBM total event is assigned.
> +	 l  MBM local event is assigned.
> +	 tl Both total and local MBM events are assigned.
> +	 _  None of the MBM events are assigned.
> +
> +	Examples:
> +	::
> +
> +	 # mkdir /sys/fs/resctrl/mon_groups/child_default_mon_grp
> +	 # mkdir /sys/fs/resctrl/non_default_ctrl_mon_grp
> +	 # mkdir /sys/fs/resctrl/non_default_ctrl_mon_grp/mon_groups/child_non_default_mon_grp
> +
> +	 # cat /sys/fs/resctrl/info/L3_MON/mbm_assign_control
> +	 non_default_ctrl_mon_grp//0=tl;1=tl;
> +	 non_default_ctrl_mon_grp/child_non_default_mon_grp/0=tl;1=tl;
> +	 //0=tl;1=tl;
> +	 /child_default_mon_grp/0=tl;1=tl;
> +
> +	 There are four resctrl groups. All the groups have total and local MBM events
> +	 assigned on domain 0 and 1.
> +

Please create the docs in chosen format, like htmldocs, and see how it ends up being formatted.
For example, above seems to be intended to be a code sample but the description ("There are
four resctrl ...") appears as part of the code sample.

>  "max_threshold_occupancy":
>  		Read/write file provides the largest value (in
>  		bytes) at which a previously used LLC_occupancy

...

> +static int rdtgroup_mbm_assign_control_show(struct kernfs_open_file *of,
> +					    struct seq_file *s, void *v)
> +{
> +	struct rdt_resource *r = of->kn->parent->priv;
> +	struct rdt_mon_domain *dom;
> +	struct rdtgroup *rdtg;
> +	char str[10];
> +
> +	mutex_lock(&rdtgroup_mutex);
> +
> +	if (!resctrl_arch_mbm_cntr_assign_enabled(r)) {
> +		rdt_last_cmd_puts("mbm_cntr_assign mode is not enabled\n");
> +		mutex_unlock(&rdtgroup_mutex);
> +		return -EINVAL;
> +	}
> +
> +	rdt_last_cmd_clear();

This should be done before any attempt to write to the buffer.


Reinette