linux-kernel - Re: [PATCH 3/7] x86/resctrl: Add a new node-scoped resource to rdt_resources

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Date:   Tue, 28 Feb 2023 08:27:26 -0600
From:   "Moger, Babu" <bmoger@....com>
To:     Tony Luck <tony.luck@...el.com>, Fenghua Yu <fenghua.yu@...el.com>,
        Reinette Chatre <reinette.chatre@...el.com>,
        Peter Newman <peternewman@...gle.com>,
        Jonathan Corbet <corbet@....net>,
        "x86@...nel.org" <x86@...nel.org>
Cc:     Shaopeng Tan <tan.shaopeng@...itsu.com>,
        James Morse <james.morse@....com>,
        Jamie Iles <quic_jiles@...cinc.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>,
        "patches@...ts.linux.dev" <patches@...ts.linux.dev>
Subject: Re: [PATCH 3/7] x86/resctrl: Add a new node-scoped resource to
 rdt_resources_all[]

Hi Tony,
Sorry for the late response. I was looking at your patches.

Do you really need a new resource [RDT_RESOURCE_NODE] to handle this 
feature?

As far as I can see, all that matters is writing/reading the MSRs 
IA32_PQR_ASSOC and IA32_QM_EVTSEL based on cpu index. I think that can 
be done without having the new resource. Let me know if I have 
misunderstood something.

Thanks
Babu


> -----Original Message-----
> From: Tony Luck <tony.luck@...el.com>
> Sent: Thursday, January 26, 2023 12:42 PM
> To: Fenghua Yu <fenghua.yu@...el.com>; Reinette Chatre
> <reinette.chatre@...el.com>; Peter Newman <peternewman@...gle.com>;
> Jonathan Corbet <corbet@....net>; x86@...nel.org
> Cc: Shaopeng Tan <tan.shaopeng@...itsu.com>; James Morse
> <james.morse@....com>; Jamie Iles <quic_jiles@...cinc.com>; Moger, Babu
> <Babu.Moger@....com>; linux-kernel@...r.kernel.org; linux-
> doc@...r.kernel.org; patches@...ts.linux.dev; Tony Luck
> <tony.luck@...el.com>
> Subject: [PATCH 3/7] x86/resctrl: Add a new node-scoped resource to
> rdt_resources_all[]
> 
> Add a placeholder in the array of struct rdt_hw_resource to be used for event
> monitoring of systems with Sub-NUMA Cluster enabled.
> 
> Update get_domain_id() to handle SCOPE_NODE.
> 
> Signed-off-by: Tony Luck <tony.luck@...el.com>
> ---
>  arch/x86/kernel/cpu/resctrl/internal.h |  2 ++
>  arch/x86/kernel/cpu/resctrl/core.c     | 12 ++++++++++++
>  2 files changed, 14 insertions(+)
> 
> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h
> b/arch/x86/kernel/cpu/resctrl/internal.h
> index 15cea517efaa..39a62babd60b 100644
> --- a/arch/x86/kernel/cpu/resctrl/internal.h
> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
> @@ -409,12 +409,14 @@ enum resctrl_res_level {
>  	RDT_RESOURCE_L3,
>  	RDT_RESOURCE_L2,
>  	RDT_RESOURCE_MBA,
> +	RDT_RESOURCE_NODE,
> 
>  	/* Must be the last */
>  	RDT_NUM_RESOURCES,
>  };
> 
>  enum resctrl_scope {
> +	SCOPE_NODE,
>  	SCOPE_L2_CACHE = 2,
>  	SCOPE_L3_CACHE = 3
>  };
> diff --git a/arch/x86/kernel/cpu/resctrl/core.c
> b/arch/x86/kernel/cpu/resctrl/core.c
> index 6914232acf84..19be6fe42ef3 100644
> --- a/arch/x86/kernel/cpu/resctrl/core.c
> +++ b/arch/x86/kernel/cpu/resctrl/core.c
> @@ -100,6 +100,16 @@ struct rdt_hw_resource rdt_resources_all[] = {
>  			.fflags			= RFTYPE_RES_MB,
>  		},
>  	},
> +	[RDT_RESOURCE_NODE] =
> +	{
> +		.r_resctrl = {
> +			.rid			= RDT_RESOURCE_NODE,
> +			.name			= "L3",
> +			.scope			= SCOPE_NODE,
> +			.domains		=
> domain_init(RDT_RESOURCE_NODE),
> +			.fflags			= RFTYPE_RES_MB,
> +		},
> +	},
>  };
> 
>  /*
> @@ -464,6 +474,8 @@ static int arch_domain_mbm_alloc(u32 num_rmid,
> struct rdt_hw_domain *hw_dom)
> 
>  static int get_domain_id(int cpu, enum resctrl_scope scope)  {
> +	if (scope == SCOPE_NODE)
> +		return cpu_to_node(cpu);
>  	return get_cpu_cacheinfo_id(cpu, scope);  }
> 
> --
> 2.39.1