linux-kernel - Re: [PATCH v4 18/20] arch_topology: Set cluster identifier in each core/thread from /cpu-map

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Message-ID: <Yrm05bAzu6c29XXB@arm.com>
Date:   Mon, 27 Jun 2022 14:47:17 +0100
From:   Ionela Voinescu <ionela.voinescu@....com>
To:     Sudeep Holla <sudeep.holla@....com>
Cc:     linux-kernel@...r.kernel.org, Greg KH <gregkh@...uxfoundation.org>,
        Atish Patra <atishp@...shpatra.org>,
        Atish Patra <atishp@...osinc.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Qing Wang <wangqing@...o.com>,
        Rob Herring <robh+dt@...nel.org>,
        "Rafael J . Wysocki" <rafael@...nel.org>,
        Pierre Gondois <pierre.gondois@....com>,
        linux-arm-kernel@...ts.infradead.org,
        linux-riscv@...ts.infradead.org
Subject: Re: [PATCH v4 18/20] arch_topology: Set cluster identifier in each
 core/thread from /cpu-map

On Tuesday 21 Jun 2022 at 20:20:32 (+0100), Sudeep Holla wrote:
> Let us set the cluster identifier as parsed from the device tree
> cluster nodes within /cpu-map.
> 
> We don't support nesting of clusters yet as there are no real hardware
> to support clusters of clusters.
> 
> Signed-off-by: Sudeep Holla <sudeep.holla@....com>
> ---
>  drivers/base/arch_topology.c | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
> index 39be5dbaf4da..75604f783bfc 100644
> --- a/drivers/base/arch_topology.c
> +++ b/drivers/base/arch_topology.c
> @@ -497,7 +497,7 @@ static int __init get_cpu_for_node(struct device_node *node)
>  }
>  
>  static int __init parse_core(struct device_node *core, int package_id,
> -			     int core_id)
> +			     int cluster_id, int core_id)
>  {
>  	char name[20];
>  	bool leaf = true;
> @@ -513,6 +513,7 @@ static int __init parse_core(struct device_node *core, int package_id,
>  			cpu = get_cpu_for_node(t);
>  			if (cpu >= 0) {
>  				cpu_topology[cpu].package_id = package_id;
> +				cpu_topology[cpu].cluster_id = cluster_id;
>  				cpu_topology[cpu].core_id = core_id;
>  				cpu_topology[cpu].thread_id = i;
>  			} else if (cpu != -ENODEV) {
> @@ -534,6 +535,7 @@ static int __init parse_core(struct device_node *core, int package_id,
>  		}
>  
>  		cpu_topology[cpu].package_id = package_id;
> +		cpu_topology[cpu].cluster_id = cluster_id;
>  		cpu_topology[cpu].core_id = core_id;
>  	} else if (leaf && cpu != -ENODEV) {
>  		pr_err("%pOF: Can't get CPU for leaf core\n", core);
> @@ -543,7 +545,8 @@ static int __init parse_core(struct device_node *core, int package_id,
>  	return 0;
>  }
>  
> -static int __init parse_cluster(struct device_node *cluster, int depth)
> +static int __init
> +parse_cluster(struct device_node *cluster, int cluster_id, int depth)
>  {
>  	char name[20];
>  	bool leaf = true;
> @@ -563,7 +566,7 @@ static int __init parse_cluster(struct device_node *cluster, int depth)
>  		c = of_get_child_by_name(cluster, name);
>  		if (c) {
>  			leaf = false;
> -			ret = parse_cluster(c, depth + 1);
> +			ret = parse_cluster(c, i, depth + 1);
>  			of_node_put(c);
>  			if (ret != 0)
>  				return ret;
> @@ -587,7 +590,7 @@ static int __init parse_cluster(struct device_node *cluster, int depth)
>  			}
>  
>  			if (leaf) {
> -				ret = parse_core(c, 0, core_id++);
> +				ret = parse_core(c, 0, cluster_id, core_id++);
>  			} else {
>  				pr_err("%pOF: Non-leaf cluster with core %s\n",
>  				       cluster, name);
> @@ -626,7 +629,7 @@ static int __init parse_dt_topology(void)
>  	if (!map)
>  		goto out;
>  
> -	ret = parse_cluster(map, 0);
> +	ret = parse_cluster(map, -1, 0);
>  	if (ret != 0)
>  		goto out_map;
>  
> -- 
> 2.36.1
> 

Reviewed-by: Ionela Voinescu <ionela.voinescu@....com>

Thanks,
Ionela.