linux-kernel - Re: [PATCH v2] ACPI : Update platform device numa node based on

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Date:   Wed, 12 Apr 2017 16:42:00 +0800
From:   Hanjun Guo <hanjun.guo@...aro.org>
To:     Shanker Donthineni <shankerd@...eaurora.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:     Len Brown <lenb@...nel.org>,
        linux-acpi <linux-acpi@...r.kernel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Viram Sethi <vikrams@...eaurora.org>
Subject: Re: [PATCH v2] ACPI : Update platform device numa node based on _PXM
 method

On 2017/3/29 19:39, Shanker Donthineni wrote:
> The optional _PXM method evaluates to an integer that identifies the
> proximity domain of a device object. On ACPI based kernel boot, the
> field numa_node in 'struct device' is always set to -1 irrespective
> of _PXM value that is specified in the ACPI device object. But in
> case of device-tree based kernel boot the numa_node field is populated
> and reflects to a DT property that is specified in DTS according to
> the below document.
>
> https://www.kernel.org/doc/Documentation/devicetree/bindings/numa.txt
> http://lxr.free-electrons.com/source/drivers/of/device.c#L54
>
> Without this patch dev_to_node() always returns a value of -1 for all
> platform devices. This patch implements support for ACPI _PXM method
> and updates the platform device numa node id using acpi_get_node(),
> which provides the PXM to NUMA mapping information. The individual
> platform device drivers should be able to use the NUMA aware memory
> allocation functions kmalloc_node() and alloc_pages_node() to improve
> the performance.
>
> Signed-off-by: Shanker Donthineni <shankerd@...eaurora.org>
> ---
> Changes since v1: Edited commit text.
>
> Not all the platform devices are attached to NUMA node 0 on Qualcomm
> Datacenter Technologies server chips. Platform device drivers needs
> to be aware of NUMA information to improve performance.
>
>  drivers/acpi/acpi_platform.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/acpi/acpi_platform.c b/drivers/acpi/acpi_platform.c
> index b4c1a6a..83d953e 100644
> --- a/drivers/acpi/acpi_platform.c
> +++ b/drivers/acpi/acpi_platform.c
> @@ -119,11 +119,14 @@ struct platform_device *acpi_create_platform_device(struct acpi_device *adev,
>  	if (IS_ERR(pdev))
>  		dev_err(&adev->dev, "platform device creation failed: %ld\n",
>  			PTR_ERR(pdev));
> -	else
> +	else {
> +		set_dev_node(&pdev->dev, acpi_get_node(adev->handle));
>  		dev_dbg(&adev->dev, "created platform device %s\n",
>  			dev_name(&pdev->dev));
> +	}
>
>  	kfree(resources);
> +
>  	return pdev;
>  }
>  EXPORT_SYMBOL_GPL(acpi_create_platform_device);

Reviewed-by: Hanjun Guo <hanjun.guo@...aro.org>

Thanks
Hanjun