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

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Message-ID: <18560c7a-c9c5-1cf1-2e74-cf28c3a16b97@codeaurora.org>
Date:   Tue, 28 Mar 2017 17:51:20 -0500
From:   Shanker Donthineni <shankerd@...eaurora.org>
To:     "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>,
        Vikram Sethi <vikrams@...eaurora.org>
Subject: Re: [PATCH] ACPI : Update platform device numa node based on _PXM
 method

Hi Rafael,


On 03/28/2017 05:15 PM, Rafael J. Wysocki wrote:
> On Tuesday, March 28, 2017 05:14:13 PM Shanker Donthineni wrote:
>> Hi Rafael,
>>
>>
>> On 03/28/2017 04:43 PM, Rafael J. Wysocki wrote:
>>> On Tuesday, March 21, 2017 09:54:30 AM Shanker Donthineni wrote:
>>>> The optional _PXM method evaluates to an integer that identifies the
>>>> proximity domain of a device object. 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.
>>>>
>>>> Signed-off-by: Shanker Donthineni <shankerd@...eaurora.org>
>>> What exactly is the motivation here?
>> We have a couple of platform devices some of them are attached
>> to socket0 and others to a different socket. We would like to covert
>> memory allocations in Qualcomm platform device drivers to a NUMA
>> aware allocation to improve performance.
> All of the above information should be there in the patch changelog and
> presumably the patch should be a part of a larger series so the way this
> feature is going to be used is more clear.

Sorry, I didn't quite get what's larger series? I'm happy to include above information in commit/changelog text. We are trying to allocate memory using standard  function devm_kmalloc() but the function is always allocating memory from NUMA node 0. The inline function dev_to_node(dev) always returns -1 on our system even though we are setting PXM method in ACPI DSDT to non-zero value.

For device tree based kernel, the field 'dev->numa_node' is populated based on the DT property which is specified according to the below document. But in case of ACPI based kernel this NUMA field is always initialized to -1 for platform devices.

https://www.kernel.org/doc/Documentation/devicetree/bindings/numa.txt

Please guide me, should I send v2 patch with the suggested changelog text? otherwise I don't have any other patches to show our use case.

>
> Thanks,
> Rafael
>

-- 
Shanker Donthineni
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.