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Message-ID: <50032a84-9453-8ab3-8d42-5bd8c1504640@os.amperecomputing.com>
Date: Wed, 10 Jul 2019 06:14:23 +0000
From: Hoan Tran OS <hoan@...amperecomputing.com>
To: Thomas Gleixner <tglx@...utronix.de>
CC: Catalin Marinas <catalin.marinas@....com>,
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Open Source Submission <patches@...erecomputing.com>
Subject: Re: [PATCH 3/5] x86: Kconfig: Remove CONFIG_NODES_SPAN_OTHER_NODES
Hi Thomas,
On 7/10/19 12:58 PM, Thomas Gleixner wrote:
> Hoan,
>
> On Wed, 10 Jul 2019, Hoan Tran OS wrote:
>> On 6/25/19 3:45 PM, Thomas Gleixner wrote:
>>> On Tue, 25 Jun 2019, Hoan Tran OS wrote:
>>>> @@ -1567,15 +1567,6 @@ config X86_64_ACPI_NUMA
>>>> ---help---
>>>> Enable ACPI SRAT based node topology detection.
>>>>
>>>> -# Some NUMA nodes have memory ranges that span
>>>> -# other nodes. Even though a pfn is valid and
>>>> -# between a node's start and end pfns, it may not
>>>> -# reside on that node. See memmap_init_zone()
>>>> -# for details.
>>>> -config NODES_SPAN_OTHER_NODES
>>>> - def_bool y
>>>> - depends on X86_64_ACPI_NUMA
>>>
>>> the changelog does not mention that this lifts the dependency on
>>> X86_64_ACPI_NUMA and therefore enables that functionality for anything
>>> which has NUMA enabled including 32bit.
>>>
>>
>> I think this config is used for a NUMA layout which NUMA nodes addresses
>> are spanned to other nodes. I think 32bit NUMA also have the same issue
>> with that layout. Please correct me if I'm wrong.
>
> I'm not saying you're wrong, but it's your duty to provide the analysis why
> this is correct for everything which has NUMA enabled.
>
>>> The core mm change gives no helpful information either. You just copied the
>>> above comment text from some random Kconfig.
>>
>> Yes, as it's a correct comment and is used at multiple places.
>
> Well it maybe correct in terms of explaining what this is about, it still
> does not explain why this is needed by default on everything which has NUMA
> enabled.
Let me send another patch with the detail explanation.
Thanks
Hoan
>
> Thanks,
>
> tglx
>
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