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Date: Mon, 8 Apr 2024 10:06:14 -0700 (PDT)
From: "Lameter, Christopher" <cl@os.amperecomputing.com>
To: Andrew Morton <akpm@linux-foundation.org>
cc: Huang Shijie <shijie@os.amperecomputing.com>, gregkh@linuxfoundation.org, 
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Subject: Re: [PATCH v3] NUMA: Early use of cpu_to_node() returns 0 instead
 of the correct node id
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On Wed, 27 Mar 2024, Andrew Morton wrote:

>> In order to fix the bug, the patch introduces early_numa_node_init()
>> which is called after smp_prepare_boot_cpu() in start_kernel.
>> early_numa_node_init will initialize the "numa_node" as soon as
>> the early_cpu_to_node() is ready, before the cpu_to_node() is called
>> at the first time.
>
> What are the userspace-visible runtime effects of this bug?

Performance is reduced since there is increase in off node accesses.