linux-kernel - Re: [PATCH 2/2] mm: keep nid around during hot-remove

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Message-ID: <345ba221-e094-47e8-9481-562faf4acd85@redhat.com>
Date: Wed, 7 Aug 2024 13:32:12 +0200
From: David Hildenbrand <david@...hat.com>
To: Pasha Tatashin <pasha.tatashin@...een.com>, agordeev@...ux.ibm.com,
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Subject: Re: [PATCH 2/2] mm: keep nid around during hot-remove

On 07.08.24 00:14, Pasha Tatashin wrote:
> nid is needed during memory hot-remove in order to account the
> information about the memmap overhead that is being removed.
> 
> In addition, we cannot use page_pgdat(pfn_to_page(pfn)) during
> hotremove after remove_pfn_range_from_zone().
> 
> We also cannot determine nid from walking through memblocks after
> remove_memory_block_devices() is called.
> 
> Therefore, pass nid down from the beginning of hotremove to where
> it is used for the accounting purposes.

I was happy to finally remove that nid parameter for good in:

commit 65a2aa5f482ed0c1b5afb9e6b0b9e0b16bb8b616
Author: David Hildenbrand <david@...hat.com>
Date:   Tue Sep 7 19:55:04 2021 -0700

     mm/memory_hotplug: remove nid parameter from arch_remove_memory()

To ask the real question: Do we really need this counter per-nid at all?

Seems to over-complicate things.

-- 
Cheers,

David / dhildenb