Re: [PATCH v4] mm: fix accounting of memmap pages

[Wei Yang <richard.weiyang@gmail.com>]

On Thu, Aug 07, 2025 at 08:35:45PM +0200, Sumanth Korikkar wrote:
>For !CONFIG_SPARSEMEM_VMEMMAP, memmap page accounting is currently done
>upfront in sparse_buffer_init(). However, sparse_buffer_alloc() may
>return NULL in failure scenario.
>
>Also, memmap pages may be allocated either from the memblock allocator
>during early boot or from the buddy allocator. When removed via
>arch_remove_memory(), accounting of memmap pages must reflect the
>original allocation source.
>
>To ensure correctness:
>* Account memmap pages after successful allocation in sparse_init_nid()
>  and section_activate().
>* Account memmap pages in section_deactivate() based on allocation
>  source.
>
>Cc: stable@vger.kernel.org
>Fixes: 15995a352474 ("mm: report per-page metadata information")
>Suggested-by: David Hildenbrand <david@redhat.com>
>Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>

LGTM

Reviewed-by: Wei Yang <richard.weiyang@gmail.com>

-- 
Wei Yang
Help you, Help me