Re: [PATCH v5 01/17] mm/zsmalloc: replace PG_private with pointer comparison

[Lance Yang]

On 2026/9/21 10:27, Zi Yan wrote:
> zsmalloc uses PG_private to indicate first zpdesc in a zspage chain. It is
> equivalent to check zpdesc == zspage->first_zpdesc. Replace
> is_first_zpdesc() with zpdesc == zspage->first_zpdesc in obj_allocated().
>
> For get_first_zpdesc(), first_zpdesc is from zspage->first_zpdesc, so
> replace is_first_zpdesc() with first_zpdesc->zspage == zspage, the second
> requirement of a zspage chain, where all zpdescs point to the same zspage.
>
> is_first_zpdesc(), is only used in VM_BUG_ON_PAGE(), so performance impact
> should be negligible. While at it, change VM_BUG_ON() to
> VM_WARN_ON_ONCE_PAGE().
>
> It prepares for a future commit that remove PG_private.
>
> No functional change intended.
>
> Assisted-by: LLM
> To: Minchan Kim <minchan@xxxxxxxxxx>
> To: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
> To: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: linux-mm@xxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
> Reviewed-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
> Acked-by: David Hildenbrand (Arm) <david@xxxxxxxxxx>
> Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
> ---

Nice work! Feel free to add:

Reviewed-by: Lance Yang <lance.yang@xxxxxxxxx>