Re: [Patch v2 2/2] mm/huge_memory: Optimize and simplify __split_unmapped_folio() logic

[wang lian <lianux.mm@gmail.com>]

> Existing __split_unmapped_folio() code splits the given folio and update
> stats, but it is complicated to understand.

> After simplification, __split_unmapped_folio() directly calculate and
> update the folio statistics upon a successful split:

> * All resulting folios are @split_order.

> * The number of new folios are calculated directly from @old_order
  and @split_order.

> * The folio for the next split is identified as the one containing
  @split_at.

> * An xas_try_split() error is returned directly without worrying
  about stats updates.

> Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
> Cc: Zi Yan <ziy@nvidia.com>
> Reviewed-by: Zi Yan <ziy@nvidia.com>

The simplification looks great and makes the logic much easier to follow.
The new comment you added is also very helpful for understanding the
difference between the two split modes.

LGTM.

Reviewed-by: wang lian <lianux.mm@gmail.com>

> +		 * For uniform split, we have finished the job.
> +		 * For non-uniform split, we assign folio to the one the one
> +		 * containing @split_at and assign @old_order to @split_order.

--
Best Regards,
wang lian