Re: [PATCH] mm: page_alloc: simpify page del and expand

[Andrew Morton]

On Mon, 26 Aug 2024 14:40:48 +0800 Huan Yang <link@xxxxxxxx> wrote:

> When page del from buddy and need expand, it will account free_pages
> in zone's migratetype.
> 
> The current way is to subtract the page number of the current order
> when deleting, and then add it back when expanding.
> 
> This is unnecessary, as when migrating the same type, we can directly
> record the difference between the high-order pages and the expand
> added, and then subtract it directly.
> 
> This patch merge that, only when del and expand done, then account
> free_pages.

It isn't obvious to me that this is a significant improvement.  Am I
missing something?