Re: [PATCH 4/9] mm/page_alloc: optimize code layout for __alloc_pages_bulk

[Matthew Wilcox]

On Thu, Mar 25, 2021 at 11:42:23AM +0000, Mel Gorman wrote:
>  
> -	if (WARN_ON_ONCE(nr_pages <= 0))
> +	if (unlikely(nr_pages <= 0))
>  		return 0;

If we made nr_pages unsigned, we wouldn't need this check at all (ok,
we'd still need to figure out what to do with 0).  But then, if a user
inadvertently passes in -ENOMEM, we'll try to allocate 4 billion pages.
So maybe we should check it.  Gah, API design is hard.