Re: [PATCH 1/9] mm/rmap: make nr_pages signed in try_to_unmap_one

[Matthew Wilcox]

On Tue, Mar 10, 2026 at 01:53:21PM +0530, Dev Jain wrote:
> So when I was playing around with the code, I noticed that passing
> unsigned int nr_pages to add_mm_counter(-nr_pages) messes up things. Then

Using int (whether signed or unsigned) to store nr_pages is a bad idea.
Look how many people are asking about supporting PUD-sized folios.
On an ARM 64k PAGE_SIZE machine, that's 2^26 pages which is uncomfortably
close to 2^32.  It'll only take one more level to exceed that, so, what,
five to ten more years?

Just use unsigned long everywhere now and save ourselves the grief later.