Re: [RFC PATCH] mm/mglru: fix ineffective memory protection for non-kswapd reclaim

["Michal Koutný" <mkoutny@suse.com>]

[-- Attachment #1: Type: text/plain, Size: 1232 bytes --]

Hi Ridong.

On Thu, Aug 27, 2026 at 09:29:13AM +0800, Ridong Chen <ridong.chen@linux.dev> wrote:
> On 8/26/2026 9:47 PM, sashiko-bot@kernel.org wrote:
> > Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> > 
> > Pre-existing issues:
> > - [High] Integer overflow in `effective_protection()` calculations on systems with >= 16TB RAM.
> > --
> > 
> 
> Thanks for the careful analysis. You're right that this is pre-existing in
> effective_protection() and not introduced by this patch.
> 
> I'm not sure it's worth fixing in practice, though — the overflow requires
> systems with >= 16TB of RAM, which I've never encountered
> myself. So I'd rather not fold a fix for it into this patch.
> 
> I'd like to hear the maintainers' thoughts on whether this is worth
> addressing separately.

Machines with >=16 TiB aren't completely out of reach [1]. Then
configuring such protections to attain the overflow is another
condition, so I'd consider this a nice to have but not a
pressing fixup (separately, with thorough review of occurences where
total page counts/bytes might get multiplied).

HTH,
Michal

[1] E.g. https://aws.amazon.com/ec2/instance-types/u7i/

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 265 bytes --]