Re: [PATCH 1/1] mm: prevent poison consumption when splitting THP

[David Hildenbrand]

On 29.09.25 18:30, Zhuo, Qiuxu wrote:
> Hi Tony,
>
> > From: Luck, Tony <tony.luck@xxxxxxxxx>
> > [...]
> > Subject: RE: [PATCH 1/1] mm: prevent poison consumption when splitting THP
> >
> > > Miaohe mentioned in another e-mail that there was an HWPoisoned flag
> > for the raw error 4K page.
> > > We could use that flag just to skip that raw error page and still use
> > > the zeropage for other healthy sub-pages. I'll try that.
> >
> > That HWPoisoned flag is only set for raw pages where an error has been
> > detected. Maybe Linux could implement an
> > "is_this_page_all_zero_mc_safe()"[1] that would catch undetected poison
>
> This sounds like a great suggestion to me.
> Let's see what others think about this and the name (though the name already LGTM 😊).

The function name is just ... special. Not the good type of special IMHO. :)

Note that we'll be moving to pages_identical() in [1]. Maybe we would 
want a pages_identical_mc() or sth. like that as a follow up later.


So in any case, make that a follow-up work on top of a simple fix.

[1] https://lore.kernel.org/all/20250922021458.68123-1-lance.yang@xxxxxxxxx/

--
Cheers

David / dhildenb