Re: [PATCH v5 3/4] mm: support large folios swapin as a whole for zRAM-like swapfile

[Chuanhua Han <chuanhuahan@gmail.com>]

Matthew Wilcox <willy@infradead.org> 于2024年7月29日周一 11:51写道：
>
> On Fri, Jul 26, 2024 at 09:46:17PM +1200, Barry Song wrote:
> > -                     folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0,
> > -                                             vma, vmf->address, false);
> > +                     folio = alloc_swap_folio(vmf);
> >                       page = &folio->page;
>
> This is no longer correct.  You need to set 'page' to the precise page
> that is being faulted rather than the first page of the folio.  It was
> fine before because it always allocated a single-page folio, but now it
> must use folio_page() or folio_file_page() (whichever has the correct
> semantics for you).
>
> Also you need to fix your test suite to notice this bug.  I suggest
> doing that first so that you know whether you've got the calculation
> correct.

>
>
This is no problem now, we support large folios swapin as a whole, so
the head page is used here instead of the page that is being faulted.
You can also refer to the current code context, now support large
folios swapin as a whole, and previously only support small page
swapin is not the same.

-- 
Thanks,
Chuanhua