On Wed, Nov 08, 2023 at 09:40:09AM +0800, Kefeng Wang wrote:
>
>
> On 2023/11/7 22:24, Matthew Wilcox wrote:
> > On Tue, Nov 07, 2023 at 09:52:11PM +0800, Kefeng Wang wrote:
> > > struct page *ksm_might_need_to_copy(struct page *page,
> > > - struct vm_area_struct *vma, unsigned long address)
> > > + struct vm_area_struct *vma, unsigned long addr)
> > > {
> > > struct folio *folio = page_folio(page);
> > > struct anon_vma *anon_vma = folio_anon_vma(folio);
> > > - struct page *new_page;
> > > + struct folio *new_folio;
> > > - if (PageKsm(page)) {
> > > - if (page_stable_node(page) &&
> > > + if (folio_test_ksm(folio)) {
> > > + if (folio_stable_node(folio) &&
> > > !(ksm_run & KSM_RUN_UNMERGE))
> > > return page; /* no need to copy it */
> > > } else if (!anon_vma) {
> > > return page; /* no need to copy it */
> > > - } else if (page->index == linear_page_index(vma, address) &&
> > > + } else if (page->index == linear_page_index(vma, addr) &&
> >
> > Hmm. page->index is going away. What should we do here instead?
>
> Do you mean to replace page->index to folio->index, or kill index from
> struct page?
I'm asking you what we should do.
Tail pages already don't have a valid ->index (or ->mapping).
So presumably we can't see a tail page here today. But will we in future?
Just to remind you, the goal here is:
struct page {
unsigned long memdesc;
};
so folios will be the only thing that have a ->index. I haven't looked
at this code; I know nothing about it. But you're changing it, so you
must have some understanding of it.
