On Thu, Jul 27, 2023 at 09:29:24AM +0800, Huang, Ying wrote: > Matthew Wilcox <willy@xxxxxxxxxxxxx> writes: > > I think that can make sense. Because we limit to a single page table, > > specifying 'nr = 1 << PMD_ORDER' is the same as 'compound = true'. > > Just make it folio, page, nr, vma. I'd actually prefer it as (vma, > > folio, page, nr), but that isn't the convention we've had in rmap up > > until now. > > IIUC, even if 'nr = 1 << PMD_ORDER', we may remove one PMD 'compound' > mapping, or 'nr' PTE mapping. So, we will still need 'compound' (or > some better name) as parameter. Oh, this is removing ... so you're concerned with the case where we've split the PMD into PTEs, but all the PTEs are still present in a single page table? OK, I don't have a good answer to that. Maybe that torpedoes the whole idea; I'll think about it.
