On Thu, Dec 19, 2024 at 05:33:32PM +0100, David Hildenbrand wrote: > On 19.12.24 17:22, Matthew Wilcox (Oracle) wrote: > > These two patches compile ... I can promise nothing more than that. > > > > David suggested to me that the gmap code really should be using ptdesc, > > and I think I agree with him. The vsie code looks quite different > > and probably shouldn't be using a ptdesc, but we can use page->private > > instead of page->index. It's not yet clear to me if we'll ever manage > > to get rid of page->private. > > Just curious, does that mean that memdesc would always contain these > additional 8 bytes? Eventually we'll have a choice to make. 1. Shrink struct page to 8 bytes, but we'll need to allocate a 32 byte memdesc for all the current users of page->private 2. Shrink struct page to 16 bytes I genuinely don't know which will be better for the whole system. If you're asking because we can defer some of the mapcount work by using the 8 bytes of page->private to store mapcount, then yes, let's do that.
