On Fri, Nov 28, 2025 at 03:41:40PM +1100, Jordan Niethe wrote: > A consequence of placing the device private pages outside of the > physical address space is that they no longer have a PFN. However, it is > still necessary to be able to look up a corresponding device private > page from a device private PTE entry, which means that we still require > some way to index into this device private address space. This leads to > the idea of a device private PFN. This is like a PFN but instead of
Don't call it a "device private PFN". That's going to lead to confusion. Device private index? Device memory index? > By removing the device private pages from the physical address space, > this RFC also opens up the possibility to moving away from tracking > device private memory using struct pages in the future. This is > desirable as on systems with large amounts of memory these device > private struct pages use a signifiant amount of memory and take a > significant amount of time to initialize. I did tell Jerome he was making a huge mistake with his design, but he forced it in anyway.
