On Tue, Sep 9, 2025 at 8:24 AM Dave Hansen <dave.hansen@xxxxxxxxx> wrote: > > On 9/9/25 04:16, Kiryl Shutsemau wrote: > > > And it is going to be very wasteful. With huge pages, in most cases, you > > only need dynamic PAMT for control pages. You will have a lot of memory > > sitting in stash with zero use. > > I think it's going to be hard to convince me without actual data on this > one. > * With 1G page backing and with DPAMT entries created only for 4K EPT mappings - ~5MB of DPAMT memory usage for 704G guest memory size. We expect the DPAMT memory usage to be in MBs even with 4096G guest memory size. * With DPAMT entries created for all private memory irrespective of mapping granularity - DPAMT memory usage is around ~3GB for 704G guest memory size and around ~16G for 4096G guest memory size. For a 4TB guest memory size with 1G page backing, the DPAMT memory usage > Even then, we're talking about 0.4% of system memory. So how much code > and complexity are we talking about in order to save a *maximum* of 0.4% > of system memory? >
