On October 24, 2023 11:49:07 AM PDT, "Luck, Tony" <tony.luck@xxxxxxxxx> wrote: >> the only overhead to modules other than load time (including the runtime linking) is that modules can't realistically be mapped using large page entries. > >If there were some significant win for using large pages, couldn't the >kernel pre-allocate some 2MB pages in the [-2GiB,0) range? Boot parameter >for how many (perhaps two for separate code/data pages). First few loaded >modules get to use that space until it is all gone. > >It would all be quite messy if those modules were later unloaded/reloaded >... so there would have to be some compelling benchmarks to justify >the complexity. > >That's probably why Peter said "can't realistically". > >-Tony > Sure it could, but it would mean the kernel is sitting on an average of 6 MB of unusable memory. It would also mean that unloaded modules would create holes in that memory which would have to be managed.
