On Wed, Apr 13, 2022 at 12:36:11PM +0200, David Hildenbrand wrote: > On 12.04.22 18:08, Dave Hansen wrote: > > On 4/12/22 01:15, David Hildenbrand wrote: > > > > The other option might be to tie this all to DEFERRED_STRUCT_PAGE_INIT. > > Have the rule that everything that gets a 'struct page' must be > > accepted. If you want to do delayed acceptance, you do it via > > DEFERRED_STRUCT_PAGE_INIT. > > That could also be an option, yes. At least being able to chose would be > good. But IIRC, DEFERRED_STRUCT_PAGE_INIT will still make the system get > stuck during boot and wait until everything was accepted. The deferred page init runs multithreaded, so guest with SMP will be stuck for less time. > I see the following variants: > > 1) Slow boot; after boot, all memory is already accepted. > 2) Fast boot; after boot, all memory will slowly but steadily get > accepted in the background. After a while, all memory is accepted and > can be signaled to user space. > 3) Fast boot; after boot, memory gets accepted on demand. This is what > we have in this series. > > I somehow don't quite like 3), but with deferred population in the > hypervisor, it might just make sense. IMHO, deferred population in hypervisor will be way more complex than this series with similar "visible" performance. -- Sincerely yours, Mike.
