On 03.12.20 11:51, Paul Menzel wrote: > Dear Feng, > > > I am trying to reduce the startup time of Debian’s Linux 5.9.9 on a > Intel Kaby Lake system with 32 GB of memory (TUXEDO Book BU1406 (Clevo > N240BU)). On your Linux Plumbers Conference 2019 slides of your talk > *Linux Kernel Fastboot On the Way* [1], you mention *Deferred Memory Init*: > >> Deferred Memory Init >> >> • 8GB RAM’s initialization costs 100+ ms >> • In early boot phase, we don’t need that much memory >> • Utilize the memory hotplug feature >> • “mem=4096m” in cmdline to only init 2 GB >> • Use systemd service to add rest memory in parallel Uh, that sounds very wrong and flawed. Even if you would be adding+onlining memory in parallel, memory hotplug/onlining code runs strictly sequential. This does not work. And I question this approach in general. We do have deferred meminit in the kernel during boot that can initialize memory in parallel. -- Thanks, David / dhildenb
