Re: [RFC v3 0/5] Transparent on-demand struct page initialization embedded in the buddy allocator

Mike Travis
2013-08-13T18:04:07Z

On 8/13/2013 10:51 AM, Linus Torvalds wrote:
> by the time you can log in. And if it then takes another ten minutes
> until you have the full 16TB initialized, and some things might be a
> tad slower early on, does anybody really care? The machine will be up
> and running with plenty of memory, even if it may not be *all* the
> memory yet.

Before the patches adding memory took ~45 mins for 16TB and almost 2 hours
for 32TB. Adding it late sped up early boot but late insertion was still
very slow, where the full 32TB was still not fully inserted after an hour.
Doing it in parallel along with the memory hotplug lock per node, we got
it down to the 10-15 minute range.