Re: Guaranteed allocation of huge pages (1G) using movablecore=N doesn't seem to work at all

From: Michal Hocko
Date: Mon Nov 06 2017 - 08:05:20 EST


On Sat 04-11-17 11:55:14, Maxim Levitsky wrote:
> Hi!
>
> My system has 64G of ram and I want to create 32 1G huge pages to use
> in KVM virtualization,
> on demand, only when VM is running.
>
> So I booted the kernel with
> 'hugepagesz=1G hugepages=0 default_hugepagesz=1G movablecore=40G'

Why do you think movablecore will help you? Giga pages are not
migrateable and as such they do not end up on movable zones.

I have recently changed the code to reflect that reality because
allowing giga pages to consume movable zone simply breaks memory
hotplug.
--
Michal Hocko
SUSE Labs