Re: [PATCH] hugetlb: Add nohugepages parameter to prevent hugepages creation

From: Guilherme G. Piccoli
Date: Tue Oct 15 2019 - 09:58:43 EST

On 10/15/19 9:18 AM, Michal Hocko wrote:
I do agree with Qian Cai here. Kdump kernel requires a very tailored
environment considering it is running in a very restricted
configuration. The hugetlb pre-allocation sounds like a tooling problem
and should be fixed at that layer.

Hi Michal, thanks for your response. Can you suggest me a current way of preventing hugepages for being created, using userspace? The goal for this patch is exactly this, introduce such a way.

As I've said before, Ubuntu kdump rely on rootfs mounting and there's no official statement or documentation that say it's wrong to do this way - although I agree initrd-only approach is more safe. But since Ubuntu kdump rely on rootfs mount, we couldn't find a way to effectively prevent the creation of hugepages completely, hence we tried to introduce one.