Re: [PATCH 10/17] prmem: documentation

From: Dave Hansen
Date: Tue Oct 30 2018 - 14:03:54 EST

On 10/30/18 10:58 AM, Matthew Wilcox wrote:
> Does this satisfy Igor's requirements? We wouldn't be able to
> copy_to/from_user() while rare_mm was active. I think that's a feature
> though! It certainly satisfies my interests (kernel code be able to
> mark things as dynamically-allocated-and-read-only-after-initialisation)

It has to be more than copy_to/from_user(), though, I think.

rare_modify(q) either has to preempt_disable(), or we need to teach the
context-switching code when and how to switch in/out of the rare_mm.
preempt_disable() would also keep us from sleeping.