Re: [RFC PATCH for 4.18 12/23] cpu_opv: Provide cpu_opv system call (v7)

From: Linus Torvalds
Date: Thu Apr 12 2018 - 15:43:38 EST


On Thu, Apr 12, 2018 at 12:27 PM, Mathieu Desnoyers
<mathieu.desnoyers@xxxxxxxxxxxx> wrote:
> The cpu_opv system call executes a vector of operations on behalf of
> user-space on a specific CPU with preemption disabled. It is inspired
> by readv() and writev() system calls which take a "struct iovec"
> array as argument.

Do we really want the page pinning?

This whole cpu_opv thing is the most questionable part of the series,
and the page pinning is the most questionable part of cpu_opv for me.

Can we plan on merging just the plain rseq parts *without* this all
first, and then see the cpu_opv thing as a "maybe future expansion"
part.

I think that would make Andy happier too.

Linus