Re: [PATCH 2/2] drm/i915: Use rcu instead of stop_machine in set_wedged

[Peter Zijlstra]

On Fri, Oct 06, 2017 at 12:12:41PM +0200, Thomas Gleixner wrote:
> So if you don't have a compelling technical reason to
> use it, then it _is_ the wrong tool.

This. stop_machine() effectively takes down _all_ CPUs for the duration
of your callback. That is something you really should avoid at pretty
much any cost.