[Intel-gfx] [CI 04/20] drm/i915: Remove the dedicated hangcheck workqueue

[Chris Wilson]

On Fri, May 20, 2016 at 01:07:29PM +0100, Tvrtko Ursulin wrote:
> 
> On 19/05/16 14:13, Chris Wilson wrote:
> >On Thu, May 19, 2016 at 01:50:51PM +0100, Tvrtko Ursulin wrote:
> >>
> >>On 19/05/16 12:32, Chris Wilson wrote:
> >>>The queue only ever contains at most one item and has no special flags.
> >>>It is just a very simple wrapper around the system-wq - a complication
> >>>with no benefits.
> >>
> >>How much time do we take in the reset case - is it acceptable to do
> >>that work from the system wq?
> >
> >Hangcheck is a handful of register reads and some pointer chasing per
> >engine. (There is a seqno_barrier in there which may be reasonably
> >expensive but not a cpu hog). The error capture is run from the
> >hangcheck context - and that is no small task (especially if we ever
> >apply the object compression patches), but for safety we need to call
> >stop_machine() so it really doesn't matter at that point.
> 
> I don't see a stop_machine? So until there is one, using the system
> wq is a bit impolite in the error capture state, agreed?

It's in the queue to fix the odd oops we get during capture.

You'd be happy with system_long_wq in the meantime?
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre