[Intel-gfx] [PATCH 1/3] drm/i915: Only update the current userptr worker

[Chris Wilson]

On Fri, Jul 03, 2015 at 12:48:03PM +0200, Michał Winiarski wrote:
> On Tue, Jun 30, 2015 at 05:55:31PM +0100, Chris Wilson wrote:
> > The userptr worker allows for a slight race condition where upon there
> > may two or more threads calling get_user_pages for the same object. When
> > we have the array of pages, then we serialise the update of the object.
> > However, the worker should only overwrite the obj->userptr.work pointer
> > if and only if it is the active one. Currently we clear it for a
> > secondary worker with the effect that we may rarely force a second
> > lookup.
> > 
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> 
> Whole series:
> Tested-by: Michał Winiarski <michal.winiarski at intel.com>

That reminds me there was a refleak in patch 3 if a second
invalidate-range notification before the first's worker had run (we
would take the ref for the active mo, but since the worker was queued,
it would still only run once and not drop our new ref.)
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre