[Intel-gfx] [PATCH] drm/i915: Watch out for idling during i915_gem_evict_something

[Chris Wilson]

Quoting Mika Kuoppala (2020-05-12 11:39:31)
> Chris Wilson <chris at chris-wilson.co.uk> writes:
> 
> > i915_gem_evict_something() is charged with finding a slot within the GTT
> > that we may reuse. Since our goal is not to stall, we first look for a
> > slot that only overlaps idle vma. To this end, on the first pass we move
> > any active vma to the end of the search list. However, we only stopped
> > moving active vma after we see the first active vma twice. If during the
> > search, that first active vma completed, we would not notice and keep on
> > extending the search list.
> >
> > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/1746
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> > Cc: <stable at vger.kernel.org> # v5.5+
> 
> Only thing I would change is tune up the subject line.
> It fixes a possible busy loop in eviction so I feel 'watch out' is not
> strong enough for my liking.

Duck and cover for the idling is a-coming!
-Chris