Quoting Mika Kuoppala (2020-05-12 11:39:31)
Chris Wilson chris@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@chris-wilson.co.uk Cc: Tvrtko Ursulin tvrtko.ursulin@intel.com Cc: stable@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