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

[Chris Wilson]

Quoting Chris Wilson (2020-05-09 12:52:17)
> 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

Fixes: 2850748ef876 ("drm/i915: Pull i915_vma_pin under the vm->mutex")
Fixes: b1e3177bd1d8 ("drm/i915: Coordinate i915_active with its own mutex")

> 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+