drm/i915/gem: Protect used framebuffers from casual eviction

In the shrinker, we protect framebuffers from light reclaim as we
typically expect framebuffers to be reused in the near future (and with
low latency requirements). We can apply the same logic to the GGTT
eviction and defer framebuffers to the second pass only used if the
caller is desperate enough to wait for space to become available.
In most cases, the caller will use a smaller partial vma instead of
trying to force the object into the GGTT if doing so will cause other
users to be evicted.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210119214336.1463-5-chris@chris-wilson.co.uk

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/display/intel_frontbuffer.c b/drivers/gpu/drm/i915/display/intel_frontbuffer.c
index d898b370d7a4..7b38eee9980f 100644
--- a/drivers/gpu/drm/i915/display/intel_frontbuffer.c
+++ b/drivers/gpu/drm/i915/display/intel_frontbuffer.c
@@ -225,8 +225,10 @@ static void frontbuffer_release(struct kref *ref)
 	struct i915_vma *vma;
 
 	spin_lock(&obj->vma.lock);
-	for_each_ggtt_vma(vma, obj)
+	for_each_ggtt_vma(vma, obj) {
+		i915_vma_clear_scanout(vma);
 		vma->display_alignment = I915_GTT_MIN_ALIGNMENT;
+	}
 	spin_unlock(&obj->vma.lock);
 
 	RCU_INIT_POINTER(obj->frontbuffer, NULL);