[PATCH 2/6] drm/i915: Try hard to bind the context

[Chris Wilson]

It is not acceptable for context pinning to fail with -ENOSPC as we
should always be able to make space in the GGTT. The only reason we may
fail is that other "temporary" context pins are reserving their space
and we need to wait for an available slot.

Closes: https://gitlab.freedesktop.org/drm/intel/issues/676
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem_gtt.c | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 10b3d6d44045..7e20c6f62cd5 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -1934,9 +1934,24 @@ int gen6_ppgtt_pin(struct i915_ppgtt *base)
 	 * size. We allocate at the top of the GTT to avoid fragmentation.
 	 */
 	if (!atomic_read(&ppgtt->pin_count)) {
-		err = i915_vma_pin(ppgtt->vma,
-				   0, GEN6_PD_ALIGN,
-				   PIN_GLOBAL | PIN_HIGH);
+		do {
+			struct i915_address_space *vm = ppgtt->vma->vm;
+
+			err = i915_vma_pin(ppgtt->vma,
+					   0, GEN6_PD_ALIGN,
+					   PIN_GLOBAL | PIN_HIGH);
+			if (err != -ENOSPC)
+				break;
+
+			/* We don't take no for an answer! */
+			err = mutex_lock_interruptible(&vm->mutex);
+			if (err == 0) {
+				err = i915_gem_evict_vm(vm);
+				mutex_unlock(&vm->mutex);
+			}
+			if (err)
+				break;
+		} while (1);
 	}
 	if (!err)
 		atomic_inc(&ppgtt->pin_count);
-- 
2.24.0