drm/i915: Drain freed objects for mmap space exhaustion

As we now use a deferred free queue for objects, simply retiring the
active objects is not enough to immediately free them and recover their
mmap space - we must now also drain the freed object list.

Fixes: fbbd37b36fa5 ("drm/i915: Move object release to a freelist + worker"
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: <drm-intel-fixes@lists.freedesktop.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20170106152240.5793-3-chris@chris-wilson.co.uk
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index a2b8a74168d7288adf1cc1d4a75fa31c7e18da2d..ed3cd1a5f9bbf99e58c375d63c5db4d49ff76dfb 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2090,23 +2090,21 @@ static int i915_gem_object_create_mmap_offset(struct drm_i915_gem_object *obj)
        int err;
 
        err = drm_gem_create_mmap_offset(&obj->base);
-       if (!err)
+       if (likely(!err))
                return 0;
 
-       /* We can idle the GPU locklessly to flush stale objects, but in order
-        * to claim that space for ourselves, we need to take the big
-        * struct_mutex to free the requests+objects and allocate our slot.
-        */
-       err = i915_gem_wait_for_idle(dev_priv, I915_WAIT_INTERRUPTIBLE);
-       if (err)
-               return err;
+       /* Attempt to reap some mmap space from dead objects */
+       do {
+               err = i915_gem_wait_for_idle(dev_priv, I915_WAIT_INTERRUPTIBLE);
+               if (err)
+                       break;
 
-       err = i915_mutex_lock_interruptible(&dev_priv->drm);
-       if (!err) {
-               i915_gem_retire_requests(dev_priv);
+               i915_gem_drain_freed_objects(dev_priv);
                err = drm_gem_create_mmap_offset(&obj->base);
-               mutex_unlock(&dev_priv->drm.struct_mutex);
-       }
+               if (!err)
+                       break;
+
+       } while (flush_delayed_work(&dev_priv->gt.retire_work));
 
        return err;
 }