1 files changed, 39 insertions, 24 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem_evict.c b/drivers/gpu/drm/i915/i915_gem_evict.c
index 4df039ef2ce3..e161d383b526 100644
--- a/drivers/gpu/drm/i915/i915_gem_evict.c
+++ b/drivers/gpu/drm/i915/i915_gem_evict.c
@@ -33,21 +33,20 @@
 #include "intel_drv.h"
 #include "i915_trace.h"
 
-static bool ggtt_is_idle(struct drm_i915_private *dev_priv)
+static bool ggtt_is_idle(struct drm_i915_private *i915)
 {
-        struct i915_ggtt *ggtt = &dev_priv->ggtt;
-        struct intel_engine_cs *engine;
-        enum intel_engine_id id;
+       struct intel_engine_cs *engine;
+       enum intel_engine_id id;
 
-        for_each_engine(engine, dev_priv, id) {
-                struct intel_timeline *tl;
+       if (i915->gt.active_requests)
+               return false;
 
-                tl = &ggtt->base.timeline.engine[engine->id];
-                if (i915_gem_active_isset(&tl->last_request))
-                        return false;
-        }
+       for_each_engine(engine, i915, id) {
+               if (engine->last_retired_context != i915->kernel_context)
+                       return false;
+       }
 
-        return true;
+       return true;
 }
 
 static int ggtt_flush(struct drm_i915_private *i915)
@@ -157,7 +156,8 @@ i915_gem_evict_something(struct i915_address_space *vm,
                                     min_size, alignment, cache_level,
                                     start, end, mode);
 
-        /* Retire before we search the active list. Although we have
+        /*
+         * Retire before we search the active list. Although we have
          * reasonable accuracy in our retirement lists, we may have
          * a stray pin (preventing eviction) that can only be resolved by
          * retiring.
@@ -182,7 +182,8 @@ search_again:
                 BUG_ON(ret);
         }
 
-        /* Can we unpin some objects such as idle hw contents,
+        /*
+         * Can we unpin some objects such as idle hw contents,
          * or pending flips? But since only the GGTT has global entries
          * such as scanouts, rinbuffers and contexts, we can skip the
          * purge when inspecting per-process local address spaces.
@@ -190,19 +191,33 @@ search_again:
         if (!i915_is_ggtt(vm) || flags & PIN_NONBLOCK)
                 return -ENOSPC;
 
-        if (ggtt_is_idle(dev_priv)) {
-                /* If we still have pending pageflip completions, drop
-                 * back to userspace to give our workqueues time to
-                 * acquire our locks and unpin the old scanouts.
-                 */
-                return intel_has_pending_fb_unpin(dev_priv) ? -EAGAIN : -ENOSPC;
-        }
+        /*
+         * Not everything in the GGTT is tracked via VMA using
+         * i915_vma_move_to_active(), otherwise we could evict as required
+         * with minimal stalling. Instead we are forced to idle the GPU and
+         * explicitly retire outstanding requests which will then remove
+         * the pinning for active objects such as contexts and ring,
+         * enabling us to evict them on the next iteration.
+         *
+         * To ensure that all user contexts are evictable, we perform
+         * a switch to the perma-pinned kernel context. This all also gives
+         * us a termination condition, when the last retired context is
+         * the kernel's there is no more we can evict.
+         */
+        if (!ggtt_is_idle(dev_priv)) {
+                ret = ggtt_flush(dev_priv);
+                if (ret)
+                        return ret;
 
-        ret = ggtt_flush(dev_priv);
-        if (ret)
-                return ret;
+                goto search_again;
+        }
 
-        goto search_again;
+        /*
+         * If we still have pending pageflip completions, drop
+         * back to userspace to give our workqueues time to
+         * acquire our locks and unpin the old scanouts.
+         */
+        return intel_has_pending_fb_unpin(dev_priv) ? -EAGAIN : -ENOSPC;
 
 found:
         /* drm_mm doesn't allow any other other operations while