[PATCH 6/6] drm/i915: Use trylock in shrinker for ggtt on bsw + bxt

[Maarten Lankhorst]

Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_shrinker.c | 13 +++++++++----
 drivers/gpu/drm/i915/gt/intel_gtt.c          |  5 ++++-
 drivers/gpu/drm/i915/i915_drv.h              |  1 +
 drivers/gpu/drm/i915/i915_gem.c              | 15 +++++++++++++--
 4 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c b/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
index 3e248d3bd869..3978a1695502 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
@@ -38,15 +38,17 @@ static bool can_release_pages(struct drm_i915_gem_object *obj)
 }
 
 static bool unsafe_drop_pages(struct drm_i915_gem_object *obj,
-			      unsigned long shrink)
+			      unsigned long shrink, bool trylock_ggtt)
 {
 	unsigned long flags;
 
 	flags = 0;
 	if (shrink & I915_SHRINK_ACTIVE)
-		flags = I915_GEM_OBJECT_UNBIND_ACTIVE;
+		flags |= I915_GEM_OBJECT_UNBIND_ACTIVE;
 	if (!(shrink & I915_SHRINK_BOUND))
-		flags = I915_GEM_OBJECT_UNBIND_TEST;
+		flags |= I915_GEM_OBJECT_UNBIND_TEST;
+	if (trylock_ggtt)
+		flags |= I915_GEM_OBJECT_UNBIND_GGTT_VM_TRYLOCK;
 
 	if (i915_gem_object_unbind(obj, flags) == 0)
 		return true;
@@ -115,6 +117,9 @@ i915_gem_shrink(struct i915_gem_ww_ctx *ww,
 	unsigned long count = 0;
 	unsigned long scanned = 0;
 	int err;
+	bool trylock_ggtt =
+		/* CHV + VTD workaround use stop_machine(), so can't lock the vm->mutex in the shrinker */
+		!ww && (IS_CHERRYVIEW(i915) || intel_ggtt_update_needs_vtd_wa(i915));
 
 	trace_i915_gem_shrink(i915, target, shrink);
 
@@ -203,7 +208,7 @@ i915_gem_shrink(struct i915_gem_ww_ctx *ww,
 			spin_unlock_irqrestore(&i915->mm.obj_lock, flags);
 
 			err = 0;
-			if (unsafe_drop_pages(obj, shrink)) {
+			if (unsafe_drop_pages(obj, shrink, trylock_ggtt)) {
 				/* May arrive from get_pages on another bo */
 				if (!ww) {
 					if (!i915_gem_object_trylock(obj))
diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.c b/drivers/gpu/drm/i915/gt/intel_gtt.c
index 96881e2bb228..df28bc75135d 100644
--- a/drivers/gpu/drm/i915/gt/intel_gtt.c
+++ b/drivers/gpu/drm/i915/gt/intel_gtt.c
@@ -132,7 +132,10 @@ void i915_address_space_init(struct i915_address_space *vm, int subclass)
 	 */
 	mutex_init(&vm->mutex);
 	lockdep_set_subclass(&vm->mutex, subclass);
-	i915_gem_shrinker_taints_mutex(vm->i915, &vm->mutex);
+
+	/* CHV + VTD workaround use stop_machine(), so can't lock the vm->mutex in the shrinker */
+	if (!(subclass == VM_CLASS_GGTT && (IS_CHERRYVIEW(vm->i915) || intel_ggtt_update_needs_vtd_wa(vm->i915))))
+		i915_gem_shrinker_taints_mutex(vm->i915, &vm->mutex);
 	dma_resv_init(&vm->resv);
 
 	GEM_BUG_ON(!vm->total);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 69e43bf91a15..f43bb1fb57a6 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1786,6 +1786,7 @@ int i915_gem_object_unbind(struct drm_i915_gem_object *obj,
 #define I915_GEM_OBJECT_UNBIND_ACTIVE BIT(0)
 #define I915_GEM_OBJECT_UNBIND_BARRIER BIT(1)
 #define I915_GEM_OBJECT_UNBIND_TEST BIT(2)
+#define I915_GEM_OBJECT_UNBIND_GGTT_VM_TRYLOCK BIT(3)
 
 void i915_gem_runtime_suspend(struct drm_i915_private *dev_priv);
 
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 96e6c982cb00..16757daa8f44 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -157,8 +157,19 @@ int i915_gem_object_unbind(struct drm_i915_gem_object *obj,
 		if (vma) {
 			ret = -EBUSY;
 			if (flags & I915_GEM_OBJECT_UNBIND_ACTIVE ||
-			    !i915_vma_is_active(vma))
-				ret = i915_vma_unbind(vma);
+			    !i915_vma_is_active(vma)) {
+				if (i915_is_ggtt(vma->vm) &&
+				    flags & I915_GEM_OBJECT_UNBIND_GGTT_VM_TRYLOCK) {
+					if (mutex_trylock(&vma->vm->mutex)) {
+						ret = __i915_vma_unbind(vma);
+						mutex_unlock(&vma->vm->mutex);
+					} else {
+						ret = -EBUSY;
+					}
+				} else {
+					ret = i915_vma_unbind(vma);
+				}
+			}
 
 			__i915_vma_put(vma);
 		}
-- 
2.31.0