[PATCH v4.5 7/8] drm/i915: Introduce per-cgroup display boost setting

[Matt Roper]

Usually display-boosted contexts get treated as
I915_CONTEXT_MAX_USER_PRIORITY+1, which prioritizes them above regular
GPU contexts.  Now that we allow a much larger range of effective
priority values via per-cgroup priority offsets, a system administrator
may want more detailed control over how much a process should be boosted
by display operations (i.e., can a context from a cgroup with a low
priority offset still be display boosted above contexts from a cgroup
with a much higher priority offset?  or are come cgroups more important
than maintaining display rate?).

Cc: Chris Wilson <chris at chris-wilson.co.uk>
Signed-off-by: Matt Roper <matthew.d.roper at intel.com>
---
 drivers/gpu/drm/i915/i915_cgroup.c   | 17 +++++++++++++++++
 drivers/gpu/drm/i915/i915_drv.h      |  6 ++++++
 drivers/gpu/drm/i915/i915_request.h  |  1 +
 drivers/gpu/drm/i915/intel_display.c |  5 +++--
 include/uapi/drm/i915_drm.h          |  1 +
 5 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_cgroup.c b/drivers/gpu/drm/i915/i915_cgroup.c
index 0921d624f840..2bef8a5cac93 100644
--- a/drivers/gpu/drm/i915/i915_cgroup.c
+++ b/drivers/gpu/drm/i915/i915_cgroup.c
@@ -11,6 +11,7 @@
 
 struct i915_cgroup_data {
 	int priority_offset;
+	int display_boost;
 
 	struct kref ref;
 };
@@ -75,6 +76,8 @@ get_or_create_cgroup_data(struct drm_i915_private *dev_priv,
 			goto out;
 		}
 
+		priv->display_boost = I915_PRIORITY_DEFAULT_DISPBOOST;
+
 		kref_init(&priv->ref);
 		cgroup_priv_install(cgrp, dev_priv->cgroup_priv_key,
 				    &priv->ref);
@@ -151,6 +154,19 @@ i915_cgroup_setparam_ioctl(struct drm_device *dev,
 		}
 		break;
 
+	case I915_CGROUP_PARAM_DISPBOOST_PRIORITY:
+		if (req->value < I915_PRIORITY_MAX_DISPBOOST &&
+		    req->value > I915_PRIORITY_MIN) {
+			DRM_DEBUG_DRIVER("Setting cgroup display boost priority to %lld\n",
+					 req->value);
+			cgrpdata->display_boost = req->value;
+		} else {
+			DRM_DEBUG_DRIVER("Invalid cgroup display boost priority %lld\n",
+					 req->value);
+			ret = -EINVAL;
+		}
+		break;
+
 	default:
 		DRM_DEBUG_DRIVER("Invalid cgroup parameter %lld\n", req->param);
 		ret = -EINVAL;
@@ -186,5 +202,6 @@ int i915_cgroup_get_current_##name(struct drm_i915_private *dev_priv)	\
 }
 
 CGROUP_GET(prio_offset, priority_offset, 0)
+CGROUP_GET(dispboost, display_boost, I915_PRIORITY_DEFAULT_DISPBOOST);
 
 #undef CGROUP_GET
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 72e6cd7bfbae..bde58327b892 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2694,6 +2694,7 @@ int i915_cgroup_setparam_ioctl(struct drm_device *dev, void *data,
 			       struct drm_file *file);
 void i915_cgroup_shutdown(struct drm_i915_private *dev_priv);
 int i915_cgroup_get_current_prio_offset(struct drm_i915_private *dev_priv);
+int i915_cgroup_get_current_dispboost(struct drm_i915_private *dev_priv);
 #else
 static inline int
 i915_cgroup_init(struct drm_i915_private *dev_priv)
@@ -2715,6 +2716,11 @@ i915_cgroup_get_current_prio_offset(struct drm_i915_private *dev_priv)
 {
 	return 0;
 }
+static inline int
+i915_cgroup_get_current_dispboost(struct drm_i915_private *dev_priv)
+{
+	return I915_PRIORITY_DEFAULT_DISPBOOST;
+}
 #endif
 
 /* i915_drv.c */
diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
index cf7a7147daf3..db300d93fd08 100644
--- a/drivers/gpu/drm/i915/i915_request.h
+++ b/drivers/gpu/drm/i915/i915_request.h
@@ -90,6 +90,7 @@ enum {
 	/* Range reachable by combining user priority + cgroup offset */
 	I915_PRIORITY_MAX = 0x7fffff,
 	I915_PRIORITY_MIN = -I915_PRIORITY_MAX,
+	I915_PRIORITY_MAX_DISPBOOST = I915_PRIORITY_MAX + 1,
 
 	/* Special case priority values */
 	I915_PRIORITY_INVALID = INT_MIN,
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index b053a21f682b..1d0245e2fd75 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -12731,7 +12731,7 @@ intel_prepare_plane_fb(struct drm_plane *plane,
 	struct drm_framebuffer *fb = new_state->fb;
 	struct drm_i915_gem_object *obj = intel_fb_obj(fb);
 	struct drm_i915_gem_object *old_obj = intel_fb_obj(plane->state->fb);
-	int ret;
+	int boost, ret;
 
 	if (old_obj) {
 		struct drm_crtc_state *crtc_state =
@@ -12783,7 +12783,8 @@ intel_prepare_plane_fb(struct drm_plane *plane,
 
 	ret = intel_plane_pin_fb(to_intel_plane_state(new_state));
 
-	i915_gem_object_wait_priority(obj, 0, I915_PRIORITY_DEFAULT_DISPBOOST);
+	boost = i915_cgroup_get_current_dispboost(dev_priv);
+	i915_gem_object_wait_priority(obj, 0, boost);
 
 	mutex_unlock(&dev_priv->drm.struct_mutex);
 	i915_gem_object_unpin_pages(obj);
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 6b70f46d224e..ad454f121884 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -1727,6 +1727,7 @@ struct drm_i915_cgroup_param {
 	__u32 flags;
 	__u64 param;
 #define I915_CGROUP_PARAM_PRIORITY_OFFSET	0x1
+#define I915_CGROUP_PARAM_DISPBOOST_PRIORITY    0x2
 	__s64 value;
 };
 
-- 
2.14.3