drm/i915: Introduce DRM_I915_THROTTLE_JIFFIES
As Daniel commented on
commit b7ffe1362c5f468b853223acc9268804aa92afc8
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date: Mon Apr 27 13:41:24 2015 +0100
drm/i915: Free RPS boosts for all laggards
it is better to be explicit when sharing hardcoded values such as
throttle/boost timeouts. Make it so!
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 44d592f..1038f5c 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -279,6 +279,12 @@
struct {
spinlock_t lock;
struct list_head request_list;
+/* 20ms is a fairly arbitrary limit (greater than the average frame time)
+ * chosen to prevent the CPU getting more than a frame ahead of the GPU
+ * (when using lax throttling for the frontbuffer). We also use it to
+ * offer free GPU waitboosts for severely congested workloads.
+ */
+#define DRM_I915_THROTTLE_JIFFIES msecs_to_jiffies(20)
} mm;
struct idr context_idr;
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 0ce3e4b..cc206f1 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4239,7 +4239,7 @@
{
struct drm_i915_private *dev_priv = dev->dev_private;
struct drm_i915_file_private *file_priv = file->driver_priv;
- unsigned long recent_enough = jiffies - msecs_to_jiffies(20);
+ unsigned long recent_enough = jiffies - DRM_I915_THROTTLE_JIFFIES;
struct drm_i915_gem_request *request, *target = NULL;
unsigned reset_counter;
int ret;
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 84809a6..55d9931 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -4158,7 +4158,7 @@
/* Force a RPS boost (and don't count it against the client) if
* the GPU is severely congested.
*/
- if (rps && time_after(jiffies, submitted + msecs_to_jiffies(20)))
+ if (rps && time_after(jiffies, submitted + DRM_I915_THROTTLE_JIFFIES))
rps = NULL;
mutex_lock(&dev_priv->rps.hw_lock);