[Intel-gfx] [PATCH 1/2] drm/i915: Align the hangcheck wakeup to the nearest second

[Chris Wilson]

round_jiffies() aligns the wakeup time to the nearest second in order to
batch wakeups and reduce system load, which is useful for unimportant
coarse timers like our hangcheck.

Suggested-by: Arjan van de Ven <arjan at linux.intel.com>
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Arjan van de Ven <arjan at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h |    1 +
 drivers/gpu/drm/i915/i915_gem.c |    3 +--
 drivers/gpu/drm/i915/i915_irq.c |    5 ++---
 3 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index d8043af..f79c664 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -460,6 +460,7 @@ typedef struct drm_i915_private {
 
 	/* For hangcheck timer */
 #define DRM_I915_HANGCHECK_PERIOD 1500 /* in ms */
+#define DRM_I915_HANGCHECK_JIFFIES msecs_to_jiffies(DRM_I915_HANGCHECK_PERIOD)
 	struct timer_list hangcheck_timer;
 	int hangcheck_count;
 	uint32_t last_acthd[I915_NUM_RINGS];
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index c78f8e3..8e05d53 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2151,8 +2151,7 @@ i915_add_request(struct intel_ring_buffer *ring,
 	if (!dev_priv->mm.suspended) {
 		if (i915_enable_hangcheck) {
 			mod_timer(&dev_priv->hangcheck_timer,
-				  jiffies +
-				  msecs_to_jiffies(DRM_I915_HANGCHECK_PERIOD));
+				  round_jiffies_relative(DRM_I915_HANGCHECK_JIFFIES));
 		}
 		if (was_empty) {
 			queue_delayed_work(dev_priv->wq,
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index e18e56b..67dc487 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -353,8 +353,7 @@ static void notify_ring(struct drm_device *dev,
 	if (i915_enable_hangcheck) {
 		dev_priv->hangcheck_count = 0;
 		mod_timer(&dev_priv->hangcheck_timer,
-			  jiffies +
-			  msecs_to_jiffies(DRM_I915_HANGCHECK_PERIOD));
+			  round_jiffies_relative(DRM_I915_HANGCHECK_JIFFIES));
 	}
 }
 
@@ -1787,7 +1786,7 @@ void i915_hangcheck_elapsed(unsigned long data)
 repeat:
 	/* Reset timer case chip hangs without another request being added */
 	mod_timer(&dev_priv->hangcheck_timer,
-		  jiffies + msecs_to_jiffies(DRM_I915_HANGCHECK_PERIOD));
+		  round_jiffies_relative(DRM_I915_HANGCHECK_JIFFIES));
 }
 
 /* drm_dma.h hooks
-- 
1.7.10.4