On Fri, 05 Oct 2012, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> 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));
What is DRM_I915_HANGCHECK_PERIOD based on; specifically is it a strict
minimum value? Should round_jiffies_*up*_relative() be used instead?
BR,
Jani.
> }
> 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
>
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