On Thu, Apr 26, 2012 at 04:03:06PM -0700, Ben Widawsky wrote:
> Insert a wait parameter in the code so we can possibly timeout on a
> seqno wait if need be. The code should be functionally the same as
> before because all the callers will continue to retry if an arbitrary
> timeout elapses.
>
> We'd like to have nanosecond granularity, but the only way to do this is
> with hrtimer, and that doesn't fit well with the needs of this code.
>
> Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
I have to admit, I'm a bit unhappy with this swiss-army-tool wait_seqno
and what it looks like. What about copy&pasting __wait_seqno_timeout,
which is always interruptible?
-Daniel
> ---
> drivers/gpu/drm/i915/i915_gem.c | 58 +++++++++++++++++++++++++++++++--------
> 1 file changed, 46 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 0ae1a73..f054439 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -1820,10 +1820,23 @@ i915_gem_retire_work_handler(struct work_struct *work)
> }
>
> static int __wait_seqno(struct intel_ring_buffer *ring, u32 seqno,
> - bool interruptible)
> + bool interruptible, long *usecs)
> {
> drm_i915_private_t *dev_priv = ring->dev->dev_private;
> - int ret = 0;
> + bool wait_forever = false;
> + long timeout, end;
> +
> + if (usecs == NULL || ((*usecs) < 0)) {
> + wait_forever = true;
> + timeout = msecs_to_jiffies(100);
> + } else
> + timeout = usecs_to_jiffies(*usecs);
> +
> + if (i915_seqno_passed(ring->get_seqno(ring), seqno))
> + return 0;
> +
> + if (WARN_ON(!ring->irq_get(ring)))
> + return -ENODEV;
>
> if (i915_seqno_passed(ring->get_seqno(ring), seqno))
> return 0;
> @@ -1836,17 +1849,40 @@ static int __wait_seqno(struct intel_ring_buffer *ring, u32 seqno,
> (i915_seqno_passed(ring->get_seqno(ring), seqno) || \
> atomic_read(&dev_priv->mm.wedged))
>
> + trace_i915_gem_request_wait_begin(ring, seqno);
> +again:
> if (interruptible)
> - ret = wait_event_interruptible(ring->irq_queue,
> - EXIT_COND);
> + end = wait_event_interruptible_timeout(ring->irq_queue,
> + EXIT_COND,
> + timeout);
> else
> - wait_event(ring->irq_queue, EXIT_COND);
> + end = wait_event_timeout(ring->irq_queue, EXIT_COND, timeout);
> +#undef EXIT_COND
> +
> + if (atomic_read(&dev_priv->mm.wedged))
> + end = -EAGAIN;
> +
> + if (end == 0 && wait_forever)
> + goto again;
>
> - ring->irq_put(ring);
> trace_i915_gem_request_wait_end(ring, seqno);
> -#undef EXIT_COND
> + ring->irq_put(ring);
>
> - return ret;
> + if (!wait_forever) {
> + BUG_ON(end == 0);
> + *usecs = jiffies_to_usecs(timeout - end);
> + }
> +
> + switch (end) {
> + case -EAGAIN: /* Wedged */
> + case -ERESTARTSYS: /* Signal */
> + return (int)end;
> + case 0: /* Tiemout */
> + return -ETIME;
> + default: /* Completed */
> + WARN_ON(end < 0); /* We're not aware of other errors */
> + return 0;
> + }
> }
>
> /**
> @@ -1891,9 +1927,7 @@ i915_wait_request(struct intel_ring_buffer *ring,
> seqno = request->seqno;
> }
>
> - ret = __wait_seqno(ring, seqno, dev_priv->mm.interruptible);
> - if (atomic_read(&dev_priv->mm.wedged))
> - ret = -EAGAIN;
> + ret = __wait_seqno(ring, seqno, dev_priv->mm.interruptible, NULL);
>
> return ret;
> }
> @@ -2981,7 +3015,7 @@ i915_gem_ring_throttle(struct drm_device *dev, struct drm_file *file)
> if (seqno == 0)
> return 0;
>
> - ret = __wait_seqno(ring, seqno, true);
> + ret = __wait_seqno(ring, seqno, true, NULL);
> if (ret == 0)
> queue_delayed_work(dev_priv->wq, &dev_priv->mm.retire_work, 0);
>
> --
> 1.7.10
>
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> Intel-gfx at lists.freedesktop.org
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--
Daniel Vetter
Mail: daniel at ffwll.ch
Mobile: +41 (0)79 365 57 48
