[PATCH 2/5] drm/amdgpu: add ring soft recovery v2

[Alex Deucher]

On Wed, Aug 22, 2018 at 6:05 AM Christian König
<ckoenig.leichtzumerken at gmail.com> wrote:
>
> Instead of hammering hard on the GPU try a soft recovery first.
>
> v2: reorder code a bit
>
> Signed-off-by: Christian König <christian.koenig at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_job.c  |  6 ++++++
>  drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c | 24 ++++++++++++++++++++++++
>  drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h |  4 ++++
>  3 files changed, 34 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
> index 265ff90f4e01..d93e31a5c4e7 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
> @@ -33,6 +33,12 @@ static void amdgpu_job_timedout(struct drm_sched_job *s_job)
>         struct amdgpu_ring *ring = to_amdgpu_ring(s_job->sched);
>         struct amdgpu_job *job = to_amdgpu_job(s_job);
>
> +       if (amdgpu_ring_soft_recovery(ring, job->vmid, s_job->s_fence->parent)) {
> +               DRM_ERROR("ring %s timeout, but soft recovered\n",
> +                         s_job->sched->name);
> +               return;
> +       }

I think we should still bubble up the error to userspace even if we
can recover.  Data is lost when the wave is killed.  We should treat
it like a GPU reset.

Alex

> +
>         DRM_ERROR("ring %s timeout, signaled seq=%u, emitted seq=%u\n",
>                   job->base.sched->name, atomic_read(&ring->fence_drv.last_seq),
>                   ring->fence_drv.sync_seq);
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
> index 5dfd26be1eec..c045a4e38ad1 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
> @@ -383,6 +383,30 @@ void amdgpu_ring_emit_reg_write_reg_wait_helper(struct amdgpu_ring *ring,
>         amdgpu_ring_emit_reg_wait(ring, reg1, mask, mask);
>  }
>
> +/**
> + * amdgpu_ring_soft_recovery - try to soft recover a ring lockup
> + *
> + * @ring: ring to try the recovery on
> + * @vmid: VMID we try to get going again
> + * @fence: timedout fence
> + *
> + * Tries to get a ring proceeding again when it is stuck.
> + */
> +bool amdgpu_ring_soft_recovery(struct amdgpu_ring *ring, unsigned int vmid,
> +                              struct dma_fence *fence)
> +{
> +       ktime_t deadline = ktime_add_us(ktime_get(), 1000);
> +
> +       if (!ring->funcs->soft_recovery)
> +               return false;
> +
> +       while (!dma_fence_is_signaled(fence) &&
> +              ktime_to_ns(ktime_sub(deadline, ktime_get())) > 0)
> +               ring->funcs->soft_recovery(ring, vmid);
> +
> +       return dma_fence_is_signaled(fence);
> +}
> +
>  /*
>   * Debugfs info
>   */
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
> index 409fdd9b9710..9cc239968e40 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
> @@ -168,6 +168,8 @@ struct amdgpu_ring_funcs {
>         /* priority functions */
>         void (*set_priority) (struct amdgpu_ring *ring,
>                               enum drm_sched_priority priority);
> +       /* Try to soft recover the ring to make the fence signal */
> +       void (*soft_recovery)(struct amdgpu_ring *ring, unsigned vmid);
>  };
>
>  struct amdgpu_ring {
> @@ -260,6 +262,8 @@ void amdgpu_ring_fini(struct amdgpu_ring *ring);
>  void amdgpu_ring_emit_reg_write_reg_wait_helper(struct amdgpu_ring *ring,
>                                                 uint32_t reg0, uint32_t val0,
>                                                 uint32_t reg1, uint32_t val1);
> +bool amdgpu_ring_soft_recovery(struct amdgpu_ring *ring, unsigned int vmid,
> +                              struct dma_fence *fence);
>
>  static inline void amdgpu_ring_clear_ring(struct amdgpu_ring *ring)
>  {
> --
> 2.14.1
>
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