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

[Marek Olšák]

On Wed, Aug 22, 2018 at 12:56 PM Alex Deucher <alexdeucher at gmail.com> wrote:
>
> 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.

Yes, please increment gpu_reset_counter, so that we are compliant with
OpenGL. Being able to recover from infinite loops is great, but test
suites also expect this to be properly reported to userspace via the
per-context query.

Also please bump the deadline to 1 second. Even you if you kill all
shaders, the IB can also contain CP DMA, which may take longer than 1
ms.

Marek

Marek

>
> 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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