[PATCH 07/28] drm/amdgpu: track ring state associated with a job
Alex Deucher
alexdeucher at gmail.com
Mon Jun 2 22:42:40 UTC 2025
On Mon, Jun 2, 2025 at 10:36 AM Christian König
<christian.koenig at amd.com> wrote:
>
> On 5/29/25 22:07, Alex Deucher wrote:
> > We need to know the wptr and sequence number associated
> > with a job so that we can re-emit the unprocessed state
> > after a ring reset. Pre-allocate storage space for
> > the ring buffer contents and add a helper to save off
> > the unprocessed state so that it can be re-emitted
> > after the queue is reset.
> >
> > Add a helper that ring reset callbacks can use to verify
> > that the ring has reset successfully and to reemit any
> > unprocessed ring contents from subsequent jobs.
> >
> > Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
> > ---
> > drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c | 12 ++++++
> > drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c | 6 +++
> > drivers/gpu/drm/amd/amdgpu/amdgpu_job.c | 5 ++-
> > drivers/gpu/drm/amd/amdgpu/amdgpu_job.h | 2 +
> > drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c | 46 +++++++++++++++++++++++
> > drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h | 8 ++++
> > 6 files changed, 78 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> > index 2f24a6aa13bf6..319548ac58820 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> > @@ -764,6 +764,18 @@ void amdgpu_fence_driver_force_completion(struct amdgpu_ring *ring)
> > amdgpu_fence_process(ring);
> > }
> >
> > +/**
> > + * amdgpu_fence_driver_seq_force_completion - force signal of specified sequence
> > + *
> > + * @ring: fence of the ring to signal
> > + *
> > + */
> > +void amdgpu_fence_driver_seq_force_completion(struct amdgpu_ring *ring, u32 seq)
> > +{
> > + amdgpu_fence_write(ring, seq);
> > + amdgpu_fence_process(ring);
> > +}
> > +
> > /*
> > * Common fence implementation
> > */
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
> > index 802743efa3b39..67df82d50a74a 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
> > @@ -306,6 +306,12 @@ int amdgpu_ib_schedule(struct amdgpu_ring *ring, unsigned int num_ibs,
> >
> > amdgpu_ring_ib_end(ring);
> > amdgpu_ring_commit(ring);
> > + /* This must be last for resets to work properly
> > + * as we need to save the wptr associated with this
> > + * job.
> > + */
> > + if (job)
> > + job->ring_wptr = ring->wptr;
>
> First of all such state should *absolutely* not be made part of the job. That belongs into the HW fence.
Done. Updated patches pushed here:
https://gitlab.freedesktop.org/agd5f/linux/-/commits/kq_resets?ref_type=heads
>
> Then we need to handle the case that one application submitted multiple jobs which potentially depend on each other.
>
> I think we should rather put this logic into amdgpu_device_enforce_isolation().
I'm not quite sure I understand what you are proposing. Is the idea
to track all of the jobs associated with a particular process and then
when we reset a queue, skip all of the ring contents associated with
those jobs and signal and set the error on all of their job fences?
What about cross ring dependencies?
Alex
>
> Regards,
> Christian.
>
>
> > return 0;
> > }
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
> > index a0fab947143b5..f0f752284b925 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
> > @@ -91,6 +91,7 @@ static enum drm_gpu_sched_stat amdgpu_job_timedout(struct drm_sched_job *s_job)
> > struct amdgpu_job *job = to_amdgpu_job(s_job);
> > struct amdgpu_task_info *ti;
> > struct amdgpu_device *adev = ring->adev;
> > + struct dma_fence *fence = &job->hw_fence;
> > int idx;
> > int r;
> >
> > @@ -154,8 +155,10 @@ static enum drm_gpu_sched_stat amdgpu_job_timedout(struct drm_sched_job *s_job)
> > else
> > is_guilty = true;
> >
> > - if (is_guilty)
> > + if (is_guilty) {
> > + amdgpu_ring_backup_unprocessed_jobs(ring, job->ring_wptr, fence->seqno);
> > dma_fence_set_error(&s_job->s_fence->finished, -ETIME);
> > + }
> >
> > r = amdgpu_ring_reset(ring, job->vmid);
> > if (!r) {
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h
> > index f2c049129661f..c2ed0edb5179d 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h
> > @@ -79,6 +79,8 @@ struct amdgpu_job {
> > /* enforce isolation */
> > bool enforce_isolation;
> > bool run_cleaner_shader;
> > + /* wptr for the job for resets */
> > + uint32_t ring_wptr;
> >
> > uint32_t num_ibs;
> > struct amdgpu_ib ibs[];
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
> > index 426834806fbf2..909b121d432cb 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
> > @@ -333,6 +333,12 @@ int amdgpu_ring_init(struct amdgpu_device *adev, struct amdgpu_ring *ring,
> > /* Initialize cached_rptr to 0 */
> > ring->cached_rptr = 0;
> >
> > + if (!ring->ring_backup) {
> > + ring->ring_backup = kvzalloc(ring->ring_size, GFP_KERNEL);
> > + if (!ring->ring_backup)
> > + return -ENOMEM;
> > + }
> > +
> > /* Allocate ring buffer */
> > if (ring->ring_obj == NULL) {
> > r = amdgpu_bo_create_kernel(adev, ring->ring_size + ring->funcs->extra_dw, PAGE_SIZE,
> > @@ -342,6 +348,7 @@ int amdgpu_ring_init(struct amdgpu_device *adev, struct amdgpu_ring *ring,
> > (void **)&ring->ring);
> > if (r) {
> > dev_err(adev->dev, "(%d) ring create failed\n", r);
> > + kvfree(ring->ring_backup);
> > return r;
> > }
> > amdgpu_ring_clear_ring(ring);
> > @@ -385,6 +392,8 @@ void amdgpu_ring_fini(struct amdgpu_ring *ring)
> > amdgpu_bo_free_kernel(&ring->ring_obj,
> > &ring->gpu_addr,
> > (void **)&ring->ring);
> > + kvfree(ring->ring_backup);
> > + ring->ring_backup = NULL;
> >
> > dma_fence_put(ring->vmid_wait);
> > ring->vmid_wait = NULL;
> > @@ -753,3 +762,40 @@ bool amdgpu_ring_sched_ready(struct amdgpu_ring *ring)
> >
> > return true;
> > }
> > +
> > +void amdgpu_ring_backup_unprocessed_jobs(struct amdgpu_ring *ring,
> > + u64 bad_wptr, u32 bad_seq)
> > +{
> > + unsigned int entries_to_copy = ring->wptr - bad_wptr;
> > + unsigned int idx, i;
> > +
> > + for (i = 0; i < entries_to_copy; i++) {
> > + idx = (bad_wptr + i) & ring->buf_mask;
> > + ring->ring_backup[i] = ring->ring[idx];
> > + }
> > + ring->ring_backup_entries_to_copy = entries_to_copy;
> > + ring->ring_backup_seq = bad_seq;
> > +}
> > +
> > +int amdgpu_ring_reemit_unprocessed_jobs(struct amdgpu_ring *ring)
> > +{
> > + unsigned int i;
> > + int r;
> > +
> > + /* signal the fence of the bad job */
> > + amdgpu_fence_driver_seq_force_completion(ring, ring->ring_backup_seq);
> > + /* verify that the ring is functional */
> > + r = amdgpu_ring_test_ring(ring);
> > + if (r)
> > + return r;
> > + /* re-emit the unprocessed ring contents */
> > + if (ring->ring_backup_entries_to_copy) {
> > + if (amdgpu_ring_alloc(ring, ring->ring_backup_entries_to_copy))
> > + return -ENOMEM;
> > + for (i = 0; i < ring->ring_backup_entries_to_copy; i++)
> > + amdgpu_ring_write(ring, ring->ring_backup[i]);
> > + amdgpu_ring_commit(ring);
> > + }
> > +
> > + return r;
> > +}
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
> > index b95b471107692..fd08449eee33f 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
> > @@ -132,6 +132,8 @@ extern const struct drm_sched_backend_ops amdgpu_sched_ops;
> > void amdgpu_fence_driver_clear_job_fences(struct amdgpu_ring *ring);
> > void amdgpu_fence_driver_set_error(struct amdgpu_ring *ring, int error);
> > void amdgpu_fence_driver_force_completion(struct amdgpu_ring *ring);
> > +void amdgpu_fence_driver_seq_force_completion(struct amdgpu_ring *ring,
> > + u32 seq);
> >
> > int amdgpu_fence_driver_init_ring(struct amdgpu_ring *ring);
> > int amdgpu_fence_driver_start_ring(struct amdgpu_ring *ring,
> > @@ -268,6 +270,9 @@ struct amdgpu_ring {
> >
> > struct amdgpu_bo *ring_obj;
> > uint32_t *ring;
> > + uint32_t *ring_backup;
> > + uint32_t ring_backup_seq;
> > + unsigned int ring_backup_entries_to_copy;
> > unsigned rptr_offs;
> > u64 rptr_gpu_addr;
> > volatile u32 *rptr_cpu_addr;
> > @@ -534,4 +539,7 @@ int amdgpu_ib_pool_init(struct amdgpu_device *adev);
> > void amdgpu_ib_pool_fini(struct amdgpu_device *adev);
> > int amdgpu_ib_ring_tests(struct amdgpu_device *adev);
> > bool amdgpu_ring_sched_ready(struct amdgpu_ring *ring);
> > +void amdgpu_ring_backup_unprocessed_jobs(struct amdgpu_ring *ring,
> > + u64 bad_wptr, u32 bad_seq);
> > +int amdgpu_ring_reemit_unprocessed_jobs(struct amdgpu_ring *ring);
> > #endif
>
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