On Thu Aug 05, 2021 at 05:13:22PM -0400, Andrey Grodzovsky wrote:
>
> On 2021-08-05 4:31 a.m., Jingwen Chen wrote:
> > From: Jack Zhang <Jack.Zhang1@xxxxxxx>
> >
> > Why: Previously hw fence is alloced separately with job.
> > It caused historical lifetime issues and corner cases.
> > The ideal situation is to take fence to manage both job
> > and fence's lifetime, and simplify the design of gpu-scheduler.
> >
> > How:
> > We propose to embed hw_fence into amdgpu_job.
> > 1. We cover the normal job submission by this method.
> > 2. For ib_test, and submit without a parent job keep the
> > legacy way to create a hw fence separately.
> > v2:
> > use AMDGPU_FENCE_FLAG_EMBED_IN_JOB_BIT to show that the fence is
> > embeded in a job.
> >
> > Signed-off-by: Jingwen Chen <Jingwen.Chen2@xxxxxxx>
> > Signed-off-by: Jack Zhang <Jack.Zhang7@xxxxxxxxxxx>
> > ---
> > drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c | 1 -
> > drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c | 2 +-
> > drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c | 63 ++++++++++++++++-----
> > drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c | 2 +-
> > drivers/gpu/drm/amd/amdgpu/amdgpu_job.c | 35 ++++++++----
> > drivers/gpu/drm/amd/amdgpu/amdgpu_job.h | 4 +-
> > drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h | 5 +-
> > drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 2 +-
> > 8 files changed, 84 insertions(+), 30 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c
> > index 7b46ba551cb2..3003ee1c9487 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c
> > @@ -714,7 +714,6 @@ int amdgpu_amdkfd_submit_ib(struct kgd_dev *kgd, enum kgd_engine_type engine,
> > ret = dma_fence_wait(f, false);
> > err_ib_sched:
> > - dma_fence_put(f);
> > amdgpu_job_free(job);
> > err:
> > return ret;
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
> > index 536005bff24a..277128846dd1 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
> > @@ -1414,7 +1414,7 @@ static void amdgpu_ib_preempt_mark_partial_job(struct amdgpu_ring *ring)
> > continue;
> > }
> > job = to_amdgpu_job(s_job);
> > - if (preempted && job->fence == fence)
> > + if (preempted && (&job->hw_fence) == fence)
> > /* mark the job as preempted */
> > job->preemption_status |= AMDGPU_IB_PREEMPTED;
> > }
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> > index 7495911516c2..5e29d797a265 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> > @@ -129,30 +129,46 @@ static u32 amdgpu_fence_read(struct amdgpu_ring *ring)
> > *
> > * @ring: ring the fence is associated with
> > * @f: resulting fence object
> > + * @job: job the fence is embeded in
> > * @flags: flags to pass into the subordinate .emit_fence() call
> > *
> > * Emits a fence command on the requested ring (all asics).
> > * Returns 0 on success, -ENOMEM on failure.
> > */
> > -int amdgpu_fence_emit(struct amdgpu_ring *ring, struct dma_fence **f,
> > +int amdgpu_fence_emit(struct amdgpu_ring *ring, struct dma_fence **f, struct amdgpu_job *job,
> > unsigned flags)
> > {
> > struct amdgpu_device *adev = ring->adev;
> > - struct amdgpu_fence *fence;
> > + struct dma_fence *fence;
> > + struct amdgpu_fence *am_fence;
> > struct dma_fence __rcu **ptr;
> > uint32_t seq;
> > int r;
> > - fence = kmem_cache_alloc(amdgpu_fence_slab, GFP_KERNEL);
> > - if (fence == NULL)
> > - return -ENOMEM;
> > + if (job == NULL) {
> > + /* create a sperate hw fence */
> > + am_fence = kmem_cache_alloc(amdgpu_fence_slab, GFP_ATOMIC);
> > + if (am_fence == NULL)
> > + return -ENOMEM;
> > + fence = &am_fence->base;
> > + am_fence->ring = ring;
> > + } else {
> > + /* take use of job-embedded fence */
> > + fence = &job->hw_fence;
> > + job->ring = ring;
>
>
> If you would make hw_fence of type amdgpu_fence
> you could probably avoid the special job->ring = ring
> See more in related comment at the bottom
>
Hi Andry,
I'm only make the amdgpu_fence for the fence without job parameter
provided to amdgpu_fence_emit. For embeded fence which is the hw_fence
in amdgpu_job, it will be allocated along with amdgpu_job as dma_fence.
Regards,
Jingwen Chen
>
> > + }
> > seq = ++ring->fence_drv.sync_seq;
> > - fence->ring = ring;
> > - dma_fence_init(&fence->base, &amdgpu_fence_ops,
> > + dma_fence_init(fence, &amdgpu_fence_ops,
> > &ring->fence_drv.lock,
> > adev->fence_context + ring->idx,
> > seq);
> > +
> > + if (job != NULL) {
> > + /* mark this fence has a parent job */
> > + set_bit(AMDGPU_FENCE_FLAG_EMBED_IN_JOB_BIT, &fence->flags);
> > + }
> > +
> > amdgpu_ring_emit_fence(ring, ring->fence_drv.gpu_addr,
> > seq, flags | AMDGPU_FENCE_FLAG_INT);
> > pm_runtime_get_noresume(adev_to_drm(adev)->dev);
> > @@ -175,9 +191,9 @@ int amdgpu_fence_emit(struct amdgpu_ring *ring, struct dma_fence **f,
> > /* This function can't be called concurrently anyway, otherwise
> > * emitting the fence would mess up the hardware ring buffer.
> > */
> > - rcu_assign_pointer(*ptr, dma_fence_get(&fence->base));
> > + rcu_assign_pointer(*ptr, dma_fence_get(fence));
> > - *f = &fence->base;
> > + *f = fence;
> > return 0;
> > }
> > @@ -621,8 +637,16 @@ static const char *amdgpu_fence_get_driver_name(struct dma_fence *fence)
> > static const char *amdgpu_fence_get_timeline_name(struct dma_fence *f)
> > {
> > - struct amdgpu_fence *fence = to_amdgpu_fence(f);
> > - return (const char *)fence->ring->name;
> > + struct amdgpu_ring *ring;
> > +
> > + if (test_bit(AMDGPU_FENCE_FLAG_EMBED_IN_JOB_BIT, &f->flags)) {
> > + struct amdgpu_job *job = container_of(f, struct amdgpu_job, hw_fence);
> > +
> > + ring = job->ring;
> > + } else {
> > + ring = to_amdgpu_fence(f)->ring;
> > + }
>
>
> Same as above
>
>
> > + return (const char *)ring->name;
> > }
> > /**
> > @@ -656,8 +680,20 @@ static bool amdgpu_fence_enable_signaling(struct dma_fence *f)
> > static void amdgpu_fence_free(struct rcu_head *rcu)
> > {
> > struct dma_fence *f = container_of(rcu, struct dma_fence, rcu);
> > - struct amdgpu_fence *fence = to_amdgpu_fence(f);
> > - kmem_cache_free(amdgpu_fence_slab, fence);
> > +
> > + if (test_bit(AMDGPU_FENCE_FLAG_EMBED_IN_JOB_BIT, &f->flags)) {
> > + /* free job if fence has a parent job */
> > + struct amdgpu_job *job;
> > +
> > + job = container_of(f, struct amdgpu_job, hw_fence);
> > + kfree(job);
> > + } else {
> > + /* free fence_slab if it's separated fence*/
> > + struct amdgpu_fence *fence;
> > +
> > + fence = to_amdgpu_fence(f);
> > + kmem_cache_free(amdgpu_fence_slab, fence);
> > + }
> > }
> > /**
> > @@ -680,6 +716,7 @@ static const struct dma_fence_ops amdgpu_fence_ops = {
> > .release = amdgpu_fence_release,
> > };
> > +
> > /*
> > * Fence debugfs
> > */
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
> > index ec65ab0ddf89..c076a6b9a5a2 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
> > @@ -262,7 +262,7 @@ int amdgpu_ib_schedule(struct amdgpu_ring *ring, unsigned num_ibs,
> > fence_flags | AMDGPU_FENCE_FLAG_64BIT);
> > }
> > - r = amdgpu_fence_emit(ring, f, fence_flags);
> > + r = amdgpu_fence_emit(ring, f, job, fence_flags);
> > if (r) {
> > dev_err(adev->dev, "failed to emit fence (%d)\n", r);
> > if (job && job->vmid)
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
> > index d33e6d97cc89..65a395060de2 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
> > @@ -127,11 +127,16 @@ void amdgpu_job_free_resources(struct amdgpu_job *job)
> > {
> > struct amdgpu_ring *ring = to_amdgpu_ring(job->base.sched);
> > struct dma_fence *f;
> > + struct dma_fence *hw_fence;
> > unsigned i;
> > - /* use sched fence if available */
> > - f = job->base.s_fence ? &job->base.s_fence->finished : job->fence;
> > + if (job->hw_fence.ops == NULL)
> > + hw_fence = job->external_hw_fence;
> > + else
> > + hw_fence = &job->hw_fence;
> > + /* use sched fence if available */
> > + f = job->base.s_fence ? &job->base.s_fence->finished : hw_fence;
> > for (i = 0; i < job->num_ibs; ++i)
> > amdgpu_ib_free(ring->adev, &job->ibs[i], f);
> > }
> > @@ -142,20 +147,27 @@ static void amdgpu_job_free_cb(struct drm_sched_job *s_job)
> > drm_sched_job_cleanup(s_job);
> > - dma_fence_put(job->fence);
> > amdgpu_sync_free(&job->sync);
> > amdgpu_sync_free(&job->sched_sync);
> > - kfree(job);
> > +
> > + /* only put the hw fence if has embedded fence */
> > + if (job->hw_fence.ops != NULL)
> > + dma_fence_put(&job->hw_fence);
> > + else
> > + kfree(job);
> > }
> > void amdgpu_job_free(struct amdgpu_job *job)
> > {
> > amdgpu_job_free_resources(job);
> > -
> > - dma_fence_put(job->fence);
> > amdgpu_sync_free(&job->sync);
> > amdgpu_sync_free(&job->sched_sync);
> > - kfree(job);
> > +
> > + /* only put the hw fence if has embedded fence */
> > + if (job->hw_fence.ops != NULL)
> > + dma_fence_put(&job->hw_fence);
> > + else
> > + kfree(job);
> > }
> > int amdgpu_job_submit(struct amdgpu_job *job, struct drm_sched_entity *entity,
> > @@ -184,11 +196,14 @@ int amdgpu_job_submit_direct(struct amdgpu_job *job, struct amdgpu_ring *ring,
> > job->base.sched = &ring->sched;
> > r = amdgpu_ib_schedule(ring, job->num_ibs, job->ibs, NULL, fence);
> > - job->fence = dma_fence_get(*fence);
> > + /* record external_hw_fence for direct submit */
> > + job->external_hw_fence = dma_fence_get(*fence);
> > if (r)
> > return r;
> > amdgpu_job_free(job);
> > + dma_fence_put(*fence);
> > +
> > return 0;
> > }
> > @@ -246,10 +261,8 @@ static struct dma_fence *amdgpu_job_run(struct drm_sched_job *sched_job)
> > if (r)
> > DRM_ERROR("Error scheduling IBs (%d)\n", r);
> > }
> > - /* if gpu reset, hw fence will be replaced here */
> > - dma_fence_put(job->fence);
> > - job->fence = dma_fence_get(fence);
> > + dma_fence_get(fence);
> > amdgpu_job_free_resources(job);
> > fence = r ? ERR_PTR(r) : fence;
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h
> > index 81caac9b958a..92324c978534 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h
> > @@ -46,7 +46,9 @@ struct amdgpu_job {
> > struct amdgpu_sync sync;
> > struct amdgpu_sync sched_sync;
> > struct amdgpu_ib *ibs;
> > - struct dma_fence *fence; /* the hw fence */
> > + struct dma_fence hw_fence;
> > + struct amdgpu_ring *ring;
>
> Why not instead of 2 fields above just embed struct amdgpu_fence as
> hw_fence and by this save the extra 'ring' field handling ?
>
> Andrey
>
>
> > + struct dma_fence *external_hw_fence;
> > uint32_t preamble_status;
> > uint32_t preemption_status;
> > uint32_t num_ibs;
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
> > index 9c11ced4312c..03d4b29a76d6 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
> > @@ -48,6 +48,9 @@
> > #define AMDGPU_FENCE_FLAG_INT (1 << 1)
> > #define AMDGPU_FENCE_FLAG_TC_WB_ONLY (1 << 2)
> > +/* fence flag bit to indicate the face is embeded in job*/
> > +#define AMDGPU_FENCE_FLAG_EMBED_IN_JOB_BIT (DMA_FENCE_FLAG_USER_BITS + 1)
> > +
> > #define to_amdgpu_ring(s) container_of((s), struct amdgpu_ring, sched)
> > #define AMDGPU_IB_POOL_SIZE (1024 * 1024)
> > @@ -118,7 +121,7 @@ void amdgpu_fence_driver_hw_init(struct amdgpu_device *adev);
> > void amdgpu_fence_driver_hw_fini(struct amdgpu_device *adev);
> > int amdgpu_fence_driver_sw_init(struct amdgpu_device *adev);
> > void amdgpu_fence_driver_sw_fini(struct amdgpu_device *adev);
> > -int amdgpu_fence_emit(struct amdgpu_ring *ring, struct dma_fence **fence,
> > +int amdgpu_fence_emit(struct amdgpu_ring *ring, struct dma_fence **fence, struct amdgpu_job *job,
> > unsigned flags);
> > int amdgpu_fence_emit_polling(struct amdgpu_ring *ring, uint32_t *s,
> > uint32_t timeout);
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> > index 2a88ed5d983b..2af8860d74cc 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> > @@ -1218,7 +1218,7 @@ int amdgpu_vm_flush(struct amdgpu_ring *ring, struct amdgpu_job *job,
> > amdgpu_gmc_emit_pasid_mapping(ring, job->vmid, job->pasid);
> > if (vm_flush_needed || pasid_mapping_needed) {
> > - r = amdgpu_fence_emit(ring, &fence, 0);
> > + r = amdgpu_fence_emit(ring, &fence, NULL, 0);
> > if (r)
> > return r;
> > }
