[PATCH 10/12] drm/amdgpu: add gang submit backend v2
Christian König
ckoenig.leichtzumerken at gmail.com
Mon Sep 5 12:32:30 UTC 2022
Allows submitting jobs as gang which needs to run on multiple
engines at the same time.
Basic idea is that we have a global gang submit fence representing when the
gang leader is finally pushed to run on the hardware last.
Jobs submitted as gang are never re-submitted in case of a GPU reset since this
won't work and will just deadlock the hardware immediately again.
v2: fix logic inversion, improve documentation, fix rcu
Signed-off-by: Christian König <christian.koenig at amd.com>
---
drivers/gpu/drm/amd/amdgpu/amdgpu.h | 3 ++
drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 35 ++++++++++++++++++++++
drivers/gpu/drm/amd/amdgpu/amdgpu_job.c | 28 +++++++++++++++--
drivers/gpu/drm/amd/amdgpu/amdgpu_job.h | 3 ++
4 files changed, 67 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 79bb6fd83094..ae9371b172e3 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -885,6 +885,7 @@ struct amdgpu_device {
u64 fence_context;
unsigned num_rings;
struct amdgpu_ring *rings[AMDGPU_MAX_RINGS];
+ struct dma_fence __rcu *gang_submit;
bool ib_pool_ready;
struct amdgpu_sa_manager ib_pools[AMDGPU_IB_POOL_MAX];
struct amdgpu_sched gpu_sched[AMDGPU_HW_IP_NUM][AMDGPU_RING_PRIO_MAX];
@@ -1294,6 +1295,8 @@ u32 amdgpu_device_pcie_port_rreg(struct amdgpu_device *adev,
u32 reg);
void amdgpu_device_pcie_port_wreg(struct amdgpu_device *adev,
u32 reg, u32 v);
+struct dma_fence *amdgpu_device_switch_gang(struct amdgpu_device *adev,
+ struct dma_fence *gang);
/* atpx handler */
#if defined(CONFIG_VGA_SWITCHEROO)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index d7eb23b8d692..172095122cc1 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -3501,6 +3501,7 @@ int amdgpu_device_init(struct amdgpu_device *adev,
adev->gmc.gart_size = 512 * 1024 * 1024;
adev->accel_working = false;
adev->num_rings = 0;
+ RCU_INIT_POINTER(adev->gang_submit, dma_fence_get_stub());
adev->mman.buffer_funcs = NULL;
adev->mman.buffer_funcs_ring = NULL;
adev->vm_manager.vm_pte_funcs = NULL;
@@ -3983,6 +3984,7 @@ void amdgpu_device_fini_sw(struct amdgpu_device *adev)
release_firmware(adev->firmware.gpu_info_fw);
adev->firmware.gpu_info_fw = NULL;
adev->accel_working = false;
+ dma_fence_put(rcu_dereference_protected(adev->gang_submit, true));
amdgpu_reset_fini(adev);
@@ -5916,3 +5918,36 @@ void amdgpu_device_pcie_port_wreg(struct amdgpu_device *adev,
(void)RREG32(data);
spin_unlock_irqrestore(&adev->pcie_idx_lock, flags);
}
+
+/**
+ * amdgpu_device_switch_gang - switch to a new gang
+ * @adev: amdgpu_device pointer
+ * @gang: the gang to switch to
+ *
+ * Try to switch to a new gang.
+ * Returns: NULL if we switched to the new gang or a reference to the current
+ * gang leader.
+ */
+struct dma_fence *amdgpu_device_switch_gang(struct amdgpu_device *adev,
+ struct dma_fence *gang)
+{
+ struct dma_fence *old = NULL;
+
+ do {
+ dma_fence_put(old);
+ rcu_read_lock();
+ old = dma_fence_get_rcu_safe(&adev->gang_submit);
+ rcu_read_unlock();
+
+ if (old == gang)
+ break;
+
+ if (!dma_fence_is_signaled(old))
+ return old;
+
+ } while (cmpxchg((struct dma_fence __force **)&adev->gang_submit,
+ old, gang) != old);
+
+ dma_fence_put(old);
+ return NULL;
+}
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
index 37dc5ee4153d..6f6708caf0e6 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
@@ -173,11 +173,29 @@ static void amdgpu_job_free_cb(struct drm_sched_job *s_job)
dma_fence_put(&job->hw_fence);
}
+void amdgpu_job_set_gang_leader(struct amdgpu_job *job,
+ struct amdgpu_job *leader)
+{
+ struct dma_fence *fence = &leader->base.s_fence->scheduled;
+
+ WARN_ON(job->gang_submit);
+
+ /*
+ * Don't add a reference when we are the gang leader to avoid circle
+ * dependency.
+ */
+ if (job != leader)
+ dma_fence_get(fence);
+ job->gang_submit = fence;
+}
+
void amdgpu_job_free(struct amdgpu_job *job)
{
amdgpu_job_free_resources(job);
amdgpu_sync_free(&job->sync);
amdgpu_sync_free(&job->sched_sync);
+ if (job->gang_submit != &job->base.s_fence->scheduled)
+ dma_fence_put(job->gang_submit);
dma_fence_put(&job->hw_fence);
}
@@ -244,12 +262,16 @@ static struct dma_fence *amdgpu_job_dependency(struct drm_sched_job *sched_job,
fence = amdgpu_sync_get_fence(&job->sync);
}
+ if (!fence && job->gang_submit)
+ fence = amdgpu_device_switch_gang(ring->adev, job->gang_submit);
+
return fence;
}
static struct dma_fence *amdgpu_job_run(struct drm_sched_job *sched_job)
{
struct amdgpu_ring *ring = to_amdgpu_ring(sched_job->sched);
+ struct amdgpu_device *adev = ring->adev;
struct dma_fence *fence = NULL, *finished;
struct amdgpu_job *job;
int r = 0;
@@ -261,8 +283,10 @@ static struct dma_fence *amdgpu_job_run(struct drm_sched_job *sched_job)
trace_amdgpu_sched_run_job(job);
- if (job->vram_lost_counter != atomic_read(&ring->adev->vram_lost_counter))
- dma_fence_set_error(finished, -ECANCELED);/* skip IB as well if VRAM lost */
+ /* Skip job if VRAM is lost and never resubmit gangs */
+ if (job->vram_lost_counter != atomic_read(&adev->vram_lost_counter) ||
+ (job->job_run_counter && job->gang_submit))
+ dma_fence_set_error(finished, -ECANCELED);
if (finished->error < 0) {
DRM_INFO("Skip scheduling IBs!\n");
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h
index 866d35bbe073..ab7b150e5d50 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h
@@ -50,6 +50,7 @@ struct amdgpu_job {
struct amdgpu_sync sync;
struct amdgpu_sync sched_sync;
struct dma_fence hw_fence;
+ struct dma_fence *gang_submit;
uint32_t preamble_status;
uint32_t preemption_status;
bool vm_needs_flush;
@@ -84,6 +85,8 @@ int amdgpu_job_alloc_with_ib(struct amdgpu_device *adev, unsigned size,
void amdgpu_job_set_resources(struct amdgpu_job *job, struct amdgpu_bo *gds,
struct amdgpu_bo *gws, struct amdgpu_bo *oa);
void amdgpu_job_free_resources(struct amdgpu_job *job);
+void amdgpu_job_set_gang_leader(struct amdgpu_job *job,
+ struct amdgpu_job *leader);
void amdgpu_job_free(struct amdgpu_job *job);
int amdgpu_job_submit(struct amdgpu_job *job, struct drm_sched_entity *entity,
void *owner, struct dma_fence **f);
--
2.25.1
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