This update adds explanations to key functions that manage how the
Kernel Fusion Driver (KFD) and Kernel Graphics Driver (KGD) share the
GPU.
amdgpu_gfx_enforce_isolation_wait_for_kfd: Controls the waiting period
for KFD to ensure it takes turns with KGD in using the GPU. It uses a
mutex to safely manage shared data, like timing and state, and tracks
when KFD starts and stops waiting.
amdgpu_gfx_enforce_isolation_ring_begin_use: Ensures KFD has enough time
to run before new tasks are submitted to the GPU ring. It uses a mutex
to synchronize access and may adjust the KFD scheduler.
amdgpu_gfx_enforce_isolation_ring_end_use: Handles cleanup and state
updates when finishing the use of a GPU ring. It may also adjust the KFD
scheduler, using a mutex to manage shared data access.
Cc: Christian König <christian.koe...@amd.com>
Cc: Alex Deucher <alexander.deuc...@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmu...@amd.com>
Suggested-by: Alex Deucher <alexander.deuc...@amd.com>
---
v2:
- Incorporated feedbacks for function descriptions (Alex)
drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c | 29 +++++++++++++++++++++++++
1 file changed, 29 insertions(+)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c
index e54f42e3797e..b1b133affbf9 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c
@@ -1940,6 +1940,17 @@ void amdgpu_gfx_enforce_isolation_handler(struct
work_struct *work)
mutex_unlock(&adev->enforce_isolation_mutex);
}
+/**
+ * amdgpu_gfx_enforce_isolation_wait_for_kfd - Manage KFD wait period for
process isolation
+ * @adev: amdgpu_device pointer
+ * @idx: Index of the GPU partition
+ *
+ * When kernel submissions come in, the jobs are given a time slice and once
+ * that time slice is up, if there are KFD user queues active, kernel
+ * submissions are blocked until KFD has had its time slice. Once the KFD time
+ * slice is up, KFD user queues are preempted and kernel submissions are
+ * unblocked and allowed to run again.
+ */
static void
amdgpu_gfx_enforce_isolation_wait_for_kfd(struct amdgpu_device *adev,
u32 idx)
@@ -1985,6 +1996,15 @@ amdgpu_gfx_enforce_isolation_wait_for_kfd(struct
amdgpu_device *adev,
msleep(GFX_SLICE_PERIOD_MS);
}
+/**
+ * amdgpu_gfx_enforce_isolation_ring_begin_use - Begin use of a ring with
enforced isolation
+ * @ring: Pointer to the amdgpu_ring structure
+ *
+ * Ring begin_use helper implementation for gfx which serializes access to the
+ * gfx IP between kernel submission IOCTLs and KFD user queues when isolation
+ * enforcement is enabled. The kernel submission IOCTLs and KFD user queues
+ * each get a time slice when both are active.
+ */
void amdgpu_gfx_enforce_isolation_ring_begin_use(struct amdgpu_ring *ring)
{
struct amdgpu_device *adev = ring->adev;
@@ -2012,6 +2032,15 @@ void amdgpu_gfx_enforce_isolation_ring_begin_use(struct
amdgpu_ring *ring)
mutex_unlock(&adev->enforce_isolation_mutex);
}
+/**
+ * amdgpu_gfx_enforce_isolation_ring_end_use - End use of a ring with enforced
isolation
+ * @ring: Pointer to the amdgpu_ring structure
+ *
+ * Ring end_use helper implementation for gfx which serializes access to the
+ * gfx IP between kernel submission IOCTLs and KFD user queues when isolation
+ * enforcement is enabled. The kernel submission IOCTLs and KFD user queues
+ * each get a time slice when both are active.
+ */
void amdgpu_gfx_enforce_isolation_ring_end_use(struct amdgpu_ring *ring)
{
struct amdgpu_device *adev = ring->adev;
--
2.34.1
