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Commit 8d76001e authored by Christian König's avatar Christian König Committed by Alex Deucher
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drm/amdgpu: reuse VMIDs assigned to a VM only if there is also a free one 



This fixes a fairness problem with the GPU scheduler. VM having lot of
jobs could previously starve VM with less jobs.

Acked-by: default avatarAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: default avatarChristian König <christian.koenig@amd.com>
Acked-by: default avatarChunming Zhou <david1.zhou@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 36fd7c5c

drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c

+59 −54
Original line number Diff line number Diff line
@@ -179,12 +179,25 @@ int amdgpu_vm_grab_id(struct amdgpu_vm *vm, struct amdgpu_ring *ring, 
	uint64_t pd_addr = amdgpu_bo_gpu_offset(vm->page_directory);

	struct amdgpu_device *adev = ring->adev;

	struct fence *updates = sync->last_vm_update;

	struct amdgpu_vm_id *id;

	struct amdgpu_vm_id *id, *idle;

	unsigned i = ring->idx;

	int r;



	mutex_lock(&adev->vm_manager.lock);



	/* Check if we have an idle VMID */

	list_for_each_entry(idle, &adev->vm_manager.ids_lru, list) {

		if (amdgpu_sync_is_idle(&idle->active, ring))

			break;



	}



	/* If we can't find a idle VMID to use, just wait for the oldest */

	if (&idle->list == &adev->vm_manager.ids_lru) {

		id = list_first_entry(&adev->vm_manager.ids_lru,

				      struct amdgpu_vm_id,

				      list);

	} else {

		/* Check if we can use a VMID already assigned to this VM */

		do {

			struct fence *flushed;
@@ -203,12 +216,13 @@ int amdgpu_vm_grab_id(struct amdgpu_vm *vm, struct amdgpu_ring *ring, 
			if (pd_addr != id->pd_gpu_addr)

				continue;



		if (id->last_user != ring &&

		    (!id->last_flush || !fence_is_signaled(id->last_flush)))

			if (id->last_user != ring && (!id->last_flush ||

			    !fence_is_signaled(id->last_flush)))

				continue;



			flushed  = id->flushed_updates;

		if (updates && (!flushed || fence_is_later(updates, flushed)))

			if (updates && (!flushed ||

			    fence_is_later(updates, flushed)))

				continue;



			/* Good we can use this VMID */
@@ -229,25 +243,16 @@ int amdgpu_vm_grab_id(struct amdgpu_vm *vm, struct amdgpu_ring *ring, 


			*vm_id = id - adev->vm_manager.ids;

			*vm_pd_addr = AMDGPU_VM_NO_FLUSH;

		trace_amdgpu_vm_grab_id(vm, ring->idx, *vm_id, *vm_pd_addr);

			trace_amdgpu_vm_grab_id(vm, ring->idx, *vm_id,

						*vm_pd_addr);



			mutex_unlock(&adev->vm_manager.lock);

			return 0;



		} while (i != ring->idx);



	/* Check if we have an idle VMID */

	list_for_each_entry(id, &adev->vm_manager.ids_lru, list) {

		if (amdgpu_sync_is_idle(&id->active, ring))

			break;



	}



	/* If we can't find a idle VMID to use, just wait for the oldest */

	if (&id->list == &adev->vm_manager.ids_lru) {

		id = list_first_entry(&adev->vm_manager.ids_lru,

				      struct amdgpu_vm_id,

				      list);

		/* Still no ID to use? Then use the idle one found earlier */

		id = idle;

	}



	r = amdgpu_sync_cycle_fences(sync, &id->active, fence);