When we run out of VMIDs we need to wait for some to become available. Previously we were using a dma_fence_array for that, but this means that we have to allocate memory.
Instead just wait for the first not signaled fence from the least recently used VMID to signal. That is not as efficient since we end up in this function multiple times again, but allocating memory can easily fail or deadlock if we have to wait for memory to become available. Signed-off-by: Christian König <[email protected]> --- drivers/gpu/drm/amd/amdgpu/amdgpu_ids.c | 51 ++++++------------------- 1 file changed, 12 insertions(+), 39 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ids.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ids.c index 3ef5bc95642c..5f94a66511af 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ids.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ids.c @@ -201,58 +201,31 @@ static int amdgpu_vmid_grab_idle(struct amdgpu_ring *ring, struct amdgpu_device *adev = ring->adev; unsigned vmhub = ring->vm_hub; struct amdgpu_vmid_mgr *id_mgr = &adev->vm_manager.id_mgr[vmhub]; - struct dma_fence **fences; - unsigned i; + /* If anybody is waiting for a VMID let everybody wait for fairness */ if (!dma_fence_is_signaled(ring->vmid_wait)) { *fence = dma_fence_get(ring->vmid_wait); return 0; } - fences = kmalloc_array(id_mgr->num_ids, sizeof(void *), GFP_NOWAIT); - if (!fences) - return -ENOMEM; - /* Check if we have an idle VMID */ - i = 0; - list_for_each_entry((*idle), &id_mgr->ids_lru, list) { + list_for_each_entry_reverse((*idle), &id_mgr->ids_lru, list) { /* Don't use per engine and per process VMID at the same time */ struct amdgpu_ring *r = adev->vm_manager.concurrent_flush ? NULL : ring; - fences[i] = amdgpu_sync_peek_fence(&(*idle)->active, r); - if (!fences[i]) - break; - ++i; - } - - /* If we can't find a idle VMID to use, wait till one becomes available */ - if (&(*idle)->list == &id_mgr->ids_lru) { - u64 fence_context = adev->vm_manager.fence_context + ring->idx; - unsigned seqno = ++adev->vm_manager.seqno[ring->idx]; - struct dma_fence_array *array; - unsigned j; - - *idle = NULL; - for (j = 0; j < i; ++j) - dma_fence_get(fences[j]); - - array = dma_fence_array_create(i, fences, fence_context, - seqno, true); - if (!array) { - for (j = 0; j < i; ++j) - dma_fence_put(fences[j]); - kfree(fences); - return -ENOMEM; - } - - *fence = dma_fence_get(&array->base); - dma_fence_put(ring->vmid_wait); - ring->vmid_wait = &array->base; - return 0; + *fence = amdgpu_sync_peek_fence(&(*idle)->active, r); + if (!(*fence)) + return 0; } - kfree(fences); + /* + * If we can't find a idle VMID to use, wait on a fence from the least + * recently used in the hope that it will be available soon. + */ + *idle = NULL; + dma_fence_put(ring->vmid_wait); + ring->vmid_wait = dma_fence_get(*fence); return 0; } -- 2.43.0
