[PATCH 3/3] drm/amdgpu: improve VM state machine documentation

Christian König
2018-09-01T18:05:09Z

Since we have a lot of FAQ on the VM state machine try to improve the
documentation by adding functions for each state move.

Signed-off-by: Christian König <christian.koenig@amd.com>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 139 +++++++++++++++++++++++++--------
1 file changed, 108 insertions(+), 31 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 65977e7c94dc..ce252ead2ee4 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -204,6 +204,95 @@ static unsigned amdgpu_vm_bo_size(struct amdgpu_device *adev, unsigned level)
return AMDGPU_GPU_PAGE_ALIGN(amdgpu_vm_num_entries(adev, level) * 8);
}

+/**
+ * amdgpu_vm_bo_evicted - vm_bo is evicted
+ *
+ * @vm_bo: vm_bo which is evicted
+ *
+ * State for PDs/PTs and per VM BOs which are not at the location they should
+ * be.
+ */
+static void amdgpu_vm_bo_evicted(struct amdgpu_vm_bo_base *vm_bo)
+{
+ struct amdgpu_vm *vm = vm_bo->vm;
+ struct amdgpu_bo *bo = vm_bo->bo;
+
+ vm_bo->moved = true;
+ if (bo->tbo.type == ttm_bo_type_kernel)
+ list_move(&vm_bo->vm_status, &vm->evicted);
+ else
+ list_move_tail(&vm_bo->vm_status, &vm->evicted);
+}
+
+/**
+ * amdgpu_vm_bo_relocated - vm_bo is reloacted
+ *
+ * @vm_bo: vm_bo which is relocated
+ *
+ * State for PDs/PTs which needs to update their parent PD.
+ */
+static void amdgpu_vm_bo_relocated(struct amdgpu_vm_bo_base *vm_bo)
+{
+ list_move(&vm_bo->vm_status, &vm_bo->vm->relocated);
+}
+
+/**
+ * amdgpu_vm_bo_moved - vm_bo is moved
+ *
+ * @vm_bo: vm_bo which is moved
+ *
+ * State for per VM BOs which are moved, but that change is not yet reflected
+ * in the page tables.
+ */
+static void amdgpu_vm_bo_moved(struct amdgpu_vm_bo_base *vm_bo)
+{
+ list_move(&vm_bo->vm_status, &vm_bo->vm->moved);
+}
+
+/**
+ * amdgpu_vm_bo_idle - vm_bo is idle
+ *
+ * @vm_bo: vm_bo which is now idle
+ *
+ * State for PDs/PTs and per VM BOs which have gone through the state machine
+ * and are now idle.
+ */
+static void amdgpu_vm_bo_idle(struct amdgpu_vm_bo_base *vm_bo)
+{
+ list_move(&vm_bo->vm_status, &vm_bo->vm->idle);
+ vm_bo->moved = false;
+}
+
+/**
+ * amdgpu_vm_bo_invalidated - vm_bo is invalidated
+ *
+ * @vm_bo: vm_bo which is now invalidated
+ *
+ * State for normal BOs which are invalidated and that change not yet reflected
+ * in the PTs.
+ */
+static void amdgpu_vm_bo_invalidated(struct amdgpu_vm_bo_base *vm_bo)
+{
+ spin_lock(&vm_bo->vm->invalidated_lock);
+ list_move(&vm_bo->vm_status, &vm_bo->vm->idle);
+ spin_unlock(&vm_bo->vm->invalidated_lock);
+}
+
+/**
+ * amdgpu_vm_bo_done - vm_bo is done
+ *
+ * @vm_bo: vm_bo which is now done
+ *
+ * State for normal BOs which are invalidated and that change has been updated
+ * in the PTs.
+ */
+static void amdgpu_vm_bo_done(struct amdgpu_vm_bo_base *vm_bo)
+{
+ spin_lock(&vm_bo->vm->invalidated_lock);
+ list_del_init(&vm_bo->vm_status);
+ spin_unlock(&vm_bo->vm->invalidated_lock);
+}
+
/**
* amdgpu_vm_bo_base_init - Adds bo to the list of bos associated with the vm
*
@@ -232,9 +321,9 @@ static void amdgpu_vm_bo_base_init(struct amdgpu_vm_bo_base *base,

vm->bulk_moveable = false;
if (bo->tbo.type == ttm_bo_type_kernel)
- list_move(&base->vm_status, &vm->relocated);
+ amdgpu_vm_bo_relocated(base);
else
- list_move(&base->vm_status, &vm->idle);
+ amdgpu_vm_bo_idle(base);

if (bo->preferred_domains &
amdgpu_mem_type_to_domain(bo->tbo.mem.mem_type))
@@ -245,8 +334,7 @@ static void amdgpu_vm_bo_base_init(struct amdgpu_vm_bo_base *base,
* is currently evicted. add the bo to the evicted list to make sure it
* is validated on next vm use to avoid fault.
* */
- list_move_tail(&base->vm_status, &vm->evicted);
- base->moved = true;
+ amdgpu_vm_bo_evicted(base);
}

/**
@@ -342,7 +430,7 @@ int amdgpu_vm_validate_pt_bos(struct amdgpu_device *adev, struct amdgpu_vm *vm,
break;

if (bo->tbo.type != ttm_bo_type_kernel) {
- list_move(&bo_base->vm_status, &vm->moved);
+ amdgpu_vm_bo_moved(bo_base);
} else {
if (vm->use_cpu_for_update)
r = amdgpu_bo_kmap(bo, NULL);
@@ -350,7 +438,7 @@ int amdgpu_vm_validate_pt_bos(struct amdgpu_device *adev, struct amdgpu_vm *vm,
r = amdgpu_ttm_alloc_gart(&bo->tbo);
if (r)
break;
- list_move(&bo_base->vm_status, &vm->relocated);
+ amdgpu_vm_bo_relocated(bo_base);
}
}

@@ -1121,8 +1209,7 @@ int amdgpu_vm_update_directories(struct amdgpu_device *adev,
bo_base = list_first_entry(&vm->relocated,
struct amdgpu_vm_bo_base,
vm_status);
- bo_base->moved = false;
- list_move(&bo_base->vm_status, &vm->idle);
+ amdgpu_vm_bo_idle(bo_base);

bo = bo_base->bo->parent;
if (!bo)
@@ -1241,7 +1328,7 @@ static void amdgpu_vm_handle_huge_pages(struct amdgpu_pte_update_params *p,
if (entry->huge) {
/* Add the entry to the relocated list to update it. */
entry->huge = false;
- list_move(&entry->base.vm_status, &p->vm->relocated);
+ amdgpu_vm_bo_relocated(&entry->base);
}
return;
}
@@ -1740,13 +1827,11 @@ int amdgpu_vm_bo_update(struct amdgpu_device *adev,
uint32_t mem_type = bo->tbo.mem.mem_type;

if (!(bo->preferred_domains & amdgpu_mem_type_to_domain(mem_type)))
- list_move_tail(&bo_va->base.vm_status, &vm->evicted);
+ amdgpu_vm_bo_evicted(&bo_va->base);
else
- list_move(&bo_va->base.vm_status, &vm->idle);
+ amdgpu_vm_bo_idle(&bo_va->base);
} else {
- spin_lock(&vm->invalidated_lock);
- list_del_init(&bo_va->base.vm_status);
- spin_unlock(&vm->invalidated_lock);
+ amdgpu_vm_bo_done(&bo_va->base);
}

list_splice_init(&bo_va->invalids, &bo_va->valids);
@@ -2468,30 +2553,22 @@ void amdgpu_vm_bo_invalidate(struct amdgpu_device *adev,

list_for_each_entry(bo_base, &bo->va, bo_list) {
struct amdgpu_vm *vm = bo_base->vm;
- bool was_moved = bo_base->moved;

- bo_base->moved = true;
if (evicted && bo->tbo.resv == vm->root.base.bo->tbo.resv) {
- if (bo->tbo.type == ttm_bo_type_kernel)
- list_move(&bo_base->vm_status, &vm->evicted);
- else
- list_move_tail(&bo_base->vm_status,
- &vm->evicted);
+ amdgpu_vm_bo_evicted(bo_base);
continue;
}

- if (was_moved)
+ if (bo_base->moved)
continue;
+ bo_base->moved = true;

- if (bo->tbo.type == ttm_bo_type_kernel) {
- list_move(&bo_base->vm_status, &vm->relocated);
- } else if (bo->tbo.resv == vm->root.base.bo->tbo.resv) {
- list_move(&bo_base->vm_status, &vm->moved);
- } else {
- spin_lock(&vm->invalidated_lock);
- list_move(&bo_base->vm_status, &vm->invalidated);
- spin_unlock(&vm->invalidated_lock);
- }
+ if (bo->tbo.type == ttm_bo_type_kernel)
+ amdgpu_vm_bo_relocated(bo_base);
+ else if (bo->tbo.resv == vm->root.base.bo->tbo.resv)
+ amdgpu_vm_bo_moved(bo_base);
+ else
+ amdgpu_vm_bo_invalidated(bo_base);