[Intel-xe] [PATCH v2] drm/xe: Fix fence reservation accouting

[Thomas Hellström]

Hi,

On 9/11/23 23:18, Matthew Brost wrote:
> Both execs and the preempt rebind worker can issue rebinds. Rebinds
> require a fence, per tile, inserted into dma-resv slots of the VM and
> BO (if external). The fence reservation accouting did not take into
> account the number of fences required for rebinds, fix this.
>
> v2: Rebase
>
> Reported-by: Christopher Snowhill <kode54 at gmail.com>
> Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/518
> Signed-off-by: Matthew Brost <matthew.brost at intel.com>

Reviewed-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>


> ---
>   drivers/gpu/drm/xe/xe_exec.c | 6 +++++-
>   drivers/gpu/drm/xe/xe_vm.c   | 7 ++++++-
>   2 files changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/xe_exec.c b/drivers/gpu/drm/xe/xe_exec.c
> index 890fadb0a93e..eaf826f1b2a0 100644
> --- a/drivers/gpu/drm/xe/xe_exec.c
> +++ b/drivers/gpu/drm/xe/xe_exec.c
> @@ -103,7 +103,11 @@ static int xe_exec_begin(struct drm_exec *exec, struct xe_vm *vm)
>   	if (xe_vm_no_dma_fences(vm))
>   		return 0;
>   
> -	err = xe_vm_lock_dma_resv(vm, exec, 1, true);
> +	/*
> +	 * 1 fence for job from exec plus a fence for each tile from a possible
> +	 * rebind
> +	 */
> +	err = xe_vm_lock_dma_resv(vm, exec, 1 + vm->xe->info.tile_count, true);
>   	if (err)
>   		return err;
>   
> diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
> index a6a0f17fec1d..03ee6993e7c7 100644
> --- a/drivers/gpu/drm/xe/xe_vm.c
> +++ b/drivers/gpu/drm/xe/xe_vm.c
> @@ -515,8 +515,13 @@ static int xe_preempt_work_begin(struct drm_exec *exec, struct xe_vm *vm,
>   	struct xe_vma *vma;
>   	int err;
>   
> +	/*
> +	 * 1 fence for each preempt fence plus a fence for each tile from a
> +	 * possible rebind
> +	 */
>   	err = drm_exec_prepare_obj(exec, &xe_vm_ttm_bo(vm)->base,
> -				   vm->preempt.num_exec_queues);
> +				   vm->preempt.num_exec_queues +
> +				   vm->xe->info.tile_count);
>   	if (err)
>   		return err;
>