Re: [PATCH 11/12] drm/ttm: support using drm_exec during eviction v4

["Thomas Hellström" <thomas.hellstrom@linux.intel.com>]

On Fri, 2026-07-10 at 20:52 +0200, Christian König wrote:
> Allow specifying a drm_exec object in TTMs operation context which is
> used to lock objects during eviction.
> 
> This allows to handle deadlocks much more gracefully and with that
> avoid returning -ENOMEM on heavily contended domains.
> 
> v2: rebased on top of Thomas work
> v3: rebased again
> v4: adjust to dma_resv changes
> 
> Signed-off-by: Christian König <christian.koenig@amd.com>

Same thing here. Use a ww context at the dma-buf level.

Thanks,
Thomas


> ---
>  drivers/gpu/drm/ttm/ttm_bo_util.c | 12 ++++++++----
>  include/drm/ttm/ttm_bo.h          |  5 +++++
>  2 files changed, 13 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c
> b/drivers/gpu/drm/ttm/ttm_bo_util.c
> index 1bdd69643c313..570640ae79d84 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo_util.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
> @@ -38,6 +38,7 @@
>  #include <drm/ttm/ttm_tt.h>
>  
>  #include <drm/drm_cache.h>
> +#include <drm/drm_exec.h>
>  
>  struct ttm_transfer_obj {
>  	struct ttm_buffer_object base;
> @@ -839,7 +840,9 @@ static int ttm_lru_walk_ticketlock(struct
> ttm_bo_lru_cursor *curs,
>  	struct ttm_lru_walk_arg *arg = curs->arg;
>  	int ret;
>  
> -	if (arg->ctx->interruptible)
> +	if (arg->ctx->exec)
> +		ret = drm_exec_lock_resv(arg->ctx->exec, resv);
> +	else if (arg->ctx->interruptible)
>  		ret = dma_resv_lock_interruptible(resv, arg-
> >ticket);
>  	else
>  		ret = dma_resv_lock(resv, arg->ticket);
> @@ -853,7 +856,8 @@ static int ttm_lru_walk_ticketlock(struct
> ttm_bo_lru_cursor *curs,
>  		 * trylocking for this walk.
>  		 */
>  		arg->ticket = NULL;
> -	} else if (ret == -EDEADLK) {
> +
> +	} else if (!arg->ctx->exec && ret == -EDEADLK) {
>  		/* Caller needs to exit the ww transaction. */
>  		ret = -ENOSPC;
>  	}
> @@ -993,8 +997,8 @@ __ttm_bo_lru_cursor_iter(struct ttm_bo_lru_cursor
> *curs, bool first)
>  		if (!ttm_lru_walk_trylock(curs, res->bo->base.resv))
> {
>  			struct dma_resv *resv;
>  
> -			if (!arg->ticket || arg->ctx->no_wait_gpu ||
> -			    arg->trylock_only) {
> +			if ((!arg->ticket || arg->ctx->no_wait_gpu
> ||
> +			     arg->trylock_only) && !arg->ctx->exec)
> {
>  				spin_unlock(lru_lock);
>  				continue;
>  			}
> diff --git a/include/drm/ttm/ttm_bo.h b/include/drm/ttm/ttm_bo.h
> index e1221e3be7bda..0ffa84a5caa65 100644
> --- a/include/drm/ttm/ttm_bo.h
> +++ b/include/drm/ttm/ttm_bo.h
> @@ -186,6 +186,11 @@ struct ttm_operation_ctx {
>  	 * @bytes_moved: Statistics on how many bytes have been
> moved.
>  	 */
>  	uint64_t bytes_moved;
> +	/*
> +	 * @exec: optional drm_exec object to use for locking and
> contention
> +	 * handling
> +	 */
> +	struct drm_exec *exec;
>  };
>  
>  struct ttm_lru_walk;