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 <[email protected]>
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;
