On Fri, 2025-02-07 at 14:50 +0000, Tvrtko Ursulin wrote:
> Idea is to add helpers for peeking and popping jobs from entities
> with
> the goal of decoupling the hidden assumption in the code that
> queue_node
> is the first element in struct drm_sched_job.
>
> That assumption usually comes in the form of:
>
> while ((job = to_drm_sched_job(spsc_queue_pop(&entity-
> >job_queue))))
>
> Which breaks if the queue_node is re-positioned due to_drm_sched_job
> being implemented with a container_of.
>
> This also allows us to remove duplicate definitions of
> to_drm_sched_job.
>
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxx>
> Cc: Christian König <christian.koenig@xxxxxxx>
> Cc: Danilo Krummrich <dakr@xxxxxxxxxx>
> Cc: Matthew Brost <matthew.brost@xxxxxxxxx>
> Cc: Philipp Stanner <phasta@xxxxxxxxxx>
> ---
> drivers/gpu/drm/scheduler/sched_entity.c | 11 +++---
> drivers/gpu/drm/scheduler/sched_internal.h | 46
> ++++++++++++++++++++++
> drivers/gpu/drm/scheduler/sched_main.c | 7 ++--
> 3 files changed, 54 insertions(+), 10 deletions(-)
> create mode 100644 drivers/gpu/drm/scheduler/sched_internal.h
>
> diff --git a/drivers/gpu/drm/scheduler/sched_entity.c
> b/drivers/gpu/drm/scheduler/sched_entity.c
> index 69bcf0e99d57..a171f05ad761 100644
> --- a/drivers/gpu/drm/scheduler/sched_entity.c
> +++ b/drivers/gpu/drm/scheduler/sched_entity.c
> @@ -28,11 +28,10 @@
> #include <drm/drm_print.h>
> #include <drm/gpu_scheduler.h>
>
> +#include "sched_internal.h"
> +
> #include "gpu_scheduler_trace.h"
>
> -#define to_drm_sched_job(sched_job) \
> - container_of((sched_job), struct drm_sched_job,
> queue_node)
> -
> /**
> * drm_sched_entity_init - Init a context entity used by scheduler
> when
> * submit to HW ring.
> @@ -255,7 +254,7 @@ static void drm_sched_entity_kill(struct
> drm_sched_entity *entity)
> /* The entity is guaranteed to not be used by the scheduler
> */
> prev = rcu_dereference_check(entity->last_scheduled, true);
> dma_fence_get(prev);
> - while ((job = to_drm_sched_job(spsc_queue_pop(&entity-
> >job_queue)))) {
> + while ((job = drm_sched_entity_queue_pop(entity))) {
> struct drm_sched_fence *s_fence = job->s_fence;
>
> dma_fence_get(&s_fence->finished);
> @@ -477,7 +476,7 @@ struct drm_sched_job
> *drm_sched_entity_pop_job(struct drm_sched_entity *entity)
> {
> struct drm_sched_job *sched_job;
>
> - sched_job = to_drm_sched_job(spsc_queue_peek(&entity-
> >job_queue));
> + sched_job = drm_sched_entity_queue_peek(entity);
> if (!sched_job)
> return NULL;
>
> @@ -513,7 +512,7 @@ struct drm_sched_job
> *drm_sched_entity_pop_job(struct drm_sched_entity *entity)
> if (drm_sched_policy == DRM_SCHED_POLICY_FIFO) {
> struct drm_sched_job *next;
>
> - next = to_drm_sched_job(spsc_queue_peek(&entity-
> >job_queue));
> + next = drm_sched_entity_queue_peek(entity);
> if (next) {
> struct drm_sched_rq *rq;
>
> diff --git a/drivers/gpu/drm/scheduler/sched_internal.h
> b/drivers/gpu/drm/scheduler/sched_internal.h
> new file mode 100644
> index 000000000000..25ac62ac2bf3
> --- /dev/null
> +++ b/drivers/gpu/drm/scheduler/sched_internal.h
> @@ -0,0 +1,46 @@
> +#ifndef _DRM_GPU_SCHEDULER_INTERNAL_H_
> +#define _DRM_GPU_SCHEDULER_INTERNAL_H_
> +
> +/**
> + * drm_sched_entity_queue_pop - Low level helper for popping queued
> jobs
> + *
> + * @entity: scheduler entity
> + *
> + * Low level helper for popping queued jobs.
> + *
> + * Returns the job dequeued or NULL.
> + */
> +static inline struct drm_sched_job *
> +drm_sched_entity_queue_pop(struct drm_sched_entity *entity)
> +{
> + struct spsc_node *node;
> +
> + node = spsc_queue_pop(&entity->job_queue);
> + if (!node)
> + return NULL;
> +
> + return container_of(node, struct drm_sched_job, queue_node);
> +}
> +
> +/**
> + * drm_sched_entity_queue_peek - Low level helper for peeking at the
> job queue
> + *
> + * @entity: scheduler entity
> + *
> + * Low level helper for peeking at the job queue
> + *
> + * Returns the job at the head of the queue or NULL.
I would like to (slowly) work towards a unified style regarding the
docstrings. They're currently relatively inconsistent in drm/sched.
I think we should do it that way:
""
@entity: scheduler entity
Returns: the job at the head of the queue or NULL.
Low level helper for peeking at the the job queue.
""
P.
> + */
> +static inline struct drm_sched_job *
> +drm_sched_entity_queue_peek(struct drm_sched_entity *entity)
> +{
> + struct spsc_node *node;
> +
> + node = spsc_queue_peek(&entity->job_queue);
> + if (!node)
> + return NULL;
> +
> + return container_of(node, struct drm_sched_job, queue_node);
> +}
> +
> +#endif
> diff --git a/drivers/gpu/drm/scheduler/sched_main.c
> b/drivers/gpu/drm/scheduler/sched_main.c
> index a48be16ab84f..9f614a775c49 100644
> --- a/drivers/gpu/drm/scheduler/sched_main.c
> +++ b/drivers/gpu/drm/scheduler/sched_main.c
> @@ -78,6 +78,8 @@
> #include <drm/gpu_scheduler.h>
> #include <drm/spsc_queue.h>
>
> +#include "sched_internal.h"
> +
> #define CREATE_TRACE_POINTS
> #include "gpu_scheduler_trace.h"
>
> @@ -87,9 +89,6 @@ static struct lockdep_map drm_sched_lockdep_map = {
> };
> #endif
>
> -#define to_drm_sched_job(sched_job) \
> - container_of((sched_job), struct drm_sched_job,
> queue_node)
> -
> int drm_sched_policy = DRM_SCHED_POLICY_FIFO;
>
> /**
> @@ -123,7 +122,7 @@ static bool drm_sched_can_queue(struct
> drm_gpu_scheduler *sched,
> {
> struct drm_sched_job *s_job;
>
> - s_job = to_drm_sched_job(spsc_queue_peek(&entity-
> >job_queue));
> + s_job = drm_sched_entity_queue_peek(entity);
> if (!s_job)
> return false;
>
