On Wed, 2025-02-12 at 09:32 +0000, Tvrtko Ursulin wrote:
>
> On 12/02/2025 09:02, Philipp Stanner wrote:
> > 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.
> > ""
>
> Returns before the description would be yet another new style, no?
> I's
> say that if we are churning lets follow
> Documentation/doc-guide/kernel-doc.rst.
Oh yes, you are right – official guideline demands "Return:" at the
end. So let's go for that for contributions.
P.
> Or even consider sending a patch
> which churns everything at once.
>
> Regards,
>
> Tvrtko
>
> > > + */
> > > +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;
> > >
> >
>
