[PATCH v2 2/9] drm/xe: Add generic dependecy jobs / scheduler
Matthew Brost
matthew.brost at intel.com
Tue Jul 15 21:14:24 UTC 2025
On Tue, Jul 15, 2025 at 03:04:07PM -0600, Summers, Stuart wrote:
> On Wed, 2025-07-02 at 16:42 -0700, Matthew Brost wrote:
> > Add generic dependecy jobs / scheduler which serves as wrapper for
> > DRM
> > scheduler. Useful when we want delay a generic operation until a
> > dma-fence signals.
> >
> > Existing use cases could be destroying of resources based fences /
> > dma-resv, the preempt rebind worker, and pipelined GT TLB
> > invalidations.
> >
> > Written in such a way it could be moved to DRM subsystem if needed.
> >
> > Signed-off-by: Matthew Brost <matthew.brost at intel.com>
> > ---
> > drivers/gpu/drm/xe/Makefile | 1 +
> > drivers/gpu/drm/xe/xe_dep_job_types.h | 29 ++++++
> > drivers/gpu/drm/xe/xe_dep_scheduler.c | 145
> > ++++++++++++++++++++++++++
> > drivers/gpu/drm/xe/xe_dep_scheduler.h | 21 ++++
> > 4 files changed, 196 insertions(+)
> > create mode 100644 drivers/gpu/drm/xe/xe_dep_job_types.h
> > create mode 100644 drivers/gpu/drm/xe/xe_dep_scheduler.c
> > create mode 100644 drivers/gpu/drm/xe/xe_dep_scheduler.h
> >
> > diff --git a/drivers/gpu/drm/xe/Makefile
> > b/drivers/gpu/drm/xe/Makefile
> > index 1d97e5b63f4e..0edcfc770c0d 100644
> > --- a/drivers/gpu/drm/xe/Makefile
> > +++ b/drivers/gpu/drm/xe/Makefile
> > @@ -28,6 +28,7 @@ $(obj)/generated/%_wa_oob.c
> > $(obj)/generated/%_wa_oob.h: $(obj)/xe_gen_wa_oob \
> > xe-y += xe_bb.o \
> > xe_bo.o \
> > xe_bo_evict.o \
> > + xe_dep_scheduler.o \
> > xe_devcoredump.o \
> > xe_device.o \
> > xe_device_sysfs.o \
> > diff --git a/drivers/gpu/drm/xe/xe_dep_job_types.h
> > b/drivers/gpu/drm/xe/xe_dep_job_types.h
> > new file mode 100644
> > index 000000000000..c6a484f24c8c
> > --- /dev/null
> > +++ b/drivers/gpu/drm/xe/xe_dep_job_types.h
> > @@ -0,0 +1,29 @@
> > +/* SPDX-License-Identifier: MIT */
> > +/*
> > + * Copyright © 2025 Intel Corporation
> > + */
> > +
> > +#ifndef _XE_DEP_JOB_TYPES_H_
> > +#define _XE_DEP_JOB_TYPES_H_
> > +
> > +#include <drm/gpu_scheduler.h>
> > +
> > +struct xe_dep_job;
> > +
> > +/** struct xe_dep_job_ops - Generic Xe dependency job operations */
> > +struct xe_dep_job_ops {
> > + /** @run_job: Run generic Xe dependency job */
> > + struct dma_fence *(*run_job)(struct xe_dep_job *job);
> > + /** @free_job: Free generic Xe dependency job */
> > + void (*free_job)(struct xe_dep_job *job);
> > +};
> > +
> > +/** struct xe_dep_job - Generic dependency Xe job */
> > +struct xe_dep_job {
> > + /** @drm: base DRM scheduler job */
> > + struct drm_sched_job drm;
> > + /** @ops: dependency job operations */
> > + const struct xe_dep_job_ops *ops;
> > +};
> > +
> > +#endif
> > diff --git a/drivers/gpu/drm/xe/xe_dep_scheduler.c
> > b/drivers/gpu/drm/xe/xe_dep_scheduler.c
> > new file mode 100644
> > index 000000000000..fbd55577d787
> > --- /dev/null
> > +++ b/drivers/gpu/drm/xe/xe_dep_scheduler.c
> > @@ -0,0 +1,145 @@
> > +// SPDX-License-Identifier: MIT
> > +/*
> > + * Copyright © 2025 Intel Corporation
> > + */
> > +
> > +#include <linux/slab.h>
> > +
> > +#include <drm/gpu_scheduler.h>
> > +
> > +#include "xe_dep_job_types.h"
> > +#include "xe_dep_scheduler.h"
> > +#include "xe_device_types.h"
> > +
> > +/**
> > + * DOC: Xe Dependency Scheduler
> > + *
> > + * The Xe dependency scheduler is a simple wrapper built around the
> > DRM
> > + * scheduler to execute jobs once their dependencies are resolved
> > (i.e., all
> > + * input fences specified as dependencies are signaled). The jobs
> > that are
> > + * executed contain virtual functions to run (execute) and free the
> > job,
> > + * allowing a single dependency scheduler to handle jobs performing
> > different
> > + * operations.
> > + *
> > + * Example use cases include deferred resource freeing, TLB
> > invalidations after
> > + * bind jobs, etc.
> > + */
> > +
> > +/** struct xe_dep_scheduler - Generic Xe dependency scheduler */
> > +struct xe_dep_scheduler {
> > + /** @sched: DRM GPU scheduler */
> > + struct drm_gpu_scheduler sched;
> > + /** @entity: DRM scheduler entity */
> > + struct drm_sched_entity entity;
> > + /** @rcu: For safe freeing of exported dma fences */
> > + struct rcu_head rcu;
> > +};
> > +
> > +static struct dma_fence *xe_dep_scheduler_run_job(struct
> > drm_sched_job *drm_job)
> > +{
> > + struct xe_dep_job *dep_job =
> > + container_of(drm_job, typeof(*dep_job), drm);
> > +
> > + return dep_job->ops->run_job(dep_job);
> > +}
> > +
> > +static void xe_dep_scheduler_free_job(struct drm_sched_job *drm_job)
> > +{
> > + struct xe_dep_job *dep_job =
> > + container_of(drm_job, typeof(*dep_job), drm);
> > +
> > + dep_job->ops->free_job(dep_job);
> > +}
> > +
> > +static const struct drm_sched_backend_ops sched_ops = {
> > + .run_job = xe_dep_scheduler_run_job,
> > + .free_job = xe_dep_scheduler_free_job,
> > +};
> > +
> > +/**
> > + * xe_dep_scheduler_create() - Generic Xe dependency scheduler
> > create
> > + * @xe: Xe device
> > + * @submit_wq: Submit workqueue struct (can be NULL)
> > + * @name: Name of dependency scheduler
> > + * @job_limit: Max dependency jobs that can be scheduled
> > + *
> > + * Create a generic Xe dependency scheduler and initialize internal
> > DRM
> > + * scheduler objects.
> > + *
> > + * Return: Generic Xe dependency scheduler object or ERR_PTR
> > + */
> > +struct xe_dep_scheduler *
> > +xe_dep_scheduler_create(struct xe_device *xe,
> > + struct workqueue_struct *submit_wq,
> > + const char *name, u32 job_limit)
> > +{
> > + struct xe_dep_scheduler *dep_scheduler;
> > + struct drm_gpu_scheduler *sched;
> > + const struct drm_sched_init_args args = {
> > + .ops = &sched_ops,
> > + .submit_wq = submit_wq,
> > + .num_rqs = 1,
> > + .credit_limit = job_limit,
> > + .timeout = MAX_SCHEDULE_TIMEOUT,
> > + .name = name,
> > + .dev = xe->drm.dev,
> > + };
> > + int err;
> > +
> > + dep_scheduler = kzalloc(sizeof(*dep_scheduler), GFP_KERNEL);
> > + if (!dep_scheduler)
> > + return ERR_PTR(-ENOMEM);
> > +
> > + err = drm_sched_init(&dep_scheduler->sched, &args);
> > + if (err)
> > + goto err_free;
> > +
> > + sched = &dep_scheduler->sched;
> > + err = drm_sched_entity_init(&dep_scheduler->entity, 0,
> > + (struct drm_gpu_scheduler
> > **)&sched, 1,
>
> Why the cast here?
>
Copied from some existing code that had a cast, not needed it either
case. Will remove.
Matt
> Otherwise this patch lgtm.
>
> Thanks,
> Stuart
>
> > + NULL);
> > + if (err)
> > + goto err_sched;
> > +
> > + init_rcu_head(&dep_scheduler->rcu);
> > +
> > + return dep_scheduler;
> > +
> > +err_sched:
> > + drm_sched_fini(&dep_scheduler->sched);
> > +err_free:
> > + kfree(dep_scheduler);
> > +
> > + return ERR_PTR(err);
> > +}
> > +
> > +/**
> > + * xe_dep_scheduler_fini() - Generic Xe dependency scheduler
> > finalize
> > + * @dep_scheduler: Generic Xe dependency scheduler object
> > + *
> > + * Finalize internal DRM scheduler objects and free generic Xe
> > dependency
> > + * scheduler object
> > + */
> > +void xe_dep_scheduler_fini(struct xe_dep_scheduler *dep_scheduler)
> > +{
> > + drm_sched_entity_fini(&dep_scheduler->entity);
> > + drm_sched_fini(&dep_scheduler->sched);
> > + /*
> > + * RCU free due sched being exported via DRM scheduler fences
> > + * (timeline name).
> > + */
> > + kfree_rcu(dep_scheduler, rcu);
> > +}
> > +
> > +/**
> > + * xe_dep_scheduler_entity() - Retrieve a generic Xe dependency
> > scheduler
> > + * DRM scheduler entity
> > + * @dep_scheduler: Generic Xe dependency scheduler object
> > + *
> > + * Return: The generic Xe dependency scheduler's DRM scheduler
> > entity
> > + */
> > +struct drm_sched_entity *
> > +xe_dep_scheduler_entity(struct xe_dep_scheduler *dep_scheduler)
> > +{
> > + return &dep_scheduler->entity;
> > +}
> > diff --git a/drivers/gpu/drm/xe/xe_dep_scheduler.h
> > b/drivers/gpu/drm/xe/xe_dep_scheduler.h
> > new file mode 100644
> > index 000000000000..853961eec64b
> > --- /dev/null
> > +++ b/drivers/gpu/drm/xe/xe_dep_scheduler.h
> > @@ -0,0 +1,21 @@
> > +/* SPDX-License-Identifier: MIT */
> > +/*
> > + * Copyright © 2025 Intel Corporation
> > + */
> > +
> > +#include <linux/types.h>
> > +
> > +struct drm_sched_entity;
> > +struct workqueue_struct;
> > +struct xe_dep_scheduler;
> > +struct xe_device;
> > +
> > +struct xe_dep_scheduler *
> > +xe_dep_scheduler_create(struct xe_device *xe,
> > + struct workqueue_struct *submit_wq,
> > + const char *name, u32 job_limit);
> > +
> > +void xe_dep_scheduler_fini(struct xe_dep_scheduler *dep_scheduler);
> > +
> > +struct drm_sched_entity *
> > +xe_dep_scheduler_entity(struct xe_dep_scheduler *dep_scheduler);
>
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