[PATCH] drm/sched: Use struct for drm_sched_init() params

[Philipp Stanner]

On Thu, 2025-01-23 at 08:10 -0300, Maíra Canal wrote:
> Hi Philipp,
> 
> On 23/01/25 05:10, Philipp Stanner wrote:
> > On Wed, 2025-01-22 at 19:07 -0300, Maíra Canal wrote:
> > > Hi Philipp,
> > > 
> > > On 22/01/25 11:08, Philipp Stanner wrote:
> > > > drm_sched_init() has a great many parameters and upcoming new
> > > > functionality for the scheduler might add even more. Generally,
> > > > the
> > > > great number of parameters reduces readability and has already
> > > > caused
> > > > one missnaming in:
> > > > 
> > > > commit 6f1cacf4eba7 ("drm/nouveau: Improve variable name in
> > > > nouveau_sched_init()").
> > > > 
> > > > Introduce a new struct for the scheduler init parameters and
> > > > port
> > > > all
> > > > users.
> > > > 
> > > > Signed-off-by: Philipp Stanner <phasta at kernel.org>
> 
> [...]
> 
> > > 
> > > > diff --git a/drivers/gpu/drm/v3d/v3d_sched.c
> > > > b/drivers/gpu/drm/v3d/v3d_sched.c
> > > > index 99ac4995b5a1..716e6d074d87 100644
> > > > --- a/drivers/gpu/drm/v3d/v3d_sched.c
> > > > +++ b/drivers/gpu/drm/v3d/v3d_sched.c
> > > > @@ -814,67 +814,124 @@ static const struct
> > > > drm_sched_backend_ops
> > > > v3d_cpu_sched_ops = {
> > > >    	.free_job = v3d_cpu_job_free
> > > >    };
> > > >    
> > > > +/*
> > > > + * v3d's scheduler instances are all identical, except for ops
> > > > and
> > > > name.
> > > > + */
> > > > +static void
> > > > +v3d_common_sched_init(struct drm_sched_init_params *params,
> > > > struct
> > > > device *dev)
> > > > +{
> > > > +	memset(params, 0, sizeof(struct
> > > > drm_sched_init_params));
> > > > +
> > > > +	params->submit_wq = NULL; /* Use the system_wq. */
> > > > +	params->num_rqs = DRM_SCHED_PRIORITY_COUNT;
> > > > +	params->credit_limit = 1;
> > > > +	params->hang_limit = 0;
> > > > +	params->timeout = msecs_to_jiffies(500);
> > > > +	params->timeout_wq = NULL; /* Use the system_wq. */
> > > > +	params->score = NULL;
> > > > +	params->dev = dev;
> > > > +}
> > > 
> > > Could we use only one function that takes struct v3d_dev *v3d,
> > > enum
> > > v3d_queue, and sched_ops as arguments (instead of one function
> > > per
> > > queue)? You can get the name of the scheduler by concatenating
> > > "v3d_"
> > > to
> > > the return of v3d_queue_to_string().
> > > 
> > > I believe it would make the code much simpler.
> > 
> > Hello,
> > 
> > so just to get that right:
> > You'd like to have one universal function that switch-cases over an
> > enum, sets the ops and creates the name with string concatenation?
> > 
> > I'm not convinced that this is simpler than a few small functions,
> > but
> > it's not my component, so…
> > 
> > Whatever we'll do will be simpler than the existing code, though.
> > Right
> > now no reader can see at first glance whether all those schedulers
> > are
> > identically parametrized or not.
> > 
> 
> This is my proposal (just a quick draft, please check if it
> compiles):
> 
> diff --git a/drivers/gpu/drm/v3d/v3d_sched.c 
> b/drivers/gpu/drm/v3d/v3d_sched.c
> index 961465128d80..7cc45a0c6ca0 100644
> --- a/drivers/gpu/drm/v3d/v3d_sched.c
> +++ b/drivers/gpu/drm/v3d/v3d_sched.c
> @@ -820,67 +820,62 @@ static const struct drm_sched_backend_ops 
> v3d_cpu_sched_ops = {
>          .free_job = v3d_cpu_job_free
>   };
> 
> +static int
> +v3d_sched_queue_init(struct v3d_dev *v3d, enum v3d_queue queue,
> +                    const struct drm_sched_backend_ops *ops, const

Is it a queue, though?

How about _v3d_sched_init()?

P.

> char 
> *name)
> +{
> +       struct drm_sched_init_params params = {
> +               .submit_wq = NULL,
> +               .num_rqs = DRM_SCHED_PRIORITY_COUNT,
> +               .credit_limit = 1,
> +               .hang_limit = 0,
> +               .timeout = msecs_to_jiffies(500),
> +               .timeout_wq = NULL,
> +               .score = NULL,
> +               .dev = v3d->drm.dev,
> +       };
> +
> +       params.ops = ops;
> +       params.name = name;
> +
> +       return drm_sched_init(&v3d->queue[queue].sched, &params);
> +}
> +
>   int
>   v3d_sched_init(struct v3d_dev *v3d)
>   {
> -       int hw_jobs_limit = 1;
> -       int job_hang_limit = 0;
> -       int hang_limit_ms = 500;
>          int ret;
> 
> -       ret = drm_sched_init(&v3d->queue[V3D_BIN].sched,
> -                            &v3d_bin_sched_ops, NULL,
> -                            DRM_SCHED_PRIORITY_COUNT,
> -                            hw_jobs_limit, job_hang_limit,
> -                            msecs_to_jiffies(hang_limit_ms), NULL,
> -                            NULL, "v3d_bin", v3d->drm.dev);
> +       ret = v3d_sched_queue_init(v3d, V3D_BIN, &v3d_bin_sched_ops,
> +                                  "v3d_bin");
>          if (ret)
>                  return ret;
> 
> -       ret = drm_sched_init(&v3d->queue[V3D_RENDER].sched,
> -                            &v3d_render_sched_ops, NULL,
> -                            DRM_SCHED_PRIORITY_COUNT,
> -                            hw_jobs_limit, job_hang_limit,
> -                            msecs_to_jiffies(hang_limit_ms), NULL,
> -                            NULL, "v3d_render", v3d->drm.dev);
> +       ret = v3d_sched_queue_init(v3d, V3D_RENDER,
> &v3d_render_sched_ops,
> +                                  "v3d_render");
>          if (ret)
>                  goto fail;
> 
> [...]
> 
> At least for me, this looks much simpler than one function for each
> V3D queue.
> 
> Best Regards,
> - Maíra
> 
> > P.
> > 
> > 
> > > 
> > > Best Regards,
> > > - Maíra
> > > 
>