Re: [Intel-gfx] [PATCH v9 04/17] drm/i915/pxp: allocate a vcs context for pxp usage

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Wed, Sep 15, 2021 at 04:53:35PM +0300, Jani Nikula wrote:
> On Fri, 10 Sep 2021, Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com> wrote:
> > diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp.h b/drivers/gpu/drm/i915/pxp/intel_pxp.h
> > new file mode 100644
> > index 000000000000..e87550fb9821
> > --- /dev/null
> > +++ b/drivers/gpu/drm/i915/pxp/intel_pxp.h
> > @@ -0,0 +1,35 @@
> > +/* SPDX-License-Identifier: MIT */
> > +/*
> > + * Copyright(c) 2020, Intel Corporation. All rights reserved.
> > + */
> > +
> > +#ifndef __INTEL_PXP_H__
> > +#define __INTEL_PXP_H__
> > +
> > +#include "gt/intel_gt_types.h"
> 
> I've been trying to promote the idea that we don't include headers from
> headers, unless really necessary. It helps with build times by reducing
> rebuilds due to changes, but more importantly, it helps with coming up
> with abstractions that don't need to look at the guts of other
> components.
> 
> The above include line pulls in 67 other includes. And it has to look at
> the same files a *lot* more times to know not to include them again.
> 
> Maybe we need to start being more aggressive about hiding the
> abstractions behind the interfaces and headers. Static inlines are
> nothing but micro-optimizations that leak abstractions. Do we need
> these?

Yeap, we have a few cases where this is already happening...

Should we start using the container_of more directly and avoid the a_to_b()
helpers?

Should we create the a_to_b() helpers only inside .c files like we have
in a few other cases?

In this pxp case here it looks like using the container of directly is
everywhere is better... is this your recommendation?

> 
> > +#include "intel_pxp_types.h"
> > +
> > +static inline struct intel_gt *pxp_to_gt(const struct intel_pxp *pxp)
> > +{
> > +	return container_of(pxp, struct intel_gt, pxp);
> > +}
> 
> I think it's questionable to claim the parameter is const, when you can
> do:
> 
> 	const struct intel_pxp *const_pxp = something;
> 	struct intel_pxp *pxp = &pxp_to_gt(const_pxp)->pxp;
> 
> BR,
> Jani.
> 
> > +
> > +static inline bool intel_pxp_is_enabled(const struct intel_pxp *pxp)
> > +{
> > +	return pxp->ce;
> > +}
> > +
> > +#ifdef CONFIG_DRM_I915_PXP
> > +void intel_pxp_init(struct intel_pxp *pxp);
> > +void intel_pxp_fini(struct intel_pxp *pxp);
> > +#else
> > +static inline void intel_pxp_init(struct intel_pxp *pxp)
> > +{
> > +}
> > +
> > +static inline void intel_pxp_fini(struct intel_pxp *pxp)
> > +{
> > +}
> > +#endif
> > +
> > +#endif /* __INTEL_PXP_H__ */
> > diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_types.h b/drivers/gpu/drm/i915/pxp/intel_pxp_types.h
> > new file mode 100644
> > index 000000000000..bd12c520e60a
> > --- /dev/null
> > +++ b/drivers/gpu/drm/i915/pxp/intel_pxp_types.h
> > @@ -0,0 +1,15 @@
> > +/* SPDX-License-Identifier: MIT */
> > +/*
> > + * Copyright(c) 2020, Intel Corporation. All rights reserved.
> > + */
> > +
> > +#ifndef __INTEL_PXP_TYPES_H__
> > +#define __INTEL_PXP_TYPES_H__
> > +
> > +struct intel_context;
> > +
> > +struct intel_pxp {
> > +	struct intel_context *ce;
> > +};
> > +
> > +#endif /* __INTEL_PXP_TYPES_H__ */
> 
> -- 
> Jani Nikula, Intel Open Source Graphics Center