linux-kernel - Re: [RFC PATCH 7/7] drm/panfrost/panthor: Take sparse objects into account for fdinfo

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Message-ID: <20250225160908.4c5a8a41@collabora.com>
Date: Tue, 25 Feb 2025 16:09:08 +0100
From: Boris Brezillon <boris.brezillon@...labora.com>
To: Adrián Larumbe <adrian.larumbe@...labora.com>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, Steven
 Price <steven.price@....com>, Rob Herring <robh@...nel.org>, Maarten
 Lankhorst <maarten.lankhorst@...ux.intel.com>, Maxime Ripard
 <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, David Airlie
 <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, Liviu Dudau
 <liviu.dudau@....com>, kernel@...labora.com
Subject: Re: [RFC PATCH 7/7] drm/panfrost/panthor: Take sparse objects into
 account for fdinfo

On Tue, 18 Feb 2025 23:25:37 +0000
Adrián Larumbe <adrian.larumbe@...labora.com> wrote:

> Because of the alternative definition of the 'pages' field in shmem after adding
> support for sparse allocations, the logic for deciding whether pages are
> available must be expanded.
> 
> Signed-off-by: Adrián Larumbe <adrian.larumbe@...labora.com>
> ---
>  drivers/gpu/drm/panfrost/panfrost_gem.c | 4 +++-
>  drivers/gpu/drm/panthor/panthor_gem.c   | 4 +++-
>  2 files changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.c b/drivers/gpu/drm/panfrost/panfrost_gem.c
> index 0cda2c4e524f..ced2fdee74ab 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_gem.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_gem.c
> @@ -200,7 +200,9 @@ static enum drm_gem_object_status panfrost_gem_status(struct drm_gem_object *obj
>  	struct panfrost_gem_object *bo = to_panfrost_bo(obj);
>  	enum drm_gem_object_status res = 0;
>  
> -	if (bo->base.base.import_attach || bo->base.pages)
> +	if (bo->base.base.import_attach ||
> +	    (!bo->base.sparse && bo->base.pages) ||
> +	    (bo->base.sparse && !xa_empty(&bo->base.xapages)))
>  		res |= DRM_GEM_OBJECT_RESIDENT;

Looks like we want some kind of drm_gem_shmem_is_populated() helper,
and have all drivers doing this pages != NULL test patched to use this
new helper as part of the patch introducing sparse shmem GEMs.

>  
>  	if (bo->base.madv == PANFROST_MADV_DONTNEED)
> diff --git a/drivers/gpu/drm/panthor/panthor_gem.c b/drivers/gpu/drm/panthor/panthor_gem.c
> index 8244a4e6c2a2..8dbaf766bd79 100644
> --- a/drivers/gpu/drm/panthor/panthor_gem.c
> +++ b/drivers/gpu/drm/panthor/panthor_gem.c
> @@ -155,7 +155,9 @@ static enum drm_gem_object_status panthor_gem_status(struct drm_gem_object *obj)
>  	struct panthor_gem_object *bo = to_panthor_bo(obj);
>  	enum drm_gem_object_status res = 0;
>  
> -	if (bo->base.base.import_attach || bo->base.pages)
> +	if (bo->base.base.import_attach ||
> +	    (!bo->base.sparse && bo->base.pages) ||
> +	    (bo->base.sparse && !xa_empty(&bo->base.xapages)))
>  		res |= DRM_GEM_OBJECT_RESIDENT;
>  
>  	return res;