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Date:   Tue, 12 Sep 2023 11:29:52 +0200
From:   Boris Brezillon <boris.brezillon@collabora.com>
To:     =?UTF-8?B?QWRyacOhbg==?= Larumbe <adrian.larumbe@collabora.com>
Cc:     maarten.lankhorst@linux.intel.com, mripard@kernel.org,
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        dmitry.baryshkov@linaro.org, sean@poorly.run,
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        steven.price@arm.com, linux-arm-msm@vger.kernel.org,
        linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
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        freedreno@lists.freedesktop.org
Subject: Re: [PATCH v4 5/6] drm/panfrost: Implement generic DRM object RSS
 reporting function
Message-ID: <20230912112952.1fc608f4@collabora.com>
In-Reply-To: <20230912084044.955864-6-adrian.larumbe@collabora.com>
References: <20230912084044.955864-1-adrian.larumbe@collabora.com>
        <20230912084044.955864-6-adrian.larumbe@collabora.com>
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On Tue, 12 Sep 2023 09:36:59 +0100
Adri=C3=A1n Larumbe <adrian.larumbe@collabora.com> wrote:

> BO's RSS is updated every time new pages are allocated on demand and mapp=
ed
> for the object at GPU page fault's IRQ handler, but only for heap buffers.
> The reason this is unnecessary for non-heap buffers is that they are mapp=
ed
> onto the GPU's VA space and backed by physical memory in their entirety at
> BO creation time.
>=20
> This calculation is unnecessary for imported PRIME objects, since heap
> buffers cannot be exported by our driver, and the actual BO RSS size is t=
he
> one reported in its attached dmabuf structure.
>=20
> Signed-off-by: Adri=C3=A1n Larumbe <adrian.larumbe@collabora.com>

Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>

> ---
>  drivers/gpu/drm/panfrost/panfrost_gem.c | 15 +++++++++++++++
>  drivers/gpu/drm/panfrost/panfrost_gem.h |  5 +++++
>  drivers/gpu/drm/panfrost/panfrost_mmu.c |  1 +
>  3 files changed, 21 insertions(+)
>=20
> diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.c b/drivers/gpu/drm/pa=
nfrost/panfrost_gem.c
> index 7d8f83d20539..4365434b48db 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_gem.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_gem.c
> @@ -208,6 +208,20 @@ static enum drm_gem_object_status panfrost_gem_statu=
s(struct drm_gem_object *obj
>  	return res;
>  }
> =20
> +static size_t panfrost_gem_rss(struct drm_gem_object *obj)
> +{
> +	struct panfrost_gem_object *bo =3D to_panfrost_bo(obj);
> +
> +	if (bo->is_heap) {
> +		return bo->heap_rss_size;
> +	} else if (bo->base.pages) {
> +		WARN_ON(bo->heap_rss_size);
> +		return bo->base.base.size;
> +	} else {
> +		return 0;
> +	}
> +}
> +
>  static const struct drm_gem_object_funcs panfrost_gem_funcs =3D {
>  	.free =3D panfrost_gem_free_object,
>  	.open =3D panfrost_gem_open,
> @@ -220,6 +234,7 @@ static const struct drm_gem_object_funcs panfrost_gem=
_funcs =3D {
>  	.vunmap =3D drm_gem_shmem_object_vunmap,
>  	.mmap =3D drm_gem_shmem_object_mmap,
>  	.status =3D panfrost_gem_status,
> +	.rss =3D panfrost_gem_rss,
>  	.vm_ops =3D &drm_gem_shmem_vm_ops,
>  };
> =20
> diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.h b/drivers/gpu/drm/pa=
nfrost/panfrost_gem.h
> index ad2877eeeccd..13c0a8149c3a 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_gem.h
> +++ b/drivers/gpu/drm/panfrost/panfrost_gem.h
> @@ -36,6 +36,11 @@ struct panfrost_gem_object {
>  	 */
>  	atomic_t gpu_usecount;
> =20
> +	/*
> +	 * Object chunk size currently mapped onto physical memory
> +	 */
> +	size_t heap_rss_size;
> +
>  	bool noexec		:1;
>  	bool is_heap		:1;
>  };
> diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c b/drivers/gpu/drm/pa=
nfrost/panfrost_mmu.c
> index d54d4e7b2195..7b1490cdaa48 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_mmu.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c
> @@ -522,6 +522,7 @@ static int panfrost_mmu_map_fault_addr(struct panfros=
t_device *pfdev, int as,
>  		   IOMMU_WRITE | IOMMU_READ | IOMMU_NOEXEC, sgt);
> =20
>  	bomapping->active =3D true;
> +	bo->heap_rss_size +=3D SZ_2;
> =20
>  	dev_dbg(pfdev->dev, "mapped page fault @ AS%d %llx", as, addr);
> =20