Re: [PATCH v10 06/10] drm/v3d: Use huge tmpfs mountpoint helpers

["Maíra Canal" <mcanal@igalia.com>]

Hi Loïc,

On 28/11/25 15:52, Loïc Molinari wrote:
> Make use of the new drm_gem_huge_mnt_create() and
> drm_gem_get_huge_mnt() helpers to avoid code duplication. Now that
> it's just a few lines long, the single function in v3d_gemfs.c is
> moved into v3d_gem.c.
> 
> v3:
> - use huge tmpfs mountpoint in drm_device
> - move v3d_gemfs.c into v3d_gem.c
> 
> v4:
> - clean up mountpoint creation error handling
> 
> v5:
> - fix CONFIG_TRANSPARENT_HUGEPAGE check
> - use drm_gem_has_huge_mnt() helper
> 
> v8:
> - don't access huge_mnt field with CONFIG_TRANSPARENT_HUGEPAGE=n
> 
> v9:
> - replace drm_gem_has_huge_mnt() by drm_gem_get_huge_mnt()
> 
> v10:
> - get rid of CONFIG_TRANSPARENT_HUGEPAGE ifdefs
> 
> Signed-off-by: Loïc Molinari <loic.molinari@collabora.com>

Reviewed-by: Maíra Canal <mcanal@igalia.com>

With one suggestion below:

> ---
>   drivers/gpu/drm/v3d/Makefile    |  3 +-
>   drivers/gpu/drm/v3d/v3d_bo.c    |  5 ++-
>   drivers/gpu/drm/v3d/v3d_drv.c   |  2 +-
>   drivers/gpu/drm/v3d/v3d_drv.h   | 11 +-----
>   drivers/gpu/drm/v3d/v3d_gem.c   | 27 ++++++++++++--
>   drivers/gpu/drm/v3d/v3d_gemfs.c | 62 ---------------------------------
>   6 files changed, 30 insertions(+), 80 deletions(-)
>   delete mode 100644 drivers/gpu/drm/v3d/v3d_gemfs.c
> 

[...]

> diff --git a/drivers/gpu/drm/v3d/v3d_gem.c b/drivers/gpu/drm/v3d/v3d_gem.c
> index 5a180dc6c452..62532a89dd14 100644
> --- a/drivers/gpu/drm/v3d/v3d_gem.c
> +++ b/drivers/gpu/drm/v3d/v3d_gem.c
> @@ -259,6 +259,30 @@ v3d_invalidate_caches(struct v3d_dev *v3d)
>   	v3d_invalidate_slices(v3d, 0);
>   }
>   
> +static void
> +v3d_huge_mnt_init(struct v3d_dev *v3d)
> +{
> +	int err = 0;
> +
> +	/*
> +	 * By using a huge shmemfs mountpoint when the user wants to
> +	 * enable Super Pages, we can pass in mount flags that better
> +	 * match our usecase.
> +	 */

I feel that this comment is phrased in a way that isn’t very clear. If
possible, could you rephrase it or remove it? I think this comment is
no longer needed given all the documentation already added to the
DRM GEM functions.

Best Regards,
- Maíra

> +
> +	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && super_pages)
> +		err = drm_gem_huge_mnt_create(&v3d->drm, "within_size");
> +
> +	if (drm_gem_get_huge_mnt(&v3d->drm))
> +		drm_info(&v3d->drm, "Using Transparent Hugepages\n");
> +	else if (err)
> +		drm_warn(&v3d->drm, "Can't use Transparent Hugepages (%d)\n",
> +			 err);
> +	else
> +		drm_notice(&v3d->drm,
> +			   "Transparent Hugepage support is recommended for optimal performance on this platform!\n");
> +}
> +