[PATCH v3 8/8] drm/v3d: Add modparam for turning off Big/Super Pages

[Tvrtko Ursulin]

On 21/04/2024 22:44, Maíra Canal wrote:
> Add a modparam for turning off Big/Super Pages to make sure that if an
> user doesn't want Big/Super Pages enabled, it can disabled it by setting
> the modparam to false.
> 
> Signed-off-by: Maíra Canal <mcanal at igalia.com>
> ---
>   drivers/gpu/drm/v3d/v3d_drv.c   | 8 ++++++++
>   drivers/gpu/drm/v3d/v3d_gemfs.c | 5 +++++
>   2 files changed, 13 insertions(+)
> 
> diff --git a/drivers/gpu/drm/v3d/v3d_drv.c b/drivers/gpu/drm/v3d/v3d_drv.c
> index 3debf37e7d9b..bc8c8905112a 100644
> --- a/drivers/gpu/drm/v3d/v3d_drv.c
> +++ b/drivers/gpu/drm/v3d/v3d_drv.c
> @@ -36,6 +36,14 @@
>   #define DRIVER_MINOR 0
>   #define DRIVER_PATCHLEVEL 0
>   
> +bool super_pages = true;
> +
> +/* Only expose the `super_pages` modparam if THP is enabled. */
> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE

I would have put bool super_pages in here so it can get compiled out.

> +module_param_named(super_pages, super_pages, bool, 0400);
> +MODULE_PARM_DESC(super_pages, "Enable/Disable Super Pages support.");
> +#endif
> +
>   static int v3d_get_param_ioctl(struct drm_device *dev, void *data,
>   			       struct drm_file *file_priv)
>   {
> diff --git a/drivers/gpu/drm/v3d/v3d_gemfs.c b/drivers/gpu/drm/v3d/v3d_gemfs.c
> index 31cf5bd11e39..5fa08263cff2 100644
> --- a/drivers/gpu/drm/v3d/v3d_gemfs.c
> +++ b/drivers/gpu/drm/v3d/v3d_gemfs.c
> @@ -11,6 +11,11 @@ void v3d_gemfs_init(struct v3d_dev *v3d)
>   	char huge_opt[] = "huge=within_size";
>   	struct file_system_type *type;
>   	struct vfsmount *gemfs;
> +	extern bool super_pages;
> +
> +	/* The user doesn't want to enable Super Pages */
> +	if (!super_pages)
> +		goto err;

And if this hunk is moved after the CONFIG_TRANSPARENT_HUGEPAGE check 
just below I hope compiler can be happy with that.

Regards,

Tvrtko

>   
>   	/*
>   	 * By creating our own shmemfs mountpoint, we can pass in