[Intel-gfx] [PATCH 02/15] drm/i915: enable THP for gemfs

[Joonas Lahtinen]

On ke, 2017-05-31 at 19:51 +0100, Matthew Auld wrote:
> Enable transparent-huge-pages through gemfs by mounting with
> huge=within_size.
> 
> Signed-off-by: Matthew Auld <matthew.auld at intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>

<SNIP>

> @@ -41,6 +42,28 @@ struct vfsmount *i915_gemfs_create(void)
>  
>  	gemfs_mnt = kern_mount(type);
>  
> +#if defined(CONFIG_TRANSPARENT_HUGE_PAGECACHE)
> +	if (!IS_ERR(gemfs_mnt) && has_transparent_hugepage()) {
> +		struct super_block *sb = gemfs_mnt->mnt_sb;
> +		char options[] = "huge=within_size";
> +		int flags = 0;
> +		int ret;
> +
> +		/* Idealy we would just pass the mount options when mounting,
> +		 * but for some reason shmem chooses not to parse the options
> +		 * for MS_KERNMOUNT, probably because shm_mnt is the only tmpfs
> +		 * kernel mount other than this, where the mount options aren't
> +		 * used. To workaround this we do a remount, which is fairly
> +		 * inexpensive, where we know the options are never igonored.
> +		 */
> +		ret = sb->s_op->remount_fs(sb, &flags, options);

This sounds like a bugfix to be sent.

Regards, Joonas
-- 
Joonas Lahtinen
Open Source Technology Center
Intel Corporation