Re: [PATCH 02/21] drm/i915: introduce simple gemfs

[Joonas Lahtinen <joonas.lahtinen@linux.intel.com>]

On Fri, 2017-09-29 at 17:10 +0100, Matthew Auld wrote:
> Not a fully blown gemfs, just our very own tmpfs kernel mount. Doing so
> moves us away from the shmemfs shm_mnt, and gives us the much needed
> flexibility to do things like set our own mount options, namely huge=
> which should allow us to enable the use of transparent-huge-pages for
> our shmem backed objects.
> 
> v2: various improvements suggested by Joonas
> 
> v3: move gemfs instance to i915.mm and simplify now that we have
> file_setup_with_mnt
> 
> v4: fallback to tmpfs shm_mnt upon failure to setup gemfs
> 
> v5: make tmpfs fallback kinder
> 
> Signed-off-by: Matthew Auld <matthew.auld@intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Dave Hansen <dave.hansen@intel.com>
> Cc: Kirill A. Shutemov <kirill@shutemov.name>
> Cc: Hugh Dickins <hughd@google.com>
> Cc: linux-mm@kvack.org

<SNIP>

> @@ -4251,6 +4252,29 @@ static const struct drm_i915_gem_object_ops i915_gem_object_ops = {
>  	.pwrite = i915_gem_object_pwrite_gtt,
>  };
>  
> +static int i915_gem_object_create_shmem(struct drm_device *dev,
> +					struct drm_gem_object *obj,
> +					size_t size)
> +{
> +	struct drm_i915_private *i915 = to_i915(dev);
> +	struct file *filp;
> +
> +	drm_gem_private_object_init(dev, obj, size);
> +
> +	if (i915->mm.gemfs)
> +		filp = shmem_file_setup_with_mnt(i915->mm.gemfs, "i915", size,
> +						 VM_NORESERVE);
> +	else
> +		filp = shmem_file_setup("i915", size, VM_NORESERVE);

Put that VM_NORESERVE to 'flags' variable.

> @@ -4915,6 +4939,9 @@ i915_gem_load_init(struct drm_i915_private *dev_priv)
>  
>  	spin_lock_init(&dev_priv->fb_tracking.lock);
>  
> +	if (i915_gemfs_init(dev_priv))
> +		DRM_NOTE("Unable to create a private tmpfs mountpoint, hugepage support will be disabled.\n");

s/mountpoint/mount/, as we're not creating a directory. Maybe also
include the returned error for easier post-mortem?

Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

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

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