[Intel-gfx] [PATCH 06/17] mm/shmem: expose driver overridable huge option

[Kirill A. Shutemov]

On Tue, May 16, 2017 at 09:29:37AM +0100, Matthew Auld wrote:
> In i915 we are aiming to support huge GTT pages for the GPU, and to
> complement this we also want to enable THP for our shmem backed objects.
> Even though THP is supported in shmemfs it can only be enabled through
> the huge= mount option, but for users of the kernel mounted shm_mnt like
> i915, we are a little stuck. There is the sysfs knob shmem_enabled to
> either forcefully enable/disable the feature, but that seems to only be
> useful for testing purposes. What we propose is to expose a driver
> overridable huge option as part of shmem_inode_info to control the use
> of THP for a given mapping.

I don't like this. It's kinda hacky.

Is there a reason why i915 cannot mount a new tmpfs for own use?

Or other option would be to change default to SHMEM_HUGE_ADVISE and wire
up fadvise handle to control per-file allocation policy.

-- 
 Kirill A. Shutemov