Re: [PATCH 1/3] drm/ttm: Issue direct reclaim at beneficial_order

["Thomas Hellström" <thomas.hellstrom@linux.intel.com>]

On Thu, 2026-04-30 at 10:11 +1000, Dave Airlie wrote:
> > 
> > Probably stupid question: for systems like my Lunar Lake Xe2, which
> > has
> > unified memory and (IIUC) no special cache-type or write-mode
> > constraints for GPU mappings, would it be possible to use regular
> > system-provided pages (e.g. from shmem) instead of going through
> > the TTM
> > pool and allow mTHP to provide the aligned and contiguous backing
> > storage that the GPU wants? Something like GEM has, but maybe
> > inside the
> > TTM API?
> 
> TTM pool doesn't get used for system memory allocations in that case,
> if you are asking for cached memory.

Both Lunar Lake and Panther Lake use write-combined memory for buffer
objects in performance-critical paths. So the pools are indeed getting
used.

And while it is possible to change caching on shmem pages if they are
pinned/unevictable, trying to pool them quickly becomes messy.

/Thomas


> 
> Dave.