Re: page pools, was Re: [PATCH v9 1/5] drm: Add a sharable drm page-pool implementation

From: Christoph Hellwig
Date: Thu Jul 08 2021 - 00:21:26 EST

On Wed, Jul 07, 2021 at 12:35:23PM -0700, John Stultz wrote:
> So, as Christian mentioned, on the TTM side it's useful, as they are
> trying to avoid TLB flushes when changing caching attributes.
> For the dmabuf system heap purposes, the main benefit is moving the
> page zeroing to the free path, rather than the allocation path. This
> on its own doesn't save much, but allows us to defer frees (and thus
> the zeroing) to the background, which can get that work out of the hot
> path.

I really do no think that is worth it to fragment the free pages.