On Wed, Jul 7, 2021 at 12:15 AM Christoph Hellwig hch@infradead.org wrote:

On Wed, Jul 07, 2021 at 09:10:26AM +0200, Christian K??nig wrote:

...

Well, the original code all this is based on already had the comment that this really belong into the page allocator.

The key point is traditionally only GPUs used uncached and write-combined memory in such large quantities that having a pool for them makes sense.

Because of this we had this separately to reduce the complexity in the page allocator to handle another set of complexity of allocation types.

For the upside, for those use cases it means huge performance improvements for those drivers. See the numbers John provided in the cover letter.

But essentially at least I would be totally fine moving this into the page allocator, but moving it outside of TTM already helps with this goal. So this patch set is certainly a step into the right direction.

Unless I'm badly misreading the patch and this series there is nothing about cache attributes in this code. It just allocates pages, zeroes them, eventually hands them out to a consumer and registers a shrinker for its freelist.

If OTOH it actually dealt with cachability that should be documented in the commit log and probably also the naming of the implementation.

So the cache attributes are still managed in the tmm_pool code. This series just pulls the pool/shrinker management out into common code so we can use it in the dmabuf heap code without duplicating things.

thanks -john