On Tue, May 07, 2024 at 01:18:57PM -0300, Jason Gunthorpe wrote:

On Tue, May 07, 2024 at 05:05:12PM +0100, Pavel Begunkov wrote:

quoted

quoted

even in tree if you give them enough rope, and they should not have
that rope when the only sensible options are page/folio based kernel
memory (incuding large/huge folios) and dmabuf.

I believe there is at least one deep confusion here, considering you
previously mentioned Keith's pre-mapping patches. The "hooks" are not
that about in what format you pass memory, it's arguably the least
interesting part for page pool, more or less it'd circulate whatever
is given. It's more of how to have a better control over buffer lifetime
and implement a buffer pool passing data to users and empty buffers
back.

Isn't that more or less exactly what dmabuf is? Why do you need
another almost dma-buf thing for another project?

That's the exact point I've been making since the last round of
the series.  We don't need to reinvent dmabuf poorly in every
subsystem, but instead fix the odd parts in it and make it suitable
for everyone.