Re: [PATCH 0/4] Track exported dma-buffers with memcg

[Christian König]

Am 12.01.23 um 09:13 schrieb Shakeel Butt:
> On Wed, Jan 11, 2023 at 04:49:36PM -0800, T.J. Mercier wrote:
> [...]
> > > The problem is a bit that with gpu allocations reclaim is essentially "we
> > > pass the error to userspace and they get to sort the mess out". There are
> > > some exceptions (some gpu drivers to have shrinkers) would we need to make
> > > sure these shrinkers are tied into the cgroup stuff before we could enable
> > > charging for them?
> > I'm also not sure that we can depend on the dmabuf being backed at
> > export time 100% of the time? (They are for dmabuf heaps.) If not,
> > that'd make calling the existing memcg folio based functions a bit
> > difficult.
> Where does the actual memory get allocated? I see the first patch is
> updating the stat in dma_buf_export() and dma_buf_release(). Does the
> memory get allocated and freed in those code paths?

Nope, dma_buf_export() just makes the memory available to others.

The driver which calls dma_buf_export() is the one allocating the memory.

Regards,
Christian.