From mboxrd@z Thu Jan  1 00:00:00 1970
From: Shakeel Butt <shakeelb-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Subject: Re: [PATCH 0/4] Track exported dma-buffers with memcg
Date: Thu, 12 Jan 2023 08:13:37 +0000
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To: "T.J. Mercier" <tjmercier-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Cc: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Zefan Li <lizefan.x-EC8Uxl6Npydl57MIdRCFDg@public.gmane.org>, Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>, Jonathan Corbet <corbet-T1hC0tSOHrs@public.gmane.org>, Greg Kroah-Hartman <gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>, Arve =?utf-8?B?SGrDuG5uZXbDpWc=?= <arve-z5hGa2qSFaRBDgjK7y7TUQ@public.gmane.org>, Todd Kjos <tkjos-z5hGa2qSFaRBDgjK7y7TUQ@public.gmane.org>, Martijn Coenen <maco-z5hGa2qSFaRBDgjK7y7TUQ@public.gmane.org>, Joel Fernandes <joel-QYYGw3jwrUn5owFQY34kdNi2O/JbrIOy@public.gmane.org>, Christian Brauner <brauner-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Carlos Llamas <cmllamas-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Suren Baghdasaryan <surenb-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Sumit Semwal <sumit.semwal-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>, Christian =?utf-8?B?S8O2bmln?= <christian.koenig-5C7GfCeVMHo@public.gmane.org>, Michal Hocko <mhocko-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Roman Gushchin <roman.gushchin-fxUVXftIFDnyG1zEObXtfA@public.gmane.org>, Muchun Song <muchun.song-fxUVXftIFDnyG1zEObXtfA@public.gmane.org>, Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, Paul Moore <paul-r2n+y4ga6xFZroRs9YW3xA@public.gmane.org>

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?