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References: <20210205080621.3102035-1-john.stultz@linaro.org> <0864e2a8-3a44-e7db-828f-abdac7c64471@amd.com>
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From:   John Stultz <john.stultz@linaro.org>
Date:   Fri, 5 Feb 2021 12:57:38 -0800
Message-ID: <CALAqxLXfK0eYGXDqsyfvMUzu6dxOb56WOe07ZsTayi3j1bT51g@mail.gmail.com>
Subject: Re: [RFC][PATCH v6 0/7] Generic page pool & deferred freeing for
 system dmabuf heap
To:     =?UTF-8?Q?Christian_K=C3=B6nig?= <christian.koenig@amd.com>
Cc:     lkml <linux-kernel@vger.kernel.org>,
        Daniel Vetter <daniel@ffwll.ch>,
        Sumit Semwal <sumit.semwal@linaro.org>,
        Liam Mark <lmark@codeaurora.org>,
        Chris Goldsworthy <cgoldswo@codeaurora.org>,
        Laura Abbott <labbott@kernel.org>,
        Brian Starkey <Brian.Starkey@arm.com>,
        Hridya Valsaraju <hridya@google.com>,
        Suren Baghdasaryan <surenb@google.com>,
        Sandeep Patil <sspatil@google.com>,
        Daniel Mentz <danielmentz@google.com>,
        =?UTF-8?Q?=C3=98rjan_Eide?= <orjan.eide@arm.com>,
        Robin Murphy <robin.murphy@arm.com>,
        Ezequiel Garcia <ezequiel@collabora.com>,
        Simon Ser <contact@emersion.fr>,
        James Jones <jajones@nvidia.com>,
        linux-media <linux-media@vger.kernel.org>,
        dri-devel <dri-devel@lists.freedesktop.org>
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On Fri, Feb 5, 2021 at 2:36 AM Christian K=C3=B6nig <christian.koenig@amd.c=
om> wrote:
> Am 05.02.21 um 09:06 schrieb John Stultz:
> > Input would be greatly appreciated. Testing as well, as I don't
> > have any development hardware that utilizes the ttm pool.
>
> We can easily do the testing and the general idea sounds solid to me.
>

Thanks so much again for the feedback!

> I see three major things we need to clean up here.
> 1. The licensing, you are moving from BSD/MIT to GPL2.

Yea, this may be sticky, as it's not just code re-used from one dual
licensed file, but combination of GPL2 work, so advice here would be
appreciated.

> 2. Don't add any new overhead to the TTM pool, especially allocating a
> private object per page is a no-go.

This will need some more series rework to solve. I've got some ideas,
but we'll see if they work.

> 3. What are you doing with the reclaim stuff and why?

As I mentioned, it's a holdover from earlier code, and I'm happy to
drop it and defer to other accounting/stats discussions that are
ongoing.

> 4. Keeping the documentation would be nice to have.

True. I didn't spend much time with documentation, as I worried folks
may have disagreed with the whole approach. I'll work to improve it
for the next go around.

Thanks so much again for the review and feedback! I really appreciate
your time here.
-john