From mboxrd@z Thu Jan  1 00:00:00 1970
From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Subject: Re: [PATCH 1/2] dma-buf/fence: add fence_collection fences
Date: Thu, 19 May 2016 10:20:07 -0300
Message-ID: <20160519132007.GA15155@joana>
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To: Christian =?iso-8859-1?Q?K=F6nig?= <christian.koenig@amd.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>, Gustavo Padovan <gustavo@padovan.org>, dri-devel@lists.freedesktop.org, marcheu@google.com, Daniel Stone <daniels@collabora.com>, seanpaul@google.com, Daniel Vetter <daniel.vetter@ffwll.ch>, linux-kernel@vger.kernel.org, laurent.pinchart@ideasonboard.com, Alex Deucher <alexander.deucher@amd.com>, John Harrison <John.C.Harrison@Intel.com>, m.chehab@samsung.com
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Hi Christian,

2016-05-19 Christian K=F6nig <christian.koenig@amd.com>:

> Am 19.05.2016 um 00:57 schrieb Chris Wilson:
> > On Wed, May 18, 2016 at 05:59:52PM -0300, Gustavo Padovan wrote:
> > > +static void collection_check_cb_func(struct fence *fence, struct=
 fence_cb *cb)
> > > +{
> > > +	struct fence_collection_cb *f_cb;
> > > +	struct fence_collection *collection;
> > > +
> > > +	f_cb =3D container_of(cb, struct fence_collection_cb, cb);
> > > +	collection =3D f_cb->collection;
> > > +
> > > +	if (atomic_dec_and_test(&collection->num_pending_fences))
> > > +		fence_signal(&collection->base);
> > > +}
> > > +
> > > +static bool fence_collection_enable_signaling(struct fence *fenc=
e)
> > > +{
> > > +	struct fence_collection *collection =3D to_fence_collection(fen=
ce);
> > > +	int i;
> > > +
> > > +	for (i =3D 0 ; i < collection->num_fences ; i++) {
> > > +		if (fence_add_callback(collection->fences[i].fence,
> > > +				       &collection->fences[i].cb,
> > > +				       collection_check_cb_func)) {
> > > +			atomic_dec(&collection->num_pending_fences);
> > > +		}
> > > +	}
> > We don't always have a convenient means to preallocate an array of
> > fences to use. Keeping a list of fences in addition to the array wo=
uld
> > be easier to user in many circumstances.
>=20
> I agree that there is use for such an implementation as well, but as
> mentioned in the last review cycle we intentionally chose an array in=
stead
> of a more complex implementation here.
>=20
> This way the array can be passed to function like fence_wait_any_time=
out()
> as well.
>=20
> I also suggested to rename it to fence_array to make that difference =
clear
> and allow for another implementation to live side by side with this.
>=20
> My crux at the moment is that I need both for the amdgpu driver, an a=
rray
> based implementation and a collection like one.
>=20
> Gustavo would you mind if I take your patches and work a bit on this?

Please go ahead with this and let me know if you need anything from me.

	Gustavo