From: Gustavo Padovan <gustavo.padovan@collabora.com>
To: "Christian König" <deathsimple@vodafone.de>
Cc: "Gustavo Padovan" <gustavo@padovan.org>,
"Christian König" <christian.koenig@amd.com>,
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,
"Gustavo Padovan" <gustavo.padovan@collabora.co.uk>,
"John Harrison" <John.C.Harrison@Intel.com>,
m.chehab@samsung.com
Subject: Re: [RFC 0/5] rework fences on struct sync_file
Date: Fri, 24 Jun 2016 11:59:33 -0300 [thread overview]
Message-ID: <20160624145933.GF2508@joana> (raw)
In-Reply-To: <576D4032.3000001@vodafone.de>
2016-06-24 Christian König <deathsimple@vodafone.de>:
> Am 24.06.2016 um 15:17 schrieb Gustavo Padovan:
> > Hi Christian,
> >
> > 2016-06-24 Christian König <christian.koenig@amd.com>:
> >
> > > Am 23.06.2016 um 17:29 schrieb Gustavo Padovan:
> > > > From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
> > > >
> > > > Hi all,
> > > >
> > > > This is an attempt to improve fence support on Sync File. The basic idea
> > > > is to have only sync_file->fence and store all fences there, either as
> > > > normal fences or fence_arrays. That way we can remove some potential
> > > > duplication when using fence_array with sync_file: the duplication of the array
> > > > of fences and the duplication of fence_add_callback() for all fences.
> > > >
> > > > Now when creating a new sync_file during the merge process sync_file_set_fence()
> > > > will set sync_file->fence based on the number of fences for that sync_file. If
> > > > there is more than one fence a fence_array is created. One important advantage
> > > > approach is that we only add one fence callback now, no matter how many fences
> > > > there are in a sync_file - the individual callbacks are added by fence_array.
> > > >
> > > > Two fence ops had to be created to help abstract the difference between handling
> > > > fences and fences_arrays: .teardown() and .get_fences(). The former run needed
> > > > on fence_array, and the latter just return a copy of all fences in the fence.
> > > > I'm not so sure about adding those two, speacially .get_fences(). What do you
> > > > think?
> > > Clearly not a good idea to add this a fence ops, cause those are specialized
> > > functions for only a certain fence implementation (the fence_array).
> > Are you refering only to .get_fences()?
>
> That comment was only for the get_fences() operation, but the teardown()
> callback looks very suspicious to me as well.
>
> Can you explain once more why that should be necessary?
When the sync_file owner exits we need to clean up it and that means releasing
the fence too, however with fence_array we can't just call fence_put()
as a extra reference to array->base for each fence is held when enabling
signalling. Thus we need a prior step, that I called teardown(), to
remove the callback for not signaled fences and put the extra
references.
Another way to do this would be:
if (fence_is_array(sync_file->fence))
fence_array_destroy(to_fence_array(sync_file->fence));
else
fence_put(sync_file_fence);
This would avoid the extra ops, maybe we should go this way.
Gustavo
next prev parent reply other threads:[~2016-06-24 14:59 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-23 15:29 [RFC 0/5] rework fences on struct sync_file Gustavo Padovan
2016-06-23 15:29 ` [RFC 1/5] dma-buf/fence: add .teardown() ops Gustavo Padovan
2016-06-23 20:48 ` Chris Wilson
2016-06-24 13:19 ` Gustavo Padovan
2016-07-12 10:51 ` Daniel Vetter
2016-06-23 15:29 ` [RFC 2/5] dma-buf/fence-array: add fence_array_teardown() Gustavo Padovan
2016-06-23 15:29 ` [RFC 3/5] dma-buf/fence: add .get_fences() ops Gustavo Padovan
2016-06-23 20:40 ` Chris Wilson
2016-07-12 10:52 ` Daniel Vetter
2016-06-23 15:29 ` [RFC 4/5] dma-buf/fence-array: add fence_array_get_fences() Gustavo Padovan
2016-06-23 20:35 ` Chris Wilson
2016-06-23 15:29 ` [RFC 5/5] dma-buf/sync_file: rework fence storage in struct file Gustavo Padovan
2016-06-23 21:27 ` Chris Wilson
2016-06-24 13:23 ` Gustavo Padovan
2016-06-24 9:27 ` [RFC 0/5] rework fences on struct sync_file Christian König
2016-06-24 13:17 ` Gustavo Padovan
2016-06-24 14:14 ` Christian König
2016-06-24 14:59 ` Gustavo Padovan [this message]
2016-06-24 15:09 ` Christian König
2016-06-24 15:19 ` Gustavo Padovan
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