[PATCH 1/3] dma-fence: Reserve 0 as a special NO_CONTEXT token

Chris Wilson chris at chris-wilson.co.uk
Sat Apr 8 18:00:34 UTC 2017

On Sat, Apr 08, 2017 at 07:49:37PM +0200, Christian K├Ânig wrote:
> Am 08.04.2017 um 18:26 schrieb Chris Wilson:
> >Reserve 0 for general use a token meaning that the fence doesn't belong
> >to an ordered timeline (fence context).
> NAK, we kept context allocation cheap to avoid exactly that.

However, they result in very sparse mappings.

> Please elaborate further why it should be necessary now.

Because I want to efficiently exclude them from comparisons as
demonstrated by this small series as there may be several hundred such
fences as dependencies for this job.

Chris Wilson, Intel Open Source Technology Centre

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