[PATCH] dma-buf: avoid scheduling on fence status query

Andres Rodriguez andresx7 at gmail.com
Wed Apr 26 14:28:49 UTC 2017

On 2017-04-26 06:13 AM, Christian König wrote:
> Am 26.04.2017 um 11:59 schrieb Dave Airlie:
>> On 26 April 2017 at 17:20, Christian König <deathsimple at vodafone.de>
>> wrote:
>>> NAK, I'm wondering how often I have to reject that change. We should
>>> probably add a comment here.
>>> Even with a zero timeout we still need to enable signaling, otherwise
>>> some
>>> fence will never signal if userspace just polls on them.
>>> If a caller is only interested in the fence status without enabling the
>>> signaling it should call dma_fence_is_signaled() instead.
>> Can we not move the return 0 (with spin unlock) down after we enabling
>> signalling, but before
>> we enter the schedule_timeout(1)?
> Yes, that would be an option.

I was actually arguing with Dave about this on IRC yesterday. Seems like 
I owe him a beer now.


> Christian.
>> Dave.

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