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

[Andres Rodriguez <andresx7@gmail.com>]

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@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.

-Andres

> Christian.
>
>>
>> Dave.
>
>