cache: move open to thread pool

[Maxim Konovalov]

Hi Ka-Hing,

Roman told me that the delta is because of your changes.

Thanks for your time on that.  Waiting for your testing results.

Maxim

On 22/01/2019 22:34, Ka-Hing Cheung via nginx-devel wrote:
> I spoke too soon, just realized our test colo is running the patches
> without aio_open on. Flipping that switch now.
> 
> Also, including the patch that we applied on top in addition to the
> massaging we did to resolve conflicts. I haven't dug too deep to see
> if stock nginx also requires similar changes or they are only
> necessary because of our other nginx changes:
> 
[...]

-- 
Maxim Konovalov