On 8/26/19 11:23 AM, Hristo Venev wrote:
> Both the sq and the cq rings have sizes just over a power of two, and
> the sq ring is significantly smaller. By bundling them in a single
> alllocation, we get the sq ring for free.
> 
> This also means that IORING_OFF_SQ_RING and IORING_OFF_CQ_RING now mean
> the same thing. If we indicate this to userspace, we can save a mmap
> call.

This looks pretty good to me. My only worry was ending up with sq and
cq cacheline sharing, but the alignment of the io_uring struct itself
should prevent that nicely.

Outside of going for a cleanup, have you observed any wins from this
change?

-- 
Jens Axboe

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