Re: [PATCH for-next v3 00/16] 5.20 cleanups and poll optimisations

[Hao Xu <hao.xu@linux.dev>]

On 6/16/22 17:21, Pavel Begunkov wrote:
> 1-4 kills REQ_F_COMPLETE_INLINE as we're out of bits.
> 
> Patch 5 from Hao should remove some overhead from poll requests
> 
> Patch 6 from Hao adds per-bucket spinlocks, and 16-19 do a little
> bit of cleanup. The downside of per-bucket spinlocks is that it adds
> additional spinlock/unlock pair in the poll request completion side,
> which shouldn't matter much with 20/25.
> 
> Patch 11 uses inline completion infra for poll requests, this nicely
> improves perf when there is a good tw batching.
> 
> Patch 12 implements the userspace visible side of
> IORING_SETUP_SINGLE_ISSUER, it'll be used for poll requests and
> later for spinlock optimisations.
> 
> 13-16 introduces ->uring_lock protected cancellation hashing. It
> requires us to grab ->uring_lock in the completion side, but saves
> two spin lock/unlock pairs. We apply it automatically in cases the
> mutex is already likely to be held (see 25/25 description), so there
> is no additional mutex overhead and potential latency problemes.
> 

Reviewed-by: Hao Xu <howeyxu@tencent.com>