Re: [PATCH 2/2] io_uring: switch cancel_hash to use per list spinlock

[Jens Axboe <axboe@kernel.dk>]

On 5/29/22 10:20 AM, Hao Xu wrote:
> From: Hao Xu <howeyxu@tencent.com>
> 
> From: Hao Xu <howeyxu@tencent.com>
> 
> Use per list lock for cancel_hash, this removes some completion lock
> invocation and remove contension between different cancel_hash entries

Interesting, do you have any numbers on this?

Also, I'd make a hash bucket struct:

struct io_hash_bucket {
	spinlock_t lock;
	struct hlist_head list;
};

rather than two separate structs, that'll have nicer memory locality too
and should further improve it. Could be done as a prep patch with the
old locking in place, making the end patch doing the per-bucket lock
simpler as well.

Hmm?

-- 
Jens Axboe