From: Jens Axboe <[email protected]>
To: Xiaoguang Wang <[email protected]>,
[email protected]
Subject: Re: [PATCH 8/8] io_uring: enable IORING_SETUP_ATTACH_WQ to attach to SQPOLL thread too
Date: Mon, 7 Sep 2020 10:14:27 -0600 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
On 9/7/20 2:56 AM, Xiaoguang Wang wrote:
> 3. When it's appropriate to set ctx's IORING_SQ_NEED_WAKEUP flag? In
> your current implementation, if a ctx is marked as SQT_IDLE, this ctx
> will be set IORING_SQ_NEED_WAKEUP flag, but if other ctxes have work
> to do, then io_sq_thread is still running and does not need to be
> waken up, then a later wakeup form userspace is unnecessary. I think
> it maybe appropriate to set IORING_SQ_NEED_WAKEUP when all ctxes have
> no work to do, you can have a look at my attached codes:)
That's a good point, any chance I can get you to submit a patch to fix
that up?
> 4. Is io_attach_sq_data really safe? sqd_list is a global list, but
> its search key is a fd local to process, different processes may have
> same fd, then this codes looks odd, seems that your design is to make
> io_sq_thread shared inside process.
It's really meant for thread sharing, or you could pass the fd and use
it across a process too. See the incremental I just sent in a reply to
Pavel.
That said, I do think the per-cpu approach has merrit, and I also think
it should be possible to layer it on top of the existing code in
for-5.10/io_uring. So I'd strongly encourage you to try and do that, so
you can get rid of using that private patch and just have it upstream
instead.
--
Jens Axboe
next prev parent reply other threads:[~2020-09-07 16:17 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-03 2:20 [PATCHSET for-next 0/8] io_uring SQPOLL improvements Jens Axboe
2020-09-03 2:20 ` [PATCH 1/8] io_uring: io_sq_thread() doesn't need to flush signals Jens Axboe
2020-09-03 2:20 ` [PATCH 2/8] io_uring: allow SQPOLL with CAP_SYS_NICE privileges Jens Axboe
2020-09-03 2:20 ` [PATCH 3/8] io_uring: use private ctx wait queue entries for SQPOLL Jens Axboe
2020-09-03 2:20 ` [PATCH 4/8] io_uring: move SQPOLL post-wakeup ring need wakeup flag into wake handler Jens Axboe
2020-09-03 2:20 ` [PATCH 5/8] io_uring: split work handling part of SQPOLL into helper Jens Axboe
2020-09-03 2:20 ` [PATCH 6/8] io_uring: split SQPOLL data into separate structure Jens Axboe
2020-09-03 2:20 ` [PATCH 7/8] io_uring: base SQPOLL handling off io_sq_data Jens Axboe
2020-09-03 2:20 ` [PATCH 8/8] io_uring: enable IORING_SETUP_ATTACH_WQ to attach to SQPOLL thread too Jens Axboe
2020-09-07 8:56 ` Xiaoguang Wang
2020-09-07 14:00 ` Pavel Begunkov
2020-09-07 16:11 ` Jens Axboe
2020-09-07 16:14 ` Jens Axboe [this message]
2020-09-07 16:18 ` Jens Axboe
2020-09-08 2:28 ` Xiaoguang Wang
2020-09-08 2:53 ` Xiaoguang Wang
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