From: Jens Axboe <axboe@kernel.dk>
To: Pavel Begunkov <asml.silence@gmail.com>,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/2][for-next] cleanup submission path
Date: Sun, 27 Oct 2019 10:56:46 -0600 [thread overview]
Message-ID: <d39a878f-9dac-1457-6bba-01afc6268a84@kernel.dk> (raw)
In-Reply-To: <aac65fe2-6c51-3baf-eee7-af5a8f633bf2@kernel.dk>
On 10/27/19 10:49 AM, Jens Axboe wrote:
> On 10/27/19 10:44 AM, Pavel Begunkov wrote:
>> On 27/10/2019 19:32, Jens Axboe wrote:
>>> On 10/27/19 9:35 AM, Pavel Begunkov wrote:
>>>> A small cleanup of very similar but diverged io_submit_sqes() and
>>>> io_ring_submit()
>>>>
>>>> Pavel Begunkov (2):
>>>> io_uring: handle mm_fault outside of submission
>>>> io_uring: merge io_submit_sqes and io_ring_submit
>>>>
>>>> fs/io_uring.c | 116 ++++++++++++++------------------------------------
>>>> 1 file changed, 33 insertions(+), 83 deletions(-)
>>>
>>> I like the cleanups here, but one thing that seems off is the
>>> assumption that io_sq_thread() always needs to grab the mm. If
>>> the sqes processed are just READ/WRITE_FIXED, then it never needs
>>> to grab the mm.
>>> Yeah, we removed it to fix bugs. Personally, I think it would be
>> clearer to do lazy grabbing conditionally, rather than have two
>> functions. And in this case it's easier to do after merging.
>>
>> Do you prefer to return it back first?
>
> Ah I see, no I don't care about that.
OK, looked at the post-patches state. It's still not correct. You are
grabbing the mm from io_sq_thread() unconditionally. We should not do
that, only if the sqes we need to submit need mm context.
--
Jens Axboe
next prev parent reply other threads:[~2019-10-27 16:56 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-27 15:35 [PATCH 0/2][for-next] cleanup submission path Pavel Begunkov
2019-10-27 15:35 ` [PATCH 1/2] io_uring: handle mm_fault outside of submission Pavel Begunkov
2019-10-27 15:35 ` [PATCH 2/2] io_uring: merge io_submit_sqes and io_ring_submit Pavel Begunkov
2019-10-27 16:32 ` [PATCH 0/2][for-next] cleanup submission path Jens Axboe
2019-10-27 16:44 ` Pavel Begunkov
2019-10-27 16:49 ` Jens Axboe
2019-10-27 16:56 ` Jens Axboe [this message]
2019-10-27 17:19 ` Pavel Begunkov
2019-10-27 17:26 ` Jens Axboe
2019-10-27 17:37 ` Pavel Begunkov
2019-10-27 18:56 ` Pavel Begunkov
2019-10-27 19:02 ` Jens Axboe
2019-10-27 19:17 ` Pavel Begunkov
2019-10-27 19:51 ` Jens Axboe
2019-10-27 19:59 ` Pavel Begunkov
2019-10-28 3:38 ` Jens Axboe
2019-10-28 11:12 ` Pavel Begunkov
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