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From:   Justin Forbes <jforbes@redhat.com>
Date:   Thu, 27 May 2021 11:01:13 -0500
Message-ID: <CAFbkSA2zt5QLBH0S8pcBROCaV3zSw_M-RvaQ-2yccCKgV-_2BQ@mail.gmail.com>
Subject: Re: [PATCH] io_uring: Remove CONFIG_EXPERT
To:     Jens Axboe <axboe@kernel.dk>
Cc:     asml.silence@gmail.com, io-uring@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Thu, May 27, 2021 at 9:19 AM Jens Axboe <axboe@kernel.dk> wrote:
>
> On 5/27/21 8:12 AM, Justin Forbes wrote:
> > On Thu, May 27, 2021 at 8:43 AM Jens Axboe <axboe@kernel.dk> wrote:
> >>
> >> On 5/26/21 4:34 PM, Justin M. Forbes wrote:
> >>> While IO_URING has been in fairly heavy development, it is hidden behind
> >>> CONFIG_EXPERT with a default of on.  It has been long enough now that I
> >>> think we should remove EXPERT and allow users and distros to decide how
> >>> they want this config option set without jumping through hoops.
> >>
> >> The whole point of EXPERT is to ensure that it doesn't get turned off
> >> "by accident". It's a core feature, and something that more and more
> >> apps or libraries are relying on. It's not something I intended to ever
> >> go away, just like it would never go away for eg futex or epoll support.
> >>
> >
> > I am not arguing with that, I don't expect it will go away. I
> > certainly do not have an issue with it defaulting to on, and I didn't
> > even submit this with intention to turn it off for default Fedora. I
> > do think that there are cases where people might not wish it turned on
> > at this point in time. Hiding it behind EXPERT makes it much more
> > difficult than it needs to be.  There are plenty of config options
> > that are largely expected default and not hidden behind EXPERT.
>
> Right there are, but not really core kernel features like the ones
> I mentioned. Hence my argument for why it's correct as-is and I
> don't think it should be changed.
>

Honestly, this is fair, and I understand your concerns behind it. I
think my real issue is that there is no simple way to override one
EXPERT setting without having to set them all.  It would be nice if
expert were a "visible if" menu, setting defaults if not selected,
which allows direct override with a config file. Perhaps I will try to
fix this in kbuild.

Justin