From: Valentin Schneider <valentin.schneider@arm.com>
To: Mike Galbraith <efault@gmx.de>, linux-kernel@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Frederic Weisbecker <frederic@kernel.org>
Subject: Re: [PATCH] sched: Tweak default dynamic preempt mode selection
Date: Mon, 08 Nov 2021 11:17:38 +0000 [thread overview]
Message-ID: <8735o6uca5.mognet@arm.com> (raw)
In-Reply-To: <ff53a94401f8d6abe0303ee381f86bfb475ad354.camel@gmx.de>
On 06/11/21 05:40, Mike Galbraith wrote:
> On Fri, 2021-11-05 at 10:40 +0000, Valentin Schneider wrote:
>> Commit c597bfddc9e9 ("sched: Provide Kconfig support for default dynamic
>> preempt mode") changed the selectable config names for the preemption
>> model. This means a config file must now select
>>
>> CONFIG_PREEMPT_BEHAVIOUR=y
>>
>> rather than
>>
>> CONFIG_PREEMPT=y
>>
>> to get a preemptible kernel. This means all arch config files need to be
>> updated - right now arm64 defconfig selects CONFIG_PREEMPT=y but ends up
>> with CONFIG_PREEMPT_NONE_BEHAVIOUR=y.
>>
>> Instead, have CONFIG_*PREEMPT be the selectable configs again, and make
>> them select their _BEHAVIOUR equivalent if CONFIG_PREEMPT_DYNAMIC is set.
>
>
> Is there any way to get to PREEMPT_RT in the first selection again as
> well? I had created a behavior entry for RT (below) and inverted the
> dependency to make it appear in the initial selection again, but that's
> clearly not gonna fly.
>
> Starting with a 5.15 config, to select RT you currently must first
> select a model you don't want, then reject PREEMPT_DYNAMIC and you'll
> be offered the full menu of models immediately. With your patch added,
> that became worse. After rejecting PREEMPT_DYNAMIC, I had to go
> through new 5.15+ options before finally being offered the full menu.
>
Do you mean at the syncconfig step? I've only really played with upstream
arm64 / x86 defconfigs and didn't have to fight with any prompts, though
yes for x86 the default-y PREEMPT_DYNAMIC makes it a bit annoying to select
PREEMPT_RT.
next prev parent reply other threads:[~2021-11-08 11:17 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-05 10:40 [PATCH] sched: Tweak default dynamic preempt mode selection Valentin Schneider
2021-11-06 4:40 ` Mike Galbraith
2021-11-08 11:17 ` Valentin Schneider [this message]
2021-11-08 12:27 ` Mike Galbraith
2021-11-08 15:21 ` Valentin Schneider
2021-11-09 5:30 ` Mike Galbraith
2021-11-09 9:52 ` Valentin Schneider
2021-11-09 11:00 ` Mike Galbraith
2021-11-09 12:19 ` Valentin Schneider
2021-11-09 13:31 ` Mike Galbraith
2021-11-06 5:05 ` kernel test robot
2021-11-06 5:05 ` kernel test robot
2021-11-08 12:00 ` Valentin Schneider
2021-11-08 12:00 ` Valentin Schneider
2021-11-06 5:33 ` kernel test robot
2021-11-06 5:33 ` kernel test robot
2021-11-06 7:58 ` kernel test robot
2021-11-06 7:58 ` kernel test robot
2021-11-09 10:25 ` Frederic Weisbecker
2021-11-10 0:03 ` Valentin Schneider
2021-11-10 5:44 ` Mike Galbraith
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=8735o6uca5.mognet@arm.com \
--to=valentin.schneider@arm.com \
--cc=efault@gmx.de \
--cc=frederic@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=peterz@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.