From: Peter Zijlstra <peterz@infradead.org>
To: Michal Hocko <mhocko@suse.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Frederic Weisbecker <fweisbecker@suse.de>,
LKML <linux-kernel@vger.kernel.org>, Mel Gorman <mgorman@suse.de>,
Ingo Molnar <mingo@redhat.com>,
Richard Henderson <rth@twiddle.net>,
Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
Matt Turner <mattst88@gmail.com>,
linux-alpha@vger.kernel.org, Brian Cain <bcain@codeaurora.org>,
linux-hexagon@vger.kernel.org,
Geert Uytterhoeven <geert@linux-m68k.org>,
linux-m68k@lists.linux-m68k.org, Jeff Dike <jdike@addtoit.com>,
Richard Weinberger <richard@nod.at>,
Anton Ivanov <anton.ivanov@cambridgegreys.com>,
linux-um@lists.infradead.org
Subject: Re: [RFC PATCH] kernel: allow to configure PREEMPT_NONE, PREEMPT_VOLUNTARY on kernel command line
Date: Fri, 9 Oct 2020 13:42:16 +0200 [thread overview]
Message-ID: <20201009114216.GM2628@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20201009103730.GJ4967@dhcp22.suse.cz>
On Fri, Oct 09, 2020 at 12:37:30PM +0200, Michal Hocko wrote:
> On Fri 09-10-20 12:14:31, Peter Zijlstra wrote:
> > On Fri, Oct 09, 2020 at 12:10:44PM +0200, Michal Hocko wrote:
> > > On Fri 09-10-20 11:42:45, Peter Zijlstra wrote:
> > > > On Fri, Oct 09, 2020 at 11:12:18AM +0200, Michal Hocko wrote:
> > > > > Is there any additional feedback? Should I split up the patch and repost
> > > > > for inclusion?
> > > >
> > > > Maybe remove PREEMPT_NONE after that? Since that's then equivalent to
> > > > building with VOLUNTARY and booting with preempt=none.
> > >
> > > So do you mean that I should post an additional patch which does this on
> > > top? With a justification that there is one option less to chose from?
> >
> > Exactly!
>
> It seems we have to get rid of CONFIG_NO_PREEMPT first
> $ git grep ARCH_NO_PREEMPT
> arch/Kconfig:config ARCH_NO_PREEMPT
> arch/alpha/Kconfig: select ARCH_NO_PREEMPT
> arch/hexagon/Kconfig: select ARCH_NO_PREEMPT
> arch/m68k/Kconfig: select ARCH_NO_PREEMPT if !COLDFIRE
> arch/um/Kconfig: select ARCH_NO_PREEMPT
> kernel/Kconfig.preempt: depends on !ARCH_NO_PREEMPT
> kernel/Kconfig.preempt: depends on !ARCH_NO_PREEMPT
> lib/Kconfig.debug: select PREEMPT_COUNT if !ARCH_NO_PREEMPT
> lib/Kconfig.debug: depends on !ARCH_NO_PREEMPT
>
> Is there anybody working on that. Is this even possible? I can see it
> has been added by 87a4c375995e ("kconfig: include kernel/Kconfig.preempt
> from init/Kconfig") but this looks more like a mechanical change and it
> has defined ARCH_NO_PREEMPT all arches which haven't included
> Kconfig.preempt. But is there any reason why those cannot support
> preemption for some reason? Cc respective maintainer (the email thread
> starts http://lkml.kernel.org/r/20201007120401.11200-1-mhocko@kernel.org
I suspect we can drop ARCH_NO_PREEMPT from VOLUNTARY, IIRC there's no
arch dependency there. PREEMPT itself obviously needs arch help.
next prev parent reply other threads:[~2020-10-09 11:42 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-07 12:04 Michal Hocko
2020-10-07 12:19 ` Peter Zijlstra
2020-10-07 12:29 ` Michal Hocko
2020-10-07 13:01 ` Mel Gorman
2020-10-07 12:21 ` Peter Zijlstra
2020-10-07 12:35 ` Michal Hocko
2020-10-09 9:47 ` Peter Zijlstra
2020-10-09 10:14 ` Michal Hocko
2020-10-09 10:20 ` Peter Zijlstra
2020-10-09 10:48 ` Michal Hocko
2020-10-09 11:17 ` Michal Hocko
2020-10-09 11:26 ` Michal Hocko
2020-10-09 11:39 ` Peter Zijlstra
2020-10-09 9:12 ` Michal Hocko
2020-10-09 9:42 ` Peter Zijlstra
2020-10-09 10:10 ` Michal Hocko
2020-10-09 10:14 ` Peter Zijlstra
2020-10-09 10:37 ` Michal Hocko
2020-10-09 11:42 ` Peter Zijlstra [this message]
2020-10-09 12:29 ` [RFC PATCH v2 0/5] allow overriding default preempt mode from " Michal Hocko
2020-10-09 12:29 ` [RFC PATCH v2 1/5] jump_label: split out declaration parts into its own headers Michal Hocko
2020-10-09 12:29 ` [RFC PATCH v2 2/5] kernel: allow to configure PREEMPT_NONE, PREEMPT_VOLUNTARY on kernel command line Michal Hocko
2020-10-09 12:29 ` [RFC PATCH v2 3/5] kernel: ARCH_NO_PREEMPT shouldn't exclude PREEMPT_VOLUNTARY Michal Hocko
2020-10-09 12:29 ` [RFC PATCH v2 4/5] kernel: introduce CONFIG_PREEMPT_DYNAMIC Michal Hocko
2020-10-09 12:29 ` [RFC PATCH v2 5/5] kernel: drop PREEMPT_NONE compile time option Michal Hocko
2020-10-09 12:50 ` [RFC PATCH v2 0/5] allow overriding default preempt mode from command line Peter Zijlstra
2020-10-09 13:03 ` Michal Hocko
2020-10-09 13:22 ` Peter Zijlstra
2020-10-09 17:45 ` Peter Zijlstra
2020-10-27 12:22 ` Frederic Weisbecker
2020-10-27 12:28 ` Peter Zijlstra
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