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From: Michal Hocko <mhocko@suse.com>
To: Peter Zijlstra <peterz@infradead.org>
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>
Subject: Re: [RFC PATCH] kernel: allow to configure PREEMPT_NONE, PREEMPT_VOLUNTARY on kernel command line
Date: Wed, 7 Oct 2020 14:35:53 +0200	[thread overview]
Message-ID: <20201007123553.GK29020@dhcp22.suse.cz> (raw)
In-Reply-To: <20201007122144.GF2628@hirez.programming.kicks-ass.net>

On Wed 07-10-20 14:21:44, Peter Zijlstra wrote:
> On Wed, Oct 07, 2020 at 02:04:01PM +0200, Michal Hocko wrote:
> > I wanted to make sure that the idea is sound for maintainers first. The
> > next step would be extending the command line to support full preemption
> > as well but there is much more work in that area. Frederic has promissed
> > to look into that.
> 
> The sanest way there is to static_call() __preempt_schedule() I think.

Yes, I have checked the code and identified few other places like
irqentry_exit_cond_resched. We also need unconditional
CONFIG_PREEMPT_COUNT IIUC and there are quite some places guarded by
CONFIG_PREEMPTION that would need to be examined. Some of them are
likely pretending to be more clever than they really are/should be -
e.g. mm/slub.c. So there is likely a lot of leg work.
-- 
Michal Hocko
SUSE Labs

  reply	other threads:[~2020-10-07 12:35 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-07 12:04 [RFC PATCH] kernel: allow to configure PREEMPT_NONE, PREEMPT_VOLUNTARY on kernel command line 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 [this message]
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
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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