linux-kernel - Re: [PATCH 1/1] sched: preempt: Move dynamic keys into kernel/sched

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Message-ID: <aHEmJvhUVG_x1FZx@willie-the-truck>
Date: Fri, 11 Jul 2025 15:56:38 +0100
From: Will Deacon <will@...nel.org>
To: Shrikanth Hegde <sshegde@...ux.ibm.com>
Cc: mingo@...hat.com, peterz@...radead.org, juri.lelli@...hat.com,
	vincent.guittot@...aro.org, maddy@...ux.ibm.com, tglx@...utronix.de,
	bigeasy@...utronix.de, vschneid@...hat.com,
	dietmar.eggemann@....com, rostedt@...dmis.org,
	linux-kernel@...r.kernel.org, catalin.marinas@....com,
	linux-arm-kernel@...ts.infradead.org, mark.rutland@....com
Subject: Re: [PATCH 1/1] sched: preempt: Move dynamic keys into kernel/sched

On Tue, Jun 10, 2025 at 01:23:44PM +0530, Shrikanth Hegde wrote:
> Dynamic preemption can be static key or static call based.
> Static key is used to check kernel preemption depending on
> the current preemption model. i.e enable for lazy, full. 
> 
> Code is spread currently across entry/common.c, arm64 and latest being
> powerpc. There is little arch specific to it. For example, arm64,
> powerpc does the same thing. It is better to move it into kernel/sched 
> since preemption is more closely associated with scheduler.  
> 
> Plus, Any new arch that wants dynamic preemption enabled need to have 
> only HAVE_PREEMPT_DYNAMIC_KEY. 
> 
> This is more of code movement. No functional change. 
> 
> Suggested-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
> Signed-off-by: Shrikanth Hegde <sshegde@...ux.ibm.com>
> ---
>  arch/arm64/include/asm/preempt.h   |  1 -
>  arch/arm64/kernel/entry-common.c   |  8 --------
>  arch/powerpc/include/asm/preempt.h | 16 ----------------
>  arch/powerpc/kernel/interrupt.c    |  4 ----
>  include/linux/entry-common.h       |  1 -
>  include/linux/sched.h              |  8 ++++++++
>  kernel/entry/common.c              |  1 -
>  kernel/sched/core.c                |  4 ++++
>  8 files changed, 12 insertions(+), 31 deletions(-)
>  delete mode 100644 arch/powerpc/include/asm/preempt.h

Acked-by: Will Deacon <will@...nel.org>

Will