linux-kernel - Re: [patch 05/50] sched: Provide schedule point for RT locks

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Date:   Wed, 14 Jul 2021 10:28:20 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Juri Lelli <juri.lelli@...hat.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Daniel Bristot de Oliveira <bristot@...hat.com>,
        Will Deacon <will@...nel.org>,
        Waiman Long <longman@...hat.com>,
        Boqun Feng <boqun.feng@...il.com>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Davidlohr Bueso <dave@...olabs.net>
Subject: Re: [patch 05/50] sched: Provide schedule point for RT locks

On Tue, Jul 13, 2021 at 05:10:59PM +0200, Thomas Gleixner wrote:

> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -5832,8 +5832,14 @@ pick_next_task(struct rq *rq, struct tas
>   */
>  #define	SM_NONE			0x0
>  #define	SM_PREEMPT		0x1
> -#define SM_MASK_PREEMPT		UINT_MAX
> -#define SM_MASK_STATE		SM_MASK_PREEMPT
> +#ifndef CONFIG_PREEMPT_RT
> +# define SM_MASK_PREEMPT	UINT_MAX
> +# define SM_MASK_STATE		SM_MASK_PREEMPT
> +#else
> +# define SM_RTLOCK_WAIT		0x2
> +# define SM_MASK_PREEMPT	SM_PREEMPT
> +# define SM_MASK_STATE		(SM_PREEMPT | SM_RTLOCK_WAIT)
> +#endif

Wouldn't something like this:


#ifndef CONFIG_PREEMPT_RT
# define SM_MASK_PREEMPT        (~0U)
#else
# define SM_RTLOCK_WAIT         0x2
# define SM_MASK_PREEMPT        SM_PREEMPT
#endif

#define SM_MASK_STATE          (~0U)

Be even better?