linux-kernel - Re: [PATCH v2 4/9] sched/topology: Kill SD_LOAD

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Message-ID: <a4a87ce6-9770-dc58-c2b6-e001b8050a8e@arm.com>
Date:   Thu, 19 Mar 2020 11:29:25 +0100
From:   Dietmar Eggemann <dietmar.eggemann@....com>
To:     Valentin Schneider <valentin.schneider@....com>,
        linux-kernel@...r.kernel.org
Cc:     mingo@...nel.org, peterz@...radead.org, vincent.guittot@...aro.org
Subject: Re: [PATCH v2 4/9] sched/topology: Kill SD_LOAD_BALANCE

On 11.03.20 19:15, Valentin Schneider wrote:
> That flag is set unconditionally in sd_init(), and no one checks for it
> anymore. Remove it.

Why not merge 3/9 and 4/9 ?

[...]

> diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h
> index f341163fedc9..8de2f9744569 100644
> --- a/include/linux/sched/topology.h
> +++ b/include/linux/sched/topology.h
> @@ -11,21 +11,20 @@
>   */
>  #ifdef CONFIG_SMP
>  
> -#define SD_LOAD_BALANCE		0x0001	/* Do load balancing on this domain. */
> -#define SD_BALANCE_NEWIDLE	0x0002	/* Balance when about to become idle */

[...]

> -#define SD_OVERLAP		0x2000	/* sched_domains of this level overlap */
> -#define SD_NUMA			0x4000	/* cross-node balancing */
> +#define SD_BALANCE_NEWIDLE	0x0001	/* Balance when about to become idle */

IMHO, changing the values of the remaining SD flags will break lots of
userspace scripts.

[...]