linux-kernel - Re: [PATCH v2] sched/fair: don't push cfs

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Message-ID: <20190611135325.GY3436@hirez.programming.kicks-ass.net>
Date:   Tue, 11 Jun 2019 15:53:25 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     bsegall@...gle.com
Cc:     linux-kernel@...r.kernel.org,
        Xunlei Pang <xlpang@...ux.alibaba.com>,
        Ingo Molnar <mingo@...hat.com>, Phil Auld <pauld@...hat.com>
Subject: Re: [PATCH v2] sched/fair: don't push cfs_bandwith slack timers
 forward

On Thu, Jun 06, 2019 at 10:21:01AM -0700, bsegall@...gle.com wrote:
> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
> index efa686eeff26..60219acda94b 100644
> --- a/kernel/sched/sched.h
> +++ b/kernel/sched/sched.h
> @@ -356,6 +356,7 @@ struct cfs_bandwidth {
>  	u64			throttled_time;
>  
>  	bool                    distribute_running;
> +	bool                    slack_started;
>  #endif
>  };

I'm thinking we can this instead? afaict both idle and period_active are
already effecitively booleans and don't need the full 16 bits.

--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -338,8 +338,10 @@ struct cfs_bandwidth {
 	u64			runtime_expires;
 	int			expires_seq;
 
-	short			idle;
-	short			period_active;
+	u8			idle;
+	u8			period_active;
+	u8			distribute_running;
+	u8			slack_started;
 	struct hrtimer		period_timer;
 	struct hrtimer		slack_timer;
 	struct list_head	throttled_cfs_rq;
@@ -348,9 +350,6 @@ struct cfs_bandwidth {
 	int			nr_periods;
 	int			nr_throttled;
 	u64			throttled_time;
-
-	bool                    distribute_running;
-	bool                    slack_started;
 #endif
 };