linux-kernel - Re: [PATCH] sched/fair: enqueue_task

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20200512101805.GB31725@codeaurora.org>
Date:   Tue, 12 May 2020 15:48:05 +0530
From:   Pavan Kondeti <pkondeti@...eaurora.org>
To:     Vincent Guittot <vincent.guittot@...aro.org>
Cc:     mingo@...hat.com, peterz@...radead.org, juri.lelli@...hat.com,
        dietmar.eggemann@....com, rostedt@...dmis.org, bsegall@...gle.com,
        mgorman@...e.de, linux-kernel@...r.kernel.org, pauld@...hat.com,
        ouwen210@...mail.com
Subject: Re: [PATCH] sched/fair: enqueue_task_fair optimization

On Mon, May 11, 2020 at 09:23:01PM +0200, Vincent Guittot wrote:
> enqueue_task_fair() jumps to enqueue_throttle when cfs_rq_of(se) is
> throttled, which means that se can't be NULL and we can skip the test.
> 
> Signed-off-by: Vincent Guittot <vincent.guittot@...aro.org>
> ---
>  kernel/sched/fair.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 4b73518aa25c..910bbbe50365 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -5512,7 +5512,6 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
>                         list_add_leaf_cfs_rq(cfs_rq);
>  	}
>  
> -enqueue_throttle:
>  	if (!se) {
>  		add_nr_running(rq, 1);
>  		/*
> @@ -5534,6 +5533,7 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
>  
>  	}
>  
> +enqueue_throttle:
>  	if (cfs_bandwidth_used()) {
>  		/*
>  		 * When bandwidth control is enabled; the cfs_rq_throttled()

Right, se can't be NULL when we break upon throttling. Looks good to me.

Thanks,
Pavan

-- 
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.