linux-kernel - Re: [PATCH 09/23] sched,ivtv: Convert to sched_set

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: <20200422085345.48b50508@gandalf.local.home>
Date:   Wed, 22 Apr 2020 08:53:45 -0400
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     mingo@...nel.org, linux-kernel@...r.kernel.org, tglx@...utronix.de,
        qais.yousef@....com, juri.lelli@...hat.com,
        vincent.guittot@...aro.org, dietmar.eggemann@....com,
        bsegall@...gle.com, mgorman@...e.de, hverkuil@...all.nl,
        awalls@...metrocast.net
Subject: Re: [PATCH 09/23] sched,ivtv: Convert to sched_set_fifo*()

On Wed, 22 Apr 2020 13:27:28 +0200
Peter Zijlstra <peterz@...radead.org> wrote:

> Because SCHED_FIFO is a broken scheduler model (see previous patches)
> take away the priority field, the kernel can't possibly make an
> informed decision.
> 
> Effectively changes from 99 to 50.

I wonder for the 99 users, we should have a sched_set_high() that would set
the task to something like 75.

That is, above default 50?


-- Steve


> 
> Cc: hverkuil@...all.nl
> Cc: awalls@...metrocast.net
> Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
> Reviewed-by: Ingo Molnar <mingo@...nel.org>
> ---
>  drivers/media/pci/ivtv/ivtv-driver.c |    4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> --- a/drivers/media/pci/ivtv/ivtv-driver.c
> +++ b/drivers/media/pci/ivtv/ivtv-driver.c
> @@ -737,8 +737,6 @@ static void ivtv_process_options(struct
>   */
>  static int ivtv_init_struct1(struct ivtv *itv)
>  {
> -	struct sched_param param = { .sched_priority = 99 };
> -
>  	itv->base_addr = pci_resource_start(itv->pdev, 0);
>  	itv->enc_mbox.max_mbox = 2; /* the encoder has 3 mailboxes (0-2) */
>  	itv->dec_mbox.max_mbox = 1; /* the decoder has 2 mailboxes (0-1) */
> @@ -758,7 +756,7 @@ static int ivtv_init_struct1(struct ivtv
>  		return -1;
>  	}
>  	/* must use the FIFO scheduler as it is realtime sensitive */
> -	sched_setscheduler(itv->irq_worker_task, SCHED_FIFO, &param);
> +	sched_set_fifo(itv->irq_worker_task);
>  
>  	kthread_init_work(&itv->irq_work, ivtv_irq_work_handler);
>  
>