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From: Pavan Kondeti <pkondeti@codeaurora.org>
To: Parth Shah <parth@linux.ibm.com>
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org,
	mingo@redhat.com, vincent.guittot@linaro.org,
	dietmar.eggemann@arm.com, qais.yousef@arm.com,
	chris.hyser@oracle.com, patrick.bellasi@matbug.net,
	valentin.schneider@arm.com, David.Laight@ACULAB.COM,
	pjt@google.com, pavel@ucw.cz, tj@kernel.org,
	dhaval.giani@oracle.com, qperret@google.com,
	tim.c.chen@linux.intel.com
Subject: Re: [PATCH v4 3/4] sched: Allow sched_{get,set}attr to change latency_nice of the task
Date: Tue, 25 Feb 2020 12:24:09 +0530	[thread overview]
Message-ID: <20200225065409.GK28029@codeaurora.org> (raw)
In-Reply-To: <20200224085918.16955-4-parth@linux.ibm.com>

On Mon, Feb 24, 2020 at 02:29:17PM +0530, Parth Shah wrote:

[...]

> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 65b6c00d6dac..e1dc536d4ca3 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -4723,6 +4723,8 @@ static void __setscheduler_params(struct task_struct *p,
>  	p->rt_priority = attr->sched_priority;
>  	p->normal_prio = normal_prio(p);
>  	set_load_weight(p, true);
> +
> +	p->latency_nice = attr->sched_latency_nice;
>  }

We don't want this when SCHED_FLAG_LATENCY_NICE is not set in
attr->flags.

The user may pass SCHED_FLAG_KEEP_PARAMS | SCHED_FLAG_LATENCY_NICE to
change only latency nice value. So we have to update latency_nice
outside __setscheduler_params(), I think.

>  
>  /* Actually do priority change: must hold pi & rq lock. */
> @@ -4880,6 +4882,13 @@ static int __sched_setscheduler(struct task_struct *p,
>  			return retval;
>  	}
>  
> +	if (attr->sched_flags & SCHED_FLAG_LATENCY_NICE) {
> +		if (attr->sched_latency_nice > MAX_LATENCY_NICE)
> +			return -EINVAL;
> +		if (attr->sched_latency_nice < MIN_LATENCY_NICE)
> +			return -EINVAL;
> +	}
> +
>  	if (pi)
>  		cpuset_read_lock();
>  
> @@ -4914,6 +4923,9 @@ static int __sched_setscheduler(struct task_struct *p,
>  			goto change;
>  		if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP)
>  			goto change;
> +		if (attr->sched_flags & SCHED_FLAG_LATENCY_NICE &&
> +		    attr->sched_latency_nice != p->latency_nice)
> +			goto change;
>  
>  		p->sched_reset_on_fork = reset_on_fork;
>  		retval = 0;
> @@ -5162,6 +5174,9 @@ static int sched_copy_attr(struct sched_attr __user *uattr, struct sched_attr *a
>  	    size < SCHED_ATTR_SIZE_VER1)
>  		return -EINVAL;
>  
> +	if ((attr->sched_flags & SCHED_FLAG_LATENCY_NICE) &&
> +	    size < SCHED_ATTR_SIZE_VER2)
> +		return -EINVAL;
>  	/*
>  	 * XXX: Do we want to be lenient like existing syscalls; or do we want
>  	 * to be strict and return an error on out-of-bounds values?
> @@ -5391,6 +5406,8 @@ SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr,
>  	else
>  		kattr.sched_nice = task_nice(p);
>  
> +	kattr.sched_latency_nice = p->latency_nice;
> +

Can you consider printing latency_nice value in proc_sched_show_task() in this
patch/series?

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.

  reply	other threads:[~2020-02-25  6:54 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-24  8:59 [PATCH v4 0/4] Introduce per-task latency_nice for scheduler hints Parth Shah
2020-02-24  8:59 ` [PATCH v4 1/4] sched: Introduce latency-nice as a per-task attribute Parth Shah
2020-02-24  8:59 ` [PATCH v4 2/4] sched/core: Propagate parent task's latency requirements to the child task Parth Shah
2020-02-25  6:32   ` Pavan Kondeti
2020-02-25  8:16     ` Parth Shah
2020-02-24  8:59 ` [PATCH v4 3/4] sched: Allow sched_{get,set}attr to change latency_nice of the task Parth Shah
2020-02-25  6:54   ` Pavan Kondeti [this message]
2020-02-25 15:03     ` Parth Shah
2020-02-26  3:44       ` Pavan Kondeti
2020-02-24  8:59 ` [PATCH v4 4/4] sched/core: Add permission checks for setting the latency_nice value Parth Shah
2020-02-24 13:29   ` Qais Yousef
2020-02-25  6:47     ` Parth Shah
2020-02-27 11:44       ` Qais Yousef
2020-02-27 14:46         ` chris hyser
2020-02-24 23:08   ` chris hyser

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