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From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: Arjan van de Ven <arjan@infradead.org>
Cc: kosaki.motohiro@jp.fujitsu.com, linux-kernel@vger.kernel.org,
	torvalds@linux-foundation.org, dwmw2@infradead.org,
	drepper@redhat.com, mingo@elte.hu, tglx@tglx.de
Subject: Re: [PATCH 12/13] hrtimer: create a "timer_slack" field in the task struct
Date: Tue, 30 Sep 2008 14:16:09 +0900 (JST)	[thread overview]
Message-ID: <20080930140930.ED5B.KOSAKI.MOTOHIRO@jp.fujitsu.com> (raw)
In-Reply-To: <20080901161423.59ebf2fc@infradead.org>

Hi Arjan, 

Sorry for _really_ late responce.
I recently found this patch in linux-next.

In general, I like this patch.
However,

> +		case PR_SET_TIMERSLACK:
> +			if (arg2 <= 0)
> +				current->timer_slack_ns =
> +					current->default_timer_slack_ns;
> +			else
> +				current->timer_slack_ns = arg2;
> +			break;
>  		default:
>  			error = -EINVAL;
>  			break;

I wonder to why PR_SET_TIMERSLACK decreasing doesn't need root privilege.

example,
nice() systemcall is
  - nice increasing (pirority decreasing) doesn't need root privilege.
  - nice decreasing (priority incriasing) need root privilege.

So, I think time slack setting need similar one.
Otherwise, non-privilege user can increase power consumpsion easily by PR_SET_TIMERSLACK.

What do you think?



  parent reply	other threads:[~2008-09-30  5:16 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-09-01 23:03 [PATCH 0/13] Turn hrtimers into a range capable timer Arjan van de Ven
2008-09-01 23:05 ` [PATCH 1/13] hrtimer: add abstraction functions for accessing the "expires" member Arjan van de Ven
2008-09-01 23:05 ` [PATCH 2/13] hrtimer: convert kvm to the new hrtimer apis Arjan van de Ven
2008-09-01 23:06 ` [PATCH 3/13] hrtimer: convert timerfd " Arjan van de Ven
2008-09-01 23:07 ` [PATCH 4/13] hrtimer: convert net::sched_cbq " Arjan van de Ven
2008-09-01 23:08 ` [PATCH 5/13] hrtimer: convert kernel/* " Arjan van de Ven
2008-09-01 23:09 ` [PATCH 6/13] hrtimer: convert powerpc/oprofile " Arjan van de Ven
2008-09-01 23:09 ` [PATCH 7/13] hrtimer: convert kvm-ia64 " Arjan van de Ven
2008-09-01 23:10 ` [PATCH 8/13] hrtimer: convert s390 " Arjan van de Ven
2008-09-01 23:11 ` [PATCH 9/13] hrtimer: convert sound/ " Arjan van de Ven
2008-09-01 23:12 ` [PATCH 10/13] hrtimer: rename the "expires" struct member to avoid accidental usage Arjan van de Ven
2008-09-01 23:12 ` Arjan van de Ven
2008-09-01 23:13 ` [PATCH 11/13] hrtimer: turn hrtimers into range timers Arjan van de Ven
2008-09-02  8:22   ` Peter Zijlstra
2008-09-02 11:08     ` Peter Zijlstra
2008-09-02 11:15       ` Peter Zijlstra
2008-09-02 13:06       ` Arjan van de Ven
2008-09-02 13:05     ` Arjan van de Ven
2008-09-02 13:47       ` Peter Zijlstra
2008-09-02 16:02         ` Arjan van de Ven
2008-09-01 23:14 ` [PATCH 12/13] hrtimer: create a "timer_slack" field in the task struct Arjan van de Ven
2008-09-02 10:04   ` Pavel Machek
2008-09-02 13:03     ` Arjan van de Ven
2008-09-08 13:27       ` Pavel Machek
2008-09-08 13:40         ` Arjan van de Ven
2008-09-08 14:15           ` Pavel Machek
2008-09-08 14:22             ` Arjan van de Ven
2008-09-13 16:24               ` Pavel Machek
2008-09-14 15:21             ` Ulrich Drepper
2008-09-14 15:27               ` Arjan van de Ven
2008-09-14 15:57               ` Pavel Machek
2008-09-14 16:04                 ` Ulrich Drepper
2008-09-14 16:14                   ` Arjan van de Ven
2008-09-17  7:42                   ` Pavel Machek
2008-09-30  5:16   ` KOSAKI Motohiro [this message]
2008-09-30  8:28     ` Arjan van de Ven
2008-09-30  8:54       ` KOSAKI Motohiro
2008-09-01 23:14 ` [PATCH 13/13] hrtimer: make select() and poll() use the hrtimer range feature Arjan van de Ven
2008-09-02  8:22   ` Peter Zijlstra
2008-09-02 16:03     ` Arjan van de Ven
2008-09-06 14:56 ` [PATCH 0/13] Turn hrtimers into a range capable timer Ingo Molnar
2008-09-06 16:30   ` Arjan van de Ven
2008-09-06 16:33     ` Ingo Molnar
2008-09-12  3:39 ` Rusty Russell
2008-09-12  5:42   ` Arjan van de Ven
2008-09-12 20:24   ` Thomas Gleixner

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