linux-kernel - Re: Kaffeine problem with CFS

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: <20070418160722.GB31925@holomorphy.com>
Date:	Wed, 18 Apr 2007 09:07:22 -0700
From:	William Lee Irwin III <wli@...omorphy.com>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	"S.??a??lar Onur" <caglar@...dus.org.tr>,
	Christoph Pfister <christophpfister@...il.com>,
	linux-kernel@...r.kernel.org,
	Michael Lothian <mike@...eburn.co.uk>,
	Christophe Thommeret <hftom@...e.fr>,
	Jurgen Kofler <kaffeine@....net>,
	Ulrich Drepper <drepper@...hat.com>
Subject: Re: Kaffeine problem with CFS

On Wed, Apr 18, 2007 at 05:48:11PM +0200, Ingo Molnar wrote:
>  static void requeue_task_fair(struct rq *rq, struct task_struct *p)
>  {
>  	dequeue_task_fair(rq, p);
>  	p->on_rq = 0;
> -	enqueue_task_fair(rq, p);
> +	/*
> +	 * Temporarily insert at the last position of the tree:
> +	 */
> +	p->fair_key = LLONG_MAX;
> +	__enqueue_task_fair(rq, p);
>  	p->on_rq = 1;
> +
> +	/*
> +	 * Update the key to the real value, so that when all other
> +	 * tasks from before the rightmost position have executed,
> +	 * this task is picked up again:
> +	 */
> +	p->fair_key = rq->fair_clock - p->wait_runtime + p->nice_offset;

At this point you might as well call the requeue operation something
having to do with yield. I also suspect what goes on during the timer
tick may eventually become something different from requeueing the
current task, and furthermore class-dependent.


-- wli
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/