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Date: Tue, 17 Apr 2007 10:57:03 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Nick Piggin <npiggin@suse.de>
Cc: Davide Libenzi <davidel@xmailserver.org>,
       Gene Heskett <gene.heskett@gmail.com>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Linus Torvalds <torvalds@linux-foundation.org>,
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       Con Kolivas <kernel@kolivas.org>, Mike Galbraith <efault@gmx.de>,
       Arjan van de Ven <arjan@infradead.org>,
       Peter Williams <pwil3058@bigpond.net.au>,
       Thomas Gleixner <tglx@linutronix.de>, caglar@pardus.org.tr,
       Willy Tarreau <w@1wt.eu>, Dmitry Adamushko <dmitry.adamushko@gmail.com>
Subject: Re: [patch] CFS (Completely Fair Scheduler), v2
Message-ID: <20070417085703.GA16645@elte.hu>
References: <20070416220715.GA4071@elte.hu> <200704170053.58611.gene.heskett@gmail.com> <20070417061849.GA12385@elte.hu> <Pine.LNX.4.64.0704170053410.30516@alien.or.mcafeemobile.com> <20070417081857.GD20026@wotan.suse.de> <20070417082628.GD5076@elte.hu> <20070417084153.GE20026@wotan.suse.de>
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* Nick Piggin <npiggin@suse.de> wrote:

> >                   list_add_tail(&p->run_list, &current->run_list);
[...]
> > shouldnt the list_add_tail() be list_add(), so that task pickup sees 
> > the child first? [...]
[...]
> I think that it works because the list we're adding to is not the 
> normal runqueue list head, but the parent's list_head on that 
> runqueue. Which adds the child directly ahead of the parent... I 
> think?

yeah, you are right, i was confused: list_add() adds _after_ the head, 
list_add_tail() adds _before_ the head - and in the middle of the list 
if we do a list_add_tail() it adds before that entry. So everything's 
fine and working as expected :)

	Ingo