Date: Wed, 30 Mar 2005 08:50:11 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Esben Nielsen <simlo@phys.au.dk>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [patch] Real-Time Preemption, -RT-2.6.12-rc1-V0.7.41-07
Message-ID: <20050330065011.GA18417@elte.hu>
References: <Pine.OSF.4.05.10503242307330.25274-100000@da410.phys.au.dk> <Pine.LNX.4.58.0503261047190.27746@localhost.localdomain> <1112164313.3691.100.camel@localhost.localdomain>
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* Steven Rostedt <rostedt@goodmis.org> wrote:

> OK, I'm declaring defeat here. I've been fighting race conditions all 
> day, and it's now 1 in the morning where I live. It looks like this 
> implementation has no other choice but to have the waking up "pending 
> owner" take the wait_list lock once again.  How heavy of a overhead is 
> that really?

as i mentioned it before, taking a lock is not a big issue at all. Since 
you have to touch the lock data structure anyway (and all of it fits 
into a single cacheline), it doesnt really matter whether it's atomic 
flag setting/clearing, or raw spinlock based.

later on, once things are stable and well-understood, we can still 
attempt to micro-optimize it.

	Ingo
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