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Date: Mon, 13 Dec 2004 23:31:53 +0100
From: Ingo Molnar <mingo@elte.hu>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Mark Johnson <Mark_H_Johnson@RAYTHEON.COM>,
       Amit Shah <amit.shah@codito.com>,
       Karsten Wiese <annabellesgarden@yahoo.de>, Bill Huey <bhuey@lnxw.com>,
       Adam Heath <doogie@debian.org>, emann@mrv.com,
       Gunther Persoons <gunther_persoons@spymac.com>,
       "K.R. Foley" <kr@cybsft.com>, LKML <linux-kernel@vger.kernel.org>,
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       Thomas Gleixner <tglx@linutronix.de>,
       Michal Schmidt <xschmi00@stud.feec.vutbr.cz>
Subject: Re: [patch] Real-Time Preemption, -RT-2.6.10-rc2-mm3-V0.7.32-6
Message-ID: <20041213223153.GA6793@elte.hu>
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* Steven Rostedt <rostedt@goodmis.org> wrote:

> [RFC] Has there been previously any thought of adding priority
> inheriting wait queues. [...]

this will make sense at a certain point.

> [...] it would really help to solve the problem of a high priority
> process waiting for an interrupt that can be starved by other high
> priority processes.

the primary use i think would be kernel-internal task <-> task
waitqueues such as the futex queues, to transport the effects of RT
priorities across waitqueues as well. IRQ related waitqueues are a nice
'side-effect'.

another next step would be to transport PI effects to userspace code,
for user-controlled synchronization objects such as futexes or e.g. SysV
semaphores.

	Ingo