Subject: Re: [ANNOUNCE] Linux 2.6 Real Time Kernel
From: Daniel Walker <dwalker@mvista.com>
Reply-To: dwalker@mvista.com
To: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@osdl.org>, sdietrich@mvista.com,
       linux-kernel@vger.kernel.org, abatyrshin@ru.mvista.com,
       amakarov@ru.mvista.com, emints@ru.mvista.com, ext-rt-dev@mvista.com,
       hzhang@ch.mvista.com, yyang@ch.mvista.com
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Date: 12 Oct 2004 11:50:49 -0700
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On Mon, 2004-10-11 at 13:49, Ingo Molnar wrote:
> * Daniel Walker <dwalker@mvista.com> wrote:
> 
> what do you think about the PREEMPT_REALTIME stuff in -T4? Ideally, if
> you agree with the generic approach, the next step would be to add your
> priority inheritance handling code to Linux semaphores and
> rw-semaphores. The sched.c bits for that looked pretty straightforward.
> The list walking is a bit ugly but probably unavoidable - the only other
> option would be 100 priority queues per semaphore -> yuck.


I think patch size is an issue, but I also think that , eventually, we
should change all spin_lock calls that actually lock a mutex to be more
distinct so it's obvious what is going on. Sven and I both agree that
this should be addressed. Is this a non-issue for you? What does the
community want? I don't find your code or ours acceptable in it's
current form , due to this issue.

With the addition of PREEMPT_REALTIME it looks like you more than
doubled the size of voluntary preempt. I really feel that it should
remain as two distinct patches. They are dependent , but the scope of
the changes are too vast to lump it all together. 

Daniel Walker

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