Date: Mon, 16 Jan 2006 02:53:33 -0800
To: Esben Nielsen <simlo@phys.au.dk>
Cc: Ingo Molnar <mingo@elte.hu>, Steven Rostedt <rostedt@goodmis.org>,
       david singleton <dsingleton@mvista.com>, linux-kernel@vger.kernel.org,
       "Bill Huey (hui)" <billh@gnuppy.monkey.org>
Subject: Re: RT Mutex patch and tester [PREEMPT_RT]
Message-ID: <20060116105333.GA19617@gnuppy.monkey.org>
References: <20060115042449.GA9871@gnuppy.monkey.org> <Pine.LNX.4.44L0.0601160926360.4219-100000@lifa01.phys.au.dk> <20060116102255.GA19401@gnuppy.monkey.org>
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From: Bill Huey (hui) <billh@gnuppy.monkey.org>
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On Mon, Jan 16, 2006 at 02:22:55AM -0800, Bill Huey wrote:
> On Mon, Jan 16, 2006 at 09:35:42AM +0100, Esben Nielsen wrote:
> > On Sat, 14 Jan 2006, Bill Huey wrote:
> > I am not precisely sure what you mean by "false reporting".
> > 
> > Handing off BKL is done in schedule() in sched.c. I.e. if B owns a normal
> > mutex, A will give BKL to B when A calls schedule() in the down-operation
> > of that mutex.
> 
> Task A holding BKL would have to drop BKL when it blocks against a mutex held
> by task B in my example and therefore must hit schedule() before any pi boost
> operation happens. I'll take another look at your code just to see if this is
> clear.

Esben,

Ok, I see what you did. Looking through the raw patch instead of the applied
sources made it not so obvious it me. Looks the logic for it is there to deal
with that case, good. I like the patch, but it does context switch twice as
much it seems which might a killer.

bill

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