From: Thomas Gleixner <tglx@linutronix.de>
To: Esben Nielsen <simlo@phys.au.dk>
Cc: Ingo Molnar <mingo@elte.hu>, linux-kernel@vger.kernel.org
Subject: Re: PI patch against 2.6.16-rt9
Date: Tue, 28 Mar 2006 23:36:42 +0200 [thread overview]
Message-ID: <1143581802.5344.229.camel@localhost.localdomain> (raw)
In-Reply-To: <Pine.LNX.4.44L0.0603282202250.22822-100000@lifa02.phys.au.dk>
On Tue, 2006-03-28 at 22:17 +0100, Esben Nielsen wrote:
> I think we talk about the situation
No, we talk about existing lock chains L(0) --> L(n).
> B locks 1 C locks 2 D locks 3
> B locks 2, boosts C and block
> A locks 2
> A is boost B
> A drop it's spinlocks and is preempted
> C unlocks 2 and auto unboosts
> B is running
> B locks 3, boosts C and blocks
> A gets a CPU again
> A boosts B
> A boosts D
>
> Is there anything wrong with that?
> And in the case where A==D there indeed is a deadlock which will be
> detected.
If you get to L(x) the underlying dependencies might have changed
already as well as the dependencies x ... n. We might get false
positives in the deadlock detection that way, as a deadlock is an
"atomic" state.
tglx
next prev parent reply other threads:[~2006-03-28 21:35 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-26 23:42 PI patch against 2.6.16-rt9 Esben Nielsen
2006-03-26 23:47 ` Ingo Molnar
2006-03-27 0:07 ` Esben Nielsen
2006-03-27 0:11 ` Esben Nielsen
2006-03-27 0:21 ` Ingo Molnar
2006-03-27 15:00 ` Esben Nielsen
2006-03-27 23:05 ` Esben Nielsen
2006-03-28 21:02 ` Ingo Molnar
2006-03-28 20:55 ` Ingo Molnar
2006-03-28 21:17 ` Esben Nielsen
2006-03-28 21:24 ` Ingo Molnar
2006-03-28 22:51 ` Esben Nielsen
2006-03-29 7:14 ` Ingo Molnar
2006-03-29 7:59 ` Esben Nielsen
2006-03-29 12:35 ` Ingo Molnar
2006-03-28 21:36 ` Thomas Gleixner [this message]
2006-03-28 22:23 ` Esben Nielsen
2006-03-28 22:42 ` Thomas Gleixner
2006-03-28 23:34 ` Esben Nielsen
2006-03-28 23:59 ` Thomas Gleixner
2006-03-29 12:29 ` Ingo Molnar
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