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From: Yong Zhang <yong.zhang0@gmail.com>
To: John Kacur <jkacur@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Clark Williams <clark.williams@gmail.com>,
	RT <linux-rt-users@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: lockdep splat with 3.2-rc2-rt3+
Date: Wed, 30 Nov 2011 16:33:24 +0800	[thread overview]
Message-ID: <20111130083324.GA1632@zhy> (raw)
In-Reply-To: <CAONaPpHnu8VADg_EGQNrqsyhrVsJ2oOFMB4FyK-94qu5n-NEEQ@mail.gmail.com>

On Thu, Nov 24, 2011 at 11:50:06PM +0100, John Kacur wrote:
> So, as a little experiment, on v3.2.0-rc2-rt3
> I redefined MAX_LOCKDEP_ENTRIES from 16384UL to 32768UL
> 
> Then from /proc/lockdep_stats
> 
> I got
>  direct dependencies:                 18026 [max: 32768]
> 
> The fact that 18026 is only a little larger than the normal max (by 1642)
> to me is another indication that, this is not a case of something in
> lockdep going out of control that needs to be fixed, but just another
> indication that in some circumstances it would be legitimate to raise
> the value.

Yeah, seems the reason is in RT we have no dedicated softirq-context
anymore, IOW, both process-context and softirq-context are taken as
process-context. That will increase the usage of lockdep entries
because we expand the scope of process-context.

Thanks,
Yong

      reply	other threads:[~2011-11-30  8:33 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-11-20 17:36 lockdep splat with 3.2-rc2-rt3+ Clark Williams
2011-11-21  8:44 ` John Kacur
2011-11-24 22:50   ` John Kacur
2011-11-30  8:33     ` Yong Zhang [this message]

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