Date: Wed, 14 Jan 2009 12:21:31 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: mingo@elte.hu, torvalds@linux-foundation.org, paulmck@linux.vnet.ibm.com,
       ghaskins@novell.com, matthew@wil.cx, andi@firstfloor.org,
       chris.mason@oracle.com, linux-kernel@vger.kernel.org,
       linux-fsdevel@vger.kernel.org, linux-btrfs@vger.kernel.org,
       tglx@linutronix.de, npiggin@suse.de, pmorreale@novell.com,
       SDietrich@novell.com, dmitry.adamushko@gmail.com, hannes@cmpxchg.org
Subject: Re: [GIT PULL] adaptive spinning mutexes
Message-Id: <20090114122131.021e96b0.akpm@linux-foundation.org>
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On Wed, 14 Jan 2009 20:50:50 +0100
Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:

> On Wed, 2009-01-14 at 11:36 -0800, Andrew Morton wrote:
> 
> > Do people enable CONFIG_SCHED_DEBUG?
> 
> Well, I have it always enabled, but I've honestly no idea if that makes
> me weird.

It'd be weird if you're not weird.

> > CONFIG_DEBUG_MUTEXES=n, CONFIG_SCHED_DEBUG=y is getting to be a pretty
> > small subset?
> 
> Could be, do you fancy me doing a sysctl? shouldn't be hard.

The /sys/debug knob depends upon CONFIG_SCHED_DEBUG, I assume?

umm, yes, I do think that it would be prudent to make this control
unconditionally available.  Experience tells us that any regressions
which this change causes could take a long time to turn up - sometimes
years.  By which time the people who are reporting the regressions are
running packaged kernels, and if that packaged kernel didn't enable
CONFIG_SCHED_DEBUG, we're a bit screwed.

Did we end up deciding to remove the CONFIG_DEBUG_MUTEXES=n dependency?
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