Re: [PATCH 3/3] kernel/smp: add more data to CSD lock debugging

[Jürgen Groß]

On 01.03.21 16:45, Peter Zijlstra wrote:
> On Sun, Feb 28, 2021 at 04:07:04PM -0800, Paul E. McKenney wrote:
> > On Fri, Feb 26, 2021 at 10:05:51PM +0100, Peter Zijlstra wrote:
> > > On Fri, Feb 26, 2021 at 10:12:05AM -0800, Paul E. McKenney wrote:
> > > > On Fri, Feb 26, 2021 at 05:38:44PM +0100, Peter Zijlstra wrote:
> > > > > I hate all of this, but if this will finally catch the actual problem,
> > > > > we can then revert all this, so sure.
> > > >
> > > > OK, I will bite...  What exactly do you hate about it?
> > >
> > > It's ugly and messy. We're basically commiting a debug session. Normally
> > > gunk like this is done in private trees, then we find the problem and
> > > fix that and crap like this never sees the light of day.
> >
> > Is your hatred due to the presence of debug code at all, or a belief that
> > this code is unlikely to be useful in any subsequent IPI-related bug hunt?
>
> The clutter, mostly I think. There's a lot of debug sprinkled about.

I agree.

In case we are able to identify the root cause of the problem I think
it would be no problem to revert this patch and put a comment into smp.c
naming the commit-id of this patch and what it was good for. This will
enable future bug hunters to make use of the patch without spoiling the
code for others.


Juergen

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