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Date:   Tue, 11 Dec 2018 09:41:40 -0500
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Petr Mladek <pmladek@suse.com>
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        Kieran Bingham <kieran.bingham@ideasonboard.com>,
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Subject: Re: [RFC v3 11/19] kunit: add Python libraries for handing KUnit
 config and kernel
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On Tue, 11 Dec 2018 15:09:26 +0100
Petr Mladek <pmladek@suse.com> wrote:

> > We have liburcu already, which is good.  The main sticking points are:
> > 
> >  - printk has started adding a lot of %pX enhancements which printf
> >    obviously doesn't know about.  
> 
> I wonder how big problem it is and if it is worth using another
> approach.

No, please do not change the %pX approach.

> 
> An alternative would be to replace them with helper functions
> the would produce the same string. The meaning would be easier
> to understand. But concatenating with the surrounding text
> would be less elegant. People might start using pr_cont()
> that is problematic (mixed lines).
> 
> Also the %pX formats are mostly used to print context of some
> structures. Even the helper functions would need some maintenance
> to keep them compatible.
> 
> BTW: The printk() feature has been introduced 10 years ago by
> the commit 4d8a743cdd2690c0bc8 ("vsprintf: add infrastructure
> support for extended '%p' specifiers").

trace-cmd and perf know about most of the %pX data and how to read it.
Perhaps we can extend the libtraceevent library to export a generic way
to read data from printk() output for other tools to use.

-- Steve