Re: [GIT PULL] tracing: Updates for 7.2

[Sebastian Andrzej Siewior <bigeasy@linutronix.de>]

On 2026-06-19 07:35:15 [-0700], Linus Torvalds wrote:
> On Fri, 19 Jun 2026 at 05:15, Steven Rostedt <rostedt@goodmis.org> wrote:
> >
> > Many developers use trace_printk() over printk().
> 
> You're on some bad drugs, Steven.
> 
> By "many developers" you clearly must have meant "almost nobody".

I do use it for debugging all the time. The alternative is printk but it
is "slower" if it throws everything to the UART which I prefer to limit
to BUG/WARN kind of messages. Also it does not record the context where
this comes from which is often helpful.
Afaik it is the only to debug printk.

> > Requiring people to add that include for every use case would
> > severely limit debugging of the kernel. Would you be OK if we did
> > the same for printk?
> 
> Stop making inane and silly arguments that have nothing to do with
> reality.
> 
> The two are not the same:
> 
>   $ git grep -wl printk | wc -l 3212 $ git grep -wl trace_printk | wc
>   -l 50
> 
> and making them sound remotely similar is just making you look dishonst.
> 
> Look, the attached patch makes my defconfig build cleanly, and makes a
> 
>   $ touch include/linux/trace_printk.h
> 
> cause my recompile to build just a handful of files. While touching
> linux/kernel.h causes thousands of files to be re-build.
> 
> That's a whopping
> 
>  6 files changed, 6 insertions(+), 1 deletion(-)
> 
> to make my tree build without including <linux/trace_printk.h> everywhere.
> 
> Now, that's _just_ my defconfig, and the full build clearly has a
> handful of other cases. From a quick look, mostly in the 'samples'
> directory.
> 
> But it looks like a *handful* of other cases.
> 
> Now, if the same was true for printk(), I'd happily split that into
> some other header too.
> 
> But it isn't.
> 
> Because we live in reality.
> 
>                Linus

Sebastian