On 6/22/26 1:34 AM, Peter Zijlstra wrote:

On Sun, Jun 21, 2026 at 05:34:30AM -0400, Steven Rostedt wrote:

quoted

There's been complaints about trace_printk() being defined in kernel.h as it
can increase the compilation time. As it is only used by some developers for
debugging purposes, it should not be in kernel.h causing lots of wasted CPU
cycles for those that do not ever care about it.

Instead, add a CONFIG_TRACE_PRINTK_DEBUGGING option that developers that do
use it can set and not have to always remember to add #include <linux/trace_printk.h>
to the files they add trace_printk() while debugging. It also means that
those that do not have that config set will not have to worry about wasted
CPU cycles as it is only include in the CFLAGS when the option is set, and
its completely ignored otherwise.

Did you forget your C 101 class? If you use a function, you gotta
include the relevant header.

Also item #1 in Documentation/process/submit-checklist.rst.

You don't see userspace saying: 'Hey, you know what, perhaps we should
add stdio.h to every other header, just in case someone wants to
printf()' either.

I really don't understand your argument. Yes, maybe someone will forget
and then either their editor (if they have a halfway modern setup with
LSP enabled) or their build will complain, but so what? This is all
trivial stuff, surely we have more pressing matters to concern outselves
with?

-- 
~Randy