Re: [PATCH v4 7/7] kernel.h: drop trace_printk.h

[Steven Rostedt]

On Thu, 25 Dec 2025 12:09:29 -0500
"Yury Norov (NVIDIA)" <yury.norov@xxxxxxxxx> wrote:

> The trace_printk.h header is debugging-only by nature, but now it's
> included by almost every compilation unit via kernel.h.
> 
> Removing trace_printk.h saves 1.5-2% of compilation time on my
> Ubuntu-derived x86_64/localyesconfig.
> 
> There's ~30 files in the codebase, requiring trace_printk.h for
> non-debugging reasons: mostly to disable tracing on panic or under
> similar conditions. Include the header for those explicitly.
> 
> This implicitly decouples linux/kernel.h and linux/instruction_pointer.h
> as well, because it has been isolated to trace_printk.h early in the
> series.
> 
> Signed-off-by: Yury Norov (NVIDIA) <yury.norov@xxxxxxxxx>

I'm still against this patch. It means every time someone adds
trace_printk() they need to add the header for it.

trace_printk() should be as available to the kernel as printk() is. If
there's a place that one can add printk() without adding a header, then
they should be able to add trace_printk() to that same location without
adding any header. If that's not the case, then I'm adding an official

 Nacked-by: Steven Rostedt <rostedt@xxxxxxxxxxx>

I'm fine for trying other ways to speed up the compilation, but removing
full access to trace_printk() isn't one of them.

-- Steve