Re: [PATCH v2 7/7] mm/tracing: introduce max_vma_count_exceeded trace event

[Steven Rostedt]

On Thu, 18 Sep 2025 12:38:56 +0100
Pedro Falcato <pfalcato@xxxxxxx> wrote:

> Isn't the usual problem with that approach, that of static functions/static
> inline functions? I was tracing through a problem a few months ago, and man
> I really did think "wouldn't it be nice to have a tracepoint instead of fishing
> around for kprobe spots".
> 
> Not that I particularly think a tracepoint is super worth it in this case, but,
> y'know.

Yes, it would be useful. The issue is that tracepoints are not free. They
do increase the I$ hit and take up memory.

If you're going to inject a tracepoint somewhere, at least extract some
useful information from that spot. If you can't think of anything to track,
then it's not worth a tracepoint.

If one really wants a way to track something, they could add a static
branch that would call a function when enabled that could be traced. They
would also need a way to enable that static branch.

-- Steve